JP5062667B2 - Transflective LCD panel - Google Patents

Description

The present invention relates to a transflective liquid crystal display panel, and more particularly, to a transflective liquid crystal display panel of MVA (Multi-domain Vertically Aligned) system that has good manufacturing efficiency, good pixel electrode reliability, and a long lifetime.

In recent years, the application of liquid crystal display devices has rapidly spread not only in information communication equipment but also in general electric equipment. Since a liquid crystal display device does not emit light by itself, a transmissive liquid crystal display device having a backlight is often used. However, since the power consumption of the backlight is large, a reflective liquid crystal display device that does not require a backlight is used to reduce the power consumption, particularly for a portable type. Since the device uses external light as a light source, it is difficult to see in a dark room. Thus, in recent years, development of a transflective liquid crystal display device having both transmissive and reflective properties has been underway.

A liquid crystal display panel used in the transflective liquid crystal display device has a transmissive region having a pixel electrode and a reflective region having both a pixel electrode and a reflector in one pixel region, and is dark. Since the backlight is turned on at the place and the image is displayed using the transmission area of the pixel area, the image is displayed using the outside light in the reflection area without turning on the backlight at the bright place. Since there is no need to always turn on the backlight, there is an advantage that power consumption can be greatly reduced.

By the way, the demand for a wide viewing angle for a liquid crystal display panel has not been so high in the past because of the limited number of users of small display units in mobile devices such as mobile phones. In mobile devices that are becoming increasingly sophisticated, the demand for a wide viewing angle of a liquid crystal display panel in a display section has been rapidly increasing. Based on such demands for wide viewing angles for mobile devices, MVA (Multi-domain Vertically Aligned) type transflective liquid crystal display panels are used instead of TN type liquid crystal display panels that have been widely used in mobile devices. Development is also in progress (see Patent Documents 1 and 2 below).

Here, an MVA transflective liquid crystal display panel disclosed in Patent Document 2 below will be described with reference to FIGS. 8A is a perspective view showing a schematic structure of the MVA-type transflective liquid crystal display panel 50, and FIG. 8B is a tilt of the liquid crystal when an electric field is applied to the liquid crystal in the liquid crystal layer. FIG. 9 is a schematic view showing a state body, and FIG. 9 is a cross-sectional view taken along line BB of FIG.

In the transflective liquid crystal display panel 50, a connection region (non-transmission region) 53 is provided between the reflection region 51 and the transmission region 52, and the reflection region 51 and the transmission region 52 define the connection region 53. Is continuous through. A first opening region 56 is formed in the pixel electrode 55 of the first substrate 54 in the transflective liquid crystal display panel 50 as a region where the pixel electrode 55 is not formed. The first opening area 56 constitutes a first alignment dividing means, and is formed across the reflection area 51 and the transmission area 52 with the connection area 53 interposed therebetween.

As a result, the pixel electrode 55 a in the reflective region 51 and the pixel electrode 55 in the transmissive region 52.
and b are connected to each other through one connecting portion 57 extending in the length direction of the transflective liquid crystal display panel 50.

On the counter electrode 59 of the second substrate 58, second opening regions 60a and 60b are formed to face the pixel electrode 55a in the reflection region 51 and the pixel electrode 55b in the transmission region 52, respectively. The second opening regions 60a and 60b constitute a second alignment dividing unit. The second opening regions 60a and 60b are configured as cross-shaped slits, and in the vertical direction,
The center of the opening area 60a is arranged to coincide with the center of the pixel electrode 55a, and the center of the second opening area 60b is arranged to coincide with the center of the pixel electrode 55b.

According to the transflective liquid crystal display panel 50, when an electric field is applied to the liquid crystal 61 of the liquid crystal layer, as shown in FIGS. 8B and 9, on the first opening region 56 in the connecting portion 53,
The liquid crystal is inclined in the direction of the line 57 on the counter electrode 59 side, and the reflective region 51 and the transmissive region 5
2, the counter electrode 59 is inclined to the center of the region corresponding to the reflection region 51 or the center of the region corresponding to the transmission region 52. As described above, in the transflective liquid crystal display panel 50, the alignment direction of the liquid crystal molecules is determined, so that deterioration of visual characteristics and response speed can be reduced.

