JP2006286908A - Light emitting diode module and color liquid crystal displaying apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting diode module for enabling radiation of lights in the equal radiation characteristic from a plurality of light emitting diodes. <P>SOLUTION: The light emitting diode module comprises light emitting diodes 10B, 10G, and 10R of at least two or more colors. The lights emitted from the light emitting diodes 10B, 10G, and 10R are respectively radiated independently. Moreover, the chips 10B, 10G, and 10R of the light emitting diodes form a light emitting diode module 20 wherein these chips are laminated almost in the vertical direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting diode module comprising light emitting diodes of a plurality of colors. The present invention also relates to a color liquid crystal display device using this light emitting diode module as a backlight light source.

Light emitting elements, including light emitting diodes (LEDs), are well known solid state devices that can generate light having a peak wavelength in a specific region of the light spectrum.
This light emitting diode is typically used as an illuminator, indicator and display.

  In recent years, gallium nitride (GaN) light-emitting diodes that can efficiently emit blue light have been developed, and their applications are greatly expanding.

  In particular, there are many products that convert blue light emitted from a gallium nitride-based light emitting diode to generate light having a longer wavelength (see, for example, Patent Document 1). These are a light-emitting element made of a gallium nitride semiconductor formed on a sapphire substrate that emits visible blue light, and Ce that absorbs blue light from the light-emitting element and can emit a complementary yellow color. By combining with the activated YAG phosphor, white light emission is obtained, and it is possible to emit light with higher color rendering than in the past.

Japanese Patent No. 3509665

However, when the above-described light emitting diode that emits white light (so-called white LED) is used as a backlight light source of a color liquid crystal display device, the emission band of the phosphor is very broad. There is a problem that the wavelength band to be cut by becomes very large.
In addition, since the red color is weak, the color gamut of the light that has passed through the liquid crystal is narrowed, resulting in a lack of color reproducibility.

  As a method for solving the above-mentioned problem, for example, three semiconductor light emitting elements that emit light of R, G, and B, which are the three primary colors of light, are arranged side by side, and these semiconductor light emitting elements are mounted in a single module. It is possible to do.

  However, with such a configuration, each of the semiconductor light emitting elements has a finite size. Therefore, even if the semiconductor light emitting elements are arranged close to each other in a plan view, the positional relationship with the lens on the top thereof is not limited. Since they are different, the radiation characteristics (radiation angle and intensity distribution, etc.) are different for each color (R, G, B).

  When a light emitting diode module having different emission characteristics for each color is used as a backlight light source of a liquid crystal display device, the colors that are supposed to be uniformly white light are separated, and a color unrelated to the display image is displayed. There was a problem of being.

  In order to solve the above-mentioned problems, the present invention provides a light emitting diode module that enables light to be emitted from light emitting diodes of a plurality of colors with the same radiation characteristics. The present invention also provides a color liquid crystal display device using the light emitting diode module as a backlight light source.

  The light emitting diode module of the present invention has light emitting diodes of at least two colors, light emitted from each light emitting diode is independently emitted, and chips of each light emitting diode are stacked in a substantially vertical direction. It is what.

  The color liquid crystal display device of the present invention comprises a transmissive color liquid crystal display panel provided with a color filter, and a backlight light source for liquid crystal display that illuminates the color liquid crystal display panel from the back side. The light emitting diode module of the present invention having a red light emitting diode, a green light emitting diode, and a blue light emitting diode (that is, light emitted from each light emitting diode is independently emitted, and the chip of each light emitting diode is substantially vertically oriented. The light emitting diode module is laminated).

  According to the configuration of the light emitting diode module of the present invention described above, the light emitting diode includes at least two colors of light emitting diodes, the light emitted from each light emitting diode is independently emitted, and the chip of each light emitting diode is substantially formed. Since the light emitting diodes are stacked in the vertical direction, the horizontal positions of the light emitting diodes are aligned, and the light emitted from the light emitting diodes can be aligned in a substantially parallel direction. Thereby, the emitted light of the light emitting diodes of two or more colors can be mixed almost uniformly.

