JP2011053698A - Liquid crystal device, drive method, direct-view display device, and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of displaying a desired gradation as fast as possible by appropriately compensating optical response characteristics of a liquid crystal device and having little degradation in a displayed image; and to provide a drive method of the liquid crystal device, and a direct-view display device and a projector. <P>SOLUTION: The liquid crystal device displays an image by supplying an input image signal to a plurality of pixels. One frame period of an input image signal is divided into s (where s is a natural number of 2 or more) of display periods, and among the s of display periods, at least one display period has a length different from that of other display periods. In the s of display periods, a positive polarity potential or a negative polarity potential is applied to a pixel, and in continuous t (where t is a natural number of 2 or more) of frame periods, the total time of applying the positive polarity potential to the pixel is almost equal to the total time of applying the negative polarity potential to the pixel. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a liquid crystal device, a driving method of the liquid crystal device, and a direct-view display device and a projector using the liquid crystal device.

  There is known a driving method of a liquid crystal device that appropriately compensates for optical response characteristics of the liquid crystal device and displays a desired gradation as fast as possible. Specifically, a drive voltage that is higher (overshooted) than the gradation voltage for the input image signal of the current frame determined in advance according to the combination of the input image signal of the previous frame and the input image signal of the current frame, Alternatively, the driving method supplies a low (undershoot) driving voltage, that is, a corrected driving voltage to the liquid crystal display panel.

  However, in this driving method, the corrected driving voltage is applied to the current frame on the assumption that the liquid crystal has reached the transmittance (target gradation luminance) determined by the input image signal one frame before. In general, when considering the variation in the thickness of the liquid crystal cell and the temperature dependence of the response speed of the liquid crystal, it is not possible to cause the liquid crystal to reach the transmittance (target gradation luminance) determined by the input image signal one frame before at high speed. Have difficulty. For this reason, in the situation where the liquid crystal does not reach the transmittance (target gradation luminance) determined by the input image signal one frame before, there is a possibility that the image quality of the display image is deteriorated when such a driving method is used.

As a solution to this problem, a driving method described below is disclosed.
First, one frame period of the input image signal is divided into a first display period and a second display period, and an emphasis conversion signal that causes the liquid crystal display panel to reach the transmittance determined by the input image signal after the first display period has elapsed. Ask. Then, the obtained enhancement conversion signal is supplied to the liquid crystal display panel in the first display period, and the input image signal is supplied to the liquid crystal display panel in the second display period. (See Patent Document 1).
According to this method, even if an error occurs in the actual reached gradation luminance in the first display period, the input image signal is supplied to the liquid crystal display panel as it is in the second display period, so that in the first display period. The generated error can be corrected (absorbed) to reach the transmittance (target gradation luminance) determined by the input image signal.
Further, Patent Document 1 discloses a configuration of a liquid crystal device in which the ratio of the first and second display periods in one frame period of the input image signal is arbitrarily set. Thereby, according to the optical response characteristic of a liquid crystal display panel, optimal liquid crystal response and fidelity can be realized, and high-quality image display can be obtained. Specifically, as shown in FIG. 17 of Patent Document 1, the start timing of the second image display period (writing scan timing of the input image signal) is advanced compared to the start timing of the second image display period described above. Compared with a display method in which the start timing of the second image display period is not advanced, a desired gradation can be displayed as fast as possible.

JP 2004-240410 A

  By the way, the liquid crystal device applies a voltage to the liquid crystal to change the liquid crystal to a desired gradation. However, if a voltage is applied to the liquid crystal for a long time, the charge biased to the liquid crystal accumulates and a display malfunction occurs. By reversing the direction (polarity) of the voltage every time a signal is written, the charge biased in the liquid crystal is prevented from accumulating. Therefore, when the start timing of the second image display period (input image signal writing scan timing) is advanced as in the liquid crystal device disclosed in FIG. Since there is a difference between the period and the second display period, there is a problem in that charges that are biased in the liquid crystal are accumulated and a problem occurs in display.

  The present invention has been made in view of the above problems, and an object of the present invention is to appropriately compensate for the optical response characteristics of a liquid crystal device so that a desired gradation can be displayed as fast as possible, and the display image can be displayed. A display with little deterioration is realized. In general, the deterioration of the display image becomes more conspicuous as the screen becomes larger. In particular, the present technology is effective for a projector that projects and enlarges the display image by the liquid crystal device by the projection unit. This technology can also be used for a direct-view display device for visual recognition.

  In order to solve the above-described problem, the present invention provides a liquid crystal device that displays an image by supplying an input image signal to a plurality of pixels, wherein one frame period of the input image signal is s (s is 2 or more). Natural number) display periods and at least one of the s display periods has a different length from the other display periods, and the s display In the period, a positive potential or a negative potential is applied to the pixel, and the total application time of the positive potential to the pixel in a plurality of consecutive t (t is a natural number of 2 or more) frame periods. And the negative electrode potential application time are substantially equal to each other.

  According to this configuration, since one frame period of the input image signal is divided into a plurality of s display periods having different lengths, the start timing of the second and subsequent display periods (writing scan of the input image signal) (Timing) can be advanced. Thereby, a desired gradation can be displayed as fast as possible. On the other hand, when one frame period is divided into a plurality of s display periods having different lengths, the application time of the positive potential is different from the application time of the negative potential, so that the charge biased to the liquid crystal in one frame period. Accumulates. On the other hand, in the present invention, in the total time of a plurality of consecutive one frame periods, the application time of the positive potential to the arbitrary pixel and the application time of the negative potential are substantially equal. The accumulation effect is avoided, and the display does not fail.

  In the liquid crystal device of the present invention, the s display periods include a first display period and a second display period, and the continuous t frame periods include a first frame period and a second frame period. In the first display period of the first frame period, a positive potential or a negative potential is applied to the pixel. In the second display period of the first frame period, the first potential is applied to the pixel. A potential having a polarity different from that applied to the pixel in the first display period of the frame period is applied, and in the first display period of the second frame period, the pixel has a first display period of the first frame period. In the second display period of the second frame period, a potential having a polarity different from the polarity applied to the pixel is applied to the pixel in the second display period of the first frame period. A potential having a polarity different from the polarity applied to the pixel is applied, and in the total time of the first frame period and the second frame period that are consecutive, the application time of the positive potential to the pixel and the negative potential It is also preferable that the application time be substantially equal.

  According to this configuration, when the potential is positive (negative) in the first display period of the first frame period, the potential becomes negative (positive) in the second display period of the first frame period, and the first potential in the second frame period. When the display period has a negative (positive) polarity potential, the potential becomes a positive (negative) polarity potential in the second display period of the second frame period. Therefore, the application time of the positive (negative) polarity potential in the first display period in the first frame period and the second display period in the second frame period, the second display period in the first frame period, and the second display period in the second frame period. The application time of the negative (positive) polarity potential with one display period is substantially equal. Therefore, in an arbitrary pixel, the application time of the positive potential and the application time of the negative potential are substantially equal in the total time of two consecutive one frame periods, so that the influence of accumulation of charges biased in the liquid crystal is avoided, The display is less prone to problems. Further, since the positive and negative polarities can be reversed with the length of two frame periods that are the shortest in this configuration, the influence of accumulation of charges biased on the liquid crystal can be minimized.

