JP2009223259A - Liquid crystal driving device, and liquid crystal device and method of driving the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal driving device and the like that improve a swing-back phenomenon at a low cost. <P>SOLUTION: An image processing controller 200 includes an N-fold speed driving unit 210 which divides one frame into N (N: a natural number of not less than 2) fields, and a driving compensation unit 220 which performs driving compensation on the liquid crystal layer of the liquid crystal device. The driving compensation unit 220 performs overdrive driving in an M-th (M: a natural number smaller than N) field among the N fields such that display gradation overshoots a target gradation, and performs overdrive driving in the polarity direction opposite to the overdrive driving in the M-th field in an (M+1)-th field among the N fields. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal driving device, a liquid crystal device, and a driving method thereof.

  In recent years, liquid crystal devices have been widely used as low power consumption and space saving display devices. Such a liquid crystal device is rapidly spreading not only as a monitor device of a computer but also as a display device for portable equipment typified by a cellular phone and a display device for a television receiver. On the other hand, the performance of liquid crystal devices has been remarkably improved, and liquid crystal devices that can replace CRT display devices of desktop computers and workstations have appeared due to improved response speed and contrast ratio.

  In recent years, large screen display devices and small display devices are increasingly used for displaying moving images, and liquid crystal devices are required to respond to moving images at high speed. However, it is well known that the liquid crystal device is inferior in response speed as compared with a CRT (cathode ray tube). Therefore, it is strongly desired to improve response speed and realize good moving image display performance in the liquid crystal device.

  The cause of the slow response speed of the liquid crystal device includes the liquid crystal mode used, the liquid crystal material, the pixel structure, and the like. In addition, the response speed of the liquid crystal device also decreases depending on the usage situation. For example, the response speed of the liquid crystal device becomes even slower when used in a low temperature atmosphere or when the gradation changes from an intermediate gradation to an intermediate gradation. If the response speed of the liquid crystal device becomes slower than one frame period (about 16 ms when the frame rate is a general 60 fps) due to the above causes and usage conditions, the displayed moving image is blurred, Afterimages, tailing, etc. will occur.

  As drive control for increasing the response speed of such a liquid crystal device, so-called overdrive drive compensation is known. Overdrive driving compensation is a technique for applying a gradation voltage higher than a target gradation within one frame period.

  As a related technique, the following Patent Document 1 discloses a liquid crystal panel having a plurality of signal lines and a plurality of scanning lines, a signal driver circuit that applies a display voltage corresponding to liquid crystal display data to the signal lines, and A scanning driver circuit for supplying a scanning instruction signal to the scanning line, and a liquid crystal for driving the signal driver circuit and the scanning driver circuit with a display control signal (input control signal) and display data (input display data) supplied from the outside In a liquid crystal display device comprising a control signal and a liquid crystal control circuit for converting liquid crystal display data, the liquid crystal control circuit includes display data conversion means for converting input display data by a predetermined conversion method and outputting corrected liquid crystal display data. 1 frame period, which is the time of one cycle of the input control signal, is divided into N (N is an integer of 2 or more, and 1 divided period is a field), and scanning lines The scan driver circuit is divided into N groups including a plurality of scan lines adjacent to each other, and the scan driver circuit includes two scan lines of two groups out of the N groups in each field period. The N fields included in one frame period of each group, which are alternately selected for each scanning line fewer than the number, include a field driven by the corrected liquid crystal display data converted by the display data conversion means, and display data conversion And a field driven by liquid crystal display data which is not converted by the means.

  However, even with overdrive drive compensation, depending on the liquid crystal mode, the response speed can be improved only by about one frame period (about 16 ms) in the case of a gradation change from an intermediate gradation to an intermediate gradation. I can't.

  By the way, a vertical alignment mode liquid crystal device, particularly a multi-mode vertical alignment (hereinafter referred to as MVA) type liquid crystal device in which a plurality of domains having different tilt directions of liquid crystal molecules in a pixel region are formed, has a contrast ratio. And can contribute to the provision of a display device that provides a wide viewing angle.

  However, with regard to the response speed of the MVA type liquid crystal device, if it is driven in the order of black, white and black, the image quality can be improved by the high-speed response of the liquid crystal. Even if drive drive compensation is performed, there is a problem that a so-called back-fluctuation phenomenon occurs and the quality of a moving image cannot be improved.

  A technique for improving the slip-back phenomenon is disclosed in Patent Document 2, for example. Patent Document 2 discloses a liquid crystal device in which a pretilt is formed by a polymer layer that tilts liquid crystal molecules in a predetermined tilt direction.

Japanese Patent No. 3749433 JP 2005-338199 A

  The present invention has been made in view of the above technical problems, and an object of the present invention is to provide a liquid crystal driving device, a liquid crystal device, and a driving method thereof that can improve the rebound phenomenon at low cost. There is.

In order to solve the above problems, the present invention
A liquid crystal driving device for driving a liquid crystal device,
Double speed driving means for dividing one frame into N (N is a natural number of 2 or more) fields;
Drive compensation means for performing drive compensation when driving the liquid crystal layer of the liquid crystal device;
Including
The drive compensation means;
In the Mth field (M is a natural number smaller than N) among the N fields, the display grayscale is overdriven so that the display grayscale overshoots the target grayscale, and the Nth field among the N fields is driven. In the field of (M + 1), the present invention relates to a liquid crystal driving device characterized in that overdrive driving is performed in the opposite polarity direction to the overdrive driving in the Mth field.

