Electro-optical device and electronic apparatus

Abstract

To reduce power consumption and prevent a reduction in display quality.SOLUTION: A series of data lines for supplying an electric potential Vpr1 used in first precharge is made different for every horizontal scanning period (H), and a precharge electric potential substituting second precharge for a certain pixel is taken as the electric potential of a data signal according to a gradation level for a liquid crystal device 120 corresponding to a pixel in proximity to the certain pixel.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an electro-optical device and an electronic device. [Background technology]

[0002] In electro-optical devices using liquid crystal elements or the like as display elements, a data signal with a potential corresponding to a grayscale level is generally supplied to the display elements via a data line. In electro-optical devices, capacitance is parasitic on the data line, and the display elements have capacitive properties, so that when a data signal with a potential corresponding to a grayscale level is supplied to the display elements via the data line, the previously supplied data signal remains. In order to reduce the influence of the data signal remaining on the data line, a technique known as precharging is known, which supplies a predetermined potential to the data line or the like before a data signal with a potential corresponding to the grayscale level is supplied to the data line (see, for example, Patent Document 1).

[0003] This technology is a technology in which a precharge potential is supplied to all data lines, then multiple data lines are selected in sequence, and a data signal with a potential corresponding to the grayscale level is supplied to the selected data lines. Patent Document 1 also describes that the lines (rows) on which precharge is performed and the lines on which precharge is not performed are shifted for each frame (vertical scanning period). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-152609 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the technology described in Patent Document 1 has the problem that the change in potential caused by precharging all the data lines becomes a source of noise. Also, the technology described in Patent Document 1 has the problem that the precharged lines are shifted in a relatively long period called a frame, so that the movement of the luminance difference between the lines that are precharged and the lines that are not precharged is easily visible. [Means for solving the problem]

[0006] In order to solve the above problem, an electro-optical device according to one aspect of the present disclosure includes a plurality of scanning lines, a plurality of data lines divided into blocks of a predetermined number of lines, a plurality of pixels provided corresponding to each intersection of the plurality of scanning lines and the plurality of data lines, and holding a potential of a corresponding one of the data lines when a corresponding one of the scanning lines is selected, a scanning line driving circuit that selects two of the plurality of scanning lines in a horizontal scanning period, a multiplexer that selects a predetermined number of data lines in one block one by one in a time division manner in the horizontal scanning period, and a data signal supplying circuit that supplies a precharge potential or a potential corresponding to a gradation level to the data line selected by the multiplexer, wherein the scanning line driving circuit selects a first scanning line and a second scanning line from the plurality of scanning lines in a first horizontal scanning period, and selects the second scanning line in a second horizontal scanning period after the first horizontal scanning period, and the demultiplexer selects a predetermined number of data lines in one block in a predetermined order in the first horizontal scanning period, and holds a potential of the predetermined number of data lines in the second horizontal scanning period. the data signal supply circuit selects the data lines in an order different from the predetermined order, and during the first horizontal scanning period, when a first specific data line is selected from the predetermined number of data lines, the data signal supply circuit supplies the precharge potential to the first specific data line, and then supplies a potential corresponding to a gradation level of a pixel corresponding to an intersection with the first scanning line and the first specific data line; when a data line other than the first specific data line is selected from the predetermined number of data lines, the data signal supply circuit supplies a potential corresponding to a gradation level of a pixel corresponding to an intersection with the first scanning line and the other data line; during the second horizontal scanning period, when a second specific data line other than the first specific data line is selected from the predetermined number of data lines, the data signal supply circuit supplies the precharge potential to the second specific data line, and then supplies a potential corresponding to a gradation level of a pixel corresponding to an intersection with the second scanning line and the second specific data line; and when a data line other than the second specific data line is selected from the predetermined number of data lines, the data signal supply circuit supplies a potential corresponding to a gradation level of a pixel corresponding to an intersection with the second scanning line and the other data line. [Brief description of the drawings]

[0007] [Figure 1] 1 is a perspective view showing an electro-optical device according to an embodiment. [Diagram 2] FIG. 2 is a block diagram showing an electrical configuration of the electro-optical device. [Diagram 3] FIG. 2 is a diagram illustrating a configuration of a pixel circuit in an electro-optical device. [Figure 4] FIG. 2 is a diagram showing an arrangement of elements provided in an electro-optical device. [Diagram 5] 5A and 5B are diagrams illustrating potentials such as precharge in an electro-optical device. [Figure 6] 5A and 5B are diagrams illustrating the operation of the electro-optical device. [Figure 7] 5A and 5B are diagrams for explaining operations such as precharging in an electro-optical device. [Figure 8] 5A and 5B are diagrams for explaining operations such as precharging in an electro-optical device. [Figure 9] 5A and 5B are diagrams for explaining operations such as precharging in an electro-optical device. [Figure 10] 5A and 5B are diagrams for explaining operations such as precharging in an electro-optical device. [Figure 11] 5A and 5B are diagrams for explaining operations such as precharging in an electro-optical device. [Figure 12] 5A and 5B are diagrams for explaining operations such as precharging in an electro-optical device. [Figure 13] 10A and 10B are diagrams for explaining operations such as precharging in an electro-optical device according to a modified example. [Figure 14] 1 is a diagram showing a projection display device, which is an example of an electronic device using an electro-optical device. [Figure 15] 10A and 10B are diagrams illustrating the operation of an electro-optical device according to a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an electro-optical device according to an embodiment will be described with reference to the drawings. In each drawing, the dimensions and scale of each part are appropriately different from the actual ones. In addition, since the embodiments described below are preferred specific examples, various technically preferable limitations are attached, but the scope of the present disclosure is not limited to these forms unless otherwise specified in the following description to the effect that the present disclosure is limited.

[0009] FIG. 1 is a perspective view showing the configuration of a display module 1 including an electro-optical device 100 according to an embodiment. The electro-optical device 100 is a transmissive liquid crystal panel used as a light valve for a projection display device, a so-called projector. The electro-optical device 100 is housed in a frame-shaped case 72 that opens at a display area 10. One end of an FPC board 74 is connected to the electro-optical device 100. FPC is an abbreviation for Flexible Printed Circuits. A plurality of terminals 76 are provided at the other end of the FPC board 74, and are connected to a higher-level circuit (not shown).

