JP5217813B2 - Liquid crystal device and electronic device - Google Patents

Description

  The present invention relates to, for example, a technical field of a liquid crystal device that employs time-division driving and an electronic apparatus such as a projector that includes such a liquid crystal device.

  In this type of liquid crystal device, a liquid crystal display device capable of reducing the influence of a lateral electric field generated between adjacent pixels and displaying a color image with high color reproducibility is disclosed (for example, see Patent Document 1). .)

JP 2000-330084 A

  However, when a moving image is displayed by the liquid crystal device, the alignment state of the liquid crystal is disturbed due to a lateral electric field generated between adjacent pixels. The time required to eliminate such disturbance of the orientation state is usually longer than the time for switching from one frame to another frame that arrives next to the one frame. Therefore, the liquid crystal state disturbance caused by the horizontal electric field causes tailing of an afterimage that may occur when a moving image is displayed, thereby degrading the display quality of the moving image.

  Therefore, the present invention has been made in view of the above problems and the like, and provides, for example, a liquid crystal device capable of displaying a moving image with high display quality, and an electronic apparatus such as a projector including such a liquid crystal device. The task is to do.

  In order to solve the above problems, a liquid crystal device according to a first aspect of the present invention includes a first pixel portion having a first pixel electrode formed in a display area on a substrate, and the first pixel electrode in the display area. And a second pixel portion formed adjacent to the first pixel portion and electrically connected to a common scanning line with the first pixel portion, and displayed in the display area In one frame, which is a period for displaying one unit image constituting a part of a moving image in the display area, black display is performed on the first pixel unit and white display is performed on the second pixel unit. And a driving circuit unit for driving the first pixel unit and the second pixel unit, and a first sub-frame which is a period of a part of the one frame, and half of the one frame. In the second subframe having the above time width, As the potential difference between the respective potentials of the serial first pixel electrode and the second pixel electrode is reduced, and a control means for controlling the drive circuit section.

  According to the liquid crystal device of the present invention, each of the first pixel portion and the second pixel portion is, for example, a part of a plurality of pixel portions provided in a matrix so as to constitute a display region on the substrate. . Each of the first pixel portion and the second pixel portion is electrically connected to a common scanning line, and is configured to be able to supply a common scanning signal via the scanning line. More specifically, for example, the operation of the pixel switching element included in each of the first pixel unit and the second pixel unit is performed by a scanning signal supplied via a scanning line that is common to these pixel units. Be controlled.

  The drive circuit unit includes, for example, a scan line drive circuit that performs switching control of each pixel unit via a scan line, and a data line drive circuit that supplies an image signal to each pixel unit. Such a drive circuit unit is configured to be able to supply an image signal to each pixel unit for each frame. According to the liquid crystal device of the present invention, unit images are sequentially displayed in the display area in each of a plurality of frames that are continuous along the time axis during the operation. A moving image is composed of unit images that are continuously displayed in this way. For example, the drive circuit unit supplies a digitized image signal to each pixel unit, and causes the image unit to display white or black on the pixel unit according to the potential. Here, “black display” refers to a state in which the light transmittance in the pixel portion is approximately 0%, and “white display” refers to a state in which the light transmittance in the pixel portion is approximately 100%. For example, the light source light such as a backlight is in a state of transmitting almost 100% through the liquid crystal layer. The drive circuit unit changes the total display time for displaying each of the black display and the white display in each pixel unit during the operation of the liquid crystal device, and changes the combination according to the unit image to be displayed. The brightness of each pixel unit is set.

  Here, the afterimage phenomenon that degrades the display quality of moving images is mainly caused by the disorder of the alignment state of the liquid crystal caused by the horizontal electric field generated between the pixel electrodes adjacent to each other in the period that occupies the second half of one frame. It is. Therefore, the control means is configured to receive the first pixel electrode in the second subframe that comes after the first subframe, which is a partial period of the one frame, and has a time width of half or more of the one frame. In addition, the driving circuit unit is controlled so that the potential difference between the respective potentials of the second pixel electrodes becomes small.

  Therefore, according to the liquid crystal device of the present invention, the potential difference between the potentials of the first pixel electrode and the second pixel electrode for each of the first pixel unit and the second pixel unit having different light transmittances. This can reduce the lateral electric field generated between the pixel electrodes. Therefore, according to the liquid crystal device of the present invention, it is possible to reduce the occurrence of disclination lines caused by afterimages such as tailing that may occur when a moving image is displayed, and display a high-quality moving image.

