Liquid crystal display device, control method for liquid crystal display device, and electronic device.

Abstract

Minimizes display conflicts in discrimination correction. [Solution] The display control circuit 20 applies a first correction to the pixel data of an image pixel based on the pixel data of two or more surrounding image pixels. After the first correction, it determines whether both the voltage corresponding to the gradation level of the pixel data of the image pixel of interest and the voltage corresponding to the gradation level of the pixel data of the image pixel adjacent to the image pixel of interest are within the range of intermediate gradation. If both voltages are within the range of intermediate gradation, it applies a second correction to cancel out the first correction applied to the pixel data of the image pixel of interest, and supplies a data signal to the panel pixels based on the pixel data after the first correction, or, if the second correction has been applied, the pixel data after the second correction.

Description

Technical Field

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[0001] The present invention relates to a liquid crystal display device, a control method of the liquid crystal display device, and an electronic device.

Background Art

[0002] As miniaturization and high definition of liquid crystal panels have progressed in recent years, the gap between pixel electrodes has become narrower, and the influence of the electric field generated between adjacent pixel electrodes, that is, the electric field (horizontal electric field) parallel to the substrate surface, cannot be ignored. Specifically, due to the horizontal electric field, an alignment defect of liquid crystal molecules called disclination occurs and is visually recognized as a display defect. Therefore, when it is predicted that the horizontal electric field becomes strong and display defects due to disclination are visually recognized, a technique has been proposed in which video data supplied from a host device is corrected so that the difference in voltage applied to adjacent pixel electrodes becomes small. Such correction is sometimes called disclination correction or domain correction (see, for example, the description of Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in disclination correction such as the above technique, correcting the video data supplied from the host device means that display according to the video data is not performed, and there is a problem that so-called display contradiction occurs.

Means for Solving the Problems

[0005] A liquid crystal display according to one aspect of the present disclosure includes a liquid crystal panel having panel pixels and a display control circuit for controlling the liquid crystal panel, wherein the gradation level of the image pixels constituting the image data is specified by pixel data, the image pixels include a first image pixel and a first adjacent image pixel adjacent to the first image pixel, the display control circuit supplies a voltage data signal to a panel pixel corresponding to the first image pixel based on the gradation level specified by the pixel data of the first image pixel, and supplies a voltage data signal to a panel pixel corresponding to the first adjacent image pixel based on the gradation level specified by the pixel data of the first adjacent image pixel A voltage data signal based on a threshold is supplied, and when both the gradation level specified by the pixel data of the first video pixel and the gradation level specified by the pixel data of the first adjacent video pixel are within the range of intermediate gradations, which is between a first threshold gradation and a second threshold gradation, the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel is made different from the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel when at least one of the gradation level of the first video pixel or the gradation level of the first adjacent video pixel is outside the range of intermediate gradations.

[0006] A liquid crystal display device according to another embodiment includes a liquid crystal panel having panel pixels and a display control circuit for controlling the liquid crystal panel, wherein the image pixels constituting the image data are arranged in a first direction and a second direction, the gradation level of the image pixels is specified by pixel data, and the display control circuit applies a first correction to the pixel data of one image pixel based on the pixel data of two or more adjacent image pixels in the first direction, the direction opposite to the first direction, the second direction, or the direction opposite to the second direction, and among the pixel data after the first correction, the image pixel of interest is selected. The system determines whether both the voltage corresponding to the grayscale level of the pixel data of the image pixel of interest and the voltage corresponding to the grayscale level of the pixel data of an image pixel adjacent to the image pixel of interest in either the first or second direction are within a first range. If both voltages are within the intermediate grayscale range between a first threshold voltage and a second threshold voltage, a second correction is applied to cancel out the first correction applied to the pixel data of the image pixel of interest. A data signal based on the pixel data after the first correction, or, if the second correction has been applied, the pixel data after the second correction, is then supplied to the panel pixel.

[0007] A control method for a liquid crystal display device according to another embodiment includes a liquid crystal panel having panel pixels and a display control circuit for controlling the liquid crystal panel, wherein the gradation level of the image pixels constituting the image data is specified by pixel data, and the image pixels include a first image pixel and a first adjacent image pixel adjacent to the first image pixel, and a voltage data signal based on the gradation level specified by the pixel data of the first image pixel is supplied to the panel pixel corresponding to the first image pixel, and a control method based on the gradation level specified by the pixel data of the first adjacent image pixel is supplied to the panel pixel corresponding to the first adjacent image pixel. A data signal of a certain voltage is supplied, and when both the gradation level specified by the pixel data of the first video pixel and the gradation level specified by the pixel data of the first adjacent video pixel are within the range of intermediate gradations, which is between a first threshold gradation and a second threshold gradation, the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel is made different from the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel when at least one of the gradation level of the first video pixel or the gradation level of the first adjacent video pixel is outside the range of intermediate gradations. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows a projection-type display device to which the liquid crystal display device according to the first embodiment is applied. [Figure 2] This is a block diagram showing the configuration of a projection display device. [Figure 3] This is a perspective view showing the configuration of a liquid crystal panel in a projection display device. [Figure 4] This is a cross-sectional view showing the structure of a liquid crystal panel. [Figure 5] This block diagram shows the electrical configuration of an LCD panel. [Figure 6] This diagram shows the configuration of the pixel circuit in a liquid crystal panel. [Figure 7] This is a block diagram showing the configuration of a processing circuit in a projection-type display device. [Figure 8] This figure shows an example of VT characteristics in a liquid crystal element. [Figure 9]This is a diagram for explaining disclination in a liquid crystal panel. [Figure 10] This is a diagram showing an example of a filter coefficient of a smoothing circuit in a processing circuit. [Figure 11] This is a diagram showing an example before and after application of a smoothing circuit in a video pixel. [Figure 12] This is a diagram showing an example of a two-dimensional table of a restoration circuit in a processing circuit. [Figure 13] This is a diagram for explaining the operation of a processing circuit. [Figure 14] This is a diagram for explaining the operation of a processing circuit. [Figure 15] This is a diagram for explaining the operation of a processing circuit. [Figure 16] This is a flowchart showing the operation of a processing circuit. [Figure 17] This is a diagram showing the configuration of a processing circuit in a liquid crystal display device according to the first embodiment. [Figure 18] This is a diagram for explaining the operation of a processing circuit. [Figure 19] This is a diagram for explaining the operation of a processing circuit. [Figure 20] This is a diagram for explaining the operation of a processing circuit. [Figure 21] This is a flowchart showing the operation of a processing circuit.

Embodiments for Carrying Out the Invention

[0009] Hereinafter, a liquid crystal display device according to an embodiment will be described with reference to the drawings. In each figure, the dimensions and scales of each part are appropriately different from the actual ones. Further, the embodiments described below are preferred specific examples, and thus various technically preferable limitations are imposed. However, the scope of the present disclosure is not limited to these embodiments unless there is a description specifically limiting the present disclosure in the following description.

