JP7549998B2 - Light source device for display device and liquid crystal display device - Google Patents

Description

This disclosure relates to a light source device for a display device and a liquid crystal display device.

Liquid crystal display devices are used in a wide range of applications, from small mobile phones to large television monitors, taking advantage of their features of low power consumption and high resolution. However, it has been pointed out that the contrast value of a single liquid crystal device in a dark place is at most around 1000 to 2000, which is low compared to the several million:1 ratio of OLED (organic light emitting diode) display devices. When displaying images using an image source with rich black expression, such as recent HDR images, it has been pointed out that the sense of realism is lacking.

To address this issue, it is necessary to significantly increase the contrast ratio of LCD devices. However, as mentioned above, the contrast ratio of conventional LCD devices is at most about 2000:1, and it is not possible to achieve the contrast ratio of tens of thousands:1 or more required for HDR images.

To address these issues in LCD devices, it has been proposed to stack multiple LCD panels (hereafter referred to as "stacking") to reduce the black luminance and improve the contrast ratio. By stacking multiple LCD panels, it is possible to obtain a contrast that exceeds the contrast of a single LCD panel.

A preferred configuration for displaying color in a liquid crystal display device including multiple stacked liquid crystal panels is disclosed, for example, in U.S. Patent Application Publication No. 2007/0242186. The liquid crystal panel closest to the viewer includes a color filter, and a monochrome liquid crystal panel that does not include a color filter is disposed behind it.

US Patent Application Publication No. 2007/0242186

The transmittance of a liquid crystal display device that includes multiple stacked liquid crystal panels is the product of the transmittances of each of the multiple liquid crystal panels. Therefore, if the transmittance of each liquid crystal panel is low, the transmittance of the entire liquid crystal display device will be very small. Therefore, there is a demand for technology that can improve the transmittance of liquid crystal display devices that include multiple stacked liquid crystal panels.

One aspect of the present disclosure is a light source device for a display device, which includes a surface light source and a monochrome liquid crystal panel. The monochrome liquid crystal panel includes a plurality of pixel electrodes. In the plurality of pixel electrodes, adjacent pixel electrodes partially overlap within one pixel. The monochrome liquid crystal panel includes a single region that includes a portion of one pixel electrode in the plurality of pixel electrodes but does not include other pixel electrodes, and an overlap region that includes a portion of each of the adjacent pixel electrodes.

According to one aspect of the present disclosure, the transmittance of a monochrome liquid crystal panel used in a light source device is improved.

1 illustrates a schematic diagram of a liquid crystal display device according to an embodiment. 2 shows an example of a cross-sectional structure of a display area of a color liquid crystal panel. FIG. 11 is a plan view illustrating a comparative example of a configuration of a TFT substrate of a monochrome liquid crystal panel. 2 is a plan view illustrating a configuration example of a TFT substrate of the monochrome liquid crystal panel according to the first embodiment. FIG. 4B shows a cross-sectional view taken along line IVB-IVB' in FIG. 4A. The structure of a pixel electrode and the positional relationship with adjacent pixel electrodes are shown. The structure of other pixel electrodes and their positional relationships with adjacent pixel electrodes are also shown. An example of the relationship between the signal potentials applied to three pixel electrodes and the display gray scales of a plurality of regions is shown. Another example of the relationship between the signal potentials applied to the three pixel electrodes and the display gray scales of a plurality of regions is shown. FIG. 2 is a plan view showing a schematic configuration example of two adjacent pixel electrodes in one pixel electrode row and their peripheral elements. 10 shows a cross-sectional view taken along line AA' in FIG. 11 shows another example of the layout of pixel electrodes. 4 shows another example of the shape of the pixel electrode. 13 shows another example of a pixel electrode layout. In the pixel electrode layout shown in FIG. 13, an example in which both the IPS type and the FFS type are used as driving types will be described. 4 shows another example of the shape of the pixel electrode. 4 shows another example of the shape of the pixel electrode. 4 shows another example of the shape of the pixel electrode. 4 shows another example of the shape of the pixel electrode.

Hereinafter, an embodiment of the present disclosure will be described with reference to the attached drawings. It should be noted that this embodiment is merely one example for realizing the present disclosure and does not limit the technical scope of the present disclosure.

<Embodiment 1>
[Configuration of Liquid Crystal Display Device]
Fig. 1 is a schematic diagram of a liquid crystal display device according to the present embodiment. The liquid crystal display device 10 includes a control device 110 and a liquid crystal display module 130. The liquid crystal display module 130 includes a plurality of stacked liquid crystal panels, and the configuration example of Fig. 1 includes two liquid crystal panels 131 and 132.

The control device 110 converts the image signal received from the outside and generates a signal for displaying an image on the liquid crystal display module 130. The control device 110 transmits the generated signal to the drive circuits 137 and 138 of the liquid crystal panels 131 and 132 of the liquid crystal display module 130, respectively.

The liquid crystal display module 130 includes drive circuits 137 and 138, liquid crystal panels 131 and 132, and a surface light source 133. The liquid crystal panel 131 is a color liquid crystal panel that performs color display. The liquid crystal panel 132 is a monochrome liquid crystal panel that performs monochrome display. The monochrome liquid crystal panel 132 and the surface light source 133 constitute a light source device.

In the configuration example of FIG. 1, the monochrome liquid crystal panel 132 is disposed between the color liquid crystal panel 131 and the surface light source 133. In other configuration examples, the order of the color liquid crystal panel 131 and the monochrome liquid crystal panel 132 may be reversed. In other words, the monochrome liquid crystal panel 132 is disposed closer to the viewer, and the color liquid crystal panel 131 is disposed closer to the surface light source 133.

The driving circuits 137 and 138 respectively drive the color liquid crystal panel 131 and the monochrome liquid crystal panel 132 based on signals received from the control device 110. The surface light source 133 irradiates the monochrome liquid crystal panel 132 with light from its rear side. The monochrome liquid crystal panel 132 controls the amount of transmitted light from the surface light source 133 based on the input driving signal. The light transmitted through the monochrome liquid crystal panel 132 is incident on the color liquid crystal panel 131. The color liquid crystal panel 131 displays an image based on the input driving signal. The viewer observes the display image formed by the light transmitted from the surface light source 133 through the liquid crystal panels 132 and 131.

In the color LCD panel 131, the pixel 141 is composed of three adjacent sub-pixels of the colors red (R), green (G), and blue (B). The pixels 142 in the monochrome LCD panel 132 are not divided into sub-pixels (each pixel is composed of one sub-pixel). In the example of FIG. 1, the pixel size of the color LCD panel 131 and the pixel size of the monochrome LCD panel 132 are the same, and each pixel 141 of the color LCD panel 131 corresponds to each pixel 142 of the monochrome LCD panel 132.

In another example, the pixel size of the color LCD panel 131 and the pixel size of the monochrome LCD panel 132 may be different, and the number of pixels of the color LCD panel 131 and the number of pixels of the monochrome LCD panel 132 may be different. For example, the number of pixels of the color LCD panel 131 may be greater than the number of pixels of the monochrome LCD panel 132. In one example, a predetermined number (e.g., 4 or 16) of pixels of the color LCD panel 131 are arranged so as to overlap each pixel of the monochrome LCD panel 132 in a planar view.

In one implementation, the pixel boundaries of the monochrome liquid crystal panel 132 overlap with the pixel boundaries of the color liquid crystal panel 131 in a planar view. In another example, the pixel boundaries of the monochrome liquid crystal panel 132 do not have to overlap with the pixel boundaries of the color liquid crystal panel 131 in a planar view. The number of pixels of the color liquid crystal panel 131 that overlap with one pixel of the monochrome liquid crystal panel 132 in a planar view may differ between the pixels of the monochrome liquid crystal panel 132.

In the above configuration example, a color filter layer is formed on only one of the multiple liquid crystal panels. This makes it possible to prevent large changes in display brightness that depend on the viewing angle, which are caused by misalignment of the positional relationships of the multiple color filter layers. Note that in this embodiment, the liquid crystal display device can include three or more liquid crystal panels, and can include multiple color liquid crystal panels.

[Color LCD panel configuration]
2 shows an example of a cross-sectional structure in the display region of the color liquid crystal panel 131. The color liquid crystal panel 131 includes a TFT substrate 200 and a counter substrate 250 that faces the TFT substrate 200. A liquid crystal layer 211 is sandwiched between the TFT substrate 200 and the counter substrate 250. The TFT substrate 200 includes an insulating substrate 202. The insulating substrate 202 is an insulating transparent substrate made of glass or resin. The insulating substrate 202 is, for example, rectangular, and one of its main surfaces faces one of the main surfaces of the counter substrate 250. A polarizing plate 201 is attached to the main surface of the insulating substrate 202 opposite the liquid crystal layer 211.

