JP2009271461A - Display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain increase of the circuit scale in a display apparatus for amplifying an image of one frame included in an image signal to a plurality of frames and displaying the plurality of frames by time sharing. <P>SOLUTION: An apparatus includes: an image processing means for carrying out an image process each two or more frames of images based on a setting value stored by a memory means; a display means for displaying the images processed by the image processing means; and a control means for storing in the memory means the setting value corresponding to an image of a frame different from the frame image displayed by the display means out of the images of 2 or more frames. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display device, and includes, for example, a drive circuit that drives a liquid crystal panel for displaying an image and a DMD (Digital Micromirror Device) panel (a panel in which micromirrors that operate independently for each pixel are arranged). The present invention relates to a display device.

  2. Description of the Related Art Conventionally, a projector or the like is known as a display device incorporating a drive circuit that drives a liquid crystal panel or a DMD panel. Among these projectors, there are projectors that drive a liquid crystal panel with alternating current (double speed drive).

  The AC drive is a drive in which a drive voltage applied to the pixel electrode of the liquid crystal panel is alternately changed between a positive voltage and a negative voltage in a frame unit of a video signal with a certain voltage as a center (Vcom). The liquid crystal panel adjusts the degree of light transmission by applying a voltage to the encapsulated liquid crystal molecules and changing the alignment direction of the liquid crystal molecules. In some cases, the orientation of the film may be biased. Therefore, AC driving is performed by utilizing the property that the alignment direction of liquid crystal molecules can be adjusted regardless of whether a positive voltage or a negative voltage is applied to the transparent electrode of the liquid crystal panel. By doing so, the orientation of the liquid crystal molecules is not biased.

  Also, these projectors receive a video signal or the like input from the outside, form an image on the panel based on the video signal, supply the light supplied from the light source to the panel, and project the image to the outside ing. At this time, the liquid crystal projector that performs the AC driving described above records the input video signal once in the frame memory, and performs a positive voltage driving frame (positive frame) and a negative voltage driving frame (negative frame). Reading is performed once at a double speed. The positive frame is also called a positive frame and the negative frame is also called a negative frame.

  The image read in this way is then sent to a gamma correction circuit where gamma correction is performed in accordance with the characteristics of the panel and optical system. However, depending on the characteristics of the liquid crystal panel, the transmittance characteristics of the liquid crystal panel may not be the same when a positive voltage is applied and when a negative voltage is applied. For example, the concentration may differ between when a positive voltage is applied and when a negative voltage is applied. Therefore, the gamma correction circuit performs separate gamma correction for the positive frame and the negative frame, and corrects the gradation characteristics so that the positive frame and the negative frame have the same density on the liquid crystal panel. . As for other corrections, for example, unevenness correction, separate processing is performed when a positive frame is displayed and when a negative frame is displayed.

  Setting values for gamma correction in the gamma correction circuit and other setting values for correction are recorded in a register of the register setting circuit. That is, in the register setting circuit, different setting values must be prepared for each circuit when displaying a positive frame and when displaying a negative frame.

  Further, the CPU that rewrites the setting value recorded in the register transmits the setting value asynchronously with frame switching. Therefore, for example, prepare two registers for the main frame so that the setting value for the main frame is not rewritten while the image of the main frame is displayed. The value was rewritten. The influence on the display image is reduced by switching to use the previously rewritten register while it is determined by the frame identification signal that the negative frame image is displayed. The same applies to the negative frame.

  Some projectors use DMD panels. In a DMD panel projector, red, green, and blue light are supplied to the micromirrors in a time-sharing manner, and the ratio of reflecting each color component of the image to be displayed on the DMD panel is adjusted. An image is formed.

  These projectors receive a video signal or the like input from the outside, form an image on the panel based on the video signal, and supply the light supplied from the light source to the panel to project the image to the outside. . At this time, in the DMD projector, the input video signal is once recorded in the frame memory. For example, the red (R) frame, the green (G) frame, and the blue (B) frame are tripled. The data is read once at a speed. The R frame is an image of a red component of one frame recorded in the frame memory. Similarly, the G frame and the B frame are images of a green component and a blue component, respectively.