  In addition, according to the configuration of the color liquid crystal display device of the present invention described above, the backlight source includes the light emitting diode module of the present invention having a red light emitting diode, a green light emitting diode, and a blue light emitting diode, so Uniform white light can be obtained by uniformly mixing light from the diode, green light emitting diode, and blue light emitting diode. As a result, the above-described problem of color separation can be solved, and the color corresponding to the image to be displayed can be displayed in the color liquid crystal display device.

  According to the light emitting diode module of the present invention described above, the light emitted from the light emitting diodes of two or more colors can be mixed almost uniformly, so that the light obtained by mixing can have good radiation characteristics.

  In addition, according to the color liquid crystal display device of the present invention, the color gamut can be widened by making use of the wide color gamut of the light-emitting diode, and color mixing within the backlight light source is facilitated, resulting in high display characteristics. Can be realized.

The present invention is a light emitting diode module comprising light emitting diodes of a plurality of colors (at least two colors), wherein light emitted from each light emitting diode is radiated independently, and chips of each light emitting diode are stacked in a substantially vertical direction. It is characterized by.
With this configuration, the horizontal positions of the light emitting diodes are aligned, and the light emitted from the light emitting diodes can be aligned in a substantially parallel direction. The light emitted from the diode can be mixed almost uniformly.
Therefore, the light obtained by mixing can have good radiation characteristics.

In this light-emitting diode module, each light-emitting diode chip may be arranged at the center of the base having a reflective surface made of an optical multilayer film.
In such a configuration, the light emitted from the chip of each light emitting diode is reflected by the reflecting surface of the optical multilayer film, and the reflected light is aligned in a substantially parallel direction with the same optical axis. Is possible. In this case, since the proportion of light passing through the chip of the upper layer light emitting diode can be reduced as compared with a configuration in which no reflecting surface is used, there is no attenuation when passing through the chip, and it is efficient. The emitted light can be used.

In this light-emitting diode module, the optical multilayer film on the reflection surface may be configured to reflect only light in the emission wavelength band of the light-emitting diode disposed at the center of the corresponding base.
In such a configuration, the optical multilayer film on the reflecting surface transmits the light from the chips stacked on the lower layer side and reflects the light from the light emitting diodes arranged on the corresponding base. Light and transmitted light can be emitted upward.

This light-emitting diode module has a red light-emitting diode, a green light-emitting diode, and a blue light-emitting diode. The stacking order of these light-emitting diodes is arranged in the upper layer in the order of blue light-emitting diode, green light-emitting diode, and red light-emitting diode. It can also be set as a structure.
In such a configuration, the light from the light emitting diodes arranged in the lower layer is transmitted through the chip of the light emitting diodes arranged in the upper layer, so that the light transmitted through the chip can also be used. .

As an embodiment of the present invention, a schematic configuration diagram of a light emitting diode module is shown in FIG.
The light emitting diode module 20 has three primary color (blue B, green G, and red R) light emitting diode chips 10B, 10G, and 10R provided on a base substrate 16 having a concave upper surface. Three such structures are stacked.
Lights L1, L2, and L3 emitted from the respective light emitting diode chips 10B, 10G, and 10R are independently emitted.

  The region 17 between the base substrates 16 is filled with a transparent material (resin or the like) or is hollow.

The entire base substrate 16 including the light emitting diode chips 10B, 10G, and 10R is housed in a case 18.
In addition, in FIG. 1, although the upper surface of case 18 is made into the plane, it is good also as a convex curved surface or concave curved surface of a lens shape.

  Here, the structure of one color (blue light emitting module) corresponding to the blue B light emitting diode chip 10B of the light emitting diode module 20 of FIG. 1 is shown in FIGS. 2 is a perspective view, and FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG.

