JP2005049775A - Electrooptical device, driving circuit and method, image signal generator and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce persistence of vision while increasing relative luminance while reducing in an electrooptical device such as a liquid crystal device or the like. <P>SOLUTION: The electrooptical device is provided with a plurality of pixel sections (10p) which are arranged in a planar manner in an image display region (10a) and driving means (101, 104, 160 and 170). The driving means drive the plurality of the pixel sections in an active matrix manner so that a display image is displayed in the image display region corresponding to image signals (Si) and an all over black image is superimposed and displayed on the display image in a time division manner with a time equivalent to two or more times of the frame period of the display image. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to, for example, an electro-optical device such as a current-driven liquid crystal device or an organic EL (Electro-Luminescence) device, a drive circuit provided in the electro-optical device, and an image signal generation device that provides an image signal to the electro-optical device And, for example, in the technical field of electronic devices including the electro-optical device, such as liquid crystal projectors and mobile phones.

  For example, in an electro-optical device that performs display in a hold mode, such as a current-driven liquid crystal device or an organic EL device, compared to a display device that performs display in an impulse mode such as a CRT (Cathode Ray Tube), Visual afterimage is noticeable. For this reason, in order to reduce such an afterimage, there is a technique for artificially setting an impulse mode by modifying the drive waveform for driving the electro-optical device (see Patent Documents 1 and 2). Specifically, for example, a solid black image is displayed over the entire image display area between the display period of one frame and the display period of the next frame in the image signal, thereby reducing afterimages during moving image display.

Japanese Patent Laid-Open No. 9-127717 JP-A-11-109921

  However, according to the technique of inserting a solid black image between frames as in the above-described pseudo impulse mode display, the current display type liquid crystal panel and the organic EL panel, in particular, have the entire image display area black. It takes a considerable amount of time to get into the state. For this reason, the luminance perceived by human vision as a time average value including a black image is lowered according to the display cycle of the black image. In addition, when inserting a black image, if the insertion time is not long, the effect of setting the pseudo impulse mode does not appear. Therefore, until the entire area of the current-driven liquid crystal panel and the organic EL panel is made black Even if the time is shortened, the insertion of a solid black image between frames still has a technical problem that the luminance must be sacrificed in order to effectively reduce the afterimage.

  The present invention has been made in view of the above problems, for example. An electro-optical device capable of reducing afterimage while relatively increasing luminance, a drive circuit and a method provided in the electro-optical device, It is an object of the present invention to provide an image signal generation device that provides an image signal to an electro-optical device, and various electronic apparatuses including the electro-optical device.

  In order to solve the above problems, the electro-optical device of the present invention is configured so that a plurality of pixel units arranged in a plane in an image display region and a display image corresponding to an image signal are displayed in the image display region and the display Drive means for driving the plurality of pixel portions in an active matrix so that a solid black image is displayed on the display image in a time-division manner over a time corresponding to a multiple of the frame period of the image.

  According to the electro-optical device of the present invention, during the operation, the plurality of pixel units are driven by the driving unit, and a display image corresponding to the image signal is displayed in the image display region. The pixel unit according to the present invention includes, for example, a pixel unit such as a current-driven liquid crystal panel or an organic EL panel, and performs display in a hold mode. However, not only the current drive type but also a voltage drive type may be used.

  In particular, during such driving, a solid black image is superimposed and displayed on the display image in a time-division manner over a time corresponding to a multiple of the frame period of the display image. Hereinafter, this “plurality” is appropriately referred to as “N times” (where N is a natural number). In other words, a solid black image is completed in a time-division manner in the entire display image in a time corresponding to N times of the frame period, or a frame image is displayed N times in a time-division manner so that a solid image is obtained in a time-division manner over the entire display image. A black image will be completed.

  The “black image” according to the present invention is not only the darkest image or black image that can be displayed in the image display area, but also an image darker than the average brightness as long as the afterimage can be reduced, such as dark gray or gray. If it is good. Furthermore, “solid” according to the present invention refers to a uniform state that has no particular meaning and is not related to a display image such as a moving image or a still image that means some content in addition to a complete solid. As long as it can be reduced, there is no problem even if there are some spots or patterns.

  Specifically, in the first frame period, for example, only a part of the image display area obtained by dividing the image display area or the effective image display area equally or evenly into 1 / N on the display image. For example, a black image is displayed as a black line or the like, and in the second frame period, a black image is displayed as a black line or the like only on another part of the image display area on the display image. Then, such a display operation is repeated, and in the Nth frame period, a black image is displayed as a black line or the like on only the remaining part of the image display area on the display image. As a result, a solid black image is superimposed and displayed on the display image in a time-division manner as a sum of a plurality of black lines, for example, taking a time corresponding to N frame periods. Then, for example, a black image portion displayed as a black line or the like only partially in a short time, such as 1/60 seconds as a frame period, is not recognized by human vision in any frame period. However, of the time corresponding to N frame periods, a black image is displayed on each pixel portion over one frame period in any frame period. That is, as compared with the case where a black image is displayed between frames as in the background art described above, each pixel unit that performs black display can be brought into a black state with a much longer time margin. it can. Therefore, as for each pixel portion, the afterimage can be significantly reduced due to the presence of an image displayed well in black. Such an afterimage reduction action takes time corresponding to N frame periods to reach the entire display image, that is, the entire image display area or effective image display area. As a result, the afterimage is reduced extremely effectively.

  Moreover, since the luminance is only reduced at a rate of 1 / N for each pixel portion, if N is set according to the required luminance, the reduction in luminance is hardly visually noticeable. Can be.