[0010] FIG. 1 is a diagram showing the optical configuration of a projection display device 1 according to an embodiment. As shown in the figure, the projection display device 1 includes liquid crystal panels 100R, 100G, and 100B. Inside the projection display device 1, a lamp unit 2102 composed of a white light source such as a halogen lamp or an LED is provided. The white light emitted from this lamp unit 2102 is separated into three primary colors of red (R), green (G), and blue (B) by three mirrors 2106 and two dichroic mirrors 2108 arranged inside. Among these, the R light is incident on the liquid crystal panel 100R, the G light is incident on the liquid crystal panel 100G, and the B light is incident on the liquid crystal panel 100B, respectively. Note that since the optical path of B is longer than those of R and G, it is necessary to prevent losses in the optical path of B. For this reason, a relay lens system 2121 composed of an incident lens 2122, a relay lens 2123, and an exit lens 2124 is provided in the optical path of B.

[0011] The liquid crystal panel 100R has pixel circuits arranged in a matrix as will be described later. The transmittance of the light emitted from the liquid crystal elements in the pixel circuits is controlled based on the data signal corresponding to R. That is, in the liquid crystal panel 100R, the light emitted from the liquid crystal elements functions as the minimum unit of the image. By such control, the liquid crystal panel 100R generates a transmitted image of R based on the data signal corresponding to R. Similarly, the liquid crystal panel 100G generates a transmitted image of G based on the data signal corresponding to G, and the liquid crystal panel 100B generates a transmitted image of B based on the data signal corresponding to B.

[0012] The transmitted images of each color generated by the liquid crystal panels 100R, 100G, and 100B are incident on the dichroic prism 2112 from three directions. In the dichroic prism 2112, the R and B lights are refracted at 90 degrees, while the G light travels straight. Therefore, the dichroic prism 2112 synthesizes the images of each color. The synthesized image by the dichroic prism 2112 is incident on the projection lens 2114. The projection lens 2114 enlarges and projects the synthesized image by the dichroic prism 2112 onto the screen Scr.

[0013] Furthermore, the transmitted images from liquid crystal panels 100R and 100B are projected after being reflected by the dichroic prism 2112, whereas the transmitted image from liquid crystal panel 100G is projected in a straight line. Therefore, the transmitted images from liquid crystal panels 100R and 100B are horizontally inverted relative to the transmitted image from liquid crystal panel 100G.

[0014] Figure 2 is a block diagram showing the electrical configuration of the projection display device 1. As shown in the figure, the projection display device 1 includes a display control circuit 20 and the liquid crystal panels 100R, 100G, and 100B described above.

[0015] The display control circuit 20 receives video data Vid_in from a higher-level device, such as a host device (not shown), synchronized with the synchronization signal Sync. The video data Vid_in is data indicating the image to be displayed on the projection display device 1, and in detail, in this embodiment, the gradation level of each pixel of the image is specified using 8 bits for each RGB component.

[0016] In this embodiment, the pixels of an image specified by the video data Vid_in or the correction data for said video data are referred to as video pixels, and the data specifying the gradation level of the video pixels is referred to as pixel data. However, video pixels and pixel data are sometimes explained without making a particular distinction. In addition, pixels before or after synthesis by the liquid crystal panel 100R, 100G, or 100B are referred to as panel pixels. In cases where there is a one-to-one correspondence between video pixels and panel pixels, as in this embodiment, there is no need to make a particular distinction between video pixels and panel pixels. The Sync synchronization signal includes a vertical synchronization signal that instructs the start of vertical scanning in the video data Vid_in, a horizontal synchronization signal that instructs the start of horizontal scanning, and a clock signal that indicates the timing of one pixel of the video data.

[0017] In this embodiment, the color image projected onto the screen Scr is represented by superimposing the transmitted images of the liquid crystal panels 100R, 100G, and 100B. Therefore, the smallest unit of the color image, the pixel, can be divided into red panel pixels from liquid crystal panel 100R, green panel pixels from liquid crystal panel 100G, and blue panel pixels from liquid crystal panel 100B. Strictly speaking, the red, green, and blue panel pixels should be referred to as sub-pixels, but in this explanation, they will be referred to as panel pixels as described above.

[0018] The display control circuit 20 includes a control circuit 21, and processing circuits 22R, 22G, and 22B. The control circuit 21 generates a control signal Ctr for controlling the liquid crystal panels 100R, 100G, and 100B. Details of processing circuits 22R, 22G, and 22B will be described later, but processing circuit 22R processes the R component video data Va_R of the video data Vid_in, converts it into an analog data signal Vid_R, and supplies it to the liquid crystal panel 100R. Similarly, processing circuit 22G processes the G component video data Va_G from the video data Vid_in, converts it into an analog data signal Vid_G, and supplies it to the liquid crystal panel 100G. Processing circuit 22B processes the B component video data Va_B from the video data Vid_in, converts it into an analog data signal Vid_B, and supplies it to the liquid crystal panel 100B.

[0019] Furthermore, a liquid crystal display device is defined as comprising a liquid crystal panel 100R, 100G, or 100B and a display control circuit 20 that supplies data signals to the liquid crystal panel.

[0020] Next, we will describe the liquid crystal panels 100R, 100G, and 100B. The liquid crystal panels 100R, 100G, and 100B differ only in the color of the incident light, i.e., the wavelength; structurally, they are identical. Therefore, when describing the liquid crystal panels 100R, 100G, and 100B generally without specifying the color, we will use the designation 100.

[0021] Figure 3 shows the main parts of the liquid crystal panel 100, and Figure 4 is a cross-sectional view taken along the Hh line in Figure 3. As shown in these figures, in the liquid crystal panel 100, an element substrate 100a on which pixel electrodes 118 are provided and a counter substrate 100b on which common electrodes 108 are provided are bonded together with a sealing material 90 so that their electrode-forming surfaces face each other while maintaining a certain gap, and liquid crystal 105 is sealed in this gap.

[0022] The element substrate 100a and the opposing substrate 100b are made of light-transmitting substrates such as glass or quartz, respectively. As shown in Figure 3, one side of the element substrate 100a extends beyond the opposing substrate 100b. Multiple terminals 106 are provided along the transverse direction in the figure in this extended region. One end of an FPC (Flexible Printed Circuits) substrate, not shown, is connected to these multiple terminals 106. The other end of the FPC substrate is connected to the display control circuit 20, to which the various signals described above are supplied.

[0023] On the element substrate 100a, the pixel electrode 118 is formed on the surface facing the opposing substrate 100b by patterning a transparent conductive layer, such as ITO (Indium Tin Oxide).

[0024] Figure 5 is a block diagram showing the electrical configuration of the liquid crystal panel 100. The liquid crystal panel 100 is provided with a scan line drive circuit 130 and a data line drive circuit 140 around the periphery of the display area 10.

[0025] In the display area 10 of the liquid crystal panel 100, pixel circuits 110 are arranged in a matrix. More specifically, in the display area 10, multiple scan lines 12 are provided extending in the horizontal X direction in the figure, and multiple data lines 14 are provided extending in the vertical Y direction, maintaining electrical isolation from the scan lines 12. The pixel circuits 110 are then arranged in a matrix corresponding to the intersections of the multiple scan lines 12 and the multiple data lines 14.