  According to the present invention, in the Mth field, overdrive driving is performed so that the display gradation overshoots the target gradation. As a result, it is possible to improve the rebound phenomenon, enhance the edges of the image, and make the moving image look sharper. In the (M + 1) th field, overdrive is performed in the polarity direction opposite to the overdrive in the Mth field. As a result, blurring and tailing of the image can be reduced. In addition, it can be realized at a very low cost by utilizing the structure of an existing liquid crystal device.

In the liquid crystal driving device according to the present invention,
When driving compensation is performed on a j-th frame (j is a natural number of 2 or more),
The second means comprises:
The image data of the Mth and (M + 1) th frames is corrected for each dot based on the difference between the image data of the jth and (j−1) th frames, and an overdrive voltage corresponding to the image data is obtained. The liquid crystal layer can be applied.

In the liquid crystal driving device according to the present invention,
The second means comprises:
The overdrive voltage can be applied to the liquid crystal layer such that the greater the difference between the image data of the jth and (j−1) th frames, the greater the overdrive voltage in the Mth field.

In the liquid crystal driving device according to the present invention,
The liquid crystal device is
A liquid crystal layer which forms a plurality of domains and operates in a vertical alignment mode can be provided.

The present invention also provides
A liquid crystal device having a liquid crystal layer that forms a plurality of domains and operates in a vertical alignment mode,
A first electrode to which a driving voltage corresponding to gradation data is applied;
A second electrode to which a given common voltage is applied;
The liquid crystal layer sandwiched between the first and second electrodes;
The liquid crystal driving device according to claim 4, wherein the liquid crystal driving device drives the first electrode.
It relates to the liquid crystal device characterized by including.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid crystal device which can implement | achieve the improvement of the rebound phenomenon at low cost can be provided.

In the liquid crystal device according to the present invention,
A backlight for supplying light to the liquid crystal layer;
A backlight control device for controlling the backlight;
Further including
The backlight control device is
The backlight can be controlled to be turned off in the Mth field, and the backlight can be turned on in the (M + 1) field.

The present invention also provides
A method of driving a liquid crystal device,
Dividing one frame into N (N is a natural number of 2 or more) fields;
Performing drive compensation when driving the liquid crystal layer of the liquid crystal device;
Including
Performing the drive compensation comprises:
In the Mth field (M is a natural number smaller than N) among the N fields, the display grayscale is overdriven so that the display grayscale overshoots the target grayscale, and the Nth field among the N fields is driven. In the (M + 1) field, the present invention relates to a driving method of a liquid crystal device, characterized in that overdrive driving is performed in a direction opposite to the overdrive driving in the Mth field.

In the driving method of the liquid crystal device according to the present invention,
When driving compensation is performed on a j-th frame (j is a natural number of 2 or more),
The image data of the Mth and (M + 1) th frames is corrected for each dot based on the difference between the image data of the jth and (j−1) th frames, and an overdrive voltage corresponding to the image data is obtained. The liquid crystal layer can be applied.

In the driving method of the liquid crystal device according to the present invention,
The overdrive voltage can be applied to the liquid crystal layer such that the greater the difference between the image data of the jth and (j−1) th frames, the greater the overdrive voltage in the Mth field.

In the driving method of the liquid crystal device according to the present invention,
The liquid crystal device is
A liquid crystal layer which forms a plurality of domains and operates in a vertical alignment mode can be provided.

  According to any one of the above-described inventions, it is possible to provide a method for driving a liquid crystal device that can improve the rebound phenomenon at low cost.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. Also, not all of the configurations described below are essential constituent requirements of the present invention. The same constituent elements are denoted by the same reference numerals and description thereof is omitted.

1. Liquid Crystal Device FIG. 1 shows a configuration example of an electronic apparatus to which a liquid crystal device according to this embodiment is applied. FIG. 1 shows an example in which a display module is employed as the liquid crystal device. FIG. 1 shows an example of a personal computer system connected to a liquid crystal display device as an electronic device. For example, a mobile phone, a portable information device (PDA, etc.), a digital camera, a projector, a portable audio player, a mass storage It may be a device, a video camera, an electronic notebook, a GPS (Global Positioning System) device, a game device, a projector (projection display device), or the like.

  The personal computer system 10 includes a display module 100, a host 700, and a set-side image processing device 710. The host 700 is a personal computer main body or the like, and has a central processing unit (CPU) and a storage medium such as a memory and a hard disk device, and generates image data of an image to be displayed on the display module 100. The set-side image processing device 710 performs image processing such as scaler processing on the image data from the host 700. In the display module 100, image processing is further performed on the image data from the set-side image processing device 710, and image display control based on the image data after the image processing is performed.

  The display module 100 (liquid crystal device in a broad sense) includes a display panel 110 (electro-optical device in a broad sense). In the display panel 110, a display panel 110 that is an LCD panel is formed on a panel substrate. The display panel 110 is an active matrix panel, and includes a plurality of gate lines, a plurality of source lines, and a plurality of pixels in which each pixel is specified by each gate line and each source line.

  FIG. 2 shows an example of an equivalent circuit of a pixel of the display panel 110 in FIG.

