JP2008292905A - Driving device for image display apparatus, its driving method, projection type display apparatus and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving device for image display apparatus, which suppresses an out-of-focus image with a simple configuration. <P>SOLUTION: The driving device for image display apparatus drives the display of an image display apparatus having a plurality of pixels arrayed in an image display region. A data distribution means performs distribution into an image data of the present frame and data corresponding to an image data preceding the present frame by one frame and a correction means performs overdrive based on the data corresponding to the image data of one frame preceding the present frame. A writing means writes data having a prescribed gradation apart from the image data for which the overdrive is performed. A starting gradation from the preceding frame is thereby confined into a prescribed range. Thus, the capacity of frame memory in which the data preceding the present frame by one frame is stored is reduced, and the out-of-focus image is suppressed with a simple configuration. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image display device drive device, a drive method thereof, a projection display device, and an electronic apparatus.

  In a hold-type display image display device such as a liquid crystal display device, it is known that moving image blur occurs when the same image is displayed in a frame period. Patent Document 1 describes a technique for improving such moving image blur by appropriately using an impulse display that shortens an image display period. Specifically, in this technique, an image display period is set by using a driving method (hereinafter also referred to as “black insertion driving” or “black insertion”) in which data for black display is written before image data is written. It is shortened.

  Another cause of motion blur in a liquid crystal display device is the slow response of the liquid crystal. Patent Document 2 describes a technique for improving moving image blurring by using “overdrive” that applies a voltage higher than the voltage corresponding to the gradation of the current image data to speed up the response of the liquid crystal. Has been.

JP 2005-49819 A Japanese Patent No. 2616652

  In the black insertion drive described in Patent Document 1 described above, the longer the time for writing black display data is, the closer it is to impulse-type display, so that it is possible to improve the motion blur, but the problem is that the brightness decreases. In addition, the overdrive described in Patent Document 2 requires a frame memory having a large storage capacity for holding video information of the previous frame and a lookup table for comparing current video information. In some cases, the cost would increase.

  The present invention has been made in view of the above points, and provides an image display device drive device, a drive method, an image display device, and a projection display device that can suppress image blurring with a simple configuration. One of the purposes.

  In one aspect of the present invention, a driving apparatus for displaying and driving an image display apparatus having a plurality of pixels arranged in an image display area includes image data of a current frame and one frame before the current frame. A data distribution unit that distributes the image data to the data corresponding to the image data; a storage unit that stores data corresponding to the image data of the previous frame; and the image data of the current frame that is stored in the storage unit Correction means for overdrive correction based on data corresponding to the image data before the frame, and image data corrected by the overdrive by the correction means are written to the image display device, and the overdrive corrected image data Write processing for writing data having a predetermined gradation to the image display device separately from Characterized in that it comprises a means.

  The drive device for the image display device described above is preferably used to display and drive an image display device having a plurality of pixels arranged in the image display area. Specifically, the data distribution unit distributes the image data of the current frame and the data corresponding to the image data of the previous frame with respect to the current frame, and the storage unit corresponds to the image data of the previous frame. Store the data. Then, the correcting unit corrects based on data corresponding to the image data of the previous frame. Specifically, the correction means performs overdrive. Further, the writing means performs a process of writing data having a predetermined gradation separately from the overdrive corrected image data. By performing such writing, the start gradation from the previous frame (the gradation at which response starts in the previous frame) can be limited to a predetermined range. This makes it possible to reduce the amount of data supplied to the storage unit and the correction unit. Therefore, according to the driving device of the image display device, it is possible to suppress image blurring with a simple configuration.

  Preferably, in the driving device of the image display device, the data distribution unit outputs data generated by reducing the amount of information included in the original image data as data corresponding to the image data of the previous frame. To do.

  In one aspect of the driving device of the image display device, the data distribution unit is based on at least one of a gradation value in the data having the predetermined gradation and a time for writing the data having the predetermined gradation. Thus, data corresponding to the image data of the previous frame is generated. In other words, the data distribution unit generates image data after reducing the amount of information that can be reduced by the data written by the writing unit.