[0010] A display control circuit 30, which is a semiconductor chip, is mounted on the FPC board 74, and video data is supplied from the higher-level circuit in synchronization with a synchronizing signal via a plurality of terminals 76. The video data defines the gradation level of pixels in an image to be displayed, for example, in 8 bits.

[0011] When the electro-optical device 100 is used as a light valve for a liquid crystal projector, transmitted images from three electro-optical devices 100 corresponding to the primary colors R (red), G (green), and B (blue) are synthesized to display a color image, as described below. Therefore, a pixel, which is the smallest unit of a color image, is expressed by additive color mixing of a red subpixel formed by an electro-optical device corresponding to R, a green subpixel formed by an electro-optical device corresponding to G, and a blue subpixel formed by an electro-optical device corresponding to B. However, when it is not necessary to specify the color of the red, green, and blue subpixels or when only brightness is an issue, there is no need to refer to them as subpixels. Therefore, in this explanation, the red, green, and blue subpixels will also be explained as pixels.

[0012] The synchronization signals include a vertical synchronization signal that instructs the pixels arranged in the display area 10 to start vertical scanning, a horizontal synchronization signal that instructs the pixels to start horizontal scanning, and a clock signal that indicates the timing of one pixel of video data. The display control circuit 30 processes the video data and the synchronization signal, and outputs the data signal and the control signal required for driving the electro-optical device 100. The data signal is an analog signal obtained by converting the video data, and the control signal is a signal for controlling the vertical scanning and the horizontal scanning in the electro-optical device 100. The display control circuit 30 may be provided in a higher-level circuit, rather than being mounted on the FPC board 74, and may receive video signals and control signals via terminals .

[0013] 2 is a block diagram showing the electrical configuration of the display module 1. The display module 1 includes an electro-optical device 100 and a display control circuit 30. In the electro-optical device 100, a scanning line driving circuit 130 and a demultiplexer 150 are provided on the periphery of the display area 10. The electro-optical device 100 is configured by sealing liquid crystal between an element substrate on which thin film transistors and the like are formed and an opposing substrate on which a common electrode is formed, and in this embodiment, a scanning line driving circuit 130 and a demultiplexer 150 are formed on the element substrate.

[0014] In the display region 10 of the electro-optical device 100, pixel circuits 110 corresponding to pixels of an image to be displayed are arranged in a matrix. In detail, in the display region 10, m scanning lines 12 are provided extending horizontally in the figure, and (6n) columns of data lines 14, which are grouped into six columns, extend vertically in the figure and are provided electrically insulated from the scanning lines 12. Then, pixel circuits 110 are provided corresponding to intersections of the m scanning lines 12 and the (6n) data lines 14. Therefore, in this embodiment, the pixel circuits 110 are arranged in a matrix of m vertical rows and (6n) horizontal columns.

[0015] Here, m is an integer equal to or greater than 6, and n is an integer equal to or greater than 1. In order to distinguish the rows of the matrix in the scanning lines 12 and the pixel circuits 110, they may be referred to as rows 1, 2, 3, ..., (m-1), m, 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 may be referred to as columns 1, 2, 3, ..., (6n-1), (6n), from the left in the figure.

[0016] For ease of explanation, the configuration of the pixel circuit 110 will be described with reference to Fig. 3. Fig. 3 is a diagram showing an equivalent circuit of a total of four pixel circuits 110 (2 x 2) corresponding to the intersections of two adjacent scanning 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, while its source node is connected to the data line 14, and its drain node is connected to the pixel electrode 118.

[0017] In this description, "connection" means a direct or indirect connection or coupling between two or more elements, and includes, for example, coupling between two or more elements in a semiconductor substrate through different wiring layers and contact holes even if the elements are not directly connected to each other.

[0018] A common electrode 108 is provided for all pixels so as to face the pixel electrode 118. The common electrode 108 has a substantially constant potential LCcom over time. A 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 by the pixel electrode 118, the common electrode 108, and the liquid crystal 105. 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 a capacitance line 107. The capacitance line 107 is maintained at a constant potential over time, for example, the same potential LCcom as the common electrode .

[0019] Returning to FIG. 2, the display control circuit 30 processes the video data and synchronization signals supplied from the upper circuit, and outputs a control signal to the scanning line drive circuit 130, as well as data signals Vid(1), Vid(2), Vid(3), ..., Vid(n) and control signals Sel(1) to Sel(6). The control signals Sel(1) to Sel(6) are supplied via six control signal lines 180.

[0020] The scanning line driving circuit 130 supplies scanning signals individually to m rows of scanning lines 12 under the control of the display control circuit 30. Here, the scanning signal supplied to the first row of scanning line 12 is denoted as Gwr(1), and similarly, scanning signals supplied to the second, third, ..., mth rows of scanning lines 12 are denoted as Gwr(2), Gwr(3), ..., Gwr(m). Note that an integer i between 1 and m may be used to generalize the six consecutive scanning lines 12.

[0021] The display control circuit 30 outputs a control signal for controlling the scanning line driving circuit 130. However, since the control signal to the scanning line driving circuit 130 is not important in this case, only the signal path is illustrated and a detailed description of the control signal is omitted.

[0022] In this embodiment, the (6n) data lines 14 are grouped into groups of six. In order to generalize and explain one group, an integer j is used that is equal to or greater than 1 and equal to or less than n. In this case, six data lines correspond to the j-th group counting from the left in Fig. 2. In detail, the j-th group corresponds to six data lines 14 in the (6j-5)th, (6j-4)th, (6j-3)th, (6j-2)th, (6j-1)th and (6j)th columns. In addition, in order to specify and explain the data lines 14 in the j-th group, the (6j-5)th column may be written as the first series, the (6j-4)th column as the second series, the (6j-3)th column as the third series, and so on, with the (6j)th column as the sixth series, etc. For example, the data line 14 in the (6j-5)th column will be written as the data line 14 in the first series, and the data line 14 in the (6j-4)th column will be written as the data line 14 in the second series.

