KR100766950B1 - Light emission device and display device - Google Patents

Abstract

A light emitting device and a display device are provided to achieve uniform brightness over an entire light emitting surface by installing point light sources outside the second substrate and removing a portion where light is not emitted by a spacer. A vacuum container includes a first substrate(12), a second substrate(14), and a sealing member. An electron emitting unit is provided at one surface of the first substrate and emits an electron. A light emitting unit is provided at an inner surface of the second substrate facing the first substrate and emits visible light by the electron. A plurality of spacers is installed between the first substrate and the second substrate. A plurality of point light sources(36) is installed at an outer surface of the second substrate corresponding to the spacer mounting positions. The point light sources are light emitting diodes.

Description

Light Emitting Device and Display {LIGHT EMISSION DEVICE AND DISPLAY DEVICE}

1 is a partial cross-sectional view of a light emitting device according to an embodiment of the present invention.

2 is a partially exploded perspective view illustrating an effective area of a light emitting device according to an embodiment of the present invention.

3 is a plan view of a second substrate showing a spacer mounting position in a light emitting device according to an exemplary embodiment of the present invention.

4 is a plan view of a second substrate of a light emitting device according to an embodiment of the present invention.

5 is a partially enlarged cross-sectional view of a light emitting diode element and a wiring part of a light emitting device according to an exemplary embodiment of the present invention.

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device and a display device, and more particularly, to a light emitting device capable of increasing luminance uniformity of an entire light emitting surface and a display device using the light emitting device as a light source.

Liquid crystal display devices are known as light-receiving display devices in which a light source is required. The liquid crystal display device includes a display panel including a liquid crystal layer and a polarizing plate, and a light emitting device that provides light to the display panel, and the display panel receives light emitted from the light emitting device and converts the light into the action of the liquid crystal layer and the polarizing plate. By transmitting or blocking, a predetermined image is realized.

Recently, a CCFL method using a cold cathode fluorescent lamp (CCFL), a line light source, and a light emitting diode (LED), a point light source, are referred to as 'LED'. As a light emitting device to replace the LED method, a surface light emitting device using a cold cathode electron source has been developed.

The surface light emitting device emits electrons at the electron emission section provided on the rear substrate, and excites the fluorescent layer provided on the front substrate with the electrons to emit visible light. Compared to the CCFL method and the LED method, such a surface light emitting device has advantages in simplifying the optical member configuration, low power consumption, and advantageous in large size.

However, in the conventional surface light emitting device, since spacers for supporting the compressive force must be installed in the vacuum container, there is a problem in that the spacer region in the light emitting surface remains as a non-light emitting portion. Therefore, the conventional surface light emitting device has to have a diffuser plate having a low light transmittance on the front surface in order to remove the non-light emitting portion, and as a result, the light efficiency is deteriorated.

In addition, the conventional surface light emitting device is difficult to meet the image quality improvement required for the display device, for example, to improve the dynamic contrast, since the entire light emitting surface is configured to display the same brightness when the display device is driven. There is.

Accordingly, the present invention is to solve the above problems, the present invention is to provide a light emitting device that can increase the luminance uniformity of the entire light emitting surface without using a diffuser plate and a display device using the light emitting device as a light source.

The present invention also provides a light emitting device capable of dividing a light emitting surface into a plurality of areas and independently controlling the light emission intensity for each divided area, and a display device using the light emitting device as a light source.

The light emitting device according to the present invention includes a vacuum container including a first substrate, a second substrate, and a sealing member, an electron emission unit provided on one surface of the first substrate, and emitting electrons, and a second substrate facing the first substrate. A light emitting unit provided on an inner surface of the light emitting unit to emit visible light by electrons, a plurality of spacers disposed between the first substrate and the second substrate, and a plurality of point light sources disposed on the outer surface of the second substrate corresponding to the spacer mounting position Include them.

The point light sources may be made of light emitting diode elements. The light emitting device may further include a wiring unit electrically connected to the point light sources along one direction of the second substrate, and the wiring unit may be formed of one of a transparent electrode and a fine wire electrode.

The electron emission unit includes scan electrodes and data electrodes formed along a direction crossing each other while maintaining an insulation state on the first substrate, and electron emission parts electrically connected to any one of the scan electrode and the data electrode. can do.

The display device according to the present invention includes a display panel for displaying an image and a light emitting device having the above-described configuration for providing light to the display panel.

When the display panel includes the first pixels, the light emitting device may have a smaller number of second pixels than the first pixels, and may independently control the light emission intensity for each second pixel. The display panel may be a liquid crystal 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 partial cross-sectional view of a light emitting device according to an embodiment of the present invention, and FIG. 2 is a partially exploded perspective view showing an effective area of a light emitting device according to an embodiment of the present invention.