As shown in FIGS. 2 and 3, the base substrate 16 has a dichroic mirror 12 formed on the front surface (upper surface) side of the base film 13, a transparent wiring 14 formed on the back surface (lower surface) side of the base film 13, and An insulating material 15 is formed so as to cover the transparent wiring 14.
The dichroic mirror 12 reflects the blue wavelength band and transmits visible light in other wavelength bands.
The transparent wiring 14 can be made of a material that is usually used for a transparent electrode or the like, for example, ITO (indium tin oxide).
As the insulating material 15, a transparent insulating material, for example, an acrylic resin is used.

The blue light emitting diode chip 10 </ b> B is provided at the center of the concave surface of the base substrate 16. Preferably, the base axis of the concave surface of the base substrate 16 is arranged so that the optical axis of the emitted light from the light emitting diode chip 10B substantially coincides.
The blue B light emitting diode chip 10 </ b> B is electrically connected to the transparent wiring 14 through the stud bump 11 that penetrates the base substrate 16 and reaches the transparent wiring 14. Thereby, a voltage is supplied to the chip 10 </ b> B through the transparent wiring 14.

The green light emitting module corresponding to the green G light emitting diode chip 10G and the red light emitting module corresponding to the red R light emitting diode chip 10R are also the same as the blue light emitting module corresponding to the blue B light emitting diode mode chip 10B. It is made up of.
However, in a green light emitting diode, the dichroic mirror has a characteristic of reflecting a green wavelength band and transmitting visible light in other wavelength bands.
In the red light emitting diode, the dichroic mirror has a characteristic of reflecting the red wavelength band and transmitting visible light in the other wavelength band, or simply a reflecting mirror instead of the dichroic mirror.

Then, the three color light emitting modules are arranged from the lower layer, the red light emitting module corresponding to the red R light emitting diode chip 10R, the green light emitting module corresponding to the green G light emitting diode chip 10G, and the blue B light emitting diode chip 10B. By stacking the blue light emitting modules corresponding to the above in order and storing them in the case 18, the light emitting diode module 20 shown in FIG. 1 can be configured.
The transparent wiring 14 of the base substrate 16 is connected to a wiring (not shown) in the case 18 by a contact 19 shown in FIG. 1, and a voltage is supplied to the light emitting diode chips 10B, 10G, and 10R through the transparent wiring 14 from the outside. Is done.

At this time, the light emitting diode chips 10R, 10G, and 10B of each color are arranged so as to be aligned substantially perpendicular to the light emitting surface.
Moreover, the curvature of the curved surface of the upper surface (dichroic mirror 12) of the three base substrates 16 is equal.
Accordingly, the light L1 emitted from the blue B light emitting diode chip 10B, the light L2 emitted from the green G light emitting diode chip 10G, and the red R light emitting diode chip 10R shown by arrows in FIG. Are emitted by the dichroic mirrors of the base substrate 16 to become substantially parallel light beams having substantially the same optical axis.

  Note that the light beams L1, L2, and L3 shown in FIG. 1 are examples of light emitted from the chips 10B, 10G, and 10R. Actually, the light beams L1, L2, and L3 are outward from the central axes of the chips 10B, 10G, and 10R. Radiated to head.

Further, it is desirable that the light emitting diode chips 10B, 10G, and 10R of each color have a radiation characteristic that mainly emits in the lateral direction rather than the upward direction of the chips 10B, 10G, and 10R.
If comprised in this way, even if it does not make the curvature of the concave surface of the base substrate 16 so large, light can be reflected upwards.

According to the configuration of the light emitting diode module 20 of the present embodiment, the three color light emitting modules are stacked so that the chips 10R, 10G, and 10B of the light emitting diodes of the respective colors are arranged in a substantially vertical direction. Color emission characteristics can be made to be almost the same.
Thereby, uniform white light emission is obtained.

  Therefore, for example, when used as a backlight light source of a liquid crystal display device, it is possible to display colors corresponding to a display image by preventing the colors from being separated, and to fully utilize the characteristics of the light emitting diode having a wide color gamut. Wide color gamut can be displayed. Further, color mixing within the backlight light source is facilitated and the color reproduction range is widened, so that high display characteristics can be realized.

