CN100590349C - Planar illuminating device - Google Patents

Abstract

Provided is a planar lighting device having a first and a second light sources arranged at a given distance apart from each other and a light guide plate arranged between the first and second light sources. The light guide plate includes a light exit plane, a first light entrance plane facing the first light source and containing one side of the light exit plane, and a second light entrance planefacing the second light source and containing the opposite side to the one side, and has a shape growing thicker from the first and second light entrance planes toward the center. The light guide plate contains scattering particles for scattering light entering through the first and second light entrance planes and propagating inside by a ratio satisfying 1.1<=PhiNPLGKC<=8.2.

Description

Planar illuminating device

Technical field

The present invention relates to a kind of planar illuminating device that is applied to liquid crystal indicator etc.

Background technology

Use rear side irradiates light in the liquid crystal indicator, the backlight unit that display panels is thrown light on from display panels.Backlight unit make light scattering that illuminating light source sends with the LGP of irradiating liquid crystal display floater, make member such as the uniform prism thin plate of light that penetrates from LGP and scattering thin plate and constitute.

At present, the backlight unit of large-scale LCD TV is to be main flow (for example with reference to real open flat 5-4133 communique) in the mode that LGP is disposed at the so-called full run-down type directly over the illuminating light source.In this mode, will be disposed at the back side of display panels as a plurality of cold-cathode tubes of light source, with inside as the reflecting surface of white to guarantee uniform light quantity distribution and essential brightness.

But, even in order to make light quantity distribution in the backlight unit of directly-below type, must be with respect to the thickness of display panels vertical direction for about 30mm.Backlight unit expectation from now on is further slim, but aspect full run-down type, based on the viewpoint of light quantity inequality, thinks the backlight unit that is difficult to realize having the following thickness of 10mm.

So, as slim backlight unit, have motion proposed series connection (tandem) mode (for example with reference to the spy open flat 2-208631 communique, the spy opens flat 11-288611 communique and the spy opens the 2001-312916 communique).

Patent documentation 1: real Kai Ping-No. 4133 communique

Patent documentation 2: the spy opens flat 2-208631 communique

Patent documentation 3: the spy opens flat 11-288611 communique

Patent documentation 4: the spy opens the 2001-312916 communique

But, in the backlight unit of series connection (タ Application デ system) mode, though can realize slimming,, because the relation of the relative size of cold-cathode tube and reflecting plate, thus aspect light utilization efficiency than full run-down type difference.In addition, using when cold-cathode tube is contained in the LGP of shape of the groove that forms on LGP, if will make the thickness attenuation of LGP, then be disposed at groove cold-cathode tube directly over brightness strengthen, make the brightness disproportionation of light emergence face become obvious.

Therefore, the slimming of the backlight unit of series system is limited.

Summary of the invention

The present invention sets up the project in view of such situation, and it is a kind of for slim shape and can penetrate evenly and the planar illuminating device of the illumination light that brightness disproportionation is few that its purpose is to provide.

In order to solve above-mentioned problem, first aspect present invention provides a kind of planar illuminating device, and a kind of planar illuminating device wherein, possesses: leave and first light source and the secondary light source that dispose with predetermined distance; Be disposed at the LGP between described first light source and the described secondary light source, wherein, described LGP has: light emergence face; With described first light source mutually in the face of and comprise first light entrance face on one side of described light emergence face; With described secondary light source mutually in the face of and comprise second light entrance face of the opposite side on described one side, from described first light entrance face and described second light entrance face to central authorities, thickness is thickening gradually, comprise scattering particles, described scattering particles makes from first and second light entrance face incident of described LGP and in the light generation scattering of internal communication, and satisfies following formula (1):

1.1≤φ·N _P·L _G·K _C≤8.2 (1)

Wherein, establish that the scattering section of scattering particles is long-pending to be φ, 1/2nd the length of establishing the light incident direction of described LGP is L _G, the density of establishing scattering particles is N _P, establishing correction coefficient is K _C, make K _CBe more than 0.005 below 0.1.

In the planar illuminating device of first embodiment of the present invention, the profile of the described light emergence face of preferred described LGP is a rectangle.

In addition, in the planar illuminating device of first embodiment of the present invention, be preferably, be formed flatly the described light emergence face of described LGP, described LGP at the opposition side of described light emergence face, has first inclined plane and second inclined plane, described first inclined plane and the bisecting line of second inclined plane with respect to the described light emergence face parallel with described one side of described light emergence face tilt symmetrically and form.In addition, the polarization separating film that the polarized component of regulation is seen through, polarized component is in addition reflected on the described light emergence face of described LGP, forms as one with described LGP.

In addition, in the planar illuminating device of first embodiment of the present invention, be preferably, the described light emergence face of described LGP, first inclined plane and second inclined plane that are tilted symmetrically by the bisecting line with respect to the described light emergence face parallel with described one side of described light emergence face form, in addition, the face of the opposition side of described light emergence face also is to be formed by the 3rd inclined plane and the 4th inclined plane that the bisecting line with respect to the described light emergence face parallel with described one side of described light emergence face tilts symmetrically.

In addition, in the planar illuminating device of first embodiment of the present invention, be preferably, the described light emergence face of described LGP is formed by first inclined plane and second inclined plane that the bisecting line with respect to the described light emergence face parallel with described one side of described light emergence face tilts symmetrically, and is formed flatly the face of the opposition side of described light emergence face.

In addition, be preferably, described first light source and secondary light source all use led array and a plurality of lens and constitute, described led array is that a plurality of RGB-LED that possess red light emitting diodes, green LED and blue LED are listed configuration arranged side by side one, and described a plurality of lens are corresponding with the light emitting side of described red light emitting diodes, described green LED and described blue LED respectively and dispose.And be preferably, each of described a plurality of lens all is the globe lens of spherical transparent.

In addition, be preferably, described first light source and secondary light source all are led array, the support portion that described led array has a plurality of led chips and the described led chip that forms a line is supported, if the length of the direction vertical with the described light-emitting face of described LGP of described led chip is a, if the length of described led chip orientation is b, when the configuration space of establishing described led chip is p, then satisfy the relation of p＞b＞a.

And then, also be preferably, described first light source and described secondary light source all have two the above led array, and has a following formation, promptly adopt at least a method in mechanical connection method and the chemical connection process, interval between the described led chip of the described led chip of described led array and other described led array is left with predetermined distance and stacked.

In addition, be preferably, have two the above LGPs, will comprise the face on one side of the one side of described light emergence face of described LGP and described light entrance face, adjacent and dispose with the face on one side of the one side that comprises described light emergence face of other described LGP and the described plane of incidence.

At this, preferred described LGP disposes a plurality of scattered reflection bodies at least one face of the face except that described first light entrance face and described second light entrance face.

In addition, preferred described scattered reflection body is along with away from described first light entrance face and described second light entrance face and dispose closely more.

In addition, preferred described scattered reflection body is disposed at described first inclined plane and described second inclined plane.

Be preferably, the part of the described first light entrance face side of described LGP and the part of the described second light entrance face side are formed by the material different with other parts, when the refractive index that the refractive index at the material of the part of a part of establishing the described first light entrance face side and the described second light entrance face side is Nm, establish the material of other parts is Ni, satisfy the relation of Nm＞Ni.

And then, preferably, also have reflecting element, described reflecting element is configured in respectively on described first light entrance face described light emergence face, described first inclined plane near described first light entrance face, the described light emergence face near described second light entrance face and described second light entrance face described second inclined plane nearby nearby of described LGP.

In order to solve described problem, second aspect present invention provides a kind of planar illuminating device, and it possesses: keep apart in accordance with regulations and first light source and the secondary light source that dispose; Be disposed between described first light source and the secondary light source, and use the light conducting member that is close to many plastic optical fibers of laminated configuration each other and constitutes, described first light source is faced mutually and is disposed with an end face of described plastic optical fiber, described secondary light source is faced mutually and is disposed with another end face, described plastic optical fiber, comprise and make from two surface feeding sputterings and in the light generation scattering of internal communication and satisfy the scattering particles of following mathematical expression (1)

1.1≤Φ·N _P·L _G·K _C≤8.2 (1)

Wherein, establish that the scattering section of scattering particles is long-pending to be Φ, 1/2nd the length of establishing described plastic optical fiber is L _G, the density of establishing scattering particles is N _P, establishing correction coefficient is K _C, make K _CBe more than 0.005 below 0.1.

Be preferably, described light conducting member also has transparent housing, disposes described many plastic optical fibers in described housing inner stacks.

In addition, be preferably, described first light source and secondary light source all use led array and a plurality of lens and constitute, in the described led array with red light emitting diodes, green LED and blue LED with configuration side by side with every corresponding mode of described many plastic optical fibers, described a plurality of lens are corresponding with the light emitting side of described red light emitting diodes, described green LED and described blue LED respectively and dispose.

In the planar illuminating device of first aspect present invention, between first light source of in accordance with regulations interval separate configuration and secondary light source, dispose LGP, this LGP has the light emergence face that profile is a rectangle, first light entrance face of facing mutually with first light source, second plane of incidence of facing mutually with secondary light source, have along with from first light entrance face and second light entrance face to central authorities near the thickness shape of thickening gradually, and comprise the scattering particles that makes in the light generation scattering of internal communication, therefore, can realize slimming, simultaneously, can penetrate the less planar illumination light of even and uneven spot.

In addition, in the planar illuminating device of second aspect present invention, be close to and many plastic optical fibers of laminated configuration each other dividing at interval in accordance with regulations to use between first light source that is arranged and the secondary light source, and possess and comprise the light conducting member that makes at the scattering particles of the light generation scattering of internal communication, first light source is faced mutually and is disposed with an end face of plastic optical fiber, secondary light source is faced mutually and is disposed with another end face, therefore, can realize slimming, simultaneously, can penetrate the less planar illumination light of even and uneven spot.

Description of drawings

Figure 1A is the stereogram of summary that expression possesses the liquid crystal indicator of the related planar illuminating device of first embodiment of the present invention, and Figure 1B is its summary section.

Fig. 2 A is applied to the LGP of planar illuminating device involved in the present invention and the approximate vertical view of light source, and Fig. 2 B is its summary section.

Fig. 3 is the figure that schematically illustrates the configuring condition of a plurality of RGB-LED that use red, green and blue this light emitting diode of three types formation.

Fig. 4 is the schematic diagram of RGB-LED and coupled lens.

Fig. 5 is the Φ N that expression is measured _PL _GK _CAnd the result's of the relation between the light utilization efficiency figure.

Fig. 6 is result's the figure of the illumination of the light that sends from each different light conductor of particle density representing to measure respectively.

Fig. 7 is the figure of the relation of expression light utilization efficiency and uneven illumination and particle density.

Fig. 8 is result's the figure of the relation of the LGP measured of expression and light utilization efficiency.

Fig. 9 A～Fig. 9 D is a summary section of representing other routine LGP respectively.

Figure 10 A is the summary section of another routine LGP of expression, and Figure 10 B is the generalized schematic of amplifying the part of the LGP of expression shown in Figure 10 A.

Figure 11 A is to use the LGP of planar illuminating device of the present invention and the approximate vertical view of light source, and Figure 11 B is its summary section.

Figure 12 A is the approximate three-dimensional map of an embodiment that expression is applied to the formation of led array of the present invention, Figure 12 B is the outline elevation of the led chip of the led array shown in Figure 12 A, Figure 12 C is to use the outline elevation of formation of multilayer LED of the led array of Figure 12 A, and Figure 12 D is the summary side elevation of the heat sink embodiment of expression.

Figure 13 is the summary pie graph that the prism thin plate is disposed at as shown in Figure 1 the LGP backlight unit when getting on the light emergence face.

Figure 14 is the approximate vertical view that possesses the planar illuminating device of the LGP that is printed with the scattered reflection body on the inclined plane.

Figure 15 is the summary section that expression has one of the planar illuminating device example of transmitance adjustment part.

Figure 16 is the curve map that never possesses the relative brightness of the light that the light emergence face of the backlight unit of transmitance adjustment part sends.

Figure 17 is the shape that calculates based on Figure 16 of expression to brightness is the curve map of result of calculation of distribution that transmitance of the present invention is adjusted the pattern density of member that satisfies that calculated in 0.75 o'clock establishing maximal density c.

Figure 18 is expression from disposing the maximal density c that makes that calculates at Figure 17 is the curve map that 0.75 o'clock transmitance is adjusted the relative brightness of the light that the light emergence face of the planar illuminating device of member sends.

Figure 19 is expression to send the curve map that passes the result that light that colourity adjusts film measures from light source.

Figure 20 is expression to send and pass the curve map that colourity is adjusted the result that the light behind the film measures from other light source.

Figure 21 is expression to send and pass the curve map that colourity is adjusted the result that the light behind the film measures from other light source.

Figure 22 A is the approximate vertical view of other configuration example that can be applicable to the LGP of backlight unit of the present invention, and Figure 22 B is its summary section.

Figure 23 A is the approximate vertical view of another other configuration example that can be applicable to the LGP of backlight unit of the present invention, and Figure 23 B is its summary section.

Figure 24 is other routine summary section of the planar illuminating device of expression first embodiment of the invention.

Figure 25 A～Figure 25 C is other routine summary section of LGP of representing to be applied to the planar illuminating device of first embodiment of the present invention respectively.

Figure 26 is the summary section that other example of the planar illuminating device of expression first embodiment of the present invention constitutes.

Figure 27 is a summary pie graph of having used the planar illuminating device of a plurality of LGPs.

Figure 28 A is the approximate three-dimensional map of other embodiment of expression planar illuminating device, and Figure 28 B is the approximate three-dimensional map of the planar illuminating device shown in Figure 28 A, and Figure 28 C is the summary section of the length direction of the planar illuminating device shown in Figure 28 A.

Figure 29 A is the approximate three-dimensional map of another other embodiment of expression planar illuminating device, and Figure 29 B is the summary section of the length direction of the planar illuminating device shown in Figure 29 A.

Figure 30 is the outline elevation of one of the annular planar illuminating device of expression example.

Figure 31 is another routine outline elevation of the annular planar illuminating device of expression.

Figure 32 A is another routine outline elevation of the annular planar illuminating device of expression, and Figure 32 B is the profile of the planar illuminating device shown in Figure 32 A.

Figure 33 A is the schematic plan of the part of related light conducting member of second embodiment and the light source that uses in order to make light incide this light conducting member, and Figure 33 B is along the schematic cross sectional view of the B-B line of the light conducting member shown in Figure 33 A.

Figure 34 possesses the summary pie graph of the backlight unit that light conducting member is as shown in figure 33 arranged.

Among the figure:

2,120,141,180～backlight unit

4～display panels

6～driver element

10～liquid crystal indicator

12,122,142,190～light source

14～diffusion barrier

16～polarization separating film

18,28,38,144,151,153,155～LGP,

18a～light emergence face

18b～first inclined plane

18c～second inclined plane

18d～first light entrance face

18e～second light entrance face

20A, 20B～light mixing

22～reflection thin plate

24～led array

26,188～prism thin plate

28a～first inclined plane

28b～second inclined plane

28c～tabular surface

28d～first light entrance face

38a～first inclined plane

38b～second inclined plane

38c～the 3rd inclined plane

38d～the 4th inclined plane

82～light source

84～led array

86～LED

88,126～coupled lens

90～light conducting member

90a～light emergence face

92～optical fiber

94～housing

100～backlight unit

102～reflection thin plate

104,106～prism thin plate

108～scattering thin plate

124～led array

128～led chip

130～heat sink

132～multilayer LED array

140～scattered reflection body

146～mother metal

148,152,154,156～low-refraction member

182～reflecting member

184～transparent membrane

186～transmitance is adjusted body.