On the main surface of the insulating substrate 202 facing the liquid crystal layer 211, pixel electrodes 203 and common electrodes (also called counter electrodes) 204 are arranged to apply an electric field to the liquid crystal layer 211. Each pair of pixel electrodes 203 and common electrodes 204 applies an electric field to the liquid crystal of one subpixel. The amount of light transmitted through the subpixel changes depending on the applied electric field. A thin film transistor (TFT) array (not shown) is formed on the insulating substrate 202 to select the subpixel to be controlled.

The configuration example shown in FIG. 2 is a lateral electric field control type liquid crystal panel. The lateral electric field control type liquid crystal panel is, for example, an IPS (In-Plane Switching) type or an FFS (Fringe-Field Switching) type liquid crystal panel. In FIG. 2, only the pixel electrode and common electrode of one subpixel out of the multiple subpixels are indicated by the reference numerals 203 and 204, respectively.

An alignment film 205 is laminated so as to cover the electrode layer including the pixel electrode 203 and the common electrode 204. The alignment film 205 is in contact with the liquid crystal layer 211 and determines the alignment state (initial alignment) of the liquid crystal molecules when no electric field is applied.

In the configuration example of FIG. 2, the counter substrate 250 is a CF substrate including a color filter (CF). The counter substrate 250 includes an insulating substrate 241 made of glass or resin. The insulating substrate 241 is, for example, rectangular. A polarizing plate 242 is attached to the main surface of the insulating substrate 241 opposite the liquid crystal layer 211.

A lattice-shaped black matrix 224 that defines pixels is laminated on the main surface of the insulating substrate 241 on the side of the liquid crystal layer 211. A red, green, or blue color filter 223 is formed in the area of each subpixel surrounded by the black matrix 224.

An insulating overcoat layer 222 is laminated on the color filter 223. The overcoat layer 222 may be omitted. An alignment film 221 is laminated on the overcoat layer 222. The alignment film 221 contacts the liquid crystal layer 211 and determines the alignment state (initial alignment) of the liquid crystal molecules when no electric field is applied.

One of the TFT substrate 200 or the counter substrate 250 is the front side where the viewer is present, and the other is the rear side. In other words, the surface light source 133 is disposed on the TFT substrate 200 side or the counter substrate 250 side of the liquid crystal panel shown in FIG. 2.

The liquid crystal layer 211 controls the amount of light transmitted through each subpixel according to the electric field between the pixel electrode 203 and the common electrode 204. The drive circuit 137 selects each subpixel by the corresponding TFT and controls the potentials of the pixel electrode 203 and the common electrode 204. The drive circuit 137 controls the potentials of the pixel electrode 203 and the common electrode 204 of each subpixel according to image data, thereby controlling the amount of light transmitted through the subpixel.

In the configuration of the monochrome liquid crystal panel 132, the color filter 223 and the black matrix 224 are omitted from the configuration example of the color liquid crystal panel 131 shown in FIG. 2. Since the black matrix is not formed, the aperture ratio of the monochrome liquid crystal panel 132 is improved. Furthermore, as described below, the TFT substrate of the monochrome liquid crystal panel 132 has a different configuration from the TFT substrate 200 of the color liquid crystal panel 131.

The color liquid crystal panel 131 and the monochrome liquid crystal panel 132 can be a vertical electric field control liquid crystal panel, such as a TN (Twisted Nematic) or VA (Vertical Alignment) liquid crystal panel, which is different from the horizontal electric field control type liquid crystal panel shown in FIG. 2 or described below. The monochrome liquid crystal panel 132 may also include a black matrix surrounding the pixels (along the pixel boundaries).

[Comparative Example of Monochrome Liquid Crystal Panel]
3 is a plan view showing a comparative example of a TFT substrate of a monochrome liquid crystal panel, which shows four continuous data lines 302A-302D, two continuous gate lines 304A and 304B, and three continuous pixel electrodes 306A, 306B, and 306C of a monochrome liquid crystal panel 300 of the comparative example.

The pixel electrode 306A is surrounded by gate lines 304A and 304B and data lines 302A and 302B. The data line 302A supplies a data signal to the pixel electrode 306A through a TFT controlled by the gate line 304B. The pixel electrode 306B is surrounded by gate lines 304A and 304B and data lines 302B and 302C. The data line 302B supplies a data signal to the pixel electrode 306B through a TFT controlled by the gate line 304B. The pixel electrode 306C is surrounded by gate lines 304A and 304B and data lines 302C and 302D. The data line 302C supplies a data signal to the pixel electrode 306C through a TFT controlled by the gate line 304B.

Each of the pixel electrodes 306A, 306B, and 306C generates an electric field between itself and a common electrode (not shown) to control the amount of light transmitted (brightness) through the corresponding pixel region. In the example of FIG. 3, for example, the pixel region is an area surrounded by adjacent data lines and adjacent gate lines (including the data lines and parts of the gate lines). In the example of FIG. 3, the pixel electrodes 306A, 306B, and 306C are in a horizontal lattice shape and include a rectangular frame and a number of strips arranged at intervals within the frame. The strips extend along the gate lines and are arranged along the data lines. Both ends of each strip are connected to the frame.

The comparative configuration example shown in FIG. 3 controls pixel electrodes 306A, 306B, and 306C independently to control the amount of light transmitted (brightness) of each corresponding pixel. Pixel electrodes 306A, 306B, and 306C are spaced apart from one another, and the amount of light transmitted through each pixel is determined only by the signal potential of the corresponding pixel electrode. As shown in FIG. 3, for example, the pixel of pixel electrode 306A displays white, the pixel of pixel electrode 306B displays black, and the pixel of pixel electrode 306C displays white, each independently.

As mentioned above, a configuration in which the brightness of adjacent pixel electrodes is independently controlled allows for a display with a high contrast ratio between adjacent pixels. However, when a display is performed using multiple stacked LCD panels, a configuration that achieves a high contrast ratio (high spatial frequency) between adjacent pixels, as in this example, can cause the observer's eyes to focus on the monochrome LCD panel, causing a double image to be seen.

For this reason, it is important to blur the image on the monochrome LCD panel using a diffusion process. In order to perform diffusion processing, it is necessary to increase the resolution of the monochrome LCD panel, but this increases the number of data lines and reduces the transmittance (aperture ratio). The transmittance of an LCD display device that includes multiple stacked LCD panels is the product of the transmittances of each of the multiple LCD panels. Therefore, if the transmittance of each LCD panel is low, the transmittance of the entire LCD display device will be very small.

[Pixel electrode layout of monochrome LCD panel]
4A is a plan view showing a schematic configuration example of a TFT substrate of the monochrome liquid crystal panel 132 of this embodiment. The configuration example described below is an FFS type liquid crystal panel. FIG. 4A shows the configuration of a partial region in the display region. Specifically, FIG. 4A shows four continuous data lines 402A to 402D, two continuous gate lines 404A and 404B, five continuous pixel electrodes 406A to 406E, and TFTs 408A, 408B, and 408C corresponding to the pixel electrodes 406A, 406B, and 406C, respectively, of the monochrome liquid crystal panel 132. The monochrome liquid crystal panel 132 further includes a common electrode (not shown) that generates an electric field between the pixel electrodes 406A, 406B, and 406C, respectively.

The monochrome liquid crystal panel 132 includes a plurality of data lines including data lines 402A-402D, each of which extends along the Y axis (an example of the first axis or the second axis) in FIG. 4A and is arranged along the X axis (an example of the second axis or the first axis) perpendicular to the Y axis. The monochrome liquid crystal panel 132 includes a plurality of gate lines including gate lines 404A and 404B, each of which extends along the X axis and is arranged along the Y axis.

Pixel electrodes 406A-406E are consecutive pixel electrodes included in one pixel electrode row consisting of multiple pixel electrodes arranged along the X-axis. The monochrome liquid crystal panel 132 includes multiple pixel electrode rows arranged along the Y-axis. Each of pixel electrodes 406A-406E has a double-tooth comb shape. Pixel electrodes 406A and 406C have the same shape.

Pixel electrodes 406B, 406D, and 406E have the same shape. Pixel electrodes 406A and 406C have shapes different from pixel electrodes 406B, 406D, and 406E. Two types of pixel electrodes having different shapes are alternately arranged along the X-axis. Details of the shapes of the pixel electrodes will be described later.

In the configuration example of FIG. 4A, pixel electrode 406A is disposed between gate lines 404A and 404B. A portion of pixel electrode 406A, including the center portion, is disposed between data lines 402A and 402B. Another portion of pixel electrode 406A is disposed between data line 402A and the data line adjacent to data line 402A on the opposite side of data line 402B. Another portion of pixel electrode 406A is disposed between data line 402B and data line 402C.

The pixel electrode 406B is disposed between the gate lines 404A and 404B. A portion of the pixel electrode 406B, including the center portion, is disposed between the data lines 402B and 402C. Another portion of the pixel electrode 406B is disposed between the data lines 402A and 402B. Another portion of the pixel electrode 406B is disposed between the data lines 402C and 402D.

The pixel electrode 406C is disposed between the gate lines 404A and 404B. A portion of the pixel electrode 406C, including the central portion, is disposed between the data lines 402C and 402D. Another portion of the pixel electrode 406C is disposed between the data line 402B and the data line 402C. Another portion of the pixel electrode 406C is disposed between the data line 402D and the data line adjacent to the data line 402D on the opposite side of the data line 402C.

The data line 402A supplies a data signal to the pixel electrode 406A via the TFT 408A controlled by the gate line 404B. The data line 402B supplies a data signal to the pixel electrode 406B via the TFT 408B controlled by the gate line 404B. The data line 402C supplies a data signal to the pixel electrode 406C via the TFT 408C controlled by the gate line 404B.

In FIG. 4A, one TFT is shown for each pixel electrode. However, a single TFT may not be able to supply a sufficient signal voltage to the pixel electrode within a specified period. In that case, this can be solved by increasing the number of TFTs (for example, to two) and increasing the number of supply paths for the signal voltage. This is the same in subsequent embodiments.

In FIG. 4A, pixel regions 400A, 400B, and 400C are each surrounded by a dashed line. Pixel region 400A corresponding to pixel electrode 406A includes an area surrounded by gate lines 404A and 404B and data lines 402A and 402B. Pixel region 400A further includes parts of those gate lines and data lines. Pixel region 400A includes a part of pixel electrode 406A including the center, as well as parts of adjacent pixel electrodes 406E and 406B on both sides of pixel electrode 406A.

The pixel region 400B corresponding to the pixel electrode 406B includes an area surrounded by the gate lines 404A and 404B and the data lines 402B and 402C. The pixel region 400B further includes a portion of these gate lines and data lines. The pixel region 400B includes a portion of the pixel electrode 406B including the center, as well as portions of the adjacent pixel electrodes 406A and 406C on both sides of the pixel electrode 406B.

The pixel region 400C corresponding to the pixel electrode 406C includes an area surrounded by the gate lines 404A and 404B and the data lines 402C and 402D. The pixel region 400C further includes a portion of these gate lines and data lines. The pixel region 400C includes a portion of the pixel electrode 406C including the center, as well as portions of the adjacent pixel electrodes 406B and 406D on both sides of the pixel electrode 406C.

As shown in FIG. 4A, each pixel electrode partially overlaps with adjacent pixel electrodes on the X-axis. For example, pixel electrode 406B partially overlaps adjacent pixel electrodes 406A and 406C on both sides, and pixel electrode 406C partially overlaps adjacent pixel electrodes 406B and 406D on both sides.

A pixel region includes a central portion of the corresponding pixel electrode, and also includes a portion of the pixel electrode adjacent to the corresponding pixel electrode. In other words, a portion of the adjacent pixel electrodes extends into the pixel region. For example, pixel region 400B includes a portion of electrode 406B, and a portion of each of adjacent pixel electrodes 406A and 406C on either side of it. Pixel region 400C includes a portion of electrode 406C, and a portion of each of adjacent pixel electrodes 406B and 406D on either side of it.

Figure 4B shows a cross-sectional view taken along the line IVB-IVB' in Figure 4A. The liquid crystal panel of this configuration example is an FFS type. The TFT substrate of the monochrome liquid crystal panel 132 includes an insulating substrate 461. The insulating substrate 461 is an insulating transparent substrate made of glass or resin. In Figure 4B, the polarizing plate is omitted. A gate line 404B is formed on the main surface of the insulating substrate 461 facing the liquid crystal layer (not shown in Figure 4B). The gate line 404B has a single-layer or multi-layer structure of a metal or alloy using, for example, Al, Mo, Cr, etc.

A first insulating film (gate insulating film) 462 is formed to cover the gate line 404B. The first insulating film is, for example, a silicon nitride film or a silicon oxide film. A semiconductor film 463 included in the TFT 408A is formed on the first insulating film 462 so as to overlap with the gate line 404B in a planar view. Furthermore, a data line 402B is formed on the first insulating film 462 in contact with the semiconductor film 463. An interconnection portion 464 included in the same metal layer as the data line 402B is formed apart from the data line 402B and in contact with the semiconductor film 463.

The second insulating film 465 and the interlayer insulating film 466 are formed to cover the data line 402B. The second insulating film 465 is, for example, a silicon nitride film or a silicon oxide film, and the interlayer insulating film 466 is, for example, an organic film such as polyimide. The interlayer insulating film 466 may be omitted.

The common electrode 467 is formed on the interlayer insulating film 466. The common electrode 467 is formed of, for example, ITO (Indium Tin Oxide). A third insulating film 468 is formed so as to cover the common electrode 467. The third insulating film 468 is, for example, a silicon nitride film or a silicon oxide film.

A via hole is formed in the third insulating film 468, the second insulating film 465, and the interlayer insulating film 466 so that the interconnection portion 464 is exposed. In the via hole, a via 469 that is continuous with the pixel electrode 406A is in contact with the interconnection portion 464. The via 469 and the pixel electrode 406B are included in the same metal layer as the pixel electrode 406A. The metal layer is formed of, for example, ITO.

In Figures 4A and 4B, pixel electrodes 406A and 406B are formed from the same metal layer. However, if foreign matter adheres between pixel electrodes 406A and 406B during the manufacturing process in the area where they overlap, the electrodes may short-circuit, resulting in display defects. Therefore, to prevent pixel electrodes 406A and 406B from shorting out, they may be formed from different layers.

Figure 5 shows the structure of pixel electrode 406B and its positional relationship with adjacent pixel electrodes 406A and 406C. Pixel electrode 406B has a double-tooth comb shape, and includes a central ridge 501 extending along the Y axis and multiple teeth extending from ridge 501 on either side along the X axis. Pixel electrode 406B includes rows of teeth on both sides of ridge 501, and each row of teeth is made up of multiple teeth arranged at a predetermined interval along the Y axis. Each row of teeth is made up of two types of teeth of different lengths arranged alternately.

In FIG. 5, as an example, two teeth extending from edge portion 501 to the right are indicated by reference numerals 503A and 505A, and two teeth extending from edge portion 501 to the left are indicated by reference numerals 503B and 505B. Teeth 503A and 503B are long teeth, and teeth 505A and 505B are short teeth. For example, the length of the short teeth is approximately half that of the long teeth.

Teeth 503A and 503B are at the same position on the Y axis and have the same length. Teeth 505A and 505B are at the same position on the Y axis and have the same length. Teeth 503A and 503B are at the ends of the tooth rows. Teeth 505A and 505B are adjacent to teeth 503A and 503B, respectively. In each tooth row, long teeth are present at both ends.

In the example structure shown in Figure 5, the long teeth on either side of the ridge 501 are at the same position on the Y axis, but these positions may be different. Similarly, the short teeth are at the same position on the Y axis, but these positions may be different. The number of teeth on either side of the ridge 501 may be the same or different. The tooth rows may include one or two types of teeth with more than one length, and the types of lengths of the teeth that make up the tooth rows on either side may be different. In the example of Figure 5, the width of the teeth (length along the Y axis) is common, but the width may be different between the teeth.

As shown in FIG. 5, pixel region 400B includes a portion of each of two overlap regions 451 and 453, and a single region 452 sandwiched between overlap regions 451 and 453. Overlap region 451, single region 452, and overlap region 453 are aligned along the X-axis.

Single region 452 includes only pixel electrode 406B (part thereof), and no other pixel electrodes are present within single region 452. Specifically, edge portion 501 of pixel electrode 406B and parts of the teeth on both sides of it are included in single region 452. Specifically, the entirety of all short teeth and parts of all long teeth close to edge portion 501 are present within single region 452.

The adjacent pixel electrodes 406A and 406B overlap in an overlap region 451. A part of the overlap region 451 is included in the pixel region 400B, and another part of the overlap region 451 is included in the pixel region 400A. In the overlap region 451, the row of long teeth of the pixel electrode 406A and the row of long teeth of the pixel electrode 406B overlap. In FIG. 5, one long tooth of the pixel electrode 406A is indicated by the reference numeral 521 as an example.

In the overlap region 451, the long teeth of pixel electrode 406A and the long teeth of pixel electrode 406B are arranged to interlock. Each long tooth of pixel electrode 406A fits between adjacent long teeth of pixel electrode 406B. Each long tooth of pixel electrode 406B other than those at both ends fits between adjacent long teeth of pixel electrode 406A. In the overlap region 451, the long teeth of pixel electrode 406B and the long teeth of pixel electrode 406A are arranged alternately along the Y axis.

A portion, including the tip of each long tooth of pixel electrode 406A, exists between adjacent long teeth of pixel electrode 406B. Between adjacent long teeth of pixel electrode 406B, there are short teeth of pixel electrode 406B. In the example of FIG. 5, the short teeth of pixel electrode 406B and the long teeth of pixel electrode 406A are at the same position on the Y axis, and their tips face each other. The positions of the short teeth of pixel electrode 406B and the long teeth of pixel electrode 406A on the Y axis may be different.

Adjacent pixel electrodes 406B and 406C overlap in overlap region 453. A part of overlap region 453 is included in pixel region 400B, and another part of overlap region 453 is included in pixel region 400C. In overlap region 453, the row of long teeth of pixel electrode 406B and the row of long teeth of pixel electrode 406C overlap. In FIG. 5, one long tooth of pixel electrode 406C is indicated by reference numeral 555B as an example.

In the overlap region 453, the long teeth of pixel electrode 406B and the long teeth of pixel electrode 406C are arranged to interlock. Each long tooth of pixel electrode 406C fits between adjacent long teeth of pixel electrode 406B. Each long tooth of pixel electrode 406B other than those at both ends fits between adjacent long teeth of pixel electrode 406C. In the overlap region 453, the long teeth of pixel electrode 406B and the long teeth of pixel electrode 406C are arranged alternately along the Y axis.

A portion, including the tip of each long tooth of pixel electrode 406C, exists between adjacent long teeth of pixel electrode 406B. Between adjacent long teeth of pixel electrode 406B, there is a short tooth of pixel electrode 406B. In the example of FIG. 5, the short tooth of pixel electrode 406B and the long tooth of pixel electrode 406C are at the same position on the Y axis, and their tips face each other. The positions on the Y axis of the short tooth of pixel electrode 406B and the long tooth of pixel electrode 406C may be different.

In the configuration example of FIG. 5, the total area of the tooth-shaped electrodes in the overlapping regions 451 and 453 and the single region 452 is approximately the same. In the configuration example of FIG. 5, the sum of the number of short tooth pairs at the same position on the Y axis of the pixel electrode 406B in the single region 452 and the number of long tooth pairs at the same position on the Y axis is equal to the sum of the number of long teeth of the pixel electrode 406A in the overlapping region 451 and the number of long teeth of the pixel electrode 406B. Similarly, the sum of the number of short tooth pairs and the number of long tooth pairs in the single region 452 is equal to the sum of the number of long teeth of the pixel electrode 406B in the overlapping region 453 and the number of long teeth of the pixel electrode 406C.

In the overlapping regions 451 and 453 of the configuration example in FIG. 5, the areas of the two pixel electrodes are different. Specifically, in the overlapping region 451, the area of pixel electrode 406B (total area of the teeth) is larger than the area of pixel electrode 406A (total area of the teeth), and in the overlapping region 453, the area of pixel electrode 406B is larger than the area of pixel electrode 406C. In other examples, the areas of the two pixel electrodes in the overlapping region may be the same.

Figure 6 shows the structure of pixel electrode 406C and its positional relationship with adjacent pixel electrodes 406B and 406D. Pixel electrode 406C has a double-tooth comb shape, and includes a central ridge portion 551 extending along the Y axis and multiple teeth extending from ridge portion 551 on either side along the X axis. Pixel electrode 406C includes rows of teeth on both sides of ridge portion 551, and each row of teeth is made up of multiple teeth arranged at a predetermined interval along the Y axis. Each row of teeth is made up of two types of teeth of different lengths arranged alternately.

In FIG. 6, as an example, two teeth extending to the right from ridge portion 551 are indicated by reference numerals 553A and 555A, and two teeth extending to the left from ridge portion 551 are indicated by reference numerals 553B and 555B. Teeth 553A and 553B are short teeth, and teeth 555A and 555B are long teeth. For example, the length of the short teeth is approximately half that of the long teeth.

Teeth 553A and 553B are at the same position on the Y axis and have the same length. Teeth 555A and 555B are at the same position on the Y axis and have the same length. Teeth 553A and 553B are at the ends of the tooth rows. Teeth 555A and 555B are adjacent to teeth 553A and 553B, respectively. In each tooth row, short teeth are present at both ends.

In the example structure shown in Figure 6, the short teeth on either side of the ridge 551 are at the same position on the Y axis, but these positions may be different. Similarly, the long teeth are at the same position on the Y axis, but these positions may be different. The number of teeth on either side of the ridge 551 may be the same or different. The tooth rows may include one or two types of teeth with more than one length, and the types of lengths of the teeth that make up the tooth rows on either side may be different. In the example of Figure 6, the width (length along the Y axis) of the teeth is common, but the width may be different between the teeth.

As shown in FIG. 6, pixel region 400C includes a portion of each of two overlap regions 453 and 455, and a single region 454 sandwiched between overlap regions 453 and 455. Overlap region 453, single region 454, and overlap region 455 are aligned along the X-axis.

Single region 454 includes only pixel electrode 406C (part of it), and no other pixel electrodes are present within single region 454. Specifically, edge portion 551 of pixel electrode 406C and parts of the teeth on both sides of it are included in single region 454. Specifically, the entirety of all short teeth and parts of all long teeth close to edge portion 551 are present within single region 454.

As described above, adjacent pixel electrodes 406C and 406B overlap in overlap region 453. A portion, including the tip, of each long tooth of pixel electrode 406B is present between adjacent long teeth of pixel electrode 406C. A short tooth of pixel electrode 406C is present between adjacent long teeth of pixel electrode 406C. In the example of FIG. 6, the short tooth of pixel electrode 406C and the long tooth of pixel electrode 406B are at the same position on the Y axis, and their tips face each other. The positions of the short tooth of pixel electrode 406C and the long tooth of pixel electrode 406B on the Y axis may be different.

The adjacent pixel electrodes 406C and 406D overlap in an overlap region 455. A part of the overlap region 455 is included in the pixel region 400C, and another part of the overlap region 455 is included in the pixel region 400D. In the overlap region 455, the row of long teeth of the pixel electrode 406C and the row of long teeth of the pixel electrode 406D overlap. In FIG. 6, one long tooth of the pixel electrode 406D is indicated by the reference numeral 571 as an example.

In the overlap region 455, the long teeth of pixel electrode 406C and the long teeth of pixel electrode 406D are arranged to interdigitate with each other. Each long tooth of pixel electrode 406C fits between adjacent long teeth of pixel electrode 406D. Each long tooth of pixel electrode 406D other than those at both ends fits between adjacent long teeth of pixel electrode 406C. In the overlap region 455, the long teeth of pixel electrode 406C and the long teeth of pixel electrode 406D are arranged alternately along the Y axis.

A part, including the tip, of the long tooth of pixel electrode 406D is present between the adjacent long teeth of pixel electrode 406C. Between the adjacent long teeth of pixel electrode 406C, the short tooth of pixel electrode 406C is present. In the example of FIG. 6, the short tooth of pixel electrode 406C and the long tooth of pixel electrode 406D are at the same position on the Y axis, and their tips face each other. The positions of the short tooth of pixel electrode 406C and the long tooth of pixel electrode 406D on the Y axis may be different.

In the configuration example of FIG. 6, the total area of the tooth-like electrodes in the overlapping regions 453 and 455 and the single region 454 is approximately the same. In the configuration example of FIG. 6, the sum of the number of short tooth pairs at the same position on the Y axis of pixel electrode 406C in the single region 454 and the number of long tooth pairs at the same position on the Y axis is equal to the sum of the number of long teeth of pixel electrode 406B in the overlapping region 453 and the number of long teeth of pixel electrode 406C. Similarly, the sum of the number of short tooth pairs and the number of long tooth pairs in the single region 454 is equal to the sum of the number of long teeth of pixel electrode 406C in the overlapping region 455 and the number of long teeth of pixel electrode 406D.

In the overlap region 455 of the configuration example of FIG. 6, the total areas of the two pixel electrodes are different. Specifically, in the overlap region 455, the area of pixel electrode 406C (total area of the teeth) is smaller than the area of pixel electrode 406D (total area of the teeth). In other examples, the areas of the two pixel electrodes in the overlap region are the same.

As described above, in each pixel electrode row arranged along a gate line, adjacent pixel electrodes partially overlap. In the pixel electrode row, overlapping regions and single regions are arranged alternately. A part of the overlapping region is included in one of the two adjacent pixel regions, and another part is included in the other adjacent pixel region. A single region is contained within one pixel region.

As described above, each of two adjacent pixel electrodes (parts of each) exists in the overlap region. The drive circuit 138 applies signal potentials of the same polarity for the common potential to the pixel electrode rows arranged along the X-axis, and applies signal potentials of the same or opposite polarity for the common potential to adjacent pixel electrode rows. Since the two pixel electrodes in the overlap region are applied with signal potentials of the same polarity, a signal potential between the signal potentials of the single regions of the two pixel electrodes is applied to the liquid crystal in the overlap region. In other words, the gradation level of the overlap region between the single regions is between the gradation levels of the two single regions. The drive circuit 138 inverts the polarity of the signal potential applied to each electrode every frame.

Figure 7 shows an example of the relationship between the signal potentials applied to the three pixel electrodes 406A, 406B, and 406C and the display gradations of multiple regions. In the example of Figure 7, pixel electrodes 406A and 406C are given a signal potential that displays white (e.g., a potential with the largest difference from the common potential), and pixel electrode 406B is given a signal potential that displays black (e.g., a common potential).

Single regions 450 and 454 of pixel electrodes 406A and 406C display white. Single region 452 of pixel electrode 406B displays black. Overlap region 451 between single region 450 and single region 452, and overlap region 453 between single region 452 and single region 454, display gray, respectively.