In the liquid crystal device of the present invention, the s display periods include a first display period and a second display period, and the continuous t frame periods include a first frame period and a second frame period. In the first display period of the first frame period, a positive potential or a negative potential is applied to the pixel. In the second display period of the first frame period, the first potential is applied to the pixel. A voltage having the same polarity as that applied to the pixel in the first display period of the frame period is applied, and in the first display period of the second frame period, the pixel has a first display period of the first frame period. In the second display period of the second frame, the pixel is applied with the image in the second display period of the first frame period. Applied polarities different polarity voltage is applied to,
It is also preferable that the application time of the positive potential and the application time of the negative potential to the pixels be substantially equal in the total time of the continuous first frame period and the second frame period.

  According to this configuration, when the potential is positive (negative) in the first display period of the first frame period, the potential is positive (negative) in the second display period of the first frame period, and the first frame period is the first. When the display period has a negative (positive) polarity potential, the potential becomes a negative (positive) polarity potential in the second display period of the second frame period. Therefore, the application time of the positive (negative) polarity potential in the first display period and the second display period in the first frame period, and the negative (positive) polarity in the first display period and the second display period in the second frame period. The potential application time is substantially equal. Therefore, in an arbitrary pixel, the application time of the positive potential and the application time of the negative potential are substantially equal in the total time of two consecutive one frame periods, so that the influence of accumulation of charges biased in the liquid crystal is avoided, The display is less prone to problems. Further, since the positive and negative polarities can be reversed with the length of two frame periods that are the shortest in this configuration, the influence of accumulation of charges biased on the liquid crystal can be minimized.

  Further, the liquid crystal device of the present invention supplies an enhancement conversion signal in which the liquid crystal responds faster than when the input image signal is supplied toward the transmittance determined by the input image signal in the first display period, It is also preferable to supply an adjustment conversion signal for adjusting the response state of the liquid crystal after the enhancement conversion signal is input during the second display period.

  According to this configuration, the response of the liquid crystal can be improved at a higher speed by the enhancement conversion signal, and a desired gradation can be adjusted by the adjustment conversion signal for adjusting the response state of the liquid crystal after the enhancement conversion signal is input. Accordingly, the optical response characteristics of the liquid crystal device can be appropriately compensated so that a desired gradation can be displayed as fast as possible, and a display with little deterioration of the display image can be realized.

  The liquid crystal device of the present invention includes a plurality of data lines intersecting with each other and a plurality of scanning lines, and the pixels are connected to the data lines and the scanning lines, and have a positive polarity and a negative polarity. Is supplied to each of the plurality of data lines, and a plurality of pulse signals rising at different timings for each horizontal period are skipped over a part of the plurality of scanning lines. It is also preferred to supply each of the lines.

  When the start timing of the second display period (the writing scan timing of the input image signal) is advanced compared to the start timing of the second display period, the timing (input) The earlier the image signal writing scan timing), the faster the signal switching speed has to be, and the load is applied to the circuit. At the same time, the time for applying charges to the pixels cannot be secured, and the desired gradation display can be achieved. It becomes difficult. On the other hand, according to the present invention, it is not necessary to increase the signal switching speed even if the timing (input image signal writing scanning timing) is advanced. Therefore, it is easy to secure time for applying charges to the pixels, and display of a desired gradation is facilitated.

  The present invention is also a driving method of a liquid crystal device that displays an image by supplying an input image signal to a plurality of pixels, and s (s is a natural number of 2 or more) of one frame period of the input image signal. The display period is divided into a plurality of display periods, and at least one of the s display periods is set to a length different from that of the other display periods. A positive potential or a negative potential is applied, and in a plurality of consecutive t (t is a natural number of 2 or more) frame periods, the total application time of the positive potential to the pixel and the application time of the negative potential A configuration in which the total time is substantially equal is also preferable.

  When the start timing of the second display period (the writing scan timing of the input image signal) is advanced compared to the start timing of the second display period, the timing (input) The earlier the image signal writing scan timing), the faster the signal switching speed has to be, and the load is applied to the circuit. At the same time, the time for applying charges to the pixels cannot be secured, and the desired gradation display can be achieved. It becomes difficult. On the other hand, according to the present invention, it is not necessary to increase the signal switching speed even if the timing (input image signal writing scanning timing) is advanced. Therefore, it is easy to secure time for applying charges to the pixels, and display of a desired gradation is facilitated.

  A direct-view display device according to the present invention includes an illumination device and a light modulation device that modulates light emitted from the illumination device, and the light modulation device includes the liquid crystal device.

  According to this configuration, an image can be visually recognized by the illumination device and the light modulation device that modulates light emitted from the illumination device. At this time, the optical response characteristic is appropriately compensated so that a desired gradation can be displayed as fast as possible, and the liquid crystal device of the present invention capable of realizing a display with little deterioration of the display image is used for the light modulation device. Therefore, it is possible to realize a direct view display device that can visually recognize a very excellent image.

The projector of the present invention includes an illumination device, a light modulation device that modulates light emitted from the illumination device, and a projection unit that enlarges and projects a display image of the light modulation device, and the light modulation device is the liquid crystal. It consists of an apparatus.
In general, the deterioration of the display image becomes more conspicuous as the screen becomes larger. Accordingly, in a projector that projects an enlarged display image by the light modulation device using the projection unit, the optical response characteristic is appropriately compensated so that a desired gradation can be displayed as fast as possible, and the display image is not deteriorated. It is very effective to use the liquid crystal device of the present invention capable of realizing a small number of displays in a light modulation device.

It is a top view which shows schematic structure of the liquid crystal device of 1st Embodiment. FIG. 2 is a cross-sectional view of the liquid crystal device taken along line H-H ′ in FIG. 1. 2 is an equivalent circuit diagram of a plurality of pixels in the display area of the liquid crystal device. FIG. FIG. 2 is a block diagram including a driving circuit unit of the liquid crystal light valve. 2 is a circuit diagram illustrating a schematic configuration of a scan driver of the drive circuit unit. FIG. FIG. 6 is a detailed circuit diagram of the main part of the drive circuit diagram of FIG. 5; 4 is a timing chart for explaining the operation of the liquid crystal device. FIG. 8 is a timing chart of the main part of the drive circuit unit in FIG. 7. It is an image figure explaining the operation | movement written in a pixel similarly. It is an image figure which shows the arbitrary moments of the screen of a liquid crystal device. It is a figure which shows the screen of the operation | movement written in the pixel of a liquid crystal device. It is a figure which shows the screen of the operation | movement written in the pixel of the liquid crystal device of the modification 1 of 1st Embodiment. It is a figure which shows the screen of the operation | movement written in the pixel of the liquid crystal device of the modification 2 of 1st Embodiment. It is a figure which shows the polarity change of the screen of 1 frame period of the liquid crystal device of 2nd Embodiment. It is a figure which shows the polarity change of the screen of 1 frame period of the liquid crystal device of the modification of 2nd Embodiment. It is a figure which shows the polarity change of the screen of 1 frame period of the liquid crystal device of the modification of 2nd Embodiment. It is a figure which shows the polarity change of the screen of 1 frame period of the liquid crystal device of the modification of 2nd Embodiment. It is a figure which shows the screen of the operation | movement written in the pixel of the liquid crystal device of 3rd Embodiment. It is sectional drawing which shows schematic structure of a direct view type display apparatus. It is sectional drawing which shows schematic structure of a projector. It is a figure which shows the polarity change of the screen of 1 frame period of another liquid crystal device.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.
In this embodiment, an example of a liquid crystal light valve (liquid crystal device) used as a light modulation device of a projector will be described.