  As a result, according to the electro-optical device of the present invention, it is possible to reduce the afterimage while suppressing the decrease in luminance or relatively increasing the luminance. In particular, in the case of a current-driven liquid crystal device or an organic EL device, it takes time to make each pixel portion into a black state, and it is difficult to obtain a good black state in a short time between frames. . However, since the frame period itself is used to make the black state as in the present invention, a good black state can be obtained even in the case of a current-driven liquid crystal device or an organic EL device, and an afterimage is appropriately obtained. Can be reduced. Even when a hold mode display operation in which an afterimage is relatively remarkable is performed, that is, in the case of a liquid crystal device or the like, the afterimage can be reduced.

  Further, as a method of inserting a black image into a display image, the driving means includes a plurality of such that a portion where the black image is superimposed and displayed in the display image is thinned out for each frame period, and the thinned portion is replaced with a black image. The pixel portion may be configured to be driven in an active matrix. Alternatively, the driving unit may drive the plurality of pixel units in an active matrix so as to divide a portion of the display image where the black image is superimposed and to insert the black image at the boundary every frame period. It may be configured. In any case, an effect unique to the present invention that suppresses a decrease in luminance while reducing the afterimage as described above can be obtained.

  In addition, the black image may be continuously inserted into all the continuous frame images constituting the display image. Alternatively, it may be inserted intermittently, such as every other frame image or every other frame image. In any case, a single solid black image may be displayed in a time-division manner over the entire display image in a cycle of N frames. In addition, when displaying a single solid black image in a time-sharing manner, it is sufficient to display a black image only once for any one pixel portion, but some pixel portions overlap or Even if the black image is displayed twice or more times, a corresponding effect can be obtained. Further, it is desirable to display such a black image for all the pixel portions constituting the image display area or the effective image display area in order to maximize the effect of reducing the afterimage. Even if a black image is not displayed for the afterimage reduction as described above for a plurality of pixel portions that are located in a part of the region, such as near the edge of the display region, or are regularly or irregularly dispersed, the corresponding effect can be obtained. can get.

  In one aspect of the electro-optical device according to the aspect of the invention, the black image portion displayed for each frame period includes the unit obtained by dividing the image display area into at least one of the vertical direction and the horizontal direction as a unit area. It is displayed in a predetermined pattern area consisting of one or a plurality of areas.

  According to this aspect, for example, one or a plurality of pixel portions which are vertical lines composed of one row of pixel portions, horizontal lines composed of one row of pixel portions, or a cross shape or L-shape including these vertical lines and horizontal lines. The black image portion is displayed for each frame period in the predetermined pattern area. Each time the frame period is switched, the area in which such a black image portion is displayed is sequentially switched or irregularly switched, and the entire area of the image display area is taken over a time corresponding to N frame periods. In addition, a solid black image is displayed in a time-sharing manner. Thereby, a visual afterimage can be reduced.

  In this aspect, the unit area may be configured to be fixed or variable in the vertical and horizontal directions.

  With this configuration, if the unit area is fixed in the vertical and horizontal directions, for example, a vertical line consisting of only one row of pixel portions or a horizontal line consisting of only two rows of pixel portions, the black image portion of the predetermined pattern is a frame. Each time the period is switched, the pattern moves without changing the pattern shape, for example, the black line simply moves in the direction intersecting the extending direction, or the black line is displayed around. Alternatively, if the unit area is made variable, the black image portion changes its pattern shape so that, for example, the black line moves in the direction intersecting the extension direction while changing the thickness each time the frame period is changed. Moving. Furthermore, the vertical and horizontal directions of the unit area are determined according to the type of display image or according to the model of the electro-optical device, and this is fixed when displaying a series of display images or when displaying with the same model. You may make it do. In either case, a solid black image is displayed in a time-division manner over the entire image display area over a time corresponding to N frame periods, and a visual afterimage can be reduced.

  In another aspect of the electro-optical device according to the aspect of the invention, the driving unit may drive the plurality of pixel units based on the image signal through active matrix driving via signal lines connected to the plurality of pixel units. Before being supplied to the driving means and the signal line driving means, a part of the image signal is replaced with a black signal component corresponding to the black image so that the black image is displayed in the time division or Signal processing means for inserting the black signal component into a part of the image signal.

  According to this aspect, the signal processing means replaces a part of the image signal with the black signal component corresponding to the black image so that the black image is displayed in time division. Alternatively, a black signal component is inserted into a part of the image signal. Thereafter, for example, a signal line driving unit such as a scanning line driving circuit or a data line driving circuit performs active matrix driving of the plurality of pixel portions based on the image signal processed in this way. As a result, it is possible to display the display image while reducing the visual afterimage due to the presence of the black image displayed in time division.

  In the aspect including the signal processing unit, the signal processing unit may be configured to include an external circuit that is retrofitted to the substrate of the electro-optical device.

  If comprised in this way, the structure of this aspect can be constructed | assembled comparatively easily, for example by building a signal processing means in an external IC circuit. In particular, the electro-optical device portion including the signal line driving means, excluding the signal processing means, may be configured to perform active matrix driving normally (that is, irrespective of the black image insertion). On the other hand, if an external circuit is attached, the configuration of the present invention can be obtained, which is very advantageous.

  In the aspect provided with this signal processing means, the black signal component may correspond to a voltage within a range from a voltage when displaying black as the display image to a voltage when displaying gray.

  With this configuration, a black image can be displayed by using a part of the power supply and driving function used when displaying a normal display image (that is, unrelated to the black image insertion). The electro-optical device portion including the means only needs to be configured so as to normally perform active matrix driving. Thus, afterimage can be reduced relatively easily.

  In the aspect provided with this signal processing means, the black signal component may be configured to correspond to a voltage outside the range from the voltage when displaying black as the display image to the voltage when displaying gray.

  Even with this configuration, a black image can be displayed with a power supply different from the power supply used when displaying a normal display image or a drive function different from the drive function used when displaying a normal display image. As a result, afterimages can be reduced.

  In another aspect of the electro-optical device according to the aspect of the invention, the driving unit is displayed corresponding to a line-shaped array including a part of the plurality of pixel portions arranged in a line-shaped region extending in a predetermined direction. Active matrix driving is performed so that the black image is displayed by scanning one or a plurality of black lines in a scanning direction intersecting the predetermined direction.

