JP2006251322A - Liquid crystal display device and electronic information apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure a sufficient aperture ratio even in a high-definition liquid crystal panel whose pixel size is small. <P>SOLUTION: An RGB picture element portion is uses as one pixel portion and a display region is composed of three kinds of picture element shapes; and a 1st TFT 25a is connected between a 1st picture element electrode 24a and a signal line 21, a 2nd TFT 25b is connected between a 2nd picture element electrode 24b and the signal line 21, and a 3rd TFT 25c and a 4th TFT 25d are connected in series between a 3rd picture element electrode 24c and the signal line 21. Then 1/3 of picture element portions constituting a display screen are each equipped with two switching elements, and the display region is constituted on a liquid crystal display panel of A pixels×B pixels with wiring lines of A signal lines and B×2 scanning lines. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a small-sized and high-definition liquid crystal display device having a relatively small picture element size, and to an electronic information device such as a digital camera, a video camera, and a mobile phone device using the liquid crystal display device as a display unit.

  A conventional liquid crystal display device has a liquid crystal panel in which a liquid crystal layer is sandwiched between a pair of substrates, a pixel electrode formed on one TFT substrate, and a counter electrode formed on the other counter substrate. By applying a display voltage between them, the optical characteristics of the liquid crystal part (picture element) sandwiched between the two electrodes are modulated, and characters, figures, etc. are displayed on the display screen.

  FIG. 10 is a plan view of a main part for explaining a picture element shape in a conventional liquid crystal display device, FIG. 11 is a cross-sectional view taken along line AA ′ of FIG. 10, and FIG. 12 is a liquid crystal display device of FIG. 2 is an equivalent circuit diagram of one pixel portion in FIG.

  In FIG. 10, in the TFT substrate constituting the liquid crystal panel of the conventional liquid crystal display device 10, a plurality of signal lines (source bus lines) 1 and a plurality of scanning lines (gate bus lines) 2 cross each other on an insulating substrate. Furthermore, a Cs (auxiliary capacitor) bus line 3 is provided in parallel with each gate bus line 2 as necessary.

  For each picture element region surrounded by the source bus line 1 and the gate bus line 2, a picture element electrode 4 and a TFT 5 as a switching element for selectively driving the picture element electrode 4 are provided.

  As shown in FIG. 11, the TFT substrate is provided with a gate insulating film 12 on an insulating substrate 11, on which a pixel electrode 4 and a source bus line 1 are provided to cover the source bus line 1. Thus, a protective film 13 is provided.

  In the counter substrate, for example, an RGB colored layer 15 is provided on an insulating substrate 14, and a BM (black matrix) 16 is provided thereon.

  The TFT substrate and the counter substrate are arranged to face each other with a predetermined interval, and a liquid crystal layer 17 is sealed in a gap between the two substrates.

  As shown in FIG. 12, the pixel electrode 4 has, for example, three pixel electrodes 4a, 4b and 4c corresponding to three colors of RGB as one pixel portion (RGB 3 dots (picture element) = 1 pixel). They are arranged in a matrix. For example, in a liquid crystal panel of A pixel × B pixel, three source bus lines and one gate bus line are provided as one set, and A × 3 source bus lines and B gate bus lines are provided.

  In the first picture element portion (picture element 1), the gate of the first TFT 5a is connected to the gate bus line 2, its source is connected to the first source bus line 1a, and its drain is connected to the picture element electrode 4a. . Further, a liquid crystal capacitor Clc is formed between the pixel electrode 4a and the counter electrode, and an auxiliary capacitor Ccs is formed in parallel with the Cs bus line 3 and the pixel electrode 4a.

  In the second picture element portion (picture element 2), the gate of the second TFT 5b is connected to the gate bus line 2, its source is connected to the second source bus line 1b, and its drain is connected to the picture element electrode 4b. . A liquid crystal capacitor Clc is formed between the pixel electrode 4b and the counter electrode, and an auxiliary capacitor Ccs is formed in parallel with the Cs bus line 3 and the pixel electrode 4b.

  In the third picture element portion (picture element 3), the gate of the third TFT 5c is connected to the gate bus line 2, its source is connected to the third source bus line 1c, and its drain is connected to the picture element electrode 4c. . A liquid crystal capacitor Clc is formed between the pixel electrode 4c and the counter electrode, and an auxiliary capacitor Ccs is formed in parallel with the Cs bus line 3 and the pixel electrode 4c.

  FIG. 13 is a signal waveform diagram for explaining the operation of the conventional liquid crystal display device.

  As shown in FIG. 13, the first picture element portion is simultaneously applied to the first source bus line 1a while a high level voltage (ON voltage) for turning on the TFT 5 is applied to the gate bus line 2. The video signal voltage a applied to the second source bus line 1b is written to the second picture element portion, and the third source bus line 1c is written to the third picture element portion. The applied video signal voltage c is written.