  In one aspect of the liquid crystal device according to the first aspect of the present invention, the control means is configured to perform the black display among the binary signals defining the black display and the white display in the second subframe. A corrected image signal having a potential between the potential of the corresponding black display signal and the potential of the white display signal corresponding to the white display among the binary signals is the first pixel electrode and the second pixel electrode. The drive circuit unit may be controlled so as to be supplied to at least one of the pixel electrodes.

  According to this aspect, the potential difference between the first pixel electrode and the second pixel electrode can be made smaller than the potential difference between the white display signal potential and the black display signal potential. Therefore, when a moving image is displayed, a lateral electric field generated due to a potential difference between the potential of the white display signal and the potential of the black display signal can be reduced, and an afterimage that can be generated when the moving image is displayed can be reduced.

  In order to solve the above problems, a liquid crystal device according to a second aspect of the present invention has a first pixel portion having a first pixel electrode formed in a display region on a substrate, and the first pixel electrode in the display region. And a second pixel portion formed adjacent to the first pixel portion and electrically connected to a common scanning line with the first pixel portion, and displayed in the display area In one frame, which is a period for displaying one unit image constituting a part of a moving image in the display area, black display is performed on the first pixel unit and white display is performed on the second pixel unit. The driving circuit unit for driving the first pixel unit and the second pixel unit and the first sub-frame which is a period of a part of the one frame, and more than half of the one frame In the second subframe having a time width of A resistance element that electrically connects the first pixel electrode and the second pixel electrode so that a potential difference between the potentials of the first pixel electrode and the second pixel electrode is reduced. Yes.

  According to the liquid crystal device of the present invention, the first pixel unit, the second pixel unit, and the drive circuit unit have the same configuration as the above-described liquid crystal device.

  The resistance element has, for example, a resistance value that is about two to three digits lower than the resistance value of the liquid crystal element in each of the first pixel portion and the second pixel portion, and the first pixel electrode and the first pixel electrode in the second frame. The first pixel electrode and the second pixel electrode are electrically connected to each other so that the potential difference between the two pixel electrodes is small. More specifically, for example, in the second frame, when an image signal corresponding to black display is supplied to the first pixel electrode and an image signal corresponding to white display is supplied to the second pixel electrode, the first pixel A current flows from one of the electrode electrodes and the second pixel electrode having a high potential to the other pixel electrode having a low potential, and the potential difference between the pixel electrodes is reduced by the amount of the current flowing.

  Therefore, according to the liquid crystal device according to the present invention, as in the liquid crystal device according to the first invention described above, the first pixel unit and the second pixel unit having different light transmittances are respectively used for the first pixel unit. A lateral electric field generated between the pixel electrodes due to the potential difference between the pixel electrode and the second pixel electrode can be reduced. Therefore, according to the liquid crystal device of the present invention, afterimages such as tailing that may occur when a moving image is displayed can be generated, and the occurrence of disclination lines can be reduced.

  In order to solve the above problems, an electronic apparatus according to a third aspect of the present invention includes the liquid crystal device according to each of the first and second aspects of the present invention described above.

  According to the electronic apparatus according to the present invention, since the liquid crystal device according to each of the first and second aspects of the present invention described above is provided, a projection type capable of displaying a high-quality moving image that hardly generates an afterimage. Various electronic devices such as a display device, a mobile phone, an electronic notebook, a word processor, a viewfinder type or a monitor direct-view type video tape recorder, a workstation, a video phone, a POS terminal, and a touch panel can be realized. In addition, as an electronic apparatus according to the present invention, for example, an electrophoretic device such as electronic paper can be realized.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

  Hereinafter, embodiments of the liquid crystal device according to the first and second inventions of the present invention and the electronic apparatus according to the third invention of the present invention will be described with reference to the drawings.

<First Embodiment>
A liquid crystal device 1 which is an embodiment of the liquid crystal device according to the first aspect of the present invention will be described with reference to FIGS.

<1-1: Configuration of Liquid Crystal Device>
First, the configuration of the liquid crystal device 1 according to the present embodiment will be described with reference to FIGS. 1 to 4. FIG. 1 is a block diagram showing an electrical configuration of the liquid crystal device 1 according to the present embodiment.

  In FIG. 1, the liquid crystal device 1 includes a display unit 200, a drive circuit unit 210, and a control circuit unit 220 which is an example of the “control unit” of the present invention, and is driven from the external circuit unit 230 during the operation. An image can be displayed on the display unit 200 in accordance with various signals supplied to the circuit unit 210.

  The display unit 200 includes a plurality of pixel units provided in a matrix on a substrate. For example, the display unit 200 is mounted on the electronic device as a part of the electronic device such as a projector, and a light source such as a backlight. The light emitted from the light is modulated by liquid crystal molecules and polarizing plates in each pixel portion. Such a voltage applied to the liquid crystal molecules, that is, a driving voltage for driving the liquid crystal molecules, depends on an image signal supplied to each pixel unit constituting the display unit 200 during the operation of the liquid crystal device 1. Is set. The liquid crystal device 1 may be used as a direct-view display that displays an image in an image display area of the display unit 200 including a plurality of pixel units, or projects display light emitted from the display unit 200 onto a screen. Thus, it may be used as a light valve of a projector capable of displaying an image on the screen.

  The drive circuit unit 210 includes a data line drive circuit that supplies an image signal to each of a plurality of pixel units constituting the display unit 200, and a scanning signal for switching on / off of each pixel unit via the scan line. 200 is a circuit unit configured to include various circuits such as a scanning line driving circuit to be supplied to 200. The drive circuit unit 210 is configured to be able to supply an image signal to each pixel unit for each frame when the display unit 200 displays a moving image. According to the liquid crystal device 1, when displaying a moving image, unit images are sequentially displayed in the image display area of the display unit 200 in each of a plurality of frames that are continuous along the time axis. A moving image is composed of unit images that are continuously displayed in this way. The drive circuit unit 210 supplies a digitized image signal to each pixel unit, and causes the pixel unit to display white or black on the image signal in accordance with the potential. Here, “black display” refers to a state in which the light transmittance in the pixel portion is approximately 0%, and “white display” refers to a state in which the light transmittance in the pixel portion is approximately 100%. For example, the light source light such as a backlight is in a state of transmitting almost 100% through the liquid crystal layer. The drive circuit unit 210 changes the total display time for displaying each of the black display and the white display in each pixel unit during the operation of the liquid crystal device 1, and changes the combination according to the unit image to be displayed. The brightness of each pixel unit is set.

  When the liquid crystal device 1 is operating, more specifically, when the moving image is displayed on the display unit 200, the control circuit unit 220 has an afterimage such as a tail in the image display area where the display unit 200 displays the moving image. The drive circuit unit 210 is controlled so that it does not remain, that is, a streak-like display defect such as disclination does not occur. The operation of the control circuit unit 220 will be described in detail when a driving method of the liquid crystal device described later is described.

  Next, a specific configuration of the liquid crystal device 1 will be described with reference to FIGS. 2 and 3. FIG. 2 is a schematic plan view of the liquid crystal device 1 as viewed from the counter substrate side together with the components formed on the TFT array substrate, and FIG. 3 is a cross-sectional view taken along the line III-III ′ of FIG. It is.

  2 and 3, the liquid crystal device 1 includes a TFT array substrate 10 and a counter substrate 20 disposed to face the TFT array substrate 100. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are positioned around an image display region 10a which is a typical example of the “display region” of the present invention. They are bonded to each other through a sealing material 52 provided in the sealing area.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. In the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance (inter-substrate gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed.

  A light-shielding frame light-shielding film 53 that defines the frame area of the image display area 10a is provided on the counter substrate 20 side in parallel with the inside of the seal area where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

  Of the peripheral regions located around the image display region 10 a, the data line driving circuit 101 and the external circuit connection terminal 102 are arranged on one side of the TFT array substrate 10 in the region located outside the seal region where the sealing material 52 is disposed. It is provided along. The scanning line driving circuit 104 is provided along one of the two sides adjacent to the one side so as to be covered with the frame light shielding film 53. The scanning line driving circuit 104 may be provided along two sides adjacent to one side of the TFT array substrate 10 provided with the data line driving circuit 101 and the external circuit connection terminal 102. In this case, the two scanning line driving circuits 104 are connected to each other by a plurality of wirings provided along the remaining one side of the TFT array substrate 10. Also. A control circuit unit 220 (not shown) is formed on the TFT array substrate 10 together with the data line driving circuit 101 and the scanning line driving circuit 104.

  Vertical conductive members 106 functioning as vertical conductive terminals between the two substrates are disposed at the four corners of the counter substrate 20. On the other hand, the TFT array substrate 10 is provided with vertical conduction terminals in a region facing these corner portions. Electrical conduction between the TFT array substrate 10 and the counter substrate 20 can be established by the vertical conduction terminals and the vertical conduction material 106.

  In FIG. 2, on the TFT array substrate 10, an alignment film is formed on the pixel electrode 9a after the pixel switching TFT, the scanning line, the data line and the like are formed. On the other hand, on the counter substrate 20, in addition to the counter electrode 21, a lattice-shaped or striped light-shielding film 23 and an alignment film are formed on the uppermost layer portion. The liquid crystal layer 50 is made of, for example, a liquid crystal in which one or several types of nematic liquid crystals are mixed, and takes a predetermined alignment state between the pair of alignment films.

  Next, the electrical configuration of the image display area 10a of the display unit 200 will be described in detail with reference to FIG. FIG. 4 is a circuit diagram illustrating a circuit configuration in the image display region 10a of the display unit 200 included in the liquid crystal device 1. The display unit 200 includes a plurality of pixel units 72 that form the image display region 10 a of the liquid crystal device 1. The plurality of pixel portions 72 are formed in a matrix in the image display area 10a along the X direction and the Y direction in FIG.

  The pixel unit 72 includes a pixel electrode 9a, a transistor element Tr, and a liquid crystal element 50a. The transistor element Tr is, for example, a pixel switching TFT. The transistor element Tr is electrically connected to the data line 6a to which the image signal converted into a digital signal is supplied and the pixel electrode 9a, and performs switching control of the pixel electrode 9a when the liquid crystal device 1 operates. The image 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. May be.

  The scanning line 3a is electrically connected to the gate of the transistor element Tr, and the liquid crystal device 1 applies the scanning signals G1, G2,..., Gm to the scanning line 3a in a pulse sequence in this order at a predetermined timing. It is configured to apply line-sequentially. The pixel electrode 9a is electrically connected to the drain of the transistor element Tr. By closing the switch of the transistor element Tr, which is a switching element, for a certain period, the image signals S1, S2,. ..., Sn is written at a predetermined timing. Image signals S1, S2,..., Sn written to the liquid crystal via the pixel electrode 9a are held for a certain period with the counter electrode formed on the counter substrate 20.

  Of the pixel electrodes 9a constituting part of each pixel portion 72, the pixel electrodes 9a are electrically connected to a common scanning line and arranged adjacent to each other along the X direction in FIG. Each is an example of the “first pixel electrode” and “second pixel electrode” of the present invention, and each of the pixel portions 72 including these pixel electrodes 9a is the “first pixel portion” of the present invention. And “second pixel portion”.

  The liquid crystal contained in the liquid crystal layer 50 modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In the present embodiment, the image signal supplied to the display unit 200 is a digital signal that takes a binary potential of High or Low corresponding to each of white display and black display. Such an image signal is supplied to each pixel electrode 9a when the liquid crystal device 1 is operated.

  Therefore, for example, if the liquid crystal device 1 is a liquid crystal device that displays an image in a normally white mode, when an image signal having a high potential is supplied, the transmittance of incident light in the pixel portion 72 decreases, and the pixel portion Displays black. If the liquid crystal device 1 is a liquid crystal device that displays an image in a normally black mode, when an image signal having a high potential is supplied, the transmittance of incident light in the pixel portion 72 increases, and the pixel portion White display. By driving the pixel unit 72 as described above, the liquid crystal device 1 can emit light having contrast according to the image signal. The storage capacitor 70 is electrically connected to the fixed potential line 300, and is added in parallel with the liquid crystal element 50a formed between the pixel electrode 9a and the counter electrode in order to prevent the image signal from leaking. Yes.

<1-2: Driving Method of Liquid Crystal Device>
Next, detailed operations of main components constituting the liquid crystal device 1 will be described with reference to FIGS. 5 to 8 while explaining a driving method of the liquid crystal device 1. FIG. 5 is a schematic diagram schematically showing a comparative example of white display and black display displayed in each of consecutive frames, and FIG. 6 shows white display and display displayed in each of consecutive frames. It is the schematic diagram which showed typically the horizontal electric field which generate | occur | produces in the comparative example of black display. FIG. 7 is a schematic diagram schematically showing white display and black display displayed in each of successive frames in the driving method of the liquid crystal device 1 according to the present embodiment, and FIG. 6 is a schematic diagram schematically showing a lateral electric field generated in white display and black display displayed in each of successive frames in the driving method of the liquid crystal device 1 according to FIG.

  In FIGS. 5 and 7, five pixel units 72 provided in a matrix in the image display region 10a are provided in the same row, and are continuously arranged in the row direction. White display and black display in the pixel portion are taken as an example, and in FIGS. 7 and 8, portions common to the portions shown in FIGS. 5 and 6 are denoted by common reference numerals.

  In the following description, among the digitized image signals, the potential of the high-level image signal is V0 + 5 (V), which is 5V higher than the potential V0 of the fixed potential line 300, and the potential of the low-level image signal is the fixed potential line. V0 is the same potential as the potential V0 of 300. In addition, in order to simplify the description of the driving method, for convenience, the potential V0 of the fixed potential line 300 is set to 0 (V), and the potential of the pixel electrode 9a to which the high-level image signal is supplied is set to 5 (V). And In addition, hereinafter, a case where the liquid crystal device 1 displays an image in a normally black mode will be described as an example.

  As shown in FIG. 5, when the liquid crystal device 1 displays a moving image, the first (N) th frame, the (N + 1) th frame, and the (N + 2) th frame that arrives sequentially along the time axis i) A low-level image signal is supplied from the pixel portion to the (i + 3) th pixel portion. Accordingly, in the Nth frame, in each of the (i) pixel portion to the (i + 3) pixel portion, the voltage applied to the liquid crystal layer 50 between the pixel electrode and the counter electrode facing the pixel electrode is 0 (V), and these four pixel portions perform black display. In parallel with this, a high-level image signal is supplied to the (i + 4) th pixel portion. Accordingly, in the Nth frame, in the (i + 4) th pixel portion, the voltage applied to the liquid crystal layer 50 between the pixel electrode and the counter electrode facing the pixel electrode is 5 (V). (I + 4) The pixel portion performs white display. Here, in the Nth frame, the pixel portions that are adjacent to each other and perform black display and white display are the (i + 3) th pixel portion and the (i + 4) th pixel portion.

  In the (N + 1) th frame that comes after the Nth frame, a low-level image signal is supplied from the (i) pixel portion to the (i + 2) pixel portion, and these pixel portions perform black display. In parallel with this, a high-level image signal is supplied to the (i + 3) th pixel portion and the (i + 4) th pixel portion, and white display is performed.

  In the (N + 2) th frame that comes after the (N + 1) th frame, a low level image signal is supplied to the (i) pixel portion and the (i + 1) th pixel portion, and these pixel portions perform black display. In parallel with this, a high-level image signal is supplied from the (i + 2) th pixel portion to the (i + 4) th pixel portion, and white display is performed.

  When a moving image consisting of unit images displayed in the image display area 10a from the Nth frame to the (N + 2) th frame is viewed, the boundary between white display and black display is the (i + 4) pixel portion and the (i + 3) pixel portion. Sequentially move from the boundary to the boundary between the (i + 2) th pixel portion and the (i + 1) th pixel portion.

  Here, with reference to FIG. 6, a lateral electric field generated between the pixel electrodes of the two pixel portions that are adjacent to each other and perform black display and white display will be described.

  As shown in FIG. 6, the liquid crystal device 1 includes a TFT array substrate 10, a counter substrate 20 disposed so as to face the TFT array substrate 10, pixel electrodes 9a1 and 9a2 provided between these substrates, and An alignment film 16, a liquid crystal layer 50, an alignment film 22, and a counter electrode 21 are provided. A voltage corresponding to the potential difference between the potentials of the pixel electrodes 9 a 1 and 9 a 2 adjacent to each other and the potential of the counter electrode 21 is applied to each pixel. By being applied to the liquid crystal layer 50 on the electrode, light modulation by the liquid crystal layer 50 is possible. The potentials of the pixel electrodes 9a1 and 9a2 that perform white display and black display, respectively, and are provided in each of the adjacent pixel portions are V0 and V0 + 5 (V), and the potential difference between these pixel electrodes Is 5 (V). Therefore, a lateral electric field E having an electric field strength corresponding to a voltage of 5 (V) acts between the pixel electrodes 9a1 and 9a2, and the alignment state of the liquid crystal molecules is disturbed. Such disturbance in the alignment state of the liquid crystal molecules causes disclination when a moving image is displayed in the image display area 10a, thereby degrading the display quality of the moving image. More specifically, as shown in FIG. 5, a striped afterimage 90 is generated in a region near the boundary between two pixel portions that perform white display and black display. Therefore, the liquid crystal device 1 reduces the striped afterimage 90 by a method of driving the liquid crystal device that can be executed with a configuration unique to the liquid crystal device 1 as described below.

  A driving method for driving the liquid crystal device 1 according to the present embodiment will be described with reference to FIGS. 7 and 8.

  As shown in FIG. 7 and FIG. 8, according to the liquid crystal device 1, the control circuit unit 220 includes each of an Nth frame, an N + 1th frame, and an N + 2th frame, each of which is an example of “1 frame” of the present invention. Pixel electrode 9a1 in the second sub-frame that comes after the first sub-frame, which is a part of the first sub-frame, and has a time width of half or more of each of the N-th, N + 1-th, and N + 2-th frames. Further, the afterimage 90 can be reduced by controlling the drive circuit unit 210 so that the potential difference between the respective potentials of the pixel electrode 9a2 becomes small.

  More specifically, the control circuit unit 220 corrects the potential of the image signal defining each of black display and white display in the second subframe of each of the Nth frame, the N + 1th frame, and the N + 2th frame. Thus, the data line driving circuit 101 is controlled so that the corrected image signal is output from the data line driving circuit 101, and each pixel unit is corrected in each of the first subframe and the second subframe in one frame. The scanning line driver circuit 104 is controlled so that a completed image signal can be supplied.

As shown in FIG. 7, the control circuit unit 220 supplies a black display signal, which is a corrected image signal corresponding to the black display in the second subframe of the Nth frame, to the (i + 3) th pixel unit. In addition, the drive circuit unit 210 is controlled. Similarly, in the second subframe in each of the (N + 1) th frame and the (N + 2) th frame, the operation of the drive circuit unit 210 under the control of the control circuit unit 220 causes the (i + 2) th pixel unit and the (i + 1) th frame. ) A black image signal that is a corrected image signal is supplied to each of the pixel portions. Here, the black image signal is, for example, a signal whose potential is increased as compared with the image signal before correction in which the potential of the pixel electrode is set to 0 V, and the potential is the potential of the low-level image signal. 1 (V) included in the range from 0 (V) to 5 (V) which is the potential of the image signal corresponding to white display.

  Therefore, as shown in FIG. 8, the potentials of the pixel electrodes 9a1 and 9a2 provided in the pixel portions that are adjacent to each other and perform white display and black display respectively occupy part of each frame. In the sub-frame, 1 (V) and 5 (V) are set, and the potential difference between these pixel electrodes is 4 (V) which is smaller than 5 (V). Therefore, the magnitude of the horizontal electric field E is 4 (V), which is smaller than the magnitude (5 (V)) of the horizontal electric field E that acts when the image signal is not corrected. Therefore, as shown in FIG. 7, the streaky afterimage 91 can be reduced compared to the afterimage 90.

  Thus, according to the liquid crystal device 1, display defects such as disclination lines caused by tailing that may occur when displaying a moving image can be reduced, and the display quality of the moving image can be improved.

(Modification)
Next, a modification of the driving method of the liquid crystal device that can be executed by the liquid crystal device 1 according to the first embodiment will be described with reference to FIG. FIG. 9 is a schematic diagram schematically showing white display and black display displayed in each of successive frames in the method of driving the liquid crystal device according to this example.

  As shown in FIG. 9, according to the liquid crystal device 1, in the second subframe of each frame, the control circuit unit 220 has low level and high level potentials that define the black display and the white display, respectively. Corrected image signals having a potential between the potential of the black display signal corresponding to the black display and the potential of the white display signal corresponding to the white display are output from the pixel electrode 9a1 and the pixel electrode 9a2. The drive circuit unit 210 is controlled so as to be supplied to at least one of the pixel electrodes.

  More specifically, in the second subframe of the Nth frame, a corrected image signal having a potential of 1 (V) is supplied to the (i + 3) th pixel portion, and 4 (V) of the (i + 4) th pixel portion. ) Is supplied. Here, for example, assuming that the pixel electrode of the (i + 3) th pixel portion is a pixel electrode 9a1, and the pixel electrode of the (i + 4) th pixel portion is a pixel electrode 9a2, a lateral electric field E acting between the pixel electrodes 9a1 and 9a2. Is 3 (V). Therefore, the lateral electric field E can be reduced as compared with the case where the image signal is not corrected. Similarly, in each of the second subframes of the (N + 1) th frame and the (N + 3) th frame, the (i + 2) th pixel unit and the (i + 3) th pixel unit which are adjacent to each other and perform black display and white display. ) The corrected image signal is supplied to each of the pixel unit, the (i + 1) th pixel unit, and the (i + 2) th pixel unit.

  Therefore, according to the driving method of the liquid crystal device according to the present example, since the lateral electric field acting between the adjacent pixel electrodes 9a1 and 9a2 can be reduced, the disorder of the alignment state of the liquid crystal molecules caused by the lateral electric field can be reduced. Display defects such as disclination lines can be reduced.

  In addition, if the corrected image signal is supplied to at least one of the pixel electrode 9a1 and the pixel electrode 9a2, a streaky afterimage due to a lateral electric field can be reduced.

Second Embodiment
Next, a liquid crystal device 500 as an embodiment of the liquid crystal device according to the second invention of the present invention will be described with reference to FIGS. The liquid crystal device 500 according to the present embodiment includes a resistance element that electrically connects the pixel electrodes to each other instead of the control circuit unit 220 provided in the liquid crystal device 1 according to the first embodiment. It is characterized by a point. Therefore, in the following, common reference numerals are assigned to parts common to the liquid crystal device 1, and detailed description thereof is omitted.

  The configuration of the liquid crystal device 500 according to the present embodiment will be described with reference to FIG. FIG. 10 is a circuit diagram illustrating a circuit configuration in an image display area of a display unit included in the liquid crystal device 500. FIG. 11 is a schematic diagram schematically showing a state in which the lateral electric field is relaxed.

  As shown in FIG. 10, the liquid crystal device 500 includes a resistance element 80 that electrically connects pixel electrodes 9a adjacent to each other. The resistance element 80 is, for example, a resistance layer formed on the TFT array substrate, and when the liquid crystal device 500 displays a moving image, the first period which is a part of one frame is the same as the liquid crystal device 1 described above. In a second sub-frame that arrives following one sub-frame and has a time width of more than half of the one-frame, the potential difference between the potentials of the two pixel electrodes adjacent to each other is reduced. Two pixel electrodes are electrically connected to each other.

  More specifically, as shown in FIG. 11A, when two pixel electrodes 9a1 and 9a2 adjacent to each other are not electrically connected to each other by the resistor element 80, the pixel electrode 9a1 displays black. , That is, an image signal having a potential of 0 (V) is supplied. In parallel with this, a white display signal corresponding to white display, that is, an image signal having a potential of 5 (V) is supplied to the pixel electrode 9a2. Therefore, when the pixel electrodes 9a1 and 9a2 are not electrically connected to each other by the resistance element 80, the electric field strength of the lateral electric field E acting between these pixel electrodes is large corresponding to a potential difference of 5 (V). That's it.

  On the other hand, as shown in FIG. 11B, when the pixel electrodes 9a1 and 9a2 are electrically connected to each other by the resistance element 80, the pixel electrodes 9a1 and 9a2 have black display signals corresponding to black display. When the white display signal corresponding to the white display is supplied, the current I flows between the pixel electrodes via the resistance element 80, and the potential difference between the pixel electrodes is reduced. More specifically, the potential of the pixel electrode 9a1 is increased from 0 (V) to 1 (V), and the potential of the pixel electrode 9a2 is decreased from 5 (V) to 4 (V). Therefore, the electric field strength of the lateral electric field E acting between these pixel electrodes is weakened to a magnitude corresponding to a potential difference of 3 (V), and the disorder of the alignment state of the liquid crystal molecules caused by the lateral electric field E is reduced. The

  Therefore, according to the liquid crystal device 500 according to the present embodiment, as in the liquid crystal device 1 according to the first embodiment described above, for each of the two pixel units having different light transmittances, Since the horizontal electric field generated due to the potential difference between the pixel electrodes of each pixel electrode can be reduced, afterimages such as tailing that can occur when moving images are displayed can be reduced, and the occurrence of disclination lines can be reduced. .

  The resistance value of the resistance element 80 that can reduce the magnitude of the lateral electric field E as described above may be a value that is two to three orders of magnitude smaller than the resistance value of the liquid crystal element that biases light. More specifically, for example, the resistance value of the resistance element may be about 10 MΩ, for example.

<Electronic equipment>
Next, a case where the liquid crystal device described above is applied to a projector which is an example of an electronic device will be described with reference to FIG. FIG. 12 is a plan view showing the configuration of the projector according to the present embodiment.

  In FIG. 12, a projector 1100 includes a lamp unit 1102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and light valves 1110R and 1110B corresponding to the respective primary colors. And 1110G. These three light valves 1110R, 1110B, and 1110G are each configured using a liquid crystal module including the liquid crystal device 1.

  In the light valves 1110R, 1110B, and 1110G, the liquid crystal device 1 is driven by R, G, and B primary color signals supplied from the image signal supply circuit 300, respectively. The light modulated by these liquid crystal devices 1 enters the dichroic prism 1112 from three directions. In this dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Accordingly, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

  Here, paying attention to the display images by the light valves 1110R, 1110B, and 1110G, the display image by the light valves 1110G needs to be horizontally reversed with respect to the display images by the light valves 1110R and 1110B.

  Since light corresponding to the primary colors R, G, and B is incident on the light valves 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  As described above, the projector 1100 includes the liquid crystal device 1 or 500 described above, and therefore, it is possible to reduce an afterimage generated when displaying a moving image and display a high-quality moving image.

1 is a block diagram illustrating an electrical configuration of a liquid crystal device according to a first embodiment. It is the top view which showed the specific structure of the liquid crystal device which concerns on 1st Embodiment. FIG. 3 is a cross-sectional view taken along the line III-III ′ of FIG. 2. FIG. 3 is a circuit diagram showing a plurality of pixel units constituting an image display area of the liquid crystal device according to the first embodiment. FIG. 6 is a schematic diagram schematically showing a comparative example of white display and black display displayed in each of consecutive frames during the operation of the liquid crystal device according to the first embodiment. FIG. 6 is a schematic diagram schematically showing a lateral electric field generated in a comparative example of white display and black display displayed in each of consecutive frames during operation of the liquid crystal device according to the first embodiment. In the driving method of the liquid crystal device 1 according to the first embodiment, it is a schematic view schematically showing white display and black display displayed in each of successive frames. FIG. 5 is a schematic diagram schematically showing a lateral electric field generated in white display and black display displayed in each of consecutive frames in the driving method of the liquid crystal device 1 according to the first embodiment. FIG. 6 is a schematic diagram schematically showing white display and black display displayed in each of successive frames in the method for driving a liquid crystal device according to a modification of the first embodiment. It is the circuit diagram which showed the circuit structure in the image display area | region of the display part which the liquid crystal device which concerns on 2nd Embodiment has. It is the schematic diagram which showed typically the state by which a horizontal electric field is relieve | moderated at the time of operation | movement of the liquid crystal device which concerns on 2nd Embodiment. It is a top view of the projector which is one Embodiment of the electronic device which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,500 ... Liquid crystal device, 72 ... Pixel part, 80 ... Resistive element, 200 ... Display part, 210 ... Drive circuit part, 220 ... Control circuit part, 9a, 9a1, 9a2 ... Pixel electrode

Claims (4)

A first pixel portion having a first pixel electrode formed on the front display region,
A second pixel unit which have a second pixel electrode formed to be adjacent to the first pixel electrode in the display area,
In the first sub-frame is a part of the period of one frame in one frame is a period for displaying a single position image that make up a part of a video to be displayed on the display area in the display area, the first luminance than the first display so as to perform the high second display, driving the first pixel portion and the second pixel unit to the second pixel part with to perform the first display to a pixel portion A drive circuit section;
In the second subframe with more than half the duration of the connection Ku previous SL 1 frame to the first sub-frame, the first pixel electrode and the potential difference is the first sub-frame between respective potentials of the second pixel electrode Control means for controlling the drive circuit unit so as to be smaller than the potential difference at
A liquid crystal device comprising: In the second sub-frame, the control means includes a black display signal potential corresponding to the black display among the binary signals defining the black display and the white display, and the white signal of the binary signal. The drive circuit so that a corrected image signal having a potential between the potential of the white display signal corresponding to display is supplied to at least one of the first pixel electrode and the second pixel electrode. The liquid crystal device according to claim 1, wherein the liquid crystal device is controlled. A first pixel portion having a first pixel electrode formed on the front display region,
A second pixel unit which have a second pixel electrode formed to be adjacent to the first pixel electrode in the display area,
In the first sub-frame is a part of the period of one frame in one frame is a period for displaying a single position image that make up a part of a video to be displayed on the display area in the display area, the first 1 pixel unit luminance than the first display to the second pixel part with to perform the first display driving the first pixel portion and said second pixel portion so as to perform the high second display to the drive A circuit section;
In the second subframe with more than half the duration of the connection Ku previous SL 1 frame to the first sub-frame, the first pixel electrode and the potential difference is the first sub-frame between respective potentials of the second pixel electrode A resistance element electrically connecting the first pixel electrode and the second pixel electrode so as to be smaller than a potential difference at
A liquid crystal device comprising: An electronic apparatus comprising the liquid crystal device according to any one of claims 1 to 3.

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