Similarly to the liquid crystal projector, the DMD projector also needs to perform separate processing on each of the R frame, G frame, and B frame images in order to cope with the characteristics of the optical system.
Japanese Patent Laid-Open No. 4-80714 JP-A-11-239359

  However, in the conventional liquid crystal projector, the first register that records the setting value currently used for each of the positive frame and the negative frame, and the second register that records the setting value to be set next. Was necessary. That is, for each frame, a register only for recording set values used for correcting the image for two frames is necessary, and the circuit scale has been increased. Similarly, since the DMD projector has R frames, G frames, and B frames, a register that only records setting values used for image correction for 6 frames is necessary, which increases the circuit scale. It was.

  The present invention has been made in view of such a problem, and an object thereof is to provide a display device capable of suppressing an increase in circuit scale.

  In order to solve such a problem, the display device of the present invention includes an input unit that acquires a video signal to be displayed, and an image of two or more frames from one frame image of the video signal acquired by the input unit. Generating means for generating; storage means for storing setting values corresponding to images of the respective frames of the two or more frames used for image processing of the images of the two or more frames generated by the generating means; Based on the setting value stored by the storage unit, an image processing unit that performs image processing on each of the images of two or more frames, a display unit that displays an image processed by the image processing unit, and two or more frames The setting value corresponding to an image of a frame different from the image of the frame displayed by the display unit is stored in the storage unit. Characterized by a control unit.

  According to the present invention, it is possible to save a register circuit for setting a correction value for each frame, so that an increase in circuit scale can be suppressed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In this embodiment, a liquid crystal projector having a built-in liquid crystal panel that performs AC driving will be described.

  FIG. 1 is a diagram showing the main configuration of the liquid crystal projector of this embodiment.

  Reference numeral 101 denotes a control unit for controlling each block of the projector. Reference numeral 102 denotes a data bus through which various signals such as control signals and video signals come and go. Reference numeral 103 denotes an operation unit that receives an operation from the user. A power supply unit 104 controls power supply to each block of the projector.

  An input unit 105 receives a video signal from a PC, a DVD player, a TV tuner, a memory card, or the like. 106 converts the number of pixels of the video signal input from the input unit in accordance with the number of pixels of the liquid crystal panel, which will be described later, and doubles the number of frames of the input video signal for AC driving of the liquid crystal panel. This is an image processing unit that performs correction suitable for image formation. The image processing unit 106 corrects the gamma characteristic of the input image or corrects the luminance unevenness generated by the optical system. The degree of correction is changed depending on, for example, the projection mode (movie mode, presentation mode, still image mode, etc.). At this time, the setting value for correction is set in the register in the image processing unit 106 by the control unit 101. For example, in the case of gamma correction, the gamma characteristic of the image can be changed by changing the correspondence relationship between the output level and the input level of the color lookup table.

  Reference numeral 107 forms an image on the liquid crystal panel in the liquid crystal unit 108 based on the video signal corrected by the image processing unit. For example, if the projector uses three liquid crystal panels, the liquid crystal panel is controlled for each of the three colors, and an image for each color is formed on the liquid crystal panel. In this case, light input from the light source 109 described later is separated into three colors, light of each color is supplied to the liquid crystal panel corresponding to each color, an optical image for each color is formed, and the optical image is again displayed. These are combined and output to the projection optical system 111 described later.

  Reference numeral 109 denotes a light source that emits light for projecting an image onto a screen (not shown). Reference numeral 110 denotes a light source control unit that controls the on / off operation of the light source 109 and the amount of light. A projection optical system 111 projects an optical image obtained by passing through the liquid crystal unit 108 onto a screen (not shown). Reference numeral 112 denotes an optical system control unit that controls the projection optical system 111 to adjust the zoom, focus, and the like of the projection optical system 111.

  Reference numeral 113 denotes a temperature detection unit arranged in the vicinity of the light source, which measures the temperature related to the light source 109 (performs temperature measurement) and transmits the result to the control unit 101. Reference numeral 114 denotes a timer that is operated by a battery (not shown), and performs a time measurement operation and transmits the result to the control unit 101. Reference numeral 115 denotes an optical sensor that measures (measures) the light reaching the projection optical system, and transmits the result to the control unit 101.

  The control unit 101 uses at least one of the data acquired from the temperature detection unit 113, the timer 114, and the optical sensor 115 to control the projector power supply unit 104, the liquid crystal drive unit 107, the light source control unit 109, and the like. Take control.

  Here, the operation of a normal projector will be described.