1 and 2, the light emitting device 10 according to the present exemplary embodiment includes a first substrate 12 and a second substrate 14 that are disposed to face each other in parallel at predetermined intervals. Sealing members 16 are disposed on the edges of the first substrate 12 and the second substrate 14 to bond the two substrates, and the inner space is evacuated with a vacuum of approximately 10 ⁻⁶ Torr so that the first substrate 12 The second substrate 14 and the sealing member 16 constitute a vacuum container.

The first substrate 12 and the second substrate 14 may be divided into an effective region contributing to the actual visible light emission and an ineffective region surrounding the effective region. An electron emission unit 18 for emitting electrons is provided in an effective area of the inner surface of the first substrate 12, and a light emitting unit 20 for emitting visible light is provided in an effective area of the inner surface of the second substrate 14.

The electron emission unit 18 may be of any one of a field emission array type, a surface-conducting emission type, a metal-insulating layer-metal type, and a metal-insulating layer-semiconductor type. 1 and 2 illustrate the field emission array type as an example, which is intended to illustrate the present invention, but the present invention is not limited thereto.

The electron emission unit 18 includes first electrodes 24 and second electrodes 26 and first electrodes 24 formed in a stripe pattern along a direction crossing each other with the insulating layer 22 therebetween, and the first electrodes 24. ) And electron emitters 28 electrically connected to any one of the second electrodes 26.

When the electron emission portion 28 is formed on the first electrode 24, the first electrode 24 becomes a cathode electrode for supplying current to the electron emission portion 28, and the second electrode 26 is a cathode electrode. An electric field is formed by the voltage difference between and the gate electrode is used to induce electron emission. On the contrary, when the electron emission part 28 is formed in the 2nd electrode 26, the 2nd electrode 26 will be a cathode electrode and the 1st electrode 24 will be a gate electrode.

One of the first electrode 24 and the second electrode 26, an electrode mainly positioned in parallel with the row direction of the light emitting device 10 (eg, the second electrode 26) receives a scan driving voltage. It functions as a scan electrode, and another electrode, mainly an electrode (e.g., the first electrode 24) positioned in parallel with the column direction of the light emitting device 10, receives a data driving voltage and functions as a data electrode.

In the drawing, openings 261 and 221 are formed in the second electrode 26 and the insulating layer 22 at each intersection region of the first electrode 24 and the second electrode 26, so that a part of the surface of the first electrode 24 is formed. Is exposed, and the electron emission part 28 is positioned on the first electrode 24 inside the insulating layer opening 221. The position and shape of the electron emission unit 28 is not limited to the illustrated example and can be variously modified.

The electron emission unit 28 may be formed of materials emitting electrons when an electric field is applied, such as a carbon-based material or a nanometer-sized material. The electron emission unit 28 may include, for example, a material selected from the group consisting of carbon nanotubes, graphite, graphite nanofibers, diamonds, diamond-like carbons, fullerenes (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).

In the above structure, one intersection area of the first electrode 24 and the second electrode 26 corresponds to one pixel area of the light emitting device 10, or two or more crossing areas are one pixel area of the light emitting device 10. It can correspond to. In the second case, two or more first electrodes 24 and / or two or more second electrodes 26 positioned in one pixel area are electrically connected to each other to receive the same driving voltage.

Next, the light emitting unit 20 includes a fluorescent layer 30 and an anode electrode 32 positioned on one surface of the fluorescent layer 30. The fluorescent layer 30 may be formed of a white fluorescent layer, and may be formed in the entire effective area of the second substrate 14 or may be divided and disposed in a predetermined pattern such that one white fluorescent layer is positioned in each pixel area.

On the other hand, the fluorescent layer 30 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 illustrate a case where a white fluorescent layer is positioned over the entire effective area of the second substrate 14.

The anode electrode 32 may be formed of a metal film such as aluminum covering the surface of the fluorescent layer 30. The anode electrode 32 is an acceleration electrode for attracting an electron beam to maintain the fluorescent layer 30 in a high potential state by applying a high voltage and radiate toward the first substrate 12 of visible light emitted from the fluorescent layer 30. Visible light is reflected toward the second substrate 14 to increase the luminance of the light emitting surface.

In addition, spacers 34 are disposed between the first substrate 12 and the second substrate 14 to support the compressive force applied to the vacuum container and to keep the distance between the two substrates constant. The spacer 34 may be positioned outside the cross region of the first electrode 24 and the second electrode 26, and may be positioned between the second electrodes 26 to correspond to a portion between the first electrodes 24. have.

The spacer 34 may be formed in various shapes such as square pillars, circular pillars, and rods, and may be made of various materials such as glass, ceramics, tempered glass, and glass-ceramic mixtures. 1 and 2 illustrate one rectangular columnar spacer 34 for convenience.

