KR20080088867A - Light emission device and display device provided with the same - Google Patents

Abstract

The present invention relates to a light emitting device and a display device having the same. A light emitting device according to an embodiment of the present invention includes a first substrate and a second substrate disposed to face each other, an electron emission unit provided on the first substrate, a light emitting unit provided on the second substrate, a first substrate and a second substrate The spacer includes a spacer disposed between and supporting the first substrate and the second substrate. Electrons emitted from the electron emitting unit collide with the light emitting unit to form a light emitting region in which light is emitted, and the light emitting unit includes one or more protruding members positioned closer to the spacer than the center of the light emitting region.

Description

LIGHT EMISSION DEVICE AND DISPLAY DEVICE PROVIDED WITH THE SAME

1 is a partially exploded perspective view of a light emitting device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

3 is a partial perspective view of a light emitting unit included in the light emitting device of FIG. 1.

4 is a partial perspective view of another light emitting unit.

5 is an exploded perspective view of a display device according to an exemplary embodiment.

The present invention relates to a light emitting device and a display device having the same, and more particularly, to a light emitting device having uniform luminance and a display device having the same.

As a general electron emission element, a field emitter array (FEA) type is known.

The FEA type electron emission element includes an electron emission portion and a cathode electrode and a gate electrode as driving electrodes for controlling electron emission of the electron emission portion. Here, the electron emitting portion may be a material having a low work function or a high aspect ratio, for example, a tip structure having a sharp tip, mainly made of molybdenum (Mo) or silicon (Si), or carbon nanotubes and graphite. And carbon-based materials such as diamond-like carbon may be used, which readily emit electrons by an electric field in vacuum.

The electron-emitting device is formed in an array on one substrate to form an electron emission device, and the electron-emitting device is combined with another substrate having a light-emitting unit composed of a fluorescent layer and an anode electrode or the like to provide a light emitting device ( an electron emission display).

A conventional surface light source device emits electrons at an electron emission portion provided on a rear substrate, and emits visible light through the process of exciting these fluorescent layers provided on the front substrate. Such a surface light source device has low power consumption, is advantageous for large size, and has a complicated optical member configuration compared with the case of using a Cold Cathode Fluorescent Lamp (CCFL) or a Light Emitting Diode (LED). There is an advantage.

However, in the surface light emitting device that excites the fluorescent layer with electrons and emits visible light, the electron beam is excessively focused by a high voltage applied to the anode electrode, so that there is a problem in that a non-light emitting region is exposed to excite the fluorescent layer.

In addition, in the conventional surface light emitting device, the entire light emitting surface emits light with a constant luminance when driving the liquid crystal display device, so that it is difficult to meet the image quality improvement required for the liquid crystal display device, for example, the image quality improvement to increase the dynamic contrast. have.

Accordingly, an aspect of the present invention is to provide a light emitting device capable of minimizing a non-light emitting area and increasing light emission efficiency and a display device using the same as a surface light source.

A light emitting device according to an embodiment of the present invention includes a first substrate and a second substrate disposed opposite to each other, an electron emission unit provided on the first substrate, a light emitting unit provided on the second substrate, and between the first substrate and the second substrate. And a spacer disposed at and spaced apart from each other to support the first substrate and the second substrate. Here, a light emitting region in which light is emitted by electrons emitted from the electron emitting unit colliding with the light emitting unit is formed, and the light emitting unit includes one or more protruding members positioned closer to the spacer than the center of the light emitting region.

The one or more protruding members may include a plurality of protruding members, and the plurality of protruding members may be arranged between the spacer and the center of the light emitting area. Heights of two or more protruding members of the plurality of protruding members may be different. The plurality of protruding members may be greater in height as they are closer to the spacer.

In addition, the one or more protruding members may include a plurality of protruding members, and the plurality of protruding members may be arranged along a diagonal direction of the light emitting area.

The spacer is formed in the form of a partition wall having a wall surface, one or more protruding members may include a plurality of protruding members, and the plurality of protruding members may be disposed next to and adjacent to the wall surface. The resistance of the protruding member may be 10 ⁴ kPa to 10 ⁸ kPa. The protruding member may be manufactured by coating metal particles on a glass base material or a ceramic base material.