  In another aspect of the driving device of the image display device, the data corresponding to the image data of the previous frame is expressed by a predetermined gradation. This makes it possible to more efficiently reduce the capacity of the storage means.

  In the driving device of the image display device, the writing unit writes the data having the predetermined gradation before writing the overdrive corrected image data, thereby setting the start gradation from the previous frame to a predetermined value. It is preferable to limit to the range. In this case, the writing means adjusts the start gradation by changing a region on the display image into which the data having the predetermined gradation is inserted.

  More preferably, the writing means writes black display data as the data having the predetermined gradation. That is, the writing unit performs black insertion driving. As a result, according to the driving device of the image display device described above, it is possible to simultaneously realize hold type display improvement by black insertion and liquid crystal response improvement by overdrive at a slight cost increase and obtain a good moving image. . That is, it is possible to simultaneously improve the liquid crystal response and the moving image blur due to the hold-type display, and to effectively suppress the cost increase necessary for realizing the overdrive and the brightness decrease due to the black insertion drive.

  In the driving device of the image display device, it is preferable that the writing unit adjusts the start gradation by changing a gradation value in the data having the predetermined gradation.

  The data distribution means is preferably a selector, and the storage means is preferably a frame memory.

  Moreover, it is preferable that the drive device for the image display device is applied to a projection display device including an illumination device and a projection device that projects light modulated by the drive device for the image display device.

  Furthermore, the drive device for the image display device described above can be suitably applied to various electronic devices.

  In another aspect of the present invention, a driving method for driving a display of an image display device having a plurality of pixels arranged in an image display area includes image data of a current frame and one frame before the current frame. A data distribution step of allocating data corresponding to the image data of the first frame, a storage step of storing data corresponding to the image data of the previous frame, and the image data of the current frame stored in the storage step A correction process for overdrive correction based on data corresponding to the image data before the frame, and the image data that has been overdrive corrected by the correction process is written to the image display device, and the overdrive corrected image data Writing that performs processing for writing data having a predetermined gradation separately to the image display device Includes a degree, the. Also by the driving method of the driving device of the image display device described above, the memory capacity required for overdrive can be reduced, and image blurring can be suppressed with a simple configuration.

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

[Device configuration]
FIG. 1 is a block diagram showing a schematic configuration of a liquid crystal projector 1000 to which a drive device for an image display apparatus according to this embodiment is applied. The liquid crystal projector 1000 mainly includes a light source 1100, dichroic mirrors 1108a and 1108b, a reflection mirror 1106, relay lenses 1122, 1123 and 1124, liquid crystal panels 14R, 14G and 14B, a cross dichroic prism 1112, and a projection lens. A system 1114. The liquid crystal projector 1000 is configured as a three-plate projection type liquid crystal device using three liquid crystal panels 14R, 14G, and 14B that function as liquid crystal light valves.

  The light source 1100 corresponds to an illumination device, and includes a lamp 1102 such as a metal halide and a reflector 1101 that reflects light from the lamp 1102. The blue light / green light reflecting dichroic mirror 1108a transmits only red light of white light from the light source 1100 and reflects blue light and green light. The transmitted red light is reflected by the reflection mirror 1106 and is incident on the liquid crystal panel 14R (hereinafter also referred to as “red liquid crystal panel 14R”).

  On the other hand, of the light reflected by the dichroic mirror 1108a, the green light is reflected by the dichroic mirror 1108b reflecting green light and enters the liquid crystal panel 14G (hereinafter also referred to as “green liquid crystal panel 14G”). On the other hand, the blue light also passes through the dichroic mirror 1108b. For blue light, in order to compensate for the difference in optical path length from green light and red light, light guide means 1121 comprising a relay lens system including an incident lens 1122, a relay lens 1123, and an output lens 1124 is provided, Through these, the blue light is incident on the liquid crystal panel 14B (hereinafter also referred to as “blue liquid crystal panel 14B”).

