CN112526783A

CN112526783A - Display device

Info

Publication number: CN112526783A
Application number: CN202011607047.6A
Authority: CN
Inventors: 陈明伦; 林义文; 陈政传; 林晋安; 田堃正
Original assignee: AU Optronics Corp
Current assignee: AU Optronics Corp
Priority date: 2020-08-14
Filing date: 2020-12-30
Publication date: 2021-03-19
Anticipated expiration: 2040-12-30
Also published as: CN112526783B; TWI738465B; TW202206908A

Abstract

A display device comprises a liquid crystal module and a backlight module. The liquid crystal module comprises a double-domain liquid crystal layer, a lower polaroid and an upper polaroid. The lower polarizer has a penetrating axis along a first direction. The backlight module comprises a light-emitting module, a first prism sheet, a second prism sheet, a reflective polarization membrane and a light-spreading membrane. The reflective polarizing film has a transmission axis along a third direction, wherein an included angle between the third direction and the first direction is within a range of 0 +/-5 degrees. The light diffusion film is provided with a plurality of first microstructures extending along a first extending direction. The light emitted by the light-emitting module is emitted through the light-emitting surface of the optical plate and then sequentially passes through the first prism sheet, the second prism sheet, the reflective polarization membrane, the light-spreading film and the liquid crystal module to form image light.

Description

Display device

Technical Field

The present invention relates to an optical module, and more particularly, to a display device.

Background

Due to the development of electronic products such as televisions, computers, notebook computers, mobile devices, smart phones, and the like, the improvement of the use experience of the display device has become a trend in the market. The conventional display device uses a multi-domain Vertical Alignment (VA) liquid crystal layer to improve the color washout problem of a display screen displayed by the display device at a large viewing angle. In addition, In order to improve the problem of poor Gamma (Gamma) value of the display screen at a large viewing angle, the display device may use an In-Plane-Switching (IPS) liquid crystal layer, or the display device may dispose a micro-structure film on the IPS liquid crystal layer.

However, the cost of providing the microstructure film is high, so that the overall cost of the display device is increased, and the contrast of the display screen of the display device is poor. Furthermore, although the higher the number of domains (domains) of the liquid crystal layer is, the color shift problem of the display screen can be reduced, the lower the light energy utilization rate of the display device is, and the brightness of the display screen is not good. On the contrary, in a display device having a small number of liquid crystal layer regions, such as a dual-domain liquid crystal layer, the light shape of the surface light source provided by the backlight module of the display device is not symmetrical due to the matching manner of the film layers, and the light leakage at a large viewing angle, i.e., a vertical viewing angle and a horizontal viewing angle, is also caused at the lowest gray scale level.

Disclosure of Invention

The invention provides a display device, which can effectively reduce the problem of asymmetric light shape of a surface light source and the problem of light leakage of a large viewing angle when a display picture presented by the display device is at the lowest gray scale.

The display device of an embodiment of the invention includes a liquid crystal module and a backlight module. The liquid crystal module comprises a double-domain liquid crystal layer, a lower polaroid and an upper polaroid. The liquid crystal molecules of the two-domain liquid crystal layer are aligned in a horizontal alignment direction when no voltage is applied. The lower polarizer has a penetrating axis along a first direction, wherein an included angle between the first direction and the horizontal arrangement direction falls within a range of 45 +/-5 degrees. The upper polarizer has a penetrating axis along a second direction. The lower polarizer, the two-domain liquid crystal layer and the upper polarizer are arranged in sequence in an arrangement direction. The backlight module is used for providing a surface light source. The backlight module comprises a light-emitting module, a first prism sheet, a second prism sheet, a reflective polarization membrane and a light-spreading membrane. The light emitting module comprises an optical plate and a light source. The optical plate is provided with a light emergent surface and a light incident surface. The light source is arranged on one side of the light incident surface of the optical plate. The reflective polarizing film has a transmission axis along a third direction, wherein an included angle between the third direction and the first direction is within a range of 0 +/-5 degrees. The light diffusion film is provided with a plurality of first microstructures extending along a first extending direction. The light emitting module, the first prism sheet, the second prism sheet, the reflective polarization membrane, the light spreading membrane and the liquid crystal module are sequentially arranged in the arrangement direction. The light emitted by the light-emitting module is emitted through the light-emitting surface of the optical plate and then sequentially passes through the first prism sheet, the second prism sheet, the reflective polarization membrane, the light-spreading film and the liquid crystal module to form image light.