[0026] If the number of scan lines 12 is m and the number of data lines 14 is n, the pixel circuits 110 are arranged in a matrix with m rows and n columns. Both m and n are integers greater than or equal to 2. In the scan lines 12 and pixel circuits 110, the rows of the matrix are sometimes referred to as 1, 2, 3, ..., (m-1), and m rows from top to bottom in the diagram. Similarly, in the data lines 14 and pixel circuits 110, the columns of the matrix are sometimes referred to as 1, 2, 3, ..., (n-1), and n columns from left to right in the diagram.

[0027] The scan line driving circuit 130 selects scan lines 12 one by one in the order of, for example, the 1st, 2nd, 3rd, ..., mth row, according to the control of the display control circuit 20, and sets the scan signal to the selected scan line 12 to the H level. The scan line driving circuit 130 also sets the scan signal to the scan lines 12 other than the selected scan line 12 to the L level. The data line driving circuit 140 latches one line of data signals supplied from the corresponding color circuit among the processing circuits 22R, 22G, or 22B, and outputs to the pixel circuit 110 located on the scan line 12 via the data line 14 during the period when the scan signal to the scan line 12 is at a high level.

[0028] Figure 6 shows the equivalent circuits of the pixel circuits 110, consisting of four pixels arranged in two vertical rows and two horizontal columns, corresponding to the intersections of two adjacent scan lines 12 and two adjacent data lines 14. As shown in the figure, the pixel circuit 110 includes a transistor 116 and a liquid crystal element 120. The transistor 116 is, for example, an n-channel thin-film transistor. In the pixel circuit 110, the gate node of the transistor 116 is connected to the scan line 12, its source node is connected to the data line 14, and its drain node is connected to a pixel electrode 118 that is approximately square in plan view.

[0029] A common electrode 108 is provided for all pixels, facing the pixel electrode 118. A voltage LCcom is applied to the common electrode 108. Then, as described above, liquid crystal 105 is sandwiched between the pixel electrode 118 and the common electrode 108. Therefore, for each pixel circuit 110, a liquid crystal element 120 is formed, with the liquid crystal 105 sandwiched between the pixel electrode 118 and the common electrode 108. Furthermore, a storage capacitor 109 is provided in parallel with the liquid crystal element 120. One end of the storage capacitor 109 is connected to the pixel electrode 118, and the other end is connected to the capacitance line 107. A voltage constant over time, for example, the same voltage LCcom as the voltage applied to the common electrode 108, is applied to the capacitance line 107. The pixel circuit 110 is arranged in a matrix across the X direction, which is the direction in which the scan lines 12 extend, and the Y direction, which is the direction in which the data lines 14 extend. Therefore, the pixel electrodes 118 included in the pixel circuit 110 are also arranged across the X and Y directions.

[0030] When the scanning signal reaches the H level on scan line 12, the transistor 116 of the pixel circuit 110, which is provided in conjunction with that scan line 12, turns ON. When transistor 116 is ON, the data line 14 and the pixel electrode 118 are electrically connected, so the data signal supplied to the data line 14 reaches the pixel electrode 118 via the ON transistor 116. When scan line 12 reaches the L level, transistor 116 turns OFF, but the voltage of the data signal that reached the pixel electrode 118 is maintained by the capacitive and storage capacitance 109 of the liquid crystal element 120.

[0031] As is well known, in the liquid crystal element 120, the orientation of the liquid crystal molecules changes in response to the electric field generated by the pixel electrode 118 and the common electrode 108. Therefore, the transmittance of the liquid crystal element 120 corresponds to the effective value of the applied voltage. Furthermore, the region in the liquid crystal element 120 that functions as a panel pixel, that is, the region where the transmittance corresponds to the effective value of the voltage, is the region where the pixel electrode 118 and the common electrode 108 overlap when the element substrate 100a and the opposing substrate 100b are viewed in plan view. Since the pixel electrode 118 is approximately square in plan view, the shape of the pixel in the liquid crystal panel 100 is also approximately square.

[0032] Furthermore, in this embodiment, the liquid crystal 105 is a VA (Vertical Alignment) type, and is in a normally black mode where the transmittance is lowest when the applied voltage to the liquid crystal element 120 is zero, and the transmittance increases as the applied voltage increases.

[0033] The operation of supplying data signals to the pixel electrodes 118 of the liquid crystal element 120 is performed in the order of row 1, 2, 3, ..., m row during each horizontal scanning period. As a result, a voltage corresponding to the data signal is maintained in each of the liquid crystal elements 120 of the pixel circuit 110 arranged in m rows and n columns, so that each liquid crystal element 120 reaches the desired transmittance, and a transmitted image of the corresponding color is generated by the liquid crystal elements 120 arranged in m rows and n columns. In this way, the transmission image is generated for each RGB channel, and the resulting color image, created by combining the RGB channels, is projected onto the screen (Scr).

[0034] Next, we will describe the processing circuits 22R, 22G, and 22B shown in Figure 2.

[0035] Figure 7 is a block diagram showing the configurations of processing circuits 22R, 22G, and 22B. As shown in the figure, the processing circuit 22R includes a smoothing circuit 221R and a restoration circuit 223R. The smoothing circuit 221R smooths the R component video data Va_R using filter coefficients described later, so as to reduce the gradation level of adjacent video pixels. The restoration circuit 223R analyzes the video data whose gradation levels have been smoothed by the smoothing circuit 221R. If the gradation levels of two adjacent video pixels are within the range of intermediate gradations, it cancels out the smoothing of the gradation levels by the smoothing circuit 221R and restores (recovers) the original gradation levels.

[0036] Furthermore, the smoothing circuit 221G and the restoration circuit 223G, as well as the smoothing circuit 221B and the restoration circuit 223B, differ only in the color components of the video data they process; their circuit configurations are, in order, the same as those of the smoothing circuit 221R and the restoration circuit 223R. In other words, the smoothing circuit 221G and the restoration circuit 223G process the G component video data Va_G, and the smoothing circuit 221G and the restoration circuit 223B process the B component video data Va_B. In the following description of processing circuits 22R, 22G, and 22B without specifying the color components, the symbols for processing circuits will be 22, smoothing circuits 221, and restoration circuits 223.

[0037] The reason for smoothing the gradation levels by the smoothing circuit 221 will be explained.

[0038] Figure 8 shows an example of the voltage-transmittance characteristics (VT characteristics) applied to the liquid crystal element 120 in normally black mode. In normally black mode, when a high gradation level is specified and the transmittance is high for panel pixels, the voltage applied to the liquid crystal element 120 increases. On the other hand, when a low gradation level is specified and the transmittance is low for panel pixels, the voltage applied to the liquid crystal element 120 decreases.

[0039] For convenience, in order to explain discrimination, a panel pixel where the applied voltage to the liquid crystal element 120 is VH or higher and the transmittance is Thr is defined as a bright panel pixel. Conversely, a panel pixel where the applied voltage to the liquid crystal element 120 is VL or lower and the transmittance is Trl is defined as a dark panel pixel. Regarding VH and VL, VH>VL They are in a relationship.