  The red liquid crystal panel 14R, the green liquid crystal panel 14G, and the blue liquid crystal panel 14B function as so-called liquid crystal light valves. Hereinafter, when these are used without distinction, they are simply referred to as “liquid crystal panel 14”. The liquid crystal panel 14 is a liquid crystal panel that is hermetically sealed with a liquid crystal that is an electro-optical material on a pair of transparent glass substrates. The liquid crystal panel 14 modulates the polarization direction of incident light according to the supplied image data. The liquid crystal panels 14R, 14G, and 14B modulate incident light according to the supplied image signal for each color light. Each of the liquid crystal panels 14R, G, and B is a monochrome display liquid crystal panel, and a common liquid crystal panel is used.

  Three lights modulated by each liquid crystal panel 14 enter the cross dichroic prism 1112. In this prism, four right-angle prisms are bonded together, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape on the inner surface thereof. These dielectric multilayer films combine the three color lights to form light representing a color image. The synthesized light is projected onto the screen 1120 by the projection lens system 1114 which is a projection optical system, and the image is enlarged and displayed. The projection lens system 1114 corresponds to a projection device.

  Next, a circuit for driving the liquid crystal panel 14 will be described with reference to FIG. FIG. 2 is a block diagram showing a schematic configuration of the scanning line driving circuit 11 and the data line driving circuit 12 that drive the liquid crystal panel 14.

  As shown in FIG. 2, the driving circuit 10 controls the scanning line driving circuit 11 and the data line driving circuit 12, and the scanning line driving circuit 11 and the data line driving circuit 12 controls the liquid crystal panel 14. Specifically, the drive circuit 10 acquires a clock signal clk, a vertical scanning signal VS, a horizontal scanning signal HS, and image data D. The vertical scanning signal VS corresponds to the vertical synchronizing signal, the horizontal scanning signal HS corresponds to the horizontal synchronizing signal, and these are input together with the image data D (image signal). The drive circuit 10 generates a start pulse DY, a scanning transfer clock CLY, a data transfer clock CLX, and a data signal Ds based on these acquired signals. The start pulse DY is a pulse signal output at the scanning start timing with respect to the scanning side (Y side). The scanning-side transfer clock CLY is a signal that defines horizontal scanning on the scanning side (Y side). The data transfer clock CLX is a signal that defines the timing for transferring data to the data line driving circuit 12. The data signal Ds is data corresponding to the image data D. The drive circuit 10, the scanning line drive circuit 11, and the data line drive circuit 12 receive and input various signals in addition to those described above, but descriptions of those that are not particularly related to the present embodiment are omitted.

  The scanning line driving circuit 11 acquires the start pulse DY and the scanning side transfer clock CLY from the driving circuit 10 and outputs scanning signals G1, G2, G3,..., Gn to the scanning line 14a of the liquid crystal panel 14. Specifically, the scanning line driving circuit 11 transfers the start pulse DY supplied from the driving circuit 10 in accordance with the scanning side transfer clock CLY, and outputs the scanning signals G1, G2, G3,..., Gn to each of the scanning lines 14a. Sequentially and exclusively. In addition, the data line driving circuit 12 acquires the data transfer clock CLX and the data signal Ds from the driving circuit 10 and sends the data signals d1, d2, d3,..., Dm to the data line 14b of the liquid crystal panel 14. Output.

  The liquid crystal panel 14 (corresponding to the red liquid crystal panel 14R, the green liquid crystal panel 14G, and the blue liquid crystal panel 14B described above) includes a liquid crystal (LCD) and displays an image defined in the image signal. . Specifically, the liquid crystal panel 14 includes a scanning line 14a, a data line 14b, and a pixel 14c. Specifically, n scanning lines 14a are formed on the liquid crystal panel 14 so as to extend in the X (row) direction in FIG. 2, and m data lines 14b extend along the Y (column) direction. Is formed. The pixels 14c are provided corresponding to the intersections of the scanning lines 14a and the data lines 14b, and are arranged in a matrix. Each color liquid crystal panel 14 is configured by three identical black and white panels because the separated RGB light is supplied thereto.