The specific embodiment

Based on embodiment shown in the drawings, describe the liquid crystal indicator that possesses planar illuminating device of the present invention in detail.

Figure 1A is the stereogram of summary of the liquid crystal indicator of the expression planar illuminating device that possesses first embodiment of the invention, Figure 1B is the summary section of liquid crystal indicator, in addition, Fig. 2 A is applied to the LGP of planar illuminating device of the present invention (hereinafter referred to as " backlight unit ") and the approximate vertical view of light source, and Fig. 2 B is the summary section of LGP.

The formation of liquid crystal indicator 10 has: the driver element 6 of backlight unit 2, the display panels 4 that is disposed at the light emergence face side of this backlight unit 2, driving display panels 4.

Display panels 4 applies electric field and changes the arrangement of this molecule the liquid crystal molecule part that is arranged in specific direction in advance, utilizes the change of refractive that results from the liquid crystal cells, display text, pattern, image etc. on the surface of display panels 4.

Driver element 6 is added in transparency electrode in the display panels 4 with voltage, change liquid crystal molecule towards the transmitance of controlling the light that passes display panels 4.

Backlight unit 2 be from the back side of display panels 4 to the lighting device of whole irradiates light of display panels 4, have light emergence face with the roughly the same shape of the picture display face of display panels 4.

Shown in Figure 1A, Figure 1B, Fig. 2 A and Fig. 2 B, the backlight unit 2 of first embodiment of the invention has: two light sources 12, diffusion barrier 14, polarization separating film 16, the LGP 18 as light conducting member, light mixing 20, reflection thin plate 22.Below, each member of formation that constitutes backlight unit 2 is described.

Light source 12 at first is described.

Shown in Figure 1B, two light sources 12 dispose with the form that clips LGP 18 betwixt.Light source 12 possesses led array 24 and coupled lens 40.Led array 24 is that a plurality of RGB-LED30 that will form with red, green and blue these three kinds of light emitting diodes (below be called R-LED32, G-LED34 and B-LED36) are configured to row and constitute.Fig. 3 schematically shows the configuring condition of a plurality of RGB-LED30.As shown in Figure 3, R-LED32, G-LED34 and B-LED36 dispose regularly.

In addition, as shown in Figure 4, RGB-LED30 is so that the light that sends respectively from R-LED32, G-LED34 and B-LED36, is adjusted the direction of optical axis of three types LED (R-LED32, G-LED34 and B-LED36) in the form that the position of regulation intersects.Like this, by adjusting three types LED, the light of these LED can be carried out colour mixture and send white light.

Since with compare with the cold-cathode tube (CCFL) that light source uses as existing backlight, RGB-LED30 with trichromatic LED (R-LED32, G-LED34 and B-LED36) formation, its color reproduction zone is wide and purity is high, thereby under situation about using as light source with this RGB-LED30, color reproduction becomes than existing backlight light source height, can demonstrate the image of bright-coloured color.

As shown in Figures 3 and 4, the light emitting side at each LED of RGB-LED30 disposes three globe lens 42,44 and 46 as coupled lens. Globe lens 42,44 and 46 corresponding configurations with each LED.That is, there are three globe lens 42,44 and 46 to use for a RGB-LED30 combination.Light from each LED (R-LED32, G-LED34 and B-LED36) sends is become directional light by globe lens 42,44 and 46.Then, intersection becomes white light in the position of regulation, afterwards, injects the mixed portion 20 of light of LGP 18.It is the lens that have three axles that combination has the coupled lens of three globe lens 42,44 and 46 uses, can make the light of RGB-LED focus on a bit and mix.

, used globe lens herein, but be not only to be confined to this, just be not particularly limited as long as the light that LED is sent becomes directional light as coupled lens.Coupled lens for example also can use lens, Fresnel lens of cylindrical lens, biconvex shape, the half-conical bodily form etc.

Below, the LGP 18 of backlight unit 2 is described.

Shown in Fig. 2 A, LGP 18 has: the smooth light emergence face 18a of essentially rectangular shape; Two inclined planes (the first inclined plane 18b and the second inclined plane 18c) that the opposition side that is positioned at light emergence face 18a is parallel with one side of light emergence face 18a, be mutually symmetrical and tilt with the angle of regulation with respect to light emergence face 18a with respect to the bisecting line X of bisection light emergence face 18a; Face, make two light entrance faces (the first light entrance face 18d and the second light entrance face 18e) of injecting from the light of these led array mutually with two led array 24.The first inclined plane 18b and the second inclined plane 18c are the boundary with bisector X and tilt with respect to light emergence face 18a.LGP 18, along with close to central authorities from the first light entrance face 18d and the second light entrance face 18e, thickness is thickening gradually, and central portion is the thickest, and both ends are the thinnest.

Promptly, LGP 18 is a plate-like shape roughly, with the front (face that area big) of light emergence face 18a as plate, with the first light entrance face 18d and the second light entrance face 18e side (the elongated face of thickness direction), with the first inclined plane 18b and the second light entrance face 18c rear side as plate as plate.

The first inclined plane 18b and the second inclined plane 18c are not particularly limited with respect to the angle of light entrance face 18a.

In addition, on the first inclined plane 18b and the second inclined plane 18c, be formed with the prism row along the direction parallel with light entrance face 18d and 18e.Can also substitute this prism row and form the optical element that is similar to prism regularly.For example, also can on the inclined plane of LGP, form the optical element that biconvex lens, concavees lens, convex lens, pyramid type etc. have lens effect.

In the LGP 18 shown in Figure 2, scattering takes place from the scattering object (stating as detailed below) of the light of the first light entrance face 18d and the second light entrance face 18e incident inside by being contained in LGP 18, simultaneously, pass LGP 18 inside, directly or by the first inclined plane 18b and the second inclined plane 18c undertaken penetrating from light emergence face 18a after the reflection.At this moment, though also leak a part of light that looses sometimes from the first inclined plane 18b and the second inclined plane 18c, but, leak the light shed by reflection thin plate (not shown) reflection with the form configuration of the first inclined plane 18b that covers LGP 18 and the second inclined plane 18c, inject the inside of LGP 18 again.

LGP 18 is to mix to be dispersed with to be used to make the scattering particles of light generation scattering to form in transparent resin.Port リ エ チ レ Application テ レ Off タ レ one ト), PP (polypropylene), PC (Merlon), PMMA (polymerthyl acrylate: Port リ メ チ Le メ タ Network リ レ one ト), benzyl olefin(e) acid methyl esters (ベ Application ジ Le メ タ Network リ レ one ト), MS resin or COP (cycloolefine polymer: and so on optical transparent resin シ Network ロ オ レ Off イ Application Port リ マ one) as the material of the transparent resin that is used for LGP 18, for example can enumerate PET (PET:.Be scattered in the scattering particles of LGP 18 as mixing, can use ア ト シ パ one Le, シ Application ユ one Application, silica, zirconia (ジ Le ユ ニ ア), dielectrical polymer etc.Because this scattering particles is contained in the inside of LGP 18, thereby can send evenly and the few illumination light of brightness disproportionation from light emergence face.

This LGP 18 can use extruding formation method and injection molded manufactured.

In addition, long-pending at the scattering section of establishing the scattering particles that is contained in LGP 18 is Φ, the incident direction that is located at light from the light entrance face of LGP to the length of the position of the thickness maximum of the perpendicular direction of light emergence face, 1/2nd the length that in the present embodiment is the light incident direction of establishing LGP (direction perpendicular to the first light entrance face 18d of LGP 18 is called " optical axis direction " below) is L _G, the density (population of per unit volume) of establishing the scattering particles that is contained in LGP 18 is N _P, establishing correction coefficient is K _CThe time, satisfy Φ N _PL _GK _CValue be more than 1.1 and below 8.2, and establish K _CValue be this relation below 0.1 more than 0.005.Because LGP 18 comprises the scattering particles that satisfies this relation, thereby can send even and the less illumination light of irregularity in brightness.

Usually, the transmitance T when making collimated light beam be injected into isotropic medium represents with following formula (1) according to the Lambert-Beer rule.

T＝I/I ₀＝exp(-ρ·x) (1)

Herein, x is a distance, I ₀Be incident intensity, I is for penetrating intensity, and ρ is an attenuation constant.

Above-mentioned attenuation constant ρ uses the long-pending Φ of the scattering section of particle and is contained in the population N of the per unit area of medium _PRepresent by following formula (2).

ρ＝Φ·N _P (2)

Therefore, be L if establish 1/2nd length of the optical axis direction of LGP _G, the taking-up efficient E of light then _OutAvailable following formula (3) is obtained.Herein, 1/2nd length of the optical axis direction of LGP are L _G, be length from a light entrance face of the LGP 18 of the direction vertical to the central authorities of LGP 10 with the light entrance face of LGP 18.

In addition, so-called light takes out efficient, is to leave length L from the plane of incidence arrival of LGP at optical axis direction _GThe light of position with respect to the ratio of incident light, for example, the situation of LGP 18 as shown in Figure 2 is to arrive and ratio at the light of the central authorities of the relative LGP of the light of surface feeding sputtering (being exactly the position of 1/2nd length of the optical axis direction of LGP).

E _out∝exp(-Φ·N _P·L _G) (3)

Herein, formula (3) is the relation in the limited space of size, has quoted the correction coefficient K of the relation that is used for correction and formula (1) _CCorrection coefficient K _CBe that dimension that light is rule of thumb obtained when propagating in the optical medium of the confined space is 1 correction coefficient.Like this, the taking-up efficient E of light _OutRepresent with following formula (4).

E _out＝exp(-Φ·N _P·L _G·K _C) (4)

According to formula (4), at Φ N _PL _GK _CValue be 3.5 o'clock, the taking-up efficient E of light _OutBe 3%, at Φ N _PL _GK _CValue be 4.7 o'clock, the taking-up efficient E of light _OutBe 1%.

This result shows, if Φ N _PL _GK _CValue become big, the taking-up efficient E of light then _OutStep-down.In order to make light scattering take place, can consider to reduce the taking-up efficient E of light along with the optical axis direction of close LGP _Out

Thereby find out Φ N _PL _GK _CValue wonderful works LGP character is good more more.That is, by improving Φ N _PL _GK _CValue, both can reduce the light that penetrates from the face of facing mutually with the plane of incidence of light, can increase again from the light of light emergence face emission.That is, by improving Φ N _PL _GK _CValue, can improve the light that penetrates from light emergence face with respect to the ratio of the light that incides the plane of incidence (below be also referred to as " light utilization ratio ").Particularly, be exactly to pass through with Φ N _PL _GK _CValue be made as more than 1.1, the light utilization ratio is reached more than 50%.

Herein, when improving Φ N _PL _GK _CValue the time, the uneven illumination of the light that penetrates from the light emergence face 18a of LGP 18 becomes obviously, still, by with Φ N _PL _GK _CValue be made as below 8.2, thereby uneven illumination can be controlled at below the constant (in the allowed band).In addition, illumination can be handled with brightness substantially the samely.Therefore, in the present invention, deducibility brightness has the same tendency with illumination.

According to above-mentioned analysis, the Φ N of preferred LGP of the present invention _PL _GK _CValue satisfy 1.1 or more and these relations below 8.2, more preferably more than 2.0 and below 7.0.In addition, further preferred Φ N _PL _GK _CValue be more than 3.0, Φ N most preferably _PL _GK _CValue be more than 4.7.

In addition, preferred correction coefficient K _CBe more than 0.005 below 0.1.

Below, come together to illustrate in greater detail LGP with specific embodiment.

At first, scattering section is amassed Φ, establishes particle density N _P, LGP 1/2nd length L of optical axis direction _G, correction coefficient K _CBe made as various values, for Φ N _PL _GK _CEach different LGP of value, utilize computer simulation to try to achieve the light utilization ratio, also carried out the evaluation of uneven illumination.At this, uneven illumination " % " is for being I in the maximal illumination of establishing the light that penetrates from the light emergence face of LGP _Max, establishing minimal illumination is I _Min, establishing average illumination is I _AvcThe time ((I _Max-I _Min)/I _Avc) * 100.

The result who measures is shown in following table 1.In addition, the judgement of table 1 is, the light utilization ratio is more than 50% and uneven illumination 150% is represented with zero when following, the light utilization ratio less than 50% and uneven illumination greater than usefulness * expression in 150% o'clock.

In addition, Fig. 5 represents to measure Φ N _PL _GK _CValue and the result of the relation of light utilization ratio (with respect to light, the ratio of the light that penetrates from light emergence face) in light entrance face incident.

Table 1

	Φ(m 2)	N P(individual/m 3)	L G (m)	K C	ΦN PL GK C	Light utilization ratio (%)	Uneven illumination (%)	Judge
									Embodiment
1	2.0×10 -12	2.2×10 14	0.3	0.03	3.51	81.6	84	○
									Embodiment 2	2.0×10 -12	4.3×10 14	0.3	0.02	6.21	84.7	149	○
Embodiment 3	2.0×10 -12	8.6×10 14	0.1	0.02	3.86	82.8	82	○
									Embodiment 4	1.1×10 -10	1.5×10 13	0.3	0.008	3.91	83.0	105	○
Embodiment 5	1.1×10 -10	2.0×10 13	0.3	0.007	4.98	84.3	142	○
									Embodiment 6	1.1×10 -10	3.5×10 13	0.1	0.007	2.86	79.2	47	○
Comparative example 1	2.0×10 -12	2.2×10 13	0.3	0.05	0.66	29.1	51	×
									Comparative example 2	1.1×10 -12	2.5×10 12	0.3	0.01	0.99	43.4	59	×
Comparative example 3	4.8×10 -18	8.6×10 17	0.1	15.2	6.26	84.8	201	×
									Comparative example 4	4.8×10 -18	1.7×10 18	0.1	13.9	11.5	84.9	225	×

Table 1 and Fig. 5 show, by with Φ N _PL _GK _CBe made as more than 1.1, can improve the light utilization ratio, particularly the light utilization ratio can be mentioned more than 50% exactly; By being made as below 8.2, uneven illumination can be controlled at below 150%.

Also show in addition, by with K _CCan improve the light utilization ratio thereby be made as more than 0.005, by with K _CThereby be made as the uneven illumination that can reduce below 0.1 from the light of the ejaculation of LGP.

Then, will mix or be scattered in the atomic particle density N of LGP _PBe made into the LGP of various values, measured the Illumination Distribution of the light that penetrates from each position of the light emergence face of each LGP.At this, in the present embodiment, remove particle density N _POutside, with other condition, particularly be exactly with scattering section long-pending Φ, particle density N _P, LGP 1/2nd length L of optical axis direction _G, correction coefficient K _C, LGP shape etc. make identical value.Therefore, with regard to present embodiment, Φ N _PL _GK _CWith particle density N _PProportional variation.

Like this, for the LGP of various particle densities measure respectively the light that penetrates from light emergence face Illumination Distribution the result as shown in Figure 6.Among Fig. 6, the longitudinal axis is made as illumination (lx), transverse axis is made as apart from the distance (leaded light length) of a light entrance face of LGP (mm).

The big illumination of doing of the light that will penetrate from the sidewall of the LGP of the Illumination Distribution measured is made as I again _Max, minimal illumination is made as I _Min, will establish average illumination and be made as I _AvcThe time, calculated uneven illumination ((I _Max-I _Min)/I _Avc) * 100.