  According to this aspect, one or a plurality of black lines are scanned in the scanning direction on the display image, and a solid black image is formed on the display image as a set of black lines over a time corresponding to N frame periods. Is displayed. At this time, the thickness of the black line may be one pixel portion or plural pixel portions. Further, it may be fixed in the plane of the image display area or may be variable. Moreover, it may be fixed with respect to a series of display images, or may be variable. Furthermore, it may be fixed to the electro-optical device of the same model, or may be variable. In addition, when a plurality of black lines are displayed at the same time, these black lines may be scanned in the same scanning direction or in different scanning directions. In addition, such black line scanning may be performed at a uniform speed over all frames, or may be performed at a variable speed, for example, every two frames or every three frames. In addition, the black line may appear and be scanned intermittently.

  In the aspect relating to the scanning of the black line, the driving unit is active so as to display the black image by scanning the black line in the horizontal direction, the vertical direction, or the diagonal direction in the image display region as the scanning direction. It may be configured to perform matrix driving.

  With this configuration, the black line is scanned in the horizontal direction from the left edge to the right edge, for example, or scanned in the vertical direction from the upper edge to the lower edge over a time corresponding to N frame periods. , Scanned in an oblique direction from the upper left edge to the lower right edge. This completes the scanning of the entire display image. That is, the display image of a solid black image is completed by time division.

  In the aspect relating to the scanning of the black line, the driving unit may be configured to perform active matrix driving so that the black image is displayed by scanning the black line bidirectionally as the scanning direction.

  With this configuration, the black line is scanned horizontally from the left edge to the right edge, for example, and then scanned horizontally from the right edge to the left edge, or vertically scanned from the upper edge to the lower edge. Later, scanning is performed in the vertical direction from the lower edge to the upper edge, or in the oblique direction from the upper left edge to the lower right edge, and then in the oblique direction from the lower right edge to the upper left edge.

  Alternatively, in another aspect of the electro-optical device according to the aspect of the invention, the driving unit may include one or more black lines displayed on the plurality of pixel portions arranged in a line-shaped region extending in a first predetermined direction. One or more black lines displayed in a linear region extending in a second predetermined direction different from the first predetermined direction are scanned in a first scanning direction intersecting the first predetermined direction in the second predetermined direction. The active matrix drive is performed so that the black image is displayed by scanning in the second scanning direction intersecting with the above.

  According to this aspect, for example, the first linear array extending in the vertical direction is scanned in the horizontal direction while the second linear array extending in the horizontal direction is scanned in the vertical direction, so that the appearance is black. The cross pattern or the L-shaped pattern moves diagonally and the entire display image is scanned, so that a solid black image is displayed in a time-sharing manner.

  In this aspect, the driving means may perform active matrix driving so that the scanning speed in the first scanning direction and the scanning speed in the second scanning direction can be set independently of each other. Alternatively, active matrix driving may be performed so that the scanning speed in the first scanning direction is equal to the scanning speed in the second scanning direction.

  In order to solve the above problems, a drive circuit for an electro-optical device of the present invention is a drive circuit for an electro-optical device that drives an electro-optical device including a plurality of pixel portions arranged in a plane in an image display region. A signal line for active matrix driving the plurality of pixel units via signal lines connected to the plurality of pixel units based on the image signal so that a display image corresponding to the signal is displayed in the image display region. Before being supplied to the driving means and the signal line driving means, a solid black image is displayed on the display image in a time-sharing manner over a time corresponding to a multiple of the frame period of the display image. As described above, the image processing apparatus includes signal processing means for replacing a part of the image signal with a black signal component corresponding to the black image or inserting the black signal component into a part of the image signal.

  According to the driving circuit of the electro-optical device of the present invention, the signal processing unit replaces a part of the image signal with the black signal component corresponding to the black image so that the black image is displayed in time division. Alternatively, a black signal component is inserted into a part of the image signal. Thereafter, for example, a signal line driving unit such as a scanning line driving circuit or a data line driving circuit performs active matrix driving of the plurality of pixel portions based on the image signal processed in this way. As a result, it is possible to display a display image while suppressing a decrease in luminance and reducing a visual afterimage in substantially the same manner as in the electro-optical device of the present invention described above.

  In order to solve the above-described problem, an image signal generation device of the present invention has a plurality of pixel units arranged in a plane in an image display area, and a display image corresponding to the image signal is displayed in the image display area. An image signal generation device that supplies the image signal to an electro-optical device including a driving unit that performs active matrix driving of the plurality of pixel units based on a signal, the image signal generation device including a plurality of times a frame period of the display image Or a part of the image signal is replaced with a black signal component corresponding to the black image so that a solid black image is displayed on the display image in a time-division manner over the time corresponding to A signal processing means for inserting the black signal component into a part thereof, and a supplier for supplying the image signal after the replacement or insertion processing by the signal processing means to the electro-optical device Provided with a door.

  According to the image signal generation device of the present invention, the signal processing means replaces a part of the image signal with the black signal component corresponding to the black image so that the black image is displayed in a time division manner. Alternatively, a black signal component is inserted into a part of the image signal. Thereafter, the supply unit supplies the image signal after such processing to the electro-optical device. Therefore, for example, when an electro-optical device including a driving unit such as a scanning line driving circuit or a data line driving circuit performs active matrix driving on a plurality of pixel units based on an image signal after such processing is performed, the above-described operation is performed. As in the case of the electro-optical device of the present invention, it is possible to display a display image while suppressing a decrease in luminance and reducing a visual afterimage.