  The light emitting diode module 20 of this Embodiment can be manufactured as follows, for example.

First, the dichroic mirror 12 that reflects the blue wavelength band and transmits other visible light is formed on the surface side of the base film 13.
Next, a transparent wiring 14 made of, for example, ITO (indium tin oxide) is formed on the back surface of the base film 13.
The dichroic mirror 12 and the transparent wiring 14 are preferably formed using a sputtering method.
Further, an insulating material 15 is formed so as to cover the transparent wiring 14 on the back surface side of the base film 13, and the base substrate 16 is produced.

Next, a semiconductor light emitting element chip 10 </ b> B that emits blue light is mounted on the center portion of the base substrate 16 so as to be electrically connected to the transparent wiring 14 via the stud bumps 11.
Thereafter, the dichroic mirror 12 is molded by heat treatment to form a concave shape. Thereby, a blue light emitting module is formed.

For red and green, modules of each color are formed through the same manufacturing process as blue. Since the manufacturing process is the same, detailed description is omitted.
The modules of the respective colors thus formed are stacked and stored in the case 18. At this time, the transparent wiring 14 of the base substrate and the wiring in the case 18 are connected by the contact 19.
In this way, the light emitting diode module 20 shown in FIG. 1 can be manufactured.

Using the light emitting diode module 20 of the above-described embodiment as a backlight light source, for example, a color liquid crystal display device as shown below can be configured.
FIG. 4 shows a schematic configuration diagram (disassembled perspective view) of the color liquid crystal display device.
The color liquid crystal display device 100 is a transmissive color liquid crystal display device, and includes a transmissive color liquid crystal display panel 110 and a backlight device 140 provided on the back side of the color liquid crystal display panel 110.

  Although not shown, the color liquid crystal display device 100 includes a receiving unit such as an analog tuner and a digital tuner that receives terrestrial and satellite waves, a video signal processing unit that processes video signals and audio signals received by the receiving unit, An audio signal processing unit, an audio signal output unit such as a speaker that outputs the audio signal processed by the audio signal processing unit, and the like may be provided.

  In the transmissive color liquid crystal display panel 110, two transparent substrates (TFT substrate 111 and counter electrode substrate 112) made of glass or the like are arranged to face each other, and, for example, twisted nematic (TN) liquid crystal is provided in the gap. The liquid crystal layer 113 encapsulating the liquid crystal layer 113 is provided. On the TFT substrate 111, signal lines 114 arranged in a matrix, scanning lines 115, thin film transistors 116 serving as switching elements arranged at intersections of the signal lines 114 and the scanning lines 115, and pixel electrodes 117 are formed. Has been. The thin film transistor 116 is sequentially selected by the scanning line 115 and writes the video signal supplied from the signal line 114 to the corresponding pixel electrode 117. On the other hand, a counter electrode 118 and a color filter 119 are formed on the inner surface of the counter electrode substrate 112. The color filter 119 is divided into a plurality of segments corresponding to each pixel.

The color liquid crystal display device 100 includes an active matrix in a state in which the transmissive color liquid crystal display panel 110 having such a configuration is sandwiched between two polarizing plates 131 and 132 and white light is irradiated from the back side by the backlight device 140. By driving according to the method, a desired full-color image can be displayed.
The backlight device 140 illuminates the color liquid crystal display panel 110 from the back side. As shown in FIG. 4, the backlight device 140 includes a backlight housing provided with a light source (see FIG. 5) and an optical filter (not shown) for mixing light emitted from the light source into white light. The structure includes a body 120, a diffusion plate 141, and an optical function sheet group 145 such as a diffusion sheet 142, a prism sheet 143, and a polarization conversion sheet 144 that are arranged on the diffusion plate 141.
The diffusing plate 141 makes the luminance emitted from the surface emission uniform by internally diffusing the light emitted from the backlight casing 120.
In general, the optical function sheet group has, for example, a function of decomposing incident light into orthogonal polarization components, a function of compensating for a phase difference of light waves to achieve a wide-angle viewing angle and preventing coloring, a function of diffusing incident light, and a brightness improvement And is provided to convert the light emitted from the backlight device 140 into illumination light having optical characteristics optimal for illumination of the color liquid crystal display panel 110. . Therefore, the configuration of the optical function sheet group 145 is not limited to the diffusion sheet 142, the prism sheet 143, and the polarization conversion sheet 144 described above, and various optical function sheets can be used.

