JP2010217217A - White color adjusting device of led backlight - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a white color adjusting device of an LED backlight capable of shortening the time required for adjusting white color of the LED backlight. <P>SOLUTION: This white color adjusting device of the LED backlight is constituted by arranging a plurality of light sources each composed of a plurality of LEDs on the same plane to apply white color light produced by the light emitted by each LED in the light sources from a rear surface side of a display panel. This device has light receiving plates arranged substantially in parallel by opposing to a light emitting face of the LED backlight, optical sensors for receiving light from the light sources, and an adjusting means for adjusting white color to let luminance and/or chromaticity uniform within the light emitting face of the LED backlight based on the values detected by the optical sensors. A plurality of optical sensors are arranged on light receiving faces of the light receiving plates to oppose each light source in a one-to-one manner. <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.

  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 an imaging unit 31 and an adjusting unit 32. The imaging means 31 is a so-called two-dimensional chromaticity luminance meter, which is tristimulus values of red, green and blue (three basic stimuli necessary for equalizing the color stimulus of the sample in the three-color color system) A red filter 33R, a green filter 33G, and a blue filter 33B, which are optical filters having spectral transmission characteristics, and a monochrome CCD camera 34 capable of taking a two-dimensional image.

  In this case, these three color filters 33R, 33G, and 33B are attached to the rotating plate 35, and during the measurement, the filters 33R, 33G, and 33B are sequentially switched, and the light emitting surface 20a of the LED backlight 20 is changed by the monochrome CCD camera 34. By imaging, a two-dimensional tristimulus value image (two-dimensional image) can be obtained. Although not shown, a plurality of neutral density filters (ND filters) having a transmittance of, for example, 100% to 1.5% are usually provided between the rotary plate 35 and the monochrome CCD camera 34. ) Is mounted with the same structure as the rotating plate 35, and a necessary neutral density filter can be inserted in the optical path according to the intensity of the light incident on the monochrome CCD camera 34. Yes.

  Further, the adjusting unit 32 adjusts and resets the emission times of the red LED 22R, the green LED 22G, and the blue LED 22B included in each light source 22 based on the luminance and chromaticity obtained from the two-dimensional image captured by the imaging unit 31. Execute the process. 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, in the white adjustment device 30 using such an imaging unit 31, the three color filters 33R, 33G, and 33B are sequentially switched to individually detect light from each light source 22 provided in the LED backlight 20. Therefore, there is a problem that it takes time to image, and as a result, the time required for white adjustment of the LED backlight 20 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, a light receiving plate disposed substantially parallel to the light emitting surface of the LED backlight, a light sensor that receives light from the light source, and a detection value of the light sensor And adjusting means for adjusting the luminance and / or chromaticity to be uniform within the light emitting surface of the LED backlight, and the light sensor includes the light sources on the light receiving surface of the light receiving plate. The gist of the present invention is that a plurality are arranged so as to face each other one to one.

  According to the white color adjustment device for an LED backlight having such a configuration, a light receiving device in which a plurality of light sources composed of LEDs are arranged substantially parallel to the light emitting surface of the LED backlight arranged on the same plane. On the light receiving surface of the plate, a plurality of optical sensors that receive light from the light source are disposed so as to face each light source in a one-to-one relationship. The light from each light source can be easily detected in a lump by simply disposing them facing each other. 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 the optical sensor has a configuration composed of a plurality of photodiodes with color filters, for example, a commercially available optical sensor composed of a plurality of photodiodes with color filters can be used at a low cost. Can be configured. In addition, when such an optical sensor comprising a plurality of photodiodes with color filters is used, the time required for light detection can be shortened as compared with a CC image sensor provided in a conventional CCD camera.

  Further, if a light shielding member that shields light from entering from the outside is provided on the outer periphery between the light receiving plate and the LED backlight arranged to face each other, a conventional dark room is provided. This eliminates the need for white adjustment and makes it possible to easily perform white adjustment.

  Furthermore, if the light-shielding member is provided integrally with the light-receiving plate, the light-receiving plate can be simply shielded from entering from the outside simply by placing the light-receiving plate facing the LED backlight. .

  If the light receiving plate is provided with a positioning portion for positioning the light receiving surface of the light receiving plate at a predetermined position with respect to the light emitting surface of the LED backlight, Each light source of the light and each light sensor of the light receiving plate can be positioned, for example, one-on-one so as to face each other, and the distance between each light source and each light sensor can be made constant and reproduced. It is possible to arrange each optical sensor at a predetermined position with respect to each light source easily and efficiently. Further, if the positioning portion is provided in the light shielding member, the light receiving surface of the light receiving plate is positioned so as to be disposed at a predetermined position with respect to the light emitting surface of the LED backlight, and It is possible to block light from entering from between the light receiving plate and the LED backlight arranged opposite to each other.

  Furthermore, if the light receiving surface of the light receiving plate is subjected to an antireflection treatment, generation of stray light due to reflection of light from each light source of the LED backlight on the light receiving surface of the light receiving plate is suppressed. Therefore, it is possible to improve the detection accuracy by the optical sensors arranged to face each light source in a one-to-one relationship while eliminating the influence of such stray light. In this case, if the antireflection treatment applied to the light receiving surface of the light receiving plate is configured to have a black matte coating, the antireflection treatment can be easily applied to the light receiving surface of the light receiving plate.

  According to the LED backlight white color adjusting device according to the present invention, the light receiving surface of the light receiving plate disposed substantially parallel to the light emitting surface of the LED backlight has a one-to-one correspondence with each light source of the LED backlight. By simply arranging a light receiving plate having a plurality of photosensors facing each other so as to face the light emitting surface of the LED backlight, it is possible to easily detect the light from each light source in a lump. The time required for white adjustment of the backlight can be shortened compared to 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, the memory 26 includes a RAM (Random Access Memory) that can rewrite the LED control data. The memory 26 also includes a ROM (Read Only Memory) and an EEPROM (Electrically Erasable and Programmable Read Only Memory) that can write and save LED control data when adjustment by the white adjustment device 1 described later is completed. May be.

  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.

  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 is output from a plurality of photosensors 2, a light receiving plate 6 in which these photosensors 2 are arranged vertically and horizontally, and each photosensor 2. And an adjustment unit 9 that writes newly created LED control data based on the detected light value to a memory 26 included in the LED lighting circuit 24 of the LED backlight 20.

  The optical sensor 2 is a set of optical sensors including a photodiode with a red filter, a photodiode with a blue filter, and a photodiode with a blue filter. In this case, the optical sensor 2 includes three photodiodes 3, 4, and 5, and selectively receives red, green, and blue wavelength light on each light receiving surface side of the three photodiodes 3, 4, and 5. A red filter 3r, a green filter 4g, and a blue filter 5b that transmit (spectral transmission) are disposed.

  Accordingly, the white light generated by mixing the colored light of the LEDs 22R, 22G, and 22B of the light source 22 included in the LED backlight 20 passes through the color filters 3r, 4g, and 5b, so that each wavelength of red, blue, and green When separated into light having components and incident on each of the photodiodes 3, 4, and 5, the light is converted into light intensity (tristimulus values) having red, green, and blue wavelength components and detected collectively. It has become so.

  The color filters 3r, 4g, and 5b included in the optical sensor 2 have three types of spectral transmission characteristics that approximate the color matching function (CIE 1931 RGB color system) defined by the International Commission on Illumination (CIE). Applicable to R, G, B filters, and three types of X, Y, Z filters with spectral transmission characteristics that approximate the color matching function (CIE1931XYZ color system) defined by the International Commission on Illumination (CIE) Is possible.

  The light receiving plate 6 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 light receiving surface 6a is opposed to the light emitting surface 20a of the LED backlight 20. It arrange | positions so that it may become substantially parallel.

  In this case, the same number of light sensors 2 as the number of light sources 22 provided in the LED backlight 20 are arranged vertically and horizontally so as to be even on the light receiving surface 6a of the light receiving plate 6, and as shown in the drawing, the light receiving plate 6 Are arranged so as to face the light emitting surface 2a of the LED backlight 20, the light sources 22 and the photosensors 2 are arranged to face each other so as to face one on one.

  Further, the light receiving surface 6a of the light receiving plate 6 is subjected to antireflection treatment by black matte coating or the like. By performing the antireflection treatment on the light receiving surface 6a in this way, generation of stray light due to light from each light source 22 of the LED backlight 20 being reflected by the light receiving surface 6a is suppressed. Thus, the detection accuracy by the optical sensors 2 arranged to face the light sources 22 on a one-to-one basis can be improved.

  Further, a light-shielding member 7 having a hood shape that prevents light from entering from the outside is provided on the outer periphery between the light receiving plate 6 and the LE backlight 20 that are opposed to each other for white adjustment of the LED backlight 20. Is provided. In this case, the light shielding member 7 is attached and fixed so as to be integrated with the light receiving plate 6, and when the light receiving plate 6 is disposed to face the LED backlight 20, the front end portion 7 a of the light shielding member 7 becomes the LED backlight. It fits on the outer peripheral surface of 20 chassis 21.

  By providing the light shielding member 7 in this manner, no light enters from the outside between the LED backlight 20 and the light receiving plate 6, 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 adjusted. Adjustment work can be performed.

  A step 7 b is formed at the front end 7 a of the light shielding member 7, and this step 7 b comes into contact with the chassis 21 of the LED backlight 20. Therefore, when the light receiving plate 6 integrally provided with the light blocking member 7 is attached to the LED backlight 20, the light receiving surface of the light receiving plate 6 is made to the light emitting surface 20a of the LED backlight 20 by the step 7b. 6a is positioned at a predetermined position.

  By providing the positioning portion (step portion 7b) on the light receiving plate 6 in this way, each light source 22 of the LED backlight 20 and each photosensor 2 of the light receiving plate 6 are positioned so as to be directly opposite each other. The distance between each light source 22 and each light sensor 2 can also be made constant, and each light sensor 2 can be disposed opposite to each light source 22 at a predetermined position easily with good reproducibility. ing.

  In addition, it is preferable that the inner surface of the light shielding member 7 is also subjected to an antireflection treatment by black matte coating or the like. Also in this case, since the generation of stray light due to the light from each light source 22 of the LED backlight 20 being reflected by the inner surface of the light shielding member 7 is suppressed, the influence of such stray light is eliminated and each light source 22 is eliminated. It is possible to improve the light detection accuracy by the respective photosensors 2 arranged to face each other one to one.

  From each of the photodiodes 3, 4, and 5 included in each photosensor 2 disposed on the light receiving plate 6, a current indicating the intensity of light having each wavelength component of red, green, and blue is received. Is output. The current output from each of the photodiodes 3, 4, 5 is converted into a voltage by an I / V conversion circuit (not shown), and this voltage (analog value) is converted into a digital value by the A / D conversion circuit 8. The light detection value for each of the photodiodes 3, 4, 5 is output to the adjusting means 9.

  The adjustment means 9 is configured by an operation unit such as a PC (Personal Computer), a monitor, and a keyboard, for example, and includes an adjustment unit 10 and a memory 11. The adjusting means 9 is configured so that each LED 22R of each light source 22 has a light detection value (tristimulus value) output from each light sensor 2 within a setting range in which target luminance and chromaticity can be obtained. , 22G, and 22B, a process of newly creating LED control data is executed.

  Specifically, the adjusting unit 10 included in the adjusting unit 9 compares the light detection value output from each light sensor 2 with the light sensor reference value stored in the memory 11, and shifts to 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. In this case, the memory 11 includes a RAM (Random Access Memory). Note that the memory 11 may include a ROM (Read Only Memory) and an EEPROM (Electrically Erasable and Programmable Read Only Memory) in which the above-described optical sensor reference values are stored.

  For example, in the case where white light due to lighting of a certain light source 22 is reddish, that is, when the amount of colored light of the red LED 22R is larger than usual, the optical sensor arranged to face the light source 2 on a one-to-one basis. Since the light detection value of the photodiode 3 with the red filter 3r included in 2 is detected to be larger than usual, the adjustment unit 10 outputs the PWM output to the red LED 22R in order to reduce the amount of the colored light of the red LED 22R. The adjustment LED control data in which the on-duty ratio D of the signal is lowered is created, and a process of writing this in the memory 26 of the LED lighting circuit 24 is executed. Therefore, the adjustment unit 9 repeatedly performs such adjustment until the luminance and chromaticity of white light emitted from each light source 22 of the LED backlight 20 become uniform in the light emitting surface 20a.

  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 9.

  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 the light detection value detected by the photodiode 3 provided with the red filter 3r of each photosensor 2 that receives the light is detected. Then, it is stored in the memory 11 of the adjusting means 9 (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 a single color, and the light detection value detected by the photodiode 4 provided with the green filter 4g of each light sensor 2 that receives the light is detected by the adjusting means 9 Save in the memory 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 a single color, and the detection value detected by the photodiode 5 provided with the blue filter 5b of each photosensor 2 that receives this light is stored in the memory of the adjusting means 9 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 11 of the adjusting unit 9, and the adjusting unit 9 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, the light detection values detected by the photodiodes 3, 4, 5 of each photosensor 2 stored in the memory 11 of the adjusting means 9 in steps S 1 to S 3 and the photosensor reference stored in the memory 11. When these values are misaligned with each other, temporary adjustment LED control data (temporary adjustment on-duty ratio D data) corresponding to the misalignment amount is created, and this is generated by the LED lighting circuit 24. The initial LED control data (initial on-duty ratio D data) stored in the memory 26 is rewritten and stored (step S4).

  Then, the LEDs 22R, 22G, and 22B included in the light sources 22 of the LED backlight 20 are all made to emit light, and the light detection values detected by the photodiodes 3, 4, and 5 included in the light sensors 2 are adjusted. The data is stored in the memory 11 of the means 9 (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. Has been generated.

  Next, a setting range in which the target luminance and chromaticity stored in the memory 11 are obtained from the light detection values output from the respective optical sensors 2 that have received the white light from the respective light sources 22 in this manner. LED control data for driving the LEDs 22R, 22G, and 22B included in the light sources 22 is created so that the values are within the range. That is, the photodetection value of each photosensor 2 and the photosensor reference value stored in the memory 11 are compared (spec determination) (step S6), and when these values are shifted (step S6). 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 (stored in the memory 26 of the LED lighting circuit 24). Temporary adjustment on-duty ratio D data) is rewritten and stored (step S7).

  Step S5, step S6 (No), and step S7, which are the main adjustments, are performed by setting the light detection values output from the respective optical sensors 2 to obtain target luminance and chromaticity stored in the memory 11. It repeats until it becomes the value in (step S6 (Yes)). If the value is within the set range (step S6 (Yes)), the adjustment is terminated.

  According to the LED backlight white color adjusting device 1 described above, the light sources 22 composed of the LEDs 22R, 22G, and 22B are substantially parallel to and opposed to the light emitting surface 20a of the LED backlight 20 provided on the same plane. On the light receiving surface 6a of the light receiving plate 6 to be disposed, a plurality of optical sensors 2 that receive light from the light sources 22 are disposed so as to face the respective light sources 22 on a one-to-one basis. By simply arranging the light receiving plate 6 so as to face the light emitting surface 20a of the LED backlight 20, it is possible to easily detect the light from each light source 22 in a lump. 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 optical sensor 2 is composed of photodiodes 3, 4, and 5 with color filters, white adjustment can be made at low cost by using, for example, a commercially available optical sensor that includes a plurality of photodiodes with color filters. The apparatus 1 can be configured. In addition, when such an optical sensor comprising a plurality of photodiodes with color filters is used, the time required for light detection can be shortened as compared with a CC image sensor provided in a conventional CCD camera.

  In addition, since a light shielding member 7 is provided on the outer periphery between the light receiving plate 6 and the LED backlight 20 disposed so as to face each other so that light does not enter from the outside, it is white in a conventional dark room. There is no need to make adjustments, and it is possible to easily perform white adjustment work. Furthermore, since the light shielding member 7 is provided integrally with the light receiving plate 6, it is possible to simply shield the light from entering from the outside simply by placing the light receiving plate 6 opposite to the LED backlight 20. .

  The light receiving plate 6 is positioned so that the light receiving surface 6a of the light receiving plate 6 is disposed at a predetermined position with respect to the light emitting surface 20a of the LED backlight 20 (step 7b of the light shielding member 7). Therefore, each light source 22 of the LED backlight 20 and each light sensor 2 of the light receiving plate 6 can be positioned so as to be, for example, one-on-one, and each light source 22 and each light sensor 2 are The distance between them can also be made constant, and each optical sensor 2 can be opposed to each light source 22 at a predetermined position easily with good reproducibility.

  Further, since the light receiving surface 6a of the light receiving plate 6 is subjected to an antireflection treatment, generation of stray light due to reflection of light from each light source 22 of the LED backlight 20 by the light receiving surface 6a of the light receiving plate 6 is suppressed. Thus, it is possible to improve the detection accuracy by the respective optical sensors 2 arranged to face each light source 22 on a one-to-one basis by eliminating the influence of such stray light. In this case, as such an antireflection treatment for the light receiving surface 6a of the light receiving plate 6, if the light receiving surface 6a is configured to have a black matte coating, the light receiving surface of the light receiving plate can be simply subjected to the antireflection treatment. .

  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, an example is shown in which a plurality of photodiodes with color filters are applied as the configuration of the photosensor, but phototransistors with color filters may be applied, and the present invention is not limited to the above-described embodiment.

1: White adjustment device 2: Photosensor 3: Photodiode 3r: Red filter 4: Photodiode 4g: Green filter 5: Photodiode 5b: Blue filter 6: Light receiving plate 6a: Light receiving surface 7: Light blocking member 7a: Front end 7b : Step part 8: A / D conversion circuit 9: Adjustment means 10: Adjustment part 11: Memory 20: LED backlight 20a: Light emission 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 (8)

  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. A light receiving plate disposed substantially parallel to the light emitting surface of the LED backlight, a light sensor that receives light from the light source, and luminance and / or chromaticity based on a detection value of the light sensor. Adjusting means for adjusting the light emission surface to be uniform within the light emitting surface of the LED backlight, and a plurality of the light sensors are arranged on the light receiving surface of the light receiving plate so as to face the light sources on a one-to-one basis. A white color adjusting device for an LED backlight, which is provided.   The white light adjustment device for an LED backlight according to claim 1, wherein the photosensor includes a plurality of photodiodes with color filters.   The light-shielding member which light-shields so that light may not enter from the exterior is provided in the outer periphery between the said light-receiving plate and the said LED backlight which are mutually opposingly arranged, The Claim 1 or 2 characterized by the above-mentioned. LED backlight white adjustment device.   The white light adjusting device for an LED backlight according to claim 3, wherein the light shielding member is provided integrally with the light receiving plate.   The light receiving plate is provided with a positioning portion for positioning so that a light receiving surface of the light receiving plate is disposed at a predetermined position with respect to a light emitting surface of the LED backlight. The white color adjustment device for an LED backlight according to any one of 4.   The white color adjusting device for an LED backlight according to claim 5, wherein the positioning portion is provided on the light shielding member.   The white light adjusting device for an LED backlight according to any one of claims 1 to 6, wherein the light receiving surface of the light receiving plate is subjected to an antireflection treatment.   The white adjustment device for an LED backlight according to claim 7, wherein the antireflection treatment applied to the light receiving surface of the light receiving plate is a black matte coating.

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