[Driving method of liquid crystal panel]
Next, a driving method performed on the liquid crystal panel 14 in the present embodiment will be specifically described. In this embodiment, in order to improve the responsiveness of the liquid crystal, the liquid crystal is applied by applying a voltage higher than the voltage corresponding to the gradation in the image of the current frame (hereinafter referred to as “current frame”). The panel 14 is driven. That is, “overdrive” is used. Hereinafter, the overdrive according to the present embodiment will be specifically described.

  In the present embodiment, the image data of the current frame and the data corresponding to the image data of the previous frame with respect to the current frame are allocated, and the data corresponding to the image data of the previous frame is stored in the frame memory. Then, overdrive is performed on the image data of the current frame based on data corresponding to the image data of the previous frame stored in the frame memory. Further, in the present embodiment, the overdriven image data is written to the liquid crystal panel 14 and data having a predetermined gradation is written to the liquid crystal panel 14 separately from the image data. Specifically, before writing overdriven image data, black display data is written to the liquid crystal panel 14 (that is, “black insertion driving”, in other words, “black insertion” is executed). This is because the start gradation from the previous frame is limited to a predetermined range by changing the area on the display image in which the data for black display is written. Note that the start gradation corresponds to the gradation at which the response starts in the previous frame (that is, the gradation of the image data one frame before).

  When black insertion driving is performed as described above, the transmittance of the liquid crystal panel 14 tends to decrease. Accordingly, it can be said that the gradation corresponding to the transmittance when the black insertion driving is performed is reduced from the original gradation when the black insertion driving is not performed. That is, the start gradation from the previous frame can be limited to a predetermined range. Therefore, by performing such black insertion driving, the amount of information held in the original image data, not the original image data of the previous frame, is reduced as the data of the previous frame used for overdrive. It can be said that the image data generated by can be used. That is, it can be said that the image data after the amount of information that can be reduced by performing the black insertion drive is stored in the frame memory. Therefore, in this embodiment, the image data generated by reducing the amount of information included in the original image data is stored in the frame memory as data corresponding to the image data of the previous frame. That is, the image data of the previous frame is not stored as it is in the frame memory. Then, overdrive is performed on the image data of the current frame based on the data with the reduced information amount. As described above, according to the present embodiment, it is possible to suppress image blurring with a simple configuration. Further, the capacity of the frame memory can be reduced, and the cost increase necessary for realizing overdrive can be reduced.

  Here, with reference to FIG. 3 and FIG. 4, a driving method of the liquid crystal panel 14 according to the present embodiment will be specifically described.

  FIG. 3 is a diagram for specifically explaining black insertion driving. 3A shows the vertical scanning signal VS in one vertical period, FIG. 3B shows the start pulse DY, FIG. 3C shows the scanning side transfer clock CLY, and FIG. 3D and FIG. 3 (e) shows a display image example at an arbitrary time. In this example, in FIG. 3B, the start pulse DY1 corresponds to a black display start pulse, and the start pulses DY2a and DY2b correspond to an image display start pulse. Here, a case where one of the start pulse DY2a and the start pulse DY2b is used will be described as an example.

  FIG. 3D shows a display image when the start pulse DY2a is used, and FIG. 3E shows a display image when the start pulse DY2b is used. Here, in FIGS. 3D and 3E, the positions indicated by reference numerals B1a and B1b indicate positions where the scanning line is scanned by the start pulse DY1 at an arbitrary time, and reference numerals B2a and B2b. The positions indicated by indicate the positions where the scanning lines are scanned by the start pulses DY2a and DY2b, respectively, at an arbitrary time. Further, regions R1a and R1b indicate black display regions in which data for black display is written by the start pulse DY1, and regions R2a and R2b indicate image display regions in which image data is written by the start pulses DY2a and DY2b, respectively. Is shown. In this example, the polarity of the voltage (drive voltage) applied to the liquid crystal panel 14 is switched at a predetermined timing. Therefore, the display image includes a region where data is written with a positive voltage (positive region) and a region where data is written with a negative voltage (negative region).

  As is apparent from FIGS. 3D and 3E, it can be seen that the black display regions R1a and R1b are rewritten in time series with image display data. In addition, it can be seen that the ratio of the black display areas R1a and R1b in the display image (hereinafter referred to as “black insertion ratio”) differs depending on the timing of generation of the image display start pulses DY2a and DY2b. In this example, the black display area R1b occupies a larger proportion in the display image than the black display area R1a. In other words, it can be said that the time for black insertion is longer when the start pulse DY2b is used than when the start pulse DY2a is used. Therefore, the time for performing black insertion can be changed by changing the generation timing of the start pulse for black display. In other words, by adjusting the generation timing of the image display start pulse DY, it is possible to adjust the start gradation from the previous frame by changing the area on the display image to which the data for black display is written. Become.

  FIG. 4 is a diagram for explaining that the image data used for overdrive can be reduced by writing black display data. Specifically, FIG. 4A is a diagram illustrating a relationship between a response from a transmittance of 100% to a transmittance of 0% and the transmittance. In other words, the relationship between the black insertion time (horizontal axis) and the liquid crystal transmittance (vertical axis) is shown. FIG. 4B is a diagram showing the relationship between the input gradation (horizontal axis) and the liquid crystal transmittance (vertical axis). The relationship shown in FIGS. 4A and 4B is an example, and is determined by the characteristics of the liquid crystal panel 14. Also, here, a case where one frame is 16.6 (ms) and the reference gradation is 10 bits (1024) is taken as an example.

  From FIG. 4A, it can be seen that, for example, when black insertion is performed for 2 (ms), the transmittance falls to 40%. It can be seen that the transmittance of 40% corresponds to “512” in the input gradation with reference to FIG. From this, it is understood that the start gradation from the previous frame can be limited to a predetermined range by performing the black insertion as described above before writing the image data. In other words, by performing black insertion as shown in this example, it is not necessary to use image data having the original input gradation of “1024” as data one frame before used for overdrive. It can be said that image data having an input gradation of “512” may be used. In other words, it can be said that image data obtained by reducing 10-bit image data to 9 bits can be used for overdrive even when black transmission does not respond completely to 0% transmittance. In this case, the image data with the information amount reduced to 9 bits may be stored in the overdrive frame memory.

  As described above, in the present embodiment, by using the image data in which the information amount of the original image data is reduced by limiting the start gradation from the previous frame to a predetermined range by writing the data for black display. Perform overdrive. As a result, the capacity of the frame memory for storing the image data can be reduced, and the cost increase necessary for realizing the overdrive can be reduced.

  Such overdrive is executed by the drive circuit 10 described above (see FIG. 2). Here, the configuration of the drive circuit 10 will be specifically described with reference to FIG.

  FIG. 5 is a block diagram showing a schematic configuration of the drive circuit 10 according to the present embodiment. The drive circuit 10 mainly includes a control unit 200, a selector unit 201, a frame memory 202, an overdrive LUT (lookup table) 203, and a D / A converter 204. FIG. 5 shows an excerpt of the main part of the characteristic component of the present application in the drive circuit 10.

  The drive circuit 10 is applied to the above-described liquid crystal projector 1000 or the like, and executes drive control for the liquid crystal panel 14 (corresponding to the above-described red liquid crystal panel 14R, green liquid crystal panel 14G, and blue liquid crystal panel 14B). The drive circuit 10 performs overdrive as described above, and functions as a drive device for the image display device according to the present invention. That is, the drive circuit 10 functions as data distribution means, storage means, correction means, and writing means in the present invention. The drive circuit 10 incorporates a frequency dividing circuit (not shown), a multiplication circuit including a PLL (Phase-locked loop), and the like, and is configured to generate a control signal necessary for driving the liquid crystal panel 14. ing.

  The control unit 200 acquires the clock signal clk, the vertical scanning signal VS, and the horizontal scanning signal HS (see FIG. 2), and starts the start pulse DY, the scanning side transfer clock CLY, the data transfer clock CLX, and the like. Is generated. Based on these signals, the control unit 200 supplies control signals for controlling the selector unit 201, the frame memory 202, and the D / A converter 204. For example, the control unit 200 supplies the selector unit 201 with a control signal s 1 that defines the timing at which the selector unit 201 writes data to the frame memory 202.

