DISPLAY DEVICE
20230161204 · 2023-05-25
Inventors
Cpc classification
G02F1/1368
PHYSICS
G02F1/133707
PHYSICS
G02F1/13306
PHYSICS
G02F1/136227
PHYSICS
G02F1/1337
PHYSICS
G02F1/134381
PHYSICS
G02F1/134363
PHYSICS
International classification
G02F1/133
PHYSICS
G02F1/1337
PHYSICS
Abstract
A display device is provided and includes first and second substrates; a liquid crystal layer filled between the first and second substrates; a counter electrode pattern formed on the first substrate; scanning lines extending in a first direction; signal lines; and a first pixel electrode pattern and a second pixel electrode pattern formed on the first substrate, wherein the first pixel electrode pattern and the second pixel electrode pattern are located in line symmetry with respect to a first scanning line of the scanning lines.
Claims
1. A display device comprising: a substrate; a first pixel with a first electrode on the substrate; a second pixel with a second electrode on the substrate, the first pixel being adjacent to the second pixel; and a first scanning line between the first pixel and the second pixel, wherein the first pixel electrode includes a first slit, the second pixel electrode includes a second slit, the first slit has: a first end at a first scanning line side; a second end at an opposite side of the first end; and a first portion extending from the first end to the second end in a first direction, the second slit has: a third end at the first scanning line side; a fourth end at a an opposite side of the third end; and a second portion extending from the third end to the second end in a send direction, and the first direction is different from the second direction.
2. The display device according to claim 1, wherein the first pixel and the second pixel are arranged in a third direction, the first direction is inclined at a first angle relative to the third direction, the second direction is inclined at a send angle relative to the third direction, and the second angle is an opposite direction of the first angle.
3. The display device according to claim 1, wherein the first end overlaps the first scanning line.
4. The display device according to claim 3, wherein the third end overlaps the first scanning line.
5. The display device according to claim 1, wherein the third end overlaps the first scanning line.
6. The display device according to claim 1, wherein the first slit bends between the first end and the second end.
7. The display device according to claim 6, wherein the second slit bends between the third end and the fourth end.
8. The display device according to claim 7, wherein the first and second pixel electrodes have a vertical mirror structure with respect to the first scanning line.
9. The display device according to claim 1, further comprising a second scanning line, wherein the first pixel is located between the first scanning line and the second scanning line, and the second end overlaps the second scanning line.
10. The display device according to claim 1, further comprising a second scanning line, wherein the first pixel is located between the first scanning line and the second scanning line, and the second end does not overlap the second scanning line.
11. The display device according to claim 1, further comprising a counter electrode that is disposed in a same layer of the first pixel electrode.
12. The display device according to claim 1, further comprising a counter electrode that is disposed in a different layer of the first pixel electrode.
13. A display device comprising: a substrate; a first pixel with a first electrode on the substrate; a second pixel with a second electrode on the substrate, the first pixel being adjacent to the second pixel; and a scanning line between the first pixel and the second pixel, wherein the first pixel electrode includes a plurality of first slits, the second pixel electrode includes a plurality of second slits, each of the first slits has: a first end at a scanning line side; a second end at an opposite side of the first end; and a first portion extending from the first end to the second end in a first direction, each of the second slits has: a third end at the scanning line side; a fourth end at an opposite side of the third end; and a second portion extending from the third end to the second end in a send direction, and the first direction is different from the second direction.
14. The display device according to claim 13, wherein the first pixel and the second pixel are arranged in a third direction, the first direction is inclined at a first angle relative to the third direction, the second direction is inclined at a send angle relative to the third direction, and the second angle is an opposite direction of the first angle.
15. The display device according to claim 13, wherein the first end overlaps the scanning line.
16. The display device according to claim 15, wherein the third end overlaps the scanning line.
17. The display device according to claim 13, wherein each of first slits bends between the first end and the second end.
18. The display device according to claim 17, wherein each of second slits bends between the third end and the fourth end.
