Projection display device

Abstract

Projection display device. Suppressing display defects when using an optical path shift element (230). The projection display device (1) supplies a data signal based on image pixel data (A1) corresponding to the unit period (f1-f4) constituting one frame to a panel pixel (a1), and supplies a data signal based on image pixel data (C1) corresponding to the unit period to a panel pixel (b1) adjacent to the panel pixel (a1), and corrects the first grayscale level and the second grayscale level in a manner that reduces the difference between the first grayscale level of the image pixel data (A1) and the second grayscale level of the image pixel data (C1), so that the grayscale levels of three consecutive image pixel data in the direction in which the image pixel data (C1) is located relative to the image pixel data (A1) are consistent with the grayscale level of the corrected image pixel data (C1) and are the same value.

Description

Technical Field

[0001] The present invention relates to a projection type display device. Background Art

[0002] In recent years, as the miniaturization and high-definition of liquid crystal panels have developed, when the gap between pixel electrodes becomes narrower, the influence of the electric field generated by adjacent pixel electrodes, that is, the electric field in the direction parallel to the substrate surface (lateral electric field) cannot be ignored. Specifically, the poor orientation of liquid crystals, that is, domains, is generated due to the lateral electric field, which is observed as a poor display condition.

[0003] In order to suppress the display defects caused by domains, the following technology is proposed: when it is expected that the lateral electric field will become stronger, the image data supplied from the upper device is corrected so that the difference in voltage applied to adjacent pixel electrodes is reduced. In addition, such correction is called domain correction (for example, refer to the description of Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Publication No. 2011-170235 Summary of the invention

[0005] Problems to be solved by the invention

[0006] However, when the structure of shifting the projection position of one panel pixel of the liquid crystal panel 100 by the optical path shift element is applied to domain correction, the brightness of the panel pixel sometimes changes as in the case of a dynamic image display even when a static image is displayed. Therefore, there is a problem that the display quality sometimes decreases due to the domain.

[0007] Means for solving problems

[0008] In order to solve the above-mentioned problems, a projection display device of one embodiment of the present invention includes: a liquid crystal panel, which has a plurality of panel pixels, a first panel pixel of the plurality of panel pixels is adjacent to a second panel pixel; an optical path shifting element, which shifts the optical path of the projection light projected from the panel pixel to shift the position of the projection pixel; and a display control circuit, which controls the liquid crystal panel and the optical path shifting element, wherein, among the image pixel data constituting the image data input to the liquid crystal panel and arranged in a matrix, k (k is an integer greater than 2) image pixel data individually correspond to the first panel pixels within the k unit periods, and k image pixel data individually correspond to the second panel pixels within the k unit periods, and the k image pixel data corresponding to the first panel pixels are different from the k image pixel data corresponding to the second panel pixels, and the display control circuit performs the following control: with respect to the optical path A shift element controls the shift of the position of the projection pixel in each of the k unit periods, and in one unit period among the k unit periods, supplies a data signal based on the image pixel data corresponding to the one unit period to the first panel pixel, and supplies a data signal based on the image pixel data corresponding to the one unit period to the second panel pixel, and in the k image pixel data corresponding to the first panel pixel, at least corrects the second grayscale level in a manner that reduces the difference between the first grayscale level of the first image pixel data corresponding to the one unit period and the second grayscale level of the second image pixel data corresponding to the one unit period, so that the grayscale levels of (k-1) image pixel data that are continuous in the direction in which the second image pixel is located relative to the first image pixel and that include the second image pixel data are consistent with the corrected second grayscale level and are the same value. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a diagram showing a projection type display device according to an embodiment.

[0010] Figure 2 It is a block diagram showing the structure of a projection type display device.

[0011] Figure 3 This is a diagram showing one frame and a unit period in a projection type display device.

[0012] Figure 4 This is a diagram showing the relationship between image pixels and panel pixels in a projection display device.

[0013] Figure 5 This is a diagram showing the relationship between image pixels, panel pixels, and projection positions in one frame.

[0014] Figure 6It is a perspective view showing the structure of a liquid crystal panel in a projection type display device.

[0015] Figure 7 is a cross-sectional view showing the structure of a liquid crystal panel.

[0016] Figure 8 is a block diagram showing the electrical structure of a liquid crystal panel.

[0017] Fig. 9 A diagram showing the structure of a pixel circuit in a liquid crystal panel.

[0018] Fig.10 This is a diagram showing an example of VT characteristics in a liquid crystal element.

[0019] Fig.11 A diagram for explaining domains in a liquid crystal panel.

[0020] Fig.12 It is a diagram showing conventional domain correction and the like.

[0021] Fig.13 It is a diagram for explaining the first correction.

[0022] Fig.14 It is a diagram for explaining the second correction.

[0023] Fig.15 It is a diagram for explaining the third correction.

[0024] Fig.16 It is a diagram showing an example of a processing circuit in the embodiment.

[0025] Fig.17 It is a diagram showing another example of the processing circuit in the embodiment.

[0026] Fig.18 It is a diagram showing an example of a coefficient matrix of a filter processing circuit in the processing circuit.

[0027] Description of symbols

[0028] 1: projection display device; 100R, 100G, 100B: liquid crystal panel; 110: pixel circuit; 118: pixel electrode; 120: liquid crystal element; 20: display control circuit; 22: processing circuit; 220: filtering processing circuit; 221: gamma correction circuit; 222: domain correction circuit; 225: separation circuit; 226: overdrive correction circuit; 230: optical path shift element. DETAILED DESCRIPTION

[0029] Hereinafter, the projection display device of the embodiment will be described with reference to the accompanying drawings. In addition, in each figure, the size and scale of each part are appropriately different from the actual size and scale. In addition, the embodiment described below is a preferred specific example, and therefore various technically preferred limitations are added, but as long as there is no record of the subject matter of the present disclosure being particularly limited in the following description, the scope of the present disclosure is not limited to these modes.

[0030] Figure 1 1 is a diagram showing the optical structure of the projection display device 1 according to the first embodiment. Figure 1 As shown, the projection display device 1 includes liquid crystal panels 100R, 100G, and 100B. In addition, a lamp unit 2102 composed of a white light source such as a halogen lamp is provided inside the projection display device 1. The projection light emitted from the lamp unit 2102 is separated into three primary colors of red (R), green (G), and blue (B) by three reflectors 2106 and two dichroic mirrors 2108 arranged inside. Among them, R light is incident on the liquid crystal panel 100R, G light is incident on the liquid crystal panel 100G, and B light is incident on the liquid crystal panel 100B.

[0031] In addition, since the optical path of B is longer than the optical paths of R and G, it is necessary to prevent loss in the optical path of B. Therefore, a relay lens system 2121 composed of an incident lens 2122, a relay lens 2123, and an exit lens 2124 is provided on the optical path of B.