Fig. 7 represents the uneven illumination that calculates and the relation of particle density.Among Fig. 7, the longitudinal axis is uneven illumination (%), and transverse axis is that particle density is (individual/m ³).In addition, in Fig. 7, represent in the lump that also the longitudinal axis is similarly particle density, transverse axis is the light utilization ratio of light utilization ratio (%) and the relation of particle density.

As Fig. 6, shown in Figure 7, promptly improve Φ N if improve particle density _PL _GK _C, then the light utilization ratio uprises, but uneven illumination also becomes greatly, in addition, if reduce particle density, promptly reduces Φ N _PL _GK _C, light utilization ratio step-down then, but uneven illumination diminishes.

At this, by with Φ N _PL _GK _CBe made as more than 1.1 below 8.2, thereby the light utilization ratio is reached more than 50%, and can make uneven illumination below 150%.Because making uneven illumination is below 150%, thereby can make uneven illumination not obvious.

That is, can find out, by with Φ N _PL _GK _CBe made as more than 1.1 below 8.2, thus not only can make the light utilization ratio reach certain more than, but also can reduce uneven illumination.

At this, preferably make the first light entrance face 18d as light entrance face, the second light entrance face 18e, light emergence face 18a of LGP 18, as the surface roughness Ra of at least one face of the first inclined plane 18b, the second inclined plane 18c of light reflection surface less than 380nm, promptly preferred Ra＜380nm.

By making surface roughness Ra as the first light entrance face 18d, the second light entrance face 18e of light entrance face less than 380nm, can ignore the diffuse reflection on LGP surface, diffuse reflection can be prevented, and then incident efficient can be improved at the LGP face.

In addition, the surface roughness Ra by making light emergence face 18a can be ignored the diffuse reflection transmission on LGP surface less than 380nm, can prevent the diffuse reflection transmission on the LGP surface, and then can prevent to be transmitted to the depths because of total reflection makes light.

And then, by making surface roughness as the first inclined plane 18b, the second inclined plane 18c of light reflection surface, can ignore diffuse reflection less than 380nm, can prevent diffuse reflection, and then can make the total reflection composition be transmitted to more depths at light reflection surface.

At this, preferably the thickness (light incident section thickness) at the LGP of establishing light entrance face is D1, and the thickness (central thickness) of LGP that is located at the face of an opposite side with light entrance face is D2, and the length (leaded light is long) of establishing the light incident direction of LGP is during for L, LGP satisfies following relation, promptly

D1＜D2, and

27/100000＜(D2-D1)/(L/2)＜5/100(A)，

Ratio with respect to the weight of the scattering particles of the mixing of the weight of LGP: the scope of Npa is 0.04%Wt＜Npa＜0.25%Wt.

By making the shape that satisfies above-mentioned relation, can improve more than 30% with penetrating efficient.

Perhaps, more preferably to satisfy following relation, promptly

D1＜D2, and

66/100000＜(D2-D1)/(L/2)＜26/1000(B)，

The weight of the scattering particles of sneaking into is 0.04%Wt＜Npa＜0.25%Wt with respect to the scope of the ratio of the weight of LGP: Npa.

Form improve LGP.By making the shape that satisfies above-mentioned relation, can improve more than 40% with penetrating efficient.

In addition, be preferably, to satisfy following relation, promptly

D1＜D2, and

1/1000＜(D2-D1)/(L/2)＜26/1000(C)，

The weight of the scattering particles of sneaking into is 0.04%Wt＜Npa＜0.25%Wt with respect to the scope of the ratio of the weight of LGP: Npa.

Form improve LGP.By making the shape that satisfies above-mentioned relation, can improve more than 50% with penetrating efficient.

Fig. 8 represents the mutually different LGP in the inclination angle on inclined plane, promptly (D2-D1)/(L/2) mutually different LGP has been measured the result of light utilization ratio respectively.At this, the transverse axis of Fig. 8 is (D2-D1)/(L/2) of LGP, and the longitudinal axis is light utilization ratio (%).

Also show from measurement result shown in Figure 8, by the shape of LGP is made 27/100000＜(D2-D1)/(L/2)＜5/100, can make light utilization efficiency is more than 30%, by making 66/100000＜(D2-D1)/(L/2)＜26/1000, can make the light utilization ratio is more than 40%, by making 1/1000＜(D2-D1)/(L/2)＜26/1000, can make the light utilization ratio is more than 50%.

At this, in the present embodiment, for reverberation effectively the prism row are formed at two inclined planes (the first inclined plane 18b and the second inclined plane 18c) of LGP 18, but also may not be necessary to form, also can make and not form fine concavo-convex smooth face.

In addition, in the present embodiment, LGP is become, make the face faced mutually with light emergence face inclined plane and shape with respect to light emergence face inclination certain angle, but, the present invention only is confined to this, as long as the thickness of the LGP of the face of facing mutually with light entrance face is the thick shape of thickness than the LGP of light entrance face, just can be shape arbitrarily.For example, also can will make curve form with the face (the first inclined plane 18b of Fig. 1 and Fig. 2 and/or the second inclined plane 18c) that the light emergence face of LGP is faced mutually.In addition, the inclined plane is being made under the situation of curved surface, both can make protruding shape, also can make recessed shape at light emergence face in the light emergence face side.

Below, one of the preferred shape example of LGP is described in conjunction with Fig. 9.

Fig. 9 A～Fig. 9 D is a summary section of representing an other routine LGP respectively.Figure 10 A is the summary section of the other routine LGP of expression, and the connecting portion periphery on each inclined plane of the LGP that Figure 10 B will be shown in Figure 10 A has carried out amplifying the summary section of expression.

LGP 202 shown in Fig. 9 A, its first inclined plane 204 is made of first rake 206 of light entrance face 18d side and second rake 208 of LGP center side.First rake 206 and second rake 208 tilt with respect to the angle that the inclination angle of light entrance face differs from one another with it, compare with the inclination angle of first rake 206, and this square degree of the inclination angle of second rake 208 is little.That is, first inclined plane is formed by the rake that becomes mild along with the central inclination angle of close nearly LGP.

In addition, second inclined plane 204 ' is the shape with first inclined plane, 204 symmetries, becomes by first rake 206 ' of the second light entrance face 18e side with at LGP center side inclination angle to constitute than first rake, 206 ' the second mild rake 208 '.

Like this, by the cross sectional shape on inclined plane being made the shape that constitutes by the different a plurality of straight lines in inclination angle, make the inclination angle shape bigger of the rake of light entrance face side, can prevent to improve brightness near the light of the part ejaculation light entrance face of light entrance face than the inclination angle of the rake of center side.Thus, more uniform light is penetrated from light emergence face.

In addition, among Fig. 9 A, constituted the inclined plane with two rakes, still, there is no particular restriction for the number of the rake on formation inclined plane, also can be made of the rake of the arbitrary number that disposes with the form that becomes mild gradually along with the central inclination angle near LGP.

For example, shown in Fig. 9 B, also can constitute first inclined plane 212 (second inclined plane 212 ') of LGP 210 with three rakes, these three rakes are second rake 218 (218 ') that second rake 216 (216 ') that first rake 214 (214 '), inclination angle become mild than first rake 214 (214 '), inclination angle become mild than second rake 216 (216 ') from the first light entrance face 18d (the second light entrance face 18e) side respectively near LGP central authorities.

Secondly, the LGP 220 shown in Fig. 9 C is in the first light entrance face 18d side on first inclined plane 222, promptly have a curved face part 222a of R shape at the connecting portion with the first light entrance face 18d.In addition, second inclined plane 222 ' is too at the curved face part 222a ' that has the R shape with the second light entrance face 18e side.

Like this, by curved face part being set and making the R shape at connecting portion with the light entrance face on the inclined plane of LGP, light entrance face and inclined plane are made the shape of smooth connection, also can prevent the situation that uprises near the brightness of the light that penetrates the light entrance face of outgoing plane.

Secondly, the LGP 230 shown in Fig. 9 D is formed at the aspherical shape that available 10 power multinomials are represented first inclined plane 232 and second inclined plane 232 '.

Like this, by aspherical shape is made on the inclined plane, also can prevent the situation that uprises near the brightness of the light that penetrates the light entrance face of outgoing plane.

And then shown in Figure 10 A and Figure 10 B, preferably first inclined plane 60b of LGP 60 and the connecting portion 60f (central portion on the inclined plane of LGP) of the second inclined plane 60c are made curve form or R shape, and it is connected smoothly.Thus, the connecting portion 60f that can prevent at the first inclined plane 60b and the second inclined plane 60c produces bright line, concealed wire etc., and then can send more uniform light.

At this, at the connecting portion of each inclined plane 60b, 60c of LGP 60, promptly the central portion of LGP 60 is being made under the situation of R shape, if the radius of curvature of its R shape is made as R ₁, preferred curvature radius R then ₁And the relation between the length L of the light incident direction of LGP satisfies 3L≤R ₁≤ 500L.

In addition, be L in the length of establishing from end to the end of the R shape of the connecting portion 60f of light incident direction _R, establish the angle that forms by face that is parallel to light entrance face 60a and the first inclined plane 60b (the perhaps second inclined plane 60c) when being θ, preferably satisfy 2R ₁Sin (θ)≤L _R

By setting L _RBe 2R ₁More than the sin (θ), can suppress the reduction of the brightness of central portion, and can penetrate more uniform light from light emergence face.

In addition, be preferably, LGP is the shape that satisfies following formula: i.e. 3L≤R ₁≤ 500L, and 2R ₁Sin (θ)≤L _R≤ 0.98L.

In addition, use the maximum ga(u)ge t of LGP 60 _Max, minimum thickness t _MinAnd the length L of the incident direction of the light of LGP, can be used as following formula (D) and represent θ.

(several 1)

$\mathrm{\&theta;}={\tan }^{-1}\left[\frac{t_{\max }-t_{\min }}{L/2}\right]---\left(D\right)$

In addition, also can in above-mentioned transparent resin, sneak into plasticizer and make LGP.

Like this,, can flexiblely form LGP, can form LGP, and then can make LGP be deformed into different shape with flexibility by making LGP with the material that has mixed transparent material and plasticizer.Therefore, can on various curved surfaces, form the surface of LGP.

Thus, for example with LGP, perhaps used under the situation of planar illuminating device as the display board use of lamp decoration (illumination) relation of this LGP, LGP is installed on the wall that has curvature knot and LGP can be applied to the lamp decoration of more kind, the more wide scope of application and POP (POP advertisement) etc.

At this, can list phthalic acid (acid of Off タ Le) ester as plasticizer, Off タ Le acid ジ メ チ Le), diethyl phthalate (DEP), dibutyl phthalate (DBP), dioctyl phthalate (DOP (DEHP)), phthalic acid two positive esters (DnOP), phthalic acid ester in the different ninth of the ten Heavenly Stems (DINP), diisononyl phthalate (DNP), phthalic acid isodecyl ester (DIDP), phthalic acid mixed base ester (C particularly, can enumerate rutgers (DMP: ₆～C ₁₁) (610P, 711P etc.), butyl phthalate benzene methyl (BBP).In addition, except that titanate esters, also can enumerate ethanedioic acid dioctyl ester (DOA), diisononyl adipate (DINA), ethanedioic acid nalka ester (C _6,8,10) (610A), ethanedioic acid alkane ester (C _7,9) (79A), dioctyl azelate (DOZ), dibutyl sebacate (DBS), di-n-octyl sebacate (DOS), tricresyl phosphate (TCP), tributyl 2-acetylcitrate (ATBC), epoxidised soybean oil (ESBO), trioctyl trimellate (TOTM), polyester system, chlorinated paraffin wax etc.

As shown in Figures 1 and 2, in the backlight unit 2 of present embodiment, light mixing 20A and 20B are set with two side driving fits of LGP 18.Light mixing 20A and 20B are the optical components of having sneaked into the column of the particle that makes light scattering in transparent resin, have the function that the light by coupled lens 40 is mixed.With regard to the material of light mixing 20A and 20B, can use basically and LGP 18 identical materials, the same with LGP 18, can comprise and be used to make the scattering object of light in inside generation scattering.The density etc. of scattering object that is contained in the inside of light mixing 20A and 20B both can be identical with LGP 18, also can be different with LGP 18.In addition, as shown in Figure 2,, preferably use the high material of hear resistance to form light mixing 20A and 20B in order to be close to the led array configuration.

Below, polarization separating film 16 is described.

In the present embodiment, as preferred mode, be on the light emergence face 18a at the face of the light emitting side of LGP 18, polarization separating film and LGP are formed integrally formed LGP 18.Polarization separating film 16 can make the polarized component of regulation that the p polarized component is passed the light that penetrates from the light emergence face of LGP selectively, and make in addition polarized component for example the overwhelming majority of s polarized component reflect.Polarization separating film 16 be owing to can make the light that has carried out reflection inject LGP once more and utilize, thereby, can improve light utilization ratio, brightness is significantly improved.

Polarization separating film 16 for example by the board-like material that acicular particles is blended in transparent resin and disperses to obtain is extended, and makes acicular particles directed and obtain in the direction of regulation.

Preferably when the manufacturing of LGP 18, pressure welding or heat bonding polarization separating film 16 also form one.Like this, can make between the light emergence face 18a of LGP 18 and the polarization separating film 16 not air entrainment, and make driving fit each other.

At this, polarization separating film 16 and LGP 18 are formed, but be not only to be confined to this, also can distinguish and make polarization separating film 16 and LGP 18 separately, again polarization separating film 16 is pasted on the face of the light emergence face side of LGP 18.

In addition, with regard to illustrated example, though polarization separating film 16 is arranged at LGP 18 light emergence face directly over, be not only to be confined to this, also can be arranged on the diffusion barrier.This situation also can form as one polarization separating film and diffusion barrier.

In addition, can use material known as polarization separating film 16.

For example, also can use as the spy open that flat 6-331824 communique is put down in writing, on the light emergence face of LGP, have the refractive index higher at least one plane of polarization than the refractive index of LGP, have the birefringence material of the refractive index lower than the mean refractive index of LGP for the plane of polarization vertical with this plane of polarization.

In addition, also can use the extension film of opening flat 11-281975 communique record as the spy.At this, open the record of flat 11-281975 communique as the spy, the situation of using extension film preferably is pasted on the single face of LGP across adhering agent layer or adhesive layer.

In addition, also can use as the spy and open flat No. 49496 communique multi-layer tectosomes that put down in writing, that big transparent medium of relative index of refraction and the little transparent medium interaction cascading of relative index of refraction are formed, and on single at least of planar transparent supporting body, the preferred material that forms the dielectric film that only has the following thickness of 1000nm more than one deck at least perhaps uses the material that is laminated with the different polytype transparent polymer of refractive index.

In addition, can also use the dielectric film that has more than one deck with the equal following thickness of visible wavelength as spy's on the cross section roughly is the transparent supporter of W font, being provided with at least of opening that flat 7-72475 communique put down in writing to constitute, make the p polarized component see through, make at least a portion of s polarized component that the polarization separator that reflects takes place near the light the incident direction of regulation.