FIG. 5 shows a schematic configuration diagram in the backlight housing 120. As shown in FIG. 5, the backlight housing 120 uses the light emitting diode module 20 shown in FIG. 1 as a light source.
In the light emitting diode module 20 shown in FIG. 1, for example, red light emitted from the red R light emitting diode chip 10R, green light emitted from the green G light emitting diode chip 10G, and blue B light emitting diodes. The peak wavelengths of blue light emitted from the chip 10B are about 640 nm, 530 nm, and 450 nm, respectively.
The peak wavelengths of red light and blue light may be shifted from 640 nm to the longer wavelength side and from 450 nm to the shorter wavelength side, respectively. In this way, when the peak wavelength is shifted to the long wavelength side and the short wavelength side, the color gamut can be expanded, so that the color reproduction range of the image displayed on the color liquid crystal display panel can be expanded.

As shown in FIG. 5, the light emitting diode unit 21n (n is a natural number) is formed by arranging a plurality of the light emitting diode modules 20 in a line on the substrate 22, as shown in FIG.
As shown in FIG. 5, the arrangement of the light emitting diode units 21n in the backlight housing 120 may be arranged so that the longitudinal direction of the light emitting diode units 21n is in the horizontal direction. However, the light emitting diode units 21n may be arranged so that the longitudinal direction thereof is the vertical direction, or both may be combined.
The method of arranging the light emitting diode units 21n so that the longitudinal direction is the horizontal direction or the vertical direction is the same as the way of arranging CCFLs (cold cathode tubes) used as the light source of the conventional backlight device. Therefore, the accumulated design know-how can be used, and the cost and time required for manufacturing can be shortened.
The inner wall surface 120a of the backlight housing 120 is a reflective surface that has been subjected to reflection processing in order to increase the utilization efficiency of the light emitted from the light emitting diode module 20.

  Since the color liquid crystal display device 100 uses the light emitting diode module 20 shown in FIG. 1 as the light source of the backlight device 140, uniform white light emission can be obtained by the light emitting diode module 20. Therefore, it is possible to display a color corresponding to the display image without being separated, and to display a wide color gamut by fully utilizing the characteristics of the light emitting diode having a wide color gamut. Further, color mixing within the backlight light source is facilitated and the color reproduction range is widened, so that high display characteristics can be realized.

In the light emitting diode module 20 of the above-described embodiment, each of the three primary color light emitting diodes (R, G, B) is stacked to constitute a module. However, the present invention may be applied to other configurations. it can.
The present invention is applicable as long as the light emitting diode has a plurality of emission colors, and the combination of the plurality of emission colors is not limited. For example, two colors can be selected from the above three primary colors, or other visible light can be used. A combination including light emitting diodes having emission colors in a band may be used. Further, the number of light emitting diodes for each light emitting color is not limited to one, and a plurality of light emitting diodes for some or all of the light emitting colors may be stacked.

In addition, as for the lamination | stacking order of the light emitting diode of multiple colors, it is desirable to arrange | position to the upper layer, so that the light emission wavelength is short.
This is because, when arranged in the upper layer in the order of the longer emission wavelength, the light from the light emitting diode having the shorter emission wavelength does not pass through the chip of the light emitting diode having the longer emission wavelength. . In addition, when this reduction | decrease of emitted light is a quantity which can be disregarded, a lamination | stacking order is not ask | required.
Also in the embodiment shown in FIG. 1, the stacking order of the red light emitting diode, the green light emitting diode, and the blue light emitting diode is arranged on the upper layer in the order of the shortest emission wavelength, that is, the blue light emitting diode, the green light emitting diode, and the red light emitting diode. ing.