In view of the above, in the display device according to an embodiment of the invention, the light spreading film is disposed on the reflective polarization film, and the films in the display device are collocated, so that the light shape of the surface light source provided by the backlight module of the display device is better, and the display effect of the display device is better.

Drawings

Fig. 1 is a perspective exploded view of a display device according to an embodiment of the present invention.

Fig. 2 is a cross-sectional view of a light-diffusing film of a display device according to an embodiment of the present invention.

Fig. 3 is a graph of luminance gain ratio of the display device according to an embodiment of the invention with respect to the average height L/average pitch P between the first microstructures.

FIG. 4 is a cross-sectional view of an upper polarizer of a display device according to an embodiment of the present invention.

FIG. 5A is a graph of gamma versus gray scale for a display device according to an embodiment of the invention, wherein the second microstructures are not disposed on the upper polarizer in the vertical viewing direction.

FIG. 5B is a graph of gamma versus gray scale for a second microstructure disposed on the upper polarizer in a vertical viewing angle direction in a display device according to an embodiment of the invention.

Fig. 6A is a cross-sectional view of a first prism sheet or a second prism sheet of a display device according to an embodiment of the invention.

Fig. 6B is a partially enlarged view of the first prism microstructure or the second prism microstructure of fig. 6A.

Fig. 7 is a graph of relative luminance values in a horizontal viewing angle direction versus viewing angle when a radius of curvature of a prism tip of a first prism microstructure of a first prism sheet is larger and smaller than a radius of curvature of a prism tip of a second prism microstructure of a second prism sheet at a lowest gray scale in a display device according to an embodiment of the invention.

FIG. 8 is a graph of relative luminance values with respect to viewing angle in a horizontal viewing angle direction when the prism refractive index of the first prism sheet is greater than and less than the prism refractive index of the second prism sheet at the lowest gray level in the display device according to an embodiment of the invention.

Fig. 9 is a graph of relative luminance values in a horizontal viewing angle direction versus viewing angle when the haze of the first atomized structure layer of the first prism sheet is greater than or less than the haze of the second atomized structure layer of the second prism sheet at the lowest gray scale in the display device according to an embodiment of the invention.

Fig. 10A is an example of an outgoing light shape of a display device according to an embodiment of the invention.

Fig. 10B is an example of the light-emitting shape of the backlight module of the display device according to the embodiment of the invention.

FIG. 11A is a graph of relative luminance values with respect to viewing angle in the horizontal viewing angle direction at the lowest gray level of a display device according to an embodiment of the present invention.

FIG. 11B is a graph of relative luminance values with respect to viewing angle in the vertical viewing angle direction at the lowest gray level of a display device according to an embodiment of the present invention.

Description of reference numerals:

10: display device

100: liquid crystal module

110: dual domain liquid crystal layer

120: lower polarizer

130: upper polarizer

132: second microstructure

132F: second transition region

132S, 252S, 222S, 232S: surface of

134. 224, 234, 254: substrate

134S, 224S1, 234S1, 254S: upper surface of

200: backlight module

210: light emitting module

212: optical plate

212S 1: light emitting surface

212S 2: light incident surface

214: light source

220: first prism sheet

222: first prism microstructure

222F: third turning region

222T, 232T: tip end

224S2, 234S 2: lower surface

226: first atomizing structural layer

230: second prism sheet

232: second prism microstructure

232F: third turning region

236: second atomization structural layer

240: reflection type polarization diaphragm

250: light diffusion film

252: first microstructure

252F, 252F 1: first turning region

260: quantum dot layer

A: direction of arrangement

C1, C2, C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16: curve line

D1: a first direction

D2: second direction

D3: third direction

E1: first direction of extension

E2: second direction of extension

E3: a third direction of extension

E4: a fourth direction of extension

H: horizontal arrangement direction

L': height difference

LM1, LM2, LM3, LM4, LM 5: local extremum

P: distance between each other

R1, R2: radius of curvature

Detailed Description

Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts.

It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" or "directly connected to" another element, there are no intervening elements present. As used herein, "connected" may refer to physical and/or electrical connections. Further, "electrically connected" or "coupled" may mean that there are additional elements between the elements.