  The selector unit 201 acquires image data D1 (corresponding to the image data of the current frame), and distributes the image data to the image data of the current frame and data corresponding to the image data one frame before the current frame I do. Then, the selector unit 201 supplies the sorted image data D2 of the current frame to the overdrive LUT 203 and writes the data D3 corresponding to the image data of the previous frame in the frame memory 202. In this case, the selector unit 201 writes the data D3 into the frame memory 202 based on the control signal s1 supplied from the control unit 200.

  Specifically, the selector unit 201 stores the image data generated by reducing the amount of information included in the original image data in the frame memory 202 as data D3 corresponding to the image data of the previous frame. In this case, the selector unit 201 generates data D3 based on the stored lookup table. Specifically, the selector unit 201 refers to a lookup table in which image data D1 of the current frame to be input and data D3 to be output are associated, and data D3 corresponding to the input image data D1. Is output. This look-up table stores data after reducing the amount of information that can be reduced by performing black insertion driving. The information amount that can be reduced is the number of gradations.

  Note that the look-up table used by the selector unit 201 is information on the data D3 after the black insertion according to the input image data D1 of the current frame and the black insertion time (in other words, the black insertion ratio). Since the amount is determined, it is created based on such a relationship. The selector unit 201 can have a plurality of lookup tables according to the time for performing black insertion, and can switch between the plurality of lookup tables based on the time for actually performing black insertion. This is because the amount of information that can be reduced by black insertion changes depending on the time for black insertion.

  The frame memory 202 stores data D3 corresponding to the image data of the previous frame supplied from the selector unit 201. Then, the frame memory 202 outputs data D4 corresponding to the stored data D3 to the overdrive LUT 203 at the timing of the control signal s2 supplied from the control unit 200.

  The overdrive LUT 203 acquires the image data D2 of the current frame from the selector unit 201, and acquires data D4 corresponding to the image data of the previous frame from the frame memory 202. The overdrive LUT 203 performs overdrive on the image data D2 of the current frame. Specifically, the overdrive LUT 203 performs overdrive based on a stored lookup table. Specifically, the overdrive LUT 203 obtains image data D5 corresponding to the image data D2 and data D4 based on the look-up table, and outputs this to the D / A converter 204. Then, the D / A converter 204 converts the input image data D5 from a digital signal to an analog signal and supplies it to the liquid crystal panel 14.

  According to the drive circuit 10 described above, the input bits to the frame memory 202 and the overdrive LUT 203 are defined by limiting the start gradation from the previous frame by writing the black display data before writing the image data. The number can be reduced. In addition, the drive circuit 10 can simultaneously realize hold-type display improvement by black insertion and liquid crystal response improvement by overdrive at a slight cost increase and obtain a good moving image. That is, it is possible to simultaneously improve the liquid crystal response and the moving image blur due to the hold-type display, and to effectively suppress the cost increase necessary for realizing the overdrive and the brightness decrease due to the black insertion drive.

[Modification]
In the above example, black insertion is performed for 2 (ms) (see FIG. 4). In other examples, black insertion can be performed for a time longer than 2 (ms). For example, 4 (ms) black insertion may be performed on the liquid crystal panel 14 having display characteristics as shown in FIG. In this case, as shown in FIG. 4A, it can be seen that when 4 (ms) of black is inserted in one frame (16.6 ms), the transmittance falls to 0%. When such black insertion is performed, it can be assumed that the image data of one frame before has a uniform 0 gradation. That is, it is considered that the response of the previous frame always starts from 0 gradation. As described above, when the time for writing the data for black display is set to be a relatively long time, it is not necessary to store the data corresponding to the image data of the previous frame in the frame memory 202 in order to perform overdrive. This can be said (note that the time for writing data for black display is defined according to the display characteristics of the liquid crystal panel 14). That is, a drive circuit that performs overdrive can be configured without using the frame memory 202.

