JP2007184493A - Light source device and display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source of good distribution in chromaticity and brightness as well as color reproductivity, by mixing light emitted from light emitting elements of two or more kinds of emission colors for emitting light of desired color with uniform distribution. <P>SOLUTION: In a light source device 10, light emitting elements 12R, 12G, and 12B of emission color of at least two kinds constitute one light emitting element group 20. In each of the light emitting element groups 20, the outgoing surfaces of the light emitting elements 12R, 12G, and 12B constituting the light emitting element group 20 are tilted to face inside. A reflection material 14 having an opening on the upper part is provided to cover the entirety of the light emitting elements 12R, 12G, and 12B. A diffusion sheet 15 of diffusion material is provided above the light emitting element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light source device including a light emitting element such as a light emitting diode as a light source, and in particular, diffuses light emission of R, G, B color light emitting diodes uniformly to obtain a desired color (white or other color). It is suitable for use in an illumination light source device that obtains a light source. The present invention also relates to a display device including a light source device that illuminates the display unit from the back side.

2. Description of the Related Art Conventionally, as a white LED light source that uses a light emitting diode (LED) to produce white light, the following two types of configurations have been proposed.
In the first configuration, a red light emitting diode, a green light emitting diode, and a blue light emitting diode are combined and mixed to obtain white light.
The second configuration is a configuration in which pseudo-white light is emitted by applying a yellow phosphor to a blue light emitting diode and exciting the phosphor.

In recent years, as the output of light emitting diodes has increased, the application of this white LED light source has expanded.
In particular, application to lighting for which high brightness is required, projector light sources, and backlights for large liquid crystal displays is considered. In these applications, from the features of light-emitting diodes such as low environmental impact due to mercury-free, good color reproducibility, good responsiveness, brightness variability, long life, etc. A white LED light source is expected as a white light source to replace conventional fluorescent tubes (hot cathode tubes and cold cathode tubes).

  When applying white LED light sources to the backlights for illumination, projector light sources, and large liquid crystal displays described above, light emission that is a point light source is currently used to achieve the required luminance and to provide a surface light source. It is necessary to use a large number of diodes.

As the structure of a backlight using a light emitting diode, two types of the edge light type and the direct type are typical.
In the edge light system, a light emitting diode is caused to emit light from a direction orthogonal to the illumination direction to an end face of a light guide plate provided on the lower surface of a diffusion plate, thereby forming a surface light source.
In the direct method, light is emitted in a vertical direction on the diffusion plate from light emitting diodes arranged in a matrix immediately below the diffusion plate.

By the way, when the white LED light source having the first configuration described above is applied to a direct-type backlight, the light from each light-emitting diode is evenly distributed in the plane within a limited backlight thickness range. Therefore, a configuration is adopted in which an optical member that diffuses light emitted from each light emitting diode light source in the lateral direction is disposed on each light emitting diode.
As this optical member, generally, a configuration using a lens or a substantially conical reflecting surface is known (see, for example, Patent Document 1 and Patent Document 2).

Japanese Utility Model Publication No. 7-3154 JP 2004-140327 A

  In the above-described white LED light source having the first configuration, an appropriate optical path length is required in order to uniformly disperse the light from each light emitting diode in the plane and mix the colors. For this reason, if the light source is configured by only the light emitting diode without providing an optical member for diffusing the light emitted from each light emitting diode light source in the lateral direction, it is necessary to ensure a certain thickness. Since it is necessary to increase the thickness, it is difficult to reduce the thickness and size of the backlight device and the display device using the backlight device.

On the other hand, as shown in Patent Document 1 and Patent Document 2, in the configuration in which optical members such as diffusion and reflection are arranged on each light emitting diode, the optical path length can be secured by using the optical members. Therefore, the backlight device and the display device can be reduced in thickness and size.
However, since an optical member is provided for each light emitting diode, it is necessary to use a large number of optical members, which increases the number of parts, materials, and assembly costs.

The white LED light source having the second configuration described above has poor color reproducibility because pseudo-white color is formed by radiating green wavelength light or red wavelength light with a phosphor.
Further, when the phosphor is deteriorated, the chromaticity is changed.

  Accordingly, there is a demand for an LED light source having a configuration in which the backlight device and the display device can be thinned and miniaturized and the color reproducibility is good.

  In order to solve the above-described problems, the present invention provides a light source device with good color reproducibility and a display device including the light source device.

In the light source device of the present invention, one light emitting element group is composed of at least two types of light emitting elements, and in each light emitting element group, the emission surface of each light emitting element constituting the light emitting element group faces inward. The light emitting element is inclined to cover the entire light emitting element constituting the light emitting element group, and a reflecting material having an opening above is provided, and a diffusion sheet made of a diffusion material is provided above the light emitting element. .
The display device of the present invention includes a display unit that displays an image and a light source device that illuminates the display unit from the back side, and this light source device is the configuration of the light source device of the present invention.