  The control unit 101 of the projector according to the present embodiment instructs the power supply unit 104 to supply power to each block when the operation unit 103 is instructed to turn on the power, and puts each block in a standby state. After the power is turned on, the control unit 101 instructs the light source control unit 110 to start light emission from the light source 109. Next, the control unit 101 instructs the optical system control unit 112 to adjust the projection optical system 111. The optical system control unit 112 acquires a distance from a screen (not shown) and automatically controls the projection optical system 111 to control zoom and focus. Further, the optical system control unit 112 may adjust the projection optical system 111 by the operation of the operation unit 103 by the user.

  In this way, the projection is ready. Next, the video signal input from the input unit 105 is converted into a resolution suitable for the liquid crystal unit 108 by the image processing unit 106, and gamma correction and luminance unevenness correction are applied. The video signal corrected by the image processing unit 106 is formed as an image on the liquid crystal unit 108 by the liquid crystal driving unit 107.

  Usually, in AC driving, a line inversion driving method is employed in which the polarity of an applied electric field is inverted for each line of array pixels and the polarity is switched at a predetermined cycle such as 60 hertz. In addition, a field inversion drive method is also used in which the polarity of the electric field applied to all of the array pixels is inverted at a predetermined period.

  In the present embodiment, when the voltage applied to the electrode on one side of the liquid crystal panel is a constant value Vcom, the voltage on the opposite side across the liquid crystal is adjusted in units of pixels. In this case, an AC voltage centered on Vcom is applied to the electrode side that adjusts the voltage in pixel units. An image formed when a positive voltage is applied to the electrode side that adjusts the voltage in pixel units with Vcom as a reference is called a positive frame image. Conversely, an image formed when a negative voltage is applied to the electrode side that adjusts the voltage in pixel units with Vcom as a reference is called a negative frame image.

Next, details of the image processing unit 106 will be described.
FIG. 2 is a diagram illustrating a detailed configuration of the image processing unit 106.
In FIG. 2, reference numeral 201 denotes a frame that receives a synchronization signal for synchronizing with a video signal, and generates a frame identification signal for identifying a positive frame and a negative frame when the liquid crystal panel performs AC driving. It is an identification signal generation unit. A frame identification signal is supplied to the control unit 101, the liquid crystal drive unit 107, and other circuits. In this embodiment, when the frame identification signal is H, it indicates that the positive polarity frame is displayed, and when the frame identification signal is L, it indicates that the negative polarity frame is displayed.

  A resolution conversion unit 202 converts the number of pixels of the video signal obtained by the input unit 105 according to the number of pixels of the liquid crystal panel. Reference numeral 203 denotes a double speed conversion unit that doubles the number of frames of the video signal whose number of pixels has been converted by the resolution conversion unit. The double speed conversion unit 203 once writes the video signal in the frame memory. Then, the image of one frame written in the frame memory is read twice at a speed twice the speed indicated by the synchronizing signal of the video signal. One of the frame images read out in this way is a positive frame image, and the other is a negative frame image. That is, the double speed conversion unit 203 generates a positive frame image and a negative frame image.

  A gamma correction unit 204 corrects the gamma characteristic of the image obtained by the double speed conversion unit 203. The gamma correction unit performs positive frame gamma correction on a positive frame image and negative frame gamma on a negative frame image. Make corrections. Therefore, for example, when the frame identification signal is H, the gamma correction unit 204 reads the setting value corresponding to the positive frame from the register circuit and corrects the gamma characteristic of the image of the positive frame.

  Reference numeral 205 denotes an unevenness correction unit that performs correction processing (hereinafter referred to as unevenness correction processing) on an image whose gamma characteristics have been corrected by the gamma correction unit 204 in order to cancel brightness and color unevenness due to an optical system or the like. Similar to the gamma correction unit 204, positive frame unevenness correction processing is performed on positive frame images, and negative frame unevenness correction processing is performed on negative frame images.

  The order of the correction processing by the gamma correction unit 204 and the correction processing by the unevenness correction unit 205 is not limited.

  A register circuit 206 stores a setting value for gamma correction and a setting value for unevenness correction. The register circuit includes a register 207 that records a setting value for a positive frame and a register 208 that records a setting value for a negative frame. The setting value for each frame recorded in the registers 207 and 208 in the register circuit 206 is updated by the control unit 101.