[0032] The liquid crystal panel 100R has a pixel circuit arranged in a matrix as described later. In the above-mentioned pixel circuit, the transmittance of the light emitted from the liquid crystal element is controlled based on the data signal corresponding to R. That is, in the liquid crystal panel 100R, the emitted light from the liquid crystal element functions as the minimum unit of the image. Through 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.

[0033] The transmitted images of the respective colors 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 light of R and B is refracted 90 degrees, while the light of G goes straight. Therefore, the dichroic prism 2112 synthesizes the images of the respective colors. The synthesized light of the dichroic prism 2112 is incident on the projection lens 2114 via the optical path shifting element 230. The optical path shifting element 230 shifts the optical path emitted from the dichroic prism 2112. In detail, the optical path shifting element 230 can shift the image projected on the screen Scr in the left-right direction and the up-down direction relative to the projection surface.

[0034] The projection lens 2114 enlarges and projects the synthesized image passed through the optical path shift element 230 onto the screen Scr.

[0035] For the sake of convenience, in order to distinguish between pixels projected onto the screen Scr and pixels synthesized by the liquid crystal panels 100R, 100G, and 100B, the pixels projected onto the screen Scr are marked as projected pixels, and the pixels before or after synthesis of the liquid crystal panels 100R, 100G, or 100B are marked as panel pixels. In addition, the position of the projected pixel via the optical path shifting element 230 is simply marked as a projection position.

[0036] The transmitted images of the liquid crystal panels 100R and 100B are projected after being reflected by the dichroic prism 2112, whereas the transmitted image of the liquid crystal panel 100G is projected straight. Therefore, the transmitted images of the liquid crystal panels 100R and 100B are inverted left-right relation with respect to the transmitted image of the liquid crystal panel 100G.

[0037] Figure 2 1 is a block diagram showing the electrical structure of the projection type display device 1. Figure 2 As shown, the projection type display device 1 includes a display control circuit 20 , the above-mentioned liquid crystal panels 100R, 100G and 100B, and an optical path shifting element 230 .

[0038] The video data Vid_in is supplied to the display control circuit 20 from a host device (not shown) in synchronization with a synchronization signal Sync. The video data Vid_in is data representing an image to be displayed by the projection display device 1, and specifically specifies the grayscale level in pixels of the image using 8 bits for RGB, for example.

[0039] In addition, pixels of an image specified by the image data Vid_in are denoted as image pixels, and data specifying the grayscale level of the image pixels are denoted as image pixel data, but the image pixels and image pixel data may be described without particularly distinguishing between them.

[0040] The synchronization signal Sync includes a vertical synchronization signal for instructing the start of vertical scanning of the video data Vid_in, a horizontal synchronization signal for instructing the start of horizontal scanning, and a clock signal indicating the timing of one pixel of the video data.

[0041] In this embodiment, the color image projected on the screen Scr is represented by overlapping the transmission images of the liquid crystal panels 100R, 100G, and 100B. Therefore, the pixel, which is the minimum unit of the color image, can be divided into the red panel pixel of the liquid crystal panel 100R, the green panel pixel of the liquid crystal panel 100G, and the blue panel pixel of the liquid crystal panel 100B.

[0042] It should be noted that, strictly speaking, the red panel pixel, the green panel pixel, and the blue panel pixel should be labeled as sub-pixels, but in this specification, they are labeled as panel pixels as described above.

[0043] The liquid crystal panels 100R, 100G, and 100B differ only in the color of incident light, that is, in wavelength, and have a common structure. Therefore, when a specific color is not necessary for explanation, the liquid crystal panels 100R, 100G, and 100B are denoted by 100.

[0044] The display control circuit 20 includes a control circuit 21 and processing circuits 22R, 22G, and 22B.

[0045] In this embodiment, the pixel arrangement of the image specified by the image data Vid_in is, for example, twice as large in the vertical direction and twice as large in the horizontal direction as the arrangement of the panel pixels in the liquid crystal panel 100. Therefore, in this embodiment, the projection direction is shifted by the optical path shifting element 230 in order to improve the resolution in a simulated manner.

[0046] Specifically, when displaying one frame of an image specified by the image data Vid_in, the period for displaying one frame is divided into four unit periods, and the projection position is shifted for each unit period. By such shifting, one panel pixel appears to be displaying four image pixels specified by the image data Vid_in.

[0047] Before describing the control circuit 21 and the processing circuits 22R, 22G, and 22B, a method for expressing four image pixels designated by the image data Vid_in by one panel pixel in the liquid crystal panel 100 will be described.

[0048] Figure 3 This is a diagram for explaining the relationship between frames and unit periods in this embodiment. As shown in this diagram, in this embodiment, one frame F is divided into four unit periods. In addition, in order to conveniently distinguish the four unit periods in frame F, they are given labels f1, f2, f3, and f4 in chronological order.

[0049] In addition, frame F is a period of one frame of an image represented by video data Vid_in supplied from a host device, and when the frequency of a vertical synchronization signal included in synchronization signal Sync is 60 Hz, one cycle is 16.7 milliseconds. In this case, the unit periods f1 to f4 are each 4.17 milliseconds long.

[0050] Next, the relationship between the image pixel of the grayscale level specified by the image data Vid_in, the panel pixel of the liquid crystal panel 100, and the projection position of the optical path shift element 230 is described. In addition, regarding the optical path shift element 230, the projection direction from the dichroic prism 2112 is shifted as described above, but for convenience, the shift amount is converted into the size of the projected pixel on the screen Scr for description.

[0051] Figure 4 The left column in FIG. 1 is a diagram showing only a portion of the arrangement of image pixels represented by the image data Vid_in. Figure 4 The right column in is a diagram showing the arrangement of the image pixels and the arrangement corresponding to the left column, extracted from the panel pixels.

[0052] exist Figure 4 In the arrangement of the middle left column, in order to distinguish the image pixels in the image represented by the image data Vid_in, as labels, A1 to A6 are assigned to the first row, B1 to B6 to the second row, C1 to C6 to the third row, D1 to D6 to the fourth row, E1 to E6 to the fifth row, and F1 to F6 to the sixth row are assigned. Similarly, in Figure 4 In the arrangement of the right column in , in order to distinguish the panel pixels, for convenience, as labels, a1~a3 are assigned to the first row, b1~b3 are assigned to the second row, and c1~c3 are assigned to the third row.

[0053] Figure 5 1 is a diagram showing which image pixel of an image represented by the image data Vid_in is displayed at which projection position by the panel pixel of the liquid crystal panel 100 in the projection display device 1. Specifically, Figure 5 It is shown Figure 4 At which projection position do the nine panel pixels of the liquid crystal panel 100 in the right column display in the unit period f1 to f4? Figure 4 Which image pixel in the arrangement of image pixels represented by the image data Vid_in in the left column of the figure.

[0054] For the sake of convenience, the projection position in the unit period f1 of the frame F is set as the reference position.