(Overall configuration of liquid crystal light valve)
FIG. 1 is a schematic configuration diagram of a liquid crystal light valve of the present embodiment, and FIG. 2 is a cross-sectional view taken along line HH ′ of FIG.
As shown in FIGS. 1 and 2, the configuration of the liquid crystal light valve 1 of the present embodiment is such that a sealing material 52 is provided along the edge of the counter substrate 20 on the TFT array substrate 10 and the inner side thereof. In parallel with this, a light shielding film 53 (peripheral parting) is provided as a frame. A data driver (data line driving circuit) 201 and an external circuit connection terminal 202 are provided along one side of the TFT array substrate 10 in a region outside the sealing material 52, and a scanning driver (scanning line driving circuit) 104 is provided. It is provided along two sides adjacent to this one side.

  Furthermore, a plurality of wirings 105 are provided on the remaining side of the TFT array substrate 10 for connecting the scan drivers 104 provided on both sides of the image display area. Further, at least one corner portion of the counter substrate 20 is provided with a vertical conductive material 106 for electrical conduction between the TFT array substrate 10 and the counter substrate 20. As shown in FIG. 2, the counter substrate 20 having substantially the same outline as the seal material 52 shown in FIG. 1 is fixed to the TFT array substrate 10 by the seal material 52, and the TFT array substrate 10, the counter substrate 20, In between, a liquid crystal layer 50 made of TN liquid crystal or the like is sealed. An opening 52 a provided in the sealing material 52 shown in FIG. 1 is a liquid crystal injection port and is sealed by the sealing material 25.

FIG. 3 is an equivalent circuit diagram of a plurality of pixels formed in a matrix form constituting a liquid crystal light valve.
As shown in FIG. 3, each of the plurality of pixels formed in a matrix forming the image display area of the liquid crystal light valve 1 according to the present embodiment has a pixel electrode 9 and a pixel electrode 9 for switching control. A TFT 30 is formed, and a data line 6 a to which an image signal is supplied is electrically connected to the source region of the TFT 30. The liquid crystal light valve 1 of the present embodiment has n data lines 6a and 4m scanning lines 3a (n and m are both natural numbers). The image signals S ₁ , S ₂ ,..., S _n to be written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group of a plurality of adjacent data lines 6a. Anyway.

Further, the scanning line 3a is electrically connected to the gate of the TFT 30, and the scanning signals G ₁ , G ₂ ,..., G _4m are jumped to each scanning line 3a at a predetermined timing as described later. It is comprised so that it may apply. The pixel electrode 9 is electrically connected to the drain of the TFT 30, and the image signal S ₁ , S ₂ ,... Supplied from the data line 6a is turned on by turning on the TFT 30 as a switching element for a certain period. writing S _n at a predetermined timing. Image signals S ₁ of a predetermined level written to the liquid crystal through the pixel electrodes _{9, S 2, ..., S} n is held for a predetermined period between the common electrode formed on the counter substrate 20. Here, in order to prevent the held image signal from leaking, a storage capacitor 70 is provided in parallel with the liquid crystal capacitor formed between the pixel electrode 9 and the common electrode.

FIG. 4 is a functional block diagram showing the main part of the drive circuit of the liquid crystal light valve.
As shown in FIG. 4, the drive circuit unit 60 of the liquid crystal light valve 1 of the present embodiment includes a controller 61, a first frame memory 62, and a second frame memory 63 in addition to the data driver 201 and the scan driver 104 described above. A frame memory for two screens and a D / A converter 64 are provided.

  One of the first frame memory 62 and the second frame memory 63 is for temporarily storing an image (image signal) for one frame inputted from the outside, and the other is used for display. The roles are switched for each frame.

  The controller 61 generates a clock signal CLK, a gate output pulse DY, an enable signal ENB, and the like based on the input vertical synchronization signal Vsync, horizontal synchronization signal Hsync, and dot clock signal dotclk. In addition, the controller 61 reads the input image signal DATA twice from the outside at twice the frame frequency, and supplies an image for one frame of the read image signal to the first frame memory 62 or the second frame memory 63. That is, one frame period of the input image signal DATA is divided into a first display period and a second display period, and the same image data for one frame is read twice in one vertical display period (one frame period). Write to the frame memory 62 or the second frame memory 63.

Next, the controller 61 generates the generated clock signal CLY, gate output pulse DY,
An enable signal ENB is supplied to the scan driver 104. The controller 61 supplies the generated clock signal CLK to the data driver 201, reads out the image signal from the first frame memory 62 or the second frame memory 63, and supplies the read image signal to the D / A converter.
The D / A converter 64 D / A converts the image signal supplied from the controller 61 and supplies it to the data driver 201. The image signal, the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, and the dot clock signal dotclk are signals configured based on information extracted from the input image signal. Here, one frame period of the input image signal is used. The period of the vertical synchronization signal Vsync is substantially equal.

FIG. 5 is a circuit diagram showing a schematic configuration of the scan driver in the drive circuit section, and FIG. 6 is a circuit diagram showing a schematic configuration of the shift register of the scan driver in FIG. In FIG. 6, a part of the scan driver of FIG. 5 is extracted and shown.
As shown in FIG. 5, the scan driver 104 is configured by a shift register 66 to which a gate output pulse DY, a clock signal CLY, and an inverted clock signal CLY ′ are input from the controller 61, and each of the above-described outputs output from the shift register 66. There are 4m AND circuits 67 to which signals are input, and 4m scanning lines 3a connected to each of the AND circuits 67.
Each of the AND circuits 67 is connected to a gate pulse signal line and one of four types of enable signals (ENB1, ENB2, ENB3, ENB4).