[0023] The demultiplexer 150 distributes the data signals to the data lines 14 in accordance with the control signals Sel(1) to Sel(6). In detail, the demultiplexer 150 is provided with transistors Q1 to Q6 corresponding to one block. The transistors Q1 to Q6 are n-channel thin film transistors formed in the same manner as the transistor 116 in the pixel circuit 110, and are provided in one-to-one correspondence with the six data lines 14 belonging to the block.

[0024] In the demultiplexer 150, in the j-th block, the source nodes of the transistors Q1 to Q6 are commonly connected, and a data signal Vid(j) corresponding to the j-th block is input to the source node. A control signal Sel(1) is supplied to the gate node of the transistor Q1, and a drain node of the transistor Q1 is connected to a first series of data line 14. A control signal Sel(2) is supplied to the gate node of the transistor Q2, and a drain node of the transistor Q2 is connected to a second series of data line 14. Similarly, a control signal Sel(6) is supplied to the gate node of the transistor Q6, and the drain node of the transistor Q6 is connected to the data line 14 of the sixth group.

[0025] 2 is a diagram showing the electrical configuration of the electro-optical device 100, and in reality, the elements in the electro-optical device 100 are arranged as shown in FIG. In the electro-optical device 100, when the scanning lines 12 extend in the X direction and the data lines 14 extend in the Y direction, if m<6n, the display area 10 has a rectangular shape in which the X direction is longer than the Y direction. One end of the FPC board 74 is connected to one long side of the electro-optical device 100. Between the one end of the FPC board 74 and the display area 10, a demultiplexer 150 is provided.

[0026] A scanning line driving circuit 130 is provided on each of the two sides along the Y direction in the display region 10. That is, two scanning line driving circuits 130 are provided, and a scanning signal is supplied to the scanning line 12 from both ends. The reason for this configuration is that the effect of a delay in the scanning signal on the display can be suppressed compared to the case where the scanning signal is supplied from only one end. The two scanning line driving circuits 130 are supplied with the same control signal from the display control circuit 30. Although the control signals Sel(1) to Sel(6) are supplied from one end in Fig. 2, they are actually supplied from both ends in order to suppress the effect of delay, as shown in Fig. 4, similarly to the scanning signal.

[0027] 5 is a diagram for explaining the potential of a data signal in the electro-optical device 100. When driving the liquid crystal element 120, it is necessary to drive it with an alternating current in order to prevent deterioration of the liquid crystal 105. For this reason, a positive potential on the higher side and a negative potential on the lower side with respect to the amplitude center potential Vcen are alternately switched and applied to the pixel electrode 118. Note that the potential Vcen may be considered to be approximately the same potential as the potential LCcom applied to the common electrode 108.

[0028] In this embodiment, the liquid crystal element 120 is in a normally black mode in which the liquid crystal element 120 displays black at the lowest gradation when no voltage is applied. The positive polarity potential of the data signal potential ranges from a potential Vwt(+) for displaying white at the highest gradation to a potential Vbk(+) for displaying black at the lowest gradation. The negative polarity potential of the data potential ranges from a potential Vwt(-) for displaying white at the highest gradation to a potential Vbk(-) for displaying black at the lowest gradation. In this embodiment, in vertical scanning of the pixel circuits 110, a plane inversion method is used in which the writing polarities to all the liquid crystal elements 120 are all the same.

[0029] In this embodiment, before a data signal having a potential corresponding to the gradation level is supplied to the liquid crystal element 120 via the data line 14, a precharge potential may be applied to the data line 14 and the liquid crystal element 120 via the data signal supply route.

[0030] Before describing the precharge in the electro-optical device 100 according to this embodiment, the precharge in a comparative example will be described. Note that the configuration of the electro-optical device 100 according to the comparative example is the same as in Figures 2 and 3, but the precharge timing and precharge potential are different from those in this embodiment.

[0031] In detail, there are two kinds of precharge potentials in the comparative example, one is a negative potential Vpr1 shown in Fig. 5, and the other is a middle gradation potential Vpr2(+) or Vpr2(-). Of these, the precharge by the potential Vpr1 may be called a first precharge. In this embodiment, the potential Vpr1 is the same potential in positive polarity writing and negative polarity writing, but the potential of the first precharge may be different potentials Vpr1(+) or Vpr1(-) in positive polarity writing and negative polarity writing. The intermediate gradation potential Vpr2(+) is used for precharging before supplying a data signal of a positive potential corresponding to the gradation level, and the potential Vpr2(-) is used for precharging before supplying a data signal of a negative potential corresponding to the gradation level. Note that the precharging with the potential Vpr2(+) or Vpr2(-) is sometimes called the second precharge.

[0032] 15 is a diagram for explaining the operation, particularly precharging, of an electro-optical device 100 according to a comparative example. In the comparative example, the scanning signals Gwr(1) to Gwr(m) output from the scanning line driving circuit 130 in a vertical scanning period (V) are sequentially and exclusively set to H level for each horizontal scanning period (H). Note that the scanning signals for adjacent scanning lines are set to H level in turn, with an isolation period of L level therebetween. In the horizontal scanning period (H) of the i-th row, during the first period (Tb) during which the scanning signal Gwr(i) is at H level, the control signals Sel(1) to Sel(6) go to H level. After the period (Tb) has elapsed, the control signal Sel(1) goes to H level only for the period T2 following the period (Tb), while the other control signals Sel(2) to Sel(6) change to L level. After the period T2 has elapsed and the control signal Sel(1) goes to L level, the control signal Sel(2) goes to H level only for the period T2. After the period T2 has elapsed and the control signal Sel(2) goes to L level, the control signals Sel(3) to Sel(6) go to H level exclusively in this order for the period T2.