[0055] In the unit period f1, the panel pixels a1 to a3, b1 to b3, and c1 to c3 sequentially display the image pixels A1, A3, A5, C1, C3, C5, E1, E3, and E5 of the image data Vid_in.

[0056] In the next unit period f2, the optical path shifting element 230 shifts the projection position from the projection position in the unit period f1 indicated by the dotted line to the right in the figure by 0.5 pixels of the liquid crystal panel 100. In addition, in the unit period f2, the panel pixels a1 to a3, b1 to b3, c1 to c3 of the liquid crystal panel 100 sequentially display the image pixels A2, A4, A6, C2, C4, C6, E2, E4 and E6 of the image data Vid_in.

[0057] In the unit period f3, the optical path shifting element 230 shifts the projection position from the projection position in the unit period f2 indicated by the dotted line downward in the figure by 0.5 pixels of the liquid crystal panel 100. In addition, in the unit period f3, the panel pixels a1 to a3, b1 to b3, and c1 to c3 of the liquid crystal panel 100 sequentially display the image pixels B2, B4, B6, D2, D4, D6, F2, F4, and F6 of the image data Vid_in.

[0058] Then, in the unit period f4, the optical path shifting element 230 shifts the projection position from the projection position in the unit period f3 indicated by the dotted line to the left in the figure by 0.5 pixels of the liquid crystal panel 100. In addition, in the unit period f4, the panel pixels a1 to a3, b1 to b3, c1 to c3 of the liquid crystal panel 100 sequentially display the image pixels B1, B3, B5, D1, D3, D5, F1, F3 and F5 of the image data Vid_in.

[0059] After the unit period f4 , the optical path shift element 230 shifts the projection position from the projection position in the unit period f4 upward by 0.5 pixels of the liquid crystal panel 100 in the figure and returns to the position in the unit period f1 .

[0060] Return to Figure 2 To explain, the control circuit 21 generates a control signal Ctr for controlling scanning of the liquid crystal panels 100R, 100G, and 100B for each unit period. In addition, the control circuit 21 controls the projection position of the optical path shift element 230 for each unit period.

[0061] The processing circuits 22R, 22G, and 22B will be described in detail later. The processing circuit 22R processes the video data Va_R of the R component in the video data Vid_in in each unit period f1 to f4, converts it into an analog data signal Vid_R, and supplies it to the liquid crystal panel 100R.

[0062] Similarly, the image data Va_G of the G component in the image data Vid_in is processed in each unit period f1 to f4, converted into an analog data signal Vid_G and supplied to the liquid crystal panel 100G, and the image data Va_B of the B component in the image data Vid_in is processed in each unit period f1 to f4, converted into an analog data signal Vid_B and supplied to the liquid crystal panel 100B.

[0063] Next, the liquid crystal panels 100R, 100G, and 100B are described. The liquid crystal panels 100R, 100G, and 100B differ only in the color of incident light, that is, the wavelength, and have a common structure. Therefore, the liquid crystal panels 100R, 100G, and 100B are denoted by 100 and are generally described without specifying a color.

[0064] Figure 6 is a diagram showing a main part of the liquid crystal panel 100, Figure 7 So Figure 6 Cross-sectional view taken along line Hh in FIG.

[0065] As shown in these figures, in the liquid crystal panel 100, the element substrate 100a provided with the pixel electrode 118 and the counter substrate 100b provided with the common electrode 108 are bonded together by a sealing material 90 with the electrode forming surfaces facing each other with a certain gap maintained, and the liquid crystal 105 is sealed in the gap.

[0066] As the element substrate 100a and the counter substrate 100b, a light-transmitting substrate such as glass or quartz is used. Figure 6 As shown in FIG. 1 , one side of the element substrate 100a extends from the counter substrate 100b. Figure 6 A plurality of terminals 106 are provided in the horizontal direction. The plurality of terminals 106 are connected to one end of a FPC (Flexible Printed Circuits) substrate (not shown). The other end of the FPC substrate is connected to the display control circuit 20 and is supplied with the above-mentioned various signals.

[0067] The pixel electrode 118 is formed on the surface of the element substrate 100 a that faces the counter substrate 100 b by patterning a transparent conductive layer such as ITO (Indium Tin Oxide).

[0068] In addition, although not specifically shown in the figure, in order to efficiently send a large amount of light to the opening portion that becomes the panel pixel, a microlens is provided for each panel pixel on the opposing substrate 100b (or the element substrate 100a). With this structure, the light bounced by the light shielding portion is sent to the opening portion of the microlens, thereby improving the efficiency of light utilization.

[0069] Figure 8 2 is a block diagram showing an electrical structure of the liquid crystal panel 100 . In the liquid crystal panel 100 , a scanning line driving circuit 130 and a data line driving circuit 140 are provided around the display region 10 .

[0070] In the display area 10 of the liquid crystal panel 100, the pixel circuits 110 are arranged in a matrix. Specifically, in the display area 10, a plurality of scanning lines 12 are arranged to extend in the horizontal direction in the figure, and a plurality of data lines 14 are arranged to extend in the vertical direction and to be electrically insulated from the scanning lines 12. In addition, the pixel circuits 110 are arranged in a matrix corresponding to the intersections of the plurality of scanning lines 12 and the plurality of data lines 14.

[0071] When the number of scanning 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 in the vertical direction and n columns in the horizontal direction. Both m and n are integers greater than 2. In order to distinguish the rows of the matrix in the scanning lines 12 and the pixel circuits 110, they are sometimes referred to as 1, 2, 3, ..., (m-1), and m rows from the top in the figure. Similarly, in order to distinguish the columns of the matrix in the data lines 14 and the pixel circuits 110, they are sometimes referred to as 1, 2, 3, ..., (n-1), and n columns from the left in the figure.

[0072] The scanning line driving circuit 130 selects the scanning 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 scanning signal for the selected scanning line 12 to the H level. In addition, the scanning line driving circuit 130 sets the scanning signal for the scanning lines 12 other than the selected scanning line 12 to the L level.

[0073] The data line driving circuit 140 latches a row of data signals supplied from the circuit of the corresponding color in the processing circuit 22R, 22G or 22B, and outputs the data signals to the pixel circuit 110 located on the scanning line 12 via the data line 14 while the scanning signal for the scanning line 12 is at the H level.

[0074] Fig. 9 1 is a diagram showing an equivalent circuit of four pixel circuits 110 in two vertical rows and two horizontal columns corresponding to the intersection of two adjacent scanning lines 12 and two adjacent data lines 14 .

[0075] like Fig. 9 As shown, 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 scanning line 12, the source node of the transistor 116 is connected to the data line 14, and the drain node of the transistor 116 is connected to the pixel electrode 118 which is square in shape when viewed from above.

[0076] The common electrode 108 is provided in common to all pixels so as to face the pixel electrode 118. A voltage LCcom is applied to the common electrode 108. The liquid crystal 105 is sandwiched between the pixel electrode 118 and the common electrode 108 as described above. Therefore, a liquid crystal element 120 in which the liquid crystal 105 is sandwiched between the pixel electrode 118 and the common electrode 108 is formed for each pixel circuit 110.

[0077] In addition, 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 capacitor line 107. A temporally constant voltage is applied to the capacitor line 107, for example, a voltage LCcom that is the same as the voltage applied to the common electrode 108. The pixel circuit 110 is arranged in a matrix in the horizontal direction, which is the extension direction of the scanning line 12, and in the vertical direction, which is the extension direction of the data line 14, so the pixel electrodes 118 included in the pixel circuit 110 are also arranged in the vertical and horizontal directions.

[0078] In the scanning line 12 whose scanning signal becomes H level, the transistor 116 of the pixel circuit 110 provided corresponding to the scanning line 12 becomes on. By the on-state of the transistor 116, 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-state transistor 116. When the scanning line 12 becomes L level, the transistor 116 becomes off, but the voltage of the data signal reaching the pixel electrode 118 is held by the capacitive property of the liquid crystal element 120 and the storage capacitor 109.

[0079] As is well known, in the liquid crystal element 120, the orientation of the liquid crystal molecules changes according to the electric field generated by the pixel electrode 118 and the common electrode 108. Therefore, the liquid crystal element 120 has a transmittance corresponding to the effective value of the applied voltage.

[0080] In addition, the area in the liquid crystal element 120 that functions as a panel pixel, that is, the area with a transmittance corresponding to the effective value of the voltage, is the area where the pixel electrode 118 overlaps with the common electrode 108 when the element substrate 100a and the counter substrate 100b are viewed from above. The pixel electrode 118 is square in plan view, and therefore, the shape of the pixel of the liquid crystal panel 100 is also square.

[0081] In this embodiment, the liquid crystal 105 is of VA (Vertical Alignment) type, which is a normally black mode in which 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.

[0082] The operation of supplying the data signal to the pixel electrode 118 of the liquid crystal element 120 is performed in the order of the 1st, 2nd, 3rd, ..., mth row in each unit period f1 to f4. Thus, the liquid crystal elements 120 of the pixel circuit 110 arranged in m rows and n columns respectively maintain a voltage corresponding to the data signal, and each liquid crystal element 120 becomes a target transmittance, and a transmission image of a corresponding color is generated by the liquid crystal elements 120 arranged in m rows and n columns.

[0083] In this way, the transmission image is generated for each RGB, and a color image synthesized from RGB is projected onto the screen Scr.

[0084] The data signals Vid_R, Vid_G, and Vid_B outputted corresponding to a certain unit period correspond to the RGB components of the video data corresponding to the unit period. Therefore, a color composite image corresponding to the projection position is projected at the projection position during the unit period.

[0085] Here, domains in the liquid crystal panel 100 will be described.

[0086] Fig.10 1 is a diagram showing an example of applied voltage-transmittance characteristics (VT characteristics) of the liquid crystal element 120 in the normally black mode.

[0087] In the normally black mode, in the panel pixels (bright panel pixels) where the transmittance increases due to the high grayscale level specified, the voltage applied to the liquid crystal element 120 is high. On the other hand, in the panel pixels (dark panel pixels) where the transmittance decreases due to the low grayscale level specified, the voltage applied to the liquid crystal element 120 is low.

[0088] Such bright panel pixels and dark panel pixels are defined as follows for convenience.

[0089] A bright panel pixel is a pixel in which a voltage higher than VH is applied to a liquid crystal element 120 including the pixel electrode 118 when a voltage corresponding to the grayscale level is applied to the pixel electrode 118, and a dark panel pixel is a pixel in which a voltage lower than VL is applied to the liquid crystal element 120. Among them, VH and VL are in a relationship of VH>VL. In addition, when the applied voltage of the liquid crystal element 120 is the voltage VL, for example, the relative transmittance is 10%, and when the voltage VH is the voltage, for example, the relative transmittance is 90%. However, VL and VH may also be voltages corresponding to other relative transmittances.

[0090] like Fig.11As shown, in the liquid crystal panel 100, when the bright panel pixel Lp is adjacent to the dark panel pixel Dp, the voltage difference between the pixel electrodes 118 becomes larger, and due to the lateral electric field generated in the direction along the substrate surface, the phenomenon of disordered orientation of liquid crystal molecules, i.e., domains, is easily generated near the boundary Edg between the two panel pixels. Generally speaking, the greater the voltage difference between the pixel electrodes 118, the greater the degree of domains generated near the boundary between two adjacent panel pixels. The panel pixels that have generated domains will not have a transmittance corresponding to the grayscale level, and therefore become the main reason for reducing the display quality.

[0091] Therefore, if only suppressing display defects caused by domains is considered, when a bright panel pixel Lp is adjacent to a dark panel pixel Dp, correction should be performed in a manner that reduces the lateral electric field generated in the pixel electrode 118 of the bright panel pixel Lp and the pixel electrode 118 of the dark panel pixel Dp.

[0092] However, in the configuration of shifting the projection position of the panel pixels using the optical path shift element 230 , even if the video image specified by the video data Vid_in is a static image, the grayscale level may change like a dynamic image when viewed from the panel pixels of the liquid crystal panel 100 .

[0093] In addition, the case where the video image is a static image means that the grayscale level of the video pixel does not change when the previous and next frames are compared.

[0094] For example, taking the image pixels as a static image Fig.12 Specifically, the grayscale levels of the image pixels A1 and A2 are the lowest black level, and the grayscale levels of the other image pixels B1, B2, C1, C2, D1, D2, E1, E2, F2, and F1 are the highest white level.

[0095] In this case, if Fig.12 As shown in the upper right column of , panel pixel a1 represents image pixel A1 in unit period f1, image pixel A2 in unit period f2, image pixel B2 in unit period f3, and image pixel B1 in unit period f4. Panel pixel b1 represents image pixel C1 in unit period f1, image pixel C2 in unit period f2, image pixel D2 in unit period f3, and image pixel D1 in unit period f4. Panel pixel c1 represents image pixel E1 in unit period f1, image pixel E2 in unit period f2, image pixel F2 in unit period f3, and image pixel F1 in unit period f4.

[0096] In the unit period f1, the grayscale level of the image pixel A1 corresponding to the panel pixel a1 is black, and the grayscale level of the image pixel C1 corresponding to the panel pixel b1 adjacent to the panel pixel a is white. Therefore, the panel pixel a1 becomes a dark panel pixel, and the panel pixel b1 becomes a bright panel pixel, so domain correction is performed. Specifically, the following correction is performed: Fig.12 As shown in the middle left column of , the grayscale level of image pixel A1 is increased from the lowest value, and the grayscale level of image pixel C1 is reduced from the highest value.