The enable signal ENB1 is connected to the AND circuits 67 _{(1) to} 67 _{( m)} , the enable signal ENB2 is connected to the AND circuits 67 _{(m + 1) to} 67 _(2m) , and the enable signal ENB3 is connected to the AND circuits 67 _{(2m + 1) to} 67. _The enable signal ENB4 is connected to the AND circuits 67 _{(3m + 1)} to _(4m) . Accordingly, the output signal from the shift register 66 and the enable signal ENB1 are input to the AND circuit 67 corresponding to the scanning signals G _{1 to} G _m , and the shift register is input to the AND circuit 67 corresponding to the scanning signals G _{m + 1 to} G _2m. 66 output signal and the enable signal ENB2 is input from the scanning signal _G 2m + 1 _{~G 3m} output signals from the shift register 66 and the enable signal ENB3 is input to the aND circuit 67 corresponding to the scanning signal _G 3m + 1 _{~G 4m} The AND circuit 67 corresponding to is configured to receive the output signal from the shift register 66 and the enable signal ENB4. As described above, the 4m scanning lines 3a correspond to the four types of enable signals ENB input to the AND circuit 67, the scanning signals G _{1 to} G _m , the scanning signals G _{m + 1 to} G _2m , and the scanning signal G. _2m + 1 _{~G 3m,} is divided into four blocks of scanning signal _G 3m + 1 _{~G 4m.} FIG. 6 shows the internal structure of the shift register 66.

(Operation of liquid crystal light valve)
FIG. 7 is a timing chart for explaining the operation of the liquid crystal light valve, and FIG. 8 is a timing chart showing an essential part in FIG. 7 (range A in FIG. 7).
As shown in FIG. 7, when the vertical synchronization signal Vsync is input once (during one vertical period), the controller 61 outputs the gate output pulse DY to the shift register twice in synchronization with the input vertical synchronization signal Vsync. Output. The first gate output pulse DY1 is a scan start start pulse in the first display period, and the second gate output pulse DY2 is a scan start start pulse in the second display period. The gate output pulse DY is shifted (scanned) in the shift register 66 of the scan driver 104 in synchronization with the clock signal CLY that rises one pulse every horizontal period. Accordingly, the second gate output pulse DY2 is input to the shift register after the first gate output pulse DY has shifted m scanning lines.

More specifically, as shown in FIG. 8 (range A in FIG. 7), the enable signal ENB1 and the enable signal ENB2 are in opposite phases, the enable signal ENB2 and the enable signal ENB3 are in opposite phases, and the enable signal ENB3. The enable signal ENB4 has an opposite phase. When the gate output pulse DY has passed the end of the region to be controlled by a different enable signal (specifically, _{G m, G 2m, G 3m} , scanning line _{G 4m),} respectively, enable signals ENB1, the enable signal ENB2 The phases of the enable signal ENB3 and the enable signal ENB4 are all inverted. Also, immediately after the first gate output pulse DY of the gate output pulse output twice during one vertical period passes through the end of the region controlled by a certain enable signal, the second gate output pulse DY is It passes through the beginning of the area controlled by the enable signal. As described above, the interval between the gate output pulses output twice during one vertical period is separated by m scanning lines.

Through the above operation, gate pulses are alternately output to two places on the screen separated by m scanning lines. That is, jumping to a scanning line that is m lines away from a predetermined scanning line returns to the scanning line that is next to the predetermined scanning line, and jumping to a scanning line that is m lines away from the scanning line The signals are sequentially output so as to return to the scanning line (that is, scanning signal G ₁ , scanning signal G _{m + 1} , scanning signal G ₂ , scanning signal G _{m + 2} , G ₃ ,...).

  The pulse widths of the enable signals ENB1, ENB2, ENB3, and ENB4 are about half of one horizontal period of the input video signal. Thus, by outputting the gate output pulse DY and the enable signals ENB1, ENB2, ENB3, and ENB4, one horizontal period for the light valve becomes half of the input video signal. Thus, one vertical period (one frame period) is divided into a first display period and a second display period, and screen scanning can be performed twice during one vertical period. In order to perform such scanning output, methods other than those shown in FIGS. 7 and 8 may be used, and changes may be made as appropriate within the category of design differences, such as changing the control method of the controller 61.

On the other hand, the data driver 201, based on the input image signal, and outputs positive voltage polarity is reversed to each other every horizontal period to the data lines S ₁ to S _n and the negative potential alternately. Accordingly, the polarity of the data signal _Sx side is inverted every horizontal period, while the gate pulse side is alternately output to two places on the screen separated by m scanning lines in the above order.

FIG. 9 shows the state of polarity change on the screen following the flow of time.
In FIG. 9, the vertical axis represents scanning lines constituting the scanning driver, and the horizontal axis represents time (unit: 1 horizontal period).
For example, in one horizontal period, a voltage having a positive potential is written in a pixel corresponding to the scanning signal G _4m . In the next one horizontal period, the positive potential voltage is written to the pixel corresponding to the scanning signal G _{m + 1} in which the positive potential voltage was written. Further in the next one horizontal period the potential of the negative polarity potential to the pixel corresponding to the scanning signal G ₁ a voltage of positive polarity potential is written is written. As described above, the write operation in which a plurality of pulse signals rising at different timings for each horizontal period is performed while skipping a part of the plurality of scanning lines is repeatedly executed while scanning for one vertical period. In the next one vertical period, the writing operation performed while skipping a part of the plurality of scanning lines is performed while scanning one vertical period in the same manner while the polarity opposite to that of the previous one vertical period is output. Repeatedly executed.

FIG. 10 is a diagram illustrating an image of a screen viewed at an instant of an arbitrary horizontal period.
As shown in FIG. 10, when attention is paid to a certain horizontal period on the screen, for example, pixels corresponding to the scanning signals G _{3 to} G _{m + 2} and G _{m + 3 to} G _4m are applied with a positive potential voltage (gradation signal). A pixel corresponding to the scanning signals G _{1 to} G ₂ is a region to which a negative potential voltage (gradation signal) is applied (hereinafter simply referred to as a negative polarity region). Become.
At this time, the positive polarity region (corresponding to the scanning signals G _{3 to} G _{m + 2} in FIG. 10) and the negative polarity region (corresponding to the scanning signals G _{1 to} G ₂ in FIG. 10) to which the voltage is applied in one vertical period The state is such that it is divided into three regions of a positive polarity region (corresponding to the scanning signals G _{m + 3 to} G _4m in FIG. 10) to which a voltage is applied in one vertical period. However, the positive polarity region (corresponding to the scanning signals G _{3 to} G _{m + 2} in FIG. 10) to which a voltage is applied in one vertical period is approximately ¼ of the entire region in which data is written. The screen is scrolled by one line every two horizontal periods from the upper side to the lower side of the screen, and the entire screen is scanned in one vertical period. Then, in the next one vertical period, the entire screen is scanned in one vertical period in the same manner while the polarity opposite to that of the previous one vertical period is output.

FIG. 11 is a diagram schematically showing a plurality of frame periods constituting an image displayed on the screen. In FIG. 11, since one frame period of the input image signal is substantially equal to the period of the vertical synchronization signal Vsync, the vertical axis is the screen image and the horizontal axis is time.
As shown in FIG. 11, one frame period of the input image signal is divided into a first display period and a second display period having a length different from that of the first display period. Specifically, the length of the first display period in one frame period is a 1/4 frame period of the input image signal, and the length of the second display period is 3/4 frame period of the input image signal. As described above, in this embodiment, the ratio of the first display period in one frame period is small, and the input image signal writing timing (speed) in the second display period in one frame period is fast. In FIG. 8, the first display period is a period from the time when the first gate output pulse DY1 is output to the time when the second gate output pulse DY2 is output, and the second display period is the second gate output. This is a period from the output of the pulse DY2 to the output of the first gate output DY1 in the next frame period.

