JP2010026201A - Device and method of driving electro-optical device, electro-optical device, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the change in response characteristics of each pixel part due to a temperature change and the like in a driving device of an electro-optical device, which performs a subfield drive. <P>SOLUTION: A driving device (1) performs a subfield drive and applies a binary voltage to pixel parts in two or more subfields out of subfields into which one frame is divided. The driving device includes a compensation means which detects the change in response characteristics of pixel parts and applies the binary voltage while changing an application period so as to compensate for the change in response characteristics with respect to two or more subfields for change compensation adjacent to each other on a time base out of subfields. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a driving device and method for an electro-optical device such as a liquid crystal device that performs gradation control by subfield driving, and an electro-optical device including the driving device and an electronic apparatus such as a liquid crystal projector. About.

  In this type of driving device, one field is divided into a plurality of subfields on the time axis, and an on voltage or an off voltage is applied to each pixel portion in each subfield according to the gradation. That is, subfield driving is performed. Here, the response characteristics of each pixel unit in the electro-optical device, such as the response characteristics of the liquid crystal in the liquid crystal device, change according to the usage environment such as temperature during operation. Then, characteristics such as transmittance in each pixel portion change even if the on-voltage or off-voltage is the same. For this reason, conventionally, there is a technique for correcting a change in response characteristics by variably controlling a specific subfield (see Patent Document 1).

JP 2004-317681 A

  According to the above background art, in the case of a device that performs sub-field driving in a field sequential method in which an address period is provided independently of a display period in one frame, a change in response characteristics can be corrected to some extent.

  However, in the case of a device that performs subfield driving by a line sequential method in which an address period and a display period are integrally provided over one frame, there are the following problems. That is, when a specific subfield is changed, other subfields are affected by the change, and the subfield configuration of the entire frame is disturbed. Accordingly, it is difficult or impossible to cope with the above-mentioned background art. After all, there is a technical problem that abnormalities in gradation, luminance, color, etc. are caused by changes in response characteristics of liquid crystals caused by temperature changes and the like. is there. Thus, in the background art, it becomes difficult to correct the change in the response characteristic by the scanning method.

  The present invention has been made in view of, for example, the above-described problems, and in an electro-optical device driving device that performs sub-field driving, it is possible to reduce a change in response characteristics in each pixel unit due to a temperature change or the like. An object of the present invention is to provide a driving device and method for an electro-optical device, an electro-optical device including the driving device, and an electronic apparatus including the electro-optical device.

  In order to solve the above-described problem, a drive device for an electro-optical device according to the present invention is a drive device for an electro-optical device that drives a sub-field of an electro-optical device having a plurality of pixel portions arranged in an image display region, According to the gradation to be displayed for each of the plurality of pixel portions, for each of a plurality of subfields obtained by dividing one frame related to an image signal forming one image displayed in the image display area on the time axis. Driving means for applying an on-voltage or off-voltage to the plurality of pixel portions, detection means for detecting a response characteristic change of the plurality of pixel portions, and the preset sub-field among the plurality of subfields With respect to each of two or more change compensation subfields adjacent to each other on the time axis, the on-voltage or off-voltage while changing the application period so as to compensate for the detected response characteristic change. And a compensating means for applying.

  According to the driving device of the present invention, during the operation, the electro-optical device is driven in the subfield as follows. Here, in the “electro-optical device” according to the present invention, a plurality of pixel portions whose driving is controlled by, for example, pixel switching TFTs (thin film transistors) are arranged on a substrate, and each pixel portion is a pair of substrates. It has a structure in which an electro-optical material such as liquid crystal is sandwiched therebetween. In addition, a pixel electrode and a counter electrode are provided on each substrate so as to oppose each other. By applying a voltage between both electrodes, the orientation of the electro-optical material sandwiched between the substrates is controlled. In this way, the display device displays a display image based on the input image signal.

  That is, first, for example, by a driving unit including a scanning line driving circuit, a data line driving circuit, and the like, an on voltage or an off voltage corresponding to the gradation to be displayed for each of the plurality of pixel portions is provided for each of the subfields. It is applied to a plurality of pixel portions. Here, the “on voltage or off voltage” is a digital data signal or image signal used in subfield driving, and when this is applied to each pixel, digital driving, that is, subfield driving is performed.

  While the on-voltage or the off-voltage is applied in this way, the response characteristic change of the plurality of pixel portions in the image display area is detected by the detecting unit. Here, “response characteristic change” means that when an on-voltage and an off-voltage are applied to each pixel portion, characteristics such as optical characteristics change due to external factors such as temperature changes or internal factors. means. That is, the “response characteristic” means a characteristic such as an optical characteristic in each pixel portion including a minute portion of the electro-optical material. For example, in the case of an electro-optical material such as liquid crystal, the response characteristic change appears more or less due to the temperature change.