[0040] As shown in Figure 9, in the liquid crystal panel 100, when bright panel pixels L with high transmittance, i.e., high voltage applied to the liquid crystal element 120, and dark panel pixels D with low transmittance, i.e. low voltage applied to the liquid crystal element 120, are adjacent, the voltage difference between the pixel electrodes 118 becomes large. When the voltage difference between the pixel electrodes 118 becomes large, the transverse electric field generated in the direction along the substrate surface becomes large, and a phenomenon called disclination, in which the orientation of liquid crystal molecules is disrupted, is more likely to occur in the region Dis that includes the boundary between the two panel pixels. Since the transmittance in the region Dis where disclination occurs does not correspond to the grayscale level, it becomes a factor that degrades the display quality.

[0041] To suppress display defects caused by discriminatives, a configuration can be considered that corrects the difference in gradation levels between adjacent image pixels to reduce the voltage difference between the pixel electrodes of adjacent panel pixels. The smoothing circuit 221 is configured for this purpose. The smoothing circuit 221 stores the corresponding color component video data for one frame in its internal memory and smooths the gradation levels of adjacent video pixels, for example, using filter coefficients.

[0042] Figure 10 shows an example of a matrix of filter coefficients (kernels) used in the convolution operation in the smoothing circuit 221. Using the filter coefficients shown in the diagram, the video data is processed as follows: In the array of video pixels that make up the video data, if we focus on a particular video image, and the gradation level of that focused video pixel is higher than that of the surrounding video pixels, the gradation level of that focused video pixel is multiplied by the coefficient shown in the thick frame to decrease it, and the gradation levels of the video pixels located around that focused video pixel are increased by a coefficient corresponding to their position. Conversely, if the gradation level of the focused video pixel is lower than that of the surrounding video pixels, the gradation level of that focused video pixel is multiplied by the coefficient shown in the thick frame to increase it, and the gradation levels of the video pixels located around that focused video pixel are decreased by a coefficient corresponding to their position.

[0043] Figure 11 shows examples of video pixels before smoothing and after smoothing, as shown in the video data. In the figure, the grayscale level of the video pixels is indicated by shades of gray.

[0044] In the smoothing circuit 221, when the gradation level of a selected image pixel is black and the image pixels surrounding that image pixel are white (display of black text on a white background), a correction is made in which the gradation level of the black image pixel in question is greatly increased, and the gradation level of the white image pixels surrounding it is greatly decreased. In other words, when a black image pixel and a white image pixel are adjacent, if there are fewer black image pixels than white image pixels, a relatively weak correction is applied to the white image pixels, and a relatively strong correction is applied to the black image pixels.

[0045] A black image pixel is defined as one where the gradation level, specified in 8 bits, is the lowest decimal value of "0," while a white image pixel is defined as one where the gradation level is the highest decimal value of "255." Here, the case where a single image pixel of interest has a black gradation level, and many image pixels with a white gradation level are located around it, including adjacent image pixels, is referred to as displaying black text on a white background. However, the case of displaying black text on a white background is not limited to this, and also includes cases where a single image pixel of interest has a low (dark) gradation level, and many image pixels with a high (bright) gradation level are located around it, including adjacent image pixels. Therefore, a white background with black text specifically refers to a display where relatively bright image pixels form the background, and relatively dark image pixels are used to represent lines, symbols, characters, etc.

[0046] On the other hand, when the gradation level of the image pixel in question is white, and the image pixels surrounding that image pixel are black (white text on a black background), a correction is applied that significantly reduces the gradation level of the white image pixel in question and slightly increases the gradation level of the black image pixels surrounding it. In other words, when black image pixels and white image pixels are adjacent, if there are more black image pixels than white image pixels, a relatively strong correction is applied to the white image pixels, and a relatively weak correction is applied to the black image pixels. Here, the case where a pixel of interest with a white grayscale level is surrounded by many pixels with a black grayscale level, including adjacent pixels, is referred to as displaying white text on a black background. However, the case of displaying white text on a black background is not limited to this, and also includes cases where a pixel of interest with a high grayscale level (bright) is surrounded by many pixels with a low grayscale level (dark), including adjacent pixels. Therefore, a black background with white text specifically refers to a display where relatively bright image pixels are arranged to represent text or other elements against a background of relatively dark image pixels.

[0047] In smoothing of gradation levels by such a smoothing circuit 221, display inconsistencies are likely to become a problem when the gradation levels of the image pixels are within the range of intermediate gradations. When they are within the range of intermediate gradations, the difference in gradation levels is small to begin with, but smoothing further reduces the difference in gradation levels, which can be perceived as blurring. Therefore, a restoration circuit 223 is provided that performs restoration processing to prevent display inconsistencies within the range of intermediate gradations.

[0048] The intermediate grayscale range referred to here is the range where the grayscale level is L_th1 or higher and L_th2 or lower. Both L_th1 and L_th2 are threshold grayscale levels, and when converted to decimal values, 0 <L_th1<L_th2<255 They have a relationship. When the range of intermediate grayscale tones is converted into the voltage applied to the liquid crystal element 120, the threshold grayscale L_th1 corresponds to the voltage V_th1, and the threshold grayscale L_th2 corresponds to the voltage V_th2. In other words, when the gradation level is converted to the voltage applied to the liquid crystal element 120, for example, if the applied voltage corresponding to a black image pixel is 0V and the applied voltage corresponding to a white image pixel is 5V, then in terms of voltage, 0 <V_th1<V_th2<5 They have a relationship.

[0049] The restoration circuit 223 performs the following restoration processes from the first to the fourth. In detail, the restoration circuit 223 is, Firstly, the video data whose gradation level has been smoothed by the smoothing circuit 221 is stored in the internal input memory. Secondly, focusing on one video pixel from the accumulated video data, and identifying the video pixels adjacent to that video pixel in a specific direction (for example, to the right), Thirdly, the amount of restoration corresponding to the grayscale data of the image pixel of interest and the grayscale data of the image pixels adjacent to that image pixel is read by referring to a two-dimensional table. Fourth, the read-out restored amount is added to the grayscale data of the image pixel of interest and stored in the internal output memory.

[0050] The restoration circuit 223 performs the first to fourth processes for the entirety of one frame by sequentially shifting the image pixels of interest in the video data stored in the internal input memory. After performing the processes for one frame of video data, the restoration circuit 223 similarly performs the first to fourth processes for the video data of the next frame.

[0051] Figure 12 shows an example of a two-dimensional table referenced by the restoration circuit 223. The two-dimensional table takes the grayscale level of the image pixel of interest and the grayscale levels of the image pixels adjacent to that pixel as input, and outputs the amount of restoration corresponding to those two grayscale levels. In the two-dimensional table, the grayscale level of the image pixel of interest is used as the horizontal axis, and the grayscale levels of the image pixels adjacent to that image pixel of interest are used as the vertical axis. Then, from the two-dimensional table, if the grayscale level of the image pixel of interest and the grayscale levels of the image pixels adjacent to that image pixel of interest are both above the threshold grayscale L_th1 and below the threshold grayscale Lth2, the restoration amount that cancels out the grayscale level smoothing by the smoothing circuit 221 is read out.

[0052] In the two-dimensional table, the region where the grayscale level of the image pixel of interest and the grayscale level of the image pixel adjacent to that image pixel of interest are both above threshold grayscale L_th1 and below threshold grayscale Lth2 is the region that is hatched in the figure. Furthermore, if the gradation level of the image pixel of interest, or at least one of the gradation levels of the image pixels adjacent to the image pixel of interest, is less than threshold gradation L_th1 or higher than threshold gradation Lth2, the amount of restoration read is zero. When a restoration amount of zero is added to the gradation data of the image pixel of interest, the gradation data does not change; that is, the smoothing effect of the smoothing circuit 221 is maintained. The video data, including the restoration amount which includes zeros, is stored in the internal output memory. The video data stored in the internal output memory is read out at a timing that matches the scanning of the LCD panel 100, converted into an analog data signal, and output.

[0053] Figures 13, 14, and 15 are diagrams illustrating the specific operation of the processing circuit 22 in the first embodiment. Of these diagrams, Figure 13 illustrates the smoothing and restoration of the gradation levels for adjacent black and white image pixels when displaying black text on a white background. Figure 14 illustrates the smoothing and restoration of gradation levels for adjacent black and white image pixels when displaying white text on a black background. Figure 15 illustrates the smoothing and restoration of gradation levels for adjacent relatively dark and relatively bright image pixels when displaying natural images.

[0054] In Figure 13, the video data for black image pixels is set to have a voltage applied to the liquid crystal element 120 of 0V before smoothing. Similarly, the video data for white image pixels is set to have a voltage applied to the liquid crystal element 120 of 5V before smoothing. When the gradation levels are smoothed by the smoothing circuit 221, the voltage applied to the liquid crystal element 120 corresponding to the black image pixel is corrected to be higher, for example, 2.0V, and the voltage applied to the liquid crystal element 120 corresponding to the white image pixel is corrected to be lower, for example, 4.6V.

[0055] Note that Figure 13 shows the case where black text is displayed on a white background, that is, when more black image pixels are placed around the black image pixels. Therefore, the amount of correction for the gradation level of the black image pixels is larger in absolute value than the amount of correction for the gradation level of the white image pixels when converted to the applied voltage. Furthermore, before smoothing, the gradation levels of black and white image pixels are outside the range of intermediate gradations even after smoothing, so the amount of restoration is zero. Therefore, even after the restoration process by the restoration circuit 223, the voltage applied to the liquid crystal element 120 corresponding to the black image pixel is 2.0V, and the voltage applied to the liquid crystal element 120 corresponding to the white image pixel is 4.6V, and neither changes after smoothing.

[0056] In Figure 14, before correction, the video data for black image pixels is set to apply a voltage of 0V to the liquid crystal element 120, and before correction, the video data for white image pixels is set to apply a voltage of 5V to the liquid crystal element 120. When the gradation levels are smoothed by the smoothing circuit 221, the voltage applied to the liquid crystal element 120 corresponding to the black image pixel is corrected to be higher, for example, 1.7V, and the voltage applied to the liquid crystal element 120 corresponding to the white image pixel is corrected to be lower, for example, 3.6V.

[0057] Note that Figure 14 shows the case where white text is displayed on a black background, that is, when more black image pixels are placed around the white image pixels. Therefore, the amount of correction for the gradation level of the black image pixels is smaller in absolute value than the amount of correction for the gradation level of the white image pixels when converted to the applied voltage. Furthermore, before smoothing, the gradation levels of black and white image pixels remain outside the range of intermediate gradations even after smoothing, so the amount of restoration is zero. Therefore, even after the restoration process by the restoration circuit 223, the voltage applied to the liquid crystal element 120 corresponding to the black image pixel is 1.2V, and the voltage applied to the liquid crystal element 120 corresponding to the white image pixel is 3.6V, and neither of these changes after smoothing.

[0058] In Figure 15, for the darker of two adjacent intermediate-tone image pixels, the voltage applied to the liquid crystal element 120 is set to, for example, 2.0V before smoothing. For the brighter of two adjacent intermediate-tone image pixels, the voltage applied to the liquid crystal element 120 is set to, for example, 3.0V before smoothing. When the gradation levels are smoothed by the smoothing circuit 221, the voltage applied to the liquid crystal element 120 corresponding to the darker image pixels in the intermediate gradation is corrected to be higher, for example, 2.2V, while the voltage applied to the liquid crystal element 120 corresponding to the brighter image pixels in the intermediate gradation is corrected to be lower, for example, 2.8V.

[0059] Even after smoothing, the gradation levels of the darker image pixels and the brighter image pixels remain within the range of intermediate gradations. Therefore, the smoothing of the gradation levels by the smoothing circuit 221 is offset by the restoration circuit 223, returning the gradation levels to their pre-smoothing state. The voltage applied to the liquid crystal element 120 corresponding to the darker image pixel in the intermediate grayscale range is returned to its original 2.0V, and the voltage applied to the liquid crystal element 120 corresponding to the brighter image pixel in the intermediate grayscale range is returned to its original 3.0V.

[0060] According to this first embodiment, when dark and bright image pixels, where discrinosis is expected to occur, are adjacent, smoothing that takes into account the surrounding image pixels with respect to the image pixel of interest is maintained, thereby suppressing a decrease in display quality due to discrinosis. Furthermore, when adjacent pixels are in intermediate tones, the smoothing by the smoothing circuit 221 is canceled out by the restoration circuit 223, preventing a conflict in display quality and thus suppressing blurring of the display.

[0061] The processing content of processing circuits 22R, 22G, and 22B in the first embodiment can be conceptualized as a display control method. Note that, as described above, the processing content itself is identical in processing circuits 22R, 22G, and 22B, except for the color components of the video data being processed. Therefore, the display control methods in processing circuits 22R, 22G, and 22B will be described as display control methods in processing circuit 22 without specifying the color components.

[0062] Figure 16 is a flowchart showing the display control method. First, in the processing circuit 22, the smoothing circuit 221 smooths the gradation level of the pixels specified by the video pixels accumulated for one frame (step S10).

[0063] Next, in the processing circuit 22, the restoration circuit 223 focuses on a single image pixel from the image data smoothed by the smoothing circuit 221 (step S11). Then, the restoration circuit 223 identifies the image pixels adjacent to the image pixel of interest in a specific direction (step S12). The restoration circuit 223 reads out the restoration amount corresponding to the grayscale level of the image pixel of interest and the grayscale level of the identified image pixel by referring to a two-dimensional table (step S13), and adds the read restoration amount to the grayscale level of the image pixel of interest (step S14).

[0064] If the grayscale levels of both video pixels are greater than or equal to threshold grayscale L_th1 and less than or equal to threshold grayscale L_th2, the recovered amount read out is a value that cancels out the smoothing by the smoothing circuit 221 and returns the grayscale level of the video pixel of interest to the smoothed grayscale level. On the other hand, if at least one of the two image pixels has a gradation level less than threshold gradation L_th1 or higher than threshold gradation L_th2, the amount of restoration read out is zero, and the gradation level of the image pixel of interest is maintained in a smoothed state by the smoothing circuit 221.

[0065] The restoration circuit 223 determines whether it has focused on all the video pixels in one frame (step S15). If the result of this determination is "No", the restoration circuit 223 shifts the video pixel being focused on to another video pixel (step S16) and returns to step S12. Therefore, steps S12 to S16 are repeatedly executed until all the video pixels in one frame have been focused on. If the result of step S15 is "Yes", it means that all the video pixels for one frame have been examined, so the processing circuit 22 moves the processing of the video pixels to the next frame (step S17) and returns the processing procedure to step S10.

[0066] These steps S11 to S17 are repeatedly executed as long as video data Vid_in is supplied from the host device (until the power is turned off).

[0067] In the first embodiment, when displaying black text on a white background, a stronger correction is applied to dark image pixels than to bright image pixels during gradation level smoothing. Specifically, looking at the voltage applied to the liquid crystal element 120, as shown in Figure 13, the applied voltage corresponding to image pixels with a gradation level of white is corrected from 5.0V to 4.6V, resulting in a correction of 0.4V, while the applied voltage corresponding to image pixels with a gradation level of black is corrected from 0V to 2.0V, resulting in a stronger correction of 2.0V than to black image pixels. Conversely, in the first embodiment, when displaying black text on a white background, the correction for bright image pixels is weak, and the discrimination becomes more easily visible in the panel pixels that represent those bright image pixels.

[0068] Therefore, a second embodiment that suppresses such discrinosis will be described. The projection-type display device 1 according to the second embodiment differs from the first embodiment only in the configuration of the processing circuits 22R, 22G, and 22B. Therefore, the processing circuits 22R, 22G, and 22B, which are the differences from the first embodiment, will be described for the second embodiment.

[0069] Figure 17 is a block diagram showing the configurations of processing circuits 22R, 22G, and 22B in the second embodiment. In the second embodiment, a correction circuit 225R is provided after the restoration circuit 223R in processing circuit 22R. Similarly, a correction circuit 225G is provided after the restoration circuit 223G in processing circuit 22G, and a correction circuit 225B is provided after the restoration circuit 223B in processing circuit 22B. Correction circuits 225R, 225G, and 225B differ only in the color component being processed; the processing content is the same. Therefore, when describing correction circuits 225R, 225G, and 225B without specifying the color component, the code of the correction circuit will be referred to as 225.

[0070] The correction circuit 225 adds the restoration amount to the smoothed gradation level and focuses on a single video pixel from the video data for one frame stored in the internal output memory of the restoration circuit 223. The correction circuit 225 then reduces the tone level of the image pixel of interest by a predetermined amount if a threshold tone is located between the tone level of the image pixel of interest and the tone level of an adjacent image pixel in a specific direction (for example, to the right) relative to the image pixel of interest. The predetermined amount may be, for example, a fixed amount determined in advance, or it may be an amount set to increase as the tone level of the image pixel of interest is higher than the threshold tone. Furthermore, although this threshold level is not specifically illustrated, we will refer to it as L_th3 for convenience.

[0071] On the other hand, the correction circuit 225 does not perform any processing on the gradation level of the image pixel of interest unless a threshold gradation L_th3 is located between the gradation level of the image pixel of interest and the gradation level of the image pixel adjacent to the image pixel of interest.

[0072] Furthermore, the threshold gradation L_th3 in the correction circuit 225, when converted using the voltage applied to the liquid crystal element 120, becomes a threshold voltage V_th3 that satisfies the following first and second conditions. In detail, the first condition is that the threshold voltage V_th3 is lower than the voltage obtained by correcting the voltage applied to the liquid crystal element 120 corresponding to the white image pixel through gradation level smoothing when white and black image pixels are adjacent in the display of black text on a white background. The second condition is that the threshold voltage V_th3 is higher than the voltage obtained by correcting the voltage applied to the liquid crystal element 120 corresponding to the white image pixel through gradation level smoothing when white and black image pixels are adjacent in the display of white text on a black background. Referring to the display examples in Figures 13 and 14, the threshold voltage V_th3 in the correction circuit 225 is less than 4.6V and higher than 3.6V. The correction circuit 225 reduces the gradation level of a bright image pixel by a predetermined amount if the threshold voltage V_th3 is located between the applied voltage corresponding to a dark image pixel and the applied voltage corresponding to a bright image pixel. Note that this is just one example of a threshold voltage V_th3; in reality, it should be set to a voltage at which the visible discrinations are not very noticeable.

[0073] The correction circuit 225 stores video data with reduced gradation levels, or video data that has not been processed, in the internal output memory. The video data stored in the internal output memory is read out at a timing synchronized with the scanning of the liquid crystal panel 100, converted into an analog data signal, and output.

[0074] Figures 18, 19, and 20 are diagrams illustrating the specific operation of the processing circuit 22 in the second embodiment. In these figures, Figure 18 shows the case where black text is displayed on a white background, similar to Figure 13; Figure 19 shows the case where white text is displayed on a black background, similar to Figure 14; and Figure 20 shows the case where a natural image is displayed, similar to Figure 15.

[0075] In Figure 18, when displaying black text on a white background, the voltage applied to the liquid crystal element 120 before smoothing, the voltage applied to the liquid crystal element 120 after smoothing, and the voltage applied to the liquid crystal element 120 after restoration processing are the same as in Figure 13 for black and white image pixels. Here, when displaying black text on a white background, the voltage applied to the liquid crystal element 120 after restoration processing is 2.0V for black image pixels. For white image pixels, the voltage applied to the liquid crystal element 120 after restoration processing is 4.6V. Since the threshold voltage V_th3 is located between 2.0V and 4.6V, the gradation level of white image pixels decreases during smoothing, remains unchanged during restoration processing, but decreases due to correction by the correction circuit 225.

[0076] Figure 18 shows an example where, when displaying black text on a white background, the voltage applied to the liquid crystal element 120 for white image pixels decreased from 4.6V after restoration processing to 4.1V. In the correction circuit 225, the darker image pixels, in this case the black image pixels, are not subject to correction. Therefore, the voltage applied to the liquid crystal element 120 at the black image pixels does not change from 2.0V after the restoration process due to the correction.

[0077] In Figure 19, when displaying white text on a black background, the voltage applied to the liquid crystal element 120 before smoothing, the voltage applied to the liquid crystal element 120 after smoothing, and the voltage applied to the liquid crystal element 120 after restoration processing are the same as in Figure 14 for black and white image pixels. Here, when displaying white text on a black background, the voltage applied to the liquid crystal element 120 after restoration processing is 1.2V for black image pixels. For white image pixels, the voltage applied to the liquid crystal element 120 after restoration processing is 3.6V. Since the threshold voltage V_th3 is not between 1.2V and 3.6V, the gradation level of white image pixels is not corrected by the correction circuit 225. Therefore, when displaying white text on a black background, the voltage applied to the liquid crystal element 120 for white image pixels does not change from 3.6V after the restoration process.