  In recent years, in conventional liquid crystal display devices, high definition and high aperture ratio of liquid crystal panels are desired. However, in a small liquid crystal panel mounted on a mobile device such as a digital camera, a video camera, or a mobile phone device, the size of one dot (picture element) becomes small, and a sufficient aperture ratio cannot be secured. There is.

  In the conventional liquid crystal display device, for example, as shown in FIG. 14A, a VGA (640 pixels × 480 pixels) liquid crystal panel having a display screen diagonal size of 1.9 inches is considered as an example. 640 × 3 = 1920 and 480 gate bus lines 2 intersect in a matrix, and a switching element such as TFT 5 is arranged in the vicinity of each intersection. In this case, as shown in FIG. 14B, the size of one dot is 20 μm × 60 μm.

  Here, as shown in FIG. 10, for example, if the width of the source bus line 1 is 4 μm, the gap between the source and the pixel electrode 4 is 3 μm, and the bonding margin (distance between the pixel electrode 4 and BM) is 5 μm. BM opening = 0 μm, and the opening cannot be secured at all.

Therefore, for example, in Patent Document 1, the number of gate bus lines 2 is doubled, and the number of source bus lines 1 is halved (in the case of VGA, gate bus lines 2 = 960 lines and source bus lines 1 = 960 lines). A liquid crystal display device is disclosed in which a high aperture ratio is secured by connecting the source bus line 1 to each pixel electrode 4 provided on the left and right of the source bus line 1.
JP-A-11-352520

  As described above, in the conventional liquid crystal display device, since the A pixel × B pixel liquid crystal panel is provided with A × 3 source bus lines 1 and B gate bus lines 2, There is a problem that the size of one dot (picture element) is reduced, and it is difficult to secure a sufficient aperture ratio as described above.

  In Patent Document 1, in the liquid crystal panel of A pixel × B pixel, A × 2 source bus lines and B × 2 gate bus lines are provided, so that one dot (picture element) is provided as compared with a conventional liquid crystal display device. ) Can be made somewhat larger, but there is a problem that a small liquid crystal panel cannot be said to have a sufficient aperture ratio.

  The present invention solves the above-described conventional problems, and a liquid crystal display device capable of ensuring a sufficient aperture ratio even in a high-definition liquid crystal panel having a relatively small size of one picture element, and for example using the same An object of the present invention is to provide electronic information devices such as digital cameras, video cameras, and mobile phone devices.

  In the liquid crystal display device of the present invention, a plurality of signal lines and a plurality of scanning lines intersect with each other and are arranged in a matrix, and a picture element region provided at each intersection of the signal lines and the scanning lines has a picture. In a liquid crystal display device having an element electrode and a switching element selected by a scanning signal from the scanning line and capable of driving the pixel electrode by an image signal from the signal line, at least first and A second scanning line is provided, and at least first to third picture element electrodes are provided as the picture element electrodes for each picture element region, and the switching element is connected to the at least first to third pictures from the signal line. Each display voltage can be supplied to each element electrode, thereby achieving the above object.

  Preferably, in the liquid crystal display device of the present invention, first to fourth switching elements are provided as the switching elements in a pixel region provided at each intersection of the signal line and the scanning line, and the first The first switching element selected by the scanning signal of the first scanning line is connected between one pixel electrode and the signal line, and the second switching element is connected between the second pixel electrode and the signal line. The second switching element selected by the scanning signal of the scanning line is connected, and the third switching element selected by the scanning signal of the first scanning line is connected between the third pixel electrode and the signal line. The fourth switching element selected by the scanning signal of the second scanning line is provided in series connection.

  Further preferably, the display voltages are supplied in time division to the signal lines in the liquid crystal display device of the present invention.

  Further preferably, the first to third picture element electrodes in the liquid crystal display device of the present invention are arranged along the extending direction of the first scanning line and the second scanning line.

  More preferably, the first to third picture element electrodes in the liquid crystal display device of the present invention are arranged in a region surrounded by the signal lines and the scanning lines.

  Further preferably, the first to third picture element electrodes in the liquid crystal display device of the present invention are distributed in the extending direction by the signal lines.

  Further preferably, the first to third picture element electrodes in the liquid crystal display device of the present invention correspond to picture element portions of three kinds of colors.

  Further preferably, the three kinds of colors in the liquid crystal display device of the present invention are the three primary colors R, G and B.

  Further preferably, the first to third pixel electrodes in the liquid crystal display device of the present invention have the same or different pixel electrode shapes.