The MVA transflective liquid crystal display panel 50 described above includes a connecting portion 53 between the reflective region 51 and the transmissive region 52 on the first substrate 54 side, and, as is well known, the cell gap d1 in the reflective region 51 and The display image quality in the reflection area 51 and the display image quality in the transmission area are adjusted to be the same so that the relationship with the cell gap d2 in the transmission area is d1 = (d2) / 2.

10 to 14 are examples of an MVA type transflective liquid crystal display panel in which a top coat layer for adjusting the cell gap is provided on the second substrate side. FIG. 10 is a plan view of one pixel that is seen through a second substrate of a conventional transflective liquid crystal display panel in which a top coat layer for adjusting a cell gap is provided on the second substrate side. The pixel electrode is hatched. In order to make it easy to identify the components shown in FIG. 10, FIG. 11 shows hatching only on the reflector, FIG. 12 shows hatching only on the pixel electrode, and FIG. 13 shows hatching only on the auxiliary capacitor and the auxiliary capacitor line. Yes. 14 is a cross-sectional view taken along the line CC of FIG.

In the transflective liquid crystal display panel 70, a plurality of scanning lines 72 and signal lines 73 are arranged in a matrix form directly or through an inorganic insulating film 74 on a glass substrate 71 having a transparent insulating property as a first substrate. Is formed. Here, a region surrounded by the scanning line 72 and the signal line 73 corresponds to one pixel, and a TFT (Thin Film Transistor) serving as a switching element is formed for each pixel. The surface is covered with a protective insulating film 15.

A fine uneven portion is formed on the surface of the reflective region 76 so as to cover the scanning line 72, the signal line 73, the inorganic insulating film 74, the protective insulating film 75, etc. In the transmissive region 77 and the non-transmissive region 78. An interlayer film 79 made of an organic insulating film having a flat surface is laminated. In FIG. 10 to FIG. 14, the uneven portion of the reflection region 76 is omitted. A contact hole 80 is provided in the interlayer film 79 at a position corresponding to the drain electrode D of the TFT. In each pixel, the reflection region 7 is formed on the contact hole 80 and on the surface of the interlayer film 79.
6 is provided with a reflecting plate 81 made of, for example, aluminum metal. On the surface of the reflecting plate 81 and the surface of the interlayer film 79 in the transmission region 77, for example, ITO (Indium Tin Oxide) to IZO (InZO)
A transparent pixel electrode 82 made of dium zinc oxide) is formed.

On the reflective region 76 side, an auxiliary capacitor 83 is disposed below the position where the reflective plate 81 of the interlayer film 79 exists, and an auxiliary capacitor adjacent to the non-transmissive region 78 between the reflective region 76 and the transmissive region 77. Is formed. Since the capacitance generated at the intersection 85 between the auxiliary capacitance line 84 and the signal line 73 causes crosstalk, the auxiliary capacitance line 84 at the intersection 85 is narrowed. In plan view, the reflecting plate 81 and the pixel electrode 82 do not contact the reflecting plate and the pixel electrode of the adjacent pixel, and the scanning line 72 and the signal line 73 are slightly overlapped to prevent light leakage. Is formed. The pixel electrode 82 on the transmissive region 77 side is formed so as not to contact the pixel electrode of the adjacent pixel and the reflection plate, slightly overlap the scanning line 72, and not overlap the signal line 73.

Further, in the transflective liquid crystal display panel 70, slits 86 and 86 for regulating the orientation of liquid crystal molecules are provided in the non-transmissive region 78 of the pixel electrode 82, and the pixel electrode 82.
Is substantially divided into a pixel electrode 82a in the reflective region 81 and a pixel electrode 82b in the transmissive region 77, and the pixel electrode 82a in the reflective region 76 and the pixel electrode 82b in the transmissive region 77 are connected via a narrow connecting portion 87. Are electrically connected. Further, the pixel electrode 82 b in the transmission region 77 is divided into two by slits 88 and 88. A vertical alignment film (not shown) is laminated on the surface of the pixel electrode 82 so as to cover all the pixels.

In addition, any one of red (R), green (G), and blue (B) formed corresponding to each pixel on the display area of the transparent glass substrate 89 of the second substrate. A striped color filter layer 90 is provided. In addition, since the color filter layer 90 having the same thickness is used in the reflective region 76 and the transmissive region 77, a top coat layer 91 having a predetermined thickness is provided on a part of the color filter layer 90 in the reflective region 76. The top coat layer 91 is provided over the entire reflection region 76, and the thickness thereof is the thickness of the liquid crystal layer in the reflection region 76, so that the so-called cell gap d 1 is half of the cell gap d 2 of the transmission region 16. That is, d1 = (d2) / 2. In addition, an opaque layer (black matrix) 92 that blocks the passage of light is formed in the opaque region 78 of the second substrate and the color filter layer 90.

In addition, a part of the surface of the color filter layer 90 located in the transmissive region 77 and the reflective region 76.
They are respectively provided projections 93 _1, 93 ₂ and 94 for each part of the surface of the top coat layer 91 for regulating the orientation of the liquid crystal located in the color filter layer 90, topcoat layer 91 and the protrusions 93 ₁ , 93 _2, 94 are sequentially stacked with a common electrode and a vertical alignment film (both not shown).

Then, the first substrate and the second substrate are opposed to each other, a sealing material is provided around both substrates, the two substrates are bonded together, and a liquid crystal 95 having negative dielectric anisotropy is filled between the substrates. Thus, an MVA transflective liquid crystal display panel 70 is obtained. A backlight device having a well-known light source, a light guide plate, a diffusion sheet, and the like (not shown) is disposed below the first substrate.

In this MVA type transflective liquid crystal display panel 70, when no electric field is applied between the pixel electrode 82 and the counter electrode, the major axis of the liquid crystal molecules in the liquid crystal layer is perpendicular to the surface of the pixel electrode and the counter electrode. The light is not transmitted through the liquid crystal, and light is transmitted when an electric field is applied between the pixel electrode and the counter electrode. Further, the slits 86 and 8 of the pixel electrode 82 are eliminated.
6 and the projections 93 ₁ , 93 _2, 94, the liquid crystal molecules are projected from the projections 93 ₁ , 932 ₂ to 9.
4 has a characteristic that the viewing angle becomes very wide.
JP 2003-167253 A (claims, paragraphs [0050] to [0057], FIG. 1) JP 2004-069767 (Claims, paragraphs [0044] to [0053], FIG. 1)

As described above, in the conventional MVA type transflective liquid crystal display panel, since the slit is provided in the vicinity of the boundary between the transmissive region and the reflective region, the connecting portion in which the width of the pixel electrode is narrow (see FIG. 8). Reference numeral “57” or reference numeral “87” in FIG. 10) exists. In general, as shown in FIG. 10, the edge portion of the reflection plate 81 in the reflection region 76 is formed at the end portion of the reflection plate in order to increase the area of the reflection region while increasing the aperture ratio of the transmission region. The pixel electrode is provided so as to be positioned below a portion in contact with the connecting portion 87 where the width of the pixel electrode is narrow (see an enlarged view of FIG. 14). Therefore, the portion where the width of the pixel electrode is narrow is in contact with the edge portion of the reflector (between P1 and P2 in the enlarged view of FIG. 10 and the inclined portion of the enlarged view of FIG. 14). In the present application, when the pixel electrode extends on the reflection plate in this way, the ride-up occurs with a step in the cross-sectional view, and the extended line in the plan view is referred to as a run-up line. Usually, the pixel electrode is formed by sputtering. That is, ITO is scattered by collision of ions moving at a high speed, and a pixel electrode film is formed. Due to this formation method, the film thickness of the ride is thinned, and the disconnection occurs from the end of the narrow ride line at the time of manufacture, transportation and use, and this progresses, and finally the connecting part 87 is disconnected. There is a point. Further, the resist solution by the treatment after the formation of the pixel electrode permeates from the boundary between both edges of the step, which causes a disconnection. This problem does not occur only in the MVA system, but occurs in a display panel in which the pixel electrode rides on the reflector.

The present invention has been made to solve the problems of such a conventional transflective liquid crystal display panel, and the purpose thereof is that disconnection is unlikely to occur at the portion where the pixel electrode is thin,
An object of the present invention is to provide a transflective liquid crystal display panel (especially an MVA transflective liquid crystal display panel) having a good manufacturing efficiency and a long lifetime.

In order to solve the above problems, a transflective liquid crystal display panel according to the present invention has a reflective region and a transmissive region provided at respective positions partitioned by signal lines and scanning lines arranged in a matrix. A transflective liquid crystal display panel having a connecting portion between the pixel electrode in the transmissive region and the pixel electrode in the reflective region, and having a reflective plate under the pixel electrode in the reflective region, occurs ride is the pixel electrode pixel electrode of the reflective region near the edge of the reflecting plate by covering the edge of the reflecting plate is curved in cross section, said run-up line the ride is extending in a plan view Extending to both sides of the connecting portion, providing a step on each ride line, providing a non-transmissive region having a non-transmissive layer between the transmissive region and the reflective region, and forming a step on the ride line on the signal line Near And it provided in the non-transmission region side.

As described above, since the step is provided in the boarding line having a small film thickness, for example, the disconnection along the boarding line is hardly generated so that the perforation having the step is difficult to cut, and the strength against the disconnection is improved.

In addition, since the ride line extends in both directions of the connecting portion and a step is provided in each ride line, it is possible to prevent disconnection at the connecting portion having a narrow width .

Further, said opaque region having opaque layer between the transmissive region and the reflective region is provided, since a step of the riding line provided in the vicinity and the non-transmission region side of the signal line, between the reflection plate and the signal line Light leakage from the gap can be prevented by the existing opaque layer. Therefore, it is not necessary to add a new opaque layer, and a reduction in the aperture ratio can be prevented.

The best mode for carrying out the present invention will be described below with reference to the embodiments and the drawings. However, the examples shown below are not intended to limit the present invention to those described herein, and the present invention can be variously modified without departing from the technical idea shown in the claims. It can be equally applied to the food.

A transflective liquid crystal display panel 10 according to an embodiment will be described with reference to FIGS. FIG. 1 is a plan view of one pixel of the MVA transflective liquid crystal display panel seen through the second substrate, and the reflector and the pixel electrode are hatched. In order to make it easy to identify the components shown in FIG. 1, FIG. 2 hatches only the reflector, FIG. 3 hatches only the pixel electrode,
In FIG. 4, only the auxiliary capacitance and the auxiliary capacitance line are hatched. FIG. 5 is a cross-sectional view taken along the line AA in FIG. However, the same reference numerals are given to the same components as those of the conventional MVA transflective liquid crystal display panel 70 shown in FIGS. 8 to 12, and the detailed description thereof is omitted.

As shown in FIG. 10, the area of the reflector 81 in the conventional example is a pixel electrode 82 in the reflection area 77 in plan view.
It was the same area as a. Therefore, the length of the conventional ride line is P in the enlarged view of FIG.
1, between P2 and the width of the connecting portion. On the other hand, as shown in FIG. 1, the area of the reflector 11 of the present invention is slightly narrower on the connecting portion 87 side than the area of the pixel electrode 12a. For this reason, the length of the boarding line of an Example becomes between P1 and P2 of FIG. 1, and is long.
Therefore, the length of the boarding line having a small film thickness is longer than that of the conventional one, and is not easily disconnected.

In addition, there are steps (between P1-P3 and P4-P5, P6-
Between P2 and P4-P5). For example, in the same way that a perforation having a step is difficult to cut, even if a crack is generated at both ends P1 and P2 of the run-up line when stress is applied from the outside, the crack does not easily progress to P4-P6. Since cracks generated in P1 and P2 are difficult to be connected, disconnection of the connecting portion 87 can be prevented.