Then, in the pixel where the liquid crystal device having the first frame period, every horizontal period for the data signals S ₁ to S _n around a common potential LCCOM, the polarity of the polarity of the potential and the negative polarity potential of the positive polarity potential Are applied alternately. Accordingly, a voltage having a positive polarity is applied to the pixel corresponding to the scanning line scanned in the first display period in the first frame period, and the pixel corresponding to the scanning line scanned in the second display period is applied to the pixel. A voltage having a negative polarity is applied.

  Similarly, in the second frame period after the first frame period, a voltage having a negative polarity polarity is applied to the pixel corresponding to the scanning line scanned in the first display period in the second frame period, so that the second display is performed. A voltage having a positive polarity is applied to the pixel corresponding to the scanning line scanned in the period. In the present embodiment, a frame period in which a positive potential and a negative potential pattern applied in consecutive first and second frame periods are set as one unit is repeatedly executed. That is, in the third frame period and the fourth frame period, as in the first frame period and the second frame period, the positive potential voltage is applied in the first display period of the third frame period, and the negative voltage is applied in the second display period. A negative potential voltage is applied during the first display period of the fourth frame period, and a positive potential voltage is applied during the second display period.

  In the present embodiment, as shown in FIG. 11, the application time of the positive potential and the application of the negative potential among the total time (the time indicated by the symbol B in the drawing) of the continuous first frame period and second frame period. Time is almost equal. That is, the total time of the application time of the positive potential in the first display period of the first frame period and the application time of the positive potential in the second display period of the second frame period, and the second display period of the first frame period The total time of the negative potential application time and the negative potential application time in the first display period of the second frame period are substantially equal. In addition, the sign of + (plus) and-(minus) in the figure indicates the polarity of the positive potential and the polarity of the negative potential, respectively.

According to the present embodiment, since the start timing of the second display period (the input image signal writing scan timing) is advanced compared to the start timing of the first display period, a desired gradation can be displayed as fast as possible. .
Further, according to the present embodiment, since the application time of the positive potential and the application time of the negative potential are substantially equal in the total time of the continuous first frame period and second frame period, the charge biased to the liquid crystal is The effect of accumulating is avoided, and the display is less likely to malfunction.
Furthermore, according to the present embodiment, since the positive and negative polarities can be reversed in the shortest two frames (the first frame period and the second frame period) in this configuration, charges biased in the liquid crystal accumulate. The impact can be minimized.

[Modification 1 of the first embodiment]
Hereinafter, this embodiment will be described with reference to FIG.
Since the basic configuration of the liquid crystal device is the same as that of the first embodiment, common constituent elements are denoted by the same reference numerals, and detailed description thereof is omitted.
FIG. 12 is a diagram schematically showing a plurality of frame periods constituting an image displayed on the screen.
As shown in FIG. 12, one frame period of the input image signal is divided into a first display period and a second display period having a length different from that of the first display period. Specifically, the length of the first display period is a ¼ frame period of the input image signal, and the length of the second display period is a ¾ frame period of the input image signal. Then, in the pixel where the liquid crystal device having the first frame period, every one vertical period (one frame period) for the data signal S ₁ to S _n, the polarity of the voltage of the positive polarity potential around a common potential LCCOM A voltage having a polarity of a negative potential is alternately applied. Therefore, in the present embodiment, the pixels corresponding to the scanning lines scanned in the first display period in the first frame period and the pixels corresponding to the scanning lines scanned in the second display period have the same positive polarity potential. A polar potential is applied.

  On the other hand, in the second frame period after the first frame period, the pixels corresponding to the scanning lines scanned in the first display period in the second frame period and the pixels corresponding to the scanning lines scanned in the second display period Is applied with a negative polarity potential. In the present embodiment, the frame period in which the positive potential potential and the negative potential pattern applied in the continuous first frame period and second frame period as described above are set as one unit is repeatedly executed.

  In addition, as shown in FIG. 12, the first display period and the second display period of the first frame period out of the total time (the time indicated by the symbol C in the figure) of the continuous first frame period and second frame period. The application time of the positive polarity potential is substantially equal to the application time of the negative potential in the first display period and the second display period of the second frame period.

According to the present embodiment, it is possible to obtain the same operational effects as those of the first embodiment. That is, since the start timing of the second display period is advanced, a desired gradation can be displayed as fast as possible. In addition, since the application time of the positive potential and the application time of the negative potential are substantially equal in the total time of the continuous first frame period and second frame period, the influence of accumulation of charges biased in the liquid crystal is avoided, The display is less prone to problems.
Furthermore, according to the present embodiment, since the positive and negative polarities can be reversed by the length of the first frame period and the second frame period that are the shortest in this configuration, the influence of accumulation of charges biased on the liquid crystal can be minimized. Can do.

[Modification 2 of the first embodiment]
Hereinafter, the present embodiment will be described with reference to FIG.

FIG. 13 is a diagram schematically showing a plurality of frame periods constituting an image displayed on the screen.
As shown in FIG. 13, one frame period is divided into a first display period and a second display period. In the present embodiment, after the scanning of the scanning signals G _{1 to} G _4m is completed in the first display period (after one vertical period), the scanning of the scanning signals G _{1 to} G _4m is started in the second display period. That is, in one frame period, after the enhancement conversion signal is written on the entire screen in the first display period, the adjustment conversion signal is written on the entire screen in the second display period.

Further, in the pixel where the liquid crystal device having the first frame period, every vertical period to the data signals S ₁ to S _n around a common potential LCCOM, the polarity of the polarity of the potential and the negative polarity potential of the positive polarity potential Are applied alternately. Therefore, in the present embodiment, the pixels corresponding to the scanning lines scanned in the first display period in the first frame period and the pixels corresponding to the scanning lines scanned in the second display period have the same positive polarity potential. A polar potential is applied.

  On the other hand, in the second frame period after the first frame period, the pixels corresponding to the scanning lines scanned in the first display period in the second frame period and the pixels corresponding to the scanning lines scanned in the second display period Is applied with a negative polarity potential. In the present embodiment, a frame period in which a positive potential and a negative potential pattern applied in consecutive first and second frame periods are set as one unit is repeatedly executed.

  As described above, in the present embodiment, as shown in FIG. 13, the first display of the first frame period out of the total time (the time indicated by the symbol C in the drawing) of the continuous first frame period and the second frame period. The application time of the positive potential in the period and the second display period is substantially equal to the application time of the negative potential in the first display period and the second display period in the second frame period.

  When the start timing of the second display period (the input image signal writing scan timing) is advanced compared to the start timing of the second display period as in this embodiment, the switching speed of the signal supplied to the scan line is simply set. In the method of increasing, the earlier the timing (writing scan timing of the input image signal), the more the signal switching speed has to be increased, and the load is applied to the circuit and at the same time it is not possible to secure the time to charge the pixels. Although it becomes difficult to display a desired gradation, the influence of accumulation of unbalanced charges on the liquid crystal can be minimized.