In addition, also can use as the spy and open the recurrence polarization by reflection body that the 2004-78234 communique is put down in writing, this recurrence polarization by reflection body, have and be arranged side by side, arrange the structure surface that constitutes by the linearity of the prism of the two equilateral coefficients at right angle in fact, it constitutes, first material of face that has the Vertical factor of the angles that roughly form 45 degree for contact-making surface towards the opposite level and smooth surface of this structured surface, second identical with the first material in fact material, and be positioned on the structure plane of at least a material, and constitute by the high-index material of selected optical thickness and layer at least a optical accumulation that constitutes of low-index material intermeshing, first and second material all is optical joint, form single institution, in this single institution, a plurality of layers the above-mentioned refractive index of the refractive index of first and second material and above-mentioned optical accumulation and the selection of optical thickness, all to carry out for the selective reflecting that generates the light after being polarized, the inside of a part of piling up at above-mentioned optics, the incident ray of mixed polarization is separated into s-polarized component and p-polarized component, the other parts that above-mentioned s-polarized component is piled up by above-mentioned optics reflect, it is parallel with incident ray by this partial reflection one-tenth, but propagate along the direction opposite with incident light, above-mentioned p-polarized component passes abreast with respect to incident ray.

In addition, also can use as the spy and open the polarizer that clear 61-262705 communique is put down in writing, described polarizer is, on the transparent material after forming the triangular waveform face, the dielectric body multilayer film with polarizing filter function and polarizer function is set at the groove of raised line that the A type is set alternately and V-type.

In addition, also can use as No. 3610729 specification of United States Patent (USP) put down in writing, will possess the material that birefringence is arranged make again carry out continuously on the floor of 1/4 thickness of wavelength stacked.

In addition, also can use as the United States Patent (USP) optical thin film that No. 5867316 the communique specification is put down in writing, it is by having the continuous phase that possesses birefringence and forming at the polymer of a spot of decentralized photo in the inside of continuous phase.

In addition, also can use as the spy and open the polarization separating film of 2003-295183 communique putting down in writing, described polarization separating film is the formation of the metallic film that has utilized surface plasma (プ ラ ズ モ Application) having been carried out layering with the low-refraction transparent medium.

And then, on the basis of the configuration that has utilized the polarization film that only makes the P polarized component that is parallel to the plane of incidence pass, make the surface plasma that reflects perpendicular to the S polarized component generation of the plane of incidence, that the polarisation of light direction changes with making, for example by will between perpendicular polarized component, in optical thickness, having polarization direction change films such as λ difference, that have birefringence/4 phase films that only produce λ/4 and diffusion barrier, form one with LGP and constitute, thus, can further improve brightness.

In addition, also can use as what the spy opened that flat 8-76114 communique puts down in writing extends liquid crystal and high molecular complex and the scatter-type polarizing coating of the anisotropic scattering object that forms, be used for substituting of offset separation film 16, perhaps to as the special axle of opening the molecular spiral that flat 6-281814 communique put down in writing carry out orientation with the form that the crosscut film extends, the spacing that makes the molecular spiral of film is reached the cholesteric polarization film that the mode of 100nm changes at least with the difference between maximum spacing and the minimum spacing uses as polarization separating film 16.

In addition, also can use and open direction of vibration that the 2001-343612 communique is put down in writing, by the straight line polarization as the spy and make the different noise anisotropic band of noise figure.Preferred this situation is pasted first phase-plate at the face opposite with the light emergence face of LGP again, and between LGP and reflecting plate second phase-plate is set.

In addition, can use as the spy and open the polarizer that flat 9-274108 communique is put down in writing, described polarizer is dispersed with the tiny area that is made of different therewith materials with quality among transparent macromolecule membrane, make for basic identical with a side's of the perpendicular rectilinearly polarized light of macromolecule membrane and tiny area refractive index, and for the opposing party's of this rectilinearly polarized light refractive index difference.

In the above-mentioned embodiment, though the light emergence face side that polarization separating film is arranged at LGP 18 has realized the raising of brightness, but, even substitute polarization separating film is set, open 2001-201746 communique, spy open as described in the 2001-228476 communique as the spy, light emergence face at LGP forms the micro concavo-convex portion with polarization separation function, also can improve from the brightness of the light of light emergence face ejaculation.

In addition, substitute polarization separating film 16, open as described in the flat 9-134607 communique as the spy, between LGP and reflecting member (reflecting plate), configuration have in fact the first above refractive index of the refractive index of LGP and and little second refractive index of the refractive index of LGP, with the anisotropic band that roughly all is separated with second polarization state of first polarization state perpendicular to first polarization state, also can improve brightness.

In addition, open as described in the 2004-363062 communique, form the coarse patterns that constitutes by micro crowning, also can improve brightness with polarization separation function in the inclined backside of LGP as the spy.

In addition, show as described in the flat 10-508151 communique as the spy, go up the recess that setting is filled with the material different with the material in optical guided wave path at optical guided wave path (LGP), make a wherein side of these two kinds of materials become the isotropic material that refractive index is np, make the opposing party become the anisotropic material that refractive index is no and ne.At this, about refractive index, no or ne equal np, perhaps in fact equate.Thus, polarization is separated at the interface between available isotropic material and the anisotropic material, before can penetrating along the optical guided wave path in the overwhelming majority of the light that is irradiated by light source, becomes the light with identical polarization direction.Like this, be applied to the present invention, also can improve brightness even the spy is shown the described formation of flat 10-508151 communique.

In addition, open as described in the flat 9-292530 communique as the spy, constitute LGP with two-layer above layer with light-guiding function, one deck at least of the ground floor or the second layer is made the material with birefringence, between the ground floor and the second layer, the interface is set, make and penetrate light after scattering or refraction or diffraction have taken place interface light, also can improve brightness from the surface of LGP.

Below, the reflection thin plate 22 of backlight unit is described.

Reflection thin plate 22 is that a kind of light that looses from inclined plane 18c, the 18d leakage of LGP 18 that makes reflects, and injects the device of LGP again, can improve the utilization ratio of light.Reflection thin plate 22 is bent and forms at central portion with the inclined plane 18c that covers LGP 18 respectively and the form of 18d.

Reflection thin plate 22 is so long as can make the light generation reflection of loosing from inclined plane 18c, the 18d leakage of LGP 18 get final product, can enough any materials form, Port リ プ ロ ピ レ Application) etc. for example: by at PET and PP (polypropylene: extend after sneaking into filler, and form the space and the resin sheet or the surface of having improved the resin sheet of reflectivity, formed the metal forming such as thin plate, aluminium of minute surface on the surface of transparent or white resin thin plate by AM aluminum metallization etc. or having served as metal forming form by having enough reflexive sheet metals.

Below, diffusion barrier 14 is described.

As shown in Figure 1, diffusion barrier 14 is disposed between polarization separating film 16 and the display panels 4, and diffusion barrier 14 has light scattering and is formed at film shape member.Port リ メ チ Le メ タ Network リ レ one ト), the optically transparent resin of benzyl olefin(e) acid methyl esters (ベ Application ジ Le メ タ Network リ レ one ト), MS resin or COP (cycloolefine polymer) and so on film shape member for example can form PET (PET), PP (polypropylene), PC (Merlon), PMMA (polymerthyl acrylate: in material.

There is no particular restriction for the manufacture method of diffusion barrier 14, for example can make surface roughening have diffusivity by enforcement microfabrication and grinding on film shape member, perhaps will make light that the pigment such as silica, titanium oxide, zinc oxide of scattering take place on the surface, and hollow bead classes such as resin, glass, zirconia apply with adhesive, perhaps above-mentioned pigment and hollow bead class are sneaked in the above-mentioned transparent resin and form.In addition, can also be by the absorptivity of reflectivity Gao Guang low material for example uses the metal of Ag, Al and so on and forms.

In the present invention, can use the diffusion barrier of rough type and coating type as diffusion barrier.

The distance that diffusion barrier 14 also can leave the light emergence face regulation of LGP 18 disposes, and its distance can be taken the circumstances into consideration change according to the light quantity distribution from the light emergence face of LGP 18.

Like this, leave the distance of the light emergence face regulation of LGP 18, make the light that penetrates from the light emergence face of LGP 18 between light emergence face and diffusion barrier 14, mix (mixing) again by making diffusion barrier 14.Thus, can make and pass diffusion barrier 14 and the further homogenising of brightness of the light of display panels illumination.

As making diffusion barrier 14 leave the method for distance of the light emergence face regulation of LGP 18, for example can use the method that dividing plate is set between diffusion barrier 14 and LGP 18.

Above, each inscape of the backlight unit 2 of first embodiment of the present invention is had been described in detail, but the present invention only is confined to this.

In the above-mentioned real-time mode, use LED32,34,36 red, green and blue these three kinds of colors, the light that utilizes coupled lens 40 that each LED is sent carries out colour mixture and has obtained white light, but the present invention only is confined to this.The monochromatic LED that with regard to light source, also can use fluorescent material to constitute with the form of using the light that LED is sent to be converted to white light.For example, be under the situation of blue led used CaN as monochromatic LED, be that fluorescent material just can obtain white light as long as use YAG (yttrium, aluminium, garnet).

If utilize the light source that can obtain this white light, then needn't use lens can subdue the number of member.

Figure 11 A is the outline elevation of an embodiment that the expression light source has used the planar illuminating device (backlight unit) of monochromatic LED, and Figure 11 B is the summary section of planar illuminating device.

And the backlight unit 120 shown in Figure 11 A and B, other formation is identical with backlight unit shown in Figure 12 except that light source 122.Therefore, both have been added identical symbol on identical inscape, and its detailed description is omitted, below, the special feature of backlight unit 120 is described.

Light source 122 possesses led array 124 and coupled lens 126, shown in Figure 11 A, faces mutually and disposes with the first light entrance face 18d and the second light entrance face 18e of LGP 18.

A plurality of led chips 128 of led array 124 keep predetermined distance to be disposed on heat sink 130 along row.Figure 12 A represents the approximate three-dimensional map of the formation of led array 124, and Figure 12 B represents the outline elevation of the formation of led chip 128, and Figure 12 C represents the outline elevation of the formation of multilayer LED array 132, and Fig. 3 D represents the summary side elevation of an embodiment of heat sink 25.

Led chip 128 is so that the light that LED is sent with above-mentioned fluorescent material is converted to the LED of the monochrome that the form of white light constitutes.

Heat sink 130 is the tabular components that parallel with one side of LGP 18, faces mutually and disposes with LGP 18.Heat sink 130 a plurality of led chips 128 with the face upper support that LGP 18 is faced mutually.The metal that heat conductivities such as heat sink 130 usefulness copper and aluminium are good constitutes, and absorption is from the hot of led chip 128 generations and be discharged into the outside.

In addition, as present embodiment, be preferably, heat sink 130, in length, be the long shape of length than the short side direction of the face of facing mutually with first light entrance face and second light entrance face of LGP 18 perpendicular to the direction of the face of facing mutually with first light entrance face and second light entrance face of LGP 18.Thus, can improve the cooling effect of led chip 128.

At this, preferably increase heat sink surface area.For example shown in Figure 12 D, heat sink 130 also can be made of with a plurality of fin 130b that are connected with pedestal part 130a the pedestal part 130a that supports led chip 128.

Long-pending, and can improve radiating effect by but a plurality of fin 130b enlarged surface are set.Thus, can improve the cooling effectiveness of led chip 128.

In addition, heat sink is not only to be confined to the air cooling mode, also can use water-cooling pattern.

In addition, in the present embodiment, though used heat sinkly as the support portion of led chip, the present invention only is confined to this, when not needing the cooling of led chip, also can use as the support portion with the tabular component that does not possess heat sinking function.

At this, shown in Figure 12 B, the led chip 128 of present embodiment has the rectangular shape shorter than the length of the orientation of led chip 128 with the length of the perpendicular direction of orientation, that is, the thickness direction (perpendicular to the direction of light emergence face 18a) that has with LGP 18 is the rectangular shape of minor face.In other words, be exactly being shaped as of led chip 128, be a in the length of establishing perpendicular to the direction of the light emergence face 18a of LGP 18, when the length of establishing orientation is b, b＞a.In addition, be p, then p＞b if establish the configuration space of led chip 128.Like this, be preferably perpendicular to the length a of direction of the light emergence face 18a of LGP 18, the length b of orientation, the relation of the configuration space p of led chip 128 satisfies p＞b＞a.

By led chip 128 is made rectangular shape, can keep the output of big light quantity, simultaneously, can make slim light source.By light source is made slimming, planar illuminating device can be made slim.

And led chip is owing to can make led array thinner, thereby, the thickness direction of preferably making with LGP is the rectangular shape of minor face, but, the present invention only is confined to this, but can use the led chip of different shapes such as square shape, round-shaped, polygonal shape, elliptical shape.

In addition, in the present embodiment, led array has been made individual layer, but the present invention only is confined to this, shown in Figure 12 C, can also uses as light source with the multilayer LED array 132 of the formation that is laminated with multilayer LED array 124.Like this, even during stacked LED, by with the led chip be rectangular shape and led array is made slim, also can stacked more led array.By the led array of stacked multilayer, promptly by improving the pack completeness of led array (led chip), exportable bigger light quantity.In addition, the led chip of the led chip of led array and the led array of adjacent layer is also with above-mentioned the same, and preferred disposition satisfies following formula at interval.That is, preferably make the led chip of the led array of the led chip of led array and adjacent layer keep predetermined distance stacked.

As shown in Figure 3, the light emitting side at each led chip 128 of led array 124 disposes globe lens as coupled lens 126.Coupled lens 126 and the corresponding one by one configuration of each led chip 128.The light that penetrates from each led chip 128 becomes directional light through coupled lens 126, incides the light mixing 20 of LGP 18.

At this, used globe lens as coupled lens, but be not only to be confined to this, so long as becoming directional light, the light that LED can be sent just can use various members.With regard to coupled lens, also can use cylindrical lens, biconvex shape lens (レ Application チ キ ユ ラ), semi-conical (か ま Pot こ) lens, Fresnel Lenses etc.

In addition, also can not form configuration led array 24, and be to use photoconductive tube that the light that each LED of led array 24 sends is imported LGP to face mutually with first light entrance face and second light entrance face of LGP 18.The guide path that photoconductive tube available fiber and transparent resin are formed through etc. formation.

Using led array 24 as light source, and this led array 24 is being disposed under near the side of LGP 18 the situation, may make LGP 18 distortion, fusion because of the heating of each LED of constituting led array 24.Therefore, by led array 24 being disposed at the position of the side of leaving LGP 18, use photoconduction (light guide) that the light that LED sends is imported LGP 18, can prevent the distortion and the fusion of the LGP 18 that the heating because of LED causes.

In addition, as an other example of the light source that has used LED, also can use the light source that the red green fluorophor has been installed on blue led.Particularly, also can use to have installed and open the LED that the 2005-228996 communique put down in writing and the light-emitting component of fluorophor as the spy.

In addition, also can use the light source that red, green, blue fluorophor has been installed on infrared LED.Can use as this light source: combination as the special light-emitting device of opening described LED of 2000-347691 communique and fluorophor have been installed, the white light-emitting diode of opening described LED of 2002-43633 communique and fluorophor as the spy has been installed; The light-emitting device of opening described LED of 2005-126577 communique and fluorophor as the spy has been installed.

In addition, the present invention only is confined to fluorophor is disposed at the light-emitting area of LED and sends white light, and can be used as the substituting of light-emitting area that fluorophor is disposed at LED, penetrates white light by fluorophor is sneaked into LGP from light emergence face.

In addition, also can use following formation, that is, replace the light-emitting area that fluorophor is disposed at LED, perhaps apply fluorophor on this basis, perhaps the optical sheet of sneaking into is disposed on the light emergence face of LGP.Also can send white light as above-mentioned formation from light emergence face.