On the other hand, the display device according to an embodiment of the present invention includes a display panel for displaying an image, and a light emitting device for providing light to the display panel. The light emitting device may include a first substrate and a second substrate disposed opposite to each other, an electron emission unit provided on the first substrate, a light emitting unit provided on the second substrate, and a first substrate and a second substrate disposed between the first substrate and the second substrate. A spacer spaced apart from and supporting the second substrate, wherein a light emitting region in which light is emitted by electrons emitted from the electron emitting unit colliding with the light emitting unit is formed, and the light emitting unit has one or more protrusions located closer to the spacer than the center of the light emitting region; Member.

The one or more protruding members may include a plurality of protruding members, and the plurality of protruding members may be arranged between the spacer and the center of the light emitting area. Heights of two or more protruding members of the plurality of protruding members may be different. The plurality of protruding members may be greater in height as they are closer to the spacer.

DETAILED DESCRIPTION Embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art can easily understand, the embodiments described below may be modified in various forms without departing from the concept and scope of the present invention. Where possible, the same or similar parts are represented using the same reference numerals in the drawings.

When a portion is referred to as being "above" another portion, it may be just above the other portion or may be accompanied by another portion in between. In contrast, when one part is mentioned "right over" another part, no other part is intervened.

It is to be understood that the terms first, second and third are used to describe various parts, components, regions, layers and / or sections, but are not limited to these. These terms are only used to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, the first portion, component, region, layer or section described below may be referred to as the second portion, component, region, layer or section without departing from the scope of the invention.

The terminology used herein is for reference only to specific embodiments and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the term "comprising" embodies a particular characteristic, region, integer, step, operation, element, and / or component, and other specific characteristics, region, integer, step, operation, element, component, and / or group. It does not exclude the presence or addition of.

Terms indicating relative spaces such as "below" and "above" may be used to more easily describe the relationship between different parts of one part shown in the drawings. These terms are intended to include other meanings or operations of the device in use with the meanings intended in the figures. For example, when the device in the figure is reversed, any parts described as being "below" of other parts are described as being "above" other parts. Thus, the exemplary term "below" encompasses both up and down directions. The device can be rotated 90 degrees or at other angles, the terms representing relative space being interpreted accordingly.

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. Commonly defined terms used are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted as ideal or very formal meaning unless defined.

In the embodiment of the present invention, the light emitting device includes all devices capable of recognizing that light is emitted when viewed from the outside. Therefore, the devices of all displays that display information by displaying symbols, letters, numbers, and images, are also included in the light emitting device. In addition, the light emitting device may be used as a light source for providing light to the light receiving display panel.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a partially exploded perspective view of a light emitting device according to an embodiment of the present invention.

Referring to FIG. 1, the light emitting device includes a first substrate 10 and a second substrate 12 that are disposed to be parallel to each other at predetermined intervals. The 1st board | substrate 10 and the 2nd board | substrate 12 are joined by the sealing member (not shown) arrange | positioned at the edge, and comprise the vacuum container which has an internal space. The vessel is evacuated to a vacuum of approximately 10 ⁻⁶ Torr to constitute a vacuum vessel consisting of the first substrate 10, the second substrate 12, and the sealing member.

The first substrate 10 opposite to the second substrate 12 is provided with an electron emission unit 100 in which an array of electron emission elements is arranged, and the second substrate 12 opposite to the first substrate 10 is fluorescent. A light emitting unit 110 is provided that includes a layer 22, an anode electrode 24, and the like. The first substrate 10 provided with the electron emission unit 100 and the second substrate 12 provided with the light emitting unit 110 are combined to form a light emitting device.

The vacuum vessel of the above-described configuration may include other electrons including field emission array (FEA) type, surface conduction emission (SCE) type, metal-insulating layer-metal (MIM) type, and metal-insulating layer-semiconductor (MIS) type. Since the present invention can be applied to an emission type display, a field emission array (FEA) type light emitting device will be described below in detail.