Each gate line of the plurality of gate lines of the display panel 110 is arranged so as to intersect with each source line of the plurality of source lines, and each pixel is provided in a region corresponding to the intersection position of each gate line and each source line. . In Figure 2, pixels are provided in a region corresponding to the intersections of the gate lines G _u and the source line S _v.

Pixels provided in regions corresponding to intersections of the gate lines _{G u} and the source line _{S v} is a thin film transistor (Thin Film Transistor: TFT) having a _{STR vu.} TFT _{STR vu} source to the source line _{S v} of the connection, the gate line _{G u} to the gate of the thin film transistor _{STR vu} is connected, the drain to a pixel electrode _{PE vu} of the thin film transistor _{STR vu} is connected. When the thin film transistor _{STR vu} which is connected to the selected gate line _{G u} is turned on, applied to the pixel electrode _{PE vu} the voltage of the source line _{S v} which is connected to the source of the thin film transistors _{STR vu} is connected to the drain of the thin film transistor _{STR vu} Is done. A common electrode VCOM to which a given common voltage is applied is provided facing the pixel electrode PE _vu . Liquid crystal (electro-optic element in a broad sense) is sealed as a liquid crystal layer between the pixel electrode PE _vu and the common electrode VCOM, and the transmittance of the pixel changes according to the voltage applied to the liquid crystal.

Further, in order to prevent a change in the transmittance of the pixel due to a liquid crystal leak or the like, an auxiliary capacitor (holding capacitor, storage capacitor) CS is provided in parallel with the pixel electrode PE _vu in order to hold a charge corresponding to the applied voltage of the liquid crystal. _vu is provided. In FIG. 2, one end of the auxiliary capacitor CS _vu is connected to the pixel electrode PE _vu, and the other end of the auxiliary capacitor CS _vu is connected to the common electrode VCOM. However, another voltage is applied to the other end of the auxiliary capacitor CS _vu. You may be comprised so that. By providing the auxiliary capacitor CS _vu , once the voltage of the pixel electrode PE _vu is applied, the voltage can be steadily applied to the liquid crystal (liquid crystal layer).

  By the way, the display panel in the present embodiment is a liquid crystal display (LCD) panel that operates in a vertical alignment mode. More specifically, the display panel 110 is an MVA type LCD panel in which a plurality of domains having different tilt directions of liquid crystal molecules in a pixel region are formed.

  FIG. 3 schematically shows a cross-sectional structure of the display panel 110 in the present embodiment.

The display panel 110 includes a TFT substrate (panel substrate) 112 on which pixel electrodes are formed and a common substrate 114 on which common electrodes are formed, and a liquid crystal layer in which liquid crystal is sealed between the TFT substrate 112 and the common substrate 114. Have Pixel electrodes 116 _{1 to} 116 ₃ having a shape called a rib are formed on the TFT substrate 112. On the common substrate 114, common electrodes 118 ₁ and 118 ₂ having a shape called a rib are formed. Then, with the ribs of both substrates facing each other, both substrates are bonded together so that liquid crystal is sealed between them. As a result, the liquid crystal molecules LC1 to LC5 are aligned to form a plurality of domains.

  FIG. 4 shows an outline of the configuration of the display panel 110.

Further, as shown in FIG. 4, the display panel 110 includes first and second polarizing filters (polarizing elements) 119 ₁ having polarization directions orthogonal to each other on both sides of the TFT substrate 112 and the common substrate 114. It has a 119 _2. For example, the first polarizing filter 119 ₁ is disposed outside the common substrate 114 and has a light absorption axis in a given direction parallel to the main surface of the common substrate 114. The second polarizing filter 119 ₂ is disposed outside the TFT substrate 112, and has a light absorption axis in a direction orthogonal to the light absorption axis of the first polarizing filter 119 ₁ , parallel to the main surface of the TFT substrate 112. .

  In order to drive such a display panel 110, the display module 100 is provided with a liquid crystal driving device 150 as shown in FIG. The liquid crystal driving device 150 includes a gate substrate 120, a data substrate 130, and a control substrate 140.

The gate substrate 120 is a flexible substrate on which one or a plurality of gate drivers 122 _{1 to} 122 _K (K is a natural number) for scanning a plurality of gate lines of the display panel 110 are mounted. The gate substrate 120 differs from the display panel 110 (display module 100) so that the output electrodes of the gate drivers 122 _{1 to} 122 _K provided on the gate substrate 120 are electrically connected to the plurality of gate lines of the display panel 110. Anisotropic conductive film (ACF) is connected.

The data substrate 130 is a flexible substrate on which one or a plurality of source drivers 132 _{1 to} 132 _J (J is a natural number) for driving a plurality of source lines of the display panel 110 based on image data. The data board 130 is connected to the display panel 110 (display module 100) so that the output electrodes of the source drivers 132 _{1 to} 132 _J provided on the data board 130 are electrically connected to the plurality of source lines of the display panel 110. Connected.

  The control board 140 is a printed circuit board on which an interface (I / F) circuit 142, a memory 144, and an image processing controller (an image processing apparatus in a broad sense) 200 are mounted. The I / F circuit 142 performs I / F processing with the set-side image processing device 710.