  Note that the time for writing the data for black display may be fixed to a predetermined time or may be changed according to the input image data. When changing the time for writing black display data in accordance with the input image data, an appropriate writing time is determined by performing feedback control based on the input image data, etc. Can do. Then, the selector unit refers to the lookup table that stores the black display data in association with the writing time, and reduces the amount of information included in the original image data by an amount corresponding to the determined time. The processed image data is output to the frame memory.

  In the above description, data using black display data is shown as data to be written to the liquid crystal panel 14 separately from the overdriven image data. However, the present invention is not limited to this. In another example, data for white display can be used instead of data for black display. In yet another example, a color represented by a gray scale other than black or white can be used. Also by writing these data, the start gradation from the previous frame can be appropriately limited to a predetermined range.

  Furthermore, it is not limited to fixing the gradation of data written to the liquid crystal panel 14 to one such as black or white. In another example, the gradation value of data written to the liquid crystal panel 14 can be changed. For example, the gradation value in the gray scale can be changed.

  FIG. 6 is a diagram showing a specific example when the gradation value of data written to the liquid crystal panel 14 is changed. 6A shows the vertical scanning signal VS in one vertical period, FIG. 6B shows the start pulse DY, FIG. 6C shows the scanning-side transfer clock CLY, FIG. 6D and FIG. 6 (e) shows a display image example at an arbitrary time. In FIG. 6B, the start pulse DY3 corresponds to a start pulse used separately from the image display, and the start pulse DY4 corresponds to an image display start pulse. Specifically, in this example, the gradation value of the data to be written is changed using the start pulse DY3. In this example, the time difference T1 between the generation timings of the start pulse DY3 and the start pulse DY4 is fixed. That is, instead of changing the start pulse generation timing, the gradation value of the data written to the liquid crystal panel 14 is changed.

  Specifically, FIG. 6D shows a display image when dark gray is used as data to be written using the start pulse DY3, and FIG. 6E shows light gray as data to be written using the start pulse DY3. A display image when used is shown. Here, in FIGS. 6D and 6E, the positions indicated by reference characters B3a and B3b indicate the positions where the scanning line is scanned by the start pulse DY3 at an arbitrary time, and reference characters B4a and B4b. The position indicated by indicates a position where the scanning line is scanned by the start pulse DY4 at an arbitrary time. Since the time difference T1 between the generation timings of the start pulse DY3 and the start pulse DY4 is fixed, the positions on the display image indicated by reference numerals B4a and B4b are substantially the same. Further, regions R3a and R3b indicate display regions in which data having a predetermined gradation is written by the start pulse DY3, and regions R4a and R4b indicate image display regions in which image data is written by the start pulse DY4. Show. In this example, the polarity of the voltage (drive voltage) applied to the liquid crystal panel 14 is switched at a predetermined timing. Therefore, the display image includes a region where data is written with a positive voltage (positive region) and a region where data is written with a negative voltage (negative region).

  6D and 6E, the areas of the regions R3a and R3b are substantially the same, but the color densities in the display images corresponding to the regions R3a and R3b are different (that is, the gradations are different). I understand. This is because the time difference T1 between the generation timings of the start pulse DY3 and the start pulse DY4 is fixed, but the gradation value of the data to be written is changed using the start pulse DY3. As described above, the start gradation from the previous frame can also be appropriately adjusted by changing the gradation value of the data written to the liquid crystal panel 14. That is, the start gradation from the previous frame can be appropriately limited to a predetermined range. Note that the gradation value of data written to the liquid crystal panel 14 can be changed according to input image data or the like. In this case, image data in which the information amount of the original image data is reduced by an amount corresponding to the gradation value of the data to be written can be used for overdrive.

  In the above-described embodiment, the projector 1000 that is an image display device has been described as a three-plate projector including the three liquid crystal panels 14. However, for example, a color image is formed by one transmissive liquid crystal panel. A single-plate projector that projects

  In addition, the liquid crystal panel 14 that is the light modulation element of the projector 1000 has been described as a transmissive liquid crystal light valve, but is not limited thereto. For example, a configuration using LCOS (Liquid Crystal On Silicon), which is a kind of reflective liquid crystal panel, as the light modulation element may be used. In this case, the optical system of the projector 1000 needs to be configured in accordance with LCOS.