In the present exemplary embodiment, a plurality of point light sources 36 are disposed on the outer surface of the second substrate 14 corresponding to the mounting portion of the spacer 34 to remove the non-light emitting region by the spacer 34. 3 is a plan view of a second substrate shown for explaining a spacer mounting position, and FIG. 4 is a plan view of a second substrate showing a state in which point light sources are installed.

3 and 4, the spacers 34 are positioned side by side in the row direction and the column direction of the second substrate 14 at a predetermined distance from each other, and occupy a portion of the fluorescent layer 30. Therefore, the region where the spacer 34 is installed remains as the non-light emitting region when the light emitting device 10 is driven. Therefore, the point light sources 36 are installed at the mounting positions of the spacers 34 on the outer surface of the second substrate 14 to remove the non-light emitting area, and serve to increase the luminance uniformity of the light emitting surface.

The point light source 36 may be formed of a light emitting diode element. The point light source 36 may be provided with a current necessary for light emission through the wiring unit 38 positioned along one direction of the second substrate 14, and may be predetermined when driving the light emitting device 10. It emits light with brightness. The wiring unit 38 may be formed of a transparent electrode such as indium tin oxide (ITO) or a fine wire electrode.

5 is an enlarged cross-sectional view of a light emitting diode element and a wiring part, wherein the light emitting diode element includes a chip die 42 in which the light emitting diode chip 40 is installed, and a transparent protective material 44 covering and protecting the light emitting diode chip 40. It can be made of). The wiring portion 38 is connected to the chip die 42 to supply a current required for light emission. The configuration of the light emitting diode element is not limited to the above example, and all known light emitting diode elements can be applied as the point light source 36.

The light emitting device 10 having the above-described configuration applies a predetermined driving voltage to the first electrodes 24 and the second electrodes 26 from the outside of the vacuum container, and a direct current of a quantity of several thousand volts to the anode electrode 32. A voltage is applied and a predetermined voltage is applied to the point light sources 36 for driving.

Then, in the pixels where the voltage difference between the first electrode 24 and the second electrode 26 is greater than or equal to the threshold, an electric field is formed around the electron emission unit 28, and electrons are emitted therefrom, and the emitted electrons are attracted to the anode voltage. It emits light by colliding with a portion of the fluorescent layer 30. The emission intensity of the fluorescent layer 30 for each pixel corresponds to the electron beam emission amount of the corresponding pixel. In addition, the point light sources 36 emit light at a constant luminance on the outer surface of the second substrate 14.

In the above-described driving process, the light emitting device 10 according to the present embodiment removes the non-light emitting portion due to the mounting of the spacer 34 by installing the point light sources 36 on the outer surface of the second substrate 14. Uniform luminance can be achieved. In addition, since the diffusion plate may be omitted on the entire surface of the light emitting device 10, it is possible to prevent a decrease in luminance due to the diffusion plate.

Meanwhile, in the above-described embodiment, the first substrate 12 and the second substrate 14 may be positioned at intervals of 5 to 20 mm. The anode electrode 32 may be provided with a high voltage of about 10 kV or more, preferably about 10 to 15 kV. The light emitting device 10 according to the present exemplary embodiment may implement a maximum luminance of about 10,000 cd / m ² or more in the center of the effective region through the above-described configuration.

6 is an exploded perspective view of a display device according to an exemplary embodiment in which the above-described light emitting device is used as a light source. The display device shown in FIG. 6 is for illustrating the present invention, but the present invention is not limited thereto.

Referring to FIG. 6, the display device 100 includes a light emitting device 10 and a display panel 50 positioned in front of the light emitting device 10. A top chassis 62 and a bottom chassis 64 are positioned in front of the display panel 50 and behind the light emitting device 10, respectively.

The display panel 50 is formed of a liquid crystal display panel or another light receiving display panel. Below, the case where the display panel 50 is a liquid crystal display panel is demonstrated as an example.

The display panel 50 includes a TFT panel 52 composed of a plurality of thin film transistors (TFTs), a color filter panel 54 positioned on the TFT panel 52, and these panels 52 and 54. It includes a liquid crystal layer (not shown) injected in between. Polarizers (not shown) are attached to the upper portion of the color filter panel 54 and the lower portion of the TFT panel 52 to polarize light passing through the display panel 50.

The TFT panel 52 is a transparent glass substrate on which a matrix thin film transistor 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 56 and 58 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 54 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 thereof.

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 54. The arrangement angle of the liquid crystal injected between the TFT panel 52 and the color filter panel 54 is changed by this electric field, and the light transmittance is changed for each pixel according to the changed arrangement angle.