First, cathode electrodes 14 are formed on the first substrate 10 in a stripe pattern along the y-axis direction on the first substrate 10. The first insulating layer 16 is formed on the first substrate 10 while covering the cathode electrodes 14, and the gate electrodes 18 are orthogonal to the cathode electrodes 14 on the first insulating layer 16. Is formed in a stripe pattern along the x-axis direction.

As a result, an intersection region of the cathode electrode 14 and the gate electrode 18 is formed, and this intersection region can constitute one unit pixel. Electron emitters 20 are formed in each unit pixel on the cathode electrodes 14.

The electron emission unit 20 arranged in the above structure is made of materials emitting electrons when a electric field is applied in a vacuum, such as a carbon-based material or a nanometer (nm) size material. That is, the electron emission unit 20 is composed of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbon, fullerene (C ₆₀ ), silicon nanowires, and combinations thereof. On the other hand, the electron emission portion may be formed of a tip structure having a pointed tip mainly made of molybdenum (Mo) or silicon (Si).

As shown in the enlarged source of FIG. 1, the first insulating layer 16 and the gate electrodes 18 respectively have a first opening 161 and a second opening 181 corresponding to the electron emission section 20. Is formed to expose the electron emission unit 20 on the first substrate 10. That is, the electron emission part 20 is formed on the cathode electrode 14 and is exposed to the outside through the first opening 161 and the second opening 181. Although the electron emission unit 20 is illustrated in the form of a cylinder in the present embodiment, the shape thereof is not necessarily limited to the illustrated example.

Next, the fluorescent layer 22 is formed on one surface of the second substrate 12 facing the first substrate 10. The fluorescent layer 22 may be made of a white fluorescent layer. In addition, the fluorescent layer 22 may be formed in the entire effective region of the second substrate 12 or may be formed in a predetermined pattern so that one white fluorescent layer is positioned in each unit pixel region.

On the other hand, the fluorescent layer may be composed of a combination of red, green and blue fluorescent layers, these fluorescent layers may be divided into a predetermined pattern in one pixel area. 1 and 2 show that a white fluorescent layer is located throughout the effective region of the second substrate.

An anode electrode 24 made of a metal such as aluminum (Al) is formed on the fluorescent layer 22. The anode electrode 24 receives a high voltage required for electron beam acceleration from the outside, for example, a voltage of 10 kV to 20 kV to maintain the fluorescent layer 22 in a high potential state, and displays the first substrate of visible light emitted from the fluorescent layer 22. Visible light emitted toward 10 is reflected toward the second substrate 12 to improve luminance. Here, the fluorescent layer 22 and the anode electrode 24 are sequentially stacked on the second substrate 12 so that the fluorescent layer 22 is adjacent to the second substrate 12. Accordingly, since the anode electrode 24 does not interfere with the light emitted from the fluorescent layer 22, the anode electrode 24 can be formed of an opaque metal having good electrical conductivity.

However, it is also possible to change the position of the fluorescent layer and the anode electrode for lamination. That is, when the anode electrode is made of a transparent conductive film such as indium tin oxide (ITO), the transparent anode electrode may be positioned between the second substrate and the fluorescent layer. Moreover, the transparent conductive film mentioned above can be used as an anode electrode, and a metal film can also be further formed here.

In addition, spacers 26 are disposed between the first substrate 10 and the second substrate 12 to maintain a constant gap between the two substrates 10 and 12 against the atmospheric pressure applied to the vacuum container. . 1 shows one spacer for convenience. The spacer 26 is mainly made of a dielectric such as ceramic so that the driving electrodes 14 and 18 of the first substrate 10 and the driving electrode 24 of the second substrate 12 are not shorted through the spacer 26. Is produced.

FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1.

In the conventional light emitting device, the spacer is exposed inside the vacuum vessel in which the flow of electrons continuously occurs and collides with the electrons emitted from the electron emission portion. This collision causes secondary electrons to be emitted from the spacer. This leads to charging of the spacers and causes distortion of the path of the electron beam. In order to solve this problem, the protruding member 28 is disposed in the fluorescent layer 22 of the second substrate 12.

