KR100628125B1 - lighting apparatus using LED and projection display system using it - Google Patents

Abstract

The present invention relates to a high-output surface light source by improving the structure of the LED to apply the LED as a surface light source, and relates to a miniaturized projection display device using the same. The present invention provides a substrate, a p-layer having a flat surface on the substrate and at least one or more portions formed at a predetermined height at the edge thereof, the p-layer being bonded to the positive electrode, and a light-emitting layer generating light through an electrical signal on the flat surface of the p-layer. And a transparent electrode formed on the light emitting layer at the same height as the p layer formed at the predetermined height and bonded to the negative electrode, the transparent electrode contacting the p layer and the n layer to provide a positive electrode and a negative electrode, respectively, and the transparent electrode. The present invention provides a lighting apparatus including a reflecting layer formed below and reflecting light generated from the light emitting layer, and a projection display apparatus configured to use the lighting apparatus.

Illumination device, projection display, optical system, LED, surface light source

Description

Lighting apparatus using LED and projection display system using it}

1 is a view showing the configuration of a conventional single-panel projection display device;

Figure 2a is a view showing a sequential color separation method of a general color wheel

FIG. 2B is a diagram illustrating a time configuration of a color separation signal according to the sequential color separation of FIG. 2A

3 is a view showing the structure of a typical LED

Figure 4 (a) (b) is a perspective view and a top view showing a lighting device comprising a surface light source by arranging a number of conventional LEDs

5 is a block diagram of a projection display device according to the present invention, showing a first embodiment;

6 is a view showing the configuration of a lighting device using an LED according to the present invention;

7 is a view showing a detailed configuration of the LED chip of the lighting apparatus using the LED according to the present invention

8 is a block diagram of a projection display device according to the present invention, showing a second embodiment;

9 is a view showing a time configuration diagram of a color separation signal according to the present invention;

* Explanation of symbols for main parts of the drawings

511, 512, 513: LED light source 520: synthetic prism

530: road lens 540: DOE

550: color wheel 560: illumination lens

570: TIR prism 580: DMD

590: projection lens 610: LED chip

620: LED base 710: LED substrate

720: LED p layer 730: light emitting layer

740: LED n-layer 750: transparent electrode

760: reflective layer 770: electrical signal

780: reflectors 811, 812, 813: LED surface light source

820: Synthetic Prism 830: Road Lens

840: DOE 850: Illumination Lens

860: TIR prism 870: DMD

880: projection lens

The present invention relates to an illumination device comprising three colors of a surface emitting light source and combining three colors, and a projection display device using the same to implement a projection screen.

Recently, large screen and high-definition display devices have emerged as one of the most important issues, and until now, such large-screen display devices have been developed and commercialized such as direct view liquid crystal displays, plasma displays, projections, projectors, and the like.

1 is a view illustrating a configuration of a conventional single-panel projection display device. As shown in FIG. 1, a single-panel projection display device includes a lamp 210, a focusing lens 220, a color wheel 230, and a rod lens ( 240, an illumination lens 250, a TIR prism 261, a DMD 280, a projection lens 270, and a screen 290.

A single-panel projection display device configured as described above will be described below with reference to FIG. 1.

White light emitted from the lamp 210, which is a light source, is focused by the focusing lens 220 and is incident on the color wheel 230.

In this case, the color wheel 230 rotates rapidly as shown in FIG. 2A and sequentially decomposes white light into R, G, and B lights. That is, as the color wheel 230 rotates, the white light from the lamp 210 is sequentially irradiated to three regions R, G, and B of the color wheel 230, and each of the regions R, G, and B rotates sequentially. White light transmits only the wavelength band corresponding to it.

Therefore, in the color wheel 230, R, G, and B light are sequentially output.

Subsequently, the light transmitted through the color wheel 230 is incident on the rod lens 240 so that the light distribution is uniform.

Light emitted from the rod lens 240 is incident on the TIR prism 261 by the illumination lens 250.

At this time, the TIR prism 261 has two prism blocks bonded to each other, and an air layer 262 is formed at an interface thereof. Therefore, since the light incident on the TIR prism 261 passes from the prism having a high refractive index to the air having a low refractive index at the interface of the TIR prism 261, the light is incident at a specific angle or more and is totally reflected.