  Further preferably, in the liquid crystal display device of the present invention, a first period in which a driving voltage is applied only to the first scanning line, a second period in which a driving voltage is applied only to the second scanning line, A third period in which a drive voltage is applied to both the first scan line and the second scan line, the third period, the order of the first period and the second period, or the third period, A scan line driver circuit that repeats in the order of the second period and the first period is further included.

  Further, preferably, the length of the third period in the liquid crystal display device of the present invention is set longer than the other periods.

  Furthermore, it is preferable that the first to fourth switching elements in the liquid crystal display device of the present invention be transistors that can be charged to such a high degree that a difference in potential to reach the pixel electrode with respect to the potential of the signal line does not appear on the display.

  Furthermore, it is preferable that the third and fourth switching elements in the liquid crystal display device of the present invention be transistors that can be charged to such a high degree that a difference in potential to reach the pixel electrode with respect to the potential of the signal line does not appear on the display.

  Further preferably, in the liquid crystal display device of the present invention, the first to fourth switching elements are constituted by transistors, and are connected to the picture element electrodes at a wiring cross portion beyond one scanning line of the pair of scanning lines. The period during which the drive voltage is applied to the gate of each transistor is set longer than the period during which the drive voltage is applied to the other transistors.

  Still preferably, in the liquid crystal display device of the present invention, the first to fourth switching elements are each constituted by a transistor, and the wiring extends beyond at least one scanning line of the pair of scanning lines. The transistor connected to the pixel electrode at the cross portion is a transistor that can be charged to such a high degree that a difference in potential to reach the pixel electrode with respect to the potential of the signal line does not appear in the display.

  Further preferably, the width of the wiring cross portion in the liquid crystal display device of the present invention is set smaller than that of the wiring connected to the pixel electrode through the other transistor.

  Further preferably, in the liquid crystal display device of the present invention, at least one of the first scanning line and the second scanning line and the first to third pixel electrodes constitute an auxiliary capacitor via an insulating film.

  Further preferably, in the liquid crystal display device of the present invention, an auxiliary capacitance line is provided in parallel with the scanning line, and the first to third pixel electrodes and the auxiliary capacitance line have an auxiliary capacitance via an insulating film. It is composed.

  Further preferably, the size of each auxiliary capacitance for each pixel electrode between the first to third pixel electrodes and the scanning line and / or the auxiliary capacitance line in the liquid crystal display device of the present invention is the same or It is different.

  Furthermore, it is preferable that the switching element in the liquid crystal display device of the present invention is composed of four transistors, and the auxiliary element is arranged so that the potential fluctuations of the first to third pixel electrodes due to the voltage change of the gate signal are uniform. The capacitance is changed according to the size of the parasitic capacitance between the gate and the pixel electrode.

  Further, preferably, one or two branches from the signal line extending to the first, second and fourth switching elements are provided in the liquid crystal display device of the present invention.

  Further, preferably, the areas of the first to third pixel electrodes and the area of the opening in the liquid crystal display device of the present invention are the same or different.

  Further preferably, four or more picture element portions including the first to third picture element electrodes are provided as picture element electrodes in the liquid crystal display device of the present invention.

  In the electronic information device of the present invention, the liquid crystal display device of the present invention is used for a display portion, and thereby the above object is achieved.

  The operation of the present invention will be described below with the above configuration.

  In the present invention, for example, at least first to third picture element electrodes are provided as picture element electrodes for each picture element region of RGB picture elements = 1 pixel portion, and the switching elements are at least first to first from the signal lines. Each display voltage can be supplied to the third pixel electrode.

  For example, a first switching element is connected between the first picture element electrode and the signal line, a second switching element is connected between the second picture element electrode and the signal line, and the third picture element electrode and the signal line. The third switching element and the fourth switching element are connected in series.

  As described above, the display area is configured with the number of signal lines (source bus lines) = A and the number of scanning lines (gate bus lines) = B × 2 for the A pixel × B pixel liquid crystal display panel. . For example, in the case of VGA, the number of source bus lines = 640 and the number of gate bus lines = 960.

  The number of scanning lines is twice that of the conventional liquid crystal display device shown in FIG. 10, but the number of signal lines is 1/3 that of the conventional liquid crystal display device. Further, the number of scanning lines is the same as that of the conventional liquid crystal display device disclosed in Patent Document 1, and the number of signal lines can be reduced to 2/3 that of Patent Document 1. This makes it possible to fill the display area with the area occupied by the signal lines in the horizontal direction, without reducing the process margin such as the wiring width and the wiring interval, and without increasing the number of constituent films. Therefore, it is possible to secure a necessary opening and increase the aperture ratio. Furthermore, since the total number of signal lines and scanning lines is reduced, it is possible to improve the manufacturing yield including the driver IC and to reduce the frame.