The image processing controller 200 further performs image processing (for example, image data correction processing) on the image data from the set-side image processing device 710 in order to perform overdrive drive compensation, and sends the image data to the source drivers 132 _{1 to} 132 _J. On the other hand, image data after image processing is supplied, and display timing signals are supplied to the source drivers 132 _{1 to} 132 _J and the gate drivers 122 _{1 to} 122 _K. Accordingly, the liquid crystal driving device 150 (source drivers 132 _{1 to} 132 _J ) can overdrive the display panel 110.

  The memory 144 is, for example, a RAM (Random Access Memory). In the memory 144, setting information of the image processing controller 200 is stored, and work data of the image processing controller 200 is stored. The image processing controller 200 can perform image processing corresponding to the setting information by reading the setting information stored in the memory 144.

The control board 140 is electrically connected to the source drivers 132 _{1 to} 132 _J of the data board 130 by a flexible cable. Note that the gate substrate 120 and the data substrate 130 can exchange signals by a film wiring (not shown) or the like.

  Accordingly, the liquid crystal driving device 150 scans a plurality of gate lines of the display panel 110, a source driver that drives the plurality of source lines of the display panel 110 based on image data, and an image for the source driver. It can be said that it includes an image processing controller that supplies the processed image data. The display module 100 also displays an image for the display panel 110, a source driver that drives a plurality of source lines of the display panel 110, a gate driver that scans the plurality of gate lines of the display panel 110, and the plurality of source drivers. It can be said that the image processing controller 200 that outputs data is included.

As described above, in the personal computer system 10, the image data generated by the host 700 is subjected to scale processing, overlay processing, and the like by the set-side image processing device 710. The image data after image processing by the set-side image processing device 710 is at least overdriven (image data correction processing for performing overdrive driving compensation) is performed by the image processing controller 200 via the I / F circuit 142. The processed image data is supplied to the source drivers 132 _{1 to} 132 _J. The source drivers 132 _{1 to} 132 _J cooperate with the gate drivers 122 _{1 to} 122 _K to drive the display panel 110 based on the image data.

  In FIG. 1, the memory 144 is described as being mounted on the control board 140, but the memory 144 may be built in the image processing controller 200 or the I / F circuit 142.

  By the way, in the MVA type display panel, a phenomenon in which the responsiveness of the liquid crystal is deteriorated due to the rebound phenomenon is known.

  FIG. 5 is an explanatory diagram of the rebound phenomenon in the present embodiment.

  In FIG. 5, the same parts as those in FIG.

  In the MVA type display panel, as shown in FIG. 3, when the applied voltage of the liquid crystal is not applied, the liquid crystal molecules LC1 to LC5 (more specifically, the major axis direction of the liquid crystal molecules LC1 to LC5) are liquid crystal layers. Is oriented in a direction perpendicular to the surface (the main surface of the TFT substrate, the main surface of the common substrate, the main surface of the pixel electrode, the main surface of the common electrode). When overdrive driving is performed from such a state of liquid crystal molecules, a high voltage is suddenly applied to the liquid crystal, and the liquid crystal molecules located near the pixel electrode (near the TFT substrate) and near the common electrode (near the common substrate) immediately Can react. In contrast, liquid crystal molecules located far from the pixel electrode (near the TFT substrate) and the common electrode (near the common substrate) can be tilted in either direction, and as a result, the liquid crystal molecules located near the electrode. Will respond later.

  For example, since the liquid crystal molecules LC1, LC2, LC4, and LC5 in FIG. 5 are located in the vicinity of the electrodes, they can respond at high speed, but the response of the liquid crystal molecules LC3 is delayed. This phenomenon appears as a slip-back phenomenon, and it becomes a cause that the image quality of the moving image cannot be improved even if overdrive driving is performed.

  FIG. 6 shows an example of the timing of the rebound phenomenon in this embodiment.

In the (j−1) th frame (j is an integer of 2 or more), a voltage corresponding to the gradation GV _j is applied to the liquid crystal in the jth frame, which is the next frame of the (j−1) th frame. in order to overdrive the source line by using the (j-1) th overdrive voltage corresponding to a difference dif between the gradation GV _j-1 and the gradation GV _j frames of the j-th frame of. As a result, the optical response is accelerated in the j-th frame.

  However, in the next (j + 1) th frame, the slip-back phenomenon occurs for the above reason, and the improvement of the image quality is hindered.

  Therefore, in order to improve the deterioration in image quality due to such a phenomenon of rebound, one frame is divided into N fields (N is a natural number of 2 or more, here N = 2). In the Mth field (M is a natural number smaller than N, where M = 1), it is conceivable to perform drive control to make overdrive stronger.

  FIG. 7 shows an example of the timing and display image when the above drive control is performed.

In the second field of the (j−1) th frame (j is an integer of 2 or more), the voltage corresponding to the gradation GV _j in the jth frame that is the next frame of the (j−1) th frame in order to be applied to the liquid crystal, by using the (j-1) th overdrive voltage corresponding to a difference dif gradation GV _j-1 and the gradation GV _j frames of the j-th frame of display gradation Overdrive the source line so as to overshoot the target gradation. As a result, in the first field of the j-th frame, the display gradation overshoots the target gradation, the optical response becomes fast, and the display gradation falls below the target gradation due to rebound ( (See FIG. 6).