  In the present embodiment, the double speed conversion unit 203 doubles the number of frames of the original video signal and applies a positive voltage to display a positive frame and a negative frame to apply and display a negative voltage. A frame is being generated. The positive frame image and the negative frame image generated in this way are displayed on the liquid crystal panel in a time-sharing manner.

  Depending on the characteristics of the liquid crystal panel driven by alternating current, the transmittance characteristics of the liquid crystal panel may not be the same when a positive voltage is applied and when a negative voltage is applied. Then, for example, the concentration differs between when a positive voltage is applied and when a negative voltage is applied. Therefore, the gamma correction unit 204 needs to perform separate gamma correction for the positive frame and the negative frame, and to correct the gradation characteristics so that the positive frame and the negative frame have the same density on the liquid crystal panel. There is. In the unevenness correction unit 205, it is necessary to perform separate unevenness correction processing when the positive frame is displayed and when the negative frame is displayed.

  Therefore, in this embodiment, the setting value for the negative frame is recorded in the register 208 by the control unit 101 while the image of the positive frame is corrected and displayed. Then, while the negative frame image is displayed, the control unit 101 records the setting value for the positive frame in the register 207. For example, when the frame rate of the video is 30 fps, the time for correcting and converting each frame is about 1/60 second. Within this period, a setting value used for correcting an image of a frame having a polarity opposite to that of the currently displayed frame may be set in the register circuit 206. In this way, in this embodiment, it is not necessary to prepare two frame setting values for the positive frame, and similarly, it is not necessary to prepare two frame setting values for the negative frame. Therefore, an increase in circuit scale can be suppressed.

Operations of the image processing unit 106 and the control unit 101 of the present embodiment will be described with reference to FIG.
The video signal obtained by the input unit 105 is converted by the resolution conversion unit 202 in accordance with the number of pixels of the liquid crystal panel, and the frame rate is doubled by the double speed conversion unit 203. One of the doubled frame images is used as a positive frame image during AC driving, and the other is used as a negative frame image. Then, the positive frame image and the negative frame image are respectively sent to the gamma correction unit 204.

  Here, the operation of each block when a normal frame image is displayed will be described.

  In the gamma correction unit 204, whether the input image is a positive frame image or a negative frame image is whether the frame identification signal generated by the frame identification signal generation unit 201 is H or L. Determined by When it is determined that the input image is a positive frame image, gamma correction is performed using the set value for the positive frame recorded in the register 207 of the register setting circuit 206.

  Similarly, the unevenness correction unit 205 determines whether the input image is a positive frame image or a negative frame image depending on whether the frame identification signal is H or L. When it is determined that the input image is an image of a positive frame, the unevenness correction process is performed using the set value for the positive frame recorded in the register 207 of the register setting circuit 206.

  The correct frame image subjected to each correction process is sent to the liquid crystal drive unit 107, and the liquid crystal drive unit 107 displays the image on the liquid crystal unit 108 as a normal frame image.

  The setting value for each correction of the negative frame is changed when the correction and display of the positive frame are being performed. Therefore, when the control unit 101 determines that the frame identification signal is H, the control unit 101 records the negative frame correction setting value in the register 208 in the register circuit 206.

  Similarly, when a negative frame image is displayed, the gamma correction unit 204 and the unevenness correction unit 205 read the set value for correction from the register 208 in the register circuit 206 and perform correction processing. When the control unit 101 determines that the frame identification signal is L, the control unit 101 records the correction setting value for the positive frame in the register 207 in the register circuit 206.

FIG. 3 is a sequence diagram for explaining the register setting timing.
In FIG. 3, 301 indicates a video signal obtained by the input unit 105, and 302 indicates a synchronization signal of the video signal input to the frame identification signal generation unit 201. Reference numeral 303 denotes a video signal whose frame rate has been doubled by the double speed conversion unit 203. Reference numeral 304 denotes a frame identification signal generated by the frame identification signal generation unit 201. When the frame identification signal is H, correction processing and display for a positive frame image are performed, and when the frame identification signal is L, correction processing and display for a negative frame image are performed.

  Reference numeral 305 denotes a video signal supplied to the liquid crystal unit 108, and a video signal whose polarity is inverted when the frame identification signal is H or L is supplied. Reference numeral 306 denotes timing when the control unit 101 communicates with the register circuit 206. When the frame identification signal is H, the setting value for correcting the negative frame image is stored, so the storing operation is performed in the register 208. When the frame identification signal is L, the setting value for correcting the positive frame image is stored. Therefore, the storage operation is performed in the register 207.