As used herein, "about", "approximately", or "substantially" includes the stated value and the average value within an acceptable range of deviation of the specified value as determined by one of ordinary skill in the art, taking into account the measurement in question and the specified amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" may mean within one or more standard deviations of the stated value, or within ± 30%, ± 20%, ± 10%, ± 5%. Further, as used herein, "about", "approximately" or "substantially" may be selected based on optical properties, etch properties, or other properties, with a more acceptable range of deviation or standard deviation, and not all properties may be applied with one standard deviation.

Unless defined otherwise, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present invention and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Fig. 1 is a perspective exploded view of a display device according to an embodiment of the present invention. Referring to fig. 1, a display device 10 according to an embodiment of the invention includes a liquid crystal module 100 and a backlight module 200. The liquid crystal module 100 includes a two-domain (two domains) liquid crystal layer 110, a lower polarizer 120, and an upper polarizer 130. The lower polarizer 120, the two-domain liquid crystal layer 110 and the upper polarizer 130 are sequentially arranged in an arrangement direction A. The backlight module 200 includes a light-emitting module 210, a first prism sheet 220, a second prism sheet 230, a reflective polarization film 240, and a light-spreading film 250. The light-exiting module 210, the first prism sheet 220, the second prism sheet 230, the reflective polarizing film 240, the light-diffusing film 250 and the liquid crystal module 100 are sequentially arranged in the arrangement direction a.

In detail, the liquid crystal molecules of the dual domain liquid crystal layer 110 of the present embodiment are aligned along a horizontal alignment direction H when no voltage is applied. The lower polarizer 120 has a penetrating axis along a first direction D1, wherein an angle between the first direction D1 and the horizontal arrangement direction H is within a range of 45 ± 5 degrees. The upper polarizer 130 has a penetrating axis along a second direction D2, wherein an included angle between the second direction D2 of the upper polarizer 130 and the first direction D1 of the lower polarizer 120 is within a range of 90 + -5 degrees. In one embodiment, the second direction D2 and the first direction D1 are preferably perpendicular to each other.

In the present embodiment, the backlight module 200 is used to provide a surface light source. Specifically, the backlight module 200 obtains the optical module 210 including an optical plate 212 and a light source 214. The optical plate 212 has a light emitting surface 212S1 and a light incident surface 212S 2. The light source 214 is disposed at one side of the incident surface 212S2 of the optical plate 212. The Light source 214 is, for example, a Light-emitting diode (LED) Light source, a sub-millimeter Light-emitting diode (mini LED) Light source, or other suitable Light sources. The light emitted from the light exit module 210 passes through the light exit surface 212S1 of the optical plate 212, and then passes through the first prism sheet 220, the second prism sheet 230, the reflective polarization film 240, the light spreading film 250 and the liquid crystal module 100 in sequence to form an image light. Fig. 1 illustrates that the light exit surface 212S1 of the optical plate 212 is adjacent to the light entrance surface 212S 2. That is, the optical plate 212 of fig. 1 can be a light guide plate, but the invention is not limited thereto. In one embodiment, the optical plate can be a diffusion plate, and the light emitting surface is opposite to the light incident surface. That is, the light source is disposed below the optical plate. In the display device 10 according to an embodiment of the present invention, when the optical plate 212 is a light guide plate, the overall volume of the display device 10 is small; when the optical plate is a diffusion plate, the light source is arranged below the optical plate, and the light-emitting light shape of the backlight module can be adjusted through the position of the light source, so that the light-emitting light shape of the backlight module is uniform.

In one embodiment, the backlight module 200 further includes a quantum dot (quantum dots) layer 260 disposed on the optical plate 212, and the light source 214 includes a blue light source. The quantum dot layer 260 is disposed between the optical plate 212 and the first prism sheet 220. In another embodiment, the quantum dot layer 260 can be directly disposed on the light exit surface 212S1 of the optical plate 212. In the display device 10 according to the embodiment of the invention, the backlight module 200 includes the quantum dot layer 260, so that the color rendering of the surface light source provided by the backlight module 200 is better.

In the present embodiment, the reflective polarizing film 240 has a penetrating axis along a third direction D3, wherein an included angle between the third direction D3 and the first direction D1 is within a range of 0 ± 5 degrees. In one embodiment, the third direction D3 and the first direction D1 are preferably parallel to each other.

