JP4581836B2 - Liquid crystal device, driving method of liquid crystal device, projector, and direct-view display device - Google Patents

Description

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

  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 3 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 some of the s display periods A positive potential is applied to the pixels in the display period, a negative potential is applied to the remaining pixels in the display period, and the application time of the positive potential to the pixels is applied in the one frame period. The total time is substantially equal to the total application time of the negative potential.

According to this configuration, since one frame period of the input image signal is divided into s display periods having different lengths, the start timing of the second and subsequent display periods (writing scan timing of the input image signal) Can be expedited. Thereby, a desired gradation can be displayed as fast as possible. On the other hand, when one frame period is divided into s display periods having different lengths, the application time of the positive potential is different from the application time of the negative potential, and therefore, charges biased in the liquid crystal accumulate in the one frame period. . On the other hand, in the present invention, the application time of the positive potential and the application time of the negative potential to the plurality of pixels are substantially equal in the total time of a plurality of consecutive one frame periods. The accumulation effect is avoided, and the display does not fail.
Furthermore, according to the present invention, the polarity inversion can be performed during one frame period because the application time of the positive potential and the application time of the negative potential are substantially equal in any pixel in one frame period. . Therefore, in the case of an input signal whose frequency of one frame is 60 Hz, for example, the polarity can be inverted at 60 Hz, so that display deterioration such as flickering is difficult to be seen when there is a slight difference due to positive and negative polarity, and display deterioration It can also be suppressed. In other words, if polarity inversion is performed for the total time of a plurality of frames, the polarity inversion frequency is lower than 60 Hz, and display degradation such as flickering is easily seen when there is a subtle difference due to positive and negative polarity. With the configuration of the present invention, a desired gradation can be displayed as fast as possible and the influence of display can be suppressed.

  In the liquid crystal device according to the aspect of the invention, the s display periods include a first display period, a second display period, and a third display period. In the first display period of the first frame period, the pixel includes a positive electrode. A positive polarity 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 second display period of the first frame period. A positive 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 third display period of the first frame period. A configuration in which a negative potential is applied is also preferable.

  In the liquid crystal device according to the aspect of the invention, the s display periods include a first display period, a second display period, and a third display period. In the first display period of the first frame period, the pixel includes a positive electrode. A positive polarity 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 first frame period. A potential or a negative potential is applied, and a positive potential 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 third display period of the first frame period. A configuration in which a negative potential is applied is also preferable.

According to this configuration, since one frame period of the input image signal is divided into the first display period, the second display period, and the third display period having different lengths, it is compared with the start timing of the second display period. Thus, the start timing of the second display period (writing scan timing of the input image signal) can be advanced. Thereby, a desired gradation can be displayed as fast as possible.
Further, when a positive (negative) polarity potential is applied to an arbitrary pixel of the liquid crystal device in the first display period in the first frame period, a positive (negative) polarity potential is applied in the second display period, Negative (positive) is applied in the third frame period. Therefore, in the total time of one frame period, since the application time of the positive potential and the application time of the negative potential are substantially equal in a plurality of pixels, the influence of accumulation of charges biased on the liquid crystal is avoided, and the display is troubled. Does not occur.
Further, as described above, the polarity inversion can be performed during one frame period because the application time of the positive potential and the application time of the negative potential are substantially equal in any pixel in one frame period. Therefore, in the case of an input signal whose frequency of one frame is 60 Hz, for example, the polarity can be inverted at 60 Hz, so that display deterioration such as flickering is difficult to be seen when there is a slight difference due to positive and negative polarity, and display deterioration It can also be suppressed.

  In the liquid crystal device according to the aspect of the invention, it is preferable that the first display period is shorter than a half time of the first frame period.

  According to this configuration, since the first display period is shorter than half the time of one frame period, the start timing of the second image display period (writing of the input image signal is compared with the start timing of the second image display period. By advancing the scanning timing, the desired gradation can be displayed as fast as possible.

  In the liquid crystal device of the present invention, the first display displays an enhanced conversion signal such that 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 that is supplied during a period and adjusts the response state of the liquid crystal after the emphasis conversion signal is input to the arbitrary pixel in the second display period. Furthermore, it is also preferable to supply a readjustment conversion signal for readjusting the response state of the liquid crystal after the adjustment conversion signal is input to the arbitrary pixel in the third display period.

According to this configuration, the liquid crystal can quickly respond toward the transmittance determined by the input image by the enhancement conversion signal, and the adjustment conversion signal and the adjustment conversion signal input for adjusting the response state of the liquid crystal after the enhancement conversion signal is input. It can be adjusted to a desired gradation by a readjustment conversion signal for readjusting the response state of the liquid crystal later.
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 image display period (writing scan timing of the input image signal) is advanced as compared with the start timing of the second image display period, the method of simply increasing the switching speed of the signal supplied to the scan line is The earlier the (input image signal writing scan timing) is, the faster the signal switching speed has to be and the load is applied to the circuit. Although display becomes difficult, according to this configuration, it is not necessary to increase the signal switching speed even if the timing (the 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 driving method of a liquid crystal device according to the present invention is 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 3 or more) for one frame period of the input image signal. Of the s display periods, at least one of the display periods has a different length from the other display periods, and some of the s display periods A positive potential is applied to the pixels in the display period, a negative potential is applied to the remaining pixels in the display period, and a positive potential is applied to the pixels in the one frame period. The total time of the time and the total time of application of the negative potential are substantially equal.
Also by the driving method of the liquid crystal device of the present invention, the same effects as the liquid crystal device of the present invention described above can be obtained.

  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. Therefore, in a projector that enlarges and projects a display image using a projection unit, the optical response characteristics are appropriately compensated so that a desired gradation can be displayed as fast as possible, and a display with little deterioration of the display image is realized. It is very effective to use the liquid crystal device of the present invention that can be used for a light modulation device.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
In this embodiment, an example of a liquid crystal light valve (liquid crystal device) used as a light modulation device of a projector (projection display device) will be described.
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.

(Overall configuration of liquid crystal light valve)
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 that forms the image display area of the liquid crystal light valve 1 in the present embodiment has a pixel electrode 9 and switching control for the pixel electrode 9. 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 data signals S1, S2,..., Sn to be written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. good.

  Further, the scanning line 3a is electrically connected to the gate of the TFT 30, and the scanning signals G1, G2,..., G4m are applied to each scanning line 3a in a pulsed manner at a predetermined timing while skipping as will be described later. It is configured. The pixel electrode 9 is electrically connected to the drain of the TFT 30, and the data signal S1, S2,..., Sn supplied from the data line 6a is obtained by turning on the TFT 30 as a switching element for a certain period. Write at a predetermined timing. Data signals S1, S2,..., Sn written to the liquid crystal via the pixel electrode 9 are held for a certain period with 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. Further, the controller 61 reads the input image signal DATA from the outside, supplies the read image signal to the first frame memory 62 or the second frame memory 63, and writes or reads the image signal.

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} 67 _(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 synchronizing signal Vsync is output once (during one vertical period), the driving circuit unit 60 synchronizes with the vertical synchronizing signal Vsync and outputs the gate output pulse DY to the shift register three times. Output. The first gate output pulse DY1 is a scan start start pulse in the first display period, the second gate output pulse DY2 is a scan start start pulse in the second display period, and the third gate output pulse DY3 is This is a start pulse for starting scanning in the third display period. The gate output pulse DY is shifted in the shift register 66 of the scan driver 104 in synchronization with the clock signal CLY that rises one pulse every horizontal period.

More specifically, as shown in FIG. 8 (range A in FIG. 7), enable signals ENB1, ENB2, ENB3, and ENB4 are input. Further, the interval between the gate output pulses output three times during one vertical period is separated by m scanning lines.
With the above operation, DY1 and DY2 are equivalent to m scanning lines, DY2 and DY3 are equivalent to m scanning lines, and DY3 and DY1 in the next vertical period are alternately separated into three places on the screen. Is output. That is, the gate output pulses are output at a ratio of 1: 1: 2 (m: m: 2m) on the screen. The pulse widths of the enable signals ENB1, ENB2, ENB3, and ENB4 are about 1/3 of one horizontal period of the input video signal. By outputting the gate output pulse DY and the enable signals ENB1, ENB2, ENB3, and ENB4 in this way, one horizontal period for the liquid crystal light valve becomes about 1/3 of the input video signal. Thus, one frame period is divided into a first display period, a second display period, and a third display period, and three screen scans are possible during one frame 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 polarity of the data signal Sx output from the data driver 201 is inverted in the order of the positive potential of two horizontal periods and the negative potential of one horizontal period thereafter with the common potential LCCOM as the center. Accordingly, the polarity of the data signal Sx side is reversed, and the gate pulse side is alternately output to three positions on the screen in the above order.

FIG. 9 shows the state of polarity change on the screen following the flow of time.
Note that the vertical axis in FIG. 9 is a scanning line constituting the scanning driver, and the horizontal axis is time (unit: 1 horizontal period).
For example, as shown in FIG. 9, the voltage of the negative potential is written to the pixel corresponding to the scanning signal G _4m in one horizontal period. In the next one horizontal period, the voltage of the positive potential is written to the pixel corresponding to the scanning signal G _{2m + 1} in which the voltage of the negative potential has been written. In the next one horizontal period, the positive potential is similarly written to the pixel corresponding to the scanning signal _{Gm + 1} in which the positive potential has been written. In the next one horizontal period, the voltage of the negative polarity potential is written into the pixel corresponding to the scanning signal G ₁ a voltage of positive polarity potential is written. As described above, the writing operation performed while skipping a part of the plurality of scanning lines with the plurality of pulse signals rising at different timings for each horizontal period is repeatedly executed while scanning the screen.

FIG. 10 is a diagram illustrating an image of a screen viewed at an instant of an arbitrary horizontal period.
On the screen, as shown in FIG. 10, when focusing on a certain horizontal period, for example, pixels corresponding to scanning signals G _{3 to} G _{m + 2} (first display period) and G _{m + 3 to} G _{2m + 2} (second display period) A region to which a positive potential voltage (grayscale signal) is applied (hereinafter simply referred to as a positive region), and scanning signals G _{1 to} G ₂ (third display period) and G _{2m + 3 to} G _4m (third display period). ) Is a region to which a negative potential voltage (gradation signal) is applied (hereinafter simply referred to as a negative region). In this way, the screen is divided into four regions, that is, a positive polarity region and a negative polarity region to which voltages having different polarities are applied (written). Each area scrolls the entire screen in one vertical period. However, all of the positive polarity regions are approximately ½ of the entire region where data is written, and all of the negative polarity regions are approximately ½ of the entire region where data is written. Further, as shown in FIG. 10, a plurality of scanning signals G _{3 to} G _{m + 2} and G _{m + 3 to} G _{2m + 2} to which a pulse signal that rises at a timing corresponding to the application time of the positive potential is adjacent to each other, and the negative potential A plurality of scanning signals G _{1 to} G ₂ and G _{2m + 3 to} G _4m to which a pulse signal that rises at a timing corresponding to the application time is supplied are adjacent to each other.

FIG. 10 is a diagram illustrating an image of a screen viewed at an instant of an arbitrary horizontal period.
On the screen, as shown in FIG. 10, when attention is paid to a certain horizontal period, for example, pixels corresponding to scanning lines G _{3 to} G _{m + 2} (first display period) and G _{m + 3 to} G _{2m + 2} (second display period) A region to which a positive potential voltage (grayscale signal) is applied (hereinafter simply referred to as a positive region), and scanning lines G _{1 to} G ₂ (third display period) and G _{2m + 3 to} G _4m (third display period). ) Is a region to which a negative potential voltage (gradation signal) is applied (hereinafter simply referred to as a negative region). In this way, the screen is divided into four regions, that is, a positive polarity region and a negative polarity region to which voltages having different polarities are applied (written). Each area scrolls the entire screen in one vertical period. However, all of the positive polarity regions are approximately ½ of the entire region where data is written, and all of the negative polarity regions are approximately ½ of the entire region where data is written. Further, as shown in FIG. 10, a plurality of scanning lines G _{3 to} G _{m + 2} and G _{m + 3 to} G _{2m + 2} to which a pulse signal that rises at a timing corresponding to the application time of the positive potential is adjacent to each other, and the negative potential A plurality of scanning lines G _{1 to} G ₂ and G _{2m + 3 to} G _4m to which a pulse signal that rises at a timing corresponding to the application time is supplied are adjacent to each other.

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, a second display period, and a third display period. Specifically, the length of the first display period in one frame period is a ¼ frame period of the input image signal, the length of the second display period is a ¼ frame period of the input image signal, and the third The length of the display period is 2/4 frame period of the input image signal, and the ratio of the time of the first display period, the second display period, and the third display period is approximately 1: 1: 2. . Further, the first display period is shorter than half the time of one frame period. 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 and the third display period in one frame period is the same. It's getting faster.

  Then, a positive potential is applied to the pixels of the liquid crystal light valve in the first frame period continuously for two horizontal periods centered on the common potential LCCOM, and then a negative potential having an inverted polarity is applied for one horizontal period. The Thereby, a voltage having a polarity of positive potential is applied to the pixels corresponding to the scanning lines scanned in the first display period and the second display period in the first frame period, and the scanning lines scanned in the third display period. A voltage having a negative polarity polarity is applied to the pixel corresponding to. In the present embodiment, the frame period with the positive polarity potential and the negative potential pattern applied in the first frame period as one unit is repeatedly executed.

  In the present embodiment, as shown in FIG. 11, the application time of the positive potential and the application time of the negative potential of the total time of the first display period, the second display period, and the third display period in one frame period are It is almost equal. That is, the total time of the application time of the positive potential in the first display period in the first frame period and the application time of the positive potential in the second display period, and the negative potential in the third display period of the first frame period. The total time with the application time 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. In the above description, the voltage applied during each display period may be reversed.

[Modification 1 of the first embodiment]
Hereinafter, this embodiment will be described with reference to FIG.
Since the basic configuration of the liquid crystal light valve 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. In FIG. 12, 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. 12, one frame period of the input image signal is divided into a first display period, a second display period, and a third display period. Specifically, the length of the first display period in one frame period is ¼ frame period of the input image signal, the length of the second display period is 2/4 frame period of the input image signal, The length of the display period is ¼ frame period of the input image signal, and the ratio of the time of the first display period, the second display period, and the third display period is approximately 1: 2: 1. . Further, the first display period is shorter than half the time of one frame period. 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 and the third display period in one frame period is the same. It's getting faster.

  Then, a positive potential or a negative potential is alternately applied to the pixels included in the liquid crystal light valve in the first frame period every horizontal period with the common potential LCCOM as a center. Accordingly, a voltage having a polarity of positive potential is applied to the pixels corresponding to the scanning lines scanned in the first display period and the third display period in the first frame period, and the scanning lines scanned in the second display period. A voltage having a negative polarity polarity is applied to the pixel corresponding to. In the present embodiment, the frame period with the positive polarity potential and the negative potential pattern applied in the first frame period as one unit is repeatedly executed.

  In the present embodiment, as shown in FIG. 12, the application time of the positive potential and the application time of the negative potential of the total time of the first display period, the second display period, and the third display period in one frame period are It is almost equal. That is, the total time of the application time of the positive potential in the first display period in the first frame period and the application time of the positive potential in the second display period, and the negative potential in the third display period of the first frame period. The total time with the application time 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. In the above description, the voltage applied during each display period may be reversed.

[Modification 2 of the first embodiment]
Hereinafter, the present embodiment will be described with reference to FIG.
In the present embodiment, a circuit configuration different from that of the first embodiment is used, and by switching the scanning signal speed (writing scan timing of the input image signal), the frame period configuration shown below is one frame. In any period, since the application time of the positive potential and the application time of the negative potential are substantially equal in any pixel, a configuration that does not depart from the spirit of the present invention can be realized. Since the basic configuration of the liquid crystal light valve 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. 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 of the input image signal is divided into a first display period, a second display period, and a third display period. Specifically, the length of the first display period in one frame period is a ¼ frame period of the input image signal, the length of the second display period is a ¼ frame period of the input image signal, and the third The length of the display period is 2/4 frame period of the input image signal, and the ratio of the time of the first display period, the second display period, and the third display period is approximately 1: 1: 2. . Further, the first display period is shorter than half the time of one frame period. 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 and the third display period in one frame period is the same. It's getting faster. The frame period with the positive potential and the negative potential pattern applied in the first frame period as one unit is repeatedly executed.

  Then, a positive potential is applied to the pixels of the liquid crystal light valve in the first frame period continuously for two vertical periods centering on the common potential LCCOM, and then a negative potential with the polarity reversed is applied for one vertical period. The

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. Then, after the scanning of the scanning signals G _{1 to} G _4m is finished in the second display period (after two vertical periods), the scanning of the scanning signals G _{1 to} G _4m is started in the third display period. That is, in one frame period, after image data is written on the entire screen in the first display period, image data is written on the entire screen in the second display period, and image data is written on the entire screen in the second display period. The image data is written again in the third display period.

  Further, as shown in FIG. 13, the application time of the positive potential and the application time of the negative potential are substantially equal in the total time of the first display period, the second display period, and the third display period in one frame period. ing. That is, the total time of the application time of the positive potential in the first display period in the first frame period and the application time of the positive potential in the second display period, and the negative potential in the third display period of the first frame period. The total time with the application time 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. In the above description, the voltage applied during each display period may be reversed.

  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. The time interval up to the start timing and the time interval from the signal write start timing in the second display period to the signal write start timing in the third display period are the same as in the first embodiment. The scanning signal switching speed (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 Modification 2 of the first embodiment in that it is suitable for the above.

[Second Embodiment]
Hereinafter, this embodiment will be described with reference to FIG.
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. Since the basic configuration of the liquid crystal light valve 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 14C are diagrams showing changes in the polarity of the screen in one frame period of the liquid crystal light valve. 14A shows the first display period of the first frame period, FIG. 14B shows the second display period of the first frame period, and FIG. 14C shows the third display period of the first frame period. In FIGS. 14A to 14C of the present embodiment, the first display period, the second display period, and the third display are described as an example illustrating an example of a method of arranging the polarities in the display area of the screen. The case where the ratio of time to period is approximately 1: 1: 2 will be described.

  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 G1 to G4m, and the entire screen is scanned from the upper side to the lower side of the screen. For example, as shown in FIG. 14A, when a gate pulse is output to the scanning signal G2, each of the data signals S1 to Sn has a positive potential or a negative potential centered on the common voltage LCCOM as a data driver. Applied alternately from 201. Specifically, a voltage having a positive potential is applied to the data signal S1, a voltage having a negative potential is applied to the data signal S2, and the positive potential and the other data signals S3. Negative polarity potentials are applied alternately.

  Subsequently, when a gate pulse is output as the scanning signal G3, a positive potential and a negative potential are alternately and sequentially applied to each of the data signals S1 to Sn. At this time, a voltage is applied to each of the data signals S1 to Sn so that the polarities of adjacent pixels are inverted. Therefore, a negative potential is applied to the data signal S1, a positive potential is applied to the data signal S2, and a positive voltage and a negative voltage are alternately applied to the other data signals S3. .

  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, in the third display period of the first frame period shown in FIG. 14C, when a gate pulse is output to the scanning line 3a, the data signals S1 to Sn are applied to each pixel in the first frame period. A voltage having a polarity opposite to that of the applied voltage is applied.

  According to the present embodiment, as shown in FIGS. 14A to 14C, among the total time of the first frame period, the total time of the first display period, the second display period, and the third display period. , The application time of the positive potential and the application time of the negative potential are 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.

[Modification of Second Embodiment]
Next, a modification of the second embodiment will be described.
Since the basic configuration of the liquid crystal light valve 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.

  FIGS. 15A to 15C are diagrams showing changes in the polarity of the screen in one frame period of the liquid crystal light valve. In the liquid crystal light valves shown in FIGS. 15A to 15C, the line inversion driving method is adopted as the driving method. 15A shows the first display period of the first frame period, FIG. 15B shows the second display period of the first frame period, and FIG. 15C shows the third display period of the first frame period. 15A to 15C, as an example illustrating an example of a method of arranging the polarities in the display area of the screen, the time between the first display period, the second display period, and the third display period. A case where the ratio is approximately 1: 1: 2 will be described.

In the first display period of the first frame period shown in FIG. 15A, 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 signals S ₁ to S _n, positive potential or negative potential around the common voltage LCCOM are alternately applied. In the second display period of the first frame shown in FIG. 15B, the same polarity voltage is alternately applied to each pixel as in the first display period. In the third display period of the first frame shown in FIG. 15C, a voltage that is inverted from the polarity of the voltage applied to each pixel in the first frame is applied by the line inversion method.

  According to the present embodiment, as shown in FIGS. 15A to 15C, among the total time of the first frame period, the total time of the first display period, the second display period, and the third display period. In FIG. 4, the application time of the positive potential and the application time of the negative potential are substantially equal. In the figure, the plus and minus signs indicate the polarity of the positive potential and the polarity of the negative potential, respectively.

In addition, in the first embodiment, the first modification, the second modification, the second embodiment, and the second embodiment, the one frame period is divided into three display periods. It is not limited to this. For example, one frame period is divided into four or more display periods, and at least one display period of the display periods has a length different from that of the other remaining display periods. In the pixel, as long as the application time of the positive potential and the application time of the negative potential are substantially equal, the gist of the present invention does not depart.
In the first embodiment, the first modification, the first modification 2, the second embodiment, and the second embodiment, the first display period, the second display period, and the third display period The time ratio is approximately 1: 1: 2 or 1: 2: 1. However, in any pixel, if the application time of the positive potential is substantially equal to the application time of the negative potential, the present invention is not limited to this configuration. Absent. For example, when one frame period is divided into four display periods as an example, the time ratio of the first display period, the second display period, the third display period, and the fourth display period is 1: 1: 1. : 3, a positive potential may be applied during the first display period, the second display period, and the third display period, and a negative potential may be applied during the fourth display period.
Furthermore, paying attention to one pixel as in the second embodiment and the modification of the second embodiment described above, the application time of the positive potential and the negative potential in any pixel during the total time of one frame period. If the application time is substantially equal, there are various combinations, and the present invention 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 light valve 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, and the “readjustment conversion signal” is a signal for adjusting the response state of the liquid crystal after the input of the adjustment conversion signal.

  As shown in FIG. 16, the liquid crystal light valve has a sync extractor 40 that extracts a vertical / horizontal sync signal from an input image signal, an operation of each part based on the vertical / horizontal sync signal extracted by the sync extractor 40, and the like. CPU 42 that performs control, frame frequency conversion unit 44 that converts the frame frequency of the input image signal to three times based on a control signal from CPU 42, ROM 38 that stores enhancement conversion parameters, and enhancement conversion signals from enhancement conversion parameters And a first frame memory 62 and a second frame memory 63 in which image signals are written / read out. Note that the first frame memory 62 and the second frame memory 63 in FIG. 16 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 at a triple frame frequency based on a control signal from the CPU 42, and an image for one frame of the read input image signal is stored in the first frame memory 62 or the second frame memory 63. Output to. The first frame memory 62 and the second frame memory 63 have a capacity capable of storing the enhancement conversion signal, the adjustment conversion signal, and the readjustment conversion signal.

  The ROM 38 has parameters and response states of the liquid crystal that can respond faster than the case where 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. The parameter etc. which adjusts are stored. The parameter stored in the ROM 38 may be an emphasis conversion parameter that allows the liquid crystal to respond to the target gradation of the image data in the current vertical display period within one vertical display period. 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 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. Next, 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. Next, for the image data in the third display period in the Mth frame, a readjustment conversion signal that adjusts the response state of the liquid crystal after the adjustment conversion signal is input in the second display period is output to the controller 61. The image data (adjustment conversion signal and readjustment conversion signal) in the second display period and the third 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. Thereafter, the readjustment variable signal that has undergone readjustment conversion in the third display period is supplied to the D / A converter 64. The D / A converter 64 performs D / A conversion on the enhancement conversion signal, adjustment conversion signal, and readjustment conversion signal supplied from the controller 61 and supplies the D / A converter 64 to the data driver 201.

  According to the present embodiment, the adjustment conversion signal and the adjustment conversion signal for adjusting the response state of the liquid crystal after the emphasis conversion signal is input, which allows the liquid crystal to respond quickly toward the transmittance determined by the input image by the emphasis conversion signal. Even if a liquid crystal response error due to overshoot drive occurs in the first display period due to the readjustment conversion signal that readjusts the response state of the liquid crystal after input, the response of the liquid crystal is improved by the enhancement conversion signal and the readjustment conversion signal. You can do it. Accordingly, it is possible to appropriately compensate the optical response characteristics of the liquid crystal light valve so that a desired gradation can be displayed as fast as possible, and to realize a display with little deterioration of the display image.

  In the third embodiment, the input image signal is used as the adjustment conversion signal and the readjustment 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. Absent. For example, as the adjustment conversion signal and the readjustment conversion signal, it is possible to use a signal having a different intensity from the input image signal. In this case, an 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. 16 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. Similarly, when the readjustment conversion signal is also a signal having a different intensity from the input image signal, the enhancement conversion signal, the adjustment conversion signal, and the readjustment conversion signal are stored in the ROM 38 of FIG. Alternatively, when the enhancement conversion unit 22 reads the enhancement conversion signal, the adjustment conversion signal may be called at the same time.

[projector]
FIG. 17 is a schematic configuration diagram showing an example of a so-called three-plate projector using three liquid crystal light valves of 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 which is a projection optical system, and the display image of the liquid crystal light valve is enlarged and displayed. 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. Further, the projection means is not limited to a lens system, and may be a mirror system using a curved mirror.

  In the projector having the above configuration, by using the liquid crystal light valve of the above embodiment, a projector having excellent display uniformity can be realized.

[Direct-view display device]
FIG. 18 is a schematic configuration diagram showing an example of a direct-view display device (liquid crystal projector) using a liquid crystal device having the same basic configuration as the liquid crystal light valve (light modulation device) described in the above embodiment.
As shown in FIG. 18, 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 and the liquid crystal device that modulates light emitted from the backlight. 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.

  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.

It is a top view which shows schematic structure of the liquid crystal light valve of 1st Embodiment. FIG. 2 is a cross-sectional view of the liquid crystal light valve taken along line H-H ′ in FIG. 1. FIG. 3 is an equivalent circuit diagram of a plurality of pixels in the display area of the liquid crystal light valve. 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; 3 is a timing chart for explaining the operation of the liquid crystal light valve. 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 light valve. It is a figure which shows the screen of the operation | movement written in the pixel of a liquid crystal light valve. It is a figure which shows the screen of the operation | movement written in the pixel of the liquid crystal light valve 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 light valve 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 light valve of 2nd Embodiment. It is a figure which shows the polarity change of the screen of 1 frame period of the liquid crystal light valve 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 light valve of 3rd Embodiment. It is sectional drawing which shows schematic structure of a projector. It is sectional drawing which shows schematic structure of a direct view type display apparatus.

Explanation of symbols

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

Claims (10)

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 s (s is a natural number of 3 or more) display periods, and at least one of the s display periods is included in another display period. With different lengths,
Among the s display periods, in some of the display periods, a positive potential is applied to the pixel, and in the remaining display periods, a negative potential is applied to the pixel.
In the one frame period, the total time of application time of the positive potential to the pixel is substantially equal to the total time of application time of the negative potential. The s display periods include a first display period, a second display period, and a third display 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 positive polarity potential or a negative polarity potential 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 third display period of the first frame period, a positive potential or a negative 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. The liquid crystal device according to claim 1. The s display periods include a first display period, a second display period, and a third display 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 positive or negative 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 third display period of the first frame period, a positive polarity potential or a negative polarity potential 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. The liquid crystal device according to claim 1.   4. The liquid crystal device according to claim 2, wherein the first display period is shorter than half the time of the first frame period. Supplying an enhanced conversion signal to the first display period such that 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;
5. The adjustment conversion signal for adjusting a response state of the liquid crystal after the enhancement conversion signal is input in the second display period is supplied to the plurality of pixels. 6. LCD device.   6. The liquid crystal device according to claim 5, wherein a readjustment conversion signal for readjusting the response state of the liquid crystal after the adjustment conversion signal is input is supplied to the plurality of pixels in the third display period.   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 s (s is a natural number of 3 or more) display periods, and at least one of the s display periods is different from the other display periods. Length,
Among the s display periods, in some of the display periods, a positive potential is applied to the pixels, and in the remaining display periods, a negative potential is applied to the pixels.
In the one frame period, the total time of application time of the positive potential to the pixel is substantially equal to the total time of application time of the negative potential. An illumination device, and a light modulation device that modulates light emitted from the illumination device,
A direct-view display device, wherein the light modulation device comprises the liquid crystal device according to claim 1. 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