Reference numeral 307 denotes a mode switching signal input to the control unit 101 by the operation unit 103.
For example, when a mode switching signal is input at a timing as indicated by 307, the control unit 101 stores a setting value for correction in the register circuit 206. For this purpose, the control unit 101 stores the set value in the next positive frame register 207 at the timing of 309, and then stores the set value in the negative frame register 208 at the timing of 310. Alternatively, when the rewritable register is rewritten immediately after the mode switching signal is input, the set value may be stored first in the negative frame register 208 at the timing 308.

  In this way, the projector using the liquid crystal panel that performs AC driving according to the present embodiment performs the correction and the set value for correcting the frame having a polarity opposite to that of the displayed frame. It becomes possible to suppress.

  In this embodiment, the projector has been described. However, any display device having a liquid crystal element can be applied to, for example, a liquid crystal television, a liquid crystal display, a digital camera, a portable game machine, and a mobile phone.

  In this embodiment, a DMD projector using a DMD panel will be described.

FIG. 4 is a block diagram of a DMD projector using the DMD panel of this embodiment.
Reference numeral 401 denotes a control unit for controlling each block of the projector. Reference numeral 402 denotes a data bus through which various signals such as control signals and video signals come and go. Reference numeral 403 denotes an operation unit that receives an operation from the user. Reference numeral 404 denotes a power supply unit that controls power supply to each block of the projector.

  Reference numeral 405 denotes an input unit that receives a video signal from a PC, a DVD player, a TV tuner, a memory card, or the like. 406 converts the number of pixels of the video signal input from the input unit according to the number of pixels of the DMD panel, which will be described later, and triples the frame of the input video signal to form an image on the DMD panel. An image processing unit that performs correction suitable for image formation by a panel. The image processing unit 406 corrects the gamma characteristic of the input image or corrects the luminance unevenness generated by the optical system. These corrections are changed depending on, for example, the projection mode (movie mode, presentation mode, still image mode, etc.). At this time, the correction value is set in a register in the image processing unit 406 by the control unit 401. Also, the frame rate of the video signal is, for example, 3 times when displaying with RGB light, but sometimes 6 times, and 6 times when displaying with RGBCMY light. Or it may be doubled. That is, it may be amplified into a plurality of color frames corresponding to a plurality of color lights.

  Reference numeral 407 forms an image on the DMD panel in the DMD unit 108 based on the video signal corrected by the image processing unit. In this case, an image for each color is formed on the DMD panel in a time division manner in accordance with the three colors of RGB light input in a time division manner from a light source 409, which will be described later. 411 is output.

  Reference numeral 409 denotes a light source that generates light of each color by transmitting an R filter, a G filter, and a B filter of a color wheel in order to supply RGB three-color light to the DMD panel in a time-sharing manner. Reference numeral 410 denotes a light source control unit that performs on / off operation of the light source 409, control of the light amount, and rotation control of the color wheel. The light source control unit 410 receives the frame identification signal from the image processing unit 406 and performs rotation control of the color wheel of the light source 409.

  Reference numeral 411 denotes a projection optical system for projecting an optical image formed by the DMD unit 408 onto a screen (not shown). An optical system control unit 412 controls the projection optical system 411 so as to adjust the zoom, focus, and the like of the projection optical system 411.

  Reference numeral 413 denotes a temperature detection unit disposed in the vicinity of the light source, which measures the temperature related to the light source 409 (performs temperature measurement) and transmits the result to the control unit 401. Reference numeral 414 denotes a timer that is operated by a battery (not shown), and performs a time measurement operation and transmits the result to the control unit 401. Reference numeral 415 denotes an optical sensor that measures (measures) light reaching the projection optical system, and transmits the result to the control unit 401.

  The control unit 401 uses the at least one of the data acquired from the temperature detection unit 413, the timer 414, and the optical sensor 415 to control the projector power supply unit 404, the liquid crystal drive unit 407, the light source control unit 409, and the like. Take control.