According to the configuration of the light source device of the present invention described above, in each light emitting element group, the emission surface of each light emitting element constituting the light emitting element group is inclined so as to face inward, so that The light can be collected inside and mixed.
In addition, by covering the entire light emitting element constituting the light emitting element group and providing a reflecting material having an opening above, the light emitted from each light emitting element constituting the light emitting element group is reflected by the reflecting material. be able to. The light reaching the opening is emitted from the light emitting element group. Light that hits a portion of the reflective material other than the opening is reflected and can be radiated out of the opening by changing the direction during repeated reflection. In this way, the light emitted from each light emitting element can be collected, and the collected light can be emitted to the outside of the light emitting element group through the opening of the reflecting material.
Further, in each light emitting element group, a diffusion sheet made of a diffusion material is provided above the light emitting elements, so that the light distribution can be uniformly mixed by the diffusion sheet to obtain light of a desired color. . The light reflected by the reflecting material has various directions and the amount of light varies depending on the direction. Therefore, by diffusing with the diffusion sheet, it is possible to obtain light of a desired color having a uniform distribution while suppressing variations in the amount of light depending on the direction of light.
Thereby, in each light emitting element group, each luminescent color can be mixed easily and it becomes possible to light-emit desired color (for example, white and other colors).

  According to the configuration of the display device of the present invention, the light source device that illuminates the display unit from the back side is the configuration of the light source device of the present invention, so that light of a desired color having a uniform distribution from the light source device. Therefore, the distribution of chromaticity and luminance of the image displayed on the display unit is good.

  According to the light source device of the present invention described above, it is possible to emit light of a desired color having a uniform distribution by mixing light emitted from light emitting elements of two or more types of light emission colors. A light source with good degree and luminance distribution and good color reproducibility can be realized.

For example, when it is configured so that white light can be obtained by color mixing, a good white light source can be realized.
For example, when it is configured so that colored light can be obtained by color mixing, a wide range of colors can be created and the effect of space can be improved.

  Further, it is not necessary to use a special optical member such as a lens, and it is not necessary to provide an optical member for each light emitting element, so that it is possible to reduce the number of parts and the part cost.

  Further, according to the display device of the present invention, since the chromaticity and luminance distribution of the image displayed on the display unit becomes a good distribution, the image to be displayed can be displayed with a good image quality.

  Furthermore, according to the present invention, it is possible to perform color mixing in a short distance and a small space, so that the light source device and the display device can be reduced in size and thickness.

As an embodiment of the present invention, a schematic configuration diagram of a light source device is shown in FIG.
The light source device 10 includes light emitting diodes (LEDs) 12R, 12G, and 12B of three colors (red R, green G, and blue B) provided on a substrate 11, and these are fixed to a fixing material 13, It is configured.

  In the light source device 10 of the present embodiment, as shown in FIGS. 2A and 2B, three color (red R, green G, blue B) light emitting diodes (LEDs) 12R, 12G, One light emitting diode unit 20 is configured by arranging 12B.

  Regarding the red light emitting diode 12R and the blue light emitting diode 12B, the fixing material 13 that fixes the respective substrates 11 has an inclined surface with an inclination angle θ = 45 ° with respect to the bottom surface. The exit surfaces of 12R and 12B are inclined surfaces with an inclination angle θ (45 °) with respect to the bottom surface.

The space above the light emitting diodes 12R, 12G, and 12B is surrounded by the reflective material 14 that is disposed perpendicular to the bottom surface of the light source device 10.
In addition, a diffusion sheet 15 made of a thin diffusion material is provided in the space surrounded by the reflecting material 14 so that the cross section is X-shaped.
Further, a diffusion plate 16 made of a diffusion material is provided in the opening above the space.

  For example, an aluminum plate can be used as the fixing member 13 for fixing the substrate 11.

It is desirable that the reflective material 14 has a reflectance of 90% or more with respect to light having a wavelength of 400 nm to 800 nm.
As materials having such a high reflectance, various materials are conceivable. However, when a metal is used, the weight increases. For example, a material such as PET in which bubbles are introduced, a resin having a reflective coating, etc. Is used.

As the diffusion sheet 15, a sheet using a general diffusion material having a property of transmitting light emitted from each of the light emitting diodes 12R, 12G, and 12B can be used.
For the diffusion plate 16, a general diffusion material having a property of transmitting light emitted from each of the light emitting diodes 12R, 12G, and 12B can be used. For example, a diffusing material similar to the diffusing plate (the diffusing plate 141 in FIG. 18) used for the backlight light source of the liquid crystal display device can be used.

The light emitted from the light emitting diodes 12R, 12G, and 12B strikes the diffusion sheet 15 and is diffused, so that the light of each color is mixed and emitted in various directions.
Further, the light that hits the reflecting material 14 on the side surface of the light source device 10 is reflected by the reflecting material 14 and travels obliquely upward.