  In order to solve the above-described problem, a driving method of an electro-optical device according to the present invention is a driving method of an electro-optical device that drives an electro-optical device including a plurality of pixel portions arranged in a plane in an image display region. A signal line for active matrix driving the plurality of pixel units via signal lines connected to the plurality of pixel units based on the image signal so that a display image corresponding to the signal is displayed in the image display region. Before the driving step and the signal line driving step, a solid black image is displayed on the display image in a time-sharing manner over a time corresponding to a multiple of the frame period of the display image. A signal processing step of replacing a part of the image signal with a black signal component corresponding to the black image or inserting the black signal component into a part of the image signal.

  According to the driving method of the electro-optical device of the present invention, the signal processing step replaces a part of the image signal with the black signal component corresponding to the black image so that the black image is displayed in a time division manner. Alternatively, a black signal component is inserted into a part of the image signal. Thereafter, in a signal line driving process such as a scanning line driving circuit or a data line driving circuit, a plurality of pixel portions are driven in an active matrix manner based on the image signal thus processed. As a result, it is possible to display a display image while suppressing a decrease in luminance and reducing a visual afterimage in substantially the same manner as in the electro-optical device of the present invention described above.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention (including various aspects thereof).

  Since the electronic apparatus of the present invention includes the above-described electro-optical device of the present invention, a projection display device and a liquid crystal television capable of displaying a high-quality image with relatively high luminance and reduced afterimage. Various electronic devices such as mobile phones, electronic notebooks, word processors, viewfinder type or monitor direct-view type video tape recorders, workstations, videophones, POS terminals, and touch panels can be realized. Further, as the electronic apparatus of the present invention, for example, an electrophoretic device such as electronic paper can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the electro-optical device of the present invention is applied to a TFT active matrix driving type liquid crystal device.

(Embodiment of electro-optical device)
An embodiment of an electro-optical device according to the present invention including a drive circuit and an image signal generation device according to the present invention will be described with reference to FIGS.

  First, the configuration and operation of the entire electro-optical device will be described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram of the electro-optical device, and FIG. 2 is an equivalent circuit of various elements, wirings, and the like in a plurality of pixel portions formed in a matrix constituting the image display area of the electro-optical panel. is there.

  1, the electro-optical device includes an electro-optical panel 100P, a scanning line driving circuit 104, a data line driving circuit 101, a panel driving circuit 160, and a black insertion control circuit 170, and an image signal Si and synchronization from a video source 180. The signal Ss is input.

  The plurality of pixel portions 10p are arranged in a plane in a matrix in the image display area 10a of the electro-optical panel 100P. An example of the “driving unit” according to the present invention includes the scanning line driving circuit 104, the data line driving circuit 101, the panel driving circuit 160, and the black insertion control circuit 170. More specifically, an example of the “signal line driving unit” according to the present invention includes the scanning line driving circuit 104 and the data line driving circuit 101, and the “signal processing unit” or the “image signal generation” according to the present invention. An example of the “circuit” includes a panel drive circuit 160 and a black insertion control circuit 170.

  As shown in FIG. 2, the electro-optical panel 100P is formed with a pixel electrode 9a and a TFT 30 for switching control of the pixel electrode 9a in each of a plurality of pixel portions. A data line 6 a to which an image signal is supplied is electrically connected to the source of the TFT 30. The image signals S1, S2,..., Sn written to the data lines 6a may be supplied line-sequentially in this order, or may be supplied for each group to a plurality of adjacent data lines 6a. Good.

  Further, the gate electrode is electrically connected to the gate of the TFT 30, and the scanning signals G1, G2,..., Gm are applied to the scanning line 3a and the gate electrode in a pulse sequential manner in this order at a predetermined timing. It is configured as follows. The pixel electrode 9a is electrically connected to the drain of the TFT 30, and the image signal S1, S2,..., Sn supplied from the data line 6a is obtained by closing the switch of the TFT 30 as a switching element for a certain period. Write at a predetermined timing.

  Image signals S 1, S 2,..., Sn written in a liquid crystal as an example of an electro-optical material via the pixel electrode 9 a are held for a certain period with the counter electrode formed on the counter substrate. The liquid crystal modulates light and enables gradation display by changing the orientation and order of the molecular assembly depending on the applied voltage level. In the normally white mode, the transmittance for incident light is reduced according to the voltage applied in units of each pixel, and in the normally black mode, the light is incident according to the voltage applied in units of each pixel. The light transmittance is increased, and light having a contrast corresponding to the image signal is emitted from the electro-optical device as a whole.

  In order to prevent the image signal held here from leaking, a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9a and the counter electrode. The storage capacitor 70 is provided side by side along the scanning line 3a, and includes a capacitor electrode 300 including a fixed potential side capacitor electrode and fixed at a constant potential.

  In FIG. 1 again, the scanning line driving circuit 104 supplies the scanning signals G1, G2,..., Gm to the scanning line 3a at a predetermined timing as described above (see FIG. 2), and the data line driving circuit 101 is as described above. Image signals S1, S2,..., Sn are supplied to the data line 6a at a predetermined timing (see FIG. 2). The data line driving circuit 101 includes, for example, a sampling circuit that samples the image signals S1, S2,..., Sn supplied on the image signal line, and a shift register that supplies a sampling pulse to the sampling circuit. Has been.

  The panel drive circuit 160 uses the scan line drive reference to the scan line drive circuit 104 based on the image signal Si and the synchronization signal Ss input from the video source 180 such as a DVD video player, a video recorder, or a video tuner. The scanning line driving circuit 104 is driven by supplying various signals Sc such as a clock signal (Y clock), an inverted clock signal, a start pulse signal (Y start pulse) serving as a reference for scanning, and a power supply signal. . Further, for the data line driving circuit 101, a clock signal (X clock) or an inverted clock signal that becomes a reference for driving the data line, a start pulse signal (X start pulse) that becomes a reference for starting scanning, for example, parallel-serial development The data line driving circuit 101 is driven by supplying various signals Sd such as image signals S1, S2,..., Sn (see FIG. 2) and a power signal supplied to the data line 6a. Yes.

  Based on the synchronization signal Ss supplied from the video source 180, the black insertion control circuit 170 is a time corresponding to N times the frame period of the display image displayed by the image signal Si (where N is a natural number of 2 or more). Or a part of the image signal Si is replaced with a black signal Sb corresponding to the black image or the image signal Si so that a solid black image is displayed in a time-division manner in an overlapping manner over the entire image display area 10a. The black signal Sb is inserted into a part of the signal.

  Next, the operation of this embodiment will be described with reference to FIGS. 3 and 4 in addition to FIGS. FIG. 3 is a schematic plan view of the image display area 10a that sequentially shows an example of the black image displayed on the display image in four consecutive frames. FIG. 4 is a timing chart showing the contents of the image signals S1, S2,... Sn of each line when such a black image is inserted.

  In FIG. 3, the black insertion control circuit 170 divides the image display area 10a into 4 × 4 = 16 blocks, and vertical black line scanning and horizontal black line scanning are performed using each block as a unit area. In addition, the black signal Sb is inserted into the image signal Si. In the following description, for convenience of explanation, the image display region 10a is described as having 16 pixel portions, that is, one block is composed of one pixel portion. It may be composed of a plurality of pixel parts such as four, eight, nine, twelve, sixteen,... Pixel parts adjacent to each other. That is, the number of pixel portions corresponding to the thickness of the black line can be set to a desired number.

  During the operation, first, as shown in FIG. 3A, in the time zone of 1 + 4m (where m is a natural number) frame, the vertical black line LY is located at the left end of the image display area 10a and is 1 + 4n (note that In the time zone of n), the horizontal black line LX is located at the upper end of the image display area 10a. Subsequently, as shown in FIG. 3B, in the time zone of 2 + 4m frame, the vertical black line LY moves to the second column from the left end of the image display area 10a, and in the period of 2 + 4n frame, the horizontal black line LY moves. LX moves to the second line from the upper end of the image display area 10a. Subsequently, as shown in FIG. 3C, the vertical black line LY moves to the third column from the left end of the image display area 10a in the period of 3 + 4m frame, and in the time zone of 3 + 4n frame, the horizontal black line LY moves. LX moves to the third line from the upper end of the image display area 10a. Subsequently, as shown in FIG. 4D, the vertical black line LY moves to the right end of the image display area 10a within the period of 4 + 4m frame, and the horizontal black line LX is displayed in the time zone of 4 + 4n frame. Move to the lower end of the display area 10a.

  As shown in FIG. 4, in order to display such vertical black lines LY and horizontal black lines LX, the black signal Sb is inserted by the black insertion control circuit 170, so that the following image signal is obtained. It is supplied from the panel drive circuit 160 to the data line drive circuit 101. In the present embodiment, various signals supplied to the scanning line driving circuit 104 are not particularly changed for scanning a black line.

  First, within a period of “1 frame (that is, when n = 1 in a 1 + 4n frame)” defined by the frame signal, to the “line 1” that is the leftmost pixel column (see FIG. 3) extending in the vertical direction. The image signal S1 is a black level signal (a flat level signal shown for “line 1” in FIG. 4) for the pixel portions corresponding to the first to fourth rows, that is, all rows counted from the top. Has been replaced. This is a vertical control signal indicating the horizontal scanning position in each frame of the vertical black line LY and a horizontal control signal indicating the vertical scanning position in each frame of the horizontal black line LX as the black signal Sb from the black insertion control circuit 170. Based on this, in the panel drive circuit 160, a part of the image signal Si is a black level signal. In addition, the image signal S2 goes to “line 2”, which is the second pixel column (see FIG. 3) from the left end extending in the vertical direction, and “line 3” is the third pixel column (see FIG. 3) from the left end extending in the vertical direction. "Image signal S3", the image signal S4 to the "line 4" which is the fourth or rightmost pixel column extending from the left end in the vertical direction (see FIG. 3) is black level for the pixel portion corresponding to the first row from the top. The other pixel portions have image signal levels that constitute a display image corresponding to the image signal Si. Also in this case, a part of the image signal Si is a black level signal based on the vertical control signal and the horizontal control signal from the black insertion control circuit 170. As a result, the vertical black line LY and the horizontal black line LX are displayed as shown in FIG.

  Subsequently, within the period of “2 frames (that is, when n = 1 in the 2 + 4n frame)” defined by the frame signal, the image signal S1 to “line 1”, “line 3”, and “line 4”. , S3 and S4 are black level signals for the pixel portion corresponding to the second row from the top, and the other pixel portions are image signal levels constituting a display image corresponding to the image signal Si. Further, the image signal S2 to “line 2” is a black level signal for the pixel portions corresponding to all rows. As a result, the vertical black line LY and the horizontal black line LX are displayed as shown in FIG.

  Subsequently, within a period of “3 frames (that is, when n = 1 in a 3 + 4n frame)” defined by the frame signal, the image signal S1 to “line 1”, “line 2”, and “line 4” , S2 and S4 are black level signals for the pixel portion corresponding to the third row from the top, and the other pixel portions are image signal levels constituting a display image corresponding to the image signal Si. The image signal S3 to “line 3” is a black level signal for the pixel portions corresponding to all rows. As a result, the vertical black line LY and the horizontal black line LX are displayed as shown in FIG.

  Subsequently, the image signal S1 to “line 1”, “line 2”, and “line 3” is within a period of “4 frames (that is, n = 1 in a 4 + 4n frame)” defined by the frame signal. , S2 and S3 are black level signals for the pixel portion corresponding to the fourth row from the top, and the other pixel portions are image signal levels constituting a display image corresponding to the image signal Si. Further, the image signal S4 to “line 4” is a black level signal for the pixel portions corresponding to all rows. As a result, the vertical black line LY and the horizontal black line LX are displayed as shown in FIG.

  Subsequently, within the period of “5 frames (that is, n = 1 in 1 + 4n frame)” defined by the frame signal, the same operation as that of “1 frame” is performed again, as shown in FIG. Thus, the vertical black line LY and the horizontal black line LX are displayed.