In FIG. 5, in the portion where the tooth 521 of the pixel electrode between the single region 452 and the overlapping regions 451 and 453 faces the tooth 505B, and in the portion where the tooth 505A faces the tooth 555B, the electric field due to the signal potential applied to the pixel electrode is discontinuous. Therefore, the orientation of the liquid crystal is also discontinuous, and disclination is likely to occur. In response to this, a liquid crystal orientation control structure (not shown) for controlling the orientation direction of the liquid crystal may be formed at the tip of the tooth of the pixel electrode. This is the same in the configuration example of FIG. 6 and the examples described later. This liquid crystal orientation control structure makes it possible to display without disclination according to the signal potential, as shown in FIG. 7.

Figure 8 shows another example of the relationship between the signal potentials applied to the three pixel electrodes 406A, 406B, and 406C and the display gradations of the multiple regions. In the example of Figure 8, pixel electrodes 406A, 406B, and 406C are given a signal potential that displays white. Single regions 450, 42, and 454 and overlapping regions 451 and 453 each display white. A similar explanation can be applied to the display of black.

As described above, when two adjacent pixel electrodes are given signal potentials of different gradation levels, the overlapping region displays a gradation level between the gradation levels of the single regions on either side. When two adjacent pixel electrodes are given signal potentials of the same gradation level, the overlapping region displays a gradation level that is the same as the gradation level of the single regions on either side, and the two corresponding pixels as a whole can display the correct gradation level.

As described above, blurring can be performed without increasing the number of data lines in order to increase the resolution of the monochrome liquid crystal panel, and a decrease in the transmittance of the monochrome liquid crystal panel can be avoided. In addition, the load of the image diffusion process of the monochrome liquid crystal panel 132 by the control device 110 can be reduced. Furthermore, this configuration eliminates the need for a black matrix that is provided to prevent light leakage between adjacent pixels, making it possible to increase the aperture ratio (transmittance).

<Other embodiments>
9 is a plan view showing a schematic configuration example of two adjacent pixel electrodes 601A and 601B in one pixel electrode row and their peripheral elements. The pixel electrodes 601A and 601B are disposed between adjacent gate lines 604A and 604B. The pixel electrodes 601A and 601B have a double-tooth comb shape, and include a tooth row in which two types of teeth with different lengths are alternately arranged on both sides of a central ridge extending along the Y axis. In the pixel electrode 601A, the short tooth is located at the upper end, and the long tooth is located at the lower end. In the pixel electrode 601B, the long tooth is located at the upper end, and the short tooth is located at the lower end. The tips of the long and short teeth of each other face each other along the X axis.

Figure 9 is a modified example of Figure 4A, in which the edge of pixel electrode 601A overlaps with data line 602A in a plan view, and the edge of pixel electrode 601B overlaps with data line 602B in a plan view. Data line 602A provides a signal potential to pixel electrode 601A via TFT 603A controlled by gate line 604B. Data line 602B provides a signal potential to pixel electrode 601B via TFT 603B controlled by gate line 604B.

Pixel electrodes 601A and 601B have the same shape, but are inverted upside down in the Y-axis direction. As in the configuration example described with reference to Figures 5 and 6, the rows of long teeth of pixel electrodes 601A and 601B overlap in an overlapping region 605 so as to mesh with each other. In the overlapping region 605, the portions including the tips of each tooth of pixel electrodes 601A and 601B are located between the adjacent long teeth of the other pixel electrode or between the long teeth and the gate line.

Figure 10 shows a cross-sectional view taken along the line A-A' in Figure 9. The liquid crystal panel of this configuration example is an FFS type. The TFT substrate of the monochrome liquid crystal panel 132 includes an insulating substrate 651. The insulating substrate 651 is an insulating transparent substrate made of glass or resin. In Figure 10, the polarizing plate is omitted. A gate line 604B is formed on the main surface of the insulating substrate 651 facing the liquid crystal layer (not shown in Figure 10). The gate line 604B has a single-layer or multi-layer structure of a metal or alloy using, for example, Al, Mo, Cr, etc.

A first insulating film (gate insulating film) 652 is formed to cover the gate line 604B. The first insulating film is, for example, a silicon nitride film or a silicon oxide film. A semiconductor film 653 included in the TFT 603A is formed on the first insulating film 652 so as to overlap with the gate line 604B in a planar view. Furthermore, a data line 602A is formed on the first insulating film 652 in contact with the semiconductor film 653. An interconnection portion 654 included in the same metal layer as the data line 602A is formed apart from the data line 602A and in contact with the semiconductor film 653.

The second insulating film 655 and the interlayer insulating film 656 are formed to cover the data line 602A. The second insulating film 655 is, for example, a silicon nitride film or a silicon oxide film, and the interlayer insulating film 656 is, for example, an organic film such as polyimide. The interlayer insulating film 656 may be omitted.

A common electrode 657 is formed on the interlayer insulating film 656. The common electrode 657 is formed of, for example, ITO. A third insulating film 658 is formed so as to cover the common electrode 657. The third insulating film 658 is, for example, a silicon nitride film or a silicon oxide film.

A via hole is formed in the third insulating film 658, the second insulating film 655, and the interlayer insulating film 656 so that the interconnection portion 654 is exposed. In the via hole, a via 659 that is continuous with the pixel electrode 601A is in contact with the interconnection portion 654. The via 659 and the pixel electrode 601B are included in the same metal layer as the pixel electrode 601A. The metal layer is formed of, for example, ITO.

Figure 11 shows another example of the layout of pixel electrodes. Below, the differences from the configuration example shown in Figure 4A will be mainly explained. Unlike the configuration example shown in Figure 4A, in the pixel electrode columns arranged along the data lines, adjacent pixel electrodes partially overlap.

Figure 11 shows three pixel electrodes 701A, 701B, and 701C that are continuous along the data line (Y axis). The shapes of pixel electrodes 701A and 701C are similar to the shapes of pixel electrodes 401A and 401C described with reference to Figure 4A. The shape of pixel electrode 701B is similar to the shape of pixel electrode 401B described with reference to Figure 4A.

The orientation of pixel electrodes 701A, 701B, and 701C relative to the data lines and gate lines is rotated by 90° relative to the pixel electrodes described with reference to FIG. 4A. The ridges of pixel electrodes 701A, 701B, and 701C extend along the gate lines (X-axis) and the teeth extend along the data lines (Y-axis). Pixel electrodes 701A, 701B, and 701C are disposed between adjacent data lines 702A and 702C. The ridges of pixel electrodes 701A, 701B, and 701C overlap gate lines 704A, 704B, and 704C, respectively, in a plan view.

The tooth rows of pixel electrodes 701A and 701B overlap in overlap region 711. The overlapping state of the tooth rows is as described with reference to Figures 5 and 6. In the example of Figure 11, the teeth of pixel electrodes 701B and 701A are arranged alternately along the gate line.

The single region 712 includes a portion of the pixel electrode 701B, but does not include other pixel electrodes. Specifically, the single region 712 includes the ridge portion of the pixel electrode 701B, the entire portion of the short tooth portion, and the portion close to the ridge portion of the long tooth.

The tooth rows of pixel electrodes 701B and 701C overlap in overlap region 713. The overlapping state of the tooth rows is as described with reference to Figures 5 and 6. In the example of Figure 11, the teeth of pixel electrodes 701B and 701C are arranged alternately along the gate line.

In the configuration example of FIG. 11, overlapping regions and single regions are arranged alternately in each pixel electrode column. Each single region includes a part of the corresponding pixel electrode, and does not include other parts of the pixel electrode and other pixel electrodes. Each overlapping region includes teeth of two pixel electrodes adjacent along the data line, and these teeth are arranged alternately along the gate line. The total areas of the tooth-like electrodes in the overlapping regions and the single regions are approximately the same.

As described above, in pixel electrode rows arranged along the Y axis (data line), each of two adjacent pixel electrodes (parts of each) exists in an overlapping region. The drive circuit 138 applies signal potentials of the same polarity for the common potential to the pixel electrode rows arranged along the Y axis, and applies signal potentials of the same or opposite polarity for the common potential to adjacent pixel electrode rows. The drive circuit 138 inverts the polarity of the signal potential applied to each electrode for each frame.

The two pixel electrodes in the overlap region are given a signal potential of the same polarity, so a signal potential between the signal potentials of the single regions of the two pixel electrodes is given to the liquid crystal in the overlap region. In other words, the gradation level of the overlap region between the single regions is between the gradation levels of the two single regions. Also, when two adjacent pixel electrodes are given a signal potential of the same gradation level, the overlap region displays the same gradation level as the gradation level of the single regions on either side, and the two corresponding pixels as a whole can display the correct gradation level.

As shown in Figures 4A and 11, in both a pixel electrode line (pixel electrode row) consisting of pixel electrodes arranged along a data line and a pixel electrode line (pixel electrode column) consisting of pixel electrodes arranged along a gate line, the pixel electrodes can be arranged so that adjacent pixel electrodes partially overlap.

Figure 12 shows another example of pixel electrode shape. Below, differences from the configuration example shown in Figure 11 will be mainly explained. The arrangement of the teeth of pixel electrode 751A is different from the arrangement of the teeth of pixel electrode 701A, but the other parts are similar. The arrangement of the teeth of pixel electrode 751B is different from the arrangement of the teeth of pixel electrode 701B, but the other parts are similar. The arrangement of the teeth of pixel electrode 751C is different from the arrangement of the teeth of pixel electrode 701C, but the other parts are similar.

In FIG. 12, one of the short teeth of pixel electrode 751A is indicated by reference numeral 753A as an example, and one of the long teeth is indicated by reference numeral 755A as an example. One of the short teeth of pixel electrode 751B is indicated by reference numeral 753B as an example, and one of the long teeth is indicated by reference numeral 755B as an example. One of the short teeth of pixel electrode 751C is indicated by reference numeral 753C as an example, and one of the long teeth is indicated by reference numeral 755C as an example. Pixel electrodes 751A and 751C have the same shape.

The tooth row of pixel electrode 751A is arranged such that groups of three consecutive short teeth alternate with groups of three consecutive long teeth. The tooth row of pixel electrode 751B is arranged such that groups of three consecutive long teeth alternate with groups of three consecutive short teeth. The tooth row of pixel electrode 751C is arranged such that groups of three consecutive short teeth alternate with groups of three consecutive long teeth.

In the overlapping region 761, a first group consisting of each of the three long teeth of pixel electrode 751B and a second group consisting of each of the three long teeth of pixel electrode 751A are arranged alternately. In the overlapping region 763, a first group consisting of each of the three long teeth of pixel electrode 751B and a second group consisting of each of the three long teeth of pixel electrode 751C are arranged alternately. The arrangement of pixel electrodes in the single region 762 is the same as the configuration example shown in FIG. 11.

As described above, in the overlapping regions 761 and 763 of the configuration example in FIG. 12, the teeth of two adjacent pixel electrodes are arranged alternately, with multiple teeth per tooth. In the configuration example shown in FIG. 12, the areas of the two pixel electrodes in the overlapping regions 761 and 763 are the same. Specifically, in the overlapping region 761, the number of teeth and the area of each tooth of pixel electrode 751A are the same as the number of teeth and the area of each tooth of pixel electrode 751B. Similarly, in the overlapping region 763, the number of teeth and the area of each tooth of pixel electrode 751C are the same as the number of teeth and the area of each tooth of pixel electrode 751B.

In the example of the pixel electrode shape shown in FIG. 12, three teeth form one group, but the number of teeth forming a group may be a number other than three, and there may be groups with different numbers of teeth in one tooth row. The pixel electrode shape shown in FIG. 12 can be applied to the pixel electrode layout shown in FIG. 4A.

Figure 13 shows another example of pixel electrode layout. In the above layout example, one pixel electrode partially overlaps with two pixel electrodes on both sides. In the layout example shown in Figure 13, one pixel electrode partially overlaps with two pixel electrodes on each side. The type of liquid crystal panel is FFS type.

Figure 13 shows the layout of pixel electrodes 801A to 801H. Each of pixel electrodes 801A to 801H has a double-tooth comb shape. Pixel electrodes 801A, 801B, and 801C are included in one pixel electrode row extending along the X-axis. Pixel electrodes 801D and 801E are included in one pixel electrode row extending along the X-axis. Pixel electrodes 801F, 801G, and 801H are included in one pixel electrode row extending along the X-axis. Pixel electrodes 801A to 801H are arranged in a staggered manner. Between adjacent pixel electrode rows, the positions of the pixel electrodes are shifted by half a pixel (half a pitch) along the X-axis.

In the configuration example shown in FIG. 13, a pixel electrode column aligned along the Y axis is composed of pixel electrodes with two different X coordinates that are alternately arranged. For example, pixel electrodes 801A, 801D, and 801F are continuous pixel electrodes in one pixel electrode column, and pixel electrodes 801B, 801E, and 801G are continuous pixel electrodes in another pixel electrode column.

The boundaries of the pixel regions are indicated by thick solid lines, and pixel regions 811A to 811H are pixel regions corresponding to pixel electrodes 801A to 801H, respectively. Each pixel region includes five pixel electrodes (portions of them). For example, pixel region 811D includes portions of pixel electrodes 801A, 801B, 801D, 801F, and 801G, and pixel region 811E includes portions of pixel electrodes 801B, 801C, 801E, 801G, and 801H. Although omitted in FIG. 13, the gate lines extend along the X-axis, and the data lines extend along the Y-axis.

In the layout of FIG. 13, a pixel electrode partially overlaps with four adjacent pixel electrodes along the Y axis. Two of the four adjacent pixel electrodes are included in one adjacent pixel electrode row, and the other two are included in the other adjacent pixel electrode row. The X and Y coordinates of the center of gravity of the pixel electrode are different from the X and Y coordinates of the center of gravity of each of these four adjacent pixel electrodes.

For example, pixel electrode 801D partially overlaps pixel electrodes 801A, 801B, 801F, and 801G. The X and Y coordinates of the center of gravity of pixel electrode 801D are different from the X and Y coordinates of the centers of gravity of pixel electrodes 801A, 801B, 801F, and 801G. The Y coordinates of the centers of gravity of pixel electrodes 801A and 801B are the same, but the X coordinates are different. The X coordinates of the centers of gravity of pixel electrodes 801A and 801F are the same, but the Y coordinates are different. The X coordinates of the centers of gravity of pixel electrodes 801B and 801G are the same, but the Y coordinates are different. The Y coordinates of the centers of gravity of pixel electrodes 801F and 801G are the same, but the X coordinates are different.

For example, pixel electrode 801E partially overlaps with pixel electrodes 801B, 801C, 801G, and 801H. The X and Y coordinates of the center of gravity of pixel electrode 801E are different from the X and Y coordinates of the centers of gravity of pixel electrodes 801B, 801C, 801G, and 801H. The Y coordinates of the centers of gravity of pixel electrodes 801B and 801C are the same, but the X coordinates are different. The X coordinates of the centers of gravity of pixel electrodes 801C and 801H are the same, but the Y coordinates are different. The Y coordinates of the centers of gravity of pixel electrodes 801G and 801H are the same, but the X coordinates are different.

The driving circuit 138, for example, applies a signal potential of the same polarity to all pixel electrodes relative to a common potential. The driving circuit 138 inverts the polarity of the signal potential applied to each electrode for each frame. The layout shown in FIG. 13 makes it possible to configure pairs of pixel electrodes that partially overlap and have different X and Y coordinates, and to obtain intermediate tones between adjacent pixels in both the X-axis direction and the Y-axis direction without image processing.

Figure 14 shows an example in which both the IPS type and FFS type driving types are used in the pixel electrode layout shown in Figure 13. The shape and layout of the pixel electrodes shown in Figure 14 are similar to the example shown in Figure 13. The layout of the common electrode (not shown) differs between the configuration examples of Figures 13 and 14.

As shown in FIG. 14, the single region in the center of the pixel operates in the FFS type. Specifically, an electric field is generated between the pixel electrode and a common electrode (not shown) that is arranged on a different layer (e.g., a lower layer) from the pixel electrode. In an FFS type liquid crystal panel, the two electrodes that make up the electrode pair that applies an electric field to the liquid crystal are formed on different layers (on different insulating films).

On the other hand, the overlap region operates as an IPS type. Specifically, there is no common electrode in the overlap region, and an electric field is generated between the different pixel electrodes contained in the overlap region to apply a voltage to the liquid crystal. In an IPS type liquid crystal panel, the two electrodes that make up the electrode pair that applies an electric field to the liquid crystal are formed in the same layer (on the same insulating film).

When the polarities of the signal potentials of adjacent pixel electrodes are different, the single region in the center of the pixel operates as an FFS type and is driven by a low voltage between the pixel electrode and the common electrode. On the other hand, the overlapping region operates as an IPS type and is driven by the signal potential difference in the adjacent pixel electrodes. The potential difference between adjacent pixel electrodes is greater than the potential difference between the pixel electrode and the common electrode.

When using liquid crystal with the same Δε, the drive voltage for the IPS type tends to be higher than that for the FFS type. Therefore, the overlap region of the IPS type requires a higher drive voltage than the single region of the FFS type, but by applying signal potentials of opposite polarity to adjacent pixel electrodes that partially overlap, the overlap region of the IPS type can be driven at the maximum voltage.

In the staggered arrangement example shown in Figures 13 and 14, the positions of the pixel electrodes between adjacent pixel electrode rows are shifted by half a pixel (half a pitch) along the X-axis (gate line). In another staggered arrangement example, the positions of the pixel electrodes between adjacent pixel electrode columns may be shifted by half a pixel (half a pitch) along the Y-axis (data line). In this example, the pixel electrodes are spaced apart from the pixel electrodes adjacent to them on either side along the data line, and partially overlap with the four pixel electrodes adjacent to them along the gate line.

The above configuration example can perform blurring processing without increasing the number of data lines in order to increase the resolution of the monochrome liquid crystal panel, and can avoid a decrease in the transmittance of the monochrome liquid crystal panel. It can also reduce the load of the control device 110 on the image diffusion processing of the monochrome liquid crystal panel. This configuration also eliminates the need for a black matrix that is provided to prevent light leakage between adjacent pixels, making it possible to increase the aperture ratio (transmittance).

Figure 15 shows another example of pixel electrode shape. Below, differences from the configuration example shown in Figure 11 will be mainly explained. The arrangement of the teeth of pixel electrode 821A is different from the arrangement of the teeth of pixel electrode 701A, but the other parts are similar. The arrangement of the teeth of pixel electrode 821B is different from the arrangement of the teeth of pixel electrode 701B, but the other parts are similar. The arrangement of the teeth of pixel electrode 821C is different from the arrangement of the teeth of pixel electrode 701C, but the other parts are similar.

In FIG. 15, one of the short teeth of pixel electrode 821A is indicated by reference symbol 822A as an example, and one of the long teeth is indicated by reference symbol 823A as an example. One of the short teeth of pixel electrode 821B is indicated by reference symbol 822B as an example, and one of the long teeth is indicated by reference symbol 823B as an example. One of the short teeth of pixel electrode 821C is indicated by reference symbol 822C as an example, and one of the long teeth is indicated by reference symbol 823C as an example. Pixel electrodes 821A and 821C have the same shape.

The tooth row of pixel electrode 821A is composed of two groups of four consecutive short teeth 822A and a group of eight consecutive long teeth 823A sandwiched between them. The tooth row of pixel electrode 821B is composed of two groups of four consecutive long teeth 823B and a group of eight consecutive short teeth 822B sandwiched between them. The tooth row of pixel electrode 821C is composed of two groups of four consecutive short teeth 822C and a group of eight consecutive long teeth 823C sandwiched between them.

In the overlapping region 761, two groups consisting of each of the four long teeth 823B of pixel electrode 821B and a group consisting of each of the eight short teeth 823A of pixel electrode 821A sandwiched between the two groups are arranged. In the overlapping region 763, two groups consisting of each of the four long teeth 823B of pixel electrode 821B and a group consisting of each of the eight short teeth 823C of pixel electrode 821C sandwiched between the two groups are arranged.

In overlapping regions 761 and 763 of the configuration example of FIG. 15, multiple teeth of one of two adjacent pixel electrodes are sandwiched between a group of multiple teeth of the other pixel electrode. In the configuration example shown in FIG. 15, the areas of the two pixel electrodes in overlapping regions 761 and 763 are the same. Specifically, in overlapping region 761, the number of teeth and the area of each tooth of pixel electrode 821A are the same as the number of teeth and the area of each tooth of pixel electrode 821B. Similarly, in overlapping region 763, the number of teeth and the area of each tooth of pixel electrode 821C are the same as the number of teeth and the area of each tooth of pixel electrode 821B.

In the example of the pixel electrode shape shown in FIG. 15, four or eight teeth form one group, but the number of teeth forming a group may be a number other than four or eight, and there may be groups with different numbers of teeth in one tooth row. The pixel electrode shape shown in FIG. 15 can be applied to the pixel electrode layout shown in FIG. 4A.

Figure 16 shows another example of pixel electrode shape. Below, differences from the configuration example shown in Figure 11 will be mainly explained. The arrangement of the teeth of pixel electrode 831A is different from the arrangement of the teeth of pixel electrode 701A, but the other parts are similar. The arrangement of the teeth of pixel electrode 831B is different from the arrangement of the teeth of pixel electrode 701B, but the other parts are similar. The arrangement of the teeth of pixel electrode 821C is different from the arrangement of the teeth of pixel electrode 701C, but the other parts are similar. Pixel electrodes 701A to 701C have symmetrical shapes about the ridges, but pixel electrodes 831A to 831C have asymmetrical shapes about the ridges.

In FIG. 16, one of the short teeth of pixel electrode 831A is indicated by reference numeral 832A as an example, and one of the long teeth is indicated by reference numeral 833A as an example. One of the short teeth of pixel electrode 821B is indicated by reference numeral 832B as an example, and one of the long teeth is indicated by reference numeral 833B as an example. One of the short teeth of pixel electrode 831C is indicated by reference numeral 832C as an example, and one of the long teeth is indicated by reference numeral 833C as an example. Pixel electrodes 831A, 831B, and 831C have the same shape.

The tooth row on one side of pixel electrode 831A is composed of two groups of four consecutive long teeth 833A and a group of eight consecutive short teeth 832A sandwiched between them. The tooth row on the other side of pixel electrode 831A is composed of two groups of four consecutive short teeth 832A and a group of eight consecutive long teeth 833A sandwiched between them. In the example shown in FIG. 16, the short teeth 832A and the long teeth 833A are arranged on one side and the other side at the same position on the ridge. The tooth rows of pixel electrodes 831B and 831C have a structure similar to that of pixel electrode 831A.

In the overlapping region 761, two groups consisting of each of the four long teeth 833B of pixel electrode 831B and a group consisting of each of the four short teeth 832A of pixel electrode 831A sandwiched between the two groups are arranged. In the overlapping region 763, two groups consisting of each of the four long teeth 833C of pixel electrode 831C and a group consisting of each of the four short teeth 832B of pixel electrode 831B sandwiched between the two groups are arranged.

In overlapping regions 761 and 763 of the configuration example of FIG. 16, multiple teeth of one of two adjacent pixel electrodes are sandwiched between a group of multiple teeth of the other pixel electrode. In the configuration example shown in FIG. 16, the areas of the two pixel electrodes in overlapping regions 761 and 763 are the same. Specifically, in overlapping region 761, the number of teeth and the area of each tooth of pixel electrode 831A are the same as the number of teeth and the area of each tooth of pixel electrode 831B. Similarly, in overlapping region 763, the number of teeth and the area of each tooth of pixel electrode 831C are the same as the number of teeth and the area of each tooth of pixel electrode 831B.

In the example of the pixel electrode shape shown in FIG. 16, four or eight teeth make up one group, but the number of teeth making up a group may be different from these, and there may be groups with different numbers of teeth in one tooth row. The pixel electrode shape shown in FIG. 16 can be applied to the pixel electrode layout shown in FIG. 4A.

Figure 17 shows another example of pixel electrode shape. Below, differences from the configuration example shown in Figure 11 will be mainly explained. The arrangement of the teeth of pixel electrode 851A is different from the arrangement of the teeth of pixel electrode 701A, but the other parts are similar. The arrangement of the teeth of pixel electrode 851B is different from the arrangement of the teeth of pixel electrode 701B, but the other parts are similar. The arrangement of the teeth of pixel electrode 851C is different from the arrangement of the teeth of pixel electrode 701C, but the other parts are similar.

In FIG. 17, one tooth of each of pixel electrodes 851A, 851B, and 851C is indicated by the reference numerals 852A, 852B, and 852C as an example.

The pixel electrode 851A has a shape with two-fold symmetry. Specifically, the teeth of the pixel electrode 851A have a diamond shape, and the length of the teeth 852A gradually decreases from the center of the ridge line toward the edge. In the example shown in FIG. 17, the pixel electrode 851A has 16 teeth 852A on each side. The pixel electrode 851C has the same shape as the pixel electrode 851A.

The pixel electrode 851B has a shape that is two-fold symmetric. Specifically, the teeth of the pixel electrode 851B have an hourglass shape that is narrowed in the middle. The length of the teeth 852B gradually increases from the center of the ridge toward the edge. In the example shown in FIG. 17, the pixel electrode 851B has 16 teeth 852B on each side.

The configuration example shown in FIG. 17 has wider overlapping areas 761 and 763 and a narrow single area 762 compared to the configuration example shown in FIG. 11. Therefore, a more natural display can be achieved by performing a luminance smoothing process. In the overlapping areas 761 and 763, the areas of the two pixel electrodes are the same. Specifically, in the overlapping area 761, the total area of the teeth of the pixel electrode 851A is the same as the total area of the teeth of the pixel electrode 851B. Similarly, in the overlapping area 763, the total area of the teeth of the pixel electrode 851C is the same as the total area of the teeth of the pixel electrode 851B. The pixel electrode having the shape shown in FIG. 17 can be applied to the pixel electrode layout shown in FIG. 4A.

Figure 18 shows another example of pixel electrode shape. Below, differences from the configuration example shown in Figure 11 will be mainly explained. The arrangement of the teeth of pixel electrode 861A is different from the arrangement of the teeth of pixel electrode 701A, but the other parts are similar. The arrangement of the teeth of pixel electrode 861B is different from the arrangement of the teeth of pixel electrode 701B, but the other parts are similar. The arrangement of the teeth of pixel electrode 861C is different from the arrangement of the teeth of pixel electrode 701C, but the other parts are similar.

In FIG. 18, one tooth of each of pixel electrodes 861A, 861B, and 861C is indicated by the reference numerals 862A, 862B, and 862C as an example.

The pixel electrode 861A has a shape that is line-symmetrical with respect to a virtual line that passes through the center of the ridge and is perpendicular to the ridge. Specifically, the group of teeth on one side of the pixel electrode 861A has an M-shape with a narrowed center, and the length of the teeth 862A gradually increases from the center of the ridge to the edge. The group of teeth on the other side of the pixel electrode 861A has a wedge shape, and the length of the teeth 862A gradually decreases from the center of the ridge to the edge. The shape of the group of teeth on one side and the shape of the group of teeth on the other side are complementary so that they fit together. In the example shown in FIG. 18, the pixel electrode 861A has 16 teeth 852A on each side. The pixel electrodes 861B and 861C have the same shape as the pixel electrode 861A.

The configuration example shown in FIG. 18 has wide overlapping areas 761, 763 and a narrow single area 762, similar to the configuration example shown in FIG. 17. Therefore, by performing a luminance smoothing process, a more natural display can be achieved. In the overlapping areas 761 and 763, the areas of the two pixel electrodes are the same. Specifically, in the overlapping area 761, the total area of the teeth of pixel electrode 861A is the same as the total area of the teeth of pixel electrode 861B. Similarly, in the overlapping area 763, the total area of the teeth of pixel electrode 861C is the same as the total area of the teeth of pixel electrode 861B. The pixel electrodes of the shape shown in FIG. 18 can be applied to the pixel electrode layout shown in FIG. 4A.

The above configuration example is a horizontal electric field control type liquid crystal panel, but the features of the present disclosure can also be applied to TN type and VA type liquid crystal panels. As in the above example, the pixel electrodes are formed and arranged so that adjacent pixel electrodes partially overlap. The gate lines and data lines may be straight or curved as described with reference to the figures.

Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments. A person skilled in the art can easily modify, add, or convert each element of the above embodiments within the scope of the present disclosure. It is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment.

131 color liquid crystal panel, 132 monochrome liquid crystal panel, 133 surface light source, 137, 138 driving circuit, 141, 142 pixel, 302A-302D data line, 400A-400D pixel area, 401A, 401B pixel electrode, 402A-402D data line, 404A, 404B gate line, 406A-406E pixel electrode, 450, 452, 454 single area, 451, 453, 455 overlap area, 501, 551 ridge portion, 503A, 503B, 521, 553A, 555A, 555B, 571 teeth, 601A, 601B pixel electrode, 602A, 602B, 604A, 604B data line, 605 Overlap area, 651 insulating substrate, 652 insulating film, 653 semiconductor film, 654 interconnection portion, 655 insulating film, 656 interlayer insulating film, 657 common electrode, 658 insulating film, 659 via, 701A-701C pixel electrode, 702A data line, 704A gate line, 711, 713 overlap area, 712 single area, 751A-751C pixel electrode, 761, 763 overlap area, 801A-801H pixel electrode, 811A-811H pixel area, 821A-821C pixel electrode, 822A-822C teeth, 823A-823C teeth, 831A-831C pixel electrode, 832A-832C teeth, 833A-833C Teeth, 851A-851C Pixel electrode, 852A-852C Teeth, 861A-861C Pixel electrode, 862A-862C Teeth

Claims (11)

A light source device for a display device, comprising:
A surface light source;
A monochrome LCD panel
Including,
The monochrome liquid crystal panel includes a plurality of pixel electrodes,
Among the plurality of pixel electrodes, adjacent pixel electrodes partially overlap each other within one pixel,
the monochrome liquid crystal panel includes a single region including a portion of one pixel electrode among the plurality of pixel electrodes and not including other pixel electrodes, and an overlap region including portions of adjacent pixel electrodes ,
the adjacent pixel electrodes are composed of a first pixel electrode and a second pixel electrode,
each of the first pixel electrode and the second pixel electrode includes a ridge portion and a tooth row on both sides of the ridge portion;
the teeth of the first pixel electrode and the teeth of the second pixel electrode partially overlap each other,
the ridge portion is disposed between adjacent gate lines and between adjacent data lines in a plan view;
Light source device. A light source device for a display device, comprising:
A surface light source;
A monochrome LCD panel
Including,
The monochrome liquid crystal panel includes a plurality of pixel electrodes,
Among the plurality of pixel electrodes, adjacent pixel electrodes partially overlap each other within one pixel,
the monochrome liquid crystal panel includes a single region including a portion of one pixel electrode among the plurality of pixel electrodes and not including other pixel electrodes, and an overlap region including portions of adjacent pixel electrodes,
the adjacent pixel electrodes are composed of a first pixel electrode and a second pixel electrode,
each of the first pixel electrode and the second pixel electrode includes a ridge portion and a tooth row on both sides of the ridge portion;
the teeth of the first pixel electrode and the teeth of the second pixel electrode partially overlap each other,
the ridge portion extends in the same direction as one of the gate line and the data line and overlaps with the gate line and the data line in a plan view;
Light source device. 3. The light source device according to claim 1,
The monochrome liquid crystal panel includes a plurality of pixel electrode lines, each of which is made up of pixel electrodes arranged along a first axis;
The pixel electrode lines are arranged in a direction along a second axis perpendicular to the first axis,
In each pixel electrode line of the plurality of pixel electrode lines, the single region and the overlap region are alternately arranged.
Light source device. The light source device according to claim 1 ,
The monochrome liquid crystal panel includes a plurality of pixel electrode lines, each of which is made up of pixel electrodes arranged along a first axis;
The pixel electrode lines are arranged in a direction along a second axis perpendicular to the first axis,
In each pixel electrode line of the plurality of pixel electrode lines, the single region and the overlap region are alternately arranged;
one of the gate line and the data line extends along the first axis and is arranged along the second axis;
the other of the gate line and the data line extends along the second axis and is arranged along the first axis;
Light source device. The light source device according to claim 2 ,
The monochrome liquid crystal panel includes a plurality of pixel electrode lines, each of which is made up of pixel electrodes arranged along a first axis;
The pixel electrode lines are arranged in a direction along a second axis perpendicular to the first axis,
In each pixel electrode line of the plurality of pixel electrode lines, the single region and the overlap region are alternately arranged;
the one of the gate lines and the data lines extends along the second axis and is aligned along the first axis;
Light source device. 3. The light source device according to claim 1 ,
In the overlapping region, the teeth of the first pixel electrode and the teeth of the second pixel electrode are alternately arranged.
Light source device. 3. The light source device according to claim 1 ,
In the overlapping region, a first group consisting of a plurality of consecutive teeth of the first pixel electrode and a second group consisting of a plurality of consecutive teeth of the second pixel electrode are alternately arranged.
Light source device. 3. The light source device according to claim 1,
Each pixel electrode of the plurality of pixel electrodes partially overlaps two adjacent pixel electrodes on one side and partially overlaps two adjacent pixel electrodes on the other side.
Light source device. The light source device according to claim 8,
In the single region, the pixel electrode and a common electrode formed in a different layer on the same substrate as the pixel electrode form an electric field to be applied to liquid crystal;
In the overlapping region, the adjacent pixel electrodes form an electric field to be applied to the liquid crystal.
Light source device. A color LCD panel,
A monochrome LCD panel
A surface light source;
the color liquid crystal panel, the monochrome liquid crystal panel, and the surface light source are stacked;
The monochrome liquid crystal panel includes a plurality of pixel electrodes,
Among the plurality of pixel electrodes, adjacent pixel electrodes partially overlap each other within one pixel,
the monochrome liquid crystal panel includes a single region including a portion of one pixel electrode among the plurality of pixel electrodes and not including other pixel electrodes, and an overlap region including portions of adjacent pixel electrodes ,
the adjacent pixel electrodes are composed of a first pixel electrode and a second pixel electrode,
each of the first pixel electrode and the second pixel electrode includes a ridge portion and a tooth row on both sides of the ridge portion;
the teeth of the first pixel electrode and the teeth of the second pixel electrode partially overlap each other,
the ridge portion is disposed between adjacent gate lines and between adjacent data lines in a plan view;
Liquid crystal display device. A color LCD panel,
A monochrome LCD panel
A surface light source;
the color liquid crystal panel, the monochrome liquid crystal panel, and the surface light source are stacked;
The monochrome liquid crystal panel includes a plurality of pixel electrodes,
Among the plurality of pixel electrodes, adjacent pixel electrodes partially overlap each other within one pixel,
the monochrome liquid crystal panel includes a single region including a portion of one pixel electrode among the plurality of pixel electrodes and not including other pixel electrodes, and an overlap region including portions of adjacent pixel electrodes,
the adjacent pixel electrodes are composed of a first pixel electrode and a second pixel electrode,
each of the first pixel electrode and the second pixel electrode includes a ridge portion and a tooth row on both sides of the ridge portion;
the teeth of the first pixel electrode and the teeth of the second pixel electrode partially overlap each other,
the ridge portion extends in the same direction as one of the gate line and the data line and overlaps with the gate line and the data line in a plan view;
Liquid crystal display device.

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