  When the response characteristic change is detected in this way, for example, the compensation means including a processor, a controller, a memory, or the like is turned on so as to compensate the response characteristic change detected by the detection means for each of the change compensation subfields. A voltage or an off-voltage is applied, and the application period is also changed. That is, the time width on the time axis of the change compensation subfield changes so as to compensate for the response characteristic change.

  Here, when the line sequential method is used as the driving device according to the present invention, for example, an address period and a display period are integrally provided over one frame. That is, in the line sequential method, when the period of a specific subfield is changed, it is necessary to adjust the period of one whole frame to be constant by appropriately changing the periods of other subfields. Therefore, in the present invention, when the period of the change compensation subfield is changed in accordance with the change in response characteristics, other subfield periods are also changed as necessary so that the period of the entire frame is constant. As a result, even when the line sequential method is used, it is possible to compensate for the response characteristic change by changing the period of the change compensation subfield.

  In this case, in particular, when the subfield configuration is changed, the ON / OFF driving period in one frame period increases / decreases, so that there is a considerable change in gradation expression. However, in practice, the number of subfields in one frame is set to be sufficiently large in accordance with the required number of gradations, device specifications, image signal specifications, etc., so the change in gradations due to the change in the subfield configuration described above. Is minute. Therefore, even if two or more change compensation subfields are set, there is a sufficient number of subfields, so that appropriate gradation expression is still possible.

  As described above, by providing the change compensation subfield, it is possible to compensate for the change in the response characteristic of the pixel portion by changing at least one of the applied voltage and the application period in the specific subfield. It is possible to prevent problems such as gradation abnormality, luminance abnormality, color abnormality and the like caused by. Thus, finally, high-quality image display is possible.

  As a result, even in the driving device of the electro-optical device driven by the subfield, it is possible to reduce the transmittance shift based on the response characteristic change of the pixel portion, and stable high-quality image display is possible.

  In one aspect of the driving apparatus according to the present invention, the compensation means is configured to perform the above-described compensation for each of the two or more change compensation subfields with respect to two pairs of the two or more change compensation subfields. The on-voltage or off-voltage is applied while changing the application period.

  According to this aspect, there are two pairs of two or more change compensation subfields. That is, two or more change compensation subfields adjacent to each other on the time axis are provided apart from each other on the time axis.

  According to the research of the present inventor, it has been found that a larger response characteristic change can be compensated for as the period occupied by the change compensation subfield in one frame increases. By providing two pairs of change compensation subfields in this way, a high-quality drive device that can compensate for a larger response characteristic change is realized by increasing the period occupied by the change compensation subfield in one frame. can do. In this mode, the period of four or more change compensation subfields is extended. Generally, however, since the number of subfields in one frame is sufficiently large, the change in gradation expression is very small. Therefore, appropriate gradation expression is still possible.

  In another aspect of the driving apparatus according to the present invention, the compensation means includes a first sub-field among three or more change compensation subfields continuous on the time axis as the two or more change compensation subfields. One of the on-voltage and off-voltage is applied to a field, and the on-voltage and off-voltage are applied to a second subfield adjacent to the first subfield among the three or more change compensation subfields. The other of the on-voltage and the off-voltage is applied to a third subfield adjacent to the second subfield among the three or more change compensation subfields.

  According to this aspect, out of a plurality of subfields, three or more subfields arranged in succession on the time axis are set as change compensation subfields. In this way, by providing the change compensation subfield, a smaller number of subfields can be formed as compared with the case where each change compensation subfield is formed in pairs as in the above-described embodiment. As a field, it becomes possible to compensate for a larger change in response characteristic. In other words, it is possible to set the switching time between the on-voltage and the off-voltage at any time in the three consecutive subfields, and the positions that can be taken by this switching position are extremely widened, so that the response characteristics change by that much. Can be compensated. As a result, higher quality image display is possible.

  In another aspect of the driving apparatus according to the present invention, the change compensation subfield is set in advance such that the total time of the plurality of subfields is maximized.

  According to this aspect, as the period occupied by the change compensation subfield in one frame increases, the change in the transmittance characteristic of the display unit can be suppressed with respect to a larger response characteristic change. In this case, a larger response characteristic change can be efficiently compensated.

  In another aspect of the driving apparatus according to the present invention, at least one of the change compensation subfields is shorter than a vertical scanning time for scanning one surface of the image display region.

  According to this aspect, since the change compensation subfield shorter than the vertical scan time for scanning one surface of the image display area is used, the minimum unit of the length of the change compensation subfield is the vertical scan time. In comparison, the response characteristic change can be finely compensated.

  It should be noted that at least one of the change compensation subfields may be longer than the time for continuously and sequentially scanning one surface of the image display area (ie, vertical scanning). For example, when the change compensation subfield is set in advance so that the total time of the plurality of subfields is maximized, the change compensation subfield becomes longer in this way. If the total time is large, a wider range of response characteristic changes can be compensated.