As such, the light totally reflected at the interface of the TIR prism 261 is irradiated to the DMD 280.

In this case, the DMD 280 is a reflective display device in which fine mirrors are arranged to form pixels, and the light irradiated to the DMD 280 is modulated in phase according to an image signal input to the DMD panel 280 to provide image information. Will be contained.

The light containing the image information is projected on the screen 290 through the TIR prism 261 and the projection lens 270 to implement an image.

At this time, the light irradiated to the DMD 280 is sequentially irradiated with R, G, and B colors by the operation of the color wheel 230, and the image implemented by the DMD 280 is the same as the light of the color irradiated to the DMD. By implementing the color signal of the accurate color image will be realized.

That is, as shown in FIG. 2B, the color of the light passing through the color wheel 230 is divided into three for 1/60 second constituting one screen of the image signal, and is synchronized with the image color signal implemented by the DMD.

The projection display device does not use the entire light of the lamp used as the light source, but uses only the light of the wavelength required by the R, G, and B filters of the color wheel 230, so that the light utilization efficiency is small and color reproduction is limited. do.

To solve this problem, a method of using an LED instead of a lamp as a light source used in a projection display has been studied.

The LED is a device that emits light by an electrical signal and can be driven at low power, and thus is widely used in small optical parts and display devices. In particular, since the LED has a small wavelength range for emitting light, color reproduction is excellent and power consumption is small, so that the LED may be applied instead of the lamp of the projection display device.

3 is a view showing the structure of a general LED.

As shown in FIG. 3, the n-layer 120 is stacked on the substrate 110, and the light-emitting layer 130 and the p-layer 140 are sequentially stacked thereon.

In addition, the positive electrode 150 is in contact with the p-layer 140 and is connected to the (+) power source, and the negative electrode 16 is in contact with the substrate 110 and is connected to the (-) power source.

When a voltage is applied to the positive electrode and the negative electrode, electrons move by the voltage difference, causing energy change in the light emitting layer to emit light.

The light emitted from the light emitting layer 130 is emitted in all directions and the light is reflected around the reflector 170 to collect light in one direction, and the light is focused by the focusing lens 180 and output in one direction. .

By the way, in order to use the LED configured as a light source of the projection display device, a high power light source is required. In the case of the LED, the output is small, so that one LED is not sufficient to be used in the projection display device.

Therefore, in order to have a high output to be used as a light source of the projection display device, as shown in FIG. 4, it is used as one module or a plurality of LED modules are arranged and then each light is collected and used.

Figure 4 (a) (b) is a perspective view and a top view showing a lighting device in which a surface light source is arranged by a number of conventional LEDs.

As shown in Figure 4 (a) (b), the light emitted from each LED may be emitted from the end surface of the LED module to form a surface light source.

By the way, the LED module consisting of a plurality of LEDs for the high power light source becomes large in size.

Because, as shown in Figure 4 each LED has a volume of at least 1cm of the volume of each LED due to the configuration of the connection circuit wiring of the driving electrode 430 and the focusing lens 410 for applying a voltage, In addition, the distance 420 of the arrangement interval with the light emitting unit with the neighboring LED is also impossible to form at least 5mm or less, thereby increasing the volume of the LED module.

That is, the volume of the area occupied by the connection circuit wiring and the focusing lens occupies 90% of the size of all the LEDs.

Therefore, the number of LEDs that can be focused on a single area is difficult to obtain high power light in a limited area, and the gap is widened between the LED arrays, resulting in an irregular and irregular distribution of light.

In addition, there is a problem that the connection circuit wiring for applying a voltage to each LED is complicated.

Therefore, when constructing a large-area screen such as an outdoor billboard and viewing from a distance, the arrangement of the LED module is not a big problem in screen display. However, when applying a light source of a small display device or displaying a small screen at a close distance, the light distribution is performed. The problem is caused by non-uniformity.

In addition, in order to synthesize the colors of the LED surface light sources of R, G, and B colors and irradiate the display elements such as DMDs, the composite optical system becomes larger and more complicated, which causes a larger size of the projection display device. do.

As a result, the conventional LED is applied as a surface light source, which is difficult to use for a light source of a projection display device that can be miniaturized by applying a surface light source.

The present invention is to solve the above problems, an object of the present invention to improve the structure of the LED to apply the LED as a surface light source to configure a high power surface light source.

Another object of the present invention is to provide a projection display device of miniaturization using a high output surface light source using LEDs.

In order to achieve the above object, the present invention provides a substrate, a p-layer on the flat surface and at least one portion at the edge of the surface is formed at a predetermined height and bonded to the positive electrode, and an electrical signal on the flat surface of the p-layer A light emitting layer for generating light through the light emitting layer, an n layer formed at the same height as the p layer formed at the predetermined height on the light emitting layer and bonded to the negative electrode, and contacting the p layer and the n layer to provide a positive electrode and a negative electrode, respectively; The present invention provides a lighting device including a transparent electrode and a reflective layer formed under the transparent electrode to reflect light generated from the light emitting layer.

And it is preferably configured to further comprise a reflector formed to form an obtuse angle with the reflective layer to reflect the light generated in the light emitting layer to proceed toward the substrate.

In addition, it is preferable that a plurality of the LED chip is arranged in a horizontal, vertical direction at a predetermined interval using the LED base is configured in a plane structure so that the light generated from the LED chip surface emitting.

In this case, the plurality of LED chips are preferably divided during the synchronization signal constituting one screen of the image signal to sequentially emit red, green, and blue light.

According to another embodiment of the present invention, the present invention provides a lighting device configured as described above, a synthetic prism for synthesizing the light emitted from the lighting device, and focuses the light synthesized from the synthetic prism, A projection display device including an illumination system for generating light, an optical system for separating / modulating / synthesizing the light emitted from the illumination system according to an image signal, and an projection system for magnifying and projecting an image from the optical system To provide.

In this case, the illumination system is preferably composed of a plate-shaped lens including a DOE to reduce the radiation angle of the light synthesized in the synthesis prism.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments with reference to the accompanying drawings.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can be specifically realized for the above purpose.

Fig. 5 is a diagram showing the first embodiment of the construction of a projection display device according to the present invention.

As shown in FIG. 5, a synthetic prism for synthesizing a plurality of LED surface light sources 511, 512, 513 emitting R, G, and B light and LED surface light sources 511, 512, 513 of respective colors ( 520, a rod lens 530 for uniformizing the light distribution of the white light synthesized by the synthesizing prism 520, a DOE 540 for changing the angle of the light adhering to the rod lens 530, and A color wheel 550 for separating the color of the light emitted from the rod lens 530, an illumination lens 560 for collecting the light transmitted through the color wheel 550, and a TIR prism 570 for total reflection of the incident light. ), A DMD 580 for displaying an image by modulating the amount of light in accordance with an image signal, and a projection lens 590 for magnifying and projecting the image.

At this time, the LED surface light source 511, 512, 513 is a thin plate-shaped LED base 620 as shown in Figure 6 so that each LED chip 610 is arranged regularly in a horizontal, vertical direction to form a surface structure The light is uniformly distributed on the surface to emit light, and the inside of the LED base 620 is composed of a reflector 780.

The configuration of the LED surface light source is described in detail with reference to FIG. 7 as follows.

As illustrated in FIG. 7, the LED p layer 720 is disposed on the LED substrate 710, and the LED light emitting layer 730 and the LED n layer 740 are stacked thereon.

In this case, the LED substrate 710 uses a transparent material to allow light to pass through, and configures a portion of the edge of the LED p layer 720 to be equal to the height of the LED n layer 740.

Subsequently, the LED chips sequentially stacked in this manner are turned upside down and bonded to the transparent electrode 750. At this time, the LED p-layer 720 and the LED n-layer 740 are in contact with the positive electrode pattern and the negative electrode pattern of the transparent electrode 750, respectively, so that the electricity can pass through each other.

Next, a metal coating reflective layer 760 is bonded below the transparent electrode 750.

Finally, an electrical signal 770 is connected to the reflective layer 760 to generate a voltage difference between the p-layer 720 and the n-layer 740 of the LED to generate light in the LED light emitting layer 730. do.

In this way, the light emitted from the LED emitting layer 730 is emitted in all directions, the light emitted in the direction of the LED p-layer 720 passes through the transparent LED substrate 710.

On the other hand, the light emitted in the direction of the LED n-layer 740 passes through the transparent electrode 750 and is reflected by the reflective layer 760 to proceed in the opposite direction is transmitted through the LED substrate 710 is emitted.

As a result, the light emitted from the LED chip is emitted toward the LED substrate 710.

The light emitted from the LED chip is reflected by the reflector 780 and proceeds to light within a specific angle.

In this case, the reflector 780 may be used in common with the neighboring LED chip and is extended to form the LED base 620. In the LED chip, it is preferable that both the p-layer electrode and the n-layer electrode are disposed in the same direction and connected to the LED base 620 by bonding.

Accordingly, in the case of the conventional LED by removing the inter-electrode wiring and focusing lens, etc., which occupy 90% of the total volume, by configuring the LED as shown in Figure 7 according to the present invention that the size of one conventional LED was at least 1 cm, The size of the LED can be reduced to about 1/5 the size of 200㎛.

In this case, the output and the exit angle of the emitted LED light can be adjusted according to the shape of the reflector 780 and the LED base 620.

As such, when LED chips are arranged to form a surface light source, the number of LED chips that can be integrated in a single area is much higher than that of conventional LED modules, so that high output light can be obtained and the spacing between the LEDs is small, resulting in uniformly distributed light emission. You will get

The operation of the projection display device using the LED surface light source according to the present invention configured as described above will be described in detail with reference to the accompanying drawings.

As shown in FIG. 5, the R, G, and B LED surface light sources 511, 512, and 513 emit light of each color. At this time, the light emitted from each of the LED surface light sources 511, 512, 513 is synthesized as white light by the synthesis prism 520 and proceeds in one direction.

In this case, the synthetic prism 520 serves to change the path of light, and the dichroic coating surface for reflecting blue light and transmitting green light and red light with blue reflection, green and red transmission coating, and red reflection, green and The dichroic coating surface, which reflects red light and transmits green and blue light, is formed in an X shape at a 45 degree angle.

Accordingly, the respective colors of light emitted from the LED surface light sources 511, 512, and 513 are incident to the synthesis prism 520 perpendicularly to each other and synthesized in one direction.

That is, the R light is incident on the composite prism 520, reflected at the 45 degree reflective surface, and proceeds to the exit portion of the composite prism 520. The G light is incident on the synthetic prism 520 and passes through the 45-degree reflective surface as it is and proceeds to the emission unit. Finally, the B light is incident on the composite prism 520, reflected at the 45 degree reflective surface, and proceeds to the exit portion of the composite prism 520.

An example of such a synthetic prism 520 is an X-cube prism.

As such, the light emitted from the LED surface light sources 511, 512, and 513 and synthesized by the synthesis prism 520 is incident on the rod lens 530.

At this time, a diffraction lens (DOE) 540 is bonded to an incident part of the rod lens 530 so that light transmitted through the DOE 540 is incident on the rod lens 530 at a specific angle. do. The DOE 540 is a plate-shaped lens, which serves as a general focusing lens, but reduces the focusing lens to make it smaller in size.

That is, since the light emitted from the LED surface light sources 511, 512, 513 is emitted at a specific angle of radiation, the light cross-sectional area becomes larger as it moves away from the light source. In order to accommodate all the light having such a large cross-sectional area, a large rod lens 530 is required, which causes the size of the entire system to be large.

Therefore, a focusing lens is used to reduce the radiation angle of the light. When the focusing lens is used in this way, the space and the distance where the focusing lens is located are additionally required, which also causes a large overall size of the system. .

Therefore, when the diffractive lens (DOE) 840 is applied as in the present invention, while reducing the radiation angle of the light so as to have the same effect as the conventional focusing lens, the space and the distance where the focusing lens is located are not required, so that the rod having a smaller size The lens 830 can be used, and the system according to the entire projection display can be made smaller.

As such, the light incident through the DOE 840 and incident on the rod lens 830 at a specific angle becomes uniform in the light distribution of the light emitted by the irregular reflection in the rod lens 830.

The light emitted from the rod lens 830 is sequentially divided into R, G, and B light by the color wheel 550. Light of each separated color is focused by the illumination lens 560 and is incident on the TIR prism 570.