19. The display device according to claim 18, wherein the first and second pixel electrodes have a vertical mirror structure with respect to the first scanning line.
Description
BRIEF DESCRIPTION OF THE FIGURES
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DETAILED DESCRIPTION
[0051] The present application will be described as follows with reference to the drawings according to an embodiment.
[0052] (A) Appearance Example of Liquid Crystal Panel Module and Panel Structure
[0053] (B) Pixel Structure Example 1: Single Domain Structure
[0054] (C) Pixel Structure Example 2: Pseudo Dual Domain Structure
[0055] (D) Pixel Structure Example 3: Dual Domain Structure
[0056] (E) Pixel Structure Example 4: Dual Domain Structure
[0057] (F) Pixel Structure Example 5: Different Sectional Structure
[0058] (G) Pixel Structure Example 6: Different Sectional Structure
[0059] (H) Pixel Structure Example 7: Different Pixel Structure Example
[0060] (I) Other Examples
[0061] Elements which are not provided with particular drawings or descriptions herein are realized by existing techniques in the relevant technical field. Embodiments described below are only exemplary, and the application is not limited thereto.
(A) Appearance Example of Liquid Crystal Panel Module and Panel Structure
[0062]
[0063] Note that only one substrate on the light emission side may be a transparent substrate, and the other substrate may be a nontransparent substrate.
[0064] Further, the liquid crystal panel 51 is provided with an FPC (Flexible Printed Circuit) 57 for inputting an external signal or driving power, if necessary.
[0065]
[0066] The pixel array section 63 has a matrix structure in which white units each constituting one pixel for display are arranged in M rows×N columns. In this specification, the row refers to a pixel row of 3×N subpixels 71 arranged in the X direction of the drawing. The column refers to a pixel column of M subpixels 71 arranged in the Y direction of the drawing. Of course, the values M and N are determined depending on the display resolution in the vertical direction and the display resolution in the horizontal direction.
[0067] The signal line driver 65 is used to apply a signal potential Vsig corresponding to a pixel gradation value to signal lines DL. In this embodiment, the signal lines DL are arranged so as to extend in the Y direction of the drawing.
[0068] The gate line driver 67 is used to apply control pulses for providing the write timing of the signal potential Vsig to scanning lines WL. In this embodiment, the scanning lines WL are arranged so as to extend in the X direction of the drawing.
[0069] A thin film transistor (not shown) is formed in each subpixel 71. The thin film transistor has a gate electrode connected to a corresponding one of the scanning lines WL, one main electrode connected to a corresponding one of the signal lines DL, and the other main electrode connected to the pixel electrode 13.
[0070] The timing controller 69 is a circuit device which supplies driving pulses to the signal line driver 65 and the gate line driver 67.
(B) Pixel Structure Example 1
[0071]
[0072] Thus, the sectional structure of the pixel region is the same as shown in
[0073] The pixel structure shown in
[0074] The pixel electrode 13 has a contact portion 13C at the upper end of the pixel region in the drawing. The contact portion 13C is connected to the thin film transistor (not shown) through a contact 25 formed at the central portion thereof.
[0075] One end of the contact portion 13C is connected to the connection portion 13B, and the other end of the contact portion 13C is connected to three electrode branches 13A.
[0076] The three electrode branches 13A are electrode branches 13A other than two electrode branches 13A at both ends from among the five electrode branches 13A.
[0077] The contact portion 13C has a large pattern area. For this reason, at the boundary between the contact portion 13C and two slits 31 which are formed by the three electrode branches 13A directly connected to the contact portion 13C, alignment stability is likely to be weakened. The weak alignment stability means that reverse twist which occurs when liquid crystal is pressed down is likely to grow.
[0078] Accordingly, in the pixel structure example of
[0079] The two slits 31 are slits where the growth of reverse twist is likely to dominantly appear when liquid crystal is pressed down.
[0080] However, with the partial connection branch 81, even though liquid crystal is pressed down, the growth of the reverse twist can be confined within the slit 31 on the contact portion 13C side and can be prevented from reaching around the center of the pixel region.
