The present application claims priority from Japanese application JP2014-124933 filed on Jun. 18, 2014, the content of which is hereby incorporated by reference into this application.
The present invention relates to a liquid crystal display device.
Liquid crystal display devices have been widely used as display devices of information communication terminals such as computers, or television receivers. The liquid crystal display device is a device to display an image by changing the alignment of a liquid crystal composition sealed between two substrates with a change in electric field, and controlling the degree of transmission of light passing through the two substrates and the liquid crystal composition.
In order to change the electric field, a voltage corresponding to the gray-scale value of each of pixels is applied to a pixel electrode via a pixel transistor of each of the pixels.
In a so-called in-plane switching (IPS) type liquid crystal display device in which the pixel electrode and a counter electrode that forms the electric field in combination with the pixel electrode are formed in the same thin film transistor (TFT) substrate, white display is changed into blue one or yellow one depending on viewing angle directions, and thus image quality is reduced in some cases.
It has been known for solving this image quality reduction to use a dual-domain structure in which two areas (domains) where electrodes extend in different directions are formed in each of the pixels to vary the alignment state of the liquid crystal composition, and thus the changes in color are canceled out each other. Japanese Patent No. 4414824 discloses a liquid crystal display device in which a pixel is divided into four domains to thereby improve viewing angle characteristics.
In the dual-domain structure described above, since the liquid crystal composition is not operated at a portion at which the direction of the electrode changes and the portion is not used as the effective area of the pixel, there is a risk of a reduction in transmittance.
The invention has been made in view of the circumstances described above, and it is an object of the invention to provide an IPS type liquid crystal display device with improved transmittance.
Representative liquid crystal display devices for solving the problem are as follows.
(1) A liquid crystal display device comprising a display area having a plurality of pixels disposed in a matrix with rows and columns, the display area including a first configuration column and a second configuration column, the first configuration column being a column having a plurality of first pixels aligned therein, the plurality of first pixels each including a pixel electrode including a first area and a second area, the first area having a plurality of electrodes disposed therein, the plurality of electrodes extending in a first direction inclined to the column direction, the second area having a plurality of electrodes disposed therein, the plurality of electrodes extending in a second direction inclined differently from the first direction, the second configuration column being a column having a plurality of second pixels and a plurality of third pixels alternately aligned therein, the plurality of second pixels each including a pixel electrode including a plurality of electrodes extending in a third direction inclined to the column direction, the plurality of third pixels each including a pixel electrode including a plurality of electrodes extending in a fourth direction inclined differently from the third direction.
(2) In the liquid crystal display device according to (1), the width of each of the second pixel and the third pixel in the row-direction is larger than the width of the first pixel in the row-direction.
(3) In the liquid crystal display device according to (1) or (2), the display area includes a first column located in the first configuration column and including some first pixels that emit light in a red wavelength range, a second column located in the first configuration column and including some first pixels that emit light in a green wavelength range, and a third column located in the second configuration column and including some second pixels that emit light in one of blue and white wavelength ranges and some third pixels that emit light in the other of the blue and white wavelength ranges.
(4) In the liquid crystal display device according to any one of (1) to (3), one first pixel in which the first area and the second area are aligned in this order in the column direction and one first pixel in which the second area and the first area are aligned in this order in the column direction are alternately disposed in the first configuration column, two first areas are adjacent to each other in two first pixels aligned adjacent to each other in the column direction, two second areas are adjacent to each other in other two first pixels aligned adjacent to each other in the column direction, the second pixel is disposed adjacent in the row direction to an area between the two first areas aligned adjacent to each other in the column direction, and the third pixel is disposed adjacent in the row direction to an area between the two second areas aligned adjacent to each other in the column direction.
(5) In the liquid crystal display device according to (4), the third direction is the first direction, and the fourth direction is the second direction.
(6) In the liquid crystal display device according to (4) or (5), the liquid crystal display device further includes a scanning signal line connected to a gate of a pixel transistor whose source or drain is connected to the pixel electrode, and the scanning signal line is disposed to be bent so as to pass between the two first pixels aligned adjacent to each other in the column direction and between the second pixel and the third pixel.
(7) In the liquid crystal display device according to (4) or (5), the liquid crystal display device further includes a scanning signal line connected to a gate of a pixel transistor whose source or drain is connected to the pixel electrode, and the scanning signal line is disposed to extend so as to pass between two first pixels adjacent to each other, divide the second pixels, and divide the third pixels.
Hereinafter, embodiments of the invention will be described with reference to the drawings. The disclosure is illustrative only. Appropriate modifications that will readily occur to those skilled in the art and fall within the gist of the invention are of course included in the scope of the invention. In the drawings, the width, thickness, shape, and the like of each part may be schematically represented, compared to those in practicing aspects of the invention, for more clarity of description. However, they are illustrative only, and do not limit the interpretation of the invention. Moreover, in the specification and the drawings, elements similar to those described in relation to a previous drawing are denoted by the same reference numerals and signs, and a detailed description may be appropriately omitted.
The TFT substrate 120 is a substrate formed of transparent glass or a resin insulating material. A driver integrated circuit (IC) 180 as a semiconductor integrated circuit element is placed on the TFT substrate 120. The driver IC 180 applies, to a scanning signal line connected to gates of pixel transistors each of which is disposed in the pixel 200, a voltage for establishing electrical continuity between a source and a drain, and also applies, to a video signal line, a voltage corresponding to the gray-scale value of the pixel 200. Moreover, a flexible printed circuit (FPC) 191 for inputting an image signal or the like from the outside is attached to the TFT substrate 120. The liquid crystal display device used in the embodiment is a liquid crystal display device of a so-called IPS type (or a lateral electric field type) in which both pixel electrodes and a counter electrode (common electrode) are disposed in the TFT substrate 120 chosen from between the TFT substrate 120 and the counter substrate 150.
Each of the R sub-pixel 211 and the G sub-pixel 212 includes a first pixel 210 having the shape of an arrangement area of a dogleg-shaped pixel electrode that extends in two different directions inclined to the column direction. The shapes of arrangement areas of pixel electrodes of the B sub-pixel and the W sub-pixel show a second pixel 221 and a third pixel 222, respectively, having the shapes each of which extends in one direction inclined to the column direction. Here, a column in which the first pixels 210 are aligned is referred to as a first configuration column 216, while a column in which the second pixel 221 and the third pixel 222 are alternately aligned is referred to as a second configuration column 226.
In the embodiment, the width of each of the second pixel 221 and the third pixel 222, in the row direction, that constitute the second configuration column 226 is formed to be larger than the width of the first pixel 210 in the row direction, and an opening of each of the second pixel 221 and the third pixel 222 is made larger, so that the area of each of the second pixel 221 and the third pixel 222 each of which includes pixels whose number is about half of that of the R sub-pixel 211 or the G sub-pixel 212 is compensated. In the invention, however, the width of each of the second pixel 221 and the third pixel 222 in the row direction may be the same or smaller than the width of the R sub-pixel 211 or the G sub-pixel 212 in the row direction.
As described above, the second pixel electrode 240 and the third pixel electrode 250 are directed in different directions inclined to the column direction, and with the second and third pixel electrodes acting as a dual-domain pixel electrode together, a reduction in image quality according to viewing angles is suppressed. Moreover, since the second pixel electrode 240 and the third pixel electrode 250 are not provided with the bent portion 233 compared to the first pixel electrode 230, it is possible in the second pixel 221 and the third pixel 222 to suppress a reduction in transmittance due to non-alignment of a liquid crystal composition at the bent portion 233 and improve the transmittance compared to that in the presence of the bent portion 233.
In
Although the second pixel 221 and the third pixel 222 are sub-pixels that emit different color lights in the embodiment described above, the second pixel and the third pixel may be sub-pixels that emit the same color light. Moreover, although the embodiment described above is configured to include two first configuration columns 216 and one second configuration column 226, it is sufficient that the combination of the first configuration column and the second configuration column includes at least one first configuration column and at least one second configuration column such as, for example, a configuration composed of one first configuration column 216 and one second configuration column 226, and the combination can be appropriately changed. Moreover, although the embodiment described above includes the sub-pixels that emit four R, G, B, and W color (wavelength range) lights, the invention can be applied to a liquid crystal display device including sub-pixels that emit three R, G, and B color lights or two or more color lights.
Hence, according to the embodiment described above as shown in
Here, the third direction 249 of the second pixel electrode 240 is set to the first direction 238 of the first pixel electrode 230, and the fourth direction 259 of the third pixel electrode 250 is set to the second direction 239 of the first pixel electrode 230, that is, the first direction 238 and the third direction 249 are substantially the same direction, and the second direction 239 and the fourth direction 259 are substantially the same direction, whereby the display area 205 can be filled with the pixel electrodes without making gaps. With this configuration, the overall transmittance in the display area 205 can be improved, and also, the power consumption can be suppressed.
In
While there have been described what are at present considered to be certain embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention.
Number | Date | Country | Kind |
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2014-124933 | Jun 2014 | JP | national |
Number | Date | Country | |
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Parent | 15787765 | Oct 2017 | US |
Child | 16261785 | US | |
Parent | 14743554 | Jun 2015 | US |
Child | 15787765 | US |