[0097] When looking at the arrangement of image pixels, with respect to an image pixel corresponding to a certain panel pixel, the image pixels of the panel pixels adjacent to the panel pixel refer to image pixels located in the same column of the upper 2 rows, image pixels located in the same column of the lower 2 rows, image pixels located in the left 2 columns of the same row, and image pixels located in the right 2 columns of the same row.

[0098] For example, in Figure 5 In the case where the panel pixel b2 represents the image pixel C3 in the unit period f1, the image pixels represented by the panel pixels a2, c2, b1 and b3 adjacent to the panel pixel b2 are, respectively, the image pixel A3 located in the same column 2 rows above the image pixel C3, the image pixel E3 located in the same column 2 rows below the image pixel C3, the image pixel C1 located 2 columns to the left of the same row, and the image pixel C5 located 2 columns to the right of the same row.

[0099] Therefore, when a certain image pixel is represented by a panel pixel, whether domain correction is required can be determined by comparing the grayscale level of the image pixel with the grayscale levels of the next four image pixels. In addition, the four image pixels relative to a certain image pixel are, as described above, image pixels located in the same column of the upper two rows, image pixels located in the same column of the lower two rows, image pixels located in the left two columns of the same row, and image pixels located in the right two columns of the same row.

[0100] Assume that the voltage applied to the liquid crystal element 120 corresponding to the lowest black level is 0 V (volt), and the voltage applied to the liquid crystal element 120 corresponding to the highest white level is 5 V. In domain correction, Fig.12 As shown in the middle right column, the grayscale levels of the image pixels A1 and C1 are corrected individually so that the applied voltage of the liquid crystal element 120 of the panel pixel a1 in the unit period f1 becomes, for example, 1.8V, and the applied voltage of the liquid crystal element 120 of the panel pixel b1 becomes, for example, 4.6V.

[0101] In addition, in the unit period f1, the grayscale level of the image pixel C1 corresponding to the panel pixel b1 and the grayscale level of the image pixel E1 corresponding to the panel pixel c1 are both bright panel pixels, and therefore, domain correction is not performed.

[0102] In unit period f2, panel pixel a1 is a dark panel pixel and panel pixel b1 is a bright panel pixel, so the same domain correction is performed. In addition, in unit period f2, panel pixels b1 and c1 are both bright panel pixels, so domain correction is not performed.

[0103] In the unit period f3, panel pixels a1, b1 and c1 are all bright panel pixels, so domain correction is not performed. Similarly, in the unit period f4, panel pixels a1, b1 and c1 are all bright panel pixels, so domain correction is not performed.

[0104] However, in the liquid crystal panel 100, the optical responsiveness of the liquid crystal element 120 to electrical changes is lower than that of other display elements such as organic EL elements. In order to compensate for the low optical responsiveness, a technique such as overdrive is sometimes applied to the liquid crystal panel 100. In detail, overdrive refers to a technique in which, for example, in a certain image pixel, when there is a change in grayscale level from the previous unit period to the current unit period, a voltage that oscillates excessively in the direction of grayscale level change compared to the grayscale level specified in the current unit period is applied to the liquid crystal element 120 of the panel pixel corresponding to the image pixel in the current unit period.

[0105] However, if overdrive is applied to a structure that performs domain correction and uses the optical path shift element 230 , the following disadvantages occur.

[0106] That is, Fig.12 As shown in the lower right column of , when returning from unit period f4 to unit period f1, in panel pixel a1, the grayscale level of image pixel B1, i.e., the highest value, changes to the grayscale level of image pixel A1, i.e., the lowest value, increased by domain correction. Therefore, the grayscale level of image pixel A1 in unit period f1 is subjected to a relatively strong correction in the direction of decreasing due to overdrive, but in domain correction, the grayscale level is corrected in the direction of increasing as described above. Therefore, an undesirable situation occurs in which domain correction and overdrive correction cancel each other out.

[0107] Specifically, in the unit period f1, the voltage applied to the liquid crystal element 120 of the panel pixel a1 is increased from 0 V to 1.8 V by domain correction, but is reduced by α V by overdrive. Therefore, the corrections by domain correction and overdrive cancel each other out.

[0108] In this embodiment, as a first countermeasure, domain correction is performed in such a way that the intensity of the lateral electric field in the dark panel pixel and the bright panel pixel in a certain unit period is smaller than the voltage difference corresponding to the grayscale level specified by the image data. The domain correction of this first countermeasure itself is the same as the above-mentioned conventional domain correction, so in this state, the correction effect is offset by overdrive.

[0109] Therefore, the following first correction, second correction, or third correction is added to the first countermeasure.

[0110] The first correction refers to the following correction: when viewed from the arrangement of image pixels, the grayscale levels of three consecutive image pixels adjacent to the image pixel corresponding to the dark panel pixel in the first specific direction are made consistent with the grayscale level of the image pixel to which the domain correction is applied. In addition, the first specific direction mentioned here refers to the direction in which the image pixel corresponding to the bright panel pixel is located with respect to the image pixel corresponding to the dark panel pixel as a reference.

[0111] The second correction refers to the following correction: when viewed from the arrangement of image pixels, the grayscale levels of three consecutive image pixels adjacent to the image pixel corresponding to the bright panel pixel in the second specific direction are made consistent with the grayscale level of the image pixel to which the domain correction is applied. In addition, the second specific direction referred to here refers to the direction in which the image pixel corresponding to the dark panel pixel is located with respect to the image pixel corresponding to the bright panel pixel as a reference.

[0112] The third correction is correction using the first correction and the second correction together.

[0113] First, an example in which the first correction is added to the first countermeasure will be described.

[0114] Fig.13 The lower left and right columns of are diagrams for explaining the case where the first correction is applied. Fig.12 The upper left column and the upper right column are shown again in Fig.13 The upper left column and Fig.13 The upper right column.

[0115] First, take the first countermeasure Fig.12 The upper left column or Fig.13 The arrangement of image pixels shown in the upper left column has been domain corrected as an example. Fig.12 As shown in the middle left column of .

[0116] Specifically, in the arrangement of image pixels, with respect to image pixel A1 having the lowest grayscale value, image pixel C1 located in the same column two rows below has the highest grayscale value, and therefore, correction is performed to increase the grayscale level of image pixel A1 from the lowest value and to decrease the grayscale level of image pixel C1 from the highest value. Similarly, with respect to image pixel A2 having the lowest grayscale value, image pixel C2 located in the same column two rows below has the highest grayscale level, and therefore, correction is performed to increase the grayscale level of image pixel A2 and to decrease the grayscale level of image pixel C2.