Fig. 2 is a cross-sectional view of a light-diffusing film of a display device according to an embodiment of the present invention. Referring to fig. 1 and fig. 2, in the present embodiment, the light diffusing film 250 has a plurality of first microstructures 252 extending along a first extending direction E1. Specifically, the light diffusing film 250 includes a substrate 254, and the first microstructures 252 are disposed on the substrate 254 on an upper surface 254S opposite to the optical plate 212, but the invention is not limited thereto. Furthermore, the first microstructure 252 has a plurality of first turning regions 252F. The first inflection region 252F is a region where a height difference L' along the arrangement direction a between the first microstructure 252 at each local extreme value with respect to the surface 252S of the optical plate 212 and its adjacent local extreme value falls within a range of 0 to 10%, where the height is a distance between the surface 252S of the first microstructure 252 and the upper surface 254S of the substrate 254. The extending direction of the first turning region 252F is perpendicular to the arrangement direction of the first microstructures 252. Incidentally, in the first transition region 252F1 of fig. 2, the first transition region 252F1 includes local extrema LM2, LM3, and LM 4. The first turning region of local extremum LM2 is a region in which the height difference between local extremum LM1 and LM3 adjacent thereto falls within the range of 0 to 10%. Similarly, the first turning region of the local extremum LM3 is a region where the height difference between the local extremum LM2 and the local extremum LM4 adjacent thereto falls within the range of 0 to 10%, and the first turning region of the local extremum LM4 is a region where the height difference between the local extremum LM3 and the local extremum LM5 adjacent thereto falls within the range of 0 to 10%. Therefore, for convenience of illustration, the first inflection region 252F1 of fig. 2 includes the three first inflection regions of the local extrema LM2, LM3 and LM 4.

In the embodiment, the ratio of the projected area of the first turning region 252F on the light diffusing film 250 relative to the upper surface 254S of the optical plate 212 to the projected area of the first microstructure 252 on the upper surface 254S of the light diffusing film 250 is greater than or equal to 30% and less than or equal to 60%.

Fig. 3 is a graph of luminance gain ratio of the display device according to an embodiment of the invention with respect to the average height L/average pitch P between the first microstructures. Referring to fig. 2 and fig. 3, in the present embodiment, the first microstructures 252 of the light diffusing film 250 further satisfy the following condition: L/P is less than or equal to 4% and less than or equal to 25%, where L is the average height difference of the first microstructures 252 and P is the average pitch of the first microstructures 252. Fig. 3 illustrates that different L/P yields different luminance gain ratios. In a preferred embodiment, L/P is 4%.

FIG. 4 is a cross-sectional view of an upper polarizer of a display device according to an embodiment of the present invention. Referring to fig. 1 and fig. 4, in the present embodiment, the upper polarizer 130 has a plurality of second microstructures 132 along a second extending direction E2, wherein an included angle between the second extending direction E2 and the horizontal arrangement direction H is less than or equal to 20 degrees. Specifically, the upper polarizer 130 includes a substrate 134, and the second microstructure 132 is disposed on the upper surface 134S of the substrate 134 opposite to the optical plate 212, but the invention is not limited thereto. Furthermore, the second microstructure 132 has a plurality of second turning regions 132F. The second turning region 132F is a region where a height difference L' in the arrangement direction a between the second microstructure 132 at each local extreme value with respect to the surface 132S of the optical plate 212 and its adjacent local extreme value falls within a range of 0 to 10%, where the height is a distance between the surface 132S of the second microstructure 132 and the upper surface 134S of the substrate 134. The extending direction of the second turning region 132F is perpendicular to the arrangement direction of the second microstructures 132.

In the embodiment, the ratio of the projection area of the second turning region 132F on the upper polarizer 130 relative to the upper surface 134S of the optical plate 212 to the projection area of the second microstructure 132 on the upper surface 134S of the upper polarizer 130 is greater than or equal to 85% and less than or equal to 93%.

FIG. 5A is a graph of gamma versus gray scale for a display device according to an embodiment of the invention, wherein the second microstructures are not disposed on the upper polarizer in the vertical viewing direction. FIG. 5B is a graph of gamma versus gray scale for a second microstructure disposed on the upper polarizer in a vertical viewing angle direction in a display device according to an embodiment of the invention. Referring to fig. 5A and 5B, in fig. 5A, curves C1, C3, and C5 are graphs of gamma values at viewing angles of 30, 45, and 60 degrees with respect to gray scale in the vertical viewing angle direction, respectively; in fig. 5B, curves C2, C4, C6 are graphs of gamma values at viewing angles of 30, 45, 60 degrees with respect to gray scale in the vertical viewing angle direction, respectively. Wherein the average gamma value of the curve C1 is about 1.2, and the average gamma value of the curve C2 is about 1.3; the average gamma value of curve C3 is about 0.5, and the average gamma value of curve C4 is about 0.8; the average gamma value of curve C5 is about-0.1 and the average gamma value of curve C6 is about 0.5. That is, when the second microstructure 132 is disposed on the upper polarizer 130 in the display device 10 according to the embodiment of the invention, the gamma value of the display device 10 is better, and the second microstructure 132 is disposed to overcome the problem of gray scale inversion at a large viewing angle in the vertical viewing angle direction.

Fig. 6A is a cross-sectional view of a first prism sheet or a second prism sheet of a display device according to an embodiment of the invention. Referring to fig. 1 and fig. 6A together, in fig. 1, in order to clearly show the structures of the first prism microstructure 222 and the second prism microstructure 232, fig. 1 only shows one first prism microstructure 222 and one second prism microstructure 232. In the present embodiment, the first prism sheet 220 has a plurality of first prism microstructures 222 extending along a third extending direction E3, wherein an included angle between the third extending direction E3 and the first direction D1 is within a range of 90 ± 20 degrees. The second prism sheet 230 has a plurality of second prism microstructures 232 extending along a fourth extending direction E4, wherein an included angle between the fourth extending direction E4 and the first direction D1 is less than or equal to 20 degrees. In an embodiment, the third extending direction E3 and the fourth extending direction E4 are preferably perpendicular to each other.

In the present embodiment, an included angle between the first extending direction E1 of the light spreading film 250 and the fourth extending direction E4 of the second prism sheet 230 falls within a range of 45 ± 10 degrees.

Specifically, the first prism sheet 220 of the present embodiment includes a substrate 224, and the first prism microstructures 222 are disposed on the substrate 224 on the upper surface 224S1 opposite to the optical plate 212, but the invention is not limited thereto. Furthermore, the first prism microstructure 222 has a plurality of third turning regions 222F. The third turning region 222F is a region where a height difference L' between the first prism microstructure 222 at each local extreme value with respect to the surface 222S of the optical plate 212 and its adjacent local extreme value in the arrangement direction a falls within a range of 0 to 10%, where the height is a distance between the surface 222S of the first prism microstructure 222 and the upper surface 224S1 of the substrate 224. The extending direction of the third turning region 222F is perpendicular to the arrangement direction of the first prism microstructures 222.

In the present embodiment, the ratio of the projection area of the third turning region 222F on the first prism sheet 220 relative to the upper surface 224S1 of the optical plate 212 to the projection area of the first prism microstructures 222 on the upper surface 224S1 of the first prism sheet 220 is greater than or equal to 21% and less than or equal to 25%.

Similarly, the second prism sheet 230 of the embodiment includes a substrate 234, and the second prism microstructures 232 are disposed on the substrate 234 on the upper surface 234S1 opposite to the optical plate 212, but the invention is not limited thereto. Furthermore, the second prism microstructure 232 has a plurality of fourth turning regions 232F. The fourth turning region 232F is a region where a height difference L' in the arrangement direction a between the second prism microstructure 232 at each local extreme value with respect to the surface 232S of the optical plate 212 and its adjacent local extreme value falls within a range of 0 to 10%, where the height is a distance between the surface 232S of the second prism microstructure 232 and the upper surface 234S1 of the base plate 234. The extending direction of the fourth turning region 232F is perpendicular to the arrangement direction of the second prism microstructures 232.

In the present embodiment, the ratio of the projection area of the fourth inflection region 232F on the upper surface 234S1 of the second prism sheet 230 relative to the optical plate 212 to the projection area of the second prism microstructures 232 on the upper surface 234S1 of the second prism sheet 230 is greater than or equal to 21% and less than or equal to 25%.

Fig. 6B is a partially enlarged view of the first prism microstructure or the second prism microstructure of fig. 6A. Referring to fig. 6B, in the present embodiment, the

prism tips

222T and 232T of the first prism microstructure 222 and the second prism microstructure 232 relative to the optical plate 212 can be rounded. Furthermore, the radius of curvature R2 of the prism tip 232T of each second prism microstructure 232 is less than or equal to the radius of curvature R1 of the prism tip 232T of each first prism microstructure 222.

Fig. 7 is a graph of relative luminance values in a horizontal viewing angle direction versus viewing angle when a radius of curvature of a prism tip of a first prism microstructure of a first prism sheet is larger and smaller than a radius of curvature of a prism tip of a second prism microstructure of a second prism sheet at a lowest gray scale in a display device according to an embodiment of the invention. Curve C7 in fig. 7 is that the radius of curvature R1 of the prismatic tip 222T of the first prismatic microstructure 222 is smaller than the radius of curvature R2 of the prismatic tip 232T of the second prismatic microstructure 232, where R1 is 0.5 microns and R2 is 7 microns; curve C8 is where the radius of curvature R1 of the prism tip 222T of the first prism microstructure 222 is greater than the radius of curvature R2 of the prism tip 232T of the second prism microstructure 232, where R1 is 7 microns and R2 is 0.5 microns. Referring to fig. 7, in the display device 10 according to the embodiment of the invention, when the curvature radius R2 of the prism tip 232T of the second prism microstructure 232 is smaller than or equal to the curvature radius R1 of the prism tip 232T of the first prism microstructure 222, the problem of light leakage at a large viewing angle when the display device 10 is at the lowest gray level is improved.

In the present embodiment, the prism refractive index of the second prism sheet 230 is equal to or greater than the prism refractive index of the first prism sheet 220. FIG. 8 is a graph of relative luminance values with respect to viewing angle in a horizontal viewing angle direction when the prism refractive index of the first prism sheet is greater than and less than the prism refractive index of the second prism sheet at the lowest gray level in the display device according to an embodiment of the invention. Curve C9 in fig. 8 illustrates that the prism refractive index of the first prism sheet 220 is 1.65, and the prism refractive index of the second prism sheet 230 is 1.52; the curve C10 illustrates that the prism refractive index of the first prism sheet 220 is 1.52, and the prism refractive index of the second prism sheet 230 is 1.65. Referring to fig. 8, in the display device 10 according to the embodiment of the invention, when the prism refractive index of the second prism sheet 230 is greater than or equal to the prism refractive index of the first prism sheet 220, the problem of light leakage at a large viewing angle when the display device 10 has the lowest gray scale is also improved.

Referring to fig. 6A, in an embodiment, the first prism sheet 220 and the second prism sheet 230 respectively have a first atomizing structure layer 226 and a second atomizing structure layer 236 on the lower surfaces 224S2 and 234S2 facing the optical plate 212, wherein the haze of the second atomizing structure layer 236 is preferably less than or equal to the haze of the first atomizing structure layer 226. Fig. 9 is a graph of relative luminance values in a horizontal viewing angle direction versus viewing angle when the haze of the first atomized structure layer of the first prism sheet is greater than or less than the haze of the second atomized structure layer of the second prism sheet at the lowest gray scale in the display device according to an embodiment of the invention. Curve C11 in fig. 9 illustrates that the haze of the first atomized structure layer 226 is 3% and the haze of the second atomized structure layer 236 is 8%; curve C12 illustrates that the haze of the first atomized structure layer 226 is 8% and the haze of the second atomized structure layer 236 is 3%. Referring to fig. 9, in the display device 10 according to the embodiment of the invention, when the haze of the second atomization structure layer 236 is less than or equal to the haze of the first atomization structure layer 226, the problem of light leakage at a large viewing angle when the display device 10 is at the lowest gray scale is also improved.

Fig. 10A is an example of an outgoing light shape of a display device according to an embodiment of the invention. Fig. 10B is an example of the light-emitting shape of the backlight module of the display device according to the embodiment of the invention. Fig. 10A and 10B illustrate the display device 10 and the backlight module 200 with the first extending direction E1 of the light spreading film 250 at 0 degree in the axial direction, the third direction D3 of the reflective polarizing film 240 at 45 degrees in the axial direction, the fourth extending direction E4 of the second prism sheet 230 at 45 degrees in the axial direction, and the third extending direction E3 of the first prism sheet 220 at 135 degrees in the axial direction. Referring to fig. 10A and 10B, in the display device 10 according to the embodiment of the invention, due to the arrangement of the mode layers of the display device 10, the light-emitting light shape of the backlight module 200 is relatively symmetrical and collimated, and the light shape of the display screen displayed by the display device 10 is also relatively symmetrical.

FIG. 11A is a graph of relative luminance values with respect to viewing angle in the horizontal viewing angle direction at the lowest gray level of a display device according to an embodiment of the present invention. FIG. 11B is a graph of relative luminance values with respect to viewing angle in the vertical viewing angle direction at the lowest gray level of a display device according to an embodiment of the present invention. Curves C13 and C15 in fig. 11A and 11B show that the display device is not provided with a light-diffusing film, and the third direction of the reflective polarizing film is at 45 degrees in the axial direction, the fourth extending direction of the second prism sheet is at 150 degrees in the axial direction, and the third extending direction of the first prism sheet is at 60 degrees in the axial direction; curves C14 and C16 show that the first extending direction E1 of the light spreading film 250 of the display device is 0 degree in the axial direction, the third direction D3 of the reflective polarizing film 240 is 45 degrees in the axial direction, the fourth extending direction E4 of the second prism sheet 230 is 45 degrees in the axial direction, and the third extending direction E3 of the first prism sheet 220 is 135 degrees in the axial direction. Referring to fig. 11A and 11B, in the display device 10 according to the embodiment of the invention, due to the arrangement of the mold layers of the display device 10, the peak values of the vertical viewing angle and the horizontal viewing angle at the large viewing angle of the display device 10 at the lowest gray scale are reduced by 40%, and therefore, the problem of light leakage at the large viewing angle of the vertical viewing angle and the horizontal viewing angle at the lowest gray scale of the display device 10 is effectively improved.

In addition, in the present embodiment, the average gamma value of the image light in the range of 32 to 192 gray-scale values along the 60 degree viewing angle of the liquid crystal module 10 is larger in the horizontal viewing angle direction than in the vertical viewing angle direction.

In summary, in the display device according to an embodiment of the invention, the light spreading film is disposed on the reflective polarizer film, and the films are matched in the display device, so that the light shape of the surface light source provided by the backlight module of the display device is symmetrical and collimated, and the problem of light leakage at the vertical viewing angle and the horizontal viewing angle of the display device at the lowest gray scale is effectively improved. In addition, the display device adopts the two-domain liquid crystal layer, so the luminance performance of the display device is better.

Claims

1. A display device, comprising:

a liquid crystal module, comprising:

a dual domain liquid crystal layer, wherein liquid crystal molecules of the dual domain liquid crystal layer are arranged along a horizontal arrangement direction when no voltage is applied;

a lower polarizer having a penetrating axis along a first direction, wherein an included angle between the first direction and the horizontal arrangement direction is within a range of 45 + -5 degrees; and

an upper polarizer having a transmission axis along a second direction, wherein the lower polarizer, the dual-domain liquid crystal layer and the upper polarizer are arranged in sequence in an arrangement direction; and

a backlight module for providing a surface light source, the backlight module comprising:

a light extraction module, comprising:

an optical plate having a light emergent surface and a light incident surface; and

a light source arranged at one side of the light incident surface of the optical plate;

a first prism sheet;

a second prism sheet;

a reflective polarizing film having a transmission axis along a third direction, wherein an angle between the third direction and the first direction is within a range of 0 + -5 degrees; and

the light diffusion film is provided with a plurality of first microstructures extending along a first extending direction;

the light emitting module, the first prism sheet, the second prism sheet, the reflective polarization membrane, the light diffusion membrane and the liquid crystal module are arranged in sequence in the arrangement direction, light emitted by the light emitting module is emitted through the light emitting surface of the optical plate and then sequentially passes through the first prism sheet, the second prism sheet, the reflective polarization membrane, the light diffusion membrane and the liquid crystal module to form image light.

2. The display device of claim 1, wherein an angle between the second direction of the upper polarizer and the first direction of the lower polarizer is within a range of 90 ± 5 degrees, and the upper polarizer has a plurality of second microstructures along a second extending direction, and an angle between the second extending direction and the horizontal arrangement direction is less than or equal to 20 degrees.

3. The display device of claim 2, wherein the first prism sheet has a plurality of first prism microstructures extending along a third extending direction, wherein an included angle between the third extending direction and the first direction is within a range of 90 ± 20 degrees.

4. The display device of claim 3, wherein the second prism sheet has a plurality of second prism microstructures extending along a fourth extending direction, wherein an included angle between the fourth extending direction and the first direction is less than or equal to 20 degrees.

5. The display device of claim 4, wherein an angle between the first extending direction of the light spreading film and the fourth extending direction of the second prism sheet falls within a range of 45 ± 10 degrees.

6. The display device according to claim 5, wherein the first microstructures, the second microstructures, the first prism microstructures and the second prism microstructures have a plurality of first turning regions, a plurality of second turning regions, a plurality of third turning regions and a plurality of fourth turning regions, respectively, and the first turning regions, the second turning regions, the third turning regions and the fourth turning regions are regions where a height difference along the arrangement direction between each local extreme value and an adjacent local extreme value of the first microstructures relative to the surface of the optical plate falls within a range of 0 to 10%;

the extending directions of the first turning regions, the second turning regions, the third turning regions and the fourth turning regions are respectively perpendicular to the arrangement directions of the first microstructures, the second microstructures, the first prism microstructures and the second prism microstructures.

7. The display device of claim 6, wherein a ratio of a projected area of the light diffusing film relative to the upper surface of the optical plate to a projected area of the first microstructures on the upper surface of the light diffusing film is greater than or equal to 30% and less than or equal to 60%.

8. The display device of claim 6, wherein a ratio of a projected area of the second turning regions on the upper polarizer relative to the upper surface of the optical plate to a projected area of the second microstructures on the upper surface of the upper polarizer is greater than or equal to 85% and less than or equal to 93%.

9. The display device of claim 6, wherein a ratio of a projected area of the third turning regions on the upper surface of the first prism sheet relative to the optical plate to a projected area of the first prism microstructures on the upper surface of the first prism sheet is greater than or equal to 21% and less than or equal to 25%.

10. The display device of claim 6, wherein a ratio of a projected area of the fourth turning regions on the upper surface of the second prism sheet relative to the optical plate to a projected area of the second prism microstructures on the upper surface of the second prism sheets is greater than or equal to 21% and less than or equal to 25%.

11. The display device of claim 1, wherein the first microstructures have an average height difference of L, an average pitch of P, and 4% L/P < 25%.

12. The display device as claimed in claim 4, wherein a radius of curvature of each second prism microstructure at the prism tip relative to the optical plate is less than or equal to a radius of curvature of each first prism microstructure at the prism tip relative to the optical plate.

13. The display device of claim 1, wherein a prism refractive index of the second prism sheet is equal to or greater than a prism refractive index of the first prism sheet.

14. The display device of claim 1, wherein the first prism sheet and the second prism sheet have a first atomizing structure layer and a second atomizing structure layer on the lower surface facing the optical plate, respectively, and the haze of the second atomizing structure layer is less than or equal to the haze of the first atomizing structure layer.

15. The display device as claimed in claim 1, wherein the optical plate is a light guide plate, and the light exiting surface is adjacent to the light incident surface.

16. The display device as claimed in claim 1, wherein the optical plate is a diffuser plate, and the light exiting surface is opposite to the light incident surface.

17. The display device of claim 1, wherein the backlight module further comprises a quantum dot layer disposed on the optical plate, and the light source comprises a blue light source.

18. The display device of claim 17, wherein the quantum dot layer is disposed between the optical plate and the first prism sheet.

19. The display apparatus of claim 1, wherein an average gamma value of the image light in a range of 32 to 192 gray-scale values along a 60 degree viewing angle of the liquid crystal module is greater in a horizontal viewing angle direction than in a vertical viewing angle direction.

20. The display apparatus of claim 2, wherein the image light has a gamma average in a range of 32 to 192 gray-scale values along a 60 degree viewing angle of the liquid crystal module that is greater in a horizontal viewing angle direction than in a vertical viewing angle direction.