JP3089166B2 - LCD panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display panel suitably used as a display unit in various devices.

[0002]

2. Description of the Related Art A liquid crystal display device can be formed to have a small depth irrespective of the size of a display screen and is light in weight when compared with a display device using a CRT (Cathode Ray Tube) generally used conventionally. It is. Further, since driving at a low voltage is possible, there is an advantage that power consumption can be reduced. However, in a liquid crystal display device, the range of observable viewing angles is significantly limited because liquid crystal molecules have a specific orientation.

[0003] In an operation system of a liquid crystal display panel constituting a liquid crystal display device, for example, a TN (Twisted Nematic) system, an alignment process of a glass substrate is performed by a rubbing method in order to obtain a good display contrast. As the liquid crystal material sealed between the glass substrates, a liquid crystal material having a twist of TN alignment complementary to the vector of the micro-groove structure formed on the substrate surface by the above-described alignment processing is used. In the alignment treatment, the alignment direction of the liquid crystal molecules on the substrate surface is regulated by the rubbing direction, and the twist of the TN alignment is also determined by the liquid crystal material, so that the viewing angle direction in which a good display contrast is obtained is limited. Observation becomes difficult at a viewing angle of, in particular, at a viewing angle that is on the opposite side of the favorable viewing angle direction with respect to a normal to the liquid crystal display panel surface.

[0004] FIG. 10 is a diagram showing the respective viewing angle directions with respect to the liquid crystal display panel 1. The liquid crystal display panel 1 shown in FIG. 10 which can obtain a good display contrast when observed from the first viewing angle direction 2 in which the angle from the normal 3 of the surface of the liquid crystal display panel 1 is the angle θa is the surface of the liquid crystal display panel 1. Observation from the second viewing angle direction 4 at an angle θb that is equal to the angle θa across the normal 3 becomes difficult. Conversely, when the liquid crystal display panel 1 is created so as to obtain a good display contrast when observed from the second viewing direction 4, it becomes difficult to observe the liquid crystal display panel 1 from the first viewing direction 2. . The viewing angle range that can be observed can be expanded by improving the liquid crystal material and alignment processing technology. However, at present, good viewing contrast can be obtained from any viewing angle direction without selecting a viewing angle unlike a CRT. Such a liquid crystal display panel has not been developed.

As described above, the viewing angle of the liquid crystal display panel is limited. Therefore, when manufacturing a liquid crystal display device, it is necessary to match the direction of the good viewing angle of the liquid crystal display panel to be used with the most frequently observed direction. There is. When the liquid crystal display device is created in this manner, it becomes difficult to observe the liquid crystal display panel from a viewing angle direction opposite to a favorable viewing angle direction. ,
A liquid crystal display device using a liquid crystal display panel that can be observed from the opposite viewing angle direction must be created. In other words, it is necessary to prepare two types of liquid crystal display panels: a liquid crystal display panel in which the orientation of liquid crystal molecules with respect to the display screen is processed in one direction and a liquid crystal display panel in which the orientation is processed in the other direction. This is a major problem.

In order to solve the above-mentioned problems, there is a liquid crystal display device having a driving means as described below as another conventional technique. The driving means includes a first driver circuit and a second driver circuit each having a built-in bidirectional shift register, and an inversion control circuit for inverting a moving direction of a signal to each driver circuit. The first driver circuit is connected to, for example, a vertical electrode line in the liquid crystal display panel, and the second driver circuit is connected to, for example, a horizontal electrode line in the liquid crystal display panel. With the above-described configuration, the driving unit can form a normal first display image based on a video signal supplied from the outside to the liquid crystal display panel, and can generate a first display image in the first display image. A second display image can be formed by rotating the first display image by 180 ° about a predetermined point.