The protruding member 28 is disposed close to the spacer 26 to distort the path of the electron beam toward the spacer 26 (see the solid line in FIG. 2) by distorting the electric field formed around the spacer 26 (see dotted line in FIG. 2). Change it. Specifically, the protruding members 28 are arranged between the spacer 26 and the center of the light emitting area D, but located closer to the spacer 26 than the center of the light emitting area D. FIG. Since the protruding member 28 is located closer to the spacer 26, the electric field can be distorted more efficiently.

3 and 4 show light emitting units included in the light emitting device according to the present embodiment. 3 shows a mold-shaped spacer, and FIG. 4 shows a partition-shaped spacer.

Referring to FIG. 3, the protruding member 28 is disposed outside the light emitting area and arranged around the spacer 26 along the diagonal direction of the light emitting area. Referring to Fig. 4, the protruding members 28 'are arranged side by side adjacent to the wall surface of the partition 26' shaped partition.

The protruding member 28 has a cylindrical or polygonal column shape, and the height h of the protruding member 28 is 1 mm or less. Further, when the cross section of the protruding member 28 is circular, the diameter of the circle is 100 μm or less, and when the cross section of the protruding member 28 is polygonal, the maximum width of the polygon is also 100 μm or less.

On the other hand, the protruding member may have a horn shape whose cross section is circular or polygonal. Also in this case, the height of the protruding member is preferably 1 mm or less, and its width is preferably 100 μm or less. If the protruding member is horn shaped, that is, the sharp end of the protruding member is more advantageous for distorting the electric field because electrons are concentrated as compared to the flat case.

Each of the protruding members 28 and 28 'arranged in the above-described manner is formed with different protruding heights h protruding from the fluorescent layer 22. At this time, it is preferable that the protruding members 28 and 28 'are closer to the spacers 26 and 26', and the height thereof is larger. As the heights of the protruding members 28 and 28 ′ increase, the distortion of the electric field occurs as shown in FIG. 2, and the path of the electron beam changes rapidly. Since the electron beam is bent well, the path of the electron beam toward the spacer can be easily controlled.

The protruding members 28, 28 'are made of a low resistance material or a structure coated with the material so as to distort the electric field. The resistance of the protruding members 28, 28 'is preferably 10 ⁴ kPa to 10 ⁸ kPa, and such materials include, for example, glass or ceramics, and are coated with metals, metal oxides or metal nitrides on their surfaces. have. CuN, AlN, PtAlN, or the like may be used as the metal nitride.

However, the present invention is not limited thereto, and any material that satisfies the above resistance range may be used as the protruding member. For example, glass paste, nickel paste, etc. containing metal particles can also be used.

If the resistance of the protruding members 28 and 28 'is less than 10 ⁴ dB, excessive distortion of the electric field may occur and the electron beam may be focused to the center of the emission area. In addition, if the resistance of the protruding members 28, 28 'exceeds 10 ⁸ kPa, it may be unsuitable for distorting the electric field due to the large resistance.

Referring to FIG. 2 again, the above-described light emitting device forms a plurality of unit pixels by using a combination of cathode electrodes 14 and gate electrodes 18. A predetermined voltage is supplied from the outside to the cathode electrodes 14, the gate electrodes 18, and the anode electrode 24 to drive the light emitting device. For example, any one of the cathode electrodes 14 and the gate electrodes 18 receives a scan driving voltage to serve as scan electrodes, and the other electrodes receive a data driving voltage to serve as data electrodes. In addition, the anode electrode 24 receives a voltage required for electron beam acceleration, for example, a positive DC voltage of 10 kV to 20 kV.

As a result, an electric field is formed around the electron emission unit 20 in the unit pixels in which the voltage difference between the cathode electrode 14 and the gate electrode 18 is greater than or equal to the threshold, thereby emitting electrons from the electron emission unit 20. The emitted electrons are attracted by the high voltage applied to the anode electrode 24 to impinge on the corresponding fluorescent layer 22 to cause the fluorescent layer 22 to emit light.