[0081] As will be understood from the comparison of
[0082] As a result, with this pixel structure, the display quality can be significantly improved over the liquid crystal panel.
[0083] It is preferable that the space formed between the contact portion 13C and the partial connection branch 81 is as small as possible. For example, the space is preferably small to be close to the manufacturing limit. This is because, the narrower the space, the more the area of the pixel region to which the alignment regulation force is applied can be increased.
[0084] Similarly, it should suffice that the partial connection branch 81 can divide the region into two parts, so the pattern width of the partial connection branch 81 is preferably thin to be close to the manufacturing limit.
(C) Pixel Structure Example 2
[0085]
[0086] The pixel electrode 13 has the same basic pattern structure as the above-described pixel structure example (
[0087] Meanwhile, in the above-described pixel structure example (
[0088] The pixel structure example of
[0089] The inclination direction is inverted between two upper and lower pixel regions arranged in the Y-axis direction. That is, a pattern which is inclined in the clockwise direction with respect to the Y-axis direction and a pattern which is inclined in the counterclockwise direction with respect to the Y-axis direction are alternately disposed along the Y-axis direction. In other words, the pixel regions in this embodiment have a vertical mirror structure with respect to the scanning line 23 extending in the X-axis direction.
[0090]
[0091] Of course, a pixel region where the pattern in the pixel region is inclined in the counterclockwise direction with respect to the Y-axis direction is formed above and below the pixel region shown in
[0092] As described above, the rotation direction of the liquid crystal molecules is inverted between the two upper and lower pixel regions, so a liquid crystal panel with a wide viewing angle can be realized.
[0093] The above-described pixel structure constitutes a pseudo dual domain structure.
[0094] Hereinafter, the preferable relationship between the alignment direction of the liquid crystal layer 7 and the extension direction of each slit 31 formed by the electrode branches 13A will be described. Note that the alignment direction of the liquid crystal layer 7 (also referred to as “alignment direction of liquid crystal”) is defined by the orientation of dielectric anisotropy of liquid crystal, and refers to a direction with a large dielectric constant.
[0095] In the pixel structure of
[0096] This value is determined by the following experiment. Hereinafter, the characteristics confirmed by the inventors will be described.
[0097]
[0098] From the experiment result shown in
[0099] Meanwhile, when the cross angle α is equal to or larger than 7°, it has been confirmed that display irregularity due to the reverse twist phenomenon can disappear by itself. For this reason, in
[0100] When the cross angle α is 7°, the time until display irregularity disappears is 3.5 [seconds]. The experiment shows that, as the cross angle α becomes larger, the time until display irregularity disappears is shortened.
[0101] For example, when the cross angle α is 10°, it has been confirmed that display irregularity disappears in 3 [seconds]. When the cross angle α is 15°, it has been confirmed that display irregularity disappears in 2.5 [seconds]. When the cross angle α is 20°, it has been confirmed that display irregularity disappears in 1.5 [seconds].
[0102] From this, it can be seen that, as the cross angle α becomes larger, the alignment regulation force of the liquid crystal molecules in the transverse electric field display type liquid crystal panel can be increased.
[0103]
[0104] As shown in
[0105] However, the larger cross angle α is not necessarily the better.
[0106]
[0107] In
[0108] As shown in
[0109] From the above-described characteristics, the inventors have considered it preferable that the cross angle α between the extension direction of the slit 31 and the alignment direction of the liquid crystal layer 7 be equal to or larger than 7° and equal to or smaller than 15°. If this condition is satisfied, the relative transmittance and the time until display irregularity disappears can be maintained appropriately.
[0110] Therefore, a liquid crystal panel can be realized in which, even though the reverse twist phenomenon due to finger press or the like disturbs the arrangement of the liquid crystal molecules, the disturbance can be eliminated by itself in several seconds.
[0111]
(D) Pixel Structure Example 3
[0112]
[0113] However, in the third pixel structure, each pixel region has a dual domain structure. That is, the pixel electrode 13 is bent around the center of the pixel region (in the drawing, a rectangular region indicated by a broken line) in the Y-axis direction.