When the liquid crystal display device is set at a predetermined position, there is an observation point on the liquid crystal display panel on a side opposite to a good viewing angle direction, and when a good observation state cannot be obtained, the liquid crystal display device itself is moved. 18 around a given point
The display is rotated by 0 ° and the second display image formed by the driving unit is displayed on the liquid crystal display panel. By doing so, the viewing angle direction from the observation point coincides with a favorable viewing angle direction of the liquid crystal display panel.

A technique relating to a display method of a liquid crystal display device is disclosed in Japanese Patent Application Laid-Open No. 1-244494. In the above publication, the display on the display screen is turned upside down and left and right by a changeover switch according to the installation position of the liquid crystal display device, that is, the display is rotated by 180 °, and the liquid crystal display device is mounted upside down to change the viewing angle. In this way, a good display is always obtained. Further, Japanese Patent Application No. 4-342445 filed by the present applicant discloses a positioning means and a posture control means of a liquid crystal display device capable of selecting a favorable viewing angle direction using the liquid crystal display device disclosed in the above publication. As shown, the viewing angle direction of the liquid crystal display device can be selected.

[0009]

In the liquid crystal display device disclosed in the above publication, it is necessary to mount the device body upside down in order to reverse the viewing angle direction. However, the liquid crystal display device is incorporated into another member. For example, in the case of use in a vehicle, another liquid crystal display device in which the viewing angle direction is reversed is required because the device body cannot be rotated. In the case described above, the shape of the liquid crystal display panel differs depending on the direction in which the liquid crystal display device is incorporated. Therefore, even after having a function of inverting the display image, after selecting a favorable viewing angle direction corresponding to the installation position in the liquid crystal display device, The panel periphery must be designed according to the shape according to the installation direction. That is, when it is necessary to reverse the viewing angle direction characteristics when the liquid crystal display device is fixedly used, the peripheral portion of the panel must be designed with the liquid crystal display panel rotated by 180 °. In addition, when two liquid crystal display panels whose viewing angle characteristics are opposite to each other are prepared when a liquid crystal display device is manufactured, the appearance is completely the same, so that when the liquid crystal display panel is incorporated into the liquid crystal display device, they are mixed. There is a problem.

An object of the present invention is to provide a liquid crystal display panel which can be used in common when manufacturing two types of liquid crystal display devices having contradictory viewing angle characteristics without changing the peripheral portion of the panel. is there.

[0011]

SUMMARY OF THE INVENTION The present invention provides a plurality of picture elements arranged in a matrix, a plurality of vertical electrodes for driving the picture elements, and a plurality of horizontal electrodes orthogonal to the vertical electrodes. A plurality of input terminals for supplying drive signals to the vertical electrodes and the horizontal electrodes, respectively, and a liquid crystal display panel in which a viewing angle direction in which a displayed image can be observed with good contrast is determined in a predetermined direction. At
The planar shape of the liquid crystal display panel is a point-symmetric figure, and the input terminals are provided at both ends of the vertical electrode and the horizontal electrode. These four input terminals are point-symmetric with respect to the center of symmetry of the liquid crystal display panel. In a positional relationship, two input terminals, that is, one of the input terminals on one side of the vertical electrode and the input terminal on one side of the horizontal electrode, or three of the four input terminals are connected. A liquid crystal display panel characterized by being used. Further, the invention is characterized in that the shape of the display area formed by arranging a plurality of picture elements is a point-symmetrical figure, and the center of symmetry coincides with the center of symmetry of the liquid crystal display panel. Further, the invention is characterized in that it has identification information for identifying the viewing angle direction.

[0012]

According to the present invention, the liquid crystal display panel is formed such that the viewing angle direction observable with good contrast is a predetermined direction, the plane shape is formed to be point symmetric, and the liquid crystal display panel is formed with respect to the center of symmetry of the liquid crystal display panel. A plurality of input terminals to which a drive signal is supplied to each electrode are provided at both ends so as to be point-symmetric. Therefore, the liquid crystal display panel is 18
Even when the liquid crystal display panel is rotated by 0 ° so that the viewing angle direction at which a good contrast is obtained is on the opposite side to the normal direction of the liquid crystal display panel surface, the plane shape of the liquid crystal display panel and the input terminals Does not change.