Here, the operation of a normal DMD projector will be described.
The control unit 401 of the projector according to the present embodiment instructs the power supply unit 404 to supply power to each block when the operation unit 403 is instructed to turn on the power, and puts each block in a standby state. After the power is turned on, the control unit 401 instructs the light source control unit 410 to start light emission from the light source 409. Next, the control unit 401 instructs the optical system control unit 412 to adjust the projection optical system 411. The optical system control unit 412 acquires a distance from a screen (not shown) and automatically controls the projection optical system 411 to control zoom and focus. Further, the optical system control unit 412 may adjust the projection optical system 411 by the operation of the operation unit 403 by the user.

  In this way, the projection is ready. Next, the video signal input from the input unit 405 is converted into a resolution suitable for the DMD unit 408 by the image processing unit 406, and gamma correction and correction for luminance unevenness are added. The video signal corrected by the image processing unit 406 is formed as an image in the DMD unit 408 by the DMD liquid crystal driving unit 407.

  Usually, in a projector using a DMD panel, the micromirrors on the DMD panel are controlled in accordance with light of three colors supplied in a time division manner by a light source 409. For example, when R light is incident on the DMD panel from the light source, the DMD driving unit 407 operates to control the micromirrors of the DMD panel according to the R component image. Similarly, when the G and B lights are incident on the DMD panel, the DMD driving unit 407 operates to control the micromirrors of the DMD panel according to the images of the G and B components.

Next, details of the image processing unit 406 will be described.
FIG. 5 is a diagram illustrating a detailed configuration of the image processing unit 406.
In FIG. 5, reference numeral 501 receives a synchronization signal for synchronizing with a video signal, and generates a frame identification signal for generating a frame identification signal for identifying an R frame, a G frame, and a B frame when driving a DMD panel. Part. A frame identification signal is supplied to the control unit 401, the DMD driving unit 407, the light source control unit 410, and other circuits. In this embodiment, when the frame identification signal is R, it indicates that the R frame is displayed, and when the frame identification signal is G or B, it indicates that the G or B frame is displayed. .

  A resolution conversion unit 502 converts the number of pixels of the video signal obtained by the input unit 405 according to the number of pixels of the DMD panel. Reference numeral 503 denotes a triple speed conversion unit that triples the number of frames of the video signal whose number of pixels has been converted by the resolution conversion unit, for example. The triple speed conversion unit 503 once writes the video signal in the frame memory. Then, the R component, G component, and B component of the image of one frame written in the frame memory are read once at a speed that is three times the frame rate of the video signal. The read R component image is an R frame image, the G component image is a G frame image, and the B component image is a B frame image.

  Reference numeral 504 denotes a gamma correction unit that corrects the gamma characteristic of the image obtained by the double speed conversion unit 503. The R frame image is subjected to gamma correction for the R frame, and the G and B frame images are G and B. Perform gamma correction for the frame. Therefore, for example, when the frame identification signal is R, the gamma correction unit 504 reads the setting value corresponding to the R frame from the register circuit and corrects the gamma characteristic of the R frame image.

Reference numeral 505 denotes an unevenness correction unit that performs correction processing (hereinafter referred to as unevenness correction processing) on an image whose gamma characteristics have been corrected by the gamma correction unit 504 in order to cancel brightness and color unevenness due to the optical system or the like. Similar to the gamma correction unit 504, R frame unevenness correction processing is performed on the R frame image, and G and B frame unevenness correction processing is performed on the G and B frame images.
The order of the correction processing by the gamma correction unit 504 and the correction processing by the unevenness correction unit 505 are not limited.

  A register circuit 506 records a setting value for gamma correction and a setting value for unevenness correction. The register circuit includes a register 507 that records setting values for the R frame, a register 508 that records setting values for the G frame, and a register 509 that records setting values for the B frame. The setting value for each frame recorded in the registers 507, 508, and 509 in the register circuit 506 is updated by the control unit 401.

In this embodiment, the triple speed conversion unit 503 triples the frame rate of the original video signal, forms an image by reflecting the R light and forming the image by reflecting the R light and the G light. The G frame for generating the image and the B frame for forming the image by reflecting the B light are generated. The R frame image, the G frame image, and the B frame image generated in this way are supplied to the DMD panel in a time division manner.
Even in the DMD panel, it is necessary to perform different gamma correction processing and unevenness correction processing for each color.

