JP2010205881A - White adjusting device of led backlight - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a white adjusting device of an LED backlight capable of reducing the time required for white adjusting of the LED backlight. <P>SOLUTION: A plurality of light sources including a plurality of LEDs are arranged on the same level, and white light generated by colored lights of each LED of the light sources is irradiated from the back surface of a display panel, in the white adjusting device 1 of the LED backlight. The white adjusting device 1 includes an imaging means and an adjusting means. The imaging means is provided with a plurality of optical fibers 2, wherein the white light from the light sources is made incident to one end thereof, so as to face each light source one to one, and images the light emitted from the other end of a plurality of optical fibers. The adjusting means so adjusts luminance and/or chromaticity as to be uniform in the light emitting surface of the backlight, based on a two-dimensional image obtained by the imaging means. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an LED backlight white color adjusting device that is disposed on the back side of a light-transmissive display panel such as a liquid crystal display panel and irradiates light on the display panel.

  As an example of a flat display device, for example, a liquid crystal display device including a light-transmissive liquid crystal display panel generally has a backlight disposed on the back side of the liquid crystal display panel. This backlight includes a fluorescent lamp such as a cold cathode tube as a light source, and adjusts the characteristics of light emitted from the fluorescent lamp to irradiate light on the back side of the liquid crystal display panel. The irradiated light passes through the liquid crystal display panel, so that an image is displayed in a visible state on the front side of the liquid crystal display panel.

  As a light source incorporated in such a backlight, a light emitting diode (LED) has recently been used in addition to the fluorescent lamp described above.

  FIG. 3 is a diagram showing a schematic configuration of a backlight using LEDs as light sources. The LED backlight 20 is provided with a plurality of light sources 22 including a red LED 22R, a green LED 22G, and a blue LED 22B vertically and horizontally, and white light is generated by mixing colored light by the LEDs 22R, 22G, and 22B. It has become.

  Further, the light from each light source 22 is diffused by the light diffusing plate 23 so that the dot image of each light source 22 is erased, and the light emitted from the light diffusing plate 23 has uniform in-plane luminance. In this state, a light transmission type display panel such as a liquid crystal display panel (not shown) is irradiated. In FIG. 3, the number of the light sources 22 is reduced to simplify the drawing, but actually, for example, the LED backlight 20 disposed on the back surface of the 52-inch liquid crystal display panel. In this case, the number of light sources 22 provided is 1152 in total of 24 × 48.

  Such a light source 22 composed of a plurality of LEDs 22R, 22G, and 22B has a problem in that the luminance and chromaticity vary greatly even when manufactured in the same lot, and therefore, normally white light emitted from each light source 22 is used. Adjustment is performed using a white adjustment device 30 as illustrated so that the luminance and chromaticity of light are uniform.

  The white color adjusting device 30 includes a CCD camera 31 and an adjusting unit 34. The CCD camera 31 as an image pickup means is a so-called two-dimensional chromaticity luminance meter, and tristimulus values of red, green, and blue (3 required for equalizing the color stimulus of the sample in the three-color color system). A plurality of color CCD image sensors 32 each having an optical filter having a spectral transmission characteristic capable of obtaining an amount of the original stimulus) are two-dimensionally arranged, and two-dimensional image photographing is possible. The color CCD image sensor 32 photoelectrically converts incident light into an image signal corresponding to the amount of light and outputs the image signal. The objective lens 33 disposed on the light receiving surface side of the color CCD image sensor 32 has a focus adjustment function for adjusting the focus of the image according to the distance to the measurement object.

  In this case, the LEDs 22R, 22G, and 22B of the LED backlight 20 and the light sources 22 are sequentially switched to emit light, that is, red light, green light, and blue light are sequentially emitted in a single color, and the light emitting surface 20a of the LED backlight 20 at that time. Are respectively imaged by the CCD camera 31, so that a two-dimensional tristimulus value image (two-dimensional image) can be obtained. Normally, the number of the color CCD image sensors 32 provided in the CCD camera 31 is configured to be 1,000,000 in the vertical direction and 1,000 in the horizontal direction (1 million pixels).

  The adjusting unit 34 calculates the luminance and chromaticity from the RGB pixel values (tristimulus values) in each pixel of the two-dimensional image of the light emitting surface 20a imaged by the CCD camera 31, and the calculated luminance and chromaticity are calculated. A process of adjusting and resetting the light emission times and the like of the red LED 22R, the green LED 22G, and the blue LED 22B included in each light source 22 is executed so as to achieve the target luminance and the target chromaticity. Such processing is repeatedly executed until the luminance and chromaticity within the light emitting surface 20a of the LED backlight 20 reach predetermined values, that is, until the luminance and chromaticity of white light emitted from each light source 22 become uniform. Thus, white adjustment (white balance adjustment) of the LED backlight 20 is performed.

  Usually, such white adjustment of the LED backlight 20 is performed in a dark room where light does not enter from the outside in order to improve measurement accuracy. In addition, the following patent document is mentioned as a prior art document relevant to this invention.

JP 2007-329591 A

  However, when the luminance and chromaticity corresponding to each light source 22 is calculated from the two-dimensional image of the light emitting surface 20a captured by the CCD camera 31 by the adjusting means 34, as described above, regardless of the number of light sources 22 (1152). Since the two-dimensional image data for the number of pixels (1 million pixels) of the color CCD image sensor 32 provided in the CCD camera 31 is fetched and calculation for the number of pixels is required, the processing takes a lot of time, As a result, the time required for white adjustment of the LED backlight is increased.

  Accordingly, the problem to be solved by the present invention is to provide an LED backlight white color adjusting device capable of shortening the time required for white color adjustment of the LED backlight.

  In order to solve the above-described problems, the present invention provides a plurality of light sources including a plurality of LEDs arranged on the same plane, and irradiates white light generated by the colored light of each LED of the light source from the back side of the display panel. A white color adjustment device for an LED backlight, wherein a plurality of optical fibers on which one end of white light from the light source is incident are provided so as to face each of the light sources on a one-to-one basis, and the other ends of the plurality of optical fibers An imaging unit that images light emitted from the imaging unit, and an adjustment unit that adjusts the luminance and / or chromaticity to be uniform within the light emitting surface of the backlight based on a two-dimensional image obtained by the imaging unit. The gist is that it is provided.

  According to the white color adjustment device for the LED backlight having such a configuration, a plurality of optical fibers on which white light from each light source of the LED backlight is incident on one end are provided so as to face each light source in a one-to-one relationship, Since the image pickup means for picking up the light emitted from the other ends of the plurality of optical fibers is provided, the two-dimensional image obtained by the image pickup means is the number of light sources of the LED backlight (number of optical fibers). And at least the same number of pixels. Therefore, for example, when calculating the luminance and chromaticity corresponding to each light source based on a two-dimensional image (1 million pixels) obtained by imaging all of the light emitting surface of the LED backlight as in the above-described prior art. In comparison, since the brightness and chromaticity corresponding to each light source are simply calculated based on a two-dimensional image having at least the number of pixels (1152 pixels) corresponding to the number of each light source (1152), the time required for this processing is conventionally Can be shortened. Thereby, it is possible to shorten the time required for white adjustment of the LED backlight as compared with the prior art.

  In this case, if one end of the plurality of optical fibers is inserted and fixed to a flat plate-shaped incident member disposed to face the light emitting surface of the LED backlight, such incident light is used. By simply disposing the member so as to face the light emitting surface of the LED backlight, it is possible to simply arrange one end of the plurality of optical fibers so as to face each light source on a one-to-one basis.

  Further, if the incident surface of the incident member facing the light emitting surface of the LED backlight is configured to have antireflection treatment, light from each light source of the LED backlight is incident on the incident surface of the incident member. Since the generation of stray light due to reflection at the light source is suppressed, it is possible to eliminate the influence of such stray light and improve the light detection accuracy by each optical fiber disposed to face each light source in a one-to-one relationship. In this case, if the antireflection treatment applied to the incident surface of the incident member is a black matte coating, the antireflection treatment can be easily performed on the incident surface of the incident member.

  Further, if the light-shielding member that shields light from the outside is provided on the outer periphery between the incident member and the LED backlight arranged opposite to each other, It is not necessary to perform white adjustment in a dark room, and it is possible to easily perform white adjustment. In this case, if the light-shielding member is provided integrally with the incident member, it is possible to simply prevent the light from entering from the outside simply by placing the incident member facing the LED backlight. Can be shielded from light.

  If the incident member is provided with a positioning portion for positioning the incident member so that the incident member is disposed at a predetermined position with respect to the light emitting surface of the LED backlight, the LED backlight is provided. One end of each optical fiber provided on the light source and the incident member can be positioned, for example, one-on-one so as to face directly, and the distance between each light source and one end of each optical fiber is also constant. Therefore, it is possible to easily arrange one end of each optical fiber at a predetermined position with respect to each light source with good reproducibility. In this case, if the positioning portion is provided in the light shielding member, the incident member is positioned so as to be disposed at a predetermined position with respect to the light emitting surface of the LED backlight. It is possible to block light from entering between the incident member and the LED backlight.

  If the other ends of the plurality of optical fibers are inserted into and fixed to a flat plate-like emission member arranged opposite to the imaging means, such an emission member is used as the imaging means. The imaging means can easily pick up the emitted light from the other ends of the plurality of optical fibers simply by disposing them facing each other.

  Further, if the exit surface of the exit member facing the image pickup means is configured to have an antireflection treatment, the stray light caused by the light emitted from the other end of the optical fiber being reflected by the lens of the image pickup means, etc. Therefore, the detection accuracy of light emitted from each optical fiber can be improved by eliminating the influence of such stray light. In this case, if the antireflection treatment applied to the emission surface of the emission member is configured to have a black matte coating, the antireflection treatment can be easily applied to the emission surface of the emission member.

  Furthermore, if a light-shielding member that shields light from entering from the outside is provided on the outer periphery between the emission member and the imaging means that are arranged to face each other, a conventional darkroom is provided. This eliminates the need for white adjustment and makes it possible to easily perform white adjustment. In this case, if the light shielding member is provided integrally with the emitting member, light can be easily emitted from the outside simply by mounting the emitting member in front of the lens of the imaging means. The light can be shielded from entering.

  In addition, if the emitting member is provided with a positioning portion that positions the emitting member so that the emitting member is disposed at a predetermined position with respect to the imaging unit, for example, the imaging unit and the emitting unit are arranged. The other end of each optical fiber provided on the member can be positioned so as to be directly opposite, and the distance between the imaging means and the other end of each optical fiber can be made constant. On the other hand, the other end of each optical fiber can be arranged to be opposed to a predetermined position. In this case, if the positioning portion is provided in the light shielding member, the emitting member is positioned so as to be arranged at a predetermined position with respect to the imaging unit, and the arranged emitting member is arranged. It is possible to shield the light from the outside so as not to enter between the imaging means and the imaging means.

  According to the white color adjustment device for an LED backlight according to the present invention, a plurality of optical fibers on which white light from each light source of the LED backlight is incident on one end are provided so as to face each light source in a one-to-one relationship. Since the imaging means for imaging the light emitted from the other end of the plurality of optical fibers is provided, a two-dimensional image having pixels for the number of optical fibers is obtained, and each light source is obtained based on the two-dimensional image. Since only the corresponding luminance and chromaticity are calculated, the time required for this process can be reduced as compared with the conventional case. As a result, the time required for white adjustment of the LED backlight is reduced as compared with the conventional case.

It is the figure which showed schematic structure of the white color adjustment apparatus of the LED backlight which concerns on one Embodiment of this invention. It is the flowchart which showed the procedure of the process of the white adjustment apparatus of FIG. It is the figure which showed schematic structure of the white adjustment apparatus of the LED backlight used conventionally.

  Hereinafter, embodiments of a white color adjusting device for an LED backlight according to the present invention will be described in detail with reference to the drawings.

  First, an LED backlight in which white adjustment is performed by the white adjustment device according to the present invention will be described. As shown in FIG. 1, the LED backlight 20 includes a chassis 21 having a shallow box shape. Inside the chassis 21, a light source 22 including a red LED 22R, a green LED 22G, and a blue LED 22B is provided. A plurality of bottom surfaces 21a are arranged so as to be even in the vertical and horizontal directions. White light is generated by mixing the colored light of the LEDs 22R, 22G, and 22B of the light source 22.

  Further, a light diffusing plate 23 is provided on the front surface of the chassis 21, and the light emitted from each light source 22 is diffused by the light diffusing plate 23 so that the dot image of each light source 22 is erased. It has become. The light emitted from the light diffusing plate 23 has a uniform in-plane luminance, and can be applied to the back surface of a light transmission type display panel such as a liquid crystal display panel (not shown).

  Further, the LED backlight 20 includes an LED lighting circuit 24. The LED lighting circuit 24 includes an LED drive circuit 25 that lights each of the LEDs 22R, 22G, and 22B included in the light source 22, and a memory 26.

  In the memory 26, LED control data for lighting and driving the LEDs 22R, 22G, and 22B is written and stored, and the LED drive circuit 25 reads out the LED control data stored in the memory 26 to read each LED 22R, 22G and 22B are driven to light. In this case, a RAM (Random Access Memory) that can rewrite the LED control data is used as the memory 26.

  The LED drive circuit 25 generates a PWM (Pulse Width Modulation) signal based on the LED control data written in the memory 26, and outputs this to each LED 22R, 22G, 22B of each light source 22. To do. The output PWM signal turns on and off switching elements (not shown) connected to the LEDs 22R, 22G, and 22B included in the light sources 22 to light (flash) the LEDs 22R, 22G, and 22B included in the light sources 22.

  Each LED 22R, 22G, 22B included in each light source 22 has a pulse width set with respect to the period T of the PWM signal output from the LED drive circuit 25, that is, a time during which each LED 22R, 22G, 22B is turned on (on duty time). ) It is turned on during the period t. By changing the on-duty time t, the amount of color light emitted from the LEDs 22R, 22G, and 22B of each light source 22 can be adjusted.

  In this case, the LED control data written in the memory 26 includes an on-duty ratio D (D) obtained by dividing the on-duty time t set for each LED 22R, 22G, 22B of each light source 22 by the period T of the PWM signal. = T / T).

  The on-duty ratios D of the LEDs 22R, 22G, and 22B included in the light sources 22 of the LED backlight 20 can be set independently. For example, the LEDs 22R, 22G, and It is possible to increase / decrease the amount of light of all the colored light 22B or increase / decrease the amount of colored light of only the green LED 22G included in one light source 22. Thereby, each LED22R, 22G, and 22B which each light source 22 has can be adjusted so that the brightness | luminance and chromaticity in the light emission surface 20a of LED backlight may become uniform.

  In FIG. 1, the number of light sources 22 is reduced to simplify the drawing, but in the present embodiment, the LED backlight 20 disposed on the back of the 52-inch liquid crystal display panel. As shown, the number of light sources 22 provided is a total of 1152 (vertical 24 × horizontal 48).

  Next, a white color adjusting device for an LED backlight according to the present invention will be described. As shown in FIG. 1, a white adjustment device (white balance adjustment device) 1 includes an incident member 3 in which incident ends 2 a of a plurality of optical fibers 2 are inserted and fixed, and an optical fiber extending from the incident member 3. LED control based on a two-dimensional image captured by the CCD camera 7 that images the emission surface 5a of the emission member 5 to which the two emission ends 2b are inserted and fixed, the emission surface 5a of the emission member 5 And an adjustment unit 11 that creates data and writes the data in a memory 26 included in the LED lighting circuit 24 of the LED backlight 20.

  The flat incident member 3 is made of a resin or metal plate member having a light shielding property, and when the white color of the LED backlight 20 is adjusted as shown in the drawing, the incident surface 3a is the light emitting surface of the LED backlight 20. It arrange | positions so that it may be substantially parallel with respect to 20a.

  In this case, the incident ends 2a of the same number of optical fibers 2 (1152) as the number of light sources 22 (1152) included in the LED backlight 20 are arranged vertically and horizontally so as to be even with the incident surface 3a of the incident member 3. In addition, when the incident member 3 is arranged so as to face the light emitting surface 2a of the LED backlight 20 as shown in the drawing, the light sources 22 and the incident ends 2a of the optical fibers 2 are in a one-to-one relationship. It is supposed to be arranged so as to face each other.

  Further, the incident surface 3a of the incident member 3 is subjected to antireflection treatment by black matte coating or the like. By performing the antireflection treatment on the incident surface 3a in this way, generation of stray light due to reflection of light from each light source 22 of the LED backlight 20 by the incident surface 3a is suppressed. Thus, it is possible to improve the light detection accuracy by the optical fibers 2 arranged to face the light sources 22 on a one-to-one basis.

  Further, the light shielding member 4 having a hood shape that prevents light from entering the outer periphery between the incident member 3 opposed to adjust the white color of the LED backlight 20 and the LE backlight 20. Is provided. In this case, the light shielding member 4 is attached and fixed so as to be integrated with the incident member 3, and when the incident member 3 is disposed opposite to the LED backlight 20, the front end portion 4 a of the light shielding member 4 becomes the LED. It fits on the outer peripheral surface of the chassis 21 of the backlight 20.

  By providing the light shielding member 4 in this way, light does not enter from the outside between the LED backlight 20 and the incident member 3, so that it is not necessary to perform white adjustment in a dark room as in the prior art, and it is simple. It becomes possible to perform white adjustment work.

  Further, a step portion 4 b is formed at the front end portion 4 a of the light shielding member 4, and the step portion 4 b comes into contact with the chassis 21 of the LED backlight 20. Therefore, when the incident member 3 integrally provided with the light shielding member 4 is attached to the LED backlight 20, the step portion 4b causes the incident member 3 to be incident on the light emitting surface 20a of the LED backlight 20. The incident surface 3a is positioned at a predetermined position.

  By providing the positioning member (step 4b) on the incident member 3 in this manner, the light sources 22 of the LED backlight 20 and the incident ends 2a of the optical fibers 2 of the incident member 6 are in a one-to-one relationship. In addition, the distance between each light source 22 and the incident end 2a of each optical fiber 2 can be made constant, and the incident end 2a of each optical fiber 2 can be easily determined with respect to each light source 22 with good reproducibility. It is possible to arrange them opposite to each other.

  In addition, it is preferable that the inner surface of the light shielding member 4 is also subjected to an antireflection treatment by black matte coating or the like. Also in this case, since the light from each light source 22 of the LED backlight 20 is reflected on the inner surface of the light shielding member 4, the generation of stray light is suppressed. It is possible to improve the light detection accuracy by the optical fibers 2 arranged to face each other one to one.

  Further, the flat emission member 5 is made of a resin or metal plate member having a light shielding property. As shown in the drawing, when the white color of the LED backlight 20 is adjusted, the emission surface 5 a is the objective of the CCD camera 7. It arrange | positions so that it may become substantially parallel with respect to the lens 9. FIG.

  The emission ends 2 b of the optical fibers 2 are arranged vertically and horizontally so as to be even with the emission surface 5 a of the emission member 5. In this case, the emission member 5 is formed to be approximately the same size as the objective lens 9 of the CCD camera 7, and the optical fibers 2 extending from the incidence member 3 are gathered as shown in the figure. In this way, the respective emission ends 2b are inserted into the emission member 5 and fixed.

  Further, the exit surface 5a of the exit member 5 is subjected to antireflection treatment by black matte coating or the like. By performing the antireflection treatment on the emission surface 5a in this way, the generation of stray light due to the light emitted from the emission end 2b of each optical fiber 2 being reflected by the objective lens 9 is suppressed. The detection accuracy of the light emitted from the emission end 2b of each optical fiber 2 can be improved by eliminating the influence.

  Further, a light shielding member 6 having a hood shape is provided on the outer periphery between the emission member 5 and the CCD camera 7 so as to prevent light from entering from the outside. In this case, the light shielding member 6 is attached and fixed so as to be integrated with the emission member 5. When the emission member 5 is disposed opposite to the CCD camera 7, the front end portion 6 a of the light shielding member 6 becomes the lens hood. 10 is fitted to the outer peripheral surface.

  By providing the light shielding member 6 in this way, light does not enter from the outside between the emitting member 5 and the lens hood 10, so that it is not necessary to perform white adjustment in a dark room as in the conventional case, and the white color can be easily obtained. Adjustment work can be performed.

  A step 6 b is formed at the front end 6 a of the light shielding member 6, and this step 6 b comes into contact with the front end of the lens hood 10. Therefore, when the emission member 5 integrally provided with the light shielding member 6 is attached to the lens hood 10 of the CC camera 7, the emission surface of the emission member 5 with respect to the objective lens 9 by the step 6b. 5a is positioned at a predetermined position.

  Thus, by providing the positioning member (step portion 6 b) on the emitting member 5, the emitting end 2 b of each optical fiber 2 inserted and fixed to the emitting member 5 is positioned so as to be directly opposite to the objective lens 9. In addition, the distance between the objective lens 9 and the output end 2b of each optical fiber 2 can be made constant, and the output end 2b of each optical fiber 2 can be easily positioned with respect to the objective lens 9 at a predetermined position with good reproducibility. It is possible to arrange them opposite to each other.

  The inner surface of the light shielding member 6 is preferably subjected to antireflection treatment by black matte coating or the like. Also in this case, since the generation of stray light due to the light emitted from the emission end 2b of each optical fiber 2 being reflected by the inner surface of the light shielding member 6 is suppressed, the influence of such stray light is eliminated and the optical fiber 2 is eliminated. It is possible to improve the detection accuracy of light emitted from the emission end 2b.

  The CCD camera 7 as an imaging means can obtain red, green, and blue tristimulus values (amount of three primary stimuli necessary for equalizing the color stimulus of the sample in the three-color color system). A plurality of color CCD image sensors 8 each having an optical filter having spectral transmission characteristics are two-dimensionally arranged, and two-dimensional image shooting is possible.

  As an optical filter provided in such a color CCD image sensor 8, three types of R and G having spectral transmission characteristics approximating to a color matching function (CIE 1931 RGB color system) defined by the International Commission on Illumination (CIE). , B filters, and three types of X, Y, and Z filters having spectral transmission characteristics that approximate the color matching function (CIE1931XYZ color system) defined by the International Commission on Illumination (CIE) are applicable. .

  The objective lens 9 disposed on the light receiving surface side of the color CCD image sensor 8 has a focus adjustment function for adjusting the focus of the image according to the distance to the measurement object. Is covered with a lens hood 10. In this case, the number of color CCD image sensors 8 provided in the CCD camera 7 is configured to be a total of 10,000 (10,000 pixels), which is 100 × 100 in width, and the number of optical fibers 2 described above (1152). Has a number sufficiently higher than.

  The adjusting means 11 emits light from the red LED 22R, the green LED 22G, and the blue LED 22B included in each light source 22 of the LED backlight 20, based on the luminance and chromaticity obtained from the two-dimensional image of the emission surface 5a imaged by the CCD camera 7. A process for adjusting the time and resetting is executed. Such processing is repeatedly executed until the luminance and chromaticity within the light emitting surface 20a of the LED backlight 20 reach predetermined values, that is, until the luminance and chromaticity of white light emitted from each light source 22 become uniform. Thus, white adjustment (white balance adjustment) of the LED backlight 20 is performed.

  The adjusting unit 11 is configured by an operation unit such as a PC (Personal Computer), a monitor, and a keyboard, and includes an adjusting unit 12 and a memory 13. The adjustment unit 12 determines each measurement point (optical fiber emission) based on the RGB pixel value (tristimulus value) in the pixel for each measurement point (optical fiber emission end) 2b of the two-dimensional image of the emission surface 5a captured by the CCD camera 7. End) When the luminance and chromaticity at 2b are calculated, and the calculated luminance and chromaticity are compared with the target luminance and chromaticity stored in the memory 13, and these values are misaligned. Performs a process of newly creating LED control data for driving the LEDs 22R, 22G, and 22B of the light sources 22 so that the calculated luminance and chromaticity become the target luminance and the target luminance. In this case, a RAM (Random Access Memory) is used as the memory 13.

  Specifically, the adjustment unit 12 compares the luminance and chromaticity at each measurement point (optical fiber emitting end) 2b with the target luminance and target chromaticity stored in the memory 13, and shifts these values. Is generated, adjustment LED control data (adjustment on-duty ratio D data) corresponding to the amount of deviation is created, and initial LED control data (stored in the memory 26 included in the LED backlight 20) is generated. The process of rewriting the initial on-duty ratio (D data) is executed.

  For example, when the emitted light (white light) at a certain measurement point (optical fiber output end) 2b is reddish, that is, the colored light of the red LED 22R incident on the incident end 2a of the optical fiber 2 corresponding to this measurement point 2b. Is larger than normal, the adjustment unit 12 uses the adjustment LED control data obtained by reducing the on-duty ratio D of the PWM signal output to the red LED 22R in order to reduce the amount of color light emitted from the red LED 22R. A process of creating and writing this in the memory 26 of the LED lighting circuit 24 is executed. Therefore, the adjustment means 9 repeats such adjustment until the brightness and chromaticity of the white light emitted from each light source 22 of the LED backlight 20, that is, the light emitted from the emission end 2 b of each optical fiber 2 becomes uniform. Execute.

  Next, a procedure of processing executed by the above-described white adjustment device 1 will be described using the flowchart shown in FIG. In this case, as shown in the figure, prior to the white main adjustment (white balance main adjustment) of the LED backlight 20 in steps S5 to S7, the white temporary adjustment (white balance temporary adjustment) of the LED backlight 20 in steps S1 to S4. Adjustment) is executed by the adjusting means 11.

  In the white balance temporary adjustment, first, only the red LED 22R of each light source 22 of the LED backlight 20 emits monochromatic light, and red light is incident on the incident end 2a of each optical fiber 2, and red light is emitted from the output end 2b of each optical fiber. The CCD camera 7 picks up the emission surface 5a of the emission member 5 in the state thus obtained, and stores the two-dimensional image in the memory 13 of the adjustment means 11 (step S1). In step S1, the red LED 22R of each light source 22 is output from the LED drive circuit 25 based on the initial LED control data (initial on-duty ratio D data) for the red LED 22R stored in the memory 26 of the LED lighting circuit 24. Light is emitted by the output PWM signal.

  Next, only the green LED 22G of each light source 22 of the LED backlight 20 emits monochromatic light, and green light is incident on the incident end 2a of each optical fiber 2, and the green light is emitted from the exit end 2b of each optical fiber. The CCD camera 7 images the exit surface 5b of the member 5 for use, and the two-dimensional image is stored in the memory 13 of the adjusting means 11 (step S2). In step S2, the green LED 22G of each light source 22 is output from the LED drive circuit 25 based on the initial LED control data (initial on-duty ratio D data) for the green LED 22R stored in the memory 26 of the LED lighting circuit 24. Light is emitted by the output PWM signal.

  Next, only the blue LED 22B of each light source 22 of the LED backlight 20 emits monochromatic light so that blue light is incident on the incident end 2a of each optical fiber 2 and the blue light is emitted from the output end 2b of each optical fiber. The CCD camera 7 images the exit surface 5a of the member 5 and saves the two-dimensional image in the memory 13 of the adjusting means 11 (step S3). In step S3, the blue LED 22G of each light source 22 is output from the LED drive circuit 25 based on the initial LED control data (initial on-duty ratio D data) for the blue LED 22B stored in the memory 26 of the LED lighting circuit 24. Light is emitted by the output PWM signal.

  The initial LED control data (initial on-duty ratio D data) for each LED 22R, 22G, 22B stored in the memory 26 of the LED lighting circuit 24 described above may be stored in the memory 26 in advance. Alternatively, the initial LED control data may be stored in the memory 13 of the adjusting unit 11, and the adjusting unit 11 may write and store the initial LED control data in the memory 26 of the LED lighting circuit 24 before the white balance temporary adjustment. Further, as the initial LED control data, for example, data set so that the on-duty ratios D of the PWM signals respectively output to the LEDs 22R, 22G, and 22B are the same.

  Then, based on the RGB pixel values (tristimulus values) in the pixel for each measurement point (optical fiber emission end) 2b of the two-dimensional image stored in the memory 13 of the adjusting means 11 in steps S1 to S3, each measurement point (tristimulus value) The luminance and chromaticity at the optical fiber output end) 2b are calculated, and the calculated luminance and chromaticity are compared with the target luminance and target chromaticity stored in the memory 13, and a deviation occurs in these values. If so, provisional adjustment LED control data (temporary adjustment on-duty ratio D data) corresponding to the amount of deviation is created, and the initial LED control data (initial on-duty data) stored in the memory 26 of the LED lighting circuit 24 is generated. Ratio D data) and rewritten (step S4).

  Next, all the LEDs 22R, 22G, and 22B included in each light source 22 of the LED backlight 20 are caused to emit light so that white light is incident on the incident end 2a of each optical fiber 2, and white light is emitted from the output end 2b of each optical fiber. The exit surface 5a of the exit member 5 in the exited state is imaged by the CCD camera 7, and the two-dimensional image is stored in the memory 13 of the adjusting means 11 (step S5). In step S5, the LEDs 22R, 22G, and 22B of the light sources 22 are temporarily adjusted for the LEDs 22R, 22G, and 22B that are written and stored in the memory 26 of the LED lighting circuit 24 by the temporary white balance adjustment in steps S1 to S4. Light is emitted by a PWM signal output from the LED drive circuit 25 based on the LED control data (temporary adjustment on-duty ratio D data), whereby the colored light of each of the LEDs 22R, 22G, and 22B is mixed to generate white light. Is generated, and this white light is incident on the incident end 2 a of each optical fiber 2.

  Next, based on the RGB pixel values (tristimulus values) in the pixels for each measurement point (optical fiber output end) 2b of the two-dimensional image stored in the memory 13 in step S5, each measurement point (optical fiber output end) ) The luminance and chromaticity at 2b are calculated, and each light source 22 is set so that the calculated luminance and chromaticity are values within the setting range of the target luminance and target chromaticity stored in the memory 13. LED control data for driving each of the LEDs 22R, 22G, and 22B is created. That is, at each measurement point (optical fiber output end) 2b calculated based on the RGB pixel value (tristimulus value) at the pixel for each measurement point (optical fiber output end) 2b of the two-dimensional image captured by the CCD camera 7. And the target luminance and chromaticity stored in the memory 13 are compared (spec determination) (step S6). If these values are shifted (step S6 ( No)), main adjustment LED control data (main adjustment on-duty ratio D data) corresponding to the amount of deviation is created, and this is temporarily adjusted LED control data (temporary adjustment) stored in the memory 26 of the LED lighting circuit 24 On-duty ratio D data) is rewritten and stored (step S7).

  Step S5, step S6 (No), and step S7, which are these main adjustments, are performed in accordance with RGB pixel values (tristimulus values) in pixels at each measurement point (optical fiber emitting end) 2b of the two-dimensional image captured by the CCD camera 7. The luminance and chromaticity at each measurement point (optical fiber emitting end) 2b calculated based on the above are repeated until the target luminance and chromaticity stored in the memory 11 are obtained (step S6 (Yes)). And when it becomes the value within the setting range of target luminance and target chromaticity (step S6 (Yes)), this adjustment is complete | finished.

  According to the LED backlight white color adjusting device 1 described above, a plurality of optical fibers 2 on which white light from each light source 22 of the LED backlight 20 is incident on the incident end 2a are opposed to each light source 22 on a one-to-one basis. The CCD camera 7 for imaging the light emitted from the emission ends 2b of the plurality of optical fibers 2 is provided, so that a two-dimensional image obtained by the CCD camera 7 is converted into an LED backlight 20. It is possible to have at least as many pixels as the number of the light sources 22, that is, the number of the optical fibers 2.

  Therefore, for example, as described in the related art, the luminance and chromaticity corresponding to each light source 22 are calculated based on the two-dimensional image (1 million pixels) obtained by imaging all of the light emitting surface 20a of the LED backlight 20. Compared with the case where the number of pixels (1152 pixels) corresponding to the number of light sources 22 (1152) as described above, that is, each measurement point (optical fiber output end) 2b of the two-dimensional image of the imaged exit surface 5a. Since only the luminance and chromaticity are calculated with respect to these pixels, the time required for this processing can be reduced as compared with the conventional case. Thereby, it is possible to shorten the time required for white adjustment of the LED backlight 20 as compared with the conventional case.

  In this case, since the incident ends 2a of the plurality of optical fibers 2 are inserted and fixed to a flat plate-shaped incident member 3 disposed to face the light emitting surface 20a of the LED backlight 20, such incident is performed. The incident members 2a of the plurality of optical fibers 2 can be arranged so as to face the light sources 22 on a one-to-one basis simply by arranging the member 3 so as to face the light emitting surface 20a of the LED backlight 20.

  In addition, since the incident surface 3a of the incident member 3 facing the light emitting surface 20a of the LED backlight 20 is subjected to antireflection treatment by black matte coating, the light from each light source 22 of the LED backlight 20 is reflected. Generation of stray light due to reflection on the incident surface 3a of the incident member 3 is suppressed. Therefore, it is possible to improve the light detection accuracy by the optical fibers 2 arranged to face the light sources 22 on a one-to-one basis by eliminating the influence of such stray light.

  Furthermore, since the light shielding member 4 that shields light from entering from the outside is provided on the outer periphery between the incident member 3 and the LED backlight 20, it is necessary to perform white adjustment in a conventional dark room. Therefore, it is possible to easily perform the white adjustment operation. In this case, since the light shielding member 4 is provided integrally with the incident member 3, simply placing the incident member 3 facing the LED backlight 20 can prevent light from entering from the outside easily. Can be shielded from light.

  Further, the incident member 3 is provided with a positioning portion (a step portion 4b of the light shielding member 4) for positioning the incident member 3 so as to be disposed at a predetermined position with respect to the light emitting surface 20a of the LED backlight 20. Therefore, each light source 22 provided in the LED backlight 20 and the incident end 2a of each optical fiber 2 provided in the incident member 3 can be positioned, for example, one-on-one so as to face each other, and each light source The distance between the optical fiber 2 and the incident end 2a of each optical fiber 2 can also be made constant, and the incident end 2a of each optical fiber 2 can be arranged opposite to the predetermined position with respect to each light source 22 with good reproducibility. It becomes possible.

  Since the emission ends 2b of the plurality of optical fibers 2 are inserted and fixed to a flat plate-like emission member 5 arranged to face the CCD camera 7, such an emission member 5 is fixed to the CCD camera. The CCD camera 7 can easily pick up the light emitted from the light emitting ends 2 b of the plurality of optical fibers 2.

  Further, since the exit surface 5a of the exit member 5 facing the CCD camera 7 has been subjected to antireflection treatment by black matte coating, the exit light from the exit end 2b of the optical fiber 2 is converted into the objective lens of the CCD camera 7. Generation of stray light due to reflection at 9 etc. is suppressed. Therefore, it is possible to improve the detection accuracy of light emitted from each optical fiber 2 by eliminating the influence of such stray light.

  Further, since a light shielding member 6 is provided on the outer periphery between the emission member 5 and the CCD camera 7 so as to prevent light from entering from the outside, it is necessary to perform white adjustment in a conventional dark room. Thus, the white adjustment operation can be easily performed. In this case, since the light shielding member 6 is provided integrally with the emission member 5, it is possible to prevent light from entering from the outside simply by mounting the emission member 5 on the lens hood 10 of the CCD camera. Can be shielded from light.

  Further, since the emitting member 5 is provided with a positioning portion (a step portion 6b of the light shielding member 6) for positioning the emitting member 5 so as to be arranged at a predetermined position with respect to the CCD camera 7, The objective lens 9 of the CCD camera 7 and the exit end 2b of each optical fiber 2 provided on the exit member 5 can be positioned so as to face, for example, directly, and the objective lens 9 of the CCD camera 7 and the exit end 2b of each optical fiber 2 can be positioned. The distance between the optical fiber 2 and the CCD camera 7 can be easily opposed to the CCD camera 7 at a predetermined position.

  As mentioned above, although one Embodiment of the white adjustment apparatus of the LED backlight which concerns on this invention was described, this invention is not limited to such embodiment at all, In the range which does not deviate from the summary of this invention, it is various aspects. Of course, it can be implemented. For example, the CCD camera 7 described above has a color CCD image sensor 8, but a rotating plate having a plurality of color filters (for example, R, G, B) is arranged in front of the monochrome CCD image sensor. A CCD camera configured to rotate the rotating plate, select each color filter, and sequentially capture images may be used, and is not limited to the above-described embodiment.

1: White adjustment device 2: Optical fiber 3: Incident member 3a: Incident surface 4: Light shielding member 4a: Front end portion 4b: Step portion 5: Emitting member 5a: Outgoing surface 6: Light shielding member 6a: Front end portion 6b: Step portion 7: CCD camera 8: Color CCD image sensor 9: Objective lens 10: Lens hood 11: Adjustment means 12: Adjustment unit 13: Memory 20: LED backlight 20a: Light emitting surface 21: Chassis 21a: Bottom surface 22: Light source 22R: Red LED 22G: Green LED 22B: Blue LED 23: Light diffusion plate 24: LED lighting circuit 25: LED drive circuit 26: Memory

Claims (15)

  A white adjustment device for an LED backlight, in which a plurality of light sources composed of a plurality of LEDs are arranged on the same plane, and irradiates white light generated by the colored light of each LED of the light source from the back side of the display panel. And a plurality of optical fibers on which white light from the light source is incident on one end so as to face each of the light sources on a one-to-one basis, and imaging means for imaging light emitted from the other end of the plurality of optical fibers And adjusting means for adjusting the luminance and / or chromaticity to be uniform within the light emitting surface of the LED backlight based on the two-dimensional image obtained by the imaging means. LED backlight white adjustment device.   2. The LED backlight according to claim 1, wherein one end of each of the plurality of optical fibers is inserted and fixed to a flat plate-shaped incident member disposed to face a light emitting surface of the LED backlight. Light white adjustment device   The white adjustment device for an LED backlight according to claim 2, wherein an antireflection treatment is applied to an incident surface of the incident member facing the light emitting surface of the LED backlight.   The white adjustment device for an LED backlight according to claim 3, wherein the antireflection treatment applied to the incident surface of the incident member is a black matte coating.   The light shielding member which shields light so that light may not enter from the exterior is provided in the outer periphery between the said incident member and the said LED backlight which are mutually opposingly arranged, The light shielding member is provided. The white adjustment apparatus of the LED backlight as described in any one.   6. The white color adjustment device for an LED backlight according to claim 5, wherein the light shielding member is provided integrally with the incident member.   The positioning member for positioning the incident member so that the incident member is disposed at a predetermined position with respect to the light emitting surface of the LED backlight. The white color adjustment apparatus of the LED backlight as described in any one of these.   The white position adjustment device for an LED backlight according to claim 7, wherein the positioning portion is provided on the light shielding member.   9. The other end of the plurality of optical fibers is inserted and fixed to a flat plate-shaped emission member disposed to face the imaging unit. The LED backlight white color adjusting device as described.   The white color adjustment device for an LED backlight according to claim 9, wherein an antireflection treatment is performed on an emission surface of the emission member facing the imaging unit.   The white adjustment device for an LED backlight according to claim 10, wherein the antireflection treatment applied to the emission surface of the emission member is a black matte coating.   The light shielding member for shielding light so that light does not enter from the outside is provided on an outer periphery between the emission member and the imaging unit arranged to face each other. A white color adjusting device for an LED backlight according to claim 1.   The white color adjustment device for an LED backlight according to claim 12, wherein the light shielding member is provided integrally with the emitting member.   The positioning member for positioning the emitting member so that the emitting member is arranged at a predetermined position with respect to the imaging means is provided. Item 2. A white color adjusting device for an LED backlight according to the item.   The white position adjustment device for an LED backlight according to claim 14, wherein the positioning portion is provided on the light shielding member.

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