Further, the light hits the diffusion plate 16 on the upper surface and is diffused, so that the light distribution can be mixed uniformly to obtain light of a desired color (for example, white light).
The light reflected by the reflecting material 14 has various directions, and the amount of light varies depending on the direction. By diffusing by the diffusion sheet 15 and the diffusion plate 16, variation in the amount of light due to the direction of the light is suppressed. It is possible to obtain light of a desired color having a uniform distribution, for example, uniform white light.

  As described above, in the light source device 10 of the present embodiment, the light emitting diode unit 20 is provided with the reflecting material 14, the diffusion sheet 15, and the diffusion plate 16, thereby providing the three light emitting diodes 12R, 12G, and 12B. The light emitted from each of these can be mixed to obtain light having a uniform distribution.

The light emitted from the light source device 10 is not limited to white light and can emit light of a desired color.
White light can be emitted by setting the ratio of the emission intensities of the three color light emitting diodes 12R, 12G, and 12B to a specific ratio.
In addition, by changing the light emission intensity of each of the three light emitting diodes 12R, 12G, and 12B, it is possible to change the chromaticity of the light emitted from the light source device 10 to obtain various colors.

According to the configuration of the light source device 10 of the present embodiment described above, the reflection surrounding the upper side surface with respect to the light emitting diode unit 20 composed of the three color light emitting diodes 12R, 12G, and 12B formed on the substrate 11, respectively. By providing the material 14, the upper X-shaped diffusion sheet 15 and the upper diffusion plate 16, the light emitted from each of the three color light emitting diodes 12R, 12G, and 12B is mixed and distributed uniformly. It can be set as the light which has.
As a result, the light source device 10 with good color reproducibility can be realized, and even when the thickness of the light source device 10 is reduced, a good chromaticity distribution can be obtained. It becomes possible to become.

And in the optical apparatus 10 of this Embodiment, it is not necessary to use special optical members, such as a lens, and it is not necessary to provide an optical member for every light emitting diode 12R, 12G, 12B. This eliminates the need to use special and expensive light emitting diodes 12R, 12G, and 12B.
Further, when an optical member such as a lens is provided for each of the light emitting diodes 12R, 12G, and 12B, it is necessary to package the light emitting diodes 12R, 12G, and 12B in order to support the optical member. Becomes unnecessary, it becomes possible to mount each light emitting diode 12R, 12G, and 12B by a bare chip.
Therefore, it is possible to reduce the number of parts and the part cost.

Furthermore, in the light source device 10 according to the present embodiment, the fixing material 13 that fixes the substrate 11 in the two light emitting diodes 12R and 12B arranged on the outer side among the three color light emitting diodes 12R, 12G, and 12B. The inclined surface is inclined at an inclination angle θ = 45 ° with respect to the bottom surface (of the light source device 10). It has become.
As a result, the light emitted from the light emitting diodes 12R, 12G, and 12B of the three colors is easily collected at the central portion of the light source device 10 and can be easily mixed with the light having a uniform distribution.

The light source device 10 of the present embodiment can be used for illumination, projector light sources, backlight devices for color liquid crystal display devices, and the like.
And since the light source device 10 of this Embodiment becomes a light source with favorable color reproducibility, it is suitable for such a use.

Next, as another embodiment of the present invention, schematic configuration diagrams of a light source device are shown in FIGS.
In the light source device of the present embodiment, as shown in the plan view of FIG. 3, four light emitting diode units 20 shown in FIGS. 2A and 2B are used, and these four light emitting diode units 20 are shared. Are arranged in parallel on the substrate 11 which is formed to be elongated.

  Furthermore, FIG. 4 shows a cross-sectional view of a portion of the light emitting diode unit 20 in the light source device of the present embodiment. As shown in FIG. 4, an array unit 30 is configured by providing a reflector 14 surrounding the side surface and a diffusion sheet 15 having an X-shaped cross section above the substrate 11 of the light emitting diode unit 20. The array unit 30 has 3 × 4 = 12 light emitting diodes 12 (12R, 12G, 12B).

In the light source device of this embodiment, the inclination of the reflecting material 14 and the diffusion sheet 15 and the length of the diffusion sheet 15 are different from those of the light source device 10 of FIG. Further, the diffusion plate 16 of FIG. 1 is not provided.
The reflector 14 is not perpendicular to the bottom surface of the light source device but is inclined with respect to the bottom surface so that the upper side is opened. The inclination angle of the reflecting material 14 is larger than the inclination angle θ of the emission surface of the outer light emitting diodes 12R and 12B.

A side view of the array unit 30 is shown in FIG.
As shown in FIG. 5, the fixing member 13 of the substrate 11 is provided not in the portion of the light emitting diode unit 20 but in the portion between the light emitting diode units 20.