  As described above, according to the present invention, the number of signal lines is greatly reduced as compared with the conventional liquid crystal display device, and the area in one direction (for example, the horizontal direction) occupied by the signal lines is used as the display area. As a result, it is possible to secure a necessary opening and increase the aperture ratio without reducing the process margin such as the wiring width and the wiring interval and without increasing the number of constituent films. Further, by reducing the total number of signal lines and scanning lines, it is possible to improve the manufacturing yield including the driver IC and to narrow the frame.

Embodiments 1 to 5 of the liquid crystal display device of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a main part plan view for explaining a picture element shape in a liquid crystal display device according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. FIG. 2 is an equivalent circuit diagram of one pixel portion in the liquid crystal display device of FIG. 1. In addition, the same code | symbol is attached | subjected to the member which show | plays the effect similar to FIGS.

  In FIG. 1, the TFT side substrate constituting the liquid crystal panel of the liquid crystal display device 20 of Embodiment 1 has a plurality of signal lines (source bus lines) 21 and a plurality of scanning lines (gate bus lines) 22 on an insulating substrate. Are crossed (orthogonal) with each other and arranged in a matrix, and a Cs (auxiliary capacitor) bus line line 3 is provided in parallel with the gate bus line 22 as necessary.

  In the picture element region surrounded by the source bus line 21 and the gate bus line 22, a picture element electrode 24 and a TFT 25 as a switching element for selectively driving the picture element electrode 24 are provided. In this way, the TFT substrate of the liquid crystal display device 20 of Embodiment 1 is configured.

  As shown in FIG. 2, in this TFT substrate, a gate insulating film 12 is provided on an insulating substrate 11, a pixel electrode 24 and a source bus line 21 are provided in this order on the gate insulating film 12. A protective film 26 is provided so as to cover the surface.

  As the counter substrate, for example, an RGB colored layer 15 is provided on an insulating substrate 14, and a BM (black matrix) 16 is provided thereon.

  The TFT substrate and the counter substrate are arranged to face each other with a predetermined interval, and a liquid crystal layer 17 is sealed in a gap between the two substrates.

  As shown in FIG. 3, the pixel electrode 4 has three pixel electrodes 24a, 24b and 24c corresponding to, for example, the three primary colors of RGB as one pixel portion (RGB 3 dots (picture element) = 1 pixel). The gate bus lines 22 (the first gate bus line 22a and the second gate bus line 22b) that are adjacent and parallel to each other are adjacent to each other along the extending direction (left-right direction) and are repeatedly arranged side by side. These picture element electrodes 24 a, 24 b and 24 c are arranged in a picture element region surrounded by the source bus line 21 and the gate bus line 22. In a liquid crystal panel of A pixel × B pixel, one source bus line 21 and two gate bus lines 22a and 22b are made into one set, the source bus line 21 is A, and the gate bus line 22 is B × 2. Is provided.

  In the first picture element portion (picture element 1), the gate of the first TFT 25a is connected to the first gate bus line 22a, its source is connected to the source bus line 21, and its drain is connected to the picture element electrode 24a. . Further, a liquid crystal capacitor Clc is formed between the pixel electrode 24a and the counter electrode, and an auxiliary capacitor Ccs is formed in parallel with the Cs bus line 3 and the pixel electrode 24a.

  In the second picture element section (picture element 2), the gate of the second TFT 25b is connected to the second gate bus line 22b, its source is connected to the source bus line 21, and its drain is connected to the picture element electrode 24b. . Further, a liquid crystal capacitor Clc is formed between the pixel electrode 24b and the counter electrode, and an auxiliary capacitor Ccs is formed in parallel with the Cs bus line 3 and the pixel electrode 24b.

  In the third picture element portion (picture element 3), the third TFT 25c and the fourth TFT 25d are connected in series, the gate of the third TFT 25c is connected to the first gate bus line 22a, and the gate of the fourth TFT 25d is connected to the second gate bus line 22b. The source of the fourth TFT 25d is connected to the source bus line 21, the drain of the fourth TFT 25d is connected to the source of the third TFT 25c, and the drain of the third TFT 25c is connected to the pixel electrode 24c. A liquid crystal capacitor Clc is formed by liquid crystal sandwiched between the pixel electrode 24c and the counter electrode, and is assisted by an insulating film provided in parallel between the Cs bus line 3 and the pixel electrode 24c. A capacitor Ccs is formed.

  In the liquid crystal display device 20 of the first embodiment, for example, as shown in FIG. 4A, a VGA (640 pixels × 480 pixels) liquid crystal panel having a display screen diagonal size of 1.9 inches is considered as an example. 640 lines 21 and 480 gate bus lines 22 × 2 = 960 intersect each other in a matrix, and switching elements such as TFTs 25 are arranged in the vicinity of these intersections. In this case, as shown in FIG. 4B, the size of one dot is 20 μm × 60 μm.

  Here, as shown in FIG. 1, for example, if the width of the source bus line 21 is 4 μm, the gap between the source and the pixel electrode 24 is 3 μm, and the bonding margin (distance between the pixel electrode 24 and BM) is 5 μm. BM opening = 4 μm, which makes it possible to widen the opening as compared with the case of the conventional liquid crystal display device 10 shown in FIG.

  FIG. 5 is a signal waveform diagram for explaining the operation of the liquid crystal display device according to the first embodiment.

  In FIG. 5, the source bus line 21 corresponds to a signal voltage (display voltage) c corresponding to the third picture element part, a signal voltage (display voltage) a corresponding to the first picture element part, and a second picture element part. The signal voltage (display voltage) b to be applied is applied in time division in this order.

  First, during a period in which a high level voltage (ON voltage) for turning on the TFT 25 is applied to the first gate bus line 22a and the second gate bus line 22b, the third TFT 25c and the fourth TFT 25d are connected to the third picture element portion. Thus, the video signal voltage c applied to the source bus line 21 is written.

  Next, during the period when the ON voltage is applied to the first gate bus line 22a, the video signal voltage a applied to the source bus line 21 via the first TFT 25a is written in the first picture element portion.

  Thereafter, during the period when the ON voltage is applied to the second gate bus line 22b, the video signal voltage b applied to the source bus line 21 via the second TFT 25b is written in the second picture element portion.

  In this way, writing to each picture element part is performed in the third picture element part → first picture element part → second picture element part. That is, a first period in which a driving voltage (high level voltage) is applied only to the first gate bus line 22a, a second period in which a driving voltage (high level voltage) is applied only to the second gate bus line 22b, A scanning line in which a third period in which a drive voltage (high level voltage) is applied to both the first gate bus line 22a and the second gate bus line 22b is repeated in the order of the third period, the first period, and the second period. It has a drive circuit. Although the display quality is inferior to this, writing to each picture element part may be performed in the order of the third picture element part → the second picture element part → the first picture element part. That is, a scan line driver circuit that repeats in the order of the third period, the first period, and the second period may be included.

  By the way, in the first picture element part to the third picture element part shown in FIG. 3, in the third picture element part, the source bus line 21 and the picture element electrode 24c are electrically connected via the two TFTs 25c and 25d. It has come to be.

  For example, when the TFTs 25a and 25b in which the potential reached to the picture element electrodes 24a and 24b is 99.5% of the signal line potential in the first picture element part and the second picture element part, the same TFTs 25a and 25b are used. Are disposed in the third picture element portion as TFTs 25c and 25d, the ultimate potential is 99.5% or less. In this case, even when white / black / gray is displayed on the liquid crystal panel having the RGB picture element portion, the display is shifted to a specific color.

  As methods for avoiding this, there are the following methods (1) to (5).

(1) A method in which the period during which the signal voltage c is written in the third picture element portion in FIG. 5 is made longer than the other periods, that is, a method in which the length of the third period is set longer than the other periods,
(2) High charge to the extent that the potential difference to the pixel electrodes 24a, 24b and 24c with respect to the signal line potential (the potential of the source bus line 21) does not appear in the display in the first to third pixel portions In the method of arranging TFTs having a capacity (for example, size) capable of, that is, the first to fourth TFTs 25a to 25d, a difference in potentials reached to the pixel electrodes 24a, 24b and 24c with respect to the potential of the source bus line 21 appears in the display. A method to make the transistor size as high as possible,
(3) A method of disposing a TFT capable of high charge (for example, size) only in the third picture element portion, that is, the third TFT 25c and the fourth TFT 25d are connected to the picture element electrode 24c with respect to the potential of the source bus line 21. A method of setting the transistor size so as to allow high charge so that the potential difference does not appear on the display is conceivable.

  As for the second picture element portion, as shown in FIG. 1, the second TFT 25b is connected to the picture element electrode 24b at the wiring cross portion A beyond the first gate bus line 22a, and the wiring cross portion A is first. Since it becomes a capacitive component with respect to the gate bus line 22a, in order to ensure the same arrival potential as that of the first picture element portion, an avoidance method such as the above (1) to (3) is adopted, or (4 It is necessary to reduce the size of the cross part A.

  That is, the period during which the high level voltage of the scanning signal is applied to the gate of the second TFT 24b connected to the pixel electrode 24b at the wiring cross portion A beyond the first gate bus line 22a is the scanning signal to the gate of the first TFT 24a. Is set longer than the period during which the high level voltage is applied.

  In addition, the second TFT 24b connected to the pixel electrode 24b at the wiring cross portion A beyond the first gate bus line 22a shows a difference in potential reached to the pixel electrodes 24a and 24b with respect to the potential of the source bus line 21 in the display. The transistor size is as high as possible.