  As a result of the above, according to the present embodiment, the vertical black line LY and the horizontal black line LX scan the entire area of the image display area 10a over a time corresponding to four times the frame period of the display image. A solid black image is displayed in a time-division manner. In other words, the black cross pattern or L-shaped pattern is moved obliquely, so that the entire area of the image display area 10a is scanned, whereby a solid black image is displayed in a time-division manner. Then, for example, a black image portion displayed as a vertical black line LY and a horizontal black line LX in a short time, such as 1/60 seconds as a frame period, is not recognized by human vision in any frame period. However, of the time corresponding to N frame periods, a black image is displayed on each pixel portion over one frame period in any frame period. Therefore, with respect to each pixel portion, afterimages can be significantly reduced due to the presence of a black image that is favorably displayed in black after the liquid crystal is stabilized. Further, afterimages can be reduced in this way for all the pixel portions over a time corresponding to four times the frame period, the afterimages are extremely effective for the entire display image or the entire image display area 10a. Will be reduced. In addition, since the luminance is reduced at a rate of 1/4 for each pixel portion, if N is set according to the required luminance, the luminance reduction is hardly visually noticeable. Can be.

  The black insertion control circuit 170 and the panel drive circuit 160 are external IC circuits that are retrofitted to the substrate 10 on which the electro-optical panel 100P is built together with the scanning line drive circuit 104 and the data line drive circuit 101. You may comprise as follows. With this configuration, the scanning line driving circuit 104, the data line driving circuit 101, and the electro-optical panel 100P need only use ordinary models that are unrelated to black image insertion. By attaching an external IC circuit having a line insertion function, the original effect of reducing the afterimage while reducing the decrease in luminance in this embodiment can be obtained relatively easily, which is very advantageous in practice. In addition, in the above-described embodiment, the number of pixel portions constituting the vertical black line LY and the horizontal black line LX (see FIGS. 3A to 3D) may be different in the vertical and horizontal directions, Further, it may be variable in both vertical and horizontal directions. For example, each time the frame period is switched, at least one of the vertical black line LY and the horizontal black line LX moves while changing its pattern shape, such as moving in the direction intersecting the extending direction while changing the thickness. As described above, the black signal Sb may be inserted by the black insertion control circuit 170. In addition, the scanning speed of the vertical black line LY may be different from the scanning speed of the horizontal black line LX.

  Further, in this embodiment, in order to display a black line, a process of replacing the image signal Si with a black level signal is performed (see FIG. 4). You may comprise so that a line may be displayed.

  It should be noted that the use of the black level signal at the gradation level of the image signal Si as in the present embodiment is advantageous because it does not require a special power supply or driving function. It may be replaced with a black level signal. In either case, the afterimage can be reduced.

(Deformation of electro-optical device)
Next, modified embodiments of the above-described electro-optical device will be described with reference to FIGS. Here, FIGS. 5 to 10 are schematic plan views of the image display area 10a sequentially showing an example of the black image displayed on the display image in a plurality of continuous frames. Note that the modification described below is a modification of the black signal Sb insertion method by the black insertion control device, and other configurations and operations are the same as those in the above-described embodiment.

  In the modification shown in FIG. 5, the image display area divided into 16 blocks is vertically scanned from the upper end to the lower end over a time period of 4 horizontal black lines. As a result, the black image is displayed in a time-division manner over the entire display image over a period of 4 frames. In this case, the decrease in luminance is 3/4 compared to the case where no black line is inserted.

  In the modification of FIG. 6, the image display area divided into 16 blocks is horizontally scanned from the left end to the right end over a time period of 4 black vertical lines. As a result, the black image is displayed in a time-division manner over the entire display image over a period of 4 frames. In this case, the decrease in luminance is 3/4 compared to the case where no black line is inserted.

  In the modification of FIG. 7, the image display area divided into 16 blocks is scanned diagonally from the upper left corner to the lower right corner, with diagonal black lines taking 7 frames. Thus, a black image is displayed in a time-division manner over the entire display image over a period of 7 frames. In this case, the decrease in luminance is 6/7 compared to the case where no black line is inserted.

  In the modification shown in FIG. 8, a plurality of diagonal black lines are moved diagonally from the upper left corner to the lower right corner in two frames over an image display area divided into 16 blocks. As a result, a black image is displayed in a time-division manner over the entire display image over a period of two frames. Alternatively, it can be said that the black image forming the complementary pattern is alternately switched in the frame period, and the black image is displayed in a time-division manner over the entire display image over a period of two frames. In any case, in this case, the decrease in luminance is ½ compared to the case where no black line is inserted.

  The modification of FIG. 9 is a form in which black images are further intermittently inserted in the modification of FIG. That is, a plurality of diagonal black lines move intermittently from the upper left corner to the lower right corner so as to cover the entire display image over a period of four frames. As a result, the black image is displayed in a time-division manner over the entire display image over a period of 4 frames. In this case, the decrease in luminance is 3/4 compared to the case where no black line is inserted.

  As described above, according to the various modifications shown in FIGS. 5 to 9, the black line is scanned over a time corresponding to N frame periods, thereby completing the scanning of the entire display image. At this time, in particular, one black line may be scanned in a predetermined direction as in the modified embodiments of FIGS. 5 to 7, or a plurality of black lines may be scanned in a predetermined direction as in the modified embodiment of FIG. Scanning may be performed, and such scanning or black image display may be performed intermittently as in the modification of FIG.

  In the modification of FIG. 10, the image display area is divided into 2 × 2 = 4 blocks, and each block is a unit area when a black image is displayed in a time-division manner. In this modification, the upper and lower horizontal black lines may be alternately displayed for each frame as shown in FIG. 10A, or the oblique black lines may be alternately displayed for each frame as shown in FIG. Also good. That is, in these cases, N = 2, and a black image is displayed in a time-division manner over the entire image display area over a period of two frames. Alternatively, as shown in FIG. 10 (c), a black image may be displayed in a time-division manner in the entire image display area with N = 3. Further, as shown in FIG. 10 (d), an image display area with N = 4. A black image may be displayed in a time-sharing manner over the entire area.