  Further, when the display gradation is appropriately overshooted with respect to the target gradation in this way, the edge of the image is emphasized and the moving image looks sharp.

  However, when such drive control is performed, the tailing of the display image becomes long as shown in the lower part of FIG. Further, as shown in the upper part of FIG. 7, the display gradation may not be able to converge (reach) to the target gradation in the j-th frame. In particular, in the above-described MVA type liquid crystal panel and the like, the response speed is slow in the case of a gradation change from an intermediate gradation to an intermediate gradation, so that the display gradation converges to the target gradation in the jth frame. You may not be able to do it. As a result, blurring and tailing are emphasized, and the moving image quality is deteriorated.

  Therefore, in the present embodiment, one frame is divided into N fields (N is a natural number of 2 or more. In this embodiment, N = 2), and the liquid crystal layer is driven. A step of performing drive compensation, and the step of performing drive compensation is such that the display gradation exceeds the target gradation in the Mth field (M is a natural number smaller than N. Here, M = 1). The overdrive drive is performed so as to shoot, and the overdrive drive is performed in the polarity direction opposite to the overdrive in the Mth field in the (M + 1) th field.

  FIG. 8 shows an example of the timing and display image when the drive control as described above is performed.

  In the present embodiment, in the first field of the j-th frame, overdrive driving (here, overdrive driving to the high potential side) is performed so that the display gradation overshoots the target gradation. By doing this, the edges of the image are enhanced and the moving image looks sharp.

  In the second field of the j-th frame, overdrive is performed in the polarity direction opposite to the overdrive in the first field (here, overdrive is driven to the low potential side). In this way, as shown in the lower part of FIG. 8, the tailing of the display image can be shortened compared to the lower part of FIG. In addition, as shown in the upper part of FIG. 8, the display gradation can converge (reach) to the target gradation in the j-th frame. Thereby, blurring and tailing can be reduced.

  In addition, since the structure of the existing display panel 110 can be used, it is possible to improve the deterioration of image quality due to the rebound phenomenon at a very low cost.

2. In the present embodiment, overdrive driving is realized by correcting image data in the image processing controller 200. In this way, the existing source driver can be used and the cost can be reduced.

  FIG. 9 shows an example of a functional block diagram of the image processing controller 200 in the present embodiment.

  The image processing controller 200 can include an N double speed drive unit 210 (double speed drive means in a broad sense) and a drive compensation section 220 (drive compensation means in a broad sense).

The N-times speed driving unit 210 generates a clock signal OCLK and a data enable obtained by setting the clock signal ICLK and the data enable signal IDATAENAB supplied from the set-side image processing device 710 (see FIG. 1) to N-times speed (N is a natural number of 2 or more). A signal ODATAENAB is generated and output to the drive compensation unit 220 and the source drivers 132 _{1 to} 132 _J (see FIG. 1).

  The drive compensation unit 220 performs drive compensation when driving the liquid crystal layer of the display panel 110 (liquid crystal device). More specifically, the drive compensation unit 220 adds or subtracts a compensation value corresponding to the difference between the image data of the previous frame and the image data of the current frame (M is a natural number smaller than N). Corresponding to the (M + 1) th field image data obtained by applying a driving voltage corresponding to the field image data to the liquid crystal and adding or subtracting a compensation value corresponding to the difference between the image data of the previous frame and the image data of the current frame. Control is performed to apply the drive voltage thus applied to the liquid crystal.

  FIG. 10 shows a hardware configuration example of the image processing controller 200 of FIG.

The drive compensation unit 220 of the image processing controller 200 includes a memory 221, a comparator 222, a lookup table (LUT) 223, an LUT address generation circuit 224, an interpolation computation unit 225, and first and second field compensation computation units 226 ₁ , 226 _2. , A previous field data read circuit 227 and a frame data write circuit 228 are included.

  The previous field data read circuit 227 reads the image data of the previous field from the memory 144 in synchronization with the read clock generated by the N-times speed driving unit 210.

  The memory 221 buffers input image data (frame image data) IDAT (hereinafter also referred to as Dat) supplied from the set-side image processing device 710 (see FIG. 1). The memory 221 is provided to latch the input image data IDAT because the internal circuit of the drive compensation unit 220 operates at N times the input image data IDAT.

  The comparator 222 compares the input image data with the image data of the previous field buffered in the previous field data reading circuit 227. The comparison result of the comparator 222 is output to the compensation value interpolation calculation unit 225.

  In the LUT 223, compensation values to be compensated for driving corresponding to the input image data and the image data one field before are registered in advance.

  FIG. 11 is an explanatory diagram of registered values of the LUT 223 in FIG.

  In the LUT 223, for example, a plurality of compensation values of S (S is an integer of 2 or more) bits are registered. The upper bit (or lower bit) of each compensation value is a compensation value α for overdrive driving of the Mth field, and the lower bit (or upper bit) of each compensation value is overdrive driving of the (M + 1) th field. Is the compensation value β. Each such compensation value is specified by the LUT address assigned to the LUT 223. The LUT 223 outputs a compensation value corresponding to the LUT address.

  In the upper bits (or lower bits) of the LUT 223, the overdrive voltage increases as the difference between the image data of the jth frame (j is an integer of 2 or more) and the (j−1) th frame increases. In the field M, a compensation value for overdrive driving is registered so that the display gradation overshoots the target gradation. In the lower bit (or upper bit) of the LUT 223, a compensation value for overdrive driving in the opposite polarity direction to the overdrive in the Mth field in the (M + 1) th field is registered.