  Furthermore, the width of the wiring cross portion A is set smaller than that of the wiring connected to the picture element electrode 24a via the first TFT 24a.

  Here, when the method (3) is used, the parasitic capacitance Cgd between the gate and the pixel electrode is different from the other pixel parts, and the potential fluctuation of the pixel electrode due to the voltage change of the gate signal is different. If the difference is large, only the specific picture element portion has a display defect such as flicker.

  In order to avoid this, (5) a method of changing the size of the auxiliary capacitance Ccs and the size of the pixel capacitance Clc in accordance with the size of the parasitic capacitance Cgd between the gate and the pixel electrode can be considered.

  That is, the size of the auxiliary capacitance Ccs and / or the size of the pixel capacitance Clc is set between the gate and the pixel electrode so that each potential variation of the pixel electrodes 24a, 24b and 24c due to the voltage change of the gate signal becomes uniform. The parasitic capacitance Cgd is changed according to the magnitude of the parasitic capacitance Cgd.

In FIG. 1, the auxiliary capacitor is configured by the insulating film between the pixel electrode 24 and the Cs bus line 3, but a configuration without the auxiliary capacitor is also possible.
(Embodiment 2)
In the first embodiment, an auxiliary film is formed by providing an insulating film between the Cs bus line 3 and the pixel electrode 24. However, in the second embodiment, the gate bus line 22 and the pixel electrode 24 are used instead. A case where an auxiliary capacitor is formed by providing an insulating film between the two will be described.

  FIG. 6 is a plan view for explaining a picture element shape in the liquid crystal display device according to Embodiment 2 of the present invention.

  In FIG. 6, the liquid crystal display device 20A is not provided with the Cs bus line 3 as in the first embodiment. Instead, the wide second gate bus line 22c of the adjacent picture element portion and three pictures. The auxiliary electrode is configured by partially overlapping the element electrode 24A via an insulating film. Furthermore, by adjusting the width dimension of the gate bus line 22c to make the overlapping area of the picture element electrode 24A and the gate bus line 22c different, the size of the auxiliary capacitance can be adjusted appropriately.

In addition to the auxiliary capacitance by the Cs bus line 3 and the pixel electrode 24, an auxiliary capacitance by the second gate bus line 22c and the three pixel electrodes 24A may be provided.
(Embodiment 3)
In the first embodiment, two branch portions from the source bus line 21 extending to the TFT 25 are provided. However, in the third embodiment, the branch portion (one location) extending from the source bus line 21 to the TFT 25 has three picture elements. A case where the information is shared by the departments will be described.

  FIG. 7 is a plan view for explaining a picture element shape in the liquid crystal display device according to the third embodiment of the present invention.

In FIG. 7, the liquid crystal display device 20B shares the branch portion of the source bus line 21 extending to the TFTs 25a, 25b, and 25d.
(Embodiment 4)
In the first embodiment, the opening area and the pixel electrode area of the first to third pixel parts are the same, but in the fourth embodiment, they may be different.

  FIG. 8 is a plan view for explaining a picture element shape in a liquid crystal display device according to Embodiment 4 of the present invention.

In FIG. 8, the liquid crystal display device 20 </ b> C is different from the first pixel unit to the third pixel unit in the area of the pixel electrodes 24 a to 24 c and the area of the opening. Thus, a desired display state can be set in each picture element unit.
(Embodiment 5)
In the first embodiment, the branch portion of the source bus line 21 extending to the TFT 25 is provided so as to extend on one side (right side) with respect to the source bus line 21, but in the fifth embodiment, both sides (two sides) of the source bus line 21 are provided. The case where it is provided so as to extend to the right and left sides) will be described.

  FIG. 9 is a plan view for explaining a picture element shape in a liquid crystal display device according to Embodiment 5 of the present invention.

  In FIG. 9, the liquid crystal display device 20 </ b> D is arranged from the left side in order of the first picture element part, the second picture element part, and the third picture element part via the source bus line 21. A branch portion extending to the second TFT 25b and the fourth TFT 25d of the third picture element portion is provided to extend to the right side with respect to the source bus line 21, and a branch portion extending to the first TFT 25a of the first picture element portion is the same source bus line 21. Are provided so as to extend to the left side. Therefore, the third picture element part is arranged on the right side of the second picture element part with the source bus line 21 sandwiched between the first picture element part and the second picture element part. That is, the first to third picture element electrodes 24 a, 24 b and 24 c are distributed in the extending direction by the source bus line 21.

  As described above, according to the first to fifth embodiments, the three primary color RGB picture element parts (first to third picture element electrodes 24a, 24b, and 24c) are used as one pixel part, and the display area is configured with three picture element shapes. The first TFT 25a is connected between the first picture element electrode 24a and the signal line 21, the second TFT 25b is connected between the second picture element electrode 24b and the signal line 21, and the third picture element electrode 24c and the signal line are connected. Between the line 21, the third TFT 25 c and the fourth TFT 25 d are connected in series. By providing two switching elements (third TFT 25c and fourth TFT 25d) in one third of the picture element parts constituting the display screen, the number of signal lines = A, for the liquid crystal display panel of A pixel × B pixel, The display area can be configured with the number of lines of scanning lines = B × 2. Conventionally, the area occupied by the signal line (source bus line 21) can be used as a display area, without reducing the process margin such as the wiring width and the wiring interval, and without increasing the number of constituent films. An opening can be secured and a high aperture ratio can be achieved. Since the total number of signal lines (source bus line 21) and scanning lines (first gate bus line 22a and second gate bus line 22b or 22c) is also reduced, the manufacturing yield including driver ICs is improved and the frame is narrowed. Can be achieved. Accordingly, a liquid crystal display device capable of ensuring a sufficient aperture ratio can be obtained even with a high-definition liquid crystal panel having a small size of one picture element portion.

  In the first to fifth embodiments, the picture element electrodes are the first to third picture element electrodes 24a to 24c. However, the picture element electrodes are not limited to this, and four or more including the first to third picture element electrodes 24a to 24c. A picture element unit may be provided.

  For example, four or more picture element parts are provided as picture element electrodes as in a configuration example in which six picture element parts = RGB × 2 is one unit.

  As mentioned above, although this invention has been illustrated using preferable Embodiment 1-5 of this invention, this invention should not be limited and limited to this Embodiment 1-5. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments 1 to 5 of the present invention. Patents, patent applications, and documents cited herein should be incorporated by reference in their entirety, as if the contents themselves were specifically described herein. Understood.

  The present invention is a conventional liquid crystal display device having a small size, high definition, and a relatively small picture element size, and a conventional electronic information device that is a mobile device such as a digital camera, a video camera, and a mobile phone device using the same. By reducing the number of signal lines compared to the liquid crystal display device and allocating the pixel area occupied by the signal lines to the display area, the process margins such as the wiring width and wiring interval are not reduced, and the constituent film Without increasing the aperture, it is possible to secure an opening and increase the aperture ratio. Furthermore, by reducing the total number of signal lines and scanning lines, it is possible to improve the manufacturing yield including the driver IC and reduce the frame.

It is a principal part top view for demonstrating the picture element shape in the liquid crystal display device which concerns on Embodiment 1 of this invention. FIG. 2 is a cross-sectional view taken along line A-A ′ of FIG. 1. FIG. 2 is an equivalent circuit diagram of one pixel portion in the liquid crystal display device of FIG. 1. (A) And (b) is a figure which shows the structural example of the liquid crystal panel in the liquid crystal display device of FIG. It is a signal waveform diagram for demonstrating operation | movement of the liquid crystal display device of FIG. It is a top view for demonstrating the picture element shape in the liquid crystal display device which concerns on Embodiment 2 of this invention. It is a top view for demonstrating the pixel shape in the liquid crystal display device which concerns on Embodiment 3 of this invention. It is a top view for demonstrating the pixel shape in the liquid crystal display device which concerns on Embodiment 4 of this invention. It is a top view for demonstrating the pixel shape in the liquid crystal display device which concerns on Embodiment 5 of this invention. It is a principal part top view for demonstrating the picture element shape in the conventional liquid crystal display device. It is A-A 'line sectional drawing of FIG. FIG. 11 is an equivalent circuit diagram of one pixel portion in the liquid crystal display device of FIG. 10. It is a signal waveform diagram for demonstrating operation | movement of the conventional liquid crystal display device. It is a figure which shows the structural example of the liquid crystal panel in the conventional liquid crystal display device, (a) is a screen figure which shows the magnitude | size of this liquid crystal panel, (b) is an enlarged plan view which expanded the A section of (a). It is.

Explanation of symbols

20, 20A, 20B, 20C, 20D Liquid crystal display device 21 Source bus line 22 Gate bus line 22a First gate bus line 22b Second gate bus line 22c Third gate bus line 3 Cs bus line 24 Picture element electrode 24a First picture Element electrode 24b Second picture element electrode 24c Third picture element electrode 25 TFT
25a 1st TFT
25b 2nd TFT
25c 3rd TFT
25d 4th TFT

Claims (24)