  Here, when this embodiment is compared with the first embodiment, in this embodiment, in any one frame period, the signal writing in the second display period is started from the signal writing start timing in the first display period. Although the time interval until the start timing is the same as that in the first embodiment, the scanning signal switching speed (the input image signal writing scanning timing) is increased. Therefore, as compared with the first embodiment, it is difficult to secure time for applying charges to the pixels. That is, in the first embodiment, even if the timing (input image signal writing scanning timing) is advanced, the signal switching speed does not have to be increased. Therefore, it is easy to secure time for applying charges to the pixels, and display of a desired gradation is facilitated. Therefore, in the first embodiment, the optical response characteristic of the liquid crystal light valve is appropriately compensated so that a desired gradation can be displayed as quickly as possible, and a display image can be displayed with less deterioration. This is different from the second modification of the first embodiment in that it is suitable for the first embodiment.

[Second Embodiment]
Hereinafter, the present embodiment will be described with reference to FIG.
Since the basic configuration of the liquid crystal device is the same as that of the first embodiment, common constituent elements are denoted by the same reference numerals, and detailed description thereof is omitted.

  14A to 14D are diagrams showing changes in the polarity of the screen in one frame period of the liquid crystal device. 14, (a) is the first display period of the first frame period, (b) is the second display period of the first frame period, (c) is the first display period of the second frame period, (d ) Indicates the second display period of the second frame period.

In the first display period of the first frame period shown in FIG. 14A, gate pulses are sequentially output to each of the scanning signals G _{1 to} G _4m , and the entire screen is scanned from the upper side to the lower side of the screen. The For example, as shown in FIG. 14 (a), the scanning signal when the gate pulse G ₂ is output, positive potential is applied to each of the data lines S ₁ to S _n around the common voltage LCCOM and negative potential Are alternately applied from the data driver 201. In particular, the data lines S ₁ a positive voltage potential is applied, the data line S ₂ voltage of the negative polarity potential is applied, in a similar manner for the other data line S ₃ to S _n A positive potential and a negative potential are applied alternately.

Subsequently, when the gate pulse is outputted to the scanning signal G _3, to each of the data lines S ₁ to S _n positive potential and the negative polarity voltage is sequentially applied alternately. At this time, as the polarity of the voltage applied to adjacent pixels is inverted, a voltage is applied to each of the data lines S ₁ to S _n. Therefore, the data lines S ₁ is applied a negative polarity potential, the data line S ₂ is positive potential is applied, likewise alternately be a positive voltage and a negative voltage to the other data line S ₃ ... S _n To be applied.

  Also, in the second display period shown in FIG. 14B, a voltage having the same polarity as the voltage applied to each pixel in the first display period is applied to each pixel. Thus, in the present embodiment, voltages having the same polarity are applied to corresponding pixels in the first display period and the second display period of the first frame period.

Next, each pixel in the first in the display period, when the gate pulse is outputted to the scanning signal G, the first frame period to the data lines S ₁ to S _n of the second frame period shown in FIG. 14 (c) A voltage having a polarity opposite to the voltage applied to is applied. Similarly, the polarity of the same voltage as the polarity of the voltage applied to each pixel of the first display period to the data lines S ₁ to S _n in the second display period shown in FIG. 14 (d) is applied. In this way, voltages having the same polarity are applied to each pixel in the first display period and the second display period of the second frame period.

  In the present embodiment, as shown in FIGS. 14A to 14D, the first frame period and the second frame period of the total time of the continuous first frame period and the second frame period, Application time of positive potential applied to pixels in one display period and second display period, and positive electrode applied to pixels in first display period and second display period of each of first frame period and second frame period The application time of the sexual potential is substantially equal. The positive and negative signs in the figure indicate the polarity of the positive potential and the polarity of the negative potential, respectively.

According to the present embodiment, it is possible to obtain the same operational effects as those of the first embodiment. That is, since the start timing of the second display period is advanced, a desired gradation can be displayed as fast as possible. In addition, since the application time of the positive potential and the application time of the negative potential are substantially equal in the total time of the continuous first frame period and second frame period, the influence of accumulation of charges biased in the liquid crystal is avoided, The display is less prone to problems.
Furthermore, according to the present embodiment, since the positive and negative polarities can be reversed by the length of the first frame period and the second frame period that are the shortest in this configuration, the influence of accumulation of charges biased on the liquid crystal can be minimized. Can do.

[Modification of Second Embodiment]
Next, a modification of the second embodiment will be described with reference to FIGS.
As will be described below, there is no problem even if the polarity checkered pattern or the driving with different polarities for each column is performed without paying attention to a certain pixel and deviating from the gist of the present invention.
15 to 17, (a) is the first display period of the first frame period, (b) is the second display period of the first frame period, and (c) is the first display period of the second frame period. , (D) shows the second display period of the second frame period.

FIGS. 15A to 15D are diagrams showing changes in the polarity of the screen in one frame period of the liquid crystal device.
In the first display period of the first frame shown in FIG. 15A, a voltage is applied to each pixel so that the polarity of the voltage between pixels adjacent to the X axis and the Y axis is inverted. In the second display period shown in FIG. 15B, the polarity of the voltage applied to each pixel in the first display period and the inverted voltage are applied to each corresponding pixel. In the first display period of the second frame shown in FIG. 15C, a voltage having the same polarity as the voltage applied to each pixel in the second display period of the first frame is applied to the corresponding pixel. In the second display period shown in FIG. 15D, a voltage that is the inverse of the polarity of the voltage applied to each pixel in the first display period is applied to each pixel.

FIGS. 16A to 16D are diagrams showing changes in the polarity of the screen in one frame period of the liquid crystal device. Note that the liquid crystal device shown in FIGS. 16A to 16D employs a line inversion driving method as a driving method.
In the first display period of the first frame period shown in FIG. 16A, gate pulses are sequentially output to each of the scanning signals G _{1 to} G _4m , and the entire screen is scanned from the upper side to the lower side of the screen. Is done. At this time, each of the data lines S ₁ to S _n, positive potential and the negative polarity potential around the common voltage LCCOM every horizontal period are alternately applied. In the second display period of the first frame shown in FIG. 16B, the same polarity voltage is alternately applied to each pixel every horizontal period as in the first display period. In the first display period of the second frame shown in FIG. 16C, a voltage inverted from the polarity of the voltage applied to each pixel in the first frame is applied by the line inversion method. In the second display period of the first frame shown in FIG. 16D, the same polarity voltage is applied to each pixel as in the first display period.

17A to 17D are diagrams showing changes in the polarity of the screen in one frame period of the liquid crystal device. Note that the liquid crystal device shown in FIGS. 17A to 17D employs a line inversion driving method as a driving method.
In the first display period of the first frame shown in FIG. 17A, a voltage having the same polarity pattern as that in the first display period of the first frame period shown in FIG. 16A is applied, as shown in FIG. In the second display period, a voltage whose polarity is reversed from that of the first display period is applied to each pixel. Then, in the first display period of the second frame period shown in FIG. 17C, a voltage having the same polarity pattern as that of the second display period of the first display period shown in FIG. 17A is applied, and FIG. In the second display period shown in (2), a voltage in which the polarity of the applied voltage is reversed from that in the first display period is applied to each pixel.

  In the present embodiment, as shown in FIGS. 15 to 17, the first frame period and the second frame period out of the total time (the time indicated by the sign in the drawing) of the continuous first frame period and second frame period. The application time of the positive potential in each of the first display period and the second display period, and the application time of the positive potential in each of the first display period and the second display period of the first frame period and the second frame period, Are approximately equal.

In the above-described first embodiment, the first modification of the first embodiment, the second modification, the second embodiment, and the modification of the second embodiment, any one of the continuous time periods of one frame period is arbitrary. In the pixel, the application time of the positive potential is substantially equal to the application time of the negative potential. On the other hand, in the total time of one continuous frame period such as four or six instead of two, the application time of the positive potential and the application time of the negative potential are substantially equal in any pixel. Thus, the gist of the present invention does not depart.
In addition, paying attention to one pixel as in the second embodiment and the modified example of the second embodiment described above, the application time of the positive potential and the negative electrode in any pixel in the total time of one continuous frame period. Since there are various combinations as long as the application time of the sexual potential is substantially equal, it is not limited to this configuration.

[Third Embodiment]
Hereinafter, the present embodiment will be described with reference to FIG.
Since the basic configuration of the liquid crystal device is the same as that of the first embodiment, common constituent elements are denoted by the same reference numerals, and detailed description thereof is omitted. In the following description, the “enhanced conversion signal” is a signal that causes the liquid crystal to respond faster than when the input image signal is supplied toward the transmittance determined by the input image signal. Is a signal for adjusting the response state of the liquid crystal after the enhancement conversion signal is input.

  As shown in FIG. 18, the liquid crystal device includes a synchronization extraction unit 40 that extracts a vertical / horizontal synchronization signal from an input image signal, and an operation control of each unit based on the vertical / horizontal synchronization signal extracted by the synchronization extraction unit 40. CPU 42 for performing the above, a frame frequency converting unit 44 for converting the frame frequency of the input image signal by two based on the control signal from the CPU 42, the ROM 38 storing the enhancement conversion parameter, and the enhancement conversion signal from the enhancement conversion parameter. An emphasis conversion unit 48 to be obtained, and a first frame memory 62 and a second frame memory 63 for writing / reading image signals are provided. Note that the first frame memory 62 and the second frame memory 63 in FIG. 18 are configured using the first frame memory 62 and the second frame memory 63 in FIG. 4, but other frames may be used as necessary. A configuration in which a memory is prepared may be used.

  The frame frequency conversion unit 44 reads an image signal twice at a double frame frequency based on a control signal from the CPU 42, and an image corresponding to one frame of the read input image signal is stored in the first frame memory 62 or the second frame memory. To 63. That is, one frame period of the input image signal is divided into a first display period and a second display period, and the same image data for one frame is read twice in one vertical display period (one frame period). Write to the memory 62 or the second frame memory 63. Note that the first frame memory 62 and the second frame memory 63 have a capacity capable of storing the enhancement conversion signal and the adjustment conversion signal.

  The ROM 38 stores parameters that allow the liquid crystal to respond faster than when the input image signal is supplied toward the transmittance determined by the image data (input image signal) in the current vertical display period within one vertical display period. Yes. These emphasis conversion parameters are obtained from measured values of optical response characteristics of the liquid crystal display panel 5.

  The emphasis conversion unit 48 reads out the image data before and after one vertical display period from the first frame memory 62 or the second frame memory 63, and refers to the ROM 38 from the read image data before and after the one vertical display period and performs the corresponding emphasis conversion. Read parameters. Then, using this emphasis conversion parameter, an emphasis conversion signal (writing gradation data) that causes the liquid crystal to have a transmittance determined by the current image data after one vertical display period has elapsed is output to the controller 61.

  Thus, the image data of the first display period in the Mth frame is subjected to enhancement conversion by the enhancement conversion unit 48 based on the comparison result with the image data of the second display period in the M−1th frame, and the controller 61 is output. On the other hand, for the image data in the second display period in the Mth frame, an adjustment conversion signal that adjusts the response state of the liquid crystal after the image data input in the first display period is output to the controller 61. The image data in the second display period in the Mth frame is output to the controller 61 as the same image data as the input image signal.

  Based on the control signal from the CPU 42, the controller 61 supplies the D / A converter 64 with the emphasis conversion signal subjected to the emphasis conversion in the first display period, and then the adjustment subjected to the adjustment conversion in the second display period. The converted signal is supplied to the D / A converter 64. The D / A converter 64 performs D / A conversion on the enhancement conversion signal and the adjustment conversion signal supplied from the controller 61 and supplies them to the data driver 201.

  According to this embodiment, the liquid crystal response speed is increased by applying the enhancement conversion signal so that the liquid crystal reaches the transmittance determined by the current frame image data after the first display period (¼ frame period of the input image signal) has elapsed. While accelerating (overshoot driving), the adjustment conversion signal is applied to the liquid crystal in the second display period (3/4 frame period of the input image signal). As a result, even if a liquid crystal response error due to overshoot drive occurs in the first display period, the response of the liquid crystal can be improved by the enhancement conversion signal, and adjustment for adjusting the response state of the liquid crystal after the enhancement conversion signal is input. A desired gradation can be adjusted by the conversion signal. Accordingly, the optical response characteristics of the liquid crystal device can be appropriately compensated so that a desired gradation can be displayed as fast as possible, and a display with little deterioration of the display image can be realized.

In the third embodiment, the input image signal is used as the adjustment conversion signal for adjusting the response state of the liquid crystal after the enhancement conversion signal is input. However, the present invention is not limited to this.
For example, a signal having a different intensity from the input image signal can be used as the adjustment conversion signal. In this case, the adjustment conversion signal for adjusting the response state of the liquid crystal after the input of the enhancement conversion signal is stored in the ROM 38 of FIG. 18 in association with the enhancement conversion signal and the adjustment conversion signal, and the enhancement conversion unit The configuration may be such that when the enhancement conversion signal is read out at 22, the adjustment conversion signal is called at the same time.

[Direct-view display device]
FIG. 19 is a schematic configuration diagram showing an example of a direct-view display device using the liquid crystal device (light modulation device) described in the above embodiment.
As shown in FIG. 19, a backlight 120 is disposed on one side of the liquid crystal device. The backlight 120 includes a plurality of light sources, and for example, a fluorescent tube, an LED, or a cold cathode tube is used. As described above, the direct-view display device of the present embodiment modulates the light from the backlight 120 and displays an image.
Moreover, it is also preferable that the backlight 120 is mainly composed of a light guide plate and a light source disposed on a side end surface of the light guide plate. Thereby, the light emitted from the light source enters the light guide plate through the side end surface of the light guide plate, propagates inside the light guide plate, and is emitted from the upper surface of the light guide plate to the liquid crystal device side.
According to this embodiment, an image can be visually recognized by the backlight 120 and the liquid crystal device that modulates the light emitted from the backlight 120. At this time, the liquid crystal device according to the present embodiment capable of displaying the desired gradation as fast as possible by appropriately compensating the optical response characteristics and realizing display with little deterioration of the display image is used for the light modulation device. Therefore, it is possible to realize a direct-view display device that can visually recognize a very excellent image.