  The LUT address generation circuit 224 generates the LUT address so that the upper bit (or lower bit) is the image data of the previous field and the lower bit (or upper bit) is the input image data.

  Thus, based on the previous field and the input image data, the LUT 223 reads the M-th field overdrive driving compensation value and the (M + 1) th overdrive driving compensation value.

  In FIG. 10, the LUT address generation circuit 224 generates an address of the LUT 223 corresponding to the input image data and the image data of one field before, and reads the compensation value registered corresponding to the address from the LUT 223. .

The compensation value interpolation calculation unit 225 performs interpolation calculation of the compensation value read from the LUT 223 based on the comparison result signal from the comparator 222. More specifically, when it is detected from the comparison result signal from the comparator 222 that the input image data matches the image data of the previous field, the compensation value interpolation calculation unit 225 performs the compensation read from the LUT 223. Without performing the value interpolation calculation, the compensation value is output as it is to the first and second field compensation calculation units 226 ₁ and 226 ₂ .

When it is detected from the comparison result signal from the comparator 222 that the input image data does not match the image data of the previous field, the compensation value interpolation calculation unit 225 calculates the two compensation values read from the LUT 23. For each of them, linear interpolation processing calculation is performed according to the difference between the two image data, and the processed compensation values are output to the first and second field compensation calculation units 226 ₁ , 226 ₂ . The first field compensation calculation unit 226 _1, the compensation value alpha _n-1 of the M drive field overdrive is input, the second field compensation calculation unit 226 _2, over the field (M + 1) th A drive driving compensation value β _n−1 is input.

In the first field period of the n-th (n is a natural number equal to or greater than 2) frame, the first field compensation calculation unit 226 ₁ and the image data Dat (n) from the set-side image processing device 710 and the compensation value interpolation Addition / subtraction processing with the compensation value α (n) _1f (subscript “1f” represents the first field) after the interpolation calculation from the calculation unit 225 is performed, and the output image data ODAT (Dat (n) ± α ( n) Output as _1f ). Further, the first field compensation calculation unit 2261 ₁ performs the interpolation calculation from the image data Dat (n) from the set-side image processing device 710 and the compensation value interpolation calculation unit 225 in the second field period of the nth frame. The subsequent compensation value α (n) _2f (subscript “2f” represents the second field) is added and subtracted and output as output image data ODAT (Dat (n) ± α (n) _2f ). .

The second field compensation calculator 226 _2, in the first field period of the frame of the n, after interpolation calculation from image data Dat (n) and the compensation value interpolation operation unit 225 from the set-side image processing apparatus 710 _Addition / subtraction processing with the compensation value β (n) _1f is performed to generate processed image data Dat (n) ± β (n) _1f . The second field compensation calculator 226 _2, in the second field period of a frame of the n, interpolation calculation from image data Dat (n) and the compensation value interpolation operation unit 225 from the set-side image processing apparatus 710 _Addition / subtraction processing with the subsequent compensation value β (n) _2f is performed to generate processed image data Dat (n) ± β (n) _2f .

Write frame data write circuit 228, the first in the field period second field compensation calculation unit 226 _{and second} output _{Dat (n) ± β (n} ) 1f of the frame of the n, produced by the N double-speed driving portion 210 The data is written in the memory 144 in synchronization with the clock for use. The image data written by the frame data writing circuit 228 is read as previous field image data Dat (n) ± β (n) _1f in the second field of the nth frame. The frame data write circuit 228, the n-th second in field period second field compensation calculation section 226 _{and second} output _{Dat (n) ± β (n} ) 2f of the frame, is generated by the N double-speed driving portion 210 The data is written in the memory 144 in synchronization with the write clock. The image data written by the frame data writing circuit 228 is read as previous field image data Dat (n) ± β (n) _2f in the first field of the (n + 1) th frame.

  FIG. 12 shows an example of the operation timing of the image processing controller 200 of FIG.

  In FIG. 12, it is assumed that image data for driving the source line of the display panel 110 is generated in the nth frame. At this time, the image processing controller 200 divides the nth frame into two fields.

In the first field of the nth frame, the input image data Dat (n) is input from the memory 221 to the comparator 222, and the previous field data read circuit 227 receives the image data Dat (n) of the previous field from the memory 144. -1) Read out ± β (n-1) _2f . The comparator 222 compares both image data.

The LUT address generation circuit 224 generates a LUT address by concatenating the input image data Dat (n) and the image data Dat (n−1) ± β (n−1) _{2f of the} previous field, and a compensation value from the LUT 223. α (n) _1f and β (n) _1f are read out.

The first field compensation calculation unit 226 ₁ adds or subtracts the input image data Dat (n) and the compensation value α (n) _1f and outputs the result as image data ODAT. The voltage corresponding to the image data ODAT is a voltage in consideration of the overdrive driving voltage in the first field of the nth frame.

The second field compensation calculator 226 ₂ adds or subtracts the input image data Dat (n) and a compensation value beta _{(n) 1f,} the frame data write circuit 228, Dat (n) ± beta a _{(n) 1f} Buffer in memory 144. This Dat (n) ± β (n) _1f is read as previous field data in the second field of the nth frame.