  Therefore, in this embodiment, the setting value for the G and / or B frame is recorded in the register 508 and / or the register 509 by the control unit 101 while the image of the R frame is corrected and displayed. Then, while the G frame image is displayed, the control unit 101 records the setting values for the R and / or B frames in the register 507 and / or the register 509. For example, when the frame rate of the video is 30 fps, the time for correcting and converting each frame is about 1/90 seconds. Within this period, a setting value used for correcting an image of a frame having a color different from that of the currently displayed frame may be set in the register circuit 506. Alternatively, a setting value used for correcting an image of a frame having a color different from the currently displayed frame may be set in the register circuit 506 within about 2/90 seconds. In this way, in this embodiment, it is not necessary to prepare R frame setting values for two frames, and similarly, it is not necessary to prepare G and B frame setting values for two frames. . Therefore, an increase in circuit scale can be suppressed.

Operations of the image processing unit 406 and the control unit 401 according to the present exemplary embodiment will be described with reference to FIG.
The video signal obtained by the input unit 405 is converted by the resolution conversion unit 502 according to the number of pixels of the liquid crystal panel, and the frame rate is tripled by the triple speed conversion unit 503. One of the tripled frame images is used as an R frame image which is an R component image, one is a G frame image, and one is a B frame image. Then, the R frame image, the G frame image, and the B frame image are respectively sent to the gamma correction unit 504.

Here, the operation of each block when the R frame image is displayed will be described.
In the gamma correction unit 504, whether the input image is an R frame image, a G frame image, or a B frame image is determined by whether the frame identification signal generated by the frame identification signal generation unit 501 is R or G. It is determined whether it is B or B. If it is determined that the input image is an R frame image, the register setting circuit 506 performs gamma correction using the setting value for the R frame recorded in the register 507.

  Similarly, the unevenness correction unit 505 determines whether the input image is an R frame image, a G frame image, or a B frame image, whether the frame identification signal is R, G, or B. Determine by If it is determined that the input image is an R frame image, the register setting circuit 506 performs unevenness correction processing using the set value for the R frame recorded in the register 507.

  The R frame image subjected to each correction process is sent to the DMD driving unit 407, and the DMD driving unit 407 displays the image on the DMD unit 408 as an R frame image.

  The setting value for each correction of the G frame and / or the B frame is changed when the R frame is corrected and displayed. Therefore, when the control unit 401 determines that the frame identification signal is R, the control unit 401 records the correction setting value for the G frame and / or the B frame in the register 208 and / or the register 509 in the register circuit 506.

  Similarly, when the G frame image is displayed, the gamma correction unit 504 and the unevenness correction unit 505 read the set value for correction from the register 508 in the register circuit 506 and perform correction processing. When the control unit 401 determines that the frame identification signal is G, the control unit 401 records the correction setting value for the R frame and / or the B frame in the register 507 and / or the register 509 in the register circuit 506.

FIG. 6 is a sequence diagram for explaining the register setting timing.
In FIG. 6, 601 indicates a video signal obtained by the input unit 405, and 602 indicates a synchronization signal of the video signal input to the frame identification signal generation unit 501. Reference numeral 603 denotes a video signal whose frame rate has been tripled by the triple speed conversion unit 503. Reference numeral 604 denotes a frame identification signal generated by the frame identification signal generation unit 501. When the frame identification signal is R, correction processing and display of the R frame image are performed, and when G and B, correction processing and display of the G and B frame images are performed.

  Reference numeral 605 denotes timing when the control unit 401 communicates with the register circuit 506. When the frame identification signal is R, the setting value for correcting the image of the G frame and / or the B frame is recorded, so that the recording operation is performed in the register 208 and / or the register 209. At the time of G, since the setting value for correcting the image of the R frame and / or the B frame is recorded, the recording operation is performed in the register 207 and / or the register 209. At the time of B, since the setting value for correcting the image of the R frame and / or the G frame is recorded, the recording operation is performed in the register 207 and / or the register 208. In this embodiment, a setting value for correcting the image of the B frame is recorded during display of the R frame, and a setting value for correction of the R frame image is recorded during display of the G frame. During display, a set value for correcting the G frame image is recorded.

Reference numeral 606 denotes a mode switching signal input to the control unit 401 by the operation unit 403.
For example, when a mode switching signal is input at a timing as indicated by 606, the control unit 401 stores a setting value for correction in the register circuit 506. For this purpose, the control unit 401 stores the set value in the R frame register 507 at the timing 609. Thereafter, the setting value is stored in the G frame register 508 at the timing 610, and the setting value is stored in the B frame register 509 at the timing 611. That is, the base image is stored from the set value of the R frame so that the gamma characteristic and the like are changed from the same frame. In the case of a DMD projector that displays from the B frame, the setting value of the B frame may be stored first. Alternatively, when a rewritable register is rewritten immediately after the mode switching signal is input, the set value may be stored first in the G frame register 508 at the timing 607. In this case, the set value is stored in the B frame register 509 at the timing 608 and in the R frame register 507 at the timing 609.