  In this aspect, the electro-optical device includes a plurality of scanning lines and a plurality of data lines that intersect each other at the intersections in the image display region, and the plurality of pixel units are arranged corresponding to the intersections. And the driving means alternately supplies a scanning signal to the scanning line for each of a plurality of areas in which the image display area is divided by dividing lines along the scanning line, and the image signal is supplied to the data. The difference between the time when the two scanning signals supplied to the line in synchronization with the scanning signal and supplied alternately for each of the plurality of regions as the scanning signal is supplied is shorter than the vertical scanning time. It may be configured.

  With this configuration, the difference between the times when the scanning lines are alternately scanned for a plurality of areas is shorter than the time for scanning one surface of the image display area (that is, the vertical scanning time). The subfield can be shorter than the vertical scanning time.

  In another aspect of the driving apparatus according to the present invention, the detection unit detects the temperature of the plurality of pixel units, and detects the detected temperature change as the response characteristic change.

  According to this aspect, the temperature of the plurality of pixel portions is first detected by the detecting means, and further, the detected temperature change is detected as a response characteristic change. Here, the “detecting means” in the present invention does not directly detect the response characteristic change of the pixel part, but may indirectly detect the response characteristic change of the pixel part by measuring the temperature of the pixel part. . For example, a temperature sensor is arranged so as to be in contact with an image display area composed of a pixel unit, and a temperature change of the pixel unit is measured, and based on this, a response characteristic change of the pixel unit is detected. Can do.

  Further, the temperature may be detected by a thermometer provided in a part of the plurality of pixel portions. That is, the temperatures of the plurality of pixel portions may be directly detected. Alternatively, the detection unit may detect the temperature with a thermometer provided in a case, a frame, a mounted part, or the like of the electro-optical device. That is, you may detect the temperature of a some pixel part indirectly.

  Furthermore, the detection means indirectly detects a response characteristic change in the pixel portion by detecting a parameter that depends on a temperature other than temperature or has a specific relationship, or a parameter that depends on a change in response characteristic or has a specific relationship. It may be detected. Further, changes in response characteristics in the pixel portion such as transmittance and luminance may be directly detected.

  In order to solve the above problems, a driving method of an electro-optical device according to the present invention is a driving method of an electro-optical device that performs sub-field driving of an electro-optical device having a plurality of pixel portions arranged in an image display region, According to the gradation to be displayed for each of the plurality of pixel portions, for each of a plurality of subfields obtained by dividing one frame related to an image signal forming one image displayed in the image display area on the time axis. A driving step of applying an on-voltage or an off-voltage to the plurality of pixel portions, a detection step of detecting a response characteristic change of the plurality of pixel portions, and the preset sub-field among the plurality of subfields With respect to each of two or more change compensation subfields adjacent to each other on the time axis, the on-voltage or off-voltage while changing the application period so as to compensate for the detected response characteristic change. And a compensation step of applying.

  According to the driving method of the present invention, as in the case of the above-described driving device of the present invention, it is possible to realize stable driving of the electro-optical device with respect to the response characteristic change.

  In the driving method of the present invention, various aspects similar to those of the above-described driving device of the present invention can be employed.

  In order to solve the above problems, the electro-optical device of the present invention includes the above-described electro-optical device driving device of the present invention (including various aspects thereof).

  According to the electro-optical device of the present invention, since the above-described driving device of the present invention is provided, high-quality image display is possible without depending on the response characteristic change in each pixel unit.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device of the present invention.

  According to the electronic apparatus according to the present invention, the liquid crystal device according to the present invention described above is included, so that a projection display device, a mobile phone, an electronic notebook, a word processor, a viewfinder type capable of high-quality display, or Various electronic devices such as a monitor direct-view video tape recorder, a workstation, a videophone, 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 present invention will be described with reference to the drawings.

<Liquid crystal device>
First, a configuration of a liquid crystal device will be described with reference to FIGS. 1 and 2 as an example of an electro-optical device including a driving device according to the present invention. FIG. 1 is a schematic plan view of a liquid crystal device when a TFT array substrate is viewed from the side of a counter substrate together with each component formed thereon, and FIG. 2 is a cross-sectional view taken along the line II-II ′ of FIG. is there.

  1 and 2, the liquid crystal device includes a TFT array substrate 10 and a counter substrate 20 disposed to face the TFT array substrate 10. 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 surrounded by an image display region 10a which is a typical example of the “image display region” of the present invention. They are bonded to each other through a sealing material 52 provided in the sealing area located.

  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.

  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.

  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 9 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.

<Electrical configuration of liquid crystal device>
Next, the electrical configuration and driving method of the driving device 1 of the liquid crystal device in the present embodiment will be described with reference to FIGS. FIG. 3 is a block diagram showing an electrical configuration of the driving device 1. FIG. 4 is a circuit diagram showing an electrical configuration of the display unit 100.