[projector]
FIG. 20 is a schematic configuration diagram illustrating an example of a so-called three-plate projector using three liquid crystal devices (liquid crystal light valves) described in the above embodiment. In the figure, reference numeral 1100 denotes a light source, 1108 denotes a dichroic mirror, 1106 denotes a reflection mirror, 1122, 1123 and 1124 denote relay lenses, 100R, 100G and 100B denote liquid crystal light valves, 1112 denotes a cross dichroic prism, and 1114 denotes a projection lens system. .

  The light source 1100 includes a lamp 1102 such as a metal halide and a reflector 1101 that reflects light from the lamp 1102. The blue / green light reflecting dichroic mirror 1108 transmits 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 red light liquid crystal light valve 100R.

  On the other hand, of the color light reflected by the dichroic mirror 1108, green light is reflected by the dichroic mirror 1108 reflecting green light and is incident on the green liquid crystal light valve 100G. On the other hand, the blue light also passes through the second dichroic mirror 1108. 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 this, the blue light is incident on the blue light liquid crystal light valve 100B.

  The three color lights modulated by the light valves 100R, 100G, and 100B are incident on 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 as projection means, and the display image of the liquid crystal light valve is enlarged and displayed on the screen or the like. The screen may be a reflective screen that reflects light and displays an image, or a reflective screen that transmits light and displays an image. Further, the projector may be integrated with these screens.

  In general, the deterioration of the display image becomes more conspicuous as the screen becomes larger. Accordingly, in a projector that projects a liquid crystal light valve by enlarging a display image using a projection lens, the optical response characteristic is appropriately compensated so that a desired gradation can be displayed as quickly as possible, and the display image is deteriorated. It is very effective to use the liquid crystal light valve of the present embodiment capable of realizing a display with a small amount for a light modulation device.

It should be noted that the technical scope of the present invention is not limited to the above-described embodiments, and includes those in which various modifications are made to the above-described embodiments without departing from the spirit of the present invention.
For example, in the above-described embodiment and the modifications thereof, the description has been given of the transmissive liquid crystal device that transmits light. However, a reflective liquid crystal device that reflects light may be used. Further, the projection means is not limited to a lens system, and may be a mirror system using a curved mirror.
Finally, in the present embodiment, a liquid crystal device and a driving device in which the application time of the positive potential and the application time of the negative potential in the total time of two consecutive frame periods having two display periods are substantially equal. Although the example of the method was shown, the present invention is not limited to this, and other combinations are possible without departing from the spirit of the present invention. For example, FIG. 21 shows an example in which the application time of the positive potential and the application time of the negative potential in the total time of four consecutive frame periods having three display periods are substantially equal. In FIG. 21, the second display period and the third display period have the same length, but the first display period is shorter than the second display period and the third display period and has a different length. Then, by applying as shown in FIG. 21, the application time of the positive potential and the application time of the negative potential in the total time of the four consecutive frame periods are substantially equal.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal light valve (liquid crystal device), 3a, G ... Scan line, 6a, S ... Data line

Claims (8)

A liquid crystal device for displaying an image by supplying an input image signal to a plurality of pixels,
One frame period of the input image signal is divided into a plurality of display periods of s (s is a natural number of 2 or more), and at least one display period of the plurality of display periods of s is another. And a different length from the display period,
In the plurality of s display periods, a positive potential or a negative potential is applied to the pixel,
In a plurality of consecutive t (t is a natural number of 2 or more) frame periods, the total time of the application time of the positive potential to the pixel and the application time of the negative potential are substantially equal. A characteristic liquid crystal device. The plurality of s display periods includes a first display period and a second display period, and the plurality of consecutive t frame periods include a first frame period and a second frame period,
In the first display period of the first frame period, a positive potential or a negative potential is applied to the pixel,
In the second display period of the first frame period, a potential having a polarity different from the polarity applied to the pixel in the first display period of the first frame period is applied to the pixel.
In the first display period of the second frame period, a potential having a polarity different from that applied to the pixel in the first display period of the first frame period is applied to the pixel.
In the second display period of the second frame period, a potential having a polarity different from the polarity applied to the pixel in the second display period of the first frame period is applied to the pixel.
2. The application time of the positive potential to the pixel is substantially equal to the application time of the negative potential in the total time of the continuous first frame period and the second frame period. The liquid crystal device described. The plurality of s display periods includes a first display period and a second display period, and the plurality of consecutive t frame periods include a first frame period and a second frame period,
In the first display period of the first frame period, a positive potential or a negative potential is applied to the pixel,
In the second display period of the first frame period, a voltage having the same polarity as that applied to the pixel in the first display period of the first frame period is applied to the pixel.
In the first display period of the second frame period, a voltage having a polarity different from that applied to the pixel in the first display period of the first frame period is applied to the pixel.
In the second display period of the second frame, a voltage having a polarity different from that applied to the pixel in the second display period of the first frame period is applied to the pixel.
2. The application time of the positive potential to the pixel is substantially equal to the application time of the negative potential in the total time of the continuous first frame period and the second frame period. The liquid crystal device described.   An enhancement conversion signal that causes the liquid crystal to respond faster than when the input image signal is supplied toward the transmittance determined by the input image signal is supplied during the first display period, and the liquid crystal after the enhancement conversion signal is input 4. The liquid crystal device according to claim 1, wherein an adjustment conversion signal for adjusting a response state is supplied in the second display period. 5.   A plurality of data lines intersecting each other and a plurality of scanning lines, the pixels are connected to the data lines and the scanning lines, and the plurality of image signals whose polarity is inverted between a positive potential and a negative potential And supplying a plurality of pulse signals rising at different timings to each of the plurality of scanning lines while skipping a part of the plurality of scanning lines. The liquid crystal device according to claim 1, wherein the liquid crystal device is a liquid crystal device. A method of driving a liquid crystal device for displaying an image by supplying an input image signal to a plurality of pixels,
One frame period of the input image signal is divided into a plurality of display periods of s (s is a natural number of 2 or more), and at least one of the display periods of the s display periods is divided into other display periods. The length is different from the display period,
In the s display periods, a positive potential or a negative potential is applied to the pixel,
In a plurality of continuous t (t is a natural number of 2 or more) frame periods, the total time of application time of the positive potential to the pixel and the total time of application time of the negative potential are substantially equal. A driving method of a liquid crystal device characterized by the above. An illumination device, and a light modulation device that modulates light emitted from the illumination device,
6. A direct-view display device, wherein the light modulation device comprises the liquid crystal device according to any one of claims 1 to 5. An illumination device, a light modulation device that modulates light emitted from the illumination device, and a projection unit that enlarges and projects a display image of the light modulation device,
The projector according to claim 1, wherein the light modulation device includes the liquid crystal device according to claim 1.

Images