[0078] In Figure 20, when displaying a natural image, the voltage applied to the liquid crystal element 120 before smoothing, the voltage applied to the liquid crystal element 120 after smoothing, and the voltage applied to the liquid crystal element 120 after restoration processing are the same as in Figure 15 for bright and dark image pixels. Here, when displaying natural images, the voltage applied to the liquid crystal element 120 after restoration processing is 2.0V for dark image data. For bright image data, the voltage applied to the liquid crystal element 120 after restoration processing is 3.0V. Since the threshold voltage V_th3 is not located between 2.0V and 3.0V, the gradation level of bright video data is not corrected by the correction circuit 225. Therefore, when displaying natural images, the voltage applied to the liquid crystal element 120 for bright video data does not change from 3.0V after the restoration process.

[0079] According to this second embodiment, similar to the first embodiment, when dark and bright image pixels are adjacent, smoothing that takes into account the surrounding image pixels with respect to the image pixel of interest is maintained, thereby suppressing a decrease in display quality due to discrimination. Furthermore, when adjacent pixels are in intermediate tones, the smoothing by the smoothing circuit 221 is canceled out by the restoration circuit 223, preventing display conflicts and thus suppressing display blurring. Furthermore, in the second embodiment, in displays where bright image pixels serve as the background for dark image pixels, the bright image pixels adjacent to the dark image pixels are smoothed and then corrected, thereby reducing discrimination compared to the first embodiment.

[0080] The processing content of the processing circuits 22R, 22G, and 22B in the second embodiment can be conceptualized as a display control method, similar to the first embodiment.

[0081] Figure 21 is a flowchart of the display control method. In Figure 21, after the restoration process for one frame is performed compared to Figure 16, a correction process in the correction circuit 225 is added. This added correction process will be explained below.

[0082] In the processing circuit 22, the correction circuit 225 focuses on a single video pixel from the video data for one frame, to which the restoration amount (including zero) has been added by the restoration circuit 223 (step S21). Then, the correction circuit 225 identifies video pixels adjacent to the focused video pixel in a specific direction (step S22). The correction circuit 225 determines whether a threshold tone L_th3 is located between the tone level of the image pixel of interest and the tone level of the identified image pixel (step S23). If the judgment result is "Yes", the correction circuit 225 reduces the gradation level of the image pixel of interest by a predetermined amount (step S24). On the other hand, if the judgment result is "No", the correction circuit 225 skips the processing procedure to step S25 without performing any processing on the gradation level of the image pixel of interest.

[0083] After step S24, or if the result of the determination in step S23 is "No", the correction circuit 225 determines whether all video pixels for one frame have been examined (step S25). If this determination result is "No", the correction circuit 225 shifts the video pixel under examination to another video pixel (step S26) and returns to the processing procedure in step S22. Therefore, in the correction circuit 225, steps S21 to S26 are repeatedly executed until all video pixels for one frame are considered. If the result of step S25 is "Yes", it means that all the video pixels for one frame have been examined, so the processing circuit 22 moves the video pixel processing procedure to the next frame (step S27) and returns the processing procedure to step S10.

[0084] These steps S10-S17 and S21-27 are executed repeatedly as long as video data Vid_in is supplied from the host device (until the power is turned off).

[0085] Furthermore, liquid crystal displays can be applied to electronic devices other than projection-type display devices 1. For example, they can be applied to head-mounted displays, electronic viewfinders in video cameras or interchangeable-lens digital cameras, personal digital assistants, and watch displays.

[0086] From the forms exemplified above, the following aspects can be understood, for example.

[0087] A liquid crystal display device according to one embodiment 1 includes a liquid crystal panel having panel pixels and a display control circuit for controlling the liquid crystal panel, wherein the gradation level of the image pixels constituting the image data is specified by pixel data, and the image pixels include a first image pixel and a first adjacent image pixel adjacent to the first image pixel, and the display control circuit supplies a voltage data signal to the panel pixel corresponding to the first image pixel based on the gradation level specified by the pixel data of the first image pixel, and supplies a voltage data signal to the panel pixel corresponding to the first adjacent image pixel based on the gradation level specified by the pixel data of the first adjacent image pixel A data signal with a voltage based on a bell is supplied, and the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel is made different from the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel when both the gradation level specified by the pixel data of the first video pixel and the gradation level specified by the pixel data of the first adjacent video pixel are within the range of intermediate gradations, which is between a first threshold gradation and a second threshold gradation.

[0088] According to the liquid crystal display device of Embodiment 1, it becomes possible to suppress blurring of the display that occurs in intermediate grayscale levels. Furthermore, when focusing on a particular image pixel, that image pixel is an example of a "first image pixel," and the image pixel adjacent to that image pixel to the right is an example of a "first adjacent image pixel." Threshold level Lth_1 is an example of a "first threshold level," and threshold level Lth_2 is an example of a "second threshold level." Furthermore, "adjacent" simply means being next to each other, and includes cases where they are not adjacent.

[0089] In a liquid crystal display device according to a specific embodiment 2 of embodiment 1, the image pixels include a second adjacent image pixel that is adjacent to the first image pixel and is an image pixel other than the first adjacent image pixel, and the display control circuit smooths the gradation level specified by the pixel data of the first image pixel based on the gradation level specified by the pixel data of the first adjacent image pixel and the gradation level specified by the pixel data of the second adjacent image pixel, and then determines whether the gradation level specified by the pixel data of the first image pixel and the gradation level specified by the pixel data of the first adjacent image pixel are within or outside the range of the intermediate gradation. According to the liquid crystal display device of embodiment 2, it is possible to suppress the deterioration of display quality due to discrimination and suppress the blurring of the display that occurs in intermediate grayscale levels. For reference, an example of a "second adjacent image pixel" is an image pixel that is adjacent to the image pixel of interest to the left, right, above, or below.

[0090] In a liquid crystal display device according to a specific embodiment 3 of embodiment 2, the display control circuit lowers the smoothed gradation level for the first image pixel if the smoothed gradation level for the first image pixel is higher than the smoothed gradation level for the first adjacent image pixel, and at least one of the smoothed gradation level for the first image pixel or the smoothed gradation level for the first adjacent image pixel is outside the range of intermediate gradation. According to the liquid crystal display device of embodiment 3, it is possible to suppress discriminations that are easily visible in response to bright image pixels.