  In this way, the projector using the DMD panel of this embodiment performs correction and setting values for correction of a frame of a color different from the displayed frame, so that an increase in circuit scale can be suppressed. become able to.

  Further, in the present embodiment, the projector has been described. However, any display device having a DMD panel may be applied to, for example, a rear projection projector, a television, a display, a digital camera, a portable game machine, a mobile phone, and the like. it can.

(Other examples)
The object of the present invention is not limited to the projectors as in the first and second embodiments, but a display in which one frame image is amplified to two or more frames and the two or more frames are displayed in a time division manner. It is also achieved by the device.

  Example 1 relates to a vertical alignment mode liquid crystal modulation element, but the applied voltage control of the above example is modified to a form suitable for a liquid crystal modulation element of TN, STN, OCB type other than the vertical alignment mode. The present invention may be applied to these liquid crystal modulation elements. Further, the present invention may be carried out by modifying it into a form suitable for a transmissive liquid crystal modulation element.

  It goes without saying that the object of the present invention can also be achieved by supplying a storage medium storing software program codes for realizing the functions of the above-described embodiments to the apparatus. At this time, the computer (or CPU or MPU) including the control unit of the supplied apparatus reads and executes the program code stored in the storage medium.

  In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the program code itself and the storage medium storing the program code constitute the present invention.

  As a storage medium for supplying the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, the OS (basic system or operating system) running on the apparatus performs part or all of the processing based on the instruction of the program code described above, and the functions of the above-described embodiments are realized by the processing. Needless to say, cases are also included.

  Further, the program code read from the storage medium may be written into a memory provided in a function expansion board inserted into the apparatus or a function expansion unit connected to the computer, and the functions of the above-described embodiments may be realized. Needless to say, it is included. At this time, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.

It is a block diagram of a liquid crystal projector to which the present invention is applied. FIG. 3 is a block diagram of an image processing unit of the projector according to the first embodiment. FIG. 6 is a sequence diagram for explaining register setting timing according to the first exemplary embodiment. It is a block diagram of a DMD projector to which the present invention is applied. FIG. 6 is a block diagram of an image processing unit of a projector according to a second embodiment. FIG. 10 is a sequence diagram for explaining register setting timings according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Control part 102 Data bus 103 Operation part 104 Power supply part 105 Input part 106 Image processing part 107 Liquid crystal drive part 108 Liquid crystal part 109 Light source 110 Light source control part 111 Projection optical system 112 Optical system control part 113 Temperature detection part 114 Timer 115 Optical sensor

Claims (5)

An input means for acquiring a video signal to be displayed;
Generating means for generating an image of two or more frames from an image of one frame of the video signal acquired by the input unit;
Storage means for storing a setting value corresponding to an image of each of the two or more frames used for image processing of each of the two or more frames generated by the generating means;
Image processing means for performing image processing on each of the two or more frames based on the setting value stored by the storage means;
Display means for displaying the image processed by the image processing means;
Control means for storing, in the storage means, setting values corresponding to images of frames other than the one frame during display of the image of one frame among the images of two or more frames. apparatus. The display means uses a liquid crystal panel that performs AC driving,
The generation means generates a frame image for positive polarity and a frame image for negative polarity from one frame image of the video signal,
2. The display device according to claim 1, wherein the control unit stores the set value corresponding to the image of the negative polarity frame in the storage unit during display of the image of the positive polarity frame. . The display means uses a DMD panel provided with a micromirror in pixel units,
The generation means generates a plurality of color frame images from one frame image of the video signal,
The said control means memorize | stores in the said memory | storage means the said setting value corresponding to the image of the color frame different from the image of the color frame currently displayed by the said display means. Display device. The generation unit generates a red frame image, a blue frame image, and a green frame image from one frame image of the video signal,
4. The control unit stores the setting value corresponding to the blue frame image or the green frame image in the storage unit during display of a red frame image. Display device.   The display device according to claim 1, wherein the image processing is processing for correcting gamma characteristics of an image.

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