FIG. 6 shows a cross-sectional view of a portion between the light emitting diode units 20 of the array unit 30.
As shown in FIG. 6, a reflective material 18 is pasted on an adhesive material (double-sided tape or the like) 17 on the three substrates 11 between the light emitting diode units 20.
With this reflecting material 18, the light directed toward the substrate 11 can be reflected upward.

FIG. 7 shows another side view of the array unit 30 (side view of the left and right sides in FIG. 5).
As shown in FIG. 7, the reflection material 14 is attached to the entire side surface so as to extend to the bottom surface, thereby preventing light from leaking inside.

According to the configuration of the array unit 30 of the present embodiment, as in the light source device 10 of the previous embodiment, a light-emitting diode unit composed of three-color light-emitting diodes 12R, 12G, and 12B formed on the substrate 11, respectively. 20 is provided with a reflector 14 surrounding the upper side surface and an upper X-shaped diffusion sheet 15 to mix the light emitted from each of the three color light emitting diodes 12R, 12G, and 12B. , Light having a uniform distribution can be obtained.
As a result, a light source device (array unit 30) with good color reproducibility can be realized, and a good chromaticity distribution can be obtained even if the thickness of the light source device is reduced, and the light source device is made thinner.・ It becomes possible to reduce the size. Further, it is not necessary to use a special optical member such as a lens, and it is not necessary to provide an optical member for each of the light emitting diodes 12R, 12G, and 12B. Therefore, it is necessary to use special and expensive light emitting diodes 12R, 12G, and 12B. The light emitting diodes 12R, 12G, and 12B can be mounted with bare chips.
Therefore, it is possible to reduce the number of parts and the part cost.

  In addition, according to the configuration of the array unit 30 of the present embodiment, as in the light source device 10 of the previous embodiment, of the three colors of light emitting diodes 12R, 12G, and 12B, two light emitting elements arranged on the outside are used. In the diodes 12R and 12B, the emission surface is an inclined surface with an inclination angle θ (45 °) with respect to the bottom surface, so that the emitted light from the three-color light emitting diodes 12R, 12G, and 12B Are easily collected and mixed with light of uniform distribution.

Furthermore, according to the configuration of the array unit 30 of the present embodiment, the reflection material 18 is provided on the substrate 11 in the portion between the light emitting diode units 20, thereby providing the reflection provided on the bottom surface side of the array unit 30. Since the material 18 can increase the efficiency of reflection on the bottom surface side, the utilization efficiency of light emitted from the light emitting diodes 12R, 12G, and 12B can be improved.
Thereby, since light can be efficiently emitted out of the array unit 30, the brightness of the emitted light can be sufficiently ensured.
In addition, since the luminance of the emitted light can be sufficiently secured, it is possible to obtain the luminance equivalent to that of the conventional configuration with less energy.
Therefore, it is possible to achieve energy saving and long life such as reduction of power consumption of the light source device (array unit 30).
Further, for example, by reducing the number of light emitting diodes 12R, 12G, and 12B in the array unit 30, the area and volume occupied by the chips of the light emitting diodes 12R, 12G, and 12B can be reduced to save space, and the component cost can be reduced. Can also be reduced.

The array unit 30 of the present embodiment can be used as a backlight source of a liquid crystal display device.
For example, the array unit 30 having the configuration shown in FIGS. 3 to 7 is arranged in a total of 18 pieces, 3 in the vertical direction and 6 in the horizontal direction, as shown in the plan view in FIG. The backlight light source device 40 can be configured.
In the figure, reference numerals 31 and 32 denote reflecting plates, and 33 denotes a housing.

Further, a longitudinal sectional view and a lateral sectional view of the backlight light source device 40 are shown in FIGS. 9 and 10, respectively.
As shown in FIGS. 9 and 10, the backlight source 40 is configured by attaching a diffusion plate 34 to the upper opening of the housing 33.

Then, by changing the number of array units 30 arranged, it is possible to correspond to screen sizes such as 32 inches, 40 inches, and 46 inches.
Table 1 shows the number of array units 30 arranged in each screen size. Table 1 also shows the number of light emitting diodes (LEDs) used.

  Since the array unit 30 is configured by arranging the light emitting diodes, it can be applied to various screen sizes as shown in Table 1 by changing the number of the array units 30 to be used. It is possible to simplify the design of a device such as a liquid crystal display device using a light source as a light source.

The number of light emitting diodes is not limited to the number shown in Table 1, but can be arbitrarily set according to the target light emission luminance.
Then, the number of light emitting diodes in the array unit may be arbitrarily set (not limited to 12 in the above-described embodiment) according to the target light emission luminance.

  As shown in FIGS. 8 to 10, when the array units 30 are added vertically and horizontally to form a light source device such as a backlight device, the side surfaces are arranged in order to make the joints between the array units 30 inconspicuous. The thickness of the reflective material 14 is desirably 0.8 mm or less.