In the above-described process, the electric field formed between the first substrate 10 and the second substrate 12 is distorted as shown by the dotted line in FIG. 2 by the protruding member 28 protruding from the fluorescent layer 22 and perpendicular to the electric field. The electron beam going straight in the direction shown in the figure is curved sharply around the spacer 26 so that the electrons e- colliding with the spacer 26 are reduced.

In addition, since the protruding member 28 absorbs arcing current generated inside the vacuum container in addition to distorting the electric field, the protruding member 28 can prevent the fluorescent layer 22 and the anode electrode 24 from being damaged by arc discharge. .

5 is an exploded perspective view of a display device having a light emitting device according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the display device 1 includes a light emitting device 30 and a display panel 40 positioned in front of the light emitting device 30. A diffusion plate 50 may be disposed between the light emitting device 30 and the display panel 40 to uniformly diffuse the light emitted from the light emitting device 30 and provide the light to the display panel 40. The diffusion plate 50 and the light emitting device 30 are spaced apart from each other by a predetermined distance. The top chassis 52 and the bottom chassis 54 are positioned at the front of the display panel 40 and the rear of the light emitting device 30 to fix internal components.

The display panel 40 is formed of a liquid crystal display panel or another light receiving display panel. Hereinafter, the case where a display panel is a liquid crystal display panel as an example is demonstrated.

The display panel 40 includes a TFT panel 42 including a plurality of thin film transistors (TFTs), a color filter panel 44 positioned on the TFT panel, and a liquid crystal layer (not shown). City). Polarizers (not shown) are attached to the upper portion of the color filter panel 44 and the lower portion of the TFT panel 42 to polarize light passing through the display panel 40.

The TFT panel 42 is a transparent glass substrate on which a thin film transistor on a matrix is formed, a data line is connected to a source terminal, and a gate line is connected to a gate terminal. In the drain terminal, a pixel electrode made of a transparent conductive film as a conductive material is formed.

When electrical signals are input from the printed circuit boards 46 and 48 to the gate line and the data line, respectively, electrical signals are input to the gate terminal and the source terminal of the TFT, and the TFT is turned on in response to the input of these electrical signals. Alternatively, the signal is turned off to output an electrical signal necessary for pixel formation to the drain terminal.

The color filter panel 44 is a panel in which RGB pixels, which are color pixels in which a predetermined color is expressed while light passes, are formed by a thin film process, and a common electrode made of a transparent conductive film is coated on the entire surface.

When power is applied to the gate terminal and the source terminal of the TFT and the thin film transistor is turned on, an electric field is formed between the pixel electrode and the common electrode of the color filter panel 44. By this electric field, the arrangement angle of the liquid crystal injected between the TFT panel 42 and the color filter panel 44 is changed, and the light transmittance is changed for each pixel according to the changed arrangement angle.

The printed circuit boards 46 and 48 of the display panel 40 are connected to the respective driving IC packages 461 and 481. In order to drive the display panel 40, the gate printed circuit board 46 transmits a gate driving signal, and the data printed circuit board 48 transmits a data driving signal.

The light emitting device 30 forms fewer pixels than the display panel 40 so that one pixel of the light emitting device 30 corresponds to two or more pixels of the display panel 40. Each pixel of the light emitting device 30 may emit light corresponding to the highest gray level among the pixels of the display panel 40 corresponding thereto, and the light emitting device 30 may express a gray level of 2 to 8 bits for each pixel. have.

For convenience, a pixel of the display panel 40 is called a first pixel, a pixel of the light emitting device 30 is called a second pixel, and a plurality of first pixels corresponding to one second pixel is called a first pixel group. .

In the driving process of the light emitting device 30, a signal controller (not shown) controlling the display panel 40 detects the highest gray level among the first pixels of the first pixel group, and emits the second pixel according to the detected gray level. The method may include calculating a grayscale required for the digital signal, converting the grayscale to digital data, and generating a driving signal of the light emitting device using the digital data. The driving signal of the light emitting device 30 includes a scan driving signal and a data driving signal.