Preferably, the shape of the display area formed by arranging a plurality of picture elements in the liquid crystal display panel is point-symmetric with respect to the same point as the center of symmetry of the liquid crystal display panel. It is formed. Therefore, even if the viewing angle direction in the liquid crystal display panel changes by rotating the liquid crystal display panel by 180 °, the shape of the display area does not change.

[0014] More preferably, the liquid crystal display panel is provided with identification information for identifying a viewing angle direction in which a displayed image can be observed with good contrast.
Therefore, even when the planar shape, the input terminal, and the display area of the liquid crystal display panel are all point-symmetrical figures and the centers of symmetry thereof are all coincident, the image on the liquid crystal display panel can be displayed with good contrast. It is possible to instantly identify the viewing angle direction that can be observed.

[0015]

FIG. 1 shows a TFT (Th) according to a first embodiment of the present invention.
FIG. 2 is a plan view of an in-film-transistor type liquid crystal display panel 26, and FIG. 2 is a cross-sectional view taken along line II-II in FIG. The strip-shaped source electrodes S1, S2, S3,..., Sn are parallel to the long side direction of the liquid crystal display panel 26.
(Referred to collectively as a reference S) are formed so as to be parallel and at equal intervals. Similarly, strip-shaped gate electrodes G1, G2, G3, parallel to the short side direction.
.., Gn (the reference numeral G is used when collectively referred to) are formed so as to be parallel and at equal intervals so as to be orthogonal to the source electrode S.

Signal input terminals are provided at both ends of each electrode. On one side of the source electrode S, first source terminals A1, A2,..., An-1, An (referred to collectively as A) are provided, and on the other side, second source terminals B1, B2, ..., Bn-1, B
n (the reference number B is used when collectively referred to).
In the liquid crystal display device 21 described later, a signal is supplied to the source electrode S via one of the first source terminal A and the second source terminal B in synchronization with a horizontal scanning signal supplied to a gate electrode G described later. Supplied.

On one side of the gate electrode G, first gate terminals C1, C2,..., Cm-1, and Cm (the reference numeral C is used when collectively referred to) are provided, and on the other side, a second gate terminal is provided. Terminals D1, D2,..., Dm-1, Dm (the reference numeral D is used when collectively referred to) are provided. In a liquid crystal display device 21 described later, a horizontal scanning signal is supplied to the gate electrode G via one of the first gate terminal C and the second gate terminal D. Each terminal is connected to each driver circuit described later for supplying and driving a signal to a corresponding electrode.

As described above, the liquid crystal display panel 26 is formed such that each terminal is drawn out to both sides of the electrode and is symmetrical with respect to the center O. Further, a display area 28 composed of a plurality of picture elements described later is formed so as to be point-symmetric with respect to the center O. More specifically, each picture element is formed so as to have a point-symmetric positional relationship with respect to the center O. At a corner 26a of the liquid crystal display panel 26, a direction mark 29 indicating a normal viewing angle direction, which is a viewing angle direction in which good display contrast is obtained on the liquid crystal display panel 26, is provided.

In the cross-sectional view of the liquid crystal display panel 26 shown in FIG. 2, the liquid crystal display panel 26 has a pair of first glass substrate 31 and second glass substrate 32, and a peripheral portion of each glass substrate at a predetermined interval. Sealing member 33 to be attached with
And a liquid crystal layer 34 formed by injecting a nematic liquid crystal material into a space surrounded by each glass substrate and the sealing member 33.
It is comprised including. In the nematic liquid crystal in the liquid crystal layer 34, the alignment direction of the liquid crystal molecules is regulated by the rubbing direction of the alignment treatment performed on each glass substrate, and the twist of the nematic liquid crