JP2009020206A - Rear projection liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct color irregularity in a short period of time without carrying out complicated measurement or operation in a portion where the color irregularity occurs. <P>SOLUTION: A three-panel projection display device such as liquid crystal display device is disclosed, which can partially correct color irregularity in a displayed image. A portion of the display screen where correction for color irregularity is required is located and designated by a digitizer mounted on the display; and the color irregularity can be canceled while visually checking the display screen by setting a correction value based on a correction value indicator simultaneously displayed with the location designation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rear projection type liquid crystal display device integrated with a coordinate input means function for generating a color image by synthesizing a single color image respectively emitted from a plurality of liquid crystal panels functioning as a light valve by an optical system and projecting it on a screen. (Liquid Crystal Projector) and the like.

  In a liquid crystal projector, a single color image of R, G, and B transmitted through three liquid crystal panels is synthesized to generate a color image and projected onto a screen. However, the characteristics of these three liquid crystal panels vary. Further, the intensity of light incident on each liquid crystal panel also varies due to variations in the transmittance of dichroic mirrors for separating R, G, and B, which are components of the liquid crystal panel, and variations in the color temperature of the light source lamp. Further, the ambient temperature of the liquid crystal panel is different in each part, and the transmittance of each part of the liquid crystal varies, so that the light transmitted through the liquid crystal panel is not easily uniform in the plane.

  For the reasons described above, unique color unevenness occurs in the image projected by the liquid crystal projector. In order to eliminate this color unevenness, the chromaticity at some points on the screen is measured by a measuring device, and correction is made to the R, G, B signals of each pixel by the difference from the reference value. It has been known. A specific example will be described below.

  For example, a 50% white signal is supplied to the liquid crystal projector, and the screen at that time is, for example, divided into 20 parts horizontally and 15 parts vertically as shown in FIG. Then, the chromaticity of the point where the dividing line intersects with each other and the point where the dividing line intersects each side is measured (in this case, the measurement points are 21 × 16 = 336 locations).

  Next, the difference from the reference value of the chromaticity of each point is obtained, and the correction circuit adds or subtracts the obtained difference to the digitized R, G, B signal for each measurement point, Make the chromaticity of the point close to the reference value. Note that linear interpolation is performed between the corrected points.

  In the conventional color unevenness correction method described above, since linear interpolation is performed, it is necessary to increase the number of measurement points in order to increase the correction accuracy. In addition, a complicated color unevenness correction circuit for performing addition / subtraction and interpolation calculation on the R, G, and B signals must be separately installed in the liquid crystal projector. Further, if the number of measurement points is increased, the time required for correcting the color unevenness becomes longer, which becomes an obstacle when mass-producing liquid crystal projectors. It also becomes an obstacle in aging and accompanying replacement maintenance (serviceability) of parts such as lamps.

  In view of the above-described problems, an object of the present invention is to make it possible to correct color unevenness in a short time without performing complicated measurement or operation on a portion where color unevenness occurs.

The rear projection type liquid crystal display device of the present invention is a rear projection type liquid crystal display device that synthesizes monochromatic images respectively emitted from a plurality of liquid crystal light valves by an optical system, generates a color image and projects it on a screen, Coordinate input means for designating a reference position for color unevenness of the image synthesized by the optical system and a correction position for the color unevenness, and a correction value based on the reference position and the correction position designated by the coordinate input means. It is characterized in that color unevenness is corrected by calculation.
Further, another feature of the rear projection type liquid crystal display device of the present invention is that a rear surface that generates a color image by projecting it on a screen by synthesizing single color images respectively emitted from a plurality of liquid crystal light valves by an optical system. The projection-type liquid crystal display device includes color unevenness correcting means for correcting color unevenness of a displayed image, and the color unevenness correcting means includes division means for attenuating an input signal.
In addition, another feature of the rear projection type liquid crystal display device of the present invention is that a single color image emitted from each of a plurality of liquid crystal light valves is synthesized by an optical system, and a color image is generated and projected onto a screen. A projection-type liquid crystal display device, comprising color unevenness correcting means for correcting color unevenness of a displayed image, wherein the color unevenness correcting means includes a dividing means for attenuating an input signal and a degamma located after the dividing means. And a correcting means.

  According to the present invention, the correction value based on the reference position and the correction position of the specified color unevenness is calculated and the color unevenness correction is performed, so that the portion where the color unevenness occurs is subjected to complicated measurement and operation. Therefore, the color unevenness can be corrected in a short time.

(First embodiment)
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration example of a rear projection type liquid crystal display device of the present embodiment.
In FIG. 1, reference numeral 25 denotes a rear projection type liquid crystal display device (hereinafter referred to as a liquid crystal projector).

  The liquid crystal projector 25 includes a signal input unit 1, first to third A / D converters 2 to 4, a digital signal processing unit 5, an image quality improvement processing unit 6, and first to third D / A converters 7 to 7. 9, first to third drive circuits 10 to 12, and first to third liquid crystal panels 13 to 15. In addition, the optical system 16 that synthesizes and projects images from the first to third liquid crystal panels (liquid crystal light valves) 13 to 15, the screen 17, the operation pen 18, the coordinate detection sensor 19, and the coordinate detection unit 20 are included. Furthermore, a microcomputer (hereinafter referred to as a microcomputer) 21, a graphics generator 22, a signal generator 23, and a memory 24 are included. The output image of the personal computer or less (PC) 26 is supplied to the signal input unit 1 through the interface 28.

  Further, data such as drawing from the coordinate input unit is supplied to the PC 26 by the interface 27 under the control of the microcomputer 21. Needless to say, a video signal from a video signal source such as a VCR (not shown) may be supplied to the signal input unit 1 instead of the PC 26.

  Hereinafter, the processing after the image signal from the PC 26 is input to the signal input unit 1 will be described in detail. The signal input unit 1 sends the video signal to the first to third A / D converters 2 to 4 as color signals s1, s2, and s3 corresponding to the R, G, and B signals, respectively. The digital signal processing unit 5 performs the first to third liquid crystal panels 13 to 15 on the digital color signals s1, s2, and s3 that are digitally converted by the first to third A / D converters 2 to 4, respectively. Various digital signal processing such as pixel conversion and enlargement / reduction to match the number of pixels is added. Then, a digital R signal s4, a G signal s5, and a B signal s6 are generated and sent to the image quality improvement processing unit 6.

  The image quality improvement processing unit 6 has a function of displaying a menu generated from the graphics generating unit 22. When the hue adjustment and the uneven color correction are performed using the signal generation unit 23, the digital signal processing unit 5 selects R, G, and B signals for adjustment generated by the signal generation unit 23 to select the image quality. It is sent to the improvement processing unit 6. However, when another signal generator is connected to the signal input unit 1 and an adjustment signal is supplied from the outside to correct the hue adjustment and color unevenness of the liquid crystal projector, the first to third A / Ds The signals from the converters 2 to 4 are subjected to pixel conversion, enlargement / reduction, and the like, and are supplied to the image quality improvement processing unit 6.

FIG. 2 is a block diagram illustrating a detailed configuration example of the image quality improvement processing unit 6 according to the present embodiment.
As shown in FIG. 2, the image quality improvement processing unit 6 includes first to third digital division circuits 64 to 66, and first to third digital degamma correction circuits 67 to 69 at the subsequent stage. , R, G, and B are processed for each digital color signal.

  The first to third digital division circuits 64-66 are supplied with R, G, B division signals S13, S14, S15 from the microcomputer 21 shown in FIG. Next, the digital degamma correction circuits 67 to 69 in the subsequent stage use the degamma curves suitable for the average characteristics of the first to third liquid crystal panels 13 to 15 to change the colors of the digital R signal s10, G signal s11, and B signal s12. Each signal is corrected and output to adjust the hue.

  In addition, the image quality improvement processing unit 6 performs digital input to the first to third digital degamma correction circuits 67 to 69 in the subsequent stage using the correction data (divided signals) S13, S14, and S15 described above to eliminate color unevenness. The gain of the image signals S7, S8, S9 is controlled. The R color signal S13 corrected by the image quality improvement processing unit 6 is sent to the first D / A converter 7, and the G color signal S14 is sent to the second D / A converter 8. The B color signal S15 is sent to the third D / A converter 9, where it is converted into an analog signal.

  The first to third drive circuits 10 to 12 change the levels of the R, G, and B color signals converted into analog signals by the first to third D / A converters 7 to 9 to the first to third. The level is adapted to the specifications of the liquid crystal panels 13-15. Then, appropriate processing such as line inversion is performed, and the resultant is supplied to the R, G, and B first to third liquid crystal panels 13 to 15.

  The first to third liquid crystal panels 13 to 15 function as a light valve by receiving light emitted from a light source (not shown) and allowing each pixel to selectively transmit light. The R, G, and B images obtained in this way are output to the optical system 16 composed of prisms, mirrors, lenses, etc., synthesized by the optical system 16, and projected onto the screen 17. In the present embodiment, the screen 17 is a rear projection type screen as a rear projection.

FIG. 4 is a diagram illustrating a detailed configuration example of the coordinate input unit according to the present embodiment.
As shown in FIG. 4, the coordinate input part is comprised in the periphery of the screen 17, and the two coordinate detection sensors 19 shown in FIG. 1 are provided. The coordinate detection sensor 19 includes infrared light emitting diodes L1 and L2, line sensors LS1 and LS2, and imaging lenses LENS1 and LENS2.

  The operation pen 18 for inputting coordinates is used to indicate coordinates (correction positions), and infrared rays are output from the coordinate detection sensor 19 in a fan shape parallel to the screen 17. And it reflects with the reflector provided in the peripheral part of the screen 17, and is detected by the line sensors LS1 and LS2 provided in the coordinate detection sensor 19.

  For example, when an arbitrary position D1 on the screen 17 is designated by the operation pen 18, the position of the operation pen 18 is output as position information of the line sensors LS1 and LS2, and the coordinate detection unit 20 uses the angles θ1 and θ2. Can be converted.

  Furthermore, the coordinate detection unit 20 can determine the position on the screen 17 where the operation pen 18 is pointed by calculating the angles θ1 and θ2, and outputs the coordinate value to the microcomputer 21. The coordinate value may be calculated by the microcomputer 21. The coordinate input function by the operation pen 18 is output to the PC 26 connected to the outside via the interface 27 of the microcomputer 21 and used as an image drawing (digitizer) function. In addition, the coordinate input function using the operation pen 18 is a substitute for the PC 26 mouse.

  On the other hand, the microcomputer 21 determines a gamma curve used for hue adjustment in the image quality improvement processing unit 6 and a division value for correcting color unevenness. The memory 24 stores a function for performing color unevenness, coefficient values of the function, combination information of a plurality of color unevenness correction formulas, and the like. The interface 27 is provided for the microcomputer 21 to communicate with the PC 26 and a measuring instrument (not shown) via a communication cable such as USB, RS232C or the like. This measuring instrument (not shown) receives the projection light emitted from the projection lens of the optical system 16 and displayed on the screen 17, and measures the x and y values on the xy chromaticity diagram representing the chromaticity of the projection light. Then, the measurement data is sent to the microcomputer 21 via the interface 27.

  The microcomputer 21 can also exchange data with the memory 24 and output correction data for correcting color unevenness to the image quality improvement processing unit 6. The signal generation unit 23 supplies a white signal for adjustment to the digital signal processing unit 5 by a control signal from the microcomputer 21 at the time of hue adjustment and color unevenness correction. This white signal can be adjusted for all gradations by changing its level.

Next, the basic operation of color unevenness correction according to this embodiment will be described below.
First, when the input image signal is 8 bits, it is output 10 bits to the first to third digital division circuits 64 to 66 of the image quality improvement processing unit 6. Then, the corrected image is input in 10 bits to the first to third digital degamma correction circuits 67 to 69 in the subsequent stage.

  In addition, the first to third digital division circuits 64 to 66 of the image quality improvement processing unit 6 perform division by supplying correction data (division signals) S13, S14, and S15 from the microcomputer 21 with, for example, 4 bits. . When the input signal value is 0, the output is 0 regardless of the division value.

  Next, a case where the input signal is at a level of 100% will be described. When the peripheral signal level is 70% at the maximum with respect to the central level due to the luminance unevenness, the first to third liquid crystal panels 13 will be used if the peripheral light quantity is caused by the characteristics of the light source or the projection optical system. The drive signals of -15 are always driven at a level of 100 percent. Therefore, it is necessary to attenuate the drive signal so that the brightness and color unevenness due to the unevenness of the projected brightness at the position of the display screen are the same as the projected light quantity of the projection panel in the part where the projected light quantity is large. is there.

  Further, even if the desired luminance level is 50% of the intermediate level, the central level is reduced by 70% with respect to the peripheral display level. In order to eliminate this unevenness, it is necessary to attenuate the driving signal level in the central portion to 70% in consideration of the uniformity of gradation of the entire screen. That is, in the first to third digital division circuits 64 to 66, it is necessary to attenuate the level by division based on correction data (division signals) S13, S14, and S15 from the microcomputer 21.

Next, a specific correction method will be described below. FIG. 3 is a diagram illustrating an example of the occurrence position of color unevenness and a correction waveform in the present embodiment.
In the present embodiment, as shown in FIG. 3, when the standard portion (reference position) as the color tone is in the vicinity of P (c, d), POINT 1 is designated by the user with the operation pen 18. As a result, coordinate data is output from the coordinate detection unit 20 to the microcomputer 21.

  Next, the correction point POINT 2 that is recognized as the most uneven color deviation on the screen is designated by the user with the operation pen 18. In response to the second coordinate input (designation of POINT2), the microcomputer 21 issues a command to the graphics generator 22 to generate a color unevenness correction indicator as shown in FIG. An uneven color correction indicator is displayed on the screen, and a user designates a color designation palette in which the color tone of the uneven color is attached to the indicator. For example, if the color unevenness is closer to red, a red palette is designated by the operation pen 18.

  Next, level adjustment is performed by a cursor attached to the indicator. The click is attenuated by one step for each click in the minus direction, and the click is repeated by the user until the color tone becomes the same as that of POINT 1 at the reference position. Further, when the target value is far away, for example, it is possible to perform detailed setting by roughly setting by moving the cursor or by inputting a numerical value as shown in FIG.

  In the rectangular zone S1 having the POINT1 and the POINT2 as diagonals, correction is performed by replacing the shift amounts in the X direction and the Y direction with functions. The microcomputer 21 performs an arithmetic operation using an exponential function, or a primary and quadratic function, or a combination thereof, and performs division by the first to third digital division circuits 64 to 66 of the image quality improvement processing unit 6 as a correction signal. The correction function is performed as a diagonal, for example. Further, in the case where an insufficiently corrected portion occurs in the square zone S1 of the POINT1 and POINT2, the correction is further performed in the same manner as described above by being designated as the POINT3 by the operation pen 18.

  As described above, the spatial distribution of color unevenness is attenuated with respect to the three primary colors having strong color intensity by designating the reference position and the color unevenness correction position by the coordinate input unit and inputting correction values. To correct color unevenness. As a result, color unevenness correction can be performed more easily and accurately without special equipment for maintenance or the like. In addition, the color unevenness of the image is attenuated with respect to the color having a high luminance by the division circuit to correct the color balance, so that almost the same color unevenness correction is performed from the low luminance portion to the high luminance portion without depending on the gradation level. It can be carried out.

(Other embodiments according to the present invention)
A program stored in a RAM or a ROM of a computer operates in each step of the above-described units constituting the rear projection type liquid crystal display device and the control method of the rear projection type liquid crystal display device in the embodiment of the present invention. Can be realized. This program and a computer-readable recording medium (storage medium) recording (storing) the program are included in the present invention.

  In addition, the present invention can be implemented as a system, apparatus, method, program, recording medium (storage medium), or the like, and can be applied to a system including a plurality of devices. It may also be applied to an apparatus consisting of a single device.

  Note that the present invention includes a case where a software program that realizes the functions of the above-described embodiments is supplied directly or remotely to a system or apparatus. This includes the case where the system or the computer of the apparatus is also achieved by reading and executing the supplied program code.

  Accordingly, since the functions of the present invention are implemented by computer, the program code installed in the computer also implements the present invention. In other words, the present invention includes a computer program itself for realizing the functional processing of the present invention.

  In that case, as long as it has the function of a program, it may be in the form of object code, a program executed by an interpreter, script data supplied to the OS, and the like.

  Examples of the recording medium (storage medium) for supplying the program include a flexible disk, a hard disk, an optical disk, and a magneto-optical disk. Further, there are MO, CD-ROM, CD-R, CD-RW, magnetic tape, nonvolatile memory card, ROM, DVD (DVD-ROM, DVD-R) and the like.

  As another program supply method, there is a method of connecting to a homepage on the Internet using a browser of a client computer. Further, the computer program itself of the present invention or a compressed file including an automatic installation function can be downloaded from the homepage by downloading it to a recording medium (storage medium) such as a hard disk.

  It can also be realized by dividing the program code constituting the program of the present invention into a plurality of files and downloading each file from a different homepage. That is, a WWW server that allows a plurality of users to download a program file for realizing the functional processing of the present invention on a computer is also included in the present invention.

  As another method, the program of the present invention is encrypted, stored in a recording medium such as a CD-ROM, distributed to users, and encrypted from a homepage via the Internet to users who have cleared predetermined conditions. Download the key information to be solved. It is also possible to execute the encrypted program by using the key information and install the program on a computer.

  Further, the functions of the above-described embodiments are realized by the computer executing the read program. Furthermore, based on the instructions of the program, an OS or the like running on the computer performs part or all of the actual processing, and the functions of the above-described embodiments can be realized by the processing.

  Furthermore, as another method, a program read from a recording medium (storage medium) is first written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Then, based on the instructions of the program, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are also realized by the processing.

It is a block diagram which shows the structural example of the rear projection type liquid crystal display device of embodiment of this invention. It is a block diagram which shows the detailed structural example of the image quality improvement process part of embodiment of this invention. It is a figure which shows an example of the generation | occurrence | production position of a color nonuniformity and the correction waveform in embodiment of this invention. It is a figure which shows the detailed structural example of the coordinate input part of embodiment of this invention. It is a figure which shows an example of the screen displayed on the indicator in embodiment of this invention. It is a figure which shows an example of the measurement point of the nonuniformity of a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Signal input part 2 1st A / D converter 3 2nd A / D converter 4 3rd A / D converter 5 Digital signal processing part 6 Image quality improvement processing part 7 1st D / A converter 8 Second D / A converter 9 Third D / A converter 10 First drive circuit 11 Second drive circuit 12 Third drive circuit 13 First liquid crystal panel 14 Second liquid crystal panel 15 3 liquid crystal panel 16 optical system 17 screen 18 operation pen 19 coordinate detection sensor 20 coordinate detection unit 21 microcomputer 22 graphics generation unit 23 signal generation unit 24 memory 25 liquid crystal projector

Claims (3)

A rear projection type liquid crystal display device that synthesizes a single color image emitted from each of a plurality of liquid crystal light valves by an optical system, generates a color image and projects it on a screen,
Coordinate input means for designating a reference position for color unevenness of the image synthesized by the optical system and a correction position for the color unevenness,
A rear projection type liquid crystal display device which performs color unevenness correction by calculating a correction value based on a reference position and a correction position designated by the coordinate input means. A rear projection type liquid crystal display device that synthesizes a single color image emitted from each of a plurality of liquid crystal light valves by an optical system, generates a color image and projects it on a screen,
Color unevenness correcting means for correcting the color unevenness of the displayed image is provided,
2. The rear projection type liquid crystal display device according to claim 1, wherein the color unevenness correcting means includes a dividing means for attenuating an input signal. A rear projection type liquid crystal display device that synthesizes a single color image emitted from each of a plurality of liquid crystal light valves by an optical system, generates a color image and projects it on a screen,
Color unevenness correcting means for correcting the color unevenness of the displayed image is provided,
The back-projection type liquid crystal display device, wherein the color unevenness correcting means comprises a dividing means for attenuating an input signal and a degamma correcting means positioned after the dividing means.

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