[0033] The period Tb is divided into two periods: a period (Pr1) which precedes the period Tb in time, and a period (Pr2) which follows the period Tb in time. During this period (Pr1), all of the data lines 14 and the liquid crystal elements 120 (the pixel electrodes 118 thereof) are precharged to the potential Vpr1. In detail, in the i-th row, during a period in which the scanning signal Gwr(i) is at the H level, the display control circuit 30 sets the data signals Vid(1) to Vid(6) to the potential Vpr1 during the period (Pr1) of the period (Tb) in which the control signals Sel(1) to Sel(6) are at the H level.

[0034] As a result, in the i-th row, the data lines 14 and liquid crystal elements 120 in columns (6j-5) to (6j) are precharged to a negative potential Vpr1. Note that although the j-th block has been described here, a similar operation is performed in all blocks from 1 to n. Therefore, in period (Pr1) of the horizontal scanning period (H) of the i-th row, a negative potential Vpr1 is supplied to the data lines 14 and liquid crystal elements 120 in columns 1 to (6n) of the i-th row, and charge leakage is uniformed in the liquid crystal elements 120.

[0035] In the period (Pr2), all the data lines 14 and the liquid crystal elements 120 are precharged to a potential Vpr2(+) or a potential Vpr2(-). In particular, when the data signal corresponding to the grayscale level is to have a positive polarity, the display control circuit 30 sets the data signals Vid(1) to Vid(6) to a potential Vpr2(+) in the period (Pr2) during the period (Tb) in which the control signals Sel(1) to Sel(6) are at the H level. In addition, when the data signal corresponding to the grayscale level is to have a negative polarity, the display control circuit 30 sets the data signals Vid(1) to Vid(6) to a potential Vpr2(-) in the period (Pr2).

[0036] As a result, in the i-th row, the data lines 14 and liquid crystal elements 120 in columns (6j-5) to (6j) are precharged to a potential Vpr2(+) or Vpr(-). Note that although the j-th block has been described here, a similar operation is performed in all blocks from the 1st to the nth. During period (Pr2) of the i-th row horizontal scanning period (H), an intermediate potential Vpr2(+) or Vpr(-) corresponding to the polarity of the data signal corresponding to the next grayscale level is supplied to the liquid crystal elements 120 in the i-th row and columns 1 to (6n). In the figure, the period (T2) during which a data signal of a potential corresponding to a grayscale level is supplied is denoted as Vid.

[0037] During the period when the scanning signal Gwr(i) is at H level, in the period (T2) when only the control signal Sel(1) is at H level after the period (Pr2), the display control circuit 30 outputs the data signal Vid(j) to the jth block as a potential corresponding to the gradation level of the pixel in the i-th row (6j-5) column. As a result, the liquid crystal element 120 in the (6j-5) column is supplied with a potential corresponding to the gradation level, so that the liquid crystal element 120 has a transmittance corresponding to the gradation level. Note that although the jth block has been described here, the same operation is performed in all blocks from the 1st to the nth. Therefore, in the period (T2), the liquid crystal element 120 corresponding to the intersection of the i-th row scanning line 12 and the first series data line 14 has a transmittance corresponding to the gradation level. Similarly, the liquid crystal elements 120 corresponding to the intersections of the second to sixth data lines on the i-th row of the scanning line successively have transmittances according to the grayscale levels. Although the horizontal scanning period (H) of the i-th row has been described here, the same operation is executed in the horizontal scanning periods (H) of the 1st row to the m-th row.

[0038] In the comparative example, the first precharge equalizes the leakage of electric charge from the liquid crystal element 120, thereby reducing differences in transmittance that occur depending on the position on the screen, i.e., brightness unevenness. Also, in the comparative example, the second precharge writes a potential corresponding to a grayscale level in accordance with the write polarity in the liquid crystal element 120, and then writes a potential corresponding to the grayscale level, so that the burden of writing to the liquid crystal element 120, i.e., the amount of charging and discharging to the liquid crystal element 120, can be expected to be reduced. However, in the comparative example, the first precharge is performed simultaneously on all data lines in columns 1 to (6n), and then the second precharge is performed simultaneously. That is, all data lines 14 and liquid crystal elements 120 are changed to potential Vpr1 by the first precharge, and changed to potential Vpr2(+) or Vpr2(-) by the second precharge. Therefore, in the comparative example, there is a problem that not only does the noise due to the potential change increase, but also the power consumed due to the potential change increases.

[0039] On the other hand, in the comparative example, the first precharge is executed at the beginning of each horizontal scanning period (H), but even if it is thinned out to some extent, that is, even if it is executed once per several horizontal scanning periods, it is expected that luminance unevenness, etc. can be suppressed. Here, if the horizontal scanning period (H) in which the first precharge is executed is fixed, luminance unevenness, etc. continues to occur in the same place and is visually recognized as a difference with the transmittance, thereby degrading the display quality. Furthermore, in the comparative example, although the second precharge is expected to reduce the amount of charging and discharging to the liquid crystal element 120, when the highest gradation level, white, or the lowest gradation level, black, occurs consecutively, the amount of charging and discharging in the liquid crystal element 120 tends to be large.

[0040] Therefore, in this embodiment, the first precharge is made different for each horizontal scanning period (H), and instead of the second precharge, the precharge potential of the liquid crystal element 120 corresponding to a pixel is made into a data signal corresponding to the grayscale level of the liquid crystal element 120 corresponding to a pixel adjacent to the pixel. Note that in this embodiment, as an example of a pixel adjacent to a pixel, a pixel located in the same column and one row above is used.

[0041] 6 to 12 are diagrams for explaining the operation of the electro-optical device according to the embodiment, in particular precharging. In detail, Fig. 6 is a diagram showing waveforms of scanning signals Gwr(1) to Gwr(m) in a vertical scanning period (V), and Figs. 7 to 12 are diagrams showing waveforms of control signals Sel(1) to Sel(6) in six consecutive horizontal scanning periods (H).

[0042] 6, the scanning signal Gwr(1) becomes H level twice with an L level isolation period in between during the first horizontal scanning period (H) and the second horizontal scanning period (H). The scanning signal Gwr(2) becomes H level twice with an L level isolation period in between during the second horizontal scanning period (H) and the third horizontal scanning period (H). Similarly, the scanning signal Gwr(m) becomes H level twice with an L level isolation period in between during the mth horizontal scanning period (H) and the (m+1)th horizontal scanning period (H). In this way, the scanning signals Gwr(1) to Gwr(m) become H level twice in two consecutive horizontal scanning periods (H), with an isolation period of L level therebetween. Of these, the period in which they become H level the first time is designated as Pr3, and the period in which they become H level the second time is designated as Pv.

[0043] When the scanning signal Gwr(i) of the i-th row is at H level in the period (Pv), the scanning signal Gwr(i+1) of the (i+1)th row adjacent to and facing downward from the i-th row is at H level in the period (Pr3). That is, there is a period during which the scanning signal Gwr(i) and the scanning signal Gwr(i+1) supplied to two adjacent scanning lines 12 overlap and are at H level.

[0044] As shown in FIG. 7, in the horizontal scanning period (H) of the i-th row, during the first period (Ta) and period (T1) during the period (Pv) during which the scanning signal Gwr(i) is at the H level, the display control circuit 30 continuously sets only the control signal Sel(1) to the H level. The period (Ta) is a period for performing the first precharge, as in the comparative example. Therefore, during the period (Ta), the display control circuit 30 outputs the data signals Vid(1) to Vid(n) at the potential Vpr1. As a result, in the j-th block, the data line 14 of the (6j-5)th column and the liquid crystal element 120 corresponding to the intersection of the i-th row scanning line 12 and the data line 14 of the (6j-5)th column are precharged to the negative potential Vpr1.

[0045] In the period (T1), the display control circuit 30 outputs the data signal Vid(j) to the jth block at a potential corresponding to the grayscale level of the pixel in the i-th row (6j-5) column. This causes the liquid crystal element 120 in that column to have a transmittance according to the grayscale level.

[0046] In addition, in the period (Ta) and the period (T1), the same operation is performed in all the blocks from 1st to nth. That is, in the period (Ta), the first series data line 14 and the liquid crystal element 120 corresponding to the intersection of the i-th row scanning line 12 and the first series data line 14 are precharged to a negative polarity potential Vpr1. In addition, in the period (T1), the liquid crystal element 120 corresponding to the intersection of the i-th row scanning line 12 and the first series data line 14 has a transmittance according to the grayscale level. After that, the display control circuit 30 sets the control signal Sel(1) to the L level.

[0047] After setting the control signal Sel(1) to the L level, the display control circuit 30 sets only the control signal Sel(2) to the H level for a period (T2). At this time, the display control circuit 30 outputs the data signal Vid(j) to the jth block at a potential corresponding to the grayscale level of the pixel in the i-th row and (6j-4)th column. This causes the liquid crystal element 120 to have a transmittance corresponding to the grayscale level. In addition, during the period when the control signal Sel(2) is at H level, the same operation is performed in all blocks from 1 to n. That is, the liquid crystal element 120 of the pixel circuit corresponding to the intersection of the i-th row scanning line 12 and the second series data line 14 also has a transmittance according to the grayscale level. After that, the display control circuit 30 sets the control signal Sel(2) to the L level.

[0048] After setting the control signal Sel(2) to the L level, the display control circuit 30 sets the control signals Sel(3) to Sel(6) to the H level exclusively in this order for each period (T2). When the control signals Sel(3) to Sel(6) are sequentially set to the H level, the display control circuit 30 outputs the data signal Vid(j) to the jth block at potentials corresponding to the gradation levels of the pixels in the i-th row (6j-3), i-th column (6j-2), i-th column (6j-1), and i-th column (6j). As a result, the liquid crystal element 120 of the pixel circuit corresponding to the intersection of the i-th scanning line 12 and the third to sixth data lines 14 also has a transmittance according to the grayscale level.

[0049] It should be noted in this embodiment that during the period (Pv) in which the scanning signal Gwr(i) is at the H level, the scanning signal Gwr(i+1) also becomes at the H level during the period (Pr3). Therefore, the same potential as that of the liquid crystal elements 120 in the i row and the 1st to (6n)th columns is written in the liquid crystal elements 120 in the (i+1) row and the 1st to (6n)th columns in sequence.

[0050] 8, in the horizontal scanning period (H) of the (i+1)th row, during the initial period (Ta) and period (T1) of the period (Pv) during which the scanning signal Gwr(i+1) is at H level, the display control circuit 30 changes the control signal to be set at H level to Sel(2). In addition, during the period (Ta), the display control circuit 30 outputs the data signals Vid(1) to Vid(n) at potential Vpr1. As a result, in the jth block, for example, the data line 14 in column (6j-4) and the liquid crystal element 120 corresponding to the intersection of the i-th scanning line 12 and the data line 14 in column (6j-4) are precharged to a negative polarity potential Vpr1.

[0051] In the period (T1), the display control circuit 30 outputs the data signal Vid(j) to the jth block at a potential corresponding to the grayscale level of the pixel in the i-th row (6j-4) column, thereby causing the liquid crystal element 120 in that column to have a transmittance according to the grayscale level.

[0052] In addition, in the period (Ta) and the period (T1), the same operation is performed in all the blocks from 1st to nth. That is, in the period (Ta), the second series data line 14 and the liquid crystal element 120 corresponding to the intersection of the i-th row scanning line 12 and the second series data line 14 are precharged to a negative polarity potential Vpr1. In addition, in the period (T1), the liquid crystal element 120 corresponding to the intersection of the i-th row scanning line 12 and the second series data line 14 has a transmittance according to the grayscale level. After that, the display control circuit 30 sets the control signal Sel(2) to the L level.

[0053] After setting the control signal Sel(2) to the L level, the display control circuit 30 sets the control signals Sel(3) to Sel(6) and Sel(1) to the H level exclusively in this order for each period (T2). When the control signal Sel(3) is set to the H level, the display control circuit 30 outputs the data signals Vid(1) to Vid(n) as potentials corresponding to the gradation levels of pixels corresponding to the intersections of the (i+1)th row scanning line 12 and the third series data line 14. Similarly, the display control circuit 30 subsequently outputs the data signals Vid(1) to Vid(n) as potentials corresponding to the gradation levels of pixels corresponding to the intersections of the (i+1)th row scanning line 12 and the fourth, fifth, sixth, and first series data lines 14 when the control signals Sel(4), Sel(5), Sel(6), and Sel(1) are set to the H level in this order. As a result, the liquid crystal element 120 of the pixel circuit corresponding to the intersection of the (i+1)th scanning line 12 and the first to sixth data lines 14 has a transmittance according to the grayscale level.

[0054] Before writing a potential corresponding to the gray scale level to the liquid crystal element 120 corresponding to the intersection of the (i+1)th row scanning line 12 and each series of data line 14, a potential corresponding to the gray scale level of the same column in the adjacent i-th row one row above is precharged. The burden of writing a potential corresponding to the gray scale level to the liquid crystal element 120 in the (i+1)th row is small if it is the same level as the gray scale level or a level close to it.

[0055] The operations of the (i+2)th row and onwards are as shown in Figures 9 to 12. That is, the horizontal scanning period (H) of the (i+2)th row is as shown in Figure 9, the horizontal scanning period (H) of the (i+3)th row is as shown in Figure 10, the horizontal scanning period (H) of the (i+4)th row is as shown in Figure 11, and the horizontal scanning period (H) of the (i+5)th row is as shown in Figure 12. In detail, in the period (Pv) when the scanning signal Gwr(i+2) is at the H level, the control signals Sel(1) to Sel(6) in FIG. 9 are changed to have the same waveforms as the control signals Sel(6), Sel(1) to Sel(5) in FIG. 8, in that order. 10 are changed to the same waveforms as the control signals Sel(6), Sel(1) to Sel(5) in FIG. 9, in the same order, during the period (Pv) when the scanning signal Gwr(i+4) is at the H level, the control signals Sel(1) to Sel(6) in FIG. 11 are changed to the same waveforms as the control signals Sel(6), Sel(1) to Sel(5) in FIG. 10, in the same order, and during the period (Pv) when the scanning signal Gwr(i+5) is at the H level, the control signals Sel(1) to Sel(6) in FIG. 12 are changed to the control signals Sel(6), Sel(1) to Sel(5) in FIG. 11, in the same order. In this way, the columns on which the first precharge is executed shift by one series every horizontal scanning period (H), and when the first precharge is executed on the final, sixth series, the columns on which the first precharge is executed in the next horizontal scanning period return to the first series.

[0056] In an actual embodiment, the length of the period (T1) during which a data signal with a potential corresponding to the gradation level is written to the liquid crystal element 120 that has undergone the first pre-charge is set to be longer than the length of the period (T2) during which a data signal with a potential corresponding to the gradation level is written to the liquid crystal element 120 that has not undergone the first pre-charge. The first non-precharged liquid crystal element 120 is precharged with a data signal corresponding to the grayscale level of the pixel in the same column in the next row up. In contrast, when a potential corresponding to the grayscale level is written to the first precharged liquid crystal element 120, the potential difference may be large. Specifically, when a potential corresponding to the grayscale level is written with positive polarity to the liquid crystal element 120 precharged with a negative polarity potential Vpr1, the potential difference is large. Since the period (T1) is set to be longer than the period (T2), even if the potential difference is large, insufficient writing is prevented when writing a potential according to the gradation level to the liquid crystal element 120.

[0057] In the embodiment, the first row does not have an adjacent row on the upper side. Therefore, when the scanning signal Gwr(1) is at H level in the period (Pr3), the display control circuit 30 is configured to supply the data signal as a potential corresponding to the gradation level of the pixel corresponding to the first row. That is, for the first row only, in the period (Pv) when the scanning signal Gwr(1) is at H level, the data signal of the potential corresponding to the gradation level is supplied as a precharge potential in the period (Pr3).

[0058] In this embodiment, before a data signal of a potential corresponding to the grayscale level is supplied to the liquid crystal elements 120 in a certain row, a data signal corresponding to the grayscale level is written to the liquid crystal elements 120 in the previous row and in the same column as the row in question as a substitute for the second precharge. Therefore, when the grayscale level of the liquid crystal elements 120 in each column in a certain row is the same as or close to the grayscale level of the previous row and in the same column, the burden of writing to the liquid crystal elements 120, that is, the amount of charging or discharging to the liquid crystal elements 120, can be reduced. Specifically, when characters, line drawings, etc. are displayed against a background of the same color, the grayscale levels of adjacent pixels are often the same, so the burden of writing can be reduced compared to the second precharge in the comparative example. In addition, in this embodiment, the frequency of the first precharge is once every six horizontal scanning periods, which is reduced compared to the comparative example in which the frequency is once per horizontal scanning period. In the embodiment, the row on which the first precharge is executed moves every horizontal scanning period, and completes one cycle in six horizontal scanning periods. In other words, luminance unevenness, etc., occurring between the row on which the first precharge is executed and the row on which the first precharge is not executed is difficult to see because it moves every horizontal scanning period, which is shorter than the vertical scanning period. Therefore, the electro-optical device 100 according to this embodiment achieves low power consumption and prevents degradation of display quality.

[0059] The above-described embodiment can be modified or applied in various ways as follows.

[0060] In the embodiment, the number of data lines 14 constituting one block is "6", that is, the number of branches of one data signal in the demultiplexer 150 is "6", but this number may be any number as long as it is two or more.

[0061] In the embodiment, as an alternative to the second precharge, the precharge potential of the liquid crystal element 120 corresponding to a pixel is a data signal corresponding to the gradation level of the pixel located in the same column as the pixel, but the present invention is not limited to this example. For example, the precharge potential of the liquid crystal element 120 corresponding to a pixel may be a data signal corresponding to the gradation level of the pixel located in the same column as the pixel, but ... second row above the pixel. Specifically, when the display control circuit 30 sets the scanning signal Gwr(i) of the i-th row to H level in the period (Pv), the display control circuit 30 sets the scanning signal Gwr(i+2) of the second row below to H level in the period (Pr3). According to this configuration, for example, when displaying a display in which white, which has the highest gradation level, and black, which has the lowest gradation level, are alternately arranged for each row, the burden of writing to the liquid crystal element 120 can be reduced compared to the embodiment.

[0062] In the embodiment, the number of execution cycles of the first precharge is set to six horizontal scanning periods, which is the same as the number of data lines 14 constituting one block, i.e., six, the number of branches in the demultiplexer 150; however, it may be configured to be different. The number of execution cycles of the first precharge may be, for example, three horizontal scanning periods. Specifically, as shown in Fig. 13, in a horizontal scanning period (H) in which the scanning signal Gwr(i) is at H level, the first precharge is executed in the first and fourth series. Although not shown in particular, if the first precharge is executed in the second and fifth series in a horizontal scanning period (H) in which the scanning signal Gwr(i+1) is at H level, and the first precharge is executed in the third and sixth series in a horizontal scanning period (H) in which the scanning signal Gwr(i+2) is at H level, the number of execution cycles of the first precharge becomes three horizontal scanning periods. In general, when the number of execution cycles of the first precharge is expressed as k horizontal scanning periods, k may be any integer multiple of k (excluding "1") that becomes the number of data lines 14 that make up one block.

[0063] In the embodiment, the first precharge is executed in the order of the first series, the second series, the third series, the fourth series, the fifth series, and the sixth series in six consecutive horizontal scanning periods, but the present invention is not limited to this. For example, the first precharge may be executed in the order of the first series, the third series, the fifth series, the second series, the fourth series, and the sixth series in six consecutive horizontal scanning periods.

[0064] In the embodiment, the first series is the series that starts the first precharge first in the horizontal scanning period (H) when the scanning signal Gwr(1) of the first row becomes H level in the vertical scanning period (V), but this is not limited to this. For example, the series that starts the first precharge first may be configured to shift in sequence for each vertical scanning period (V). Specifically, if in a certain vertical scanning period (V), the first precharge is initially started from the first series in a horizontal scanning period (H) in which the scanning signal Gwr(1) becomes H level, in the next vertical scanning period (V), the first precharge may be initially started from the second series in a horizontal scanning period (H) in which the scanning signal Gwr(1) becomes H level.

[0065] Next, a projection display device will be described as an example of an electronic device to which the electro-optical device 100 according to the embodiment is applied.

[0066] 14 is a diagram showing an optical configuration of a projection display device 200. As shown in the figure, the projection display device 200 includes electro-optical devices 100R, 100G, and 100B.

[0067] A lamp unit 2102 consisting of a white light source such as a halogen lamp is provided inside the projection display device 200. The projection light emitted from this lamp unit 2102 is separated into the three primary colors of red (R), green (G) and blue (B) by three mirrors 2106 and two dichroic mirrors 2108 arranged inside. Of these, the R light enters the electro-optical device 100R, the G light enters the electro-optical device 100G, and the B light enters the electro-optical device 100B. 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. For this reason, a relay lens system 2121 consisting of an entrance lens 2122, a relay lens 2123, and an exit lens 2124 is provided in the optical path of B.

[0068] The electro-optical devices 100R, 100G, and 100B are common to the electro-optical device 100 according to the embodiment, but because the colors of the incident light are different, they are distinguished by reference numerals for the sake of convenience. The liquid crystal element of the electro-optical device 100R is driven based on a data signal corresponding to R supplied from a higher-level device, and has a transmittance according to the potential of the data signal. For this reason, in the electro-optical device 100R, an R transmission image is generated by individually controlling the transmittance of the liquid crystal elements. Similarly, in the electro-optical device 100G, a G transmission image is generated based on a data signal corresponding to G, and in the electro-optical device 100B, a B transmission image is generated based on a data signal corresponding to B.

[0069] The transmitted images of each color generated by the electro-optical devices 100R, 100G, and 100B are incident on the dichroic prism 2112 from three directions. In the dichroic prism 2112, the R and B light are refracted at 90 degrees, while the G light travels straight. Therefore, the dichroic prism 2112 combines the images of each color. The combined image by the dichroic prism 2112 is incident on the projection lens 2114. The projection lens 2114 enlarges and projects the combined image onto the screen Scr.

[0070] Note that the transmission images of the electro-optical devices 100R and 100B are projected after being reflected by the dichroic prism 2112, whereas the transmission image of the electro-optical device 100G travels straight ahead and is projected. Therefore, the transmission images of the electro-optical devices 100R and 100B are in a left-right inverted relationship with the transmission image of the electro-optical device 100G.

[0071] Further, although a projection-type display device 200 has been given as an example of an electronic device here, the present invention is not limited to this and can also be applied to, for example, a display panel of a head-mounted display, an electronic viewfinder in a video camera or an interchangeable-lens digital camera, a personal digital assistant, a display unit of a wristwatch, and the like.

[0072] From the above-mentioned exemplary embodiments, the following aspects can be understood, for example.

[0073] An electro-optical device according to one aspect (Aspect 1) includes a plurality of scanning lines, a plurality of data lines divided into blocks of a predetermined number, a plurality of pixels provided corresponding to each intersection of the plurality of scanning lines and the plurality of data lines and holding a potential of a corresponding one of the data lines when a corresponding one of the scanning lines is selected, a scanning line driving circuit that selects two of the plurality of scanning lines in a horizontal scanning period, a demultiplexer that selects the predetermined number of data lines in one block one by one in a time division manner in the horizontal scanning period, and a data signal supplying circuit that supplies a precharge potential or a potential corresponding to a gradation level to the data line selected by the demultiplexer, wherein the scanning line driving circuit selects a first scanning line and a second scanning line from the plurality of scanning lines in a first horizontal scanning period, and selects the second scanning line in a second horizontal scanning period after the first horizontal scanning period, and the demultiplexer selects the predetermined number of data lines in one block in a predetermined order in the first horizontal scanning period, and selects the predetermined number of data lines in the second horizontal scanning period. the data signal supply circuit, when a first specific data line is selected from among the predetermined number of data lines during the first horizontal scanning period, supplies the precharge potential to the first specific data line, and then supplies a potential corresponding to a gradation level of a pixel corresponding to an intersection with the first scanning line and the first specific data line; when a data line other than the first specific data line is selected from among the predetermined number of data lines, supplies a potential corresponding to a gradation level of a pixel corresponding to an intersection with the first scanning line and the other data line; when a second specific data line other than the first specific data line is selected from among the predetermined number of data lines during the second horizontal scanning period, supplies the precharge potential to the second specific data line, and then supplies a potential corresponding to a gradation level of a pixel corresponding to an intersection with the second scanning line and the second specific data line; and when a data line other than the second specific data line is selected from the predetermined number of data lines, supplies a potential corresponding to the gradation level of a pixel corresponding to an intersection with the second scanning line and the other data line. The electro-optical device according to the first aspect achieves low power consumption and prevents degradation of display quality. The liquid crystal element 120 is an example of a pixel, the potential Vprn1 is an example of a precharge potential, and the display control circuit 30 is an example of a data signal supply circuit. A horizontal scanning period (H) in which the scanning signal Gwr(i) is at H level as a period (Pv) is an example of a first horizontal scanning period, the i-th scanning line 12 is an example of a first scanning line, a horizontal scanning period (H) in which the scanning signal Gwr(i+1) is at H level as a period (Pv) is an example of a second horizontal scanning period, and the (i+1)-th scanning line 12 is an example of a second scanning line. The first series of data lines 14 are an example of first specified data lines, and the second series of data lines 14 are an example of second specified data lines.

[0074] In an electro-optical device according to a specific aspect 2 of aspect 1, during the first horizontal scanning period, a first period in which a potential corresponding to the gradation level of a pixel corresponding to an intersection of the first scanning line and the first specific data line is supplied to the first specific data line is longer than a second period in which a potential corresponding to the gradation level of a pixel corresponding to the first scanning line and the other data line is supplied to other data lines other than the first specific data line. According to the electro-optical device of the second aspect, a long period of time is ensured for writing from the precharge potential to a potential corresponding to the gradation level, and therefore insufficient writing is prevented. The period (T1) is an example of a first period, and the period (T2) is an example of a second period.

[0075] In the electro-optical device according to a third specific aspect of the first aspect, the demultiplexer first selects the first specific data line from among a predetermined number of data lines in the one block during the first horizontal scanning period.

[0076] In the electro-optical device according to a fourth specific aspect of the first aspect, the number of the first specific data lines and the second specific data lines is one or more. That is, as shown in FIG. 15, a configuration may be adopted in which precharging is performed on the first data line 14 and the fourth data line 14 during the horizontal scanning period.

[0077] An electronic device according to a fifth aspect of the present invention includes the electro-optical device according to any one of the first to fourth aspects of the present invention. [Explanation of symbols]

[0078] 12...scanning line, 14...data line, 20...display control circuit (data signal supply circuit), 100...electro-optical device, 110...pixel circuit, 120...liquid crystal element, 130...scanning line drive circuit, 150...demultiplexer, 200...projection type display device (electronic device).

Claims

1. A plurality of scan lines; A plurality of data lines divided into blocks of a predetermined number; a plurality of pixels provided corresponding to each intersection of the plurality of scanning lines and the plurality of data lines, the pixels holding a potential of the corresponding one of the data lines when the corresponding one of the scanning lines is selected; a scanning line driving circuit that selects two scanning lines from among the plurality of scanning lines during a horizontal scanning period; a demultiplexer for selecting the predetermined number of data lines in one block one by one in a time division manner during the horizontal scanning period; a data signal supply circuit for supplying a precharge potential or a potential corresponding to a grayscale level to the data line selected by the demultiplexer; Including, The scanning line driving circuit includes: In a first horizontal scanning period, a first scanning line and a second scanning line are selected from the plurality of scanning lines; In a second horizontal scanning period after the first horizontal scanning period, the second scanning line is selected; The demultiplexer includes: during the first horizontal scanning period, selecting the predetermined number of data lines in the one block in a predetermined order; In the second horizontal scanning period, the predetermined number of data lines are selected in an order different from the predetermined order; The data signal supply circuit includes: In the first horizontal scanning period, When a first specific data line is selected from among the predetermined number of data lines, supplying the precharge potential, and then supplying a potential according to a grayscale level of a pixel corresponding to an intersection of the first scanning line and the first specific data line; When a data line other than the first specific data line is selected from among the predetermined number of data lines, a potential corresponding to a grayscale level of a pixel corresponding to an intersection between the first scanning line and the other data line is supplied; In the second horizontal scanning period, supplying the precharge potential to the second specific data line when a second specific data line other than the first specific data line is selected from among the predetermined number of data lines, and then supplying a potential corresponding to a grayscale level of a pixel corresponding to an intersection of the second scanning line and the second specific data line; When a data line other than the second specific data line is selected from among the predetermined number of data lines, a potential corresponding to a grayscale level of a pixel corresponding to an intersection between the second scanning line and the other data line is supplied. Electro-optical device.

2. In the first horizontal scanning period, The first specific data line, A first period for supplying a potential corresponding to a gray level of a pixel corresponding to an intersection of the first scanning line and the first specific data line is To the other data lines other than the first specific data line, A second period in which a potential corresponding to the gray level of the pixel corresponding to the first scanning line and the other data line is supplied long 2. The electro-optical device according to claim 1.

3. The demultiplexer includes: During the first horizontal scanning period, the first specific data line is selected first from among a predetermined number of data lines in the one block.

2. The electro-optical device according to claim 1.

4. The first specific data line and the second specific data line are one or more.

2. The electro-optical device according to claim 1.

5. 5. An electronic device comprising the electro-optical device according to claim 1.

Images