The light passing through the TIR prism 570 is then totally reflected at the interface of the TIR prism 570 because the light passes through the medium having the high refractive index to the air having the small refractive index. The light totally reflected by the TIR prism 570 is irradiated to the DMD 580.

Next, the DMD 580 displays an image by modulating the amount of light reflected by the image signal. In this case, when the R, G, and B lights sequentially passing through the color wheel 550 are sequentially illuminated on the DMD 580, the DMD 580 displays the same image color signal as the corresponding color to implement an accurate color image. do.

The image implemented in the DMD 580 passes through the TIR prism 570 and is enlarged and projected by the projection lens 590 to implement a screen on a screen (not shown).

8 is a diagram illustrating a second embodiment of the construction of a projection display device according to the present invention. Referring to FIG. 8, the contents according to the second embodiment will be described in detail as follows.

At this time, the basic configuration of this second embodiment is the same as that of the first embodiment described above. However, in the second embodiment, unlike the first embodiment described above, color separation is performed by sequentially turning on / off the LED surface light sources 511, 512, and 513 by replacing the color wheel 550. To configure the projection display device.

That is, as shown in FIG. 8, the color wheel 550 in the first embodiment replaces the color light sources 811, 812, and 813 by sequentially turning on / off the projection display device. Consists of.

In this case, the R, G, and B LED surface light sources 811, 812, and 813 are not always on, but are sequentially turned on / off in accordance with an image signal and irradiated to the DMD 870.

That is, only the R LED is turned on to the R color signal of the DMD 870 and the G and B LEDs are turned off, and only the G LED is turned on to the G color signal of the DMD and the R and B LEDs are turned off.

This sequential color signal is shown in FIG.

That is, as shown in FIG. 9, each of the R, G, and B LED surface light sources 811, 812, and 813 is sequentially divided into three parts for 1/60 second, which is a synchronization signal constituting one screen of an image signal, and sequentially emits light. This is the same in synchronization with the image color signal implemented in the DMD (870).

The present invention is not limited to the above-described embodiments, and can be modified by those skilled in the art as can be seen from the appended claims, and such modifications are within the scope of the present invention.

The effects of the illumination device using the LED and the projection display device using the same according to the present invention described above are as follows.

First, high output, high integration LED surface light source can be realized.

Second, the system can be miniaturized by applying as a light source of the display element of the projection display device and simply configuring the optical system.

Claims (9)

Substrate, A p layer formed on the substrate and having a flat surface and at least one portion formed at a predetermined height at an edge thereof to be bonded to the positive electrode; A light emitting layer for generating light through an electrical signal on a flat surface of the p layer; An n layer formed on the light emitting layer at the same height as the p layer formed at the predetermined height and bonded to a negative electrode; A transparent electrode in contact with the p layer and the n layer to provide a positive electrode and a negative electrode, respectively; And a reflective layer formed under the transparent electrode to reflect light generated from the light emitting layer. The method of claim 1, And a reflector formed to form an obtuse angle with the reflective layer to reflect the light generated from the light emitting layer to travel toward the substrate. The method of claim 1, A plurality of LED chips configured as described in claim 1, And arranging the plurality of LED chips at predetermined intervals in a horizontal and vertical direction to form a surface structure such that light generated from the LED chips is surface-emitted. The method of claim 3, wherein Lighting device further comprises a reflector reflecting the light generated from the LED chip to proceed in one direction between the LED chip and the LED base. The method of claim 3, wherein The LED chip is an illumination device, characterized in that consisting of a size of less than 200㎛. The method of claim 3, wherein The plurality of LED chips are divided during the synchronization signal constituting one screen of the image signal, characterized in that for sequentially emitting red, green, blue light. The lighting device is configured as described in claim 1 or 3, A synthetic prism for synthesizing light emitted from the lighting device; An illumination system that focuses the light synthesized in the synthesis prism and generates light with a constant polarization; An optical system for displaying an image by modulating and synthesizing the light emitted from the illumination system according to an image signal; And a projection lens system for magnifying and projecting an image from the optical system. The method of claim 7, wherein And the illumination system comprises a diffractive lens (DOE) configured to have a plate-shaped lens to reduce the radiation angle of the light synthesized by the synthesizing prism. The method of claim 7, wherein And the optical system comprises a color wheel that sequentially divides the light emitted from the illumination system into R, G, and B lights.

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