[0117] Next, the first correction added to the first countermeasure is described. In the arrangement of image pixels, with image pixel A1 corresponding to dark panel pixel a1 as a reference, the first specific direction in which image pixel C1 corresponding to bright panel pixel b1 is located is downward. Therefore, Fig.13 As shown in the lower left column of , the grayscale levels of the three image pixels B1, C1, and D1 that are adjacent and continuous downwardly relative to the image pixel A1 corresponding to the dark panel pixel a1 are consistent. The grayscale level of the image pixel C1 is reduced from the maximum value according to the first countermeasure, so the grayscale levels of the image pixels B1 and D1 are consistent with the grayscale level of the reduced image pixel C1. Similarly, among the grayscale levels of the three image pixels B2, C2, and D2 that are adjacent and continuous downwardly relative to the image pixel A2 corresponding to the dark panel pixel a1, the grayscale levels of the image pixels B2 and D2 are consistent with the grayscale level of the reduced image pixel C2.

[0118] As a result of such a first correction, in the panel pixels a1, b1, c1, as Fig.13 In the unit periods f1 and f2, the domain correction is the same as in the past. The difference is that in the unit periods f3 and f4, the panel pixel a1 represents the image pixels B2 and B1 with increased grayscale levels, and the panel pixel b1 represents the image pixels D2 and D1 with reduced grayscale levels from the unit periods f1 and f2.

[0119] When the first correction is added to the first countermeasure, the voltage applied to the liquid crystal element 120 of the panel pixel a1 in the unit periods f3 and f4 is lower than the voltage corresponding to the highest white level due to the correction for increasing the grayscale level. Therefore, the amount of change in the grayscale level when returning from the unit period f4 to f1 is reduced, and thus the amount of correction for overdrive is also reduced. Therefore, according to the first correction, the ratio of the domain correction offset by the correction for overdrive is reduced, and thus, the situation in which the effect of the domain correction is weakened due to overdrive can be suppressed.

[0120] In addition, in the unit periods f1 and f2, the lateral electric field between the panel pixels a1 and b1 is weakened by the correction of the first countermeasure, and in the unit periods f3 and f4, the panel pixels a1 and b1 become the same potential by the first correction. Therefore, even if display defects caused by domains occur in the unit periods f1 and f2, the display defects will be alleviated as soon as possible.

[0121] Next, an example in which the second correction is added to the first countermeasure will be described.

[0122] Fig.14 The lower left column and the lower right column of are diagrams for explaining the case where the second correction is applied. In addition, for comparison, Fig.14 The upper left column and upper right column of Fig.13 The upper left column and Fig.13 An example of inverting black to white and white to black in the upper right column of FIG.

[0123] First, the first countermeasure before the second correction is described. In the arrangement of image pixels, the grayscale level of the image pixel C1 located in the same column of the next two rows is the lowest value relative to the image pixel A1 having the highest grayscale level. Therefore, in the absence of correction in the unit period f1, domains are generated in the panel pixel a1 representing the image pixel A1 and the panel pixel b1 representing the image pixel C1. Therefore, first, a correction is performed to reduce the grayscale level of the image pixel A1 and increase the grayscale level of the image pixel C1. Similarly, the grayscale level of the image pixel C2 located in the same column of the next two rows is the lowest value relative to the image pixel A2 having the highest grayscale level. Therefore, a correction is performed to reduce the grayscale level of the image pixel A2 and increase the grayscale level of the image pixel C2.

[0124] Next, the second correction is described. In the arrangement of image pixels, with image pixel A1 corresponding to bright panel pixel a1 as a reference, the first specific direction in which image pixel C1 corresponding to bright panel pixel b1 is located is downward. Therefore, Fig.14 As shown in the lower left column of , the grayscale levels of the three image pixels B1, C1, and D1 that are adjacent and continuous downwardly relative to the image pixel A1 corresponding to the dark panel pixel a1 are consistent. The grayscale level of the image pixel C1 is increased from the minimum value by the first countermeasure, so the grayscale levels of the image pixels B1 and D1 are consistent with the grayscale level of the increased image pixel C1. Similarly, among the grayscale levels of the three image pixels B2, C2, and D2 that are adjacent and continuous downwardly relative to the image pixel A2 corresponding to the bright panel pixel a2, the grayscale levels of the image pixels B2 and D2 are consistent with the grayscale level of the increased image pixel C2.

[0125] As a result of such a second correction, in the panel pixels a1, b1, c1, as Fig.14In addition, in the unit periods f1 and f2, the domain correction is the same as in the past. The difference is that in the unit periods f3 and f4, the panel pixel a1 represents the image pixels B2 and B1 with increased grayscale levels, and the panel pixel b1 continues to represent the image pixels D2 and D1 with increased grayscale levels from the unit periods f1 and f2.

[0126] According to the second correction, in the unit periods f3 and f4, the voltage applied to the liquid crystal element 120 of the panel pixel a1 is higher than the voltage corresponding to the lowest black level due to the correction for lowering the grayscale level. Therefore, the amount of change in the grayscale level when returning from the unit period f4 to f1 is reduced, and therefore, the amount of correction for overdrive is also reduced. Therefore, according to the second correction, the ratio of the domain correction offset by the overdrive correction is reduced, and therefore, the situation in which the effect of the domain correction is weakened due to overdrive can be suppressed.

[0127] In addition, in the unit periods f1 and f2, the lateral electric field between the panel pixels a1 and b1 is weakened by the correction of the first countermeasure, and in the unit periods f3 and f4, the panel pixels a1 and b1 become the same potential. Therefore, even if display defects caused by domains occur in the unit periods f1 and f2, the display defects will be alleviated as soon as possible.

[0128] Next, an example in which a third correction using the first correction and the second correction is added to the first countermeasure will be described. Specifically, an example in which the first correction is added to the first countermeasure and the second correction is added to the first countermeasure will be described.

[0129] Fig.15 The lower left and right columns of FIG. 3 are diagrams for explaining the case where the third correction is applied. In addition, in the third correction, the range of image pixels to be corrected is expanded, so Fig.12 The upper column and Fig.13 Compared with the upper column, the arrangement of image pixels is expanded.

[0130] Specifically, there are five consecutive image pixels A1, B1, C1, D1 and E1 with the lowest grayscale values, and five consecutive image pixels F1, G1, H1, I1 and J1 with the highest grayscale values. That is, the image pixel E1 with the lowest grayscale value is adjacent to the image pixel F1 with the highest grayscale value.

[0131] First, the first measure before the first calibration will be described.

[0132] The grayscale level of the image pixel E1 which has the lowest value is the highest value in the same column of the image pixel G1 which is located in the lower two rows. Therefore, in the case where no correction is made in the unit period f1, domains are generated in the panel pixel c1 which represents the image pixel E1 and the panel pixel d1 which represents the image pixel G1, and thus correction is made to increase the grayscale level of the image pixel E1 and decrease the grayscale level of the image pixel G1.

[0133] Next, the first correction after the first countermeasure is described. In the arrangement of image pixels, the first specific direction in which the image pixel G1 is located is downward relative to the image pixel E1. Therefore, the grayscale levels of the three image pixels F1, G1, and H1 that are adjacent and continuous downward relative to the image pixel E1 are consistent. Since the grayscale level of the image pixel G1 has been reduced from the highest value, the grayscale levels of the image pixels F1 and H1 are consistent with the grayscale level of the reduced image pixel G1.