The printed circuit boards 32 and 34 of the light emitting device 30 are connected to the driving IC packages 321 and 341. In order to drive the light emitting device 30, the printed circuit boards 32 and 34 transmit scan driving signals and data driving signals. The scan drive signal is applied to one of the above-described cathode electrode 14 (shown in FIG. 1) and the gate electrode 18 (shown in FIG. 1), and the data drive signal is applied to the other electrode.

The second pixel of the light emitting device 30 emits light with a predetermined gray level in synchronization with the first pixel group when an image is displayed in the corresponding first pixel group. The light emitting device 30 may form 2 to 99 pixels in a row direction and a column direction. When the number of pixels of the light emitting device in the row direction and the column direction exceeds 99, the driving of the light emitting device may be complicated, and the cost may be increased for manufacturing the driving circuit.

In this way, the light emitting device independently controls the light emission intensity of each pixel to provide light of appropriate intensity to the display panel pixels corresponding to each pixel. Therefore, the display device of the present embodiment can increase the dynamic contrast of the screen and can realize a clearer picture quality.

In addition, the light emitting device according to the present embodiment can suppress the charging of the spacer surface by controlling the path of the electron beam toward the spacer using the protruding member. Minimizing the drag phenomenon of the electron beam with respect to the spacer can uniformly emit the fluorescent layer corresponding to the electron emission portion. Therefore, since the luminance of the light emitting device is improved, the visibility of the display device can be improved.

The light emitting device according to the embodiment of the present invention, using a protruding member to a spacer By changing the path of the electron beam to be directed, charging of the spacer can be suppressed. Therefore Therefore, since the fluorescent layer emits light uniformly and improves the luminance of the light emitting surface, the display quality of the display device using the above-described light emitting device as a light source can be improved.

Although the present invention has been described above, it will be readily understood by those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the claims set out below.

Claims (12)

A first substrate and a second substrate disposed to face each other; An electron emission unit provided on the first substrate; A light emitting unit provided on the second substrate; And A spacer disposed between the first substrate and the second substrate and spaced apart from each other to support the first substrate and the second substrate Including, And a light emitting region in which light is emitted by electrons emitted from the electron emitting unit colliding with the light emitting unit, wherein the light emitting unit includes one or more protruding members positioned closer to the spacer than the center of the light emitting region. According to claim 1, The at least one protruding member comprises a plurality of protruding members, And the plurality of protruding members are arranged between the spacer and the center of the light emitting area. The method of claim 2, A light emitting device in which the heights of two or more protruding members of the plurality of protruding members are different. The method of claim 3, wherein The plurality of protruding members closer to the spacer, the height of the light emitting device. According to claim 1, The at least one protruding member includes a plurality of protruding members, and the plurality of protruding members are arranged along a diagonal direction of the light emitting area. According to claim 1, The spacer is formed in the form of a partition wall having a wall surface, wherein the at least one protruding member includes a plurality of protruding members, the plurality of protruding members are disposed in parallel with the wall surface. According to claim 1, And a resistance of the protruding member is 10 ⁴ kPa to 10 ⁸ kPa. According to claim 1, The protruding member is a light emitting device manufactured by coating metal particles on a glass base material or a ceramic base material. A display panel displaying an image; And A light emitting device that provides light to the display panel Including, The light emitting device, A first substrate and a second substrate disposed to face each other; An electron emission unit provided on the first substrate; A light emitting unit provided on the second substrate; And A spacer disposed between the first substrate and the second substrate and spaced apart from each other to support the first substrate and the second substrate Including, And a light emitting region in which light is emitted by electrons emitted from the electron emitting unit colliding with the light emitting unit, wherein the light emitting unit includes one or more protruding members positioned closer to the spacer than the center of the light emitting region. The method of claim 9, The at least one protruding member comprises a plurality of protruding members, And the plurality of protruding members are arranged between the spacer and the center of the light emitting area. The method of claim 9, A display device with different heights of two or more protruding members among the plurality of protruding members. The method of claim 9, The height of the plurality of protruding members is greater as the spacers are closer to the spacers.

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