  In FIG. 3, the driving device 1 includes a driving circuit 500 that is an example of the “driving unit” of the present invention, a temperature sensor 510 that is an example of the “detecting unit” of the present invention, a display unit 100 that includes an image display region 10a, and A power supply circuit 700 for applying an LCCOM voltage to a counter electrode formed on the counter substrate 20 included in the display unit 100 is provided.

  Here, the driving circuit 500 includes a memory 520, a determination circuit 530, an image signal supply circuit 300, a timing control circuit 400, a selection circuit 550, a memory 560, a conversion circuit 570, a control signal processing circuit 630, a data line driving circuit 101, and A scanning line driving circuit 104 is provided.

  The temperature sensor 510 detects the temperature of the pixel portion of the image display region 10a during operation of the driving device, and inputs the change in the temperature to the determination circuit 530 as an electrical signal. The temperature sensor 510 is attached to, for example, a mounting case of a liquid crystal device or a dustproof glass provided in the liquid crystal device. In order to monitor the temperature of the liquid crystal layer, the temperature sensor 510 is preferably attached as close as possible to the pixel portion as long as the display operation is not hindered. The temperature quantified by the temperature sensor 510 may be, for example, Kelvin, Celsius (Celsius), Fahrenheit (Fahrenheit), thermodynamic temperature (absolute temperature), or the like. As will be described later, by measuring the temperature of the pixel portion with the temperature sensor 510 in this manner, the response characteristic change of the pixel portion is indirectly detected.

  The memory 520 stores a temperature value serving as a predetermined reference, and the determination circuit 530 evaluates the difference between the temperature value serving as the reference and the temperature detected by the temperature sensor 510.

  The timing control circuit 400 is configured to output various timing signals used in each unit. More specifically, a timing signal output unit that is a part of the timing control circuit 400 generates a dot clock that is a minimum unit clock and scans each pixel. Based on this dot clock, a Y clock signal is generated. CLY, inverted Y clock signal CLYinv, X clock signal CLX, inverted X clock signal XCLinv, Y start pulse DY, and X start pulse DX are generated. In particular, as described in detail later, by controlling the timing at which the Y start pulse DY is output to the scanning line driving circuit 104, the time width of the subfield in one frame can be changed.

  The control signal processing circuit 630 distributes various signals such as the X start pulse signal DX supplied from the timing control circuit 400 to the data line driving circuit 101 and the scanning line driving circuit 104. More specifically, the control signal processing circuit 630 supplies the Y clock signal CLY, the inverted Y clock signal CLYinv, and the Y start pulse DY to the scanning line driving circuit 104, and the X clock signal CLX, the inverted X clock signal XCLinv, And the X start pulse DX is supplied to the data line driving circuit 101.

  The image signal supply circuit 300 generates an image signal VID and supplies the image signal VID to the selection circuit 550. The power supply circuit 700 supplies a common power supply having a predetermined common potential LCCOM to the counter electrode 21 shown in FIG. In the present embodiment, the counter electrode 21 is formed on the lower side of the counter substrate 20 shown in FIG. 2 so as to face the plurality of pixel electrodes 9.

  Next, the electrical configuration of the display unit 100 will be described in detail.

  As shown in FIG. 4, the display unit 100 includes a plurality of pixel units 72 constituting the image display region 10a. The plurality of pixel portions 72 are formed in a matrix along the X direction and the Y direction in the image display region 10a. The pixel unit 72 includes a pixel electrode 9, a transistor element Tr, and a liquid crystal element 50a. The transistor element Tr is electrically connected to the data line 6 to which a digital image signal is supplied and the pixel electrode 9, and is used for pixel switching for switching control of the pixel electrode 9 when the liquid crystal device 1 is operated. TFT.

  The scanning line 3 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 3 in this order at a predetermined timing. It is configured to apply line-sequentially. The pixel electrode 9 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 of time, 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 9 are held for a certain period with the counter electrode formed on the counter substrate.

  The liquid crystal contained in the liquid crystal element 50a modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In this embodiment, since the image signal supplied to the display unit 100 is a digital signal that takes a binary potential of High or Low, an image signal having a High potential is supplied in the normally white mode. Then, the transmittance of incident light in the pixel portion 72 is reduced, and in the normally black mode, when an image signal having a high potential is supplied, the transmittance of incident light in the pixel portion 72 is increased. This makes it possible to emit light having a contrast corresponding to the image signal.

  In particular, during the operation of the driving device 1, high or low potentials defined by binary data constituting the code pattern of the digital image signal VID are supplied to the pixel electrode 9. In the image display area 10a, the voltage applied to the liquid crystal according to the potential difference between the potential of the pixel electrode 9 in each pixel portion 72 and the fixed potential LCCOM of the counter electrode 21, and the voltage applied to the pixel portion 72 in a plurality of gradation control periods. The gradation of each pixel can be controlled according to the combination of voltages. 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 9 and the counter electrode in order to prevent the image signal from leaking. Yes.