  Further, in the above description, the embodiment in which the present invention is applied to the liquid crystal projector 1000 is shown, but the present invention is not limited to this. That is, the present invention can be applied to other electronic devices. For example, the present invention can be applied to hold display type electronic devices such as a liquid crystal television, a mobile phone, and a personal computer (so-called notebook personal computer).

  Even with these configurations, operations and effects equivalent to the operations and effects in the above-described embodiments can be obtained.

It is a block diagram which shows schematic structure of a liquid crystal projector. It is a figure which shows schematic structures, such as a scanning line drive circuit and a data line drive circuit. It is a figure for demonstrating a black insertion drive concretely. It is a figure which shows an example of the relationship between black insertion time and a transmittance | permeability, and the relationship between an input gradation value and a transmittance | permeability. It is a block diagram which shows schematic structure of the drive circuit which concerns on this embodiment. It is a figure for demonstrating the case where the gradation value of the data written in a liquid crystal panel is changed.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Drive circuit, 11 Scan line drive circuit, 12 Data line drive circuit, 14 Liquid crystal panel, 14a Scan line, 14b Data line, 14c Pixel, 200 Control part, 201 Selector part, 202 Frame memory, 203 Overdrive LUT, 1000 LCD projector

Claims (12)

A drive device for driving to display an image display device having a plurality of pixels arranged in an image display region,
Data distribution means for distributing image data of a current frame and data corresponding to image data one frame before the current frame;
Storage means for storing data corresponding to the image data of the previous frame;
Correction means for overdriving the image data of the current frame based on data corresponding to the image data of the previous frame stored in the storage means;
A process of writing image data that has been overdrive corrected by the correction means to the image display device and writing data having a predetermined gradation separately from the image data that has been overdriven corrected to the image display device An image display device driving device comprising: a writing unit configured to perform   2. The image according to claim 1, wherein the data distribution unit outputs data generated by reducing the amount of information included in the original image data as data corresponding to the image data of the previous frame. Drive device for display device.   The data distribution means is data corresponding to the image data of the previous frame based on at least one of a gradation value in the data having the predetermined gradation and a time for writing the data having the predetermined gradation. The image display device driving device according to claim 1, wherein the image display device driving device is generated.   4. The image display device drive device according to claim 1, wherein data corresponding to the image data of the previous frame is expressed by a predetermined gradation. 5.   The writing means limits the start gradation from a previous frame to a predetermined range by writing data having the predetermined gradation before writing the overdrive corrected image data. Item 5. The drive device for an image display device according to any one of Items 1 to 4.   6. The driving of the image display device according to claim 5, wherein the writing unit adjusts the start gradation by changing a region on the display image into which the data having the predetermined gradation is inserted. apparatus.   7. The driving device for an image display device according to claim 1, wherein the writing unit writes black display data as the data having the predetermined gradation.   6. The image display apparatus driving device according to claim 5, wherein the writing unit adjusts the start gradation by changing a gradation value in the data having the predetermined gradation. The data distribution means is a selector,
9. The drive device for an image display device according to claim 1, wherein the storage means is a frame memory.   An illumination device, a drive device for an image display device according to any one of claims 1 to 9 that modulates light emitted from the illumination device, and light that is modulated by the drive device for the image display device is projected. A projection-type display device.   An electronic apparatus comprising the drive device for an image display device according to claim 1. A driving method for driving to display an image display device having a plurality of pixels arranged in an image display area,
A data distribution step for distributing the image data of the current frame and the data corresponding to the image data one frame before the current frame;
A storage step of storing data corresponding to the image data of the previous frame;
A correction step of overdriving the image data of the current frame based on data corresponding to the image data of the previous frame stored in the storage step;
A process of writing image data subjected to overdrive correction in the correction step to the image display device and writing data having a predetermined gradation separately from the image data subjected to overdrive correction to the image display device. And a writing process for performing an image display device.