  In addition, it is ideal that the chips of the light emitting diodes to be stacked have exactly the same size and horizontal position, but uniform light (for example, white light) is obtained by mixing light of each color with the optical axes substantially aligned. As long as it is possible, there may be a slight deviation in the size and position of the chip.

Furthermore, in the light emitting diode module 20 of the above-described embodiment, the upper surface of the base substrate 16 has a concave curved surface, and the dichroic mirror 12 is formed as a reflective surface. It is not limited to the structure in which the reflective surface is formed on the upper surface.
For example, as a configuration in which each light emitting diode chip emits more light in the upward direction than in the lateral direction, a light emitting module in which the light emitting diode chip is disposed on a flat transparent base substrate is stacked, and then passed through a reflective surface. It is also possible to emit directly without it. Also in this case, it is possible to perform uniform color mixing by aligning light emitted from each light emitting diode substantially in parallel.

  When the configuration is such that the light is reflected by the reflecting surface and emitted, the position of the optical axis of the emitted light of each light emitting diode can be substantially aligned as compared with the case where the light is emitted directly without passing through the reflecting surface. In addition, there is an advantage that the light use efficiency can be improved by reducing the ratio of the light passing through the chip of the light emitting diode stacked on the upper layer to reduce the loss due to the light passing through the chip.

  The light emitting diode module of the present invention is not limited to the light source of the backlight of the color liquid crystal display device as shown in FIGS. 4 and 5, but can be used as a light source of a wide range of devices such as other lighting devices. .

  The present invention is not limited to the above-described embodiment, and various other configurations can be taken without departing from the gist of the present invention.

It is a schematic block diagram (sectional drawing) of the light emitting diode module of one embodiment of this invention. It is a perspective view of the structure for 1 color in the light emitting diode module of FIG. It is sectional drawing in AA 'of FIG. It is a schematic block diagram (disassembled perspective view) of a color liquid crystal display device. It is a schematic block diagram of the backlight housing | casing part of FIG.

Explanation of symbols

10B Blue light emitting diode chip, 10G Green light emitting diode chip, 10R Red light emitting diode chip, 11 Stud bump, 12 Dichroic mirror, 13 Base film, 14 Transparent wiring, 15 Insulating material, 16 Base substrate, 18 Case , 20 Light emitting diode module, 100 color liquid crystal display device, 110 color liquid crystal display panel, 120 backlight casing, 140 backlight device

Claims (5)

Comprising light emitting diodes of at least two colors,
The light emitted from each light emitting diode is emitted independently,
And the chip | tip of each said light emitting diode is laminated | stacked on the substantially perpendicular direction. The light emitting diode module characterized by the above-mentioned.   2. The light emitting diode module according to claim 1, wherein the chip of each of the light emitting diodes is disposed in a central portion of a base having a reflection surface by an optical multilayer film.   The optical multilayer film of each of the reflection surfaces is configured to reflect only light in the emission wavelength band of the light-emitting diode disposed in the central portion of the corresponding base. Light emitting diode module.   It has a red light emitting diode, a green light emitting diode, and a blue light emitting diode, and the stacking order of these light emitting diodes is arranged in the order of the blue light emitting diode, the green light emitting diode, and the red light emitting diode from the upper layer. The light emitting diode module according to claim 1. A transmissive color liquid crystal display panel with a color filter;
A color liquid crystal display device comprising a backlight light source for liquid crystal display for illuminating the color liquid crystal display panel from the back side,
A light-emitting diode module comprising a red light-emitting diode, a green light-emitting diode, and a blue light-emitting diode, wherein light emitted from each light-emitting diode is radiated independently, and chips of each light-emitting diode are stacked in a substantially vertical direction A color liquid crystal display device, wherein the backlight light source is configured.

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