JP2008159401A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make color irregularity inconspicuous by increasing a red color mixing property in a lighting system using three-color LEDs, and to prevent cost from increasing. <P>SOLUTION: In this lighting system 1, a red LED, a green LED and a blue LED are used for a set of LED group; a plurality of sets of LED groups 3 and 4 are continuously arranged along one side surface 2a being an incident surface of a light guide plate 2; and illumination is carried out by using light emitted from the respective LEDs. The red LEDs (R) of at least two LED groups 3 and 4 adjacent to each other within the plurality of LED groups 3 and 4 are arranged side-by-side with each other to increase the red color mixing property most sensible by human eyes, whereby chromaticity irregularity is made hardly visible. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lighting device in which a plurality of sets of LED groups are arranged in a group of red LEDs, green LEDs, and blue LEDs, which are single-color light emitting diodes (LEDs), and illumination is performed with light emitted from each of the LEDs. About.

Conventionally, light emitting diodes are generally referred to as LEDs and are frequently used as light sources for various displays. The emission color of the LED is generally a single color such as red (R), green (G), blue (B), etc., but various illumination colors can be obtained by combining a plurality of single color LEDs having different emission colors and additive color mixing. it can.
For example, white illumination light can be obtained by combining a red LED that emits red light, a green LED that emits green light, and a blue LED that emits blue light, and additively mixing the emission colors.

  For example, Patent Document 1 describes an exposure apparatus that exposes a photosensitive material with slit rays to form an image. As a light source system that is an illumination apparatus, as shown by R, G, and B in FIG. When the red LED, the green LED, and the blue LED are linearly arranged in the same order, illuminance unevenness and color unevenness corresponding to the arrangement pitch of the LEDs occur. Therefore, as shown in FIG. 7, LEDs of three colors of R, G, and B are arranged close to each other to form a light emitting element group 15, and the light emitting element group 15 is arranged at a predetermined pitch along the line direction. It also describes reducing unevenness and color unevenness.

Also, as a backlight illumination device of a liquid crystal display device, for example, as shown in FIG. 8, along one side surface 10 a serving as an incident surface of a light guide plate (light guide) 10 made of a translucent material, R, G, An LED group (unit) 11 in which LEDs of three colors of red, green, and blue shown by B are arranged close to each other at a predetermined interval is often used. In this illuminating device, each of the R, G, and B light emitted from the three color LEDs of each LED group 11 is incident on the light guide plate 10 and repeatedly reflected within the light emitting plate 10 as shown by the broken line. It diffuses and emits illumination light toward the front side of the paper, and planar illumination with additively mixed white light is performed.

  However, in such a conventional lighting device, since the three color LEDs are arranged in the order of “RGB RGB”, the left portion of the left and right LED groups 11 in FIG. 8 is strongly reddish, and the right part is weakly reddish. There was a tendency for color unevenness to occur. This seems to be because the most sensitive color to human eyes is red, as can be seen from the McAdam ellipse.

In order to improve the color unevenness in the backlight illumination device of such a liquid crystal display device, for example, in Patent Document 2, as shown in FIG. 9 or FIG. Along the common wiring board 21, R, G, and B, which are LEDs of three colors of red, green, and blue, are linearly arranged in the order of “RBGRBGGBRGB” or “BGRBGRGBRGB”, and the color arrangement of each LED is It has been proposed to be symmetrical with respect to the center C in the arrangement direction.

Japanese Patent No. 3411380 (paragraphs 0040 and 0087, FIGS. 5 and 12) Japanese Patent Laying-Open No. 2006-66338 (paragraphs 0015 and 0028, FIGS. 2 and 5)

By arranging the three color LEDs symmetrically in this way, the color mixing property and chromaticity distribution in the plane from which the illumination light of the light guide plate 20 is emitted become symmetrical, and even if there is some color unevenness, there is a sense of incongruity. In the case of the example shown in FIG. 9, the red corners of the left and right lower corners are strongly reddish, and in the case of the example shown in FIG. There is a problem that the degree of unevenness is not sufficiently improved.
Moreover, although the light source unit by LED of three colors is generally marketed as a unit in which red LED, green LED, and blue LED are arranged in order, it cannot be used and left and right as shown in FIG. 9 or FIG. There is also a problem that it is expensive to manufacture a symmetrical array of LEDs exclusively.

  The present invention has been made in order to solve the above-described problems, and increases the color mixing property of red in the illumination device using the above-described three-color LEDs so that the color unevenness is not noticeable, and the cost is reduced. The purpose is not to be up.

  In order to achieve the above-mentioned object, the present invention provides a lighting device in which a plurality of LED groups are arranged in a row, with a red LED, a green LED, and a blue LED as a set, and illumination is performed with light emitted from each LED. The red LEDs of at least two adjacent LED groups among the plurality of LED groups are arranged side by side.

The LEDs of the two adjacent LED groups may be arranged in the order of blue LED, green LED, and red LED in one LED group, and in the order of red LED, green LED, and blue LED in the other LED group.
Alternatively, the LEDs of the two adjacent LED groups may be arranged in the order of green LED, blue LED, and red LED in one LED group, and red LED, blue LED, and green LED in the other LED group. .

The plurality of sets of LED groups may be arranged so that light emitted from each LED is incident on one side surface of a light guide plate made of a translucent material.
The plurality of LED groups may be at least four LED groups, and the four LED groups may be arranged in two rows symmetrically in two rows, and so that the red LEDs of each LED group are adjacent to each other. Good.
It is desirable to perform illumination by mixing the emitted light of the plurality of sets of LEDs through a diffusion plate or a diffusion sheet.

  In the illumination device according to the present invention, the red LEDs of at least two adjacent LED groups of the plurality of sets of LED groups are arranged side by side, so that the red color mixing property is increased and the most sensitive red chromaticity unevenness is observed in human eyes. It becomes difficult to visually recognize and good illumination light with little chromaticity unevenness can be obtained. In addition, a general LED unit in which LEDs of three colors are arranged in RGB order or RBG is used as each LED group, and one of two adjacent LED units is reversed left and right to arrange red LEDs next to each other. Therefore, it is not necessary to manufacture a special LED array, and the cost is not increased.

Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings.
FIG. 1 is a plan view showing a first embodiment of a lighting device according to the present invention, and FIG. 2 is a perspective view thereof.
The lighting device 1 includes a red LED (R), a green LED (G), and a blue LED (on a side surface 2a serving as an incident surface of a light guide plate (light guide) 2 made of a light transmitting material such as glass or acrylic. B) are arranged in this order, and two sets of LED groups 3 and 4 are arranged as a set of LED groups, and the red LEDs (R) of the two adjacent LED groups 3 and 4 are arranged side by side. ing. Therefore, the color arrangement of each LED by the LED groups 3 and 4 is “BGR RGB”. Actually, each of the LED groups 3 and 4 constitutes an LED unit in which three LEDs are provided adjacent to each other on a wiring board, but the wiring board and the like are not shown.

In this illumination device 1, the light emitted from each LED of the two LED groups 3 and 4 is incident on the light guide plate 2 and diffused in the emission plane as indicated by a broken line while repeating reflection inside the light guide plate 2. In 1, the illumination light is emitted toward the front side of the paper (upward in FIG. 2), and planar illumination with additively mixed white light is performed. If a minute prism or an uneven pattern is formed on one or both of the upper and lower surfaces of the light guide plate 2, it is possible to more uniformly diffuse the incident light.
Although the color arrangement of the left and right LED groups 3 and 4 is symmetric, it is only necessary that one of two LED units of the same RGB arrangement is horizontally reversed with respect to the other so that red LEDs are adjacent to each other.

According to this lighting device, since the red LEDs (R) of two adjacent LED groups 3 and 4 are arranged side by side, the red color mixing property is increased, and the red chromaticity unevenness most sensitive to human eyes is increased. Is difficult to visually recognize, and good illumination light with little chromaticity unevenness can be obtained. Moreover, since the LED groups 3 and 4 can use the general LED unit of the same color arrangement as mentioned above, it is not necessary to manufacture a special LED array and the cost is not increased.

The color arrangement of the two LED groups 3 and 4 is such that one LED group 3 is in the order of green LED (G), blue LED (B), and red LED (R), and the other LED group 4 is red LED (R). The blue LED (B) and the green LED (G) may be arranged in this order. In this case, the color arrangement of each LED by the LED groups 3 and 4 is “GBR RBG”.
Furthermore, although the LED groups 3 and 4 have different color arrangement configurations, the color arrangement may be “GBR RGB” or “BGR RBG”.

FIG. 3 is a plan view showing a second embodiment of the illumination device according to the present invention, and the same reference numerals are given to portions corresponding to those in FIG.
As in the first embodiment, the illuminating device 5 includes a red LED (R), a green LED (G), and a blue LED (B) arranged in this order along one side surface 2a that is an incident surface of the light guide plate 2. 4 sets of LED groups 3, 4, 3 and 4 are arranged in a line, and a pair of adjacent LED groups 3 and 4 are arranged adjacent to each other. Arranged. The LED group 3 is inverted from the left and right of the LED group 4. Therefore, the color arrangement of each LED by the LED groups 3, 4, 3, and 4 is “BGR RGB BGR RGB”.

This lighting device 5 also provides the same effects as the lighting device 1 of the first embodiment described above. The illumination area is about twice that of the illumination device 1.
Also in this embodiment, as in the case of the first embodiment, the color arrangement of each LED by the LED groups 3, 4, 3, and 4 may be “GBR RBG GBR RBG” or the LED group. Although 3 and 4 have different color arrangement configurations, they may be “GBR RGB GBR RGB” or “BGR RBG BGR RBG”.

  If a larger number of LED groups 3 and 4 are arranged in the same manner, a wider area can be illuminated. Further, the LED groups 3 and 4 may be arranged in a plurality of rows. In each of the above embodiments, the light guide plate 2 is used to illuminate the surface by mixing the light emission colors of the three colors of LEDs. However, the light guide plate 2 is not essential, and the LED groups 3 and 4 arranged in a line. It is also possible to perform slit illumination or to perform surface illumination by arranging the LED groups 3 and 4 in a plurality of rows. Further, it is possible to mix colors using a diffusion (scattering) plate or a diffusion sheet.

4 and 5 are plan views showing third and fourth embodiments of the lighting device according to the present invention, and the same reference numerals are given to portions corresponding to those in FIG.
The lighting device 6 shown in FIG. 4 has a red LED (R), a green LED (G), and a blue LED (B) left on the support plate 30 in the same manner as the LED groups 3 and 4 of the first embodiment described above. LED group 4 composed of LED units arranged in close proximity to each other in this order and LED group 3 obtained by horizontally inverting the LED group are arranged adjacent to each other in two rows with the red LEDs (R) next to each other. Irradiates emitted light to the near side perpendicular to the paper surface.

Moreover, the illuminating device 7 shown in FIG. 5 includes an LED group 9 composed of LED units in which red LEDs (R), blue LEDs (B), and green LEDs (G) are arranged close to each other in this order from the left. LED groups 8 that are horizontally reversed are arranged adjacent to each other in two rows with the red LEDs (R) next to each other. That is, in these illuminating devices 6 and 7, LEDs of three colors are two-dimensionally arranged.
Also in these embodiments, as in the case of the first and second embodiments described above, the color arrangements of the LEDs of the LED groups 3 and 4 and the LED groups 8 and 9 are different from each other in the arrangement direction (left and right in the figure). If the red LEDs (R) are adjacent to each other on the side adjacent to (direction), the order of the LEDs of other colors may be changed as appropriate.

In addition, the arrangement of the LED groups is not limited to four, but a group of LED groups as shown in FIG. 4 or FIG. It is also possible to perform illumination over a wide area.
Furthermore, a more uniform white illumination light can be obtained by providing a diffusion (scattering) plate or a diffusion sheet above the plurality of LED groups to add and mix the emitted light of the three colors of LEDs. .

The illumination device according to the present invention is suitable for a backlight illumination device of a field liquid crystal display device of a field sequential drive type or a type using a normal color filter.
In the case of a backlight lighting device for a field sequential drive type color liquid crystal display device, the R, G and B LEDs of each LED group constituting the same do not emit light at the same time, but emit light sequentially in a predetermined cycle. A one-frame screen is formed in a period in which each color LED sequentially emits light once. Therefore, in this case, the light emitted from the R, G, and B LEDs is not mixed at the same time, but is mixed by the afterimage of the human eye. The illuminating device according to the present invention includes an LED in which R, G, and B LEDs of each LED group sequentially emit light in this manner.

  The illumination device according to the present invention is not limited to a backlight illumination device for a color liquid crystal display device, but can be used for illumination devices for slit exposure, illumination devices for various displays, and guidance.

It is a top view which shows 1st Embodiment of the illuminating device by this invention. It is the perspective view similarly. It is a top view which shows 2nd Embodiment of the illuminating device by this invention. It is a top view which shows 3rd Embodiment of the illuminating device by this invention. It is a top view which shows 4th Embodiment of the illuminating device by this invention. It is a top view which shows an example of the conventional illuminating device using 3 color LED. It is a top view which shows the example of improvement similarly. It is a top view which shows an example of the conventional illuminating device for backlights using LED of 3 colors. It is a plane road figure showing the example of improvement similarly. It is a top view which similarly shows the example of a different arrangement | sequence of the LED.

Explanation of symbols

1, 5, 6, 7; Illumination device 2: Light guide plate (light guide)
2a: One side surface (incident surface) 3, 4, 8, 9: LED group 30: Support plate R: Red LED G: Green LED B: Blue LED

Claims (6)

In a lighting device that arranges a plurality of LED groups in a row with a red LED, a green LED, and a blue LED as a set of LED groups, and illuminates with the emitted light of each LED,
An illumination device, wherein red LEDs of at least two adjacent LED groups among the plurality of sets of LED groups are arranged side by side.   The LEDs of the two adjacent LED groups are arranged in the order of blue LED, green LED, and red LED in one LED group, and in the order of red LED, green LED, and blue LED in the other LED group. The lighting device according to claim 1.   The LEDs of the two adjacent LED groups are arranged in the order of green LED, blue LED, and red LED in one LED group, and in order of red LED, blue LED, and green LED in the other LED group. The lighting device according to claim 1.   The illumination according to any one of claims 1 to 3, wherein the plurality of sets of LED groups are arranged so that light emitted from each LED is incident on one side surface of a light guide plate made of a translucent material. apparatus.   The plurality of LED groups are at least four LED groups, and the four LED groups are arranged in two rows symmetrically in two rows, and the red LEDs of each LED group are arranged adjacent to each other. The lighting device according to any one of claims 1 to 4, wherein   6. The illumination device according to claim 1, wherein illumination is performed by mixing light emitted from the plurality of sets of LED groups through a diffusion plate or a diffusion sheet. 6.

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