Also, the direction of the step at both ends is on the non-transmissive region side. For this reason, since the reflection region 76 is entirely covered with the opaque signal line 73 and the reflection plate 11, the light of the backlight (not shown) does not leak. In FIG. 10 of the conventional example, light leaks from the reflection region 76 of the signal line 73 that is narrowed to improve crosstalk and the aperture ratio. However, in the present invention, the portion where the signal line 73 becomes thin is on the non-transparent region 78 side. There is no light leakage because it moves.

FIG. 6 is a diagram showing examples of various types of steps. The step may be formed at a right angle as shown in FIG. 6A, may be inclined as shown in FIG. 6B, and the step may be formed at one location as shown in FIG. May be. Further, the two lines that are stepped like the lines P1-P3 and P4-P2 in (d) may not be completely parallel lines.

Thus, by providing a level difference in a single line between P1 and P2 in plan view, a crack generated at P1 is less likely to progress to P2. Thereby, disconnection between P1 and P2 can be prevented.

FIG. 7 is a diagram showing the positions of various boarding lines. Even if the length of the boarding line is the same as that of the connecting portion 87 as shown in FIGS. 7A, 7B, and 7C, the connecting portion 87 can be made difficult to be disconnected by providing a step. When the length of the line is longer than the width of the connecting portion 87 as shown in (d), it is possible to prevent the crack from proceeding from the end portion to the connecting portion by providing a step at the end portion of the line. As shown in (e), the end portion of the reflecting plate 11 extends toward the transmitting region 77 and the direction of the step is provided on the non-transmitting region 78 side, whereby a gap between the reflecting plate 11 and the signal line 73 is formed in the transmitting region 77. 78 and can also prevent light leakage of the backlight. As shown in (f), the step may be provided in the middle of the boarding line.

FIG. 6 is a plan view illustrating a second substrate of a transflective liquid crystal display panel according to an embodiment. It is the top view which gave hatching to the reflecting plate of FIG. It is the top view which gave hatching to the pixel electrode of FIG. FIG. 2 is a plan view in which the auxiliary capacitance and the auxiliary capacitance line in FIG. 1 are hatched. It is AA sectional drawing of FIG. It is a figure which shows the example of the kind of various level | step difference. It is a figure which shows the position of various boarding lines. (A) is a perspective view which shows the schematic structure of the conventional transflective liquid crystal display panel, (b) is the schematic which shows the inclination state of a liquid crystal when an electric field is applied to the liquid crystal of a liquid crystal layer. It is BB sectional drawing of Fig.8 (a). FIG. 6 is a plan view showing a second substrate of a conventional transflective liquid crystal display panel in which a top coat layer for adjusting a cell gap is provided on the second substrate side. It is the top view which gave hatching to the reflecting plate of FIG. It is the top view which gave hatching to the pixel electrode of FIG. It is the top view which gave hatching to the auxiliary capacity and auxiliary capacity line of FIG. It is CC sectional drawing of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display device 10, 50, 70 Transflective liquid crystal display panel 71, 89 Glass substrate 72 Scan line 73 Signal line 74 Inorganic insulating film 75 Protective insulating film 76 Reflection area 77 Transmission area 78 Non-transmission area 79 Interlayer film 80 Contact hole 11, 81 reflector 82 and 82a, _82b, 82b 1, 82b ₂ pixel electrode 83 auxiliary capacitance 84 auxiliary capacitance line 85 intersecting portion 86 slit 87 connecting portion 90 a color filter layer 91 topcoat layer 92 impermeable layer 93 _1, 93 ₂ 94 projection 95 LCD

Claims (1)

A reflection region and a transmission region provided at respective positions partitioned by signal lines and scanning lines arranged in a matrix, and a connecting portion between the pixel electrode of the transmission region and the pixel electrode of the reflection region; A transflective liquid crystal display panel comprising a reflector under the pixel electrode in the reflective region,
Riding the riding pixel electrode in the reflective region is a pixel electrode of the reflective region near the edge of the reflecting plate by covering the edge of the reflecting plate is curved in cross section occurs, the riding is extending in a plan view Extend the line to both sides of the connecting part, provide a step on each ride line,
Providing an impermeable region having an impermeable layer between the transmissive region and the reflective region;
Provided a step of the boarding line near the signal line and on the non-transparent area side,
Transflective liquid crystal display panel.

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