  Here, the difference in the luminance distribution due to the difference in the configuration of the light source device (the presence or absence of the diffusion sheet and the inclination angle of the emission surface of the light emitting diode) was measured.

  11A to 11C are cross-sectional views of the light emitting diode unit portion of each configuration of the light source device used for measuring the luminance distribution.

First, in the configuration shown in FIG. 11A, the three color light emitting diodes 12R, 12G, and 12B are arranged in parallel to the bottom surface, and an array unit is configured without using a diffusion sheet.
The reflector 14 on the side surface of the array unit includes a lower portion 14A perpendicular to the bottom surface, a central portion 14B inclined with respect to the bottom surface so as to spread upward, and an upper portion 14C perpendicular to the bottom surface.
A diffusion plate 16 is provided on the upper surface of the array unit.
Further, similarly to the array unit 30 shown in FIG. 3, four light emitting diode units 20 composed of three color light emitting diodes 12R, 12G, and 12B are arranged to constitute an array unit.

The dimensions of each part of the configuration shown in FIG. 11A were as follows.
Chip size of light emitting diodes 12R, 12G, 12B: vertical and horizontal 9mm, height 4.5mm
The length of the substrate 11: 172 mm
Distance between centers of each light emitting diode unit 20: 43.5 mm
Thickness of diffusing material 16: 2.0 mm
Height of the lower part 14A of the reflector 14: 8.4mm
Height of the central part 14B of the reflector 14: 23.6 mm
Height of upper part 14C of reflector 14: 15.0mm
The width of the bottom surface of the array unit: 29.5 mm
Width of upper surface of array unit: 45.0mm
Array unit length: 174mm
Fixing member 13 thickness: 1.0 mm
In addition, the reflective material 14 used the comparatively thick reflective material for the lower part 14A and the upper part 14C, and used the comparatively thin reflective material for the center part 14B. Since the thicknesses of these reflecting materials 14A, 14B, and 14C do not directly affect the luminance distribution, description thereof is omitted.

Next, in the configuration shown in FIG. 11B, an array unit is configured by disposing a diffusion sheet 15 having an X-shaped cross section above the three-color light emitting diodes 12R, 12G, and 12B.
Other configurations are the same as those shown in FIG. 11A.

The dimensions of the diffusion sheet 15 configured as shown in FIG. 11B were as follows.
Thickness of diffusion sheet 15: 0.24 mm
Width of diffusion sheet 15: 44.1 mm (lower part 17.5 mm, upper part 26.6 mm from intersection)
Height of diffusion sheet 15: 23.6 mm (lower part 9.3 mm, upper part 14.3 mm from intersection)

Next, in the configuration shown in FIG. 11C, the fixing material 13 that fixes the substrate 11 is inclined with respect to the bottom surface at an inclination angle θ = 45 °, so that the outer side of the three-color light emitting diodes 12R, 12G, and 12B. The emission surfaces of the light emitting diodes 12R and 12B are inclined with respect to the bottom surface. Further, the reflecting material 14 does not have a lower portion 14A, and a central portion 14B of the reflecting material is provided directly on the substrate 11.
Other configurations are the same as those shown in FIG. 11B.

The dimensions of each part of the configuration shown in FIG. 11C were as follows.
The width of the substrate 11: 12 mm
Fixing member 13 thickness: 1.0 mm

The luminance distribution was measured for the configuration of these three array units.
As shown by circles in the plan view of FIG. 12, the measurement points are the rows 1 to 9 on the upper surface of the array unit, that is, the upper surface of the diffusion plate 16 (height from the light emitting diode emission surface = 44.5 mm). The total number of rows A to E was 45. Column 5 and row C are respectively on the center line in the length direction and the center line in the width direction of the array unit. In FIG. 12, the arrangement of the light emitting diodes 12R, 12G, and 12B in the configuration shown in FIG. 11C is shown overlapping the measurement points.
The interval between the measurement points was 22.0 mm between column 4, column 5 and column 6, 20.0 mm between other columns, and 8.7 mm between each row.

  Then, the output of each of the 12 light emitting diodes is adjusted so that the white balance is matched with the center line in the width direction of the array unit (the position of the measurement point in row C), and the brightness distribution is adjusted in this manner. Was measured.

In the array unit having the configuration shown in FIG. 11A, the red luminance distribution is shown in FIG. 13A, the green luminance distribution is shown in FIG. 13B, and the blue luminance distribution is shown in FIG. 13C. In the luminance distribution of each figure, the luminance (maximum value) of the center line (measurement point in row C) in the width direction of the array unit is set to 1.00 based on the measurement value of luminance at the measurement point. Contour lines are drawn in increments of 02, and so on.
Further, the ratio of the red luminance value to the blue luminance value was calculated, and this calculated value was normalized so that the luminance value ratio at the center line (position of row C) in the width direction of the array unit was 1. . The result thus obtained is shown in FIG. 13D. In FIG. 13D, a value greater than 1 indicates that the red luminance is higher than the blue luminance, and a value smaller than 1 indicates that the blue luminance is higher than the red luminance. That is, if the value in this figure is close to 1 and the luminance distribution of green is uniform, the plane white light with good uniformity is approached.

13A to 13C, the positions of the red and blue luminance peaks are divided into upper and lower parts with respect to the position of the green luminance peak. Further, in FIG. 13D, the red luminance is high on the upper side (row A side) and the blue luminance is high on the lower side (row E side).
Therefore, it can be seen that the configuration shown in FIG. 11A cannot obtain planar white light with good uniformity.

  Next, in the array unit having the configuration shown in FIG. 11B, the red luminance distribution is shown in FIG. 14A, the green luminance distribution is shown in FIG. 14B, and the blue luminance distribution is shown in FIG. 14C. FIG. 14D shows the result of normalizing the calculated value of the ratio of the red luminance value to the blue luminance value so that the ratio of the luminance value at the center line in the width direction of the array unit is 1.

14A to 14C, it can be seen that the positions of the red and blue luminance peaks approach the position of the green luminance peak. It can also be seen that the luminance distributions of the three colors are similar.
On the other hand, FIG. 14D shows that red and blue are still separated in the width direction of the array unit and have a slight color distribution.

  Next, in the array unit having the configuration shown in FIG. 11C, the red luminance distribution is shown in FIG. 15A, the green luminance distribution is shown in FIG. 15B, and the blue luminance distribution is shown in FIG. 15C. FIG. 15D shows the result of normalizing the calculated value of the ratio of the red luminance value to the blue luminance value so that the ratio of the luminance value at the center line in the width direction of the array unit is 1.

15A to 15C, it can be seen that the luminance peaks of the three colors are near the center line, and the luminance distributions of the three colors are substantially matched.
15D, the maximum value is 1.03 and the minimum value is 0.97, which is considerably close to 1.
Thereby, it turns out that plane white light with favorable color uniformity is obtained.

  That is, the diffusion sheet 15 having an X-shaped cross section is provided above the light emitting diodes 12R, 12G, and 12B, and the emission surfaces of the outer light emitting diodes 12R and 12B are inclined at an inclination angle θ = 45 ° with respect to the bottom surface. By configuring the array unit, planar white light with good color uniformity can be obtained.

In each of the above-described embodiments, the emission surfaces of the outer light emitting diodes 12R and 12B are inclined with respect to the bottom surface at an inclination angle θ = 45 °. However, the luminance distributions of the three colors (R, G, B) are the same. By doing so, plane white light with good color uniformity can be obtained, and therefore, the inclination angle of the emission surface of the light emitting diode does not necessarily have to be 45 degrees.
Further, the shape of the diffusion sheet 15 disposed in the space surrounded by the reflective material 14 is not limited to the X-shaped cross section shown in each of the above embodiments.

An embodiment in which these configurations are modified will be described below.
As still another embodiment of the present invention, a schematic configuration diagram of a light source device is shown in FIG. FIG. 16 shows a cross-sectional view of the light emitting diode unit portion of the light source device (array unit), similarly to FIGS. 11A to 11C.

In the present embodiment, as shown in FIG. 16, the inclination angle α of the outer light emitting diodes 12R and 12B is set to 30 °, and the diffusion sheet 15 is provided in parallel to the bottom surface.
Other configurations are the same as those of the array unit having the configuration shown in FIG. 11C.
Even if the array unit is configured in this way, planar white light with good color uniformity can be obtained.

The array unit of the present embodiment was actually manufactured, and the luminance distribution was measured by the method described above.
The dimensions of each part of the array unit were as follows.
Chip size of light emitting diodes 12R, 12G, 12B: vertical and horizontal 9mm, height 4.5mm
Distance between centers of each light emitting diode unit 20: 43.5 mm
Thickness of diffusing material 16: 2.0 mm
Height of the central part 14B of the reflector 14: 20.1 mm
Height of upper part 14C of reflector 14: 13.0mm
The width of the bottom surface of the array unit: 25.8 mm
The width of the upper surface of the array unit: 38.9 mm
Array unit length: 150.6mm
Fixing member 13 thickness: 1.0 mm
Thickness of diffusion sheet 15: 0.24 mm

  In the above dimensions, the width and length of the array unit are smaller than the dimensions of the configuration of FIG. 11C described above, but the 45 measurement points shown in FIG. Fits on top of array unit. Also in this case, the measurement points in FIG. 12 are arranged such that column 5 and row C are on the center line in the length direction and the center line in the width direction of the array unit, respectively.

In the array unit of the present embodiment, the red luminance distribution is shown in FIG. 17A, the green luminance distribution is shown in FIG. 17B, and the blue luminance distribution is shown in FIG. 17C.
FIG. 14D shows the result of normalizing the calculated value of the ratio of the red luminance value to the blue luminance value so that the ratio of the luminance value at the center line in the width direction of the array unit is 1.

17A to 17C, it can be seen that the luminance peaks of the three colors are in the vicinity of the center line, and the luminance distributions of the three colors are almost the same.
Moreover, when FIG. 17D is seen, the maximum value is 1.02 and the minimum value is 0.94, which is close to 1.
Thereby, it turns out that plane white light with favorable color uniformity is obtained.

  That is, the diffusion sheet 15 is provided above the light emitting diodes 12R, 12G, and 12B in parallel to the bottom surface, and the emission surfaces of the outer light emitting diodes 12R and 12B are inclined with respect to the bottom surface at an inclination angle α = 30 ° to form an array. It can be seen that even when the unit is configured, planar white light with good color uniformity can be obtained.

  It can be seen that even when the cross-sectional shape of the diffusion sheet 15 and the inclination angle of the exit surfaces of the outer light emitting diodes 12R and 12B are changed, planar white light with good color uniformity can be obtained.

  In addition, it is desirable that the inclination angle of the emission surface of the outer light emitting diodes 12R and 12B is in the range of 10 ° to 80 °.

  The light source device of each embodiment described above can be used for illumination, projector light source, backlight device for color liquid crystal display device, and the like.

For example, the light source device of each of these embodiments is applied to a backlight device, and a color liquid crystal display device includes a transmissive color liquid crystal display panel and a backlight device provided on the back side of the color liquid crystal display panel. Can be configured.
When applied to a backlight device for a color liquid crystal display device, the backlight device is configured by arranging the light emitting diode units 20 or the array units in a matrix, for example, as shown in FIG.

FIG. 18 shows a schematic configuration diagram (disassembled perspective view) of one embodiment of such a color liquid crystal display device.
A color liquid crystal display device 100 shown in FIG. 18 includes a transmissive color liquid crystal display panel 110 and a backlight unit 140 provided on the back side of the color liquid crystal display panel 110.

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. A thin film transistor (TFT) 116 as a switching element and a pixel electrode 117 are formed on the TFT substrate 111 in a matrix.
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.
The counter electrode substrate 112 has a counter electrode 118 and a color filter 119 formed on the inner surface thereof.

  Although not shown, the color filter 119 is divided into segments corresponding to the respective pixels. For example, it is divided into three segments of three primary colors, a red filter, a green filter, and a blue filter.

  In this color liquid crystal display device 100, the transmissive color liquid crystal display panel 110 having such a configuration is sandwiched between two polarizing plates 131 and 132, and the backlight unit 140 irradiates white light from the back side in an active state. By driving in a matrix system, a desired full color image can be displayed.

The backlight unit 140 illuminates the color liquid crystal display panel 110 from the back side. As shown in FIG. 18, the backlight unit 140 includes a light source, a backlight device 120 that emits white light from a light irradiation surface 120 a by mixing white light emitted from the light source, and light of the backlight device 120. It is comprised from the diffusion plate 141 laminated | stacked on the output surface 120a.
The diffusing plate 141 diffuses the white light emitted from the light emitting surface 120a to make the luminance uniform in the surface emission.
When the color liquid crystal display device 100 shown in FIG. 18 is configured using the backlight light source device 40 shown in FIGS. 8 to 10, the diffusion plate 34 shown in FIGS. 9 and 10 is replaced with the diffusion plate 141 shown in FIG. It becomes.

The backlight device 120 is configured by arranging a light emitting diode group including light emitting diodes of three colors R, G, and B in a matrix, not shown.
As a result, each light emitting diode group emits light efficiently, so that the luminance of the image displayed on the color liquid crystal display panel 110 can be sufficiently ensured.
In addition, since the brightness of the image can be sufficiently secured, it is possible to display the image with the same brightness as that of the conventional configuration with less energy.

In each of the above-described embodiments, the chips of the respective light emitting diodes 12R, 12G, and 12B are directly arranged on the substrate 11, so-called bare chip mounting. However, the packages of the respective light emitting diodes 12R, 12G, and 12B are mounted. May be.
In this case, the light emitting diode unit (light mixer) may be configured by covering the package of each of the light emitting diodes 12R, 12G, and 12B with a diffusion sheet and surrounding the periphery with a reflecting material.

  As in the above-described embodiments, in the case of the bare chip mounting in which the chips of the respective light emitting diodes 12R, 12G, and 12B are directly arranged on the substrate 11, the heat dissipation can be improved. There is an advantage that the light emission efficiency of the light emitting diodes 12R, 12G, and 12B can be increased.

Further, in each of the above-described embodiments, the light emitting diode unit is configured by three light emitting diodes 12R, 12G, and 12B of three colors one by one. However, in the present invention, the light emitting diode unit is configured. Other configurations are possible for the emission color and number of light emitting diodes.
For example, a light emitting diode unit may be configured by providing a plurality of light emitting diodes of at least a part of light emitting colors, or using light emitting diodes of two light emitting colors or four or more light emitting colors.

The method of inclining the emission surface of the light emitting diodes in the light emitting diode unit is not limited to the configuration in which the light emitting diodes outside the three light emitting diodes in one row are inclined as in the above-described embodiments. The configuration of is also possible.
When two light emitting diodes are used, for example, a configuration in which the two light emitting diodes are inclined from the bottom surface so as to face each other is conceivable.
When four light emitting diodes are used, for example, a configuration in which two light emitting diodes are arranged vertically and horizontally and inclined from the bottom surface toward the center point side can be considered.
When using 5 light emitting diodes, place one on the center and one on each of the front, back, left, and right sides of the light emitting diodes so that the other four light emitting diodes face the inside. The structure which inclines from a bottom face can be considered.
In either configuration, the emission surface of the plurality of light emitting diodes is inclined so as to face the inside.

  Furthermore, in each of the embodiments described above, a light emitting diode (LED) is used as the light emitting element. However, in the present invention, the light source device may be configured using other light emitting elements. For example, a semiconductor laser or the like can be used as the light emitting element.

  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 source device of one embodiment of this invention. A is a top view of the photodiode unit of the light source device of FIG. B is a cross-sectional view of the photodiode unit of FIG. 2A. It is a top view which shows arrangement | positioning of the light emitting diode unit in the light source device (array unit) of other embodiment of this invention. It is sectional drawing of the part of the light emitting diode unit of the light source device (array unit) of other embodiment of this invention. It is a side view of the array unit of FIG. FIG. 5 is a cross-sectional view of a portion between light emitting diode units of the array unit of FIG. 4. It is another side view of the array unit of FIG. It is a top view which shows arrangement | positioning of the array in a backlight apparatus. It is sectional drawing of the screen vertical direction of a backlight apparatus. It is sectional drawing of the screen horizontal direction of a backlight apparatus. AC is a schematic block diagram (cross-sectional view) of each structure of the light source device which measured luminance distribution. It is a top view which shows arrangement | positioning of the measurement point of luminance distribution. AD is a luminance distribution of the configuration shown in FIG. 11A. AD is a luminance distribution of the configuration shown in FIG. 11B. A to D are luminance distributions having the configuration shown in FIG. 11C. It is a schematic block diagram (sectional drawing) of the light source device (array) of further another embodiment of this invention. A to D are luminance distributions of the configuration shown in FIG. It is a schematic block diagram (disassembled perspective view) of one form of the color liquid crystal display device provided with the light source device as a backlight light source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light source device, 11 Substrate, 12R, 12G, 12B Light emitting diode, 13 Fixing material, 14, 17, 31, 32 Reflective material, 15 Diffusion sheet, 16, 34 Diffusion plate, 30, 50 Light source device (array unit), 40 Backlight device, 100 color liquid crystal display device

Claims (7)

A light source device comprising one light emitting element group composed of at least two types of light emitting elements, and comprising the light emitting element group,
In each of the light emitting element groups, the light emitting elements constituting the light emitting element group are inclined so that the emission surfaces of the light emitting elements face inward,
A reflective material having an opening above is provided to cover the entire light emitting elements constituting the light emitting element group, and a diffusion sheet made of a diffusion material is provided above the light emitting elements. A light source device.   The light source device according to claim 1, wherein the diffusion sheet is formed in an X shape intersecting above the light emitting element.   2. The light emitting element group according to claim 1, wherein each of the light emitting element groups includes at least a light emitting element having a red light emitting color, a light emitting element having a green light emitting color, and a light emitting element having a blue light emitting color. Light source device.   Each of the light emitting element groups has a row in which a light emitting element having a red light emitting color, a light emitting element having a green light emitting color, and a light emitting element having a blue light emitting color are sequentially arranged one by one. The light emitting elements of the red light emitting color and the light emitting element of the blue light emitting color are inclined so as to face inward with respect to the light emitting elements of the green light emitting light emitting elements at the center of each row. The light source device according to claim 3.   5. The light source device according to claim 4, wherein an inclination angle with respect to an emission surface of a light emitting element located at the center of an emission surface of the light emitting element located outside each row is in a range of 10 ° to 80 °.   The light source device according to claim 1, wherein the light emitting element is a light emitting diode. A display for displaying an image;
A light source device that illuminates the display unit from the back side;
The light source device includes one light emitting element group composed of at least two types of light emitting elements, and in each of the light emitting element groups, the emission surface of each light emitting element constituting the light emitting element group faces inward. And a reflective material having an opening above the light emitting element that covers the entire light emitting element constituting the light emitting element group, and a diffusing material is provided above the light emitting element. Display device.

Images