  In FIG. 3 again, the selection circuit 550 reads out the code pattern corresponding to the gradation of the image displayed on the display unit 100 from the memory 560 stored therein. The selection circuit 550 selects a code pattern corresponding to an image to be displayed on the display unit 100 based on the image signal VID, and supplies data related to the code pattern to the conversion circuit 570. Such a code pattern is composed of a high or low binary signal that defines a white display or a black display to be displayed on the pixel unit 72 in each of a plurality of gradation control periods, which constitutes a part of one field. Has been.

  Based on the data including the determination result supplied from the determination circuit 530, the conversion circuit 570 converts the data into a data signal Ds composed of binary values that defines each of the black display and the white display that can be displayed by the pixel unit 72. This is supplied to the line driving circuit 101. The data line driving circuit 101 supplies an image signal to each pixel unit 72 according to the scanning timing by the scanning line driving circuit 104. That is, the “on voltage or off voltage for subfield driving” according to the present invention is supplied from the conversion circuit 570 to the display unit 100 via the data line driving circuit 101 as a digital signal.

  Next, a subfield configuration in the data signal Ds supplied to the display unit 100 via the conversion circuit 570 and the data line driving circuit 101 will be described with reference to FIG. The data signal Ds converted into a digital signal for displaying an image to be displayed on the display unit 100 is a plurality of subfield periods SFi (i = 1,...) Obtained by dividing one field F along the time axis. ·, N: n is a natural number of 2 or more).

  FIG. 5 is a diagram showing a temporal correspondence relationship between the subfield configuration on the time axis in one frame of the data signal Ds and the scanning line driven by the scanning line driving circuit 104 in each subfield period. .

  Each subfield period is defined by the input timing of the start pulse DY that starts driving the scanning line. For example, in the first subfield SF1 shown in FIG. 5, all the scanning lines existing on the screen in the display unit after the corresponding start pulse DY1 is input and the driving of the scanning lines in the display unit are started. It is time to finish driving once. Also, as in SF3 and SF4, it is possible to change the period of the subfield by creating a waiting time between the end of the previous subfield period and the input of the next start pulse DY. It is.

  In the line-sequential driving apparatus as in the present embodiment, when there is only one scanning line that is driven at the same time, the next scanning line is scanned once in the sub-field until the scanning line finishes scanning the display unit once. A subfield cannot be started. Otherwise, different image signals cannot be supplied to the pixel portions in each row via the same data line. Therefore, it is necessary to ensure the period of one subfield longer than at least the time for scanning one scanning line (vertical scanning time) in the image display region 10a.

  Next, the operation and function of the compensation means of the present invention will be specifically described with reference to FIG.

  FIG. 6A is a schematic diagram showing a subfield configuration when eight subfields are provided in one frame in FIG. 5 (that is, when n = 8). In FIG. 6A, among the subfields SFi, SF6 and SF7 are used as the change compensation subfield VSFi. The period of the change compensation subfield VSFi is changed by the compensation means of the present invention. In FIG. 6, the periods of VSF6 and VSF7 are changed. Thus, the compensation means changes the period of the change compensation subfield by controlling the output timing of the Y start pulse DY from the timing control circuit 400.

  FIGS. 6B and 6C are schematic diagrams specifically showing an example in which the period of the change compensation subfield is changed. In this case, the period is changed by shifting the supply timing of the Y start pulse DY6 with respect to the change compensation subfields VSF6 and VSF7. For example, in FIG. 6B, the input timing of the Y start pulse DY6 is advanced as compared with FIG. 6A, thereby shortening the VSF6 period and changing the VSF7 period longer. In FIG. 6C, the input timing of the Y start pulse DY6 is delayed as compared with FIG. 6A, so that the period of VSF6 is lengthened while the period of VSF7 is shortened.

  Thus, in the line-sequential driving device as in this embodiment, the period of each subfield is changed according to the input timing of the start pulse DY. In particular, when a period is changed using one subfield as a change compensation subfield, it is necessary to change the period of the other subfield by the changed period. Therefore, it is necessary to provide at least two change compensation subfields. Conversely, by using two consecutive change compensation subfields, it is possible to perform change compensation by moving back and forth on the time axis only at the boundary located between them. There is no need to change the position of the other subfields.

  Here, with reference to FIG. 7, the effect of the present invention obtained by providing the change compensation subfield will be described in detail.

  FIG. 7 is a graph showing the temporal change in the light transmittance of the display unit 100 at two different temperatures. Here, the change in light transmittance is an example of the “response characteristic change” in the present invention. The solid line indicates the change in transmittance at a temperature of A ° C, and the dotted line indicates the change in transmittance at a temperature of B ° C (A ° C <B ° C).

  FIG. 7A shows a change in transmittance in a general driving device (that is, a driving device not provided with a change compensation subfield as in the present invention). As shown in FIG. 7A, it can be seen that when the temperature increases from A ° C. to B ° C., the line indicating the transmittance changes upward as a whole. This indicates that the characteristics of the liquid crystal element 50a in the display unit 100 change with a temperature change. On the other hand, FIG. 7B shows a change in transmittance when the subfield for change compensation in the present invention is used. In FIG. 7B, the deviation between the two graphs is smaller than in FIG. 7A. Therefore, by providing change compensation subfields and changing their periods, it is possible to obtain an effect of preventing a change in transmittance with respect to a change in temperature, that is, an abnormality in gradation and color due to a change in response characteristics. It becomes possible.

  As described above, 2SF continuous on the time axis is used as a subfield for change compensation, and by changing these periods, it is possible to prevent gradation abnormality and color abnormality in the image display unit due to response characteristic change. As a result, both the line-sequential method and the sub-field driven electro-optical device can be driven to compensate for the response characteristic change by changing the sub-field period.

  At this time, in particular, when the subfield configuration is changed (in FIG. 6, VSF6 and VSF7), the ON / OFF driving period in one frame period increases or decreases, so that there is a considerable change in gradation expression. In the present embodiment, for convenience, only eight subfields are provided in one frame, but in actuality, the number of subfields in one frame depends on the required number of gradations, device specifications, image signal specifications, and the like. Since a sufficiently large number is set, the change in gradation due to the change in the subfield configuration is very small. Therefore, even if the period of the change compensation subfield is changed for each temperature, an appropriate gradation display is finally performed.

  The change compensation subfield is preferably set in advance so that the total time of the plurality of subfields is maximized. According to the research of the present inventor, the change in the transmittance characteristic of the display unit can be suppressed with respect to a larger response characteristic change as the period occupied by the change compensation subfield in one frame becomes longer. Therefore, if the change compensation subfield is configured in this way, it is possible to efficiently compensate for a larger response characteristic change when the same number of change compensation subfields are provided.

  Specifically, it is preferable to provide a change compensation subfield as shown in FIG. In FIG. 8A, VSF6 and VSF7 are selected as variable period sub-fields. On the other hand, in FIG. 8B, VSF2 and VSF3 are selected as change compensation subfields. In FIG. 8A, the change compensation subfield has a higher wetting ratio than that in FIG. 8B, so that the transmittance can be compensated for a larger temperature change. Thus, if the change compensation subfield is selected by the subfield selection means, the effect of the present invention that the change in the transmittance characteristic with respect to the temperature change can be suppressed can be most effectively obtained.

  Next, a modified example of the drive device according to the present invention will be described.

<First Modification>
In the embodiment described above, the change compensation subfield is provided by selecting two consecutive subfields. As shown in FIG. 9, the change compensation subfield may be provided with a plurality of similar two consecutive subfields separated in time in one frame. In FIG. 9, by shifting the input timing of the Y start pulses DY3 and DY6, VSF3 and VSF4, and VSF6 and VSF7 are used as change compensation subfields.

  As described above, it has been found that as the period occupied by the change compensation subfield in one frame increases, a larger response characteristic change can be compensated. Therefore, if the subfield is formed in this way, the ratio of the change compensation subfield in one frame can be increased, so that it is possible to compensate for the change in transmittance characteristics in a wider temperature range.

Also in this modification, it is most preferable to provide the change compensation subfield so that the total period of the change compensation subfield in one frame is maximized.
<Second Modification>
Next, as shown in FIG. 10, change compensation subfield periods may be provided so as to continue in three or more subfield periods. In FIG. 10, the period of the change compensation subfields VSF5, VSF6, and VSF7 is changed by changing the input timing of the Y start pulses DY5 and DY6. In this way, by providing change compensation subfields, a smaller number of subfields can be used for change compensation than in the case where each change compensation subfield is formed in pairs as in the above-described embodiment. It is possible to compensate for a large response characteristic change only by using the subfield.
<Third Modification>
FIG. 11 is a block diagram illustrating an electrical configuration of a drive device for an electro-optical device according to a third modification.

  The controller 40 obtains the clock signal clk, the vertical scanning signal VS, the horizontal scanning signal HS, and the image signal D from the outside, transfers the start pulse DY, the scanning side transfer clock CLY, the enable signals ENBY1, ENBY2, and ENBX, and the data transfer. A clock CLX and a data signal Ds are generated. The enable signals ENBY1 and ENBY2 are data indicating a high level or a low level, and are used to select data to be output from the scanning line driving circuit 104 to the display panel 100. The enable signal ENBX is a pulse signal that determines the timing of starting data transfer to the data line driving circuit 101 and outputting data to the pixel 14c for each scanning line, and is a level transition (that is, rising edge) of the scanning side transfer clock CLY. And output in synchronization with the falling). The data transfer clock CLX is a signal that defines the timing for transferring data to the data line driving circuit 101. The data signal Ds is data corresponding to the image signal input to the controller 40, and is data indicating a high level or a low level for turning the pixel 14c on or off for each subfield period.