A plurality of signal lines and a plurality of scanning lines intersect with each other and are arranged in a matrix,
In the pixel area provided at each intersection of the signal line and the scanning line, the pixel electrode is selected by the scanning signal from the scanning line and the pixel electrode is driven by the image signal from the signal line. In a liquid crystal display device having a switching element to enable,
At least first and second scanning lines are provided as the scanning lines,
For each pixel region, at least first to third pixel electrodes are provided as the pixel electrodes, and the switching element applies each display voltage from the signal line to the at least first to third pixel electrodes. A liquid crystal display device that can be supplied. First to fourth switching elements are provided as the switching elements in the pixel regions provided at each intersection of the signal lines and the scanning lines,
The first switching element selected by a scanning signal of the first scanning line is connected between the first pixel electrode and the signal line,
The second switching element selected by the scanning signal of the second scanning line is connected between the second pixel electrode and the signal line,
The third switching element selected by the scanning signal of the first scanning line and the fourth switching element selected by the scanning signal of the second scanning line between the third pixel electrode and the signal line The liquid crystal display device according to claim 1, wherein the two are connected in series.   The liquid crystal display device according to claim 1, wherein each display voltage is supplied to the signal line in a time-sharing manner.   3. The liquid crystal display device according to claim 1, wherein the first to third picture element electrodes are arranged along an extending direction of the first scanning line and the second scanning line.   5. The liquid crystal display device according to claim 1, wherein the first to third picture element electrodes are arranged in a region surrounded by the signal lines and the scanning lines.   5. The liquid crystal display device according to claim 1, wherein the first to third picture element electrodes are distributed in the extending direction by the signal lines.   7. The liquid crystal display device according to claim 1, wherein the first to third picture element electrodes correspond to picture element portions of three kinds of colors.   The liquid crystal display device according to claim 7, wherein the three kinds of colors are three primary colors R, G, and B.   The liquid crystal display device according to claim 1, wherein the first to third pixel electrodes have the same or different pixel electrode shapes.   A first period in which a drive voltage is applied only to the first scan line, a second period in which a drive voltage is applied only to the second scan line, and both the first scan line and the second scan line Scanning in which the third period in which the drive voltage is applied is repeated in the order of the third period, the first period, and the second period, or the order of the third period, the second period, and the first period. The liquid crystal display device according to claim 1, further comprising a line drive circuit.   The liquid crystal display device according to claim 10, wherein a length of the third period is set longer than other periods.   3. The liquid crystal display device according to claim 2, wherein the first to fourth switching elements are transistors capable of being charged to a high degree so that a difference in potential reached to the pixel electrode with respect to the potential of the signal line does not appear in display.   3. The liquid crystal display device according to claim 2, wherein the third and fourth switching elements are transistors capable of being charged to a high degree such that a difference in potential reached to the pixel electrode with respect to the potential of the signal line does not appear in display.   The first to fourth switching elements are composed of transistors, and a driving voltage is applied to the gate of a transistor that is connected to the pixel electrode at a wiring crossing section across one scanning line of the pair of scanning lines. The liquid crystal display device according to claim 2, wherein the period for which the driving voltage is applied is set longer than the period for which the driving voltage is applied to the other transistors.   The first to fourth switching elements are constituted by transistors, and are connected to the picture element electrodes at a wiring cross portion beyond at least one scanning line of the pair of scanning lines. 3. The liquid crystal display device according to claim 2, wherein the transistor is a transistor that can be charged to such a high degree that a difference in potential reached to the pixel electrode with respect to the potential of the signal line does not appear on the display.   The liquid crystal display device according to claim 14, wherein the wiring cross portion is set to have a width size smaller than a wiring connected to a pixel electrode through the other transistor.   3. The liquid crystal display device according to claim 1, wherein at least one of the first scanning line and the second scanning line and the first to third pixel electrodes constitute an auxiliary capacitor through an insulating film.   The liquid crystal according to claim 1, wherein an auxiliary capacitance line is provided in parallel to the scanning line, and the first to third pixel electrodes and the auxiliary capacitance line constitute an auxiliary capacitance via an insulating film. Display device.   The liquid crystal according to claim 17 or 18, wherein the size of each auxiliary capacitance for each pixel electrode between the first to third pixel electrodes and the scanning line or the auxiliary capacitance line is the same or different. Display device.   The switching element is composed of four transistors, and the auxiliary capacitance is a parasitic capacitance between the gate and the pixel electrode so that each potential variation of the first to third pixel electrodes due to a voltage change of the gate signal becomes uniform. The liquid crystal display device according to claim 17, wherein the liquid crystal display device is changed according to the size of the liquid crystal display device.   The liquid crystal display device according to claim 2, wherein one or two branch portions from the signal line extending to the first, second, and fourth switching elements are provided.   3. The liquid crystal display device according to claim 1, wherein an area of each of the first to third pixel electrodes and an area of the opening thereof are the same or different.   The liquid crystal display device according to claim 1, wherein four or more picture element portions including the first to third picture element electrodes are provided as the picture element electrodes.   24. An electronic information device in which the liquid crystal display device according to claim 1 is used for a display unit.

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