  If the value of N as described above is at least “2” or more, a corresponding effect can be obtained. On the other hand, if N is made too large, the effect of reducing the afterimage is reduced. Therefore, the actual value of N depends on the characteristics and specifications of the electro-optical device, particularly the required luminance and image quality. It may be determined individually, specifically, experimentally, experimentally, empirically, or by calculation or simulation.

[Overall configuration of electro-optical device]
Hereinafter, the overall configuration of the electro-optical device according to the embodiment will be described with reference to FIGS. 11 and 12. 11 is a plan view of the electro-optical device when the TFT array substrate is viewed from the side of the counter substrate together with each component formed thereon, and FIG. 12 is a cross-sectional view taken along line HH ′ of FIG. It is. Here, a TFT active matrix driving type liquid crystal device with a built-in driving circuit, which is an example of an electro-optical device, is taken as an example.

  11 and 12, in the electro-optical device according to this embodiment, the TFT array substrate 10 and the counter substrate 20 are disposed to face each other. 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 provided with a sealing material 52 provided in a seal region positioned around the image display region 10a. Are bonded to each other.

  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. Further, 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. That is, the electro-optical device according to the present embodiment is suitable for a small and enlarged display for a projector light valve.

  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 region farther than the frame light-shielding film 53, the data line driving circuit 101 and the external circuit connection terminal 102 are provided on one side of the TFT array substrate 10 particularly in the region located outside the sealing region where the sealing material 52 is disposed. It is provided along. The scanning line driving circuit 104 is provided along two sides adjacent to the one side so as to be covered with the frame light shielding film 53. Further, in order to connect the two scanning line driving circuits 104 provided on both sides of the image display area 10a in this way, the TFT array substrate 10 is covered with the frame light shielding film 53 along the remaining side. A plurality of wirings 105 are provided.

  In addition, vertical conduction members 106 that function as vertical conduction 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 corners. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

  In FIG. 12, 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. Further, 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.

  In addition to the data line driving circuit 101, the scanning line driving circuit 104 and the like, the image signal on the image signal line is sampled and supplied to the data line on the TFT array substrate 10 shown in FIGS. Sampling circuit, precharge circuit for supplying a precharge signal of a predetermined voltage level to a plurality of data lines in advance of an image signal, for inspecting the quality, defects, etc. of the electro-optical device during production or at the time of shipment An inspection circuit or the like may be formed.

(Electronics)
Next, an overall configuration, particularly an optical configuration, of an embodiment of a projection color display device as an example of an electronic apparatus using the electro-optical device described in detail as a light valve will be described. FIG. 13 is a schematic cross-sectional view of the projection type color display device.

  In FIG. 13, a liquid crystal projector 1100, which is an example of a projection type color display device according to the present embodiment, prepares three liquid crystal modules including a liquid crystal device having a drive circuit mounted on a TFT array substrate, each of which is a light valve for RGB. It is configured as a projector used as 100R, 100G, and 100B. The above-described electro-optical devices are used for these light valves 100R, 100G, and 100B. In the liquid crystal projector 1100, when projection light is emitted from a lamp unit 1102 of a white light source such as a metal halide lamp, the light components R, G, and R corresponding to the three primary colors of RGB are obtained by three mirrors 1106 and two dichroic mirrors 1108. The light is divided into B and led to the light valves 100R, 100G and 100B corresponding to the respective colors. In particular, the B light is guided through a relay lens system 1121 including an incident lens 1122, a relay lens 1123, and an exit lens 1124 in order to prevent light loss due to a long optical path. The light components corresponding to the three primary colors modulated by the light valves 100R, 100G, and 100B are synthesized again by the dichroic prism 1112 and then projected as a color image on the screen 1120 via the projection lens 1114.

  Next, an example in which the above-described electro-optical device is applied to a mobile personal computer will be described. FIG. 14 is a perspective view showing the configuration of this personal computer.

  In FIG. 14, the computer 1200 includes a main body 1204 provided with a keyboard 1202 and a liquid crystal display unit 1206. The liquid crystal display unit 1206 is configured by adding a backlight to the back surface of the liquid crystal panel 1005 described above.

  Further, an example in which the above-described electro-optical device is applied to a mobile phone will be described. FIG. 15 is a perspective view showing the configuration of this mobile phone.

  In FIG. 15, a cellular phone 1040 includes a reflective liquid crystal panel 1005 together with a plurality of operation buttons 1302. In the reflective liquid crystal panel 1005, a front light is provided on the front surface thereof as necessary.

  In addition to the electronic devices described with reference to FIGS. 13 to 15, a liquid crystal television, a viewfinder type, a monitor direct view type video tape recorder, a car navigation device, a pager, an electronic notebook, a calculator, a word processor, a work Examples include a station, a videophone, a POS terminal, a device equipped with a touch panel, and the like. Needless to say, the present invention can be applied to these various electronic devices.

  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, The drive circuit, the image signal generation device, and the electronic device are also included in the technical scope of the present invention.