  The scanning line driving circuit 104 acquires a start pulse DY, a scanning side transfer clock CLY, and enable signals ENBY1 and ENBY2 from the controller 40, and scan signals G1, G2, and G3 for the scanning line 14a of the display panel 100. , ..., Gn is output.

  The data line driving circuit 101 acquires the enable signal ENBX, the data transfer clock CLX, and the data signal Ds from the controller 40, and the data signals d1, d2, d3,. dm is output.

  Here, the configuration and operation of the scanning line driving circuit 104 will be specifically described with reference to FIG. FIG. 12 is a diagram showing a schematic configuration of the scanning line driving circuit 104. The scanning line driving circuit 104 includes two shift registers 11aa and 11ab and AND circuits 11b1 to 11bn.

  As the scanning signals G1 to Gn / 2, the scanning transfer clock CLY and the start pulse DY are input, and the enable signal ENBY1 is set to a high level, so that the shift register 11aa sequentially drives the AND circuits 11b1 to 11bn / 2. Is output. As for the scanning signals Gn / 2 + 1 to Gn, the scanning transfer clock CLY and the start pulse DY are input, and the enable signal ENBY2 is set to the high level, so that the shift register 11ab sequentially drives the AND circuits 11bn / 2 + 1 to 11bn. Is output. In this way, the scanning signals G1 to Gn / 2 are output by the shift register 11aa to drive the scanning lines in the upper half of the image display area 10a, and the scanning signals Gn / 2 + 1 to Gn are changed by the shift register 11ab. By outputting, the scanning lines in the lower half of the image display area 10a are driven. The two shift registers 11aa and 11ab are driven so that the scanning lines G1 to Gn / 2 and the scanning lines Gn / 2 + 1 to Gn are alternately selected according to the scanning side transfer clock CLY and the start pulse DY. Therefore, in this modification, the scanning signals G1 to Gn are G1, Gn / 2 + 1, G2, Gn / 2 + 2, G3, Gn / 2 + 3,..., Gn / in accordance with the scanning transfer clock CLY and the start pulse DY. 2. Driven sequentially in the order of Gn (see FIG. 13).

  In this way, the image display area 10a is roughly divided into two areas, and one scanning line is displayed by alternately driving the scanning lines in each area while the other scanning line is in the address period. Can be assigned to. That is, by alternately scanning two scanning lines, the period of the change compensation subfield can be made shorter than one vertical scanning time.

  FIG. 14 is a schematic diagram showing a subfield configuration in one frame in the present modification. For each Y start pulse DY supplied to the scanning line driving circuit 104, two scanning lines alternately scan the screen. In FIG. 14, the scanning line by the start pulse input to the shift register (that is, shift register 11aa in FIG. 12) above the image display area 10a, and the shift register (that is, below the image display area 10a). In FIG. 12, the scanning lines by the start pulse input to the shift register 11ab) are indicated by a solid line and a one-dot chain line, respectively. Here, the period of the change compensation subfields VSF6 and VSF7 is changed by changing the supply timing of the Y start pulse DY6 back and forth on the time axis. By using such a scanning method, the change compensation subfield VSF6 is configured to be shorter than one vertical scanning time. Accordingly, the period of the change compensation subfield can be further reduced as compared with the other embodiments. As a result, the variable width of the period of the change compensation subfield can be greatly increased, and the response characteristic change can be compensated more finely.

<Electronic equipment>
Next, the case where the liquid crystal device which is the above-described electro-optical device is applied to various electronic devices will be described. FIG. 15 is a plan view showing a configuration example of the projector. Hereinafter, a projector using the liquid crystal device as a light valve will be described.

  As shown in FIG. 15, a projector 1100 includes a lamp unit 1102 made up 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 serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

  The configurations of the liquid crystal panels 1110R, 1110B, and 1110G are the same as those of the liquid crystal device described above, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit. The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In the dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Therefore, 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 liquid crystal panels 1110R, 1110B, and 1110G, the display image by the liquid crystal panel 1110G needs to be horizontally reversed with respect to the display images by the liquid crystal panels 1110R and 1110B.

  In addition, since light corresponding to each primary color of R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  In addition to the electronic device described with reference to FIG. 15, a mobile personal computer, a mobile phone, a liquid crystal television, a viewfinder type, a monitor direct view type video tape recorder, a car navigation device, a pager, an electronic device Examples include a notebook, a calculator, a word processor, a workstation, a videophone, a POS terminal, and a device equipped with a touch panel. Needless to say, the present invention can be applied to these various electronic devices.

  In addition to the liquid crystal devices described in the above embodiments, the present invention includes a reflective liquid crystal device (LCOS), a plasma display (PDP), a field emission display (FED, SED), an organic EL display, and a digital micromirror device. (DMD), electrophoresis apparatus and the like are also applicable.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and an electro-optical device with such a change, In addition, an electronic apparatus including the electro-optical device is also included in the technical scope of the present invention.