[0114] In
[0115] The pixel structure shown in
[0116] Under this condition, the cross angle α between the alignment direction of the liquid crystal layer 7 and the extension direction of the slit 31 is set to be equal to or larger than 7°. Of course, from the viewpoint of display performance, it is preferable that the cross angle α is equal to or larger than 7° and smaller than 15°. Further, it is assumed that the alignment direction of the liquid crystal layer 7 is parallel to the Y-axis direction.
[0117] In the case of the pixel structure with a dual domain structure, the rotation direction of the liquid crystal molecules is inverted between the upper half portion and the lower half portion of the pixel region. That is, while the liquid crystal molecules in the upper half portion of the pixel region of the drawing rotate in the counterclockwise direction by the application of an electric field, and the liquid crystal molecules in the lower half portion of the pixel region of the drawing rotate in the clockwise direction by the application of an electric field.
[0118] As described above, the rotation direction of the liquid crystal molecules is inverted, so the amount of light per pixel can be made uniform even when the display screen is viewed at any angle. Therefore, a liquid crystal panel with a wider viewing angle than the first pixel structure can be realized.
[0119] Of course, as described above, the relationship between the alignment direction of the liquid crystal layer 7 and the extension direction of the slit 31 is optimized. Therefore, even though the reverse twist due to finger press or the like disturbs the arrangement of the liquid crystal molecules, the disturbance can be eliminated by itself in several seconds.
(E) Pixel Structure Example 4
[0120]
[0121] A difference is that a connection branch 13D is additionally provided so as to transversely connect the bend points of the electrode branches 13A to each other.
[0122] The reason is as follows. In the third pixel structure of
[0123] Meanwhile, in the pixel structure example of
[0124] For this reason, it is possible to eliminate disturbance of the arrangement of the liquid crystal molecules at the boundary between the domains. As a result, with the pixel structure shown in
(F) Pixel Structure Example 5
[0125] In the above-described four pixel structure examples, the FFS type liquid crystal panel having the sectional structure described with reference to
[0126] Alternatively, as shown in
[0127] In
[0128] That is, the electrode branches 15A of the counter electrode 15 are disposed so as not to overlap the electrode branches 13A of the pixel electrode 13 in the pixel region. Of course, there is no difference in the electric field formed between the pixel electrode 13 and the counter electrode 15.
(G) Pixel Structure Example 6
[0129] In the above-described pixel structure examples, the description has been made of the pixel structure in which the pixel electrode 13 and the counter electrode 15 are formed in different layers.
[0130] Alternatively, the technique which has been suggested by the inventors may also be applied to a transverse electric field display type liquid crystal panel in which the pixel electrode 13 and the counter electrode 15 are formed in the same layer.
[0131]
[0132] That is, the liquid crystal panel 101 includes two glass substrates 3 and 5, and a liquid crystal layer 7 filled so as to be sandwiched with the glass substrates 3 and 5. A polarizing plate 9 is disposed on the outer surface of each substrate, and an alignment film 11 is disposed on the inner surface of each substrate.
[0133] In the liquid crystal panel 101 of
[0134] Of these, the pixel electrode 13 is structured such that one ends of comb-shaped four electrode branches 13A are connected to each other by a connection portion 13B.
[0135] Meanwhile, the counter electrode 15 in the pixel region is comb-shaped, similarly to
[0136] As described above, in this pixel structure example, the electrode branches 13A of the pixel electrode 13 and the electrode branches 15A of the counter electrode 15 are disposed in the same layer so as to alternately appear in the X-axis direction. With this electrode structure, a parabolic electric field is generated between the electrode branches 13A of the pixel electrode 13 and the electrode branches 15A of the counter electrode 15. In
[0137] As shown in
[0138] With this pixel structure, a liquid crystal panel can be realized in which a reverse twist line is unlikely to occur around the center of the pixel region due to external pressure, such as finger press or the like.
(H) Pixel Structure Example 7
[0139] In the above-described six pixel structure examples, a case where the extension direction of each slit 31 formed by the electrode branches 13A of the pixel electrode 13 is parallel to the Y-axis direction or crosses the Y-axis direction at an acute angle has been described.
[0140] Alternatively, the extension direction of each slit 31 formed by the electrode branches 13A of the pixel electrode 13 may be parallel to the X-axis direction or may cross the X-axis direction at an acute angle.
[0141]
[0142] Description will be made again with reference to
[0143] In this pixel structure example, the alignment regulation force is likely to be weakened at the boundary between the contact portion 13C and the electrode branch 13A directly extending from the contact portion 13C.
[0144] However, the partial connection branch 81 is formed so as to transverse the electrode branches 13A, so, as in the above-described pixel structure examples, a reverse twist line due to the application of external pressure in the relevant region can be effectively prevented from growing.
(I) Other Examples
(I-1) Substrate Material
[0145] In the above description of the examples, the substrate is a glass substrate, but a plastic substrate or other substrates may be used.
(I-2) Alignment Direction 1 of Alignment Film
[0146] Of the above-described examples, in the case of the pixel structure example 1 (
[0147] Of course, when the cross angle α is equal to or larger than 7°, similarly to the pixel structure example 2 (
(I-3) Alignment Direction 1 of Alignment Film
[0148] Of the above-described examples, in the case of the pixel structure example 2 (
[0149] Alternatively, the cross angle α may be smaller than 7°. In this case, display irregularity remains, but as described with reference to
(I-4) Product Examples
[0150] In the above description, various pixel structures capable of generating a transverse electric field have been described. Hereinafter, description will be provided for electronic apparatuses in which a liquid crystal panel having the pixel structure according to the examples (with no driving circuit mounted therein) or a liquid crystal panel module (with a driving circuit mounted therein) is mounted.
[0151]
[0152] The configuration of the operation input unit 117 varies depending on the product type. A GUI (Graphic User Interface), switches, buttons, a pointing device, and other operators may be used as the operation input unit 117.
[0153] It should be noted that the electronic apparatus 111 is not limited to an apparatus designed for use in a specific field insofar as it can display an image or video generated inside or input from the outside.
[0154]
[0155] The electronic apparatus 111 may be, for example, a digital camera.
[0156] The digital camera 131 includes a protective cover 133, an imaging lens section 135, a display screen 137, a control switch 139, and a shutter button 141. Of these, the display screen 137 corresponds to the liquid crystal panel according to the embodiment.
[0157] The electronic apparatus 111 may be, for example, a video camcorder.
[0158] The video camcorder 151 includes an imaging lens 155 provided to the front of a main body 153 so as to capture the image of the subject, a photographing start/stop switch 157, and a display screen 159. Of these, the display screen 159 corresponds to the liquid crystal panel according to the embodiment.
[0159] The electronic apparatus 111 may be, for example, a personal digital assistant.
[0160] The mobile phone 161 includes an upper housing 163, a lower housing 165, a connection portion (in this example, a hinge) 167, a display screen 169, an auxiliary display screen 171, a picture light 173, and an imaging lens 175. Of these, the display screen 169 and the auxiliary display screen 171 correspond to the liquid crystal panel according to the embodiment.
[0161] The electronic apparatus 111 may be, for example, a computer.
[0162] The notebook computer 181 includes a lower housing 183, an upper housing 185, a keyboard 187, and a display screen 189. Of these, the display screen 189 corresponds to the liquid crystal panel according to the embodiment.
[0163] In addition to the above-described electronic apparatuses, the electronic apparatus 111 may be, for example, a projector, an audio player, a game machine, an electronic book, an electronic dictionary, or the like.
[0164] It should be understood that various changes and modifications to the presently preferred embodiments described herein will be apparent to those skilled in the art. Such changes and modifications can be made without departing from the spirit and scope and without diminishing its intended advantages. It is therefore intended that such changes and modifications be covered by the appended claims.