In the second field of the nth frame, the previous field data read circuit 227 reads the image data Dat (n) ± β (n) _1f of the previous field from the memory 144. The comparator 222 compares the input image data Dat (n) with the image data Dat (n) ± β (n) _1f one field before.

The LUT address generation circuit 224 generates a LUT address by concatenating the input image data Dat (n) and the image data Dat (n) ± β (n) _{1f of the} previous field, and a compensation value α (n) from the LUT 223. _2f and β (n) _2f are read out.

The first field compensation calculator 226 _1, the compensation value α _{(n) 2f} and adding or subtracting the input image data Dat (n), and outputs the image data ODAT. The voltage corresponding to the image data ODAT is a voltage in consideration of the overdrive driving voltage in the second field of the nth frame.

The second field compensation calculator 226 ₂ adds or subtracts the input image data Dat (n) and a compensation value beta _{(n) 2f,} the frame data write circuit 228, Dat (n) ± beta a _{(n) 2f} Buffer in memory 144. This Dat (n) ± β (n) _2f is read as previous field data in the first field of the (n + 1) th frame.

  FIG. 13 shows an example of the drive voltage and optical response of the display panel 110 in this embodiment.

  FIG. 13 shows an example of a change in gradation, a change in drive voltage, and a change in optical response, focusing on the overdrive drive performed in the nth frame.

  When the gradation is switched from the (n−1) th frame to the nth frame, in the first field of the nth frame, the image data of the second field of the (n−1) th frame and the Corresponding to the difference from the image data of the first field of the n frame, a drive voltage (here, overdrive to the high potential side) with an overdrive voltage added so that the display gradation overshoots the target gradation. The driven drive voltage) is applied to the liquid crystal of the display panel 110, and overdrive drive is performed. As a result, as shown in the response Resp1 in FIG. 13, the optical response changes so as to overshoot the target gradation in the first field of the nth frame.

  Next, in the second field of the nth frame, corresponding to the difference between the image data of the first field of the nth frame and the image data of the second field of the nth frame, A driving voltage in which the overdrive voltage is added in the opposite polarity direction to the overdrive in the first field of the frame (here, the drive voltage overdriven to the low potential side) is applied to the liquid crystal of the display panel 110, Overdrive drive is performed. As a result, the optical response is speeded up as shown by the response Resp2 in FIG.

  Then, after the (n + 1) th frame, the drive voltage is returned to the original gradation voltage corresponding to the original image data.

  Although attention is paid to the overdrive drive in the nth frame in FIG. 13, in actuality, the voltage for overdrive drive is applied to each frame in a pipeline manner.

As described above, the image processing controller 200 according to the present embodiment divides one frame into N fields (N is a natural number of 2 or more), and in the M-th field (M is a natural number smaller than N). Overdrive driving is performed so that the display gradation overshoots the target gradation, and in the (M + 1) th field, overdrive driving is performed in the polarity direction opposite to that in the Mth field. More specifically, the image processing controller 200 corrects the images in the first and second fields of the nth frame for each dot based on the difference between the image data of the nth and (n−1) th frames. can do. As a result, the source drivers 132 _{1 to} 132 _J can apply a driving voltage corresponding to the corrected image data to the liquid crystal layer.

  As a result, when the frame rate is a general 60 fps, a response in one field period (about 8 ms) can be realized.

  In the above embodiment, an example in which one frame is divided into two fields has been described. However, one frame may be divided into three or more fields. In this case, in the first field, the overdrive drive is performed so that the display gradation overshoots the target gradation, and in the second field, the overdrive drive is performed in the polarity direction opposite to the overdrive in the first field. In the second (or later) field, overdrive is performed so that the display gradation overshoots the target gradation, and the second (or later) field may be used. In the field, overdrive driving may be performed in the polarity direction opposite to the overdrive in the second field.

  Further, the present embodiment may be combined with other technologies related to the liquid crystal device. For example, by combining the scan type backlight and the present embodiment, the backlight is turned off while the optical response is rapidly changing in the first field, and the backlight is turned on when the optical response is stabilized in the second field. You may make it turn on. By doing so, the moving image characteristics can be further improved.

3. Others The display module in the present embodiment is not limited to the configuration shown in FIG.

  FIG. 14 shows another configuration example of the display module in the present embodiment.

  14, the same parts as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

The display module in FIG. 14 is different from the display module in FIG. 1 in that the data board (control board) is omitted, and the source drivers 132 _{1 to} 132 _J , the image processing controller 200, the memory 144, and the I / F circuit 142 are one. It is a point mounted on the board. By doing so, the display module 100 can be miniaturized.

  Although the present embodiment has been described in detail as described above, it will be easily understood by those skilled in the art that many modifications can be made without departing from the novel matters and effects of the present invention. Accordingly, all such modifications are intended to be included in the scope of the present invention. For example, a term described at least once together with a different term having a broader meaning or the same meaning in the specification or the drawings can be replaced with the different term in any part of the specification or the drawings. Further, the configuration of the image processing controller, the overdrive driving voltage calculation method, and the like are not limited to those described in the present embodiment, and various modifications can be made.

  In the invention according to the dependent claims of the present invention, a part of the constituent features of the dependent claims can be omitted. Moreover, the principal part of the invention according to one independent claim of the present invention can be made dependent on another independent claim.