The printed circuit boards 56 and 58 of the display panel 50 are connected to the respective driving IC packages 561 and 581. In order to drive the display panel 50, the gate printed circuit board 56 transmits a gate driving signal, and the data printed circuit board 58 transmits a data driving signal.

The light emitting device 10 forms fewer pixels than the display panel 50 so that one pixel of the light emitting device 10 corresponds to two or more pixels of the display panel 50. Each pixel of the light emitting device 10 may emit light corresponding to the highest gray level among the pixels of the display panel 50 corresponding thereto, and the light emitting device 10 may express 2 to 8 bits of gray level for each pixel. have.

For convenience, a pixel of the display panel 50 is called a first pixel, a pixel of the light emitting device 10 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 10, a signal controller (not shown) for controlling the display panel 50 detects the highest gray level among the first pixels of the first pixel group, and according to the detected gray level, the second pixel. The method may include calculating a grayscale required for light emission, converting the grayscale to digital data, and generating a driving signal of the light emitting device 10 using the digital data. The driving signal of the light emitting device 10 includes a scan driving signal and a data driving signal.

The printed circuit board (not shown) of the light emitting device 10, that is, the scanning printed circuit board and the data printed circuit board, is connected to the respective driving IC packages 371 and 391. In order to drive the light emitting device 10, the scan printed circuit board transmits a scan drive signal, and the data printed circuit board transmits a data drive signal. One of the above-described first electrode 24 and the second electrode 26 receives a scan driving signal, and the other electrode receives a data driving signal.

The second pixel of the light emitting device 10 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 10 may form 2 to 99 pixels in a row direction and a column direction. In addition, the light emitting device 10 may provide a uniform amount of light toward the display panel 50 on the entire light emitting surface when the plurality of point light sources 36 are disposed outside the second substrate 14. Can be.

As such, the light emitting device 10 independently controls the light emission intensity of each pixel to provide light of appropriate intensity to the pixels of the display panel 50 corresponding to each pixel. Therefore, the display device 100 of the present exemplary embodiment can increase the dynamic contrast of the screen and can realize a clearer picture quality.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the range of.

The light emitting device according to the present invention can emit light with uniform luminance across the entire light emitting surface by removing the non-light emitting portion by the spacer by installing point light sources on the outer surface of the second substrate. Therefore, the diffusion plate installation can be omitted, it is possible to prevent the reduction in brightness due to the diffusion plate installation. In addition, the display device according to the present invention using the above-described light emitting device as a light source can improve the display quality by increasing the dynamic contrast ratio of the screen.

Claims (10)

A vacuum container composed of a first substrate, a second substrate, and a sealing member; An electron emission unit provided on one surface of the first substrate and emitting electrons; A light emitting unit provided on an inner surface of the second substrate facing the first substrate and emitting visible light by the electrons; A plurality of spacers disposed between the first substrate and the second substrate; And A plurality of point light sources provided on the outer surface of the second substrate corresponding to the spacer mounting position Light emitting device comprising a. The method of claim 1, The light emitting device of which the said point light sources are a light emitting diode element. The method of claim 2, Further comprising a wiring portion electrically connected to the point light sources along one direction of the second substrate, A light emitting device in which the wiring portion is formed of any one of a transparent electrode and a fine wire electrode. The method according to any one of claims 1 to 3, The electron emission unit may emit electrons electrically connected to one of the scan electrodes and the data electrodes and the scan electrodes and the data electrodes formed along the direction crossing each other while maintaining an insulating state on the first substrate. A light emitting device comprising the parts. A display panel displaying an image; And A light emitting device that provides light to the display panel Including; The light emitting device includes a vacuum container including a first substrate, a second substrate, and a sealing member, an electron emission unit provided on one surface of the first substrate to emit electrons, and an inner surface of the second substrate facing the first substrate. A light emitting unit provided and emitting visible light by electrons, a plurality of spacers provided between the first substrate and the second substrate, and a plurality of point light sources installed corresponding to the spacer mounting position on the outer surface of the second substrate Display device comprising a. The method of claim 5, And the light sources are light emitting diode elements. The method of claim 6, The light emitting device further includes a wiring unit electrically connected to the point light sources along one direction of the second substrate, The display device is formed by any one of the transparent electrode and the fine wire electrode. The method according to any one of claims 5 to 7, The electron emission unit may emit electrons electrically connected to one of the scan electrodes and the data electrodes and the scan electrodes and the data electrodes formed along the direction crossing each other while maintaining an insulating state on the first substrate. Display device including the parts. The method of claim 5, The display panel includes first pixels, And a light emitting device having a smaller number of second pixels than the first pixels, wherein the light emission intensity is independently controlled for each second pixel. The method according to claim 5 or 9, A display device wherein the display panel is a liquid crystal display panel.

Images