[0134] Next, the first measure before the second correction will be described.

[0135] The grayscale level of the image pixel D1 located in the same column of the upper two rows is the lowest value relative to the image pixel F1 having the highest grayscale level. Therefore, if no correction is made in the unit period f4, domains are generated in the panel pixel c1 representing the image pixel F1 and the panel pixel b1 representing the image pixel D1, and thus correction is made to reduce the grayscale level of the image pixel F1 and increase the grayscale level of the image pixel D1.

[0136] However, since the grayscale level of the image pixel F1 has been lowered, it does not need to be lowered again.

[0137] Next, the second correction after the first countermeasure is described. In the arrangement of the image pixels, the second specific direction in which the image pixel D1 is located is upward relative to the image pixel F1. Therefore, the grayscale levels of the three image pixels C1, D1, and E1 that are adjacent and continuous upward relative to the image pixel F1 are consistent. The grayscale level of the image pixel D1 has been increased from the lowest value, so the grayscale levels of the image pixels C1 and E1 are consistent with the grayscale level of the increased image pixel D1.

[0138] When there are five consecutive image pixels A2, B2, C2, D2 and E2 and five consecutive image pixels F2, G2, H2, I2 and J2 with the highest grayscale values, the grayscale levels are similarly corrected to be consistent.

[0139] In the third correction, the grayscale levels of the image pixels F1, F2, G1, G2, H1, and H2 are reduced from the maximum value, and therefore, the applied voltage of the liquid crystal element 120 in the panel pixels corresponding to these image pixels becomes, for example, 4.6 V, which is slightly lower than the maximum value of 5 V. In addition, the grayscale levels of the image pixels C1, C2, D1, D2, E1, and E2 are increased from the minimum value, and therefore, the applied voltage of the liquid crystal element 120 in the panel pixels corresponding to these image pixels becomes, for example, 1.2 V, which is slightly higher than the minimum value of 0 V.

[0140] When the third correction is performed in addition to the first countermeasure, the number of stages at which the lateral electric field generated in the panel pixel is weakened increases compared to the first correction and the second correction, so the degradation of display quality caused by the domain can be further suppressed. In addition, according to the third correction, when viewed from one panel pixel, the change in grayscale level per unit period becomes smaller, so it is possible to suppress the situation where the effect of domain correction is weakened due to overdriving.

[0141] Next, a specific example of the processing circuits 22R, 22G, and 22B that execute the above-mentioned first correction, second correction, or third correction will be described.

[0142] Fig.16 22 is a block diagram showing the configuration of the processing circuits 22R, 22G, and 22B.

[0143] If the Fig.16 As shown, the processing circuit 22R includes a gamma correction circuit 221 , a domain correction circuit 222 , a continuous correction circuit 224 , a separation circuit 225 and an overdrive correction circuit 226 .

[0144] In the processing circuit 22R, the gamma correction circuit 221 corrects the grayscale specified by Va_R of the R component in the video data Vid_in to the transmittance characteristics of the liquid crystal element 120 and the visual characteristics of the human body. The data after the grayscale specified by the video data Va_R is corrected does not replace the specified grayscale.

[0145] The domain correction circuit 222 focuses on a certain image in the arrangement of image pixels constituting the image data Va_R, and compares the grayscale level of the focused image pixel with the grayscale levels of four adjacent judgment target image pixels in a unit period to determine whether the domain generation condition is satisfied.

[0146] The domain generation condition means: if the grayscale level of the focus image pixel is less than the first threshold, the grayscale level of the object image pixel is judged to be above the second threshold (first condition); and if the grayscale level of the focus image pixel is above the second threshold, the grayscale level of the object image pixel is judged to be less than the first threshold (second condition).

[0147] The first threshold is a grayscale level at which the voltage applied to the liquid crystal element 120 corresponds to VL, and the second threshold is a grayscale level at which the voltage applied to the liquid crystal element 120 corresponds to VH.

[0148] If the first condition among the domain generation conditions is met, the domain correction circuit 222 performs any one of the corrections of increasing the grayscale level of the focus image pixel / reducing the grayscale level of the judgment object pixel / increasing the grayscale level of the focus image pixel and reducing the grayscale level of the judgment object pixel.

[0149] Furthermore, in the present embodiment, if the first condition is satisfied, correction is performed to increase the grayscale level of the target image pixel and to decrease the grayscale level of the determination target pixel.

[0150] If the second condition in the domain generation condition is met, the domain correction circuit 222 performs any one of the corrections of reducing the grayscale level of the focus image pixel / increasing the grayscale level of the judgment object pixel / reducing the grayscale level of the focus image pixel and increasing the grayscale level of the judgment object pixel.

[0151] Furthermore, in the present embodiment, if the second condition is satisfied, correction is performed to lower the grayscale level of the target image pixel and increase the grayscale level of the determination target pixel.

[0152] If the domain generation condition is not satisfied, the domain correction circuit 222 does not correct the grayscale level of the target image pixel and the grayscale level of the determination target pixel.

[0153] In addition, the domain correction circuit 222 performs determination on all the image pixels while sequentially shifting the image pixels of interest in one frame.

[0154] The continuous correction circuit 224 performs the above-mentioned first correction, second correction, or third correction.

[0155] The separation circuit 225 extracts and outputs the image data corresponding to the unit period specified by the control circuit 21 from the arrangement of image pixels.

[0156] The overdrive correction circuit 226 performs overdrive correction on the image data of the current unit period output from the separation circuit 225. Specifically, the overdrive correction circuit 226 compares the grayscale level of the image data of the current unit period with the grayscale level of the image data corresponding to the same panel pixel of the previous unit period, and adds the grayscale level change direction and the correction amount accompanied by positive and negative values ​​according to the change amount to the grayscale level of the image data of the current unit period.

[0157] The image data subjected to overdrive correction is converted into an analog data signal Vid_R by a DA conversion circuit (not shown) and is supplied to the liquid crystal panel 100R.

[0158] In addition, the processing circuits 22G and 22B differ only in the color components of the input image data and the supply destinations of the output data signals, and the configuration itself is the same, so the description thereof is omitted.

[0159] Obviously, the domain correction of the domain correction circuit 222 is a process for reducing the lateral electric field generated in adjacent panel pixels. Therefore, the domain correction circuit 222 can be replaced by a filter processing circuit for smoothing the grayscale of the image pixels.

[0160] Fig.17 2 is a block diagram showing a configuration in which the domain correction circuit 222 is replaced by the filter processing circuit 220. Specifically, Va_R of the R component in the video data Vid_in is processed in the order of the filter processing circuit 220, the gamma correction circuit 221, and the continuity correction circuit 224.

[0161] In this configuration, the filter processing circuit 220 smoothes the grayscale level of the image pixel specified by Va_R of the R component in the image data Vid_in. In addition, the grayscale level is smoothed by, for example, using Fig.18 The coefficient matrix of the filter shown is implemented.

[0162] The coefficient matrix of the filter means the following processing: in the arrangement of image pixels constituting the image data Va_R, when focusing on a certain image image, if the grayscale level of the image pixel of interest is higher than the grayscale levels of the surrounding image pixels, the grayscale level of the image pixel of interest is multiplied by the positive coefficient shown by the bold frame to reduce it, and the grayscale levels of the image pixels located around the image pixel of interest are increased by an amount obtained by multiplying the coefficient corresponding to the position.

[0163] in addition, Fig.18 The coefficients in the coefficient matrix of the filter in are just an example, and are an example of evenly distributing the difference "0.1" (=1-0.9) generated by multiplying the coefficients shown with a bold frame to the 48 image pixels located in the periphery.

[0164] The filter processing circuit 22 smoothes all the image pixels while sequentially shifting the target image pixels in one frame.

[0165] The above-described embodiment can be variously modified or applied as follows.

[0166] In the embodiments, one frame period is divided into four unit periods. That is, the number k of unit periods included in one frame period is described by taking "4" as an example. k is not limited to "4" and may be "2" or more.

[0167] In the embodiment and the like, the projection position of the optical path shift element 230 is circulated clockwise, but may be circulated counterclockwise.

[0168] According to the above-exemplified aspects, for example, the following aspects can be understood.

[0169] A projection display device of one embodiment (embodiment 1) includes: a liquid crystal panel having a plurality of panel pixels, a first panel pixel of the plurality of panel pixels being adjacent to a second panel pixel; an optical path shifting element, which shifts the optical path of projection light projected from the panel pixel to shift the position of the projection pixel; and a display control circuit, which controls the liquid crystal panel and the optical path shifting element, wherein, among image pixel data constituting image data input to the liquid crystal panel and arranged in a matrix, k (k is an integer greater than or equal to 2) image pixel data individually correspond to the first panel pixels within the k unit periods, and k image pixel data individually correspond to the second panel pixels within the k unit periods, and the k image pixel data corresponding to the first panel pixels are different from the k image pixel data corresponding to the second panel pixels, and the display control circuit performs the following control: with respect to the optical path shifting element, , controlling the displacement of the position of the projection pixel in each of the k unit periods, supplying a data signal based on the image pixel data corresponding to the one unit period to the first panel pixel in one of the k unit periods, and supplying a data signal based on the image pixel data corresponding to the one unit period to the second panel pixel, and correcting at least the second grayscale level in the k image pixel data corresponding to the first panel pixel by reducing the difference between the first grayscale level of the first image pixel data corresponding to the one unit period and the second grayscale level of the second image pixel data corresponding to the one unit period, so that the grayscale levels of (k-1) image pixel data that are continuous in the direction in which the second image pixel is located relative to the first image pixel and that include the second image pixel data are consistent with the corrected second grayscale level and are the same value.

[0170] According to the projection display device according to the first aspect, in a configuration in which the projection position is shifted per unit period using the optical path shift element, it is possible to suppress the generation of domains caused by the lateral electric field and prevent degradation of display quality.

[0171] In a specific aspect 2 of aspect 1, the display control circuit corrects the first grayscale in addition to correcting the second grayscale.

[0172] In a specific aspect 3 of aspect 2, the display control circuit corrects the first grayscale and the second grayscale when the first grayscale is lower than a first threshold and the second grayscale is equal to or higher than a second threshold.

[0173] In a specific aspect 4 of aspect 3, the display control circuit corrects a first grayscale level lower than the first threshold to be equal to or higher than the first threshold, and corrects a second grayscale level equal to or higher than the second threshold to be lower than the second threshold.

[0174] In another specific aspect 5 of the aspect 4, the display control circuit performs correction so as to reduce a difference in grayscale levels between adjacent image pixel data among the image pixel data arranged in a matrix.

[0175] In a specific method 6 of any one of methods 1 to 5, k is 4, 4 image pixel data arranged in 2 rows and 2 columns among the image pixel data arranged in a matrix correspond to 1 panel pixel, and the display control circuit causes the optical path shifting element to shift the 4 projection positions clockwise or counterclockwise.

Claims

1. A projection display device, characterized in that: The projection display device comprises: A liquid crystal panel having a plurality of panel pixels, wherein a first panel pixel of the plurality of panel pixels is adjacent to a second panel pixel; an optical path shifting element that shifts the optical path of the projection light projected from the panel pixel to shift the position of the projection pixel; as well as A display control circuit controls the liquid crystal panel and the optical path shifting element, In the image pixel data that constitutes the image data input to the liquid crystal panel and is arranged in a matrix, k pieces of image pixel data correspond to the first panel pixels separately in k unit periods, wherein k is an integer greater than 2, k pieces of image pixel data correspond to the second panel pixels separately in the k unit periods. The k image pixel data corresponding to the first panel pixel are different from the k image pixel data corresponding to the second panel pixel, The display control circuit performs the following control: For the optical path shifting element, the shift of the position of the projection pixel is controlled in each of the k unit periods, In one unit period among the k unit periods, supplying a data signal based on the image pixel data corresponding to the one unit period to the first panel pixel, and supplying a data signal based on the image pixel data corresponding to the one unit period to the second panel pixel, Among the k image pixel data corresponding to the first panel pixel, correcting at least the second grayscale level in such a manner as to reduce a difference between a first grayscale level of the first image pixel data corresponding to the one unit period and a second grayscale level of the second image pixel data corresponding to the one unit period, The grayscale levels of (k-1) image pixel data that are continuous in the direction in which the second image pixel is located relative to the first image pixel and include the second image pixel data are made consistent with the corrected second grayscale level to be the same value.

2. The projection display device according to claim 1, characterized in that: The display control circuit corrects the first grayscale in addition to correcting the second grayscale.

3. The projection display device according to claim 2, characterized in that: The display control circuit corrects the first grayscale and the second grayscale when the first grayscale is less than a first threshold and the second grayscale is greater than or equal to a second threshold.

4. The projection display device according to claim 3, characterized in that: The display control circuit corrects a first grayscale level that is lower than the first threshold to be equal to or higher than the first threshold, and corrects a second grayscale level that is equal to or higher than the second threshold to be lower than the second threshold.

5. The projection display device according to claim 4, characterized in that: The display control circuit performs correction so as to reduce the difference in grayscale levels between adjacent image pixel data among the image pixel data arranged in the matrix.

6. The projection display device according to any one of claims 1 to 5, characterized in that: The k is 4, Among the image pixel data arranged in a matrix, four image pixel data arranged in two rows and two columns correspond to one panel pixel. The display control circuit enables the optical path shifting element to shift the four projection positions clockwise or counterclockwise.

Images