It is a top view which shows the whole structure of the electro-optical panel which concerns on this embodiment. It is the HH 'sectional view taken on the line of FIG. It is the block diagram which showed the electric constitution of the liquid crystal device which concerns on this embodiment. It is the circuit diagram which showed the electrical structure of the display part in the liquid crystal device which concerns on this embodiment. It is the schematic diagram which showed typically the structure of the general digital image signal. It is the schematic diagram which showed typically the structure of the image signal supplied to the liquid crystal device which concerns on this embodiment. FIG. 5 is a graph illustrating the relationship between the light transmittance of the liquid crystal device 1 and the gradation of the digitized image signal. It is the schematic diagram which showed typically the structure of the image signal supplied to the liquid crystal device which concerns on this embodiment. It is the schematic diagram which showed typically the structure of the image signal supplied to the liquid crystal device which concerns on a 1st modification. It is the schematic diagram which showed typically the structure of the image signal supplied to the liquid crystal device which concerns on a 2nd modification. It is the block diagram which showed the electric constitution of the liquid crystal device which concerns on a 3rd modification. It is a figure which shows schematic structure of the scanning-line drive circuit of the liquid crystal device which concerns on a 3rd modification. It is a timing chart figure of the control signal of the scanning line drive circuit of the liquid crystal device concerning the 3rd modification. It is the schematic diagram which showed typically the structure of the image signal supplied to the liquid crystal device which concerns on a 3rd modification. It is an example of the electronic device to which the electro-optical device is applied.

Explanation of symbols

  1 driving device, 40 controller, 101 data line driving circuit, 104 scanning line driving circuit, 11a shift register, 11b AND circuit, 100 display unit, 400 timing control circuit, 510 temperature sensor, 520 memory, 530 determination circuit, 550 selection circuit , 560 memory, 570 conversion circuit, 700 power supply circuit

Claims (10)

An electro-optical device driving apparatus that subfield-drives an electro-optical device having a plurality of pixel units arranged in an image display area,
For each of a plurality of subfields in which one frame related to an image signal forming one image displayed in the image display area is divided on the time axis, the gradation to be displayed for each of the plurality of pixel portions. Drive means for applying a corresponding on-voltage or off-voltage to the plurality of pixel units;
Detecting means for detecting a response characteristic change of the plurality of pixel units;
For each of two or more change compensation subfields adjacent to each other on the predetermined time axis among the plurality of subfields, the application period is changed so as to compensate for the detected response characteristic change. Compensating means for applying the on-voltage or off-voltage, and a driving device for an electro-optical device.   The compensation means is configured to change the on-voltage or the off-voltage while changing the application period for each of the two or more change compensation subfields with respect to the two pairs of the two or more change compensation subfields. The drive device of the electro-optical device according to claim 1, wherein: The compensation means includes
As the two or more change compensation subfields, one of the on voltage and the off voltage is applied to a first subfield among three or more change compensation subfields continuous on the time axis,
Applying the other of the on voltage and the off voltage to a second subfield adjacent to the first subfield among the three or more change compensation subfields;
The other of the ON voltage and the OFF voltage is applied to a third subfield adjacent to the second subfield among the three or more change compensation subfields. Drive device for electro-optical device.   4. The electro-optical device according to claim 1, wherein the change compensation subfield is set in advance such that a total time of the plurality of subfields is maximized. 5. Drive device. 5. The electro-optical device driving device according to claim 1, wherein at least one of the change compensation subfields is shorter than a vertical scanning time for scanning one surface of the image display region. . The electro-optical device includes a plurality of scanning lines and a plurality of data lines that intersect each other at the intersections in the image display area,
The plurality of pixel portions are arranged corresponding to the intersections,
The driving means supplies a scanning signal to the scanning line alternately for each of a plurality of areas obtained by dividing the image display area by a dividing line along the scanning line, and the image signal is supplied to the data line. In contrast, supply in synchronization with the scanning signal,
6. The drive of an electro-optical device according to claim 5, wherein a difference between times when two scanning signals supplied alternately for each of the plurality of regions as the scanning signal are supplied is shorter than the vertical scanning time. apparatus. The detection means detects the temperature of the plurality of pixel units, and detects the detected temperature change as the response characteristic change. 7. The drive device for an electro-optical device according to one item. An electro-optical device driving method for sub-field-driving an electro-optical device having a plurality of pixel units arranged in an image display region,
For each of a plurality of subfields in which one frame related to an image signal forming one image displayed in the image display area is divided on the time axis, the gradation to be displayed for each of the plurality of pixel portions. A driving step of applying a corresponding on-voltage or off-voltage to the plurality of pixel portions;
A detection step of detecting a change in response characteristics of the plurality of pixel portions;
For each of two or more change compensation subfields adjacent to each other on the predetermined time axis among the plurality of subfields, the application period is changed so as to compensate for the detected response characteristic change. And a compensation step of applying the on-voltage or the off-voltage.   An electro-optical device comprising the driving device according to claim 1.   An electronic apparatus comprising the electro-optical device according to claim 9.

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