[0091] Another embodiment 4 of the liquid crystal display device includes a liquid crystal panel having panel pixels and a display control circuit for controlling the liquid crystal panel, wherein the image pixels constituting the image data are arranged in a first direction and a second direction, the gradation level of the image pixels is specified by the pixel data, and the display control circuit applies a first correction to the pixel data of one image pixel based on the pixel data of two or more adjacent image pixels in the first direction, the direction opposite to the first direction, the second direction, or the direction opposite to the second direction, and among the pixel data after the first correction, the image of interest is selected. The system determines whether both the voltage corresponding to the grayscale level of the pixel data of a pixel and the voltage corresponding to the grayscale level of the pixel data of an adjacent video pixel in either the first or second direction to the video pixel of interest are in an intermediate grayscale between a first threshold voltage and a second threshold voltage. If both voltages are within the intermediate grayscale range, a second correction is applied to cancel out the first correction applied to the pixel data of the video pixel of interest, and a data signal based on the pixel data after the first correction, or, if the second correction has been applied, the pixel data after the second correction, is supplied to the panel pixel.

[0092] According to the liquid crystal display device of embodiment 4, it is possible to suppress the deterioration of display quality due to discrimination and suppress the blurring of the display that occurs in intermediate grayscales. Note that the right direction is an example of the "first direction," the left direction is an example of the "opposite direction of the first direction," the downward direction is an example of the "second direction," and the upward direction is an example of the "opposite direction of the second direction." Voltage V_th1 is an example of a "first threshold voltage," and voltage V_th2 is an example of a "second threshold voltage." Smoothing is an example of a "first correction," and restoration is an example of a "second correction."

[0093] The control method for a liquid crystal display device according to Embodiment 5 includes a liquid crystal panel having panel pixels and a display control circuit for controlling the liquid crystal panel, wherein the gradation level of the image pixels constituting the image data is specified by pixel data, and the image pixels include a first image pixel and a first adjacent image pixel adjacent to the first image pixel, and a voltage data signal based on the gradation level specified by the pixel data of the first image pixel is supplied to the panel pixel corresponding to the first image pixel, and a control method based on the gradation level specified by the pixel data of the first adjacent image pixel is supplied to the panel pixel corresponding to the first adjacent image pixel. A data signal of a certain voltage is supplied, and when both the gradation level specified by the pixel data of the first video pixel and the gradation level specified by the pixel data of the first adjacent video pixel are within the range of intermediate gradations, which is between a first threshold gradation and a second threshold gradation, the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel is made different from the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel when at least one of the gradation level of the first video pixel or the gradation level of the first adjacent video pixel is outside the range of intermediate gradations. According to the control method for the liquid crystal display device in embodiment 5, it becomes possible to suppress blurring of the display that occurs in intermediate grayscale levels.

[0094] The electronic device according to embodiment 6 includes a liquid crystal display device according to any one of embodiments 1 to 4. [Explanation of Symbols]

[0095] 1...Projection type display device, 100R, 100G, 100B...Liquid crystal panel, 110...Pixel circuit, 118...Pixel electrode, 120...Liquid crystal element, 20...Display control circuit, 22R, 22G, 22B...Processing circuit, 221, 221R, 221G, 221B...Smoothing circuit, 223, 223R, 223G, 221B...Restoration circuit, 225, 225R, 225G, 221B...Correction circuit.

Claims

1. A liquid crystal panel having panel pixels, A display control circuit for controlling the liquid crystal panel, Includes, The gradation level of the image pixels that make up the video data is specified in the pixel data. The aforementioned image pixels are The first image pixel and, The first adjacent image pixel adjacent to the first image pixel, Includes, The aforementioned display control circuit is A voltage data signal based on the grayscale level specified by the pixel data of the first video pixel is supplied to the panel pixel corresponding to the first video pixel. A voltage data signal based on the grayscale level specified by the pixel data of the first adjacent video pixel is supplied to the panel pixel corresponding to the first adjacent video pixel. When both the gradation level specified by the pixel data of the first video pixel and the gradation level specified by the pixel data of the first adjacent video pixel are within the range of intermediate gradations, which is between a first threshold gradation and a second threshold gradation, the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel is set to If at least one of the gradation levels of the first video pixel or the gradation levels of the first adjacent video pixel is outside the range of intermediate gradation, the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel is made different. LCD display device.

2. The aforementioned image pixels are Includes a second adjacent image pixel that is adjacent to the first adjacent image pixel, other than the first adjacent image pixel, The aforementioned display control circuit is After smoothing the gradation level specified by the pixel data of the first video pixel based on the gradation level specified by the pixel data of the first adjacent video pixel and the gradation level specified by the pixel data of the second adjacent video pixel, Determine whether the gradation level specified by the pixel data of the first video pixel and the gradation level specified by the pixel data of the first adjacent video pixel are within or outside the range of the intermediate gradation. The liquid crystal display device according to claim 1.

3. The aforementioned display control circuit is The smoothed gradation level for the first image pixel is higher than the smoothed gradation level for the first adjacent image pixel. If at least one of the smoothed gradation level for the first image pixel, or the smoothed gradation level for the first adjacent image pixel, is outside the range of the intermediate gradation, The smoothed gradation level of the first image pixel is reduced. The liquid crystal display device according to claim 2.

4. A liquid crystal panel having panel pixels, A display control circuit for controlling the liquid crystal panel, Includes, The video pixels that make up the video data are arranged in a first direction and a second direction. The grayscale level of the aforementioned video pixels is specified by the pixel data. The aforementioned display control circuit is With respect to the pixel data of one video pixel, a first correction is applied to that video pixel based on the pixel data of two or more adjacent video pixels in the first direction, the direction opposite to the first direction, the second direction, or the direction opposite to the second direction. From the pixel data after the first correction, it is determined whether the voltage corresponding to the grayscale level of the pixel data of the image pixel of interest and the voltage corresponding to the grayscale level of the pixel data of the image pixel adjacent to the image pixel of interest in either the first or second direction are both intermediate grayscale levels between the first threshold voltage and the second threshold voltage. When both of the aforementioned voltages are within the range of the intermediate grayscale, A second correction is applied to the pixel data of the image pixel of interest to cancel out the first correction applied to it. The first corrected pixel data, or, if a second correction has been applied, the second corrected pixel data, is used to supply a data signal to the panel pixels. LCD display device.

5. A liquid crystal panel having panel pixels, A display control circuit for controlling the liquid crystal panel, Includes, The gradation level of the image pixels that make up the video data is specified in the pixel data. The aforementioned image pixels are The first image pixel and, The first adjacent image pixel adjacent to the first image pixel, Includes, A voltage data signal based on the grayscale level specified by the pixel data of the first video pixel is supplied to the panel pixel corresponding to the first video pixel. A voltage data signal based on the grayscale level specified by the pixel data of the first adjacent video pixel is supplied to the panel pixel corresponding to the first adjacent video pixel. When both the gradation level specified by the pixel data of the first video pixel and the gradation level specified by the pixel data of the first adjacent video pixel are within the range of intermediate gradations, which is between a first threshold gradation and a second threshold gradation, the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel is set to If at least one of the gradation levels of the first video pixel or the gradation levels of the first adjacent video pixel is outside the range of intermediate gradation, the voltage of the data signal supplied to the panel pixel corresponding to the first video pixel is made different. A method for controlling a liquid crystal display device.

6. An electronic device having a liquid crystal display device according to any one of claims 1 to 4.

Images