FIG. 10 is a diagram illustrating a configuration example of an electronic device to which the liquid crystal device according to the embodiment is applied. FIG. 2 is a diagram illustrating an example of an equivalent circuit of a pixel of the display panel in FIG. 1. The figure which shows typically the cross-section of the display panel in this embodiment. The figure which shows the outline | summary of a structure of a display panel. Explanatory drawing of the rebound phenomenon in this embodiment. The figure which shows an example of the timing of the rebound phenomenon in this embodiment. The figure which shows an example of the timing of the drive control of a display panel. The figure which shows an example of the timing of the drive control of the display panel of this embodiment. FIG. 3 is a diagram illustrating an example of functional blocks of an image processing controller in the present embodiment. The figure which shows the hardware structural example of the image processing controller of FIG. FIG. 11 is an explanatory diagram of registered values of the LUT in FIG. FIG. 11 is a diagram illustrating an example of operation timing of the image processing controller in FIG. 10. The figure which shows an example of the drive voltage and optical response of the display panel in this embodiment. The figure which shows the other structural example of the display module in this embodiment.

Explanation of symbols

10 personal computer system, 100 display module,
110 display panel, 120 gate substrate, 122 _{1 to} 122 _K gate driver,
130 data board, ₁₃₂ 1 to 132 _J source driver,
140 control board, 142 I / F circuit, 144 memory,
150 liquid crystal drive device, 200 image processing controller, 210 N double speed drive unit,
220 drive compensation unit, 221 memory, 222 comparator, 223 LUT,
224 LUT address generation circuit, 225 compensation value interpolation calculation unit,
226 ₁ The first field compensation calculation unit, 226 ₂ second field compensation calculation unit,
227 Previous field data read circuit,
228 frame data writing circuit, 700 host,
710 Set-side image processing device

Claims (10)

A liquid crystal driving device for driving a liquid crystal device,
Double speed driving means for dividing one frame into N (N is a natural number of 2 or more) fields;
Drive compensation means for performing drive compensation when driving the liquid crystal layer of the liquid crystal device;
Including
The drive compensation means;
In the Mth field (M is a natural number smaller than N) among the N fields, the display grayscale is overdriven so that the display grayscale overshoots the target grayscale, and the Nth field among the N fields is driven. In the (M + 1) field, the liquid crystal drive device is characterized in that overdrive is performed in a polarity direction opposite to that of the overdrive drive in the Mth field. In claim 1,
When driving compensation is performed on a j-th frame (j is a natural number of 2 or more),
The second means comprises:
The image data of the Mth and (M + 1) th frames is corrected for each dot based on the difference between the image data of the jth and (j−1) th frames, and an overdrive voltage corresponding to the image data is obtained. A liquid crystal drive device, wherein the liquid crystal layer is applied to the liquid crystal layer. In claim 1 or 2,
The second means comprises:
The overdrive voltage is applied to the liquid crystal layer such that the larger the difference between the image data of the jth and (j−1) th frames, the greater the overdrive voltage in the Mth field. Liquid crystal drive device. In any one of Claims 1 thru | or 3,
The liquid crystal device is
A liquid crystal driving device comprising a liquid crystal layer that forms a plurality of domains and operates in a vertical alignment mode. A liquid crystal device having a liquid crystal layer that forms a plurality of domains and operates in a vertical alignment mode,
A first electrode to which a driving voltage corresponding to gradation data is applied;
A second electrode to which a given common voltage is applied;
The liquid crystal layer sandwiched between the first and second electrodes;
The liquid crystal driving device according to claim 4, wherein the liquid crystal driving device drives the first electrode.
A liquid crystal device comprising: A backlight for supplying light to the liquid crystal layer;
A backlight control device for controlling the backlight;
Further including
The backlight control device is
The liquid crystal device, wherein the backlight is controlled to be turned off in the Mth field, and the backlight is controlled to be turned on in the (M + 1) field. A method of driving a liquid crystal device,
Dividing one frame into N (N is a natural number of 2 or more) fields;
Performing drive compensation when driving the liquid crystal layer of the liquid crystal device;
Including
Performing the drive compensation comprises:
In the Mth field (M is a natural number smaller than N) among the N fields, the display grayscale is overdriven so that the display grayscale overshoots the target grayscale, and the Nth field among the N fields is driven. In the field of (M + 1), overdrive driving is performed in a polarity direction opposite to that of the overdrive driving in the Mth field. In claim 7,
When driving compensation is performed on a j-th frame (j is a natural number of 2 or more),
The image data of the Mth and (M + 1) th frames is corrected for each dot based on the difference between the image data of the jth and (j−1) th frames, and an overdrive voltage corresponding to the image data is obtained. A method for driving a liquid crystal device, wherein the liquid crystal layer is applied to the liquid crystal layer. In claim 7 or 8,
The overdrive voltage is applied to the liquid crystal layer such that the larger the difference between the image data of the jth and (j−1) th frames, the greater the overdrive voltage in the Mth field. A driving method of a liquid crystal device. In any one of Claims 7 thru | or 9,
The liquid crystal device is
A driving method of a liquid crystal device, comprising a liquid crystal layer that forms a plurality of domains and operates in a vertical alignment mode.