1 is a block diagram illustrating an overall configuration of a liquid crystal device according to an embodiment of the present invention. 4 is an equivalent circuit of various elements, wirings, and the like in a plurality of pixel portions formed in a matrix that forms an image display area of an electro-optical panel in the embodiment. In an embodiment, it is a schematic plan view of an image display area which shows an example of a black image displayed on a display image in a series of four frames in order. 5 is a timing chart showing the contents of image signals S1, S2,..., Sn of each line when a black image is inserted in the embodiment. In one modification, it is a schematic plan view of an image display area that sequentially shows a black image that is displayed superimposed on a display image in a plurality of consecutive frames. In another modification, it is a schematic plan view of an image display region that sequentially shows a black image that is displayed superimposed on a display image in a plurality of consecutive frames. In another modification, it is a schematic plan view of an image display region that sequentially shows a black image that is displayed superimposed on a display image in a plurality of consecutive frames. In another modification, it is a schematic plan view of an image display region that sequentially shows a black image that is displayed superimposed on a display image in a plurality of consecutive frames. In another modification, it is a schematic plan view of an image display region that sequentially shows a black image that is displayed superimposed on a display image in a plurality of consecutive frames. In another modification, it is a schematic plan view of an image display region that sequentially shows a black image that is displayed superimposed on a display image in a plurality of consecutive frames. It is a top view which shows the whole structure of a liquid crystal device. It is H-H 'sectional drawing of FIG. It is sectional drawing which shows the structure of the projector which is an example of the electronic device to which a liquid crystal device is applied. It is sectional drawing which shows the structure of the personal computer which is an example of the electronic device to which a liquid crystal device is applied. It is sectional drawing which shows the structure of the mobile telephone which is an example of the electronic device to which a liquid crystal device is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10a ... Image display area, 10p ... Pixel part, 100P ... Electro-optical panel, 101 ... Data line drive circuit, 104 ... Scan line drive circuit, 160 ... Panel drive circuit, 170 ... Black insertion control circuit, 180 ... Video source

Claims (15)

A plurality of pixel portions arranged in a plane in the image display area;
A solid black image is superimposed on the display image in a time-division manner so that a display image corresponding to the image signal is displayed in the image display area and takes a time corresponding to a multiple of the frame period of the display image. An electro-optical device comprising: a driving unit that performs active matrix driving on the plurality of pixel portions so as to be displayed. The black image portion displayed for each frame period is a predetermined pattern area composed of one or a plurality of unit areas, with a unit area defined by dividing the image display area into at least one of the vertical direction and the horizontal direction. The electro-optical device according to claim 1, wherein the electro-optical device is displayed. The electro-optical device according to claim 2, wherein the unit area can be set to be fixed or variable in the vertical and horizontal directions. The driving means includes
Signal line driving means for active matrix driving the plurality of pixel portions based on the image signals via signal lines connected to the plurality of pixel portions;
Before being supplied to the signal line driving means, a part of the image signal is replaced with a black signal component corresponding to the black image so that the black image is displayed in the time division or one of the image signals. The electro-optical device according to claim 1, further comprising: a signal processing unit that inserts the black signal component into a part. The electro-optical device according to claim 4, wherein the signal processing unit includes an external circuit that is retrofitted to a substrate of the electro-optical device. 6. The electro-optical device according to claim 4, wherein the black signal component corresponds to a voltage within a range from a voltage when displaying black as the display image to a voltage when displaying gray. 6. The electro-optical device according to claim 4, wherein the black signal component corresponds to a voltage outside a range from a voltage when displaying black as the display image to a voltage when displaying gray. The driving means intersects one or more black lines displayed in a predetermined direction corresponding to a line-shaped array formed of a part of the plurality of pixel portions arranged in a line-shaped region extending in a predetermined direction. 8. The electro-optical device according to claim 1, wherein active matrix driving is performed so that the black image is displayed by scanning in a scanning direction. The driving means performs active matrix driving so as to display the black image by scanning the black line in the horizontal direction, vertical direction, or diagonal direction in the image display area as the scanning direction. 9. The electro-optical device according to 8. The electro-optical device according to claim 8, wherein the driving unit performs active matrix driving so that the black image is displayed by scanning the black line in both directions as the scanning direction. The driving unit scans one or a plurality of black lines displayed in the plurality of pixel portions arranged in a line-shaped region extending in a first predetermined direction in a first scanning direction intersecting the first predetermined direction. At the same time, by scanning one or more black lines displayed in a line-shaped region extending in a second predetermined direction different from the first predetermined direction in the second scanning direction intersecting the second predetermined direction, the black 8. The electro-optical device according to claim 1, wherein active matrix driving is performed so that an image is displayed. A drive circuit for an electro-optical device that drives an electro-optical device including a plurality of pixel units arranged in a plane in an image display area,
A signal for active matrix driving the plurality of pixel portions via signal lines connected to the plurality of pixel portions based on the image signal so that a display image corresponding to the image signal is displayed in the image display region. Line driving means;
Before being supplied to the signal line driving means, the solid black image is displayed on the display image in a time-division manner over a time corresponding to a plurality of times the frame period of the display image. A signal processing means for replacing a part of the image signal with a black signal component corresponding to the black image or inserting the black signal component into a part of the image signal; circuit. A plurality of pixel units arranged in a plane in the image display area, and driving means for active matrix driving the plurality of pixel parts based on the image signal so that a display image corresponding to the image signal is displayed in the image display area An image signal generation device that supplies the image signal to an electro-optical device including:
A portion of the image signal is displayed in black corresponding to the black image so that a solid black image is displayed on the display image in a time-division manner over a time corresponding to a multiple of the frame period of the display image. A signal processing means for replacing with a signal component or inserting the black signal component into a part of the image signal;
An image signal generation apparatus comprising: a supply unit that supplies the image signal after the replacement or insertion process is performed by the signal processing unit to the electro-optical device. An electro-optical device driving method for driving an electro-optical device including a plurality of pixel units arranged in a plane in an image display region,
A signal for active matrix driving the plurality of pixel portions via signal lines connected to the plurality of pixel portions based on the image signal so that a display image corresponding to the image signal is displayed in the image display region. A line driving process;
Before the signal line driving step, the image signal of the image signal is displayed such that a solid black image is displayed in a time-division manner on the display image over a time corresponding to a multiple of a frame period of the display image. A signal processing step of partially replacing the black signal component corresponding to the black image or inserting the black signal component into a part of the image signal. An electronic apparatus comprising the electro-optical device according to claim 1.

Images