In addition, in the above-mentioned embodiment, though the heat sink writing board shape made from led array, rear side at led chip is configured with the form of extending along the direction parallel with light emergence face, but also can be with the heat sink shape of making bending, for example make L font shape, promptly to be configured to the inclined plane of LGP side to the form that the rear side of reflecting member is extended in rear side from led chip.Thus, can reduce the area of the direction that parallels with the light emergence face of planar illuminating device.

In addition, with heat sink when making crooked shape and being disposed at the inclined plane side of LGP, the degree that preferred heat sink thickness and/or length are made the thickness that does not influence backlight unit.By making thinlyyer than the maximum ga(u)ge and the minimum thickness of LGP with heat sink, be disposed at the rear side on inclined plane, the inclined plane of LGP and the space between the housing can be effectively utilized, and then the thickness attenuation of planar illuminating device can be made.

In addition,, the high material of heat conductivity be can use, metal, other various materials such as aluminium, copper for example used as mentioned above as heat sink material.

In addition, housings preferred heat sink and from outside supporting LGP, reflecting member, led array etc. keep the heat conduction to be connected.That is, preferred heat sink the conduction with housing maintenance heat is connected.Heat sinkly be connected by making, the heat that produces from led chip is dispelled the heat in backlight unit (planar illuminating device) integral body with the housing heat conductivity.

Thus, heat is dispelled the heat effectively.

At this, heat sinkly be not limited only to directly contact with housing, also can contact by the thermally coupled body.

In addition, in the above-mentioned embodiment, made following structure, promptly on the first inclined plane 18b of LGP 18 and the second inclined plane 18c, be formed with the prism row, but, on the first inclined plane 18b of LGP 18 and the second inclined plane 18c, do not form the prism row, but configuration is formed with the prism thin plate of prism row on the light emergence face 18a of LGP 18, also can obtain same effect.The formation of the backlight unit when Figure 13 schematically illustrates the light emergence face 18a that prism thin plate 26 is disposed at LGP 18 and goes up.In the illustrated example, LGP 18, polarization separating film 16 and prism thin plate 26 are formed as one.At this, LGP 18, polarization separating film 16 and prism thin plate 26 are formed as one, but also they can be configured as independent member.

Prism thin plate 26 is the transparent thin boards that form by a plurality of prisms are arranged in parallel, thereby the light harvesting that can improve the light that penetrates from the light emergence face of LGP 18 improves brightness.

As the method that LGP 18, polarization separating film 16 and prism thin plate 26 are formed as one, for example at first make and make polarization separating film 16 and prism thin plate 26 incorporate thin plates, then as long as when the manufacturing of LGP 18, make this thin plate and LGP 18 heat bondings or crimping form one.

As making polarization separating film 16 and prism thin plate 26 form the method for one, can use the method that prism thin plate 26 and polarization separating film 16 are made separately, simply pasted, and polarization separation sheet material material dropped into mould (type) roll of continuous extruder, again with the method for the prism thin plate heat bonding that squeezes out.But, be not only to be confined to these methods.

In addition, also configuration prism thin plate can possessed between the polarization separating film 16 and scattering thin plate 14 that makes prism be listed as backlight unit LGP 18, as shown in Figure 1 that is formed at the first inclined plane 18b and the second inclined plane 18c.

In the example as shown in figure 13, constitute, but also can constitute with two prism thin plates by a slice prism thin plate.Under this situation, a slice in two prism thin plates disposes with the mode that the light entrance face (the first light entrance face 18d and the second light entrance face 18e) of LGP 18 parallels with the bearing of trend of these prism row, and another sheet disposes to become vertical form with respect to it.That is two prism thin plates form configuration of becoming to be perpendicular to one another with the orientation of prism row.

In addition, preferably these prism thin plates with the form configuration of the drift angle of its prism towards polarization separating film 16 sides.

And under the situation of two prism thin plates of configuration, the configuration sequence of prism thin plate does not have special restriction.Promptly, can be directly over polarization separating film 16, dispose the prism thin plate that has along the prism of the direction extension parallel with the light entrance face of LGP 18, on this prism thin plate, dispose the prism that has along the direction extension vertical, otherwise also can with the light entrance face of LGP 18.

In addition, in the illustrated example, used prism thin plate 26, but also can replace the prism thin plate and use the thin plate that has disposed the optical element that is similar to prism regularly.For example, also can use and dispose biconvex lens, concavees lens, convex lens, pyramid (pyramid) shape etc. regularly and have the thin plate of the optical element of lens effect, substitute the prism thin plate.

In addition, also can not use the prism thin plate and use the multi-disc diffusion barrier.The use sheet number of diffusion barrier is generally more than two, and is preferred more than three.

And then, also can be as shown in figure 14, the first inclined plane 18b and the second inclined plane 18c at LGP 18, pattern particularly is exactly that promptly the density of the first light entrance face 18d side and the second light entrance face 18e side is low according to the end of LGP 18 in accordance with regulations, along with from the first light entrance face side 18d and the second light entrance face side 18e to the pattern that the central authorities of LGP 18 uprise gradually near density, for example form a plurality of diffuse reflectors 140 by printing.By pattern in accordance with regulations this diffuse reflector 120 is formed at the inclined plane face 18b of LGP 18, the light emergence face 18a that can be suppressed at LGP 18 produces bright line and inequality.

In addition, also can replace the first inclined plane 18b and the second inclined plane 18c that diffuse reflector 140 are printed in LGP 18, and will be in accordance with regulations the pattern thin plate that is formed with diffuse reflector 140 be disposed at the first inclined plane 18b of LGP 18 and the second inclined plane 18c and reflect between the thin plate 22.And the shape of diffuse reflector 140 can be made shape arbitrarily such as rectangle, polygon, circle, ellipse.

At this, as diffuse reflector, for example also can be to be coated with the pigment such as silica, titanium oxide or zinc oxide that make light generation scattering with adhesive, the perhaps material of material that is used to make light generation scattering of resin, glass or zirconia class, and surface is because of micro concavo-convex processing and grind the surface roughening pattern that forms.In addition, also can be reflectivity height, the low material of light absorption, for example use the metal of Ag, Al and so on.In addition, also can use the common chalk that is used by screen painting, hectographic printing etc. as diffuse reflector.As an example, can use that titanium oxide, zinc oxide, zinc sulfate, barium sulfate etc. are scattered in acrylic adhesive and polyester is printing ink after in adhesive, the vinyl chloride adhesive etc., or in titanium oxide, be mixed with silica and have the printing ink of scattering.

In addition, in the present embodiment, diffuse reflector has been made along with leaving light entrance face from dense to sparse, but the present invention only is confined to this, select but can wait as one sees fit according to the Luminance Distribution of the intensity of brightness line and width, required ejaculation light, for example, both can on whole inclined plane, be configured to uniform density, also can be to be configured along with leaving light entrance face mode from dense to sparse.In addition, also can replace by printing and form this diffuse reflector, but will with the corresponding part of the allocation position of diffuse reflector, make frosting and roughening.

In addition, in the LGP of Figure 14, though dispose diffuse reflector on the inclined plane, the present invention only is confined to this, but also can be disposed on the face arbitrarily outside the light entrance face according to necessity.

In addition, also can dispose in the light entrance face side of planar illuminating device, the transmitance with function that the brightness disproportionation that makes the light that penetrates from light entrance face reduces is adjusted member.

Figure 15 represents to dispose the summary section that transmitance is adjusted the planar illuminating device 180 of member 182.

Planar illuminating device 180 has light source 190, diffusion barrier 14, LGP 18, reflection thin plate 22, transmitance adjustment member 182, prism thin plate 188.

At this, because diffusion barrier, LGP, the reflection thin plate of diffusion barrier 14, LGP 18 and reflection thin plate 22 and planar illuminating device as shown in figure 13 have identical functions, thereby its detailed explanation is omitted.

Light source 190 and has identical constituting by aforesaid led chip 128 and heat sink 130 led array that constitute 124, in the present embodiment, led array 124 respectively with the first light entrance face 18d of each LGP 18 and the second light entrance face 18e mutually in the face of and dispose.That is, between each led array 124 and the first light entrance face 18d and the second light entrance face 18e, do not dispose coupled lens and light mixing.Thus, the feasible light that sends from led array 124 is directly injected LGP 18.

In addition, on the light emergence face 18a of LGP 18, stacked gradually transmitance and adjusted member 182, diffusion barrier 14, prism thin plate 188.At this, prism thin plate 188 has same function with above-mentioned prism thin plate 26, the form of facing mutually with the drift angle and the scattering thin plate 14 of its prism, that is, so that the base of prism disposes with the form that the light entrance face 18a of LGP 18 parallels.

As mentioned above, transmitance is adjusted member 182 and is used for the brightness disproportionation that reduces the light that penetrates from LGP, and a plurality of transmitances that it has transparent membrane 184, be disposed at the surface of transparent membrane 184 are adjusted bodies 186.

Transparent membrane 184 has the shape of film shape, with PET (PET: Port リ エ チ レ Application テ レ Off タ レ one ト), PP (polypropylene), PC (Merlon), PMMA (polymerthyl acrylate), benzyl olefin(e) acid methyl esters and MS resin, シ Network ロ オ レ Off イ Application プ リ マ one) other acrylic resin or COP (cycloolefine polymer: optically transparent member and forming such as.

It is the points of all size with transmitance of regulation that transmitance is adjusted body 186, have shapes such as quadrangle and circle, hexagon, pattern according to the rules, for example according to according to the size of location point, the different pattern (stipple pattern) of configurable number of point, be formed at by printing on the whole surface of LGP 18 sides of transparent membrane 184.

Transmitance is adjusted body 186 so long as diffuse reflector gets final product, for example also can be the material that is coated with hollow beads such as the pigment of the silica that makes light generation scattering, titanium oxide, zinc oxide etc. or resin and glass, zirconia with adhesive, and the surface be because of micro concavo-convex processing and grind the surface roughening pattern that forms.In addition, also can be reflectivity height, the low material of light absorption, for example use the metal of Ag, Al and so on.

In addition, adjust body 186, can use at employed general chalks such as screen painting, hectographic printings as transmitance.As an example, can use that titanium oxide, zinc oxide, zinc sulfate, barium sulfate etc. are scattered in acrylic adhesive and polyester is printing ink in adhesive, the vinyl chloride adhesive etc., or in titanium oxide, be mixed with silica and have the printing ink of scattering.

Transmitance is adjusted member 186, by a plurality of transmitances are adjusted members 186 in accordance with regulations pattern arrangement come to make transmitance adjust the change of pattern density of member 186 in the surface of light guide plate device 18 sides of transparent membrane 184 according to lip-deep position.

At this, (x, pattern density y) are ρ (x to establish the optional position of transmitance member 182, y), if the optional position of the light emergence face (faces of display panels 4 sides) of the backlight unit 180 when never possessing transmitance and adjusting member 182 (x, y) relative brightness of the light of She Chuing be F (x, y).At this moment, (x, y) (x, relation y) satisfies following formula (5) to the pattern density ρ of preferred transmitance adjustment member 182 with relative brightness F.

ρ(x，y)＝c{F(x，y)-F _min}/(F _max-F _min)(5)

In the formula (5), F _MaxBe the high-high brightness of the light that penetrates of the light emergence face of the diffusion barrier 14 of the backlight unit 180 when never possessing transmitance and adjusting member 182, F _MinIt is minimum brightness.And relative brightness F (x is y) then with high-high brightness F _MaxAs datum mark (F _Max=1).

At this, c is a maximal density, preferred 0.5≤c≤1.

In addition, when the density design of the configuration of having carried out transmitance adjustment body according to above-mentioned formula, discern brightness disproportionation with the angle of outside frontal, observing sometimes.For this is improved, preferably on the Density Distribution that calculates, append " uniform Density Distribution (biasing density p b) again.Thus, brightness disproportionation can be reduced, and the angle dependence relation of brightness disproportionation can be eliminated or reduce.

At this, the density p b that preferably will setover is made as 0.01～1.50 (1～150%).And surpass under 1 (100%) the situation in configuration density, transmitance is adjusted body be configured to bilayer.That is, after having disposed transmitance adjustment body on whole, the transmitance of the configuration density of configuration (ρ b-1) is adjusted body.

At this, (x y), is to be present in optional position (x, the per unit area (1mm of transmitance adjustment body 186 y) to so-called pattern density ρ ²) occupation rate, ρ (x, y)=1 o'clock, transmitance is adjusted body 186 and is disposed in the unit are whole, ρ (x, y)=0 o'clock, a bit not configuration in the unit are.

By to satisfy the pattern density ρ (x of above-mentioned formula (5), y) form disposes the transmitance adjustment body 186 that transmitance is adjusted member 182, the reduction of the mean flow rate of the light that penetrates from the light emergence face of backlight unit 180 can be suppressed, and brightness disproportionation can be reduced.Like this, reduce brightness disproportionation by using transmitance to adjust member 182, diffusion barrier 14 does not just need so fully to carry out scattering of light.Consequently, can make diffusion barrier 14 become thinner, in addition, can stop the use of prismatic film, perhaps can reduce the use sheet number of prismatic film, and then lighter and cheap backlight unit can be provided.

Below, be described more specifically in conjunction with specific embodiments and possess the planar illuminating device that has transmitance to adjust member.

In the present embodiment, made backlight unit with the identical formation of backlight unit shown in Figure 15.That is, the backlight unit 180 of present embodiment is made of light source 190, diffusion barrier 14, LGP 18, reflective film 22, transmitance adjustment member 182, prism thin plate 188.

In the present embodiment, being shaped as of LGP 18, the thickness of the first light entrance face 18d and the second light entrance face 18e is made 2mm, with the thickness of the central portion of LGP 10 is that the maximum ga(u)ge of LGP 18 is made 4mm, to make 300mm from the distance of first light entrance face 18d to the second light entrance face, with the length of the direction inwards of LGP 18 promptly the length of the direction parallel and parallel with light emergence face 18a with the first light entrance face 18d of LGP 18 make 500mm.

In addition, it is 1.495 allyl resin that the LGP 18 that is made into, transparent resin have used refractive index, and it is 1.44 silicon particle that scattering particles uses refractive index.The particle diameter of scattering particles is 2000nm.Is 2.06 * 10 with scattering area with this scattering particles in transparent resin ^-12m ², particle density is 220000/mm ³Form mix to disperse and form.

In addition, 0.1mm has been made in the light source 190 (led array 124) and the gap of LGP 18.

In backlight unit 180 as shown in figure 15, adjust the pattern density ρ (x of body 186 in order to calculate the transmitance that satisfies above-mentioned formula (5), y), adjust the member 182 except that not possessing transmitance, measured the backlight unit that uses same structure and shape, the relative brightness F of the light that the light emergence face of the backlight unit when never possessing transmitance adjustment member penetrates (x, y).

At this, with following form measured relative brightness F (x, y).

At first, above-mentioned backlight unit 180 is fixed in XY worktable, in form constant brightness perpendicular to the light emergence face of backlight unit 180.Then, measure the brightness of position of the light emergence face of backlight unit 180 with luminance meter, obtain monochrome information about the ad-hoc location of the light emergence face of LGP 18.

Then,, try to achieve the position on the light emergence face of backlight unit 180 and the relation of brightness by mobile XY worktable, with the high-high brightness of the brightness that calculates as F _Max, with minimum brightness as E _MinWith this high-high brightness F _MaxBe made as 1, with the brightness of each position with respect to the relative ratio of high-high brightness as this position (x, relative brightness F y) (x, y).The measurement result of measuring so as shown in figure 16.At this, the curve map of Figure 16, the longitudinal axis is represented relative brightness, transverse axis is represented the distance of the central part of LGP.

Then, according to the high-high brightness F that measures _MaxWith minimum brightness F _Min, use above-mentioned formula 1 calculate with relative brightness F (x, y) corresponding pattern density ρ (x, y).At this, in the present embodiment, calculated relative brightness F when establishing maximal density c and being c=0.75 (x, y) and pattern density ρ (x, relation y).Relative brightness F (x, y) and pattern density ρ (x, relation y) is proportional, (x y) is minimum brightness F at relative brightness F _MinThe time pattern density ρ (x is 0 y), at high-high brightness F _MaxThe time pattern density ρ (x y) reaches maximal density c=0.75.

Then, based on the relative brightness F that calculates (x, y) and pattern density ρ (x, relation y) calculate relative brightness F (x, y) corresponding pattern density ρ (x, distribution y) with the backlight unit of present embodiment shown in Figure 15.Figure 17 is illustrated in pattern density ρ (x, distribution y) of calculating when making maximal density c for c=0.75.Among Figure 17, the longitudinal axis represents that (x, y), transverse axis is represented the distance of central authorities' (central portion) of LGP to the pattern density p.

Then, based on (x, distribution y) have been made and disposed the transmitance adjustment member 182 that transmitance is adjusted body 186 at the pattern density ρ that calculates, satisfy formula (5) when establishing maximal density c for c=0.75.

At this, in the present embodiment, press the every 0.5mm of width and calculate pattern density p (x, y) distribution, according to the pattern density ρ that calculates (x, y), size by suitable configuration width is the transmitance adjustment body 186 of 0～1mm, has made transmitance and has adjusted member 182.

Here, in the present embodiment, when transmitance being adjusted body and be disposed at whole, promptly (x y) is at 1 o'clock to pattern density ρ, and the transmitance when having disposed by wavelength 550nm is that the transmitance that 33% white ink is made is adjusted body 182.

Adjust member 182 in the transmitance that will make like this and be disposed under the situation of backlight unit 180, measured the relative brightness of the light that penetrates from the light emergence face of backlight unit 180.Measuring method uses that (x, the same method of measuring method y) is measured with having measured above-mentioned relative brightness F.Measurement result as shown in figure 18.At this, in Figure 18, the longitudinal axis is represented relative brightness, and transverse axis is represented the distance of central authorities' (central part) of LGP.In addition, for relatively, remove and do not possess transmitance and adjust the member 182, represent simultaneously from the vertical luminance of the light of the light emergence face ejaculation of the backlight unit of identical formation.

As shown in figure 18, compare, adjust member 182 by the configuration transmitance and can reduce brightness disproportionation with the situation that does not dispose transmitance adjustment member 182.

As mentioned above, at this, preferably maximal density c is made as 0.5≤c≤1.By maximal density is made as more than 0.5, can suppresses the reduction of mean flow rate, and then can penetrate high brightness and uniform light.

In addition, preferred transmitance is adjusted the pattern density ρ of body 186 (x, y)=1, promptly preferably the transmitance when whole configuration transmitance adjusted body 186 is more than 10% below 50%, more preferably is set as more than 20% below 40%.

By transmitance is set as more than 10%, can reduce brightness disproportionation aptly, by being set as below 50%, neither can reduce mean flow rate, also can reduce brightness disproportionation.

In addition, by transmitance being set as more than 20% below 40%, can obtain above-mentioned effect more rightly.

In addition, the shape of transmitance adjustment body also can be a shape arbitrarily such as quadrangle, triangle, hexagon, circle, ellipse.

In addition, when backlight unit has used the LGP of the linear light source of this example and uniaxial extension shape, also transmitance can be adjusted the shape of body and make the elongated belt shape parallel with the axle of linear light source.

At this, in the above-described embodiment, used transparent membrane as the optical component that disposes transmitance adjustment body, but the present invention only is confined to this, also transmitance can be adjusted body and be disposed at diffusion barrier and prism thin plate.For example, also can replace transparent membrane and make transmitance adjust the bodily form to be formed in as shown in figure 15 diffusion barrier 14 or prism thin plate 188.Thus, can reduce components number, reduce manufacturing cost.

In addition, transmitance is adjusted the transmitance adjustment body 186 of member 182 can adjust the pattern density distribution according to the light that incides transmitance adjustment member 182, but both can adjust the size of body 186 and adjust transmitance and adjust the pattern density of body 186 and distribute, also can adjust transmitance and adjust the pattern density of body 186 and distribute by the configuration space that the transmitance that changes definite shape is adjusted body 186 by changing transmitance.

As adjusting the collocation method of body 186 with the corresponding transmitance of pattern density, can use the FM screening to cover variety of ways such as mode, AM core mode, wherein, preferably use the FM screening to cover mode.By using the FM screening to cover mode, transmitance can be adjusted body 186 and make fine and uniform point and disperse to concentrate to dispose, and then can make and be difficult to find out that from the light emergence face of backlight unit transmitance adjusts the configuration pattern of body 186.That is, can prevent to adjust the configuration pattern of body 186 and penetrate uneven light, can penetrate more uniform light thus from the light emergence face projection transmitance of backlight unit.In addition, can prevent that also too small the causing of lattice dimensions is difficult to form transmitance adjustment body 186.

The full-size of preferably transmitance being adjusted body 186 is made as below the 500 μ m, for example when rectangular shape length on one side is made as below the 500 μ m, when elliptical shape major axis is made as below the 500 μ m, more preferably is made as below the 200 μ m.Be made as below the 500 μ m by the full-size of transmitance being adjusted body 186, just be difficult to estimate the shape that transmitance is adjusted body 186, by full-size being made as below the 200 μ m, just be difficult to estimate the shape that transmitance is adjusted body 186, when reality is used as liquid crystal indicator, the shape that transmitance can not adjusted body 186 projects to the light emergence face of backlight unit and causes brightness disproportionation, can reduce brightness disproportionation effectively.

In addition, the further full-size of preferably transmitance being adjusted body 186 is made as below the 100 μ m.By full-size being made as below the 100 μ m, can more effectively size be made below the recognition capability of naked eyes, when reality is used as liquid crystal indicator, the shape that can not make transmitance adjust body 186 projects to the light emergence face of backlight unit and causes brightness disproportionation, can reduce brightness disproportionation more certain and effectively.

In addition, as transmitance being adjusted the method that body is printed in the surface of transparent membrane, can use various printing processes such as screen painting, hectographic printing, intaglio printing, ink jet printing.Hectographic printing has this advantage of highly productive, can make the ink thickness thickening not improve this advantage of transmitance that printing ink concentration also can reduce pattern part even screen painting has.And ink jet printing can be printed on three-dimensional thing, is only as the method that forms transmitance adjustment body on the surface of LGP.

In addition, when transmitance being adjusted body and be printed in transparent membrane surperficial, also alignment mark can be printed in outside the configuring area of stipple pattern of transparent membrane.By making alignment mark be formed at transparent membrane, LGP in the time of can being easy to make and transmitance are adjusted the aligning of member.

In the present embodiment, transmitance is adjusted member be arranged between LGP and the diffusion barrier, but allocation position is not only to be confined to this, but can be disposed between diffusion barrier and the prism thin plate yet.

In addition, be disposed at transparent membrane and transmitance is set adjusts member by transmitance being adjusted body, but the present invention only is confined to this, but the configuration that also surface configuration at diffusion barrier, prism thin plate or LGP can be had transmitance to adjust body is adjusted member as transmitance.Particularly, also can and dispose transmitance with the one side at least of the face (outgoing plane of light) of the opposition side of the LGP of diffusion barrier and adjust body at the face (plane of incidence of light) of the LGP side of diffusion barrier.In addition, also can dispose transmitance and adjust body in the one side at least of the face (outgoing plane of light) of the face (plane of incidence of light) of the light guiding surface side of prism thin plate and the prism thin plate and the opposition side LGP side.In addition, also can directly dispose transmitance at the light emergence face of LGP and adjust body.

Like this, by transmitance being adjusted the surface that body is disposed at diffusion barrier, prism thin plate or LGP, can not use transparent membrane to form transmitance and adjust member, and then can make layer structure simpler.

In addition, by transmitance being adjusted the light emergence face that body directly is disposed at LGP, on above-mentioned effect basis, can be during planar illuminating device in assembling, do not aim at but transmitance is adjusted body and be disposed at position accurately at the brightness disproportionation of the light that penetrates from LGP.

In addition, preferably transmitance being adjusted body, to be disposed at a plurality of places be for example surface and the diffusion barrier rear side of LGP of a plurality of optical components, forms a plurality of transmitances and adjust members.Like this, be disposed at a plurality of optical components, can enlarge the allowance of adjusting the position skew of the configuration pattern of body and the light of injecting in the transmitance of each position, and then can penetrate the uniform light of no brightness disproportionation and irregular colour by transmitance being adjusted body.At this, be disposed at a plurality of local time transmitance being adjusted body, transmitance is adjusted the configuration pattern of body, both can be identical configuration pattern, also can be different configuration patterns.

In addition, in the above-mentioned embodiment, as preferred mode, to satisfy the pattern density ρ (x of above-mentioned formula (5), y) form disposes the transmitance adjustment body that transmitance is adjusted member, but the present invention only is confined to this, but can adjust body according to being used for that the various pattern densities that the generation brightness disproportionation suppresses are disposed transmitance.For example, adjust member, also can make the known transmitance of adjusting body with the form configuration transmitance that has Density Distribution in direction and adjust member perpendicular to the axle of linear light source as transmitance.

In addition, preferably on the surface of transparent membrane, white ink is sneaked into the printing ink (printing ink beyond the white ink) of random color, the colourity of disperseing is adjusted film be disposed on the light emergence face of LGP.At this, the mixing ratio of the printing ink of white ink and random color is, with respect to the printing ink less than 1 of white ink 100 random colors.

Adjust film by configuration colourity, the tone of the light of fine-tuning whole ejaculation, and then can improve color rendition and colorrendering quality.Like this, even when using the low light source of color rendition (color rendering), also can improve color rendition as light source.In addition, the color of the light of fine-tuning whole ejaculation.

Below, be described in detail in conjunction with specific embodiments.

In the present embodiment, use the cold-cathode tube (CCFL) of colour temperature 3500K, the LED element of colour temperature 9150K, these three kinds of light sources of LED element of colour temperature 8500K, measured when disposing colourity and adjusting film and the colourity of the colourity that disposes the various printing ink ratios shown in following table 2 and table 3 emitted light when adjusting film.

Table 2

Table 2

No.	White ink	Purple	Three is monochromatic pinkish red	Pinkish red	Three is monochromatic blue or green
						S0	500	0.0	0.0	0.0	0.0
S1	500	1.5	0.0	0.0	0.0
						S2	500	3.0	0.0	0.0	0.0
S3	500	0.0	1.5	0.0	0.0
						S4	500	0.0	3.0	0.0	0.0
S5	500	0.0	0.0	1.5	0.0
						S6	500	0.0	0.0	3.0	0.0
S7	500	0.0	0.0	0.0	1.5
						S8	500	0.0	0.0	0.0	3.0
S9	260	1.5	0.0	0.0	1.0
						S10	520	1.5	0.0	0.0	1.0
S11	1040	1.5	0.0	0.0	1.0
						S12	1166	1.0	0.0	0.0	2.4
S13	875	1.0	0.0	0.0	2.3
						S14	437	1.0	0.0	0.0	2.3
S15	1750	1.0	0.0	0.0	2.3

Table 3

No.	The white 4707M of high concentration	Blue 4746M	Fuchsin FIL135TC
				A0	500	0.0	0.0
A14	900	1.5	1.5

Measurement result such as Figure 19～shown in Figure 21.

At this, Figure 19 represents to measure respectively the curve map that penetrates, passes the result of the light that various colourities shown in table 2 and table 3 adjust films from the cold-cathode tube (CCFL) of colour temperature 3500K, Figure 20 represents to measure respectively the curve map that penetrates, passes the result of the light that various colourities shown in table 2 and table 3 adjust films from the LED element of colour temperature 9150K, and Figure 21 represents to measure respectively the curve map that penetrates, passes the result of the light that various colourities shown in table 2 and table 3 adjust films from the LED element of colour temperature 8500K.

As Figure 19～shown in Figure 21, adjust the colour temperature that films can be adjusted the light of ejaculation by disposing various colourities.That is, respectively shown in the arrow among Figure 19～Figure 21, the light that can make ejaculation from original light source colour to various looks such as R (redness) direction, Y (yellow) direction, M (fuchsin) directions to skew.

Thus, can improve color rendition and colour temperature reproduction regions.In addition, even under the situation that fluorophor is disposed at blue led ejaculation white light, also can adjust film and improve red colorrendering quality by configuration colourity.

At this, the allocation position that colourity is adjusted film is not particularly limited, both can be disposed between the light emergence face and various optical component of LGP, various optical component each other, also can be disposed between light source and the LGP.

In addition, also can alternative arrangements colourity adjust film, and will be in above-mentioned white ink in accordance with regulations amount sneaked into printing ink behind the various printing ink, be coated on diffusion barrier, prism thin plate, LGP surface etc.

In addition, as shown in Figure 1, in the above-mentioned embodiment, used the face 18a that is formed flatly the light emitting side, formed the LGP of the face of its opposition side, but the LGP that is applied to backlight unit of the present invention is not only to be confined to this shape by the inclined plane.

Below, other configuration example of the LGP that can be applicable to backlight unit of the present invention is described.

Figure 22 A and Figure 22 B represent to can be applicable to other configuration example of the LGP of backlight unit of the present invention.Figure 22 A is the approximate vertical view of expression LGP 28, light mixing 20, light source 12, and Figure 22 B is the summary section of expression LGP 28.And at Figure 22 A and Figure 22 B, because light source 12 and light mixing 20 (20A and 20B) and as shown in Figure 1 light source and light mixing have identical functions, thereby its detailed explanation is omitted.

LGP 28 has the structure that the LGP 18 that makes as shown in Figure 1 reverses up and down, and its light emergence face is made of a pair of first smooth inclined plane 28a and the second inclined plane 28b, and the face of its opposition side is made of tabular surface 28c.The first inclined plane 28a of LGP 28 and the second inclined plane 28b, with thickness from central portion to the end gradually the form of attenuation tilt with respect to tabular surface 28c.With regard to the LGP 28 of this structure, the light from the first light entrance face 28d and the second light entrance face 28e inject penetrates from the first inclined plane 28a and the second inclined plane 28b.

LGP 28 with this shape is also the same with aforesaid LGP 18, constitute with the transparent resin that comprises scattering object, at the scattering section area of establishing the scattering particles that is contained in LGP is Φ, and 1/2nd the length of establishing the LGP of light incident direction is L _G, the density (population of per unit volume) that is contained in the scattering particles of LGP is N _P, correction coefficient is K _CThe time, satisfy Φ N _PL _GK _CValue be more than 1.1 and be below 8.2, and K _CValue is a this relation below 0.1 more than 0.005.Thus, can be that the first inclined plane 28a and the second inclined plane 28b penetrate evenly and the few illumination light of brightness disproportionation from the pair of angled face.

In addition, in the backlight unit 2 of the LGP 18 that has used shape as shown in Figure 1, corresponding with the first inclined plane 18b and the second inclined plane 18c of the opposition side of the light emitting side that is positioned at LGP 18, the shape of reflection thin plate 22 made the formation that tilts to both ends of the surface (the first light entrance face 18d and the second light entrance face 18e) from the central portion of LGP 18, and be applied under the situation of backlight unit at the LGP 28 that will have the shape shown in Figure 22 A and Figure 22 B, be formed flatly reflection thin plate 22 in the mode of the tabular surface 28c that covers LGP 28.

In addition, the LGP 28 shown in Figure 22 A and 22B though be not to form the prism row on the first inclined plane 28a and the second inclined plane 28b, also can form the prism row on these the first inclined plane 28a and the second inclined plane 28b.In addition, can be to form the prism row on the tabular surface 28c also at the face of the opposition side of the light emergence face of LGP 28.

In addition, in that the LGP 28 shown in Figure 22 A and Figure 22 B is applied under the situation of backlight unit,, promptly on the first inclined plane 28b of LGP 28 and the second inclined plane 28c, dispose polarization separating film at the light emitting side of LGP.This polarization separating film can be close to 28c and go up and form, for example polarization separating film is close on the transparent resinous planar plate and is made into the polarization separation plate, also can make the polarization separation plate leave the first inclined plane 28b and the second inclined plane 28c predetermined distance and dispose.

In addition, Figure 23 A and Figure 23 B represent to can be applicable to another other the configuration example of the LGP of backlight unit of the present invention.Figure 23 A is the approximate vertical view of expression LGP 38, light mixing 20, light source 12, and Figure 23 B is the summary section of expression LGP 38.And in Figure 23 A and Figure 23 B, because light source 12 and light mixing 20 (20A and 20B) and as shown in Figure 1 light source and light mixing have identical functions, thereby its detailed explanation is omitted.

In the LGP 38 shown in Figure 23 A and Figure 23 B, the light emergence face of the side that light penetrates, with the face of its opposition side with identical shaped formation.The light emergence face of LGP 38 has the profile of rectangular shape, is made of a pair of first smooth inclined plane 38a and the second inclined plane 38b, and the face of its opposition side is made of a pair of the 3rd smooth inclined plane 38c and the 4th inclined plane 38d too.That is, in the LGP 38, make light emitting side and opposition side thereof, constitute by the pair of angled face that slowly tilts from the mediad both ends.The first inclined plane 38a and second inclined plane 38b angle according to the rules tilt mutually, and be same, and the 3rd inclined plane 38c and the 4th inclined plane 38d also according to the rules angle tilt mutually.The second inclined plane 38b is with respect to the relative angle of the first inclined plane 38a, and is identical with respect to the angle of the 3rd inclined plane 38c with the 4th inclined plane 38d.The both ends thickness of slab of LGP 38 is the thinnest, and to central thickness of slab thickening gradually, central portion is the thickest from both ends.

In the LGP 38 shown in Figure 23, the light that incident from the side comes passes LGP 20 inside, penetrates from the first inclined plane 38a and the second inclined plane 38b.At this moment, though leak a part of light that looses from the 3rd inclined plane 38c and the 4th inclined plane 38d sometimes,, the light that leaking sheds is reflected by the reflection thin plate (not shown) that disposes in the mode at the back side that covers LGP 38, reenters the inside that is mapped to LGP.

Figure 24 is the summary section that the summary of an other example of the expression planar illuminating device (backlight unit) 141 that can be applicable to first embodiment constitutes.In addition, in the present embodiment, for the device of the formation identical with as shown in Figures 1 and 2 backlight unit 10, additional identical symbol omits its detailed explanation, stresses different parts.

Backlight unit 141 has light source 142 and LGP 144.In addition, omitted diagram, but the same with backlight unit 10 as shown in Figures 1 and 2, on the light emergence face of the LGP 144 of backlight unit 141, also dispose diffusion barrier and prism thin plate, dispose reflective film 22 on the inclined plane of LGP 144 (the face side opposite) with light emergence face.

Light source 142 is the same with the led array 124 shown in Figure 12 A and Figure 12 B.

LGP 144 has: the smooth light emergence face 144a of rectangular shaped roughly; Be positioned at light penetrate the opposition side of face 144a, parallel with one side of light emergence face 144a and about the bisecting line X of bisection light emergence face 144a symmetrically, two inclined planes (the first inclined plane 144b and the second inclined plane 144c) of tilting with the angle of regulation with respect to light emergence face; Face, make two light entrance faces (the first light entrance face 144d and the second light entrance face 144e) mutually from the light incident of these led array 124 with two led array 124.The first inclined plane 144b and the second inclined plane 144c are the boundary with bisecting line X, tilt with respect to light emergence face 144a.To central thickness thickening gradually, central portion is the thickest from the first light entrance face 144d and the second light entrance face 144e for LGP 144, and both ends are the thinnest.The part of the first light entrance face 144d side of LGP 144 and the part of the second light entrance face 144e side are by low-refraction member 148 formations of the material different with the other parts (following as mother metal 146) of LGP 144.

Low-refraction member 148 and the mother metal 146 common light entrance face 144c that form except that the face as light entrance face 144c, also are connected with mother metal 146.That is, the face of the light entrance face 144a side of low-refraction member 148, the first inclined plane 144b side, the second inclined plane 144c side and central portion side all is covered in mother metal 146.The cross sectional shape of low-refraction member 148 is for forming the shape of protruding semicircle cone at central portion.

The also available extrinsion pressing of this LGP and the injection-molded method of forming are made.In addition, also can make mother metal 146 and low-refraction member 148 respectively, again low-refraction member 148 be imbedded mother metal 146, perhaps bonding setting.

At this, be Ni if establish the refractive index of low-refraction member 148, the refractive index of establishing mother metal 146 is Nm, then mother metal 146 and low-refraction member 148 satisfy this relation of Nm＞Ni.

Be arranged at a part that comprises light entrance face by the low-refraction member that the refractive index of refractive index ratio mother metal is low, make the light that penetrates from light source incide the low-refraction member, can reduce the Fresnel loss (Off レ ネ Le ロ ス) of penetrating the light that incides light entrance face from light source, improve incident efficient.

In addition, low-refraction member 148 has the function that the light with incident becomes directional light and mixes, and, has the function of coupled lens and mixing portion that is.The backlight unit of present embodiment or not coupled lens and mixing portion and just can make the light that penetrates from light source arrive farther position, and can penetrate illumination light uniform, no brightness disproportionation by the low-refraction member is set.

At this, roughly whole of the light emergence face of preferred LGP forms with the low-refraction member.By the roughly whole face of light emergence face is made the low-refraction member, can make the light that incides LGP from the light source ejaculation incide the low-refraction member, and then can further improve incident efficient.

At this, be that low-refraction member 148 has been made to the protruding half-conical shape of the central portion of LGP 144 among Figure 24, but the present invention only is confined to this.

Figure 25 A～Figure 25 C is the summary section that expression can be applicable to another embodiment of the LGP of backlight unit of the present invention and light source.At this, the cross sectional shape of the LGP shown in Figure 25 A～Figure 25 C all is of similar shape in any position.

Figure 25 A also represents to have the LGP 151 that cross sectional shape is foursquare low-refraction member 152.Figure 25 B represents LGP 153, described LGP 153 has low-refraction member 154, described low-refraction member 154, the cross section is done in echelon, particularly, become exactly, parallel with the face 154b of the opposition side of light entrance face, liken short trapezoidal of face 154a into light entrance face to as the face 154b of central portion one side of LGP 153 as the face 154a of light entrance face.Figure 25 C represents LGP 155, described LGP 155 has low-refraction member 156, and the cross sectional shape of described low-refraction member 156 is a triangle, particularly, face as light entrance face is the bottom surface exactly, the triangle that has fixed point as the central portion side of LGP 155.

Reduction refractive index member is made above-mentioned shape and also can be improved incident efficient.

In addition, the shape of low-refraction member is not only to be confined to above-mentioned example, for example also cross sectional shape can be made different shapes such as semicircle, hyperbola, parabolic shape.

Describe each constitutive requirements of another example of the backlight unit that can be applicable to first embodiment of the present invention above in detail, but the present invention only is confined to this.

Figure 26 is the summary section of other another example that expression can be applicable to the backlight unit of first embodiment of the invention.At this, the device 160 that waits backlight is except being provided with the reflecting member 162 near the light entrance face 144c of LGP 144, constitutes identical with as shown in figure 24 backlight unit 141 basically.Therefore, on both identical inscapes, add identical symbol, and omit its detailed explanation, below, stress the special feature of backlight unit 160.

Reflecting member 162, be near the light emergence face 144a the light entrance face of LGP 144, the light that the first inclined plane 144b and second inclined plane 144c leakage shed reflects and makes it reenter the device that is mapped to LGP, utilizes coating, the part of the light emergence face 144a of evaporation or the bonding first light entrance face 144d side that LGP 144 is set, the part of the light emergence face 144a of the second light entrance face 144e side, these four places of the part of the second inclined plane 144c of the part of the first inclined plane 144b of the first light entrance face 144d side and the second light entrance face 144e side.

As long as reflecting member 162 is to reflect the member that leaks the light that sheds near the light emergence face 144a the light entrance face of LGP 144 and inclined plane 144b, form with regard to available any materials, for example, can by by after filler having been sneaked into PET and PP (polypropylene) etc., make its extend to form the space improved the resin sheet of reflectivity, by having formed minute surface at transparent or white resin sheet surface AM aluminum metallization metal forming such as thin plate, aluminium or serve as the resin sheet of metal forming or the surface has sufficient reflexive sheet metal and forms.

By reflecting member 162 is arranged near the first light entrance face 144d and the second light entrance face 144e near light emergence face 144a, the first inclined plane 144b and the second inclined plane 144c, can prevent near the light entrance face 144c, because of loosing with the leakage of the short light that is easy to penetrate of distance of light source 142, and then can make near the farther position of light entrance face, penetrating of light arrival.Thus, can effectively utilize the light that incides LGP.

In addition, owing to can improve the incident efficient of light, so as present embodiment near the preferred light entrance face that the low-refraction member is arranged at LGP, still, the present invention only is confined to this, even the low-refraction member is not set the utilization ratio that reflecting member also can improve light only is not set.

At this, in the present embodiment, reflecting member is arranged on light emergence face and these two faces of inclined plane, but is disposed under the situation on inclined plane will reflecting thin plate, because the reflection thin plate becomes reflecting member, thereby also can only on a part of light emergence face of light entrance face side, reflecting member be set.

At this, in the first above-mentioned embodiment, all be a slice LGP of explanation, still, the present invention only is confined to this, but also can use the multi-disc LGP to form a light emergence face.

Figure 27 has represented to use an example of a routine planar illuminating device of multi-disc LGP.And in Figure 27, only show for the configuration of clearly representing LGP LGP 18,18 ', 18 " and light sources 12.

A plurality of LGPs are disposed at, and each light emergence face of each LGP becomes same plane and each light entrance face becomes conplane position.Particularly, with LGP 18 and the LGP 18 that is adjacent ' be disposed at, the light emergence face 18a of LGP 18 and adjacent LGP 18 ' light emergence face 18a ' become the first light entrance face 18d of same plane and LGP 18 and adjacent LGP 18 ' the first light emergence face 18d ' become conplane position.And preferred LGP 18 and adjacent LGP 18 ' be close to.In addition, LGP 18 ' " be configured in too, each light emergence face 18a ' and light emergence face 18a " become the same plane and the first light entrance face 18d ' and the first light entrance face 18d ' and become conplane position with LGP 18.In addition, so that each of LGP second light entrance face each other, each first inclined plane each other, each second inclined plane form of all forming same plane each other disposes.

With light source 12 be disposed at LGP 18,18 ', 18 " each first light entrance face, the position that second light entrance face is faced mutually.Thus, with regard to make the light that penetrates from common light source 12 incide LGP 18,18 ', 18 " each first light entrance face, second light entrance face on.

Form a light emergence face by a plurality of LGPs of such configuration arranged side by side, can make more large-area planar illuminating device.Like this, can be applicable to the planar illuminating device of more large-area liquid crystal indicator.

In addition, though not shown in Figure 27, diffusion barrier, prism thin plate are all the same with light source, also preferably cover the light emergence face that is formed by a plurality of LGPs with a diffusion barrier, prism thin plate.

In addition, in the above-mentioned embodiment, all be that light emergence face has been made the plane, but the present invention only is confined to this.

Figure 28 A～Figure 28 C is the figure of another embodiment of expression planar illuminating device, Figure 28 A is the approximate three-dimensional map of planar illuminating device 300, Figure 28 B is the side view of planar illuminating device 300, and Figure 28 C is the summary section of section of the length direction of expression planar illuminating device 300.

Planar illuminating device 300 has light source 302, LGP 304, diffusion barrier 306, propylene acid tube 308, reflective film 310.

Shown in Figure 28 C, two light sources 302 dispose in the mode that clips LGP 304 therebetween.Light source 302 has a plurality of LED302a, and shown in Figure 28 B, LED302a is configured to ring-type along the light entrance face of LGP 304.At this, can use above-mentioned various LED as LED302a.

Shown in Figure 28 B, LGP 304 has light emergence face is formed circle, periphery made the hollow drum of light emergence face on the section perpendicular to the incident direction of the light that penetrates from light source 302.In addition, shown in Figure 28 C, LGP 304 from be equivalent to cylinder above and below light entrance face (the axial end of drum) to central thickness thickening gradually, the thickness maximum of central portion, the thickness minimum at both ends.That is, the cross sectional shape of the LGP 304 of the direction that parallels with the incident direction of the light that penetrates from light source 302 for and above-mentioned identical shapes such as LGP 18, be incident direction at light, become thick more shape from light entrance face thickness far away more.

Diffusion barrier 306 is disposed on the light emergence face of LGP 304.That is, the form with the outer peripheral face of the LGP 304 that covers drum is configured to cylindric.

Propylene acid tube 308 is hollow drum, is disposed at the periphery of diffusion barrier 306.In addition, propylene acid tube 308 usefulness transparent resins form.

Reflective film 310 is disposed at the inclined plane side of LGP 304, promptly is disposed at the inner face side of the LGP 304 of drum.

That is, planar illuminating device 300 is by the reflective film 310 of stacked drum, LGP 304, diffusion barrier 306, propylene acid tube 308 form in order from the inboard.

At this, planar illuminating device 300 is except outer shape is drum, and the various formations all planar illuminating device with above-mentioned are the same, thereby, the detailed description of omitting shape, material etc.

Planar illuminating device 300 is to make the light that incides LGP 304 from light source 302 carry out scattering with inner scattering particles equally, directly or at reflective film 310 reflects, and penetrates from light emergence face, passes diffusion barrier 306, propylene acid tube 308 backs are penetrated.

In the planar illuminating device 300, the outer peripheral face of cylinder has light emergence face, can penetrate light from whole of outer peripheral face.Like this, can use as fluorescent lamp at the comprehensive ejaculation light of 360 degree.

Like this, planar illuminating device of the present invention also can be made the same with the bar-shaped fluorescent lamp that uses as lighting device bar-shaped, also can be applicable to the purposes the same with fluorescent lamp.

In addition, in the present embodiment, just diffusion barrier is disposed at the light emergence face of LGP, but, also can reaches and above-mentioned the same effect by the configuration various optical components the same with above-mentioned planar illuminating device.

In addition, the shape of planar illuminating device is not only to be confined to drum.

Figure 29 is the figure of another other embodiment of expression planar illuminating device, and Figure 29 A is the summary side elevation of planar illuminating device 320, and Figure 29 B is the summary section of expression along the section of planar illuminating device 320 length directions.

Shown in Figure 29 A and Figure 29 B, planar illuminating device 320 has light source 322, LGP 324, reflective film 326.In addition, not shown among the figure, but the same with planar illuminating device 300, dispose diffusion barrier and propylene acid tube at the outer peripheral face of LGP 324.

Planar illuminating device 320, the section perpendicular with the incident direction of the light that penetrates from light source 322 forms, with the semicircular cylinder shape behind planar illuminating device 300 half points of circle.That is, light source 322, LGP 324 and reflective film 326 are formed the semicircular cylinder shape.

Preferably also can use the planar illuminating device of semicircular cylinder shape like this.For example the same when being disposed at the roof,, illumination is penetrated make indoorly to become bright less than the roof side by making the semicircular cylinder shape as room lighting with fluorescent lamp.Thus, can be effectively with room lighting.

In planar illuminating device shown in Figure 28 300, the LGP of drum is made the bar-shaped of straight tube, but also the LGP of drum can have been made the bending curved tube, planar illuminating device is done circlewise.

Figure 30, Figure 31 and Figure 32 represent planar illuminating device has been made the outline elevation of an embodiment of the shape of ring-type respectively.

Planar illuminating device 330 as shown in figure 30 has 332,4 LGPs 334 of 8 light sources.

LGP 332 is drums of making light emergence face with outer peripheral face, is thickness from end face to the central portion shape of thickening gradually.In addition, LGP 334 is swan-necks that the Central Line of the cylinder from the end face to the end face becomes the circular arcs of 90 degree.

The mode that this LGP 332 is faced mutually with the end face and the end face of adjacent LGP 332 disposes, and connected 4 LGPs 332 become a tubular shape.

In addition, the end face of LGP 334 disposes light source 332 respectively.

By so LGP 334 is made the bend pipe shape and connected configuration a plurality ofly, can become the planar illuminating device of ring-type.

In addition, in planar illuminating device 330, utilize 4 LGPs to make the planar illuminating device of ring-type, but be not only to be confined to this, for example shown in Figure 31, be circular shape by the Central Line that makes a LGP become drum, use the planar illuminating device 340 that has a LGP 344 and be disposed at two light sources 342 of its end face, do planar illuminating device circlewise.

In addition, the arc angle of the Central Line of the drum by setting LGP, the LGP of available any number is done circlewise.

In addition, bar-shaped, ring-type that planar illuminating device is not limited to, but can make different shape.

And then shown in Figure 32 A, LGP is being made under the situation of drum, preferably form groove 354a in the part of the LGP 354 of the drum of planar illuminating device 350.That is, shown in Figure 32 B, with the perpendicular section of the incident direction of the light that penetrates from light source 342 on, preferably form groove 354a in the part of LGP 354.

By on LGP 354, forming groove 354a, can dispose reflective film 346 simply in the inner face side of LGP 354.

Below, second embodiment of planar illuminating device of the present invention is described.

In second embodiment, use the light conducting member shown in Figure 33 A and Figure 33 B to constitute planar illuminating device.Figure 33 A represents the light conducting member of second embodiment and the schematic plan of the part of the light source that uses in order to make light incide this light conducting member, and Figure 33 B is the schematic cross sectional view of the B-B line of the light conducting member shown in Figure 33 A.

Shown in Figure 33 B, light conducting member 90 is made of a plurality of plastic optical fibers (POF) 92 and the transparent shell 94 of accommodating these plastic optical fibers.Plastic optical fiber (below abbreviate " optical fiber " as) 92 and housing 94 all are to use to have flexual material and forms.Shown in Figure 33 B, with each plastic optical fiber (below abbreviate " optical fiber " as) 92 so that the form that the gap between each optical fiber becomes minimum closely be disposed in the housing 94.That is, dispose with the form that is connected with six optical fiber around the optical fiber.The basic rectangular flat shape uniformly of light conducting member 90 usefulness thickness constitutes.

At this, a plurality of optical fiber 92 that are contained in the housing 94 can be by forming with bonding each mutual sides such as bonding agents.In addition, by having flexual transparent resin material filling in the gap of a plurality of optical fiber of laminated configuration, also can bonding each optical fiber.In order to make light enter into the inside (Austria) side, preferably be mingled with air layer in the gap of optical fiber against each other, by being mingled with this air layer, can when using, further suppress the generation of brightness disproportionation as light conducting member.

Like this, the light conducting member 90 of present embodiment forms a kind of lit-par-lit structure by a plurality of optical fiber 92 are configured to layered laminate, if consider the formed space, border between each optical fiber, then preferably constitutes light conducting member 90 with 3～5 folded layer by layer structures.For example, be 1.0mm at fibre diameter, when constituting light conducting members with 3 layers of structure, the thickness of light conducting member is the thickness of not enough 3.0mm.In addition, be under the situation of 0.5mm constructing and make fibre diameter with identical 3 layers, the thickness of light conducting member is the thickness of not enough 1.5mm.

Constituting of optical fiber 92, the core that constitutes by the organic compound that with the polymer is matrix, the cladding part that constitutes by the refractive index organic compound different with this core part.At core and cladding part,, and can add additive such as stabilizing agent for example for improving cladding part and the ageing resistance of core and the purpose of durability.

Preferred cladding part is made of polymer and has the refractive index lower than the refractive index of core, in addition, preferably has permeability with respect to the light that is sent by point source of light.

Core is made of polymer, uses to have the material of permeability with respect to the light that is sent by point source of light, and contains the scattering particles that makes light generation scattering.

1/2nd the length that at the scattering section area of establishing the scattering particles that is contained in optical fiber 92 is the optical fiber of Φ, light incident direction is L _G, the density (population of per unit volume) that is contained in the scattering particles of optical fiber is N _P, correction coefficient is K _CThe time, satisfy Φ N _PL _GK _CValue be more than 1.1 and be below 8.2, and 0.005≤K _C≤ 0.1 this relation.Because optical fiber comprises the scattering particles that satisfies this relation, thereby can penetrate even and the few illumination light of brightness disproportionation from the side.

In addition, also can in the resin material that constitutes optical fiber, add above-mentioned plasticizer.Thus, can improve the flexibility of optical fiber, realize flexible light conducting member.

Light source 82 shown in Figure 33 A, possess the led array 84 that disposes a plurality of LED86 arranged, with the corresponding coupled lens 88 of each LED86.Shown in Figure 33 A, dispose the R-LED86R that sends red light in the both ends of the surface of each optical fiber 92, send the G-LED86G of green light and send wherein a kind of LED86 of the B-LED86B of blue light.The form that becomes the LED of different colors with each LED (R-LED86R, G-LED86G and B-LED86B) that is disposed at led array and adjacent LED disposes.If make of the side incident of the light of versicolor LED (R-LED86R, G-LED86G and B-LED86B) from optical fiber 92, then utilize the scattering object of the inside of optical fiber 92 to make light generation scattering, penetrate versicolor light from the side of each optical fiber 92.Because each optical fiber 92 adjacent each side is against each other, thereby can make the versicolor light that penetrates from the side of these optical fiber carry out colour mixture and become white light.

At this, constitute light source 82 with the led array 84 that disposes versicolor LED with coupled lens 88, versicolor LED is disposed at the end face of each optical fiber 92, but be not only to be confined to this formation, but also can constitute light source with White LED and coupled lens, White LED is disposed at the end face of optical fiber.

In addition, also can only use a certain color in red, blue, green to be used as monochromatic illumination uses.

Figure 32 represents to possess the summary pie graph of the routine backlight unit (planar illuminating device) 100 that this light conducting member 90 is arranged.Shown in figure 32, the backlight unit 100 that possesses the light conducting member 90 that has as shown in figure 33 can be following formation, promptly, dispose reflection thin plate 102 at face (light emergence face) 90a opposition side, on the light emergence face 90a of light conducting member 90, dispose two prism thin plates 104,106, scattering thin plate 108 successively with the light ejaculation that makes light conducting member 90.But backlight apparatus is not the formation that only is confined to shown in figure 32, but also can between the light emergence face 90a of light conducting member 90 and prism thin plate 104 polarization separating film etc. be set.

Constitute reflection thin plate 102, prism thin plate 104,106 and the scatter plate 108 of backlight unit 100 shown in Figure 32, can use the device the same with the backlight unit of above-mentioned first embodiment.In addition, not shown light source among Figure 32, and light source is disposed in front of the paper of light conducting member 90 side and (Austria) side inwards.

Because the light conducting member 90 that stacked like this optical fiber 92 constitutes has pliability, thereby under the situation that the backlight unit 100 that will use this light conducting member uses as the display board relevant with lamp decoration (illumination), can be installed on the wall with curvature, LGP can be applied to the lamp decoration and the POP (POP advertisement) in more kind, more wide use field.

Above, describe planar illuminating device involved in the present invention in detail, but the present invention only is confined to top embodiment, but also can carries out various improvement and change in the scope that does not exceed main idea of the present invention.

The feasibility of using on the industry

Planar illuminating device of the present invention can be used as and is applied to liquid crystal display, crown projecting apparatus, advertisement with planar illuminating devices (backlight unit) such as lamp decoration billboard, indoor, outdoor lightings and uses.

Claims (19)

1. a planar illuminating device is characterized in that,

Possess:

First light source and the secondary light source that separate predetermined distance and dispose;

Be disposed at the LGP between described first light source and the described secondary light source,

Wherein, described LGP has: light emergence face; With described first light source mutually in the face of and comprise first light entrance face on one side of described light emergence face; With described secondary light source mutually in the face of and comprise second light entrance face of the opposite side on described one side,

Get over to central authorities from described first light entrance face and described second light entrance face, thickness is thick more,

Comprise scattering particles, described scattering particles makes from first and second light entrance face incident of described LGP and in the light generation scattering of internal communication, and satisfies following formula (1):

1.1≤Φ·N _P·L _G·K _C≤8.2(1)

Wherein, the scattering section of scattering particles is long-pending to be Φ, and 1/2nd length of the light incident direction of described LGP is L _G, the density of scattering particles is N _P, correction coefficient is K _C, make K _CBe more than 0.005 below 0.1.

2. planar illuminating device as claimed in claim 1 is characterized in that,

The profile of the described light emergence face of described LGP is a rectangle.

3. planar illuminating device as claimed in claim 2 is characterized in that,

Be formed flatly the described light emergence face of described LGP, described LGP, opposition side at described light emergence face, have first inclined plane and second inclined plane, described first inclined plane and the bisecting line of second inclined plane with respect to the described light emergence face parallel with described one side of described light emergence face tilt symmetrically and form.

4. planar illuminating device as claimed in claim 3 is characterized in that,

Make the polarized component of regulation see through and make the polarization separating film of polarized component reflection in addition selectively, on the described light emergence face of described LGP, form as one with described LGP.

5. planar illuminating device as claimed in claim 2 is characterized in that,

The described light emergence face of described LGP, first inclined plane and second inclined plane that are tilted symmetrically by the bisecting line with respect to the described light emergence face parallel with described one side of described light emergence face form, further, the face of the opposition side of described light emergence face also is to be formed by the 3rd inclined plane and the 4th inclined plane that the bisecting line with respect to the described light emergence face parallel with described one side of described light emergence face tilts symmetrically.

6. planar illuminating device as claimed in claim 2 is characterized in that,

The described light emergence face of described LGP is formed by first inclined plane and second inclined plane that the bisecting line with respect to the described light emergence face parallel with described one side of described light emergence face tilts symmetrically, and is formed flatly the face of the opposition side of described light emergence face.

7. as each described planar illuminating device in the claim 1～6, it is characterized in that,

Described first light source and secondary light source all use led array and a plurality of lens and constitute, described led array is that a plurality of RGB-LED that possess red light emitting diodes, green LED and blue LED are listed alignment arrangements one, and described a plurality of lens are corresponding with the light emitting side of described red light emitting diodes, described green LED and described blue LED respectively and dispose.

8. planar illuminating device as claimed in claim 7 is characterized in that,

Each of described a plurality of lens all is the globe lens of spherical transparent.

9. as each described planar illuminating device in the claim 1～6, it is characterized in that,

Described first light source and described secondary light source all are led array, the support portion that described led array has a plurality of led chips and the described led chip that forms a line is supported,

If the length of the direction vertical with the described light-emitting face of described LGP of described led chip is a, the length of establishing described led chip orientation is b, when the configuration space of establishing described led chip is p, then satisfies the relation of p＞b＞a.

10. planar illuminating device as claimed in claim 7 is characterized in that,

Described first light source and described secondary light source all have two the above led array,

And have following formation, and promptly adopt at least a method in mechanical connection method and the chemical connection process, make between the led chip that comprises in the led chip of described led array and other the described led array and to leave with predetermined distance and stacked.

11. planar illuminating device as claimed in claim 1 is characterized in that,

Have a plurality of described LGPs,

Described a plurality of LGP is configured in, and each light emergence face of each LGP becomes same plane and each light entrance face becomes conplane position.

12. planar illuminating device as claimed in claim 1 is characterized in that,

Described LGP disposes a plurality of scattered reflection bodies at least one face of the face except that described first light entrance face and described second light entrance face.

13. planar illuminating device as claimed in claim 12 is characterized in that,

Described scattered reflection body is along with away from described first light entrance face and described second light entrance face and dispose closely more.

14. planar illuminating device as claimed in claim 3 is characterized in that,

Described LGP, the face except described first light entrance face and described second light entrance face at least the one side on dispose a plurality of scattered reflection bodies,

Described scattered reflection body is disposed at described first inclined plane and described second inclined plane.

15. planar illuminating device as claimed in claim 1 is characterized in that,

The part of the described first light entrance face side of described LGP and the part of the described second light entrance face side are formed by the material different with other parts, when the refractive index that the refractive index at the material of the part of a part of establishing the described first light entrance face side and the described second light entrance face side is Ni, establish the material of other parts is Nm, satisfy the relation of Nm＞Ni.

16. planar illuminating device as claimed in claim 3 is characterized in that,

Also have reflecting element, described reflecting element is configured in respectively on described first light entrance face described light emergence face, described first inclined plane near described first light entrance face, the described light emergence face near described second light entrance face and described second light entrance face described second inclined plane nearby nearby of described LGP.

17. a planar illuminating device possesses:

First light source and the secondary light source that separate predetermined distance and dispose;

Be disposed between described first light source and the described secondary light source, and use the light conducting member that is close to many plastic optical fibers of laminated configuration each other and constitutes,

Described first light source is faced mutually and is disposed with an end face of described plastic optical fiber, and described secondary light source is faced mutually and disposed with another end face,

Described plastic optical fiber comprises and makes from two surface feeding sputterings and in the light generation scattering of internal communication and satisfy the scattering particles of following formula (1),

1.1≤Φ·N _P·L _G·K _C≤8.2(1)

Wherein, the scattering section of scattering particles is long-pending to be Φ, and 1/2nd length of described plastic optical fiber is L _G, the density of scattering particles is N _P, correction coefficient is K _C, K _CBe more than 0.005 below 0.1.

18. planar illuminating device as claimed in claim 17 is characterized in that,

Described light conducting member also has transparent housing, disposes described many plastic optical fibers in described housing inner stacks.

19. as claim 17 or 18 described planar illuminating devices, it is characterized in that,

Described first light source and secondary light source all use led array and a plurality of lens and constitute, in the described led array with red light emitting diodes, green LED and blue LED with configuration side by side with every corresponding mode of described many plastic optical fibers, described a plurality of lens are corresponding with the light emitting side of described red light emitting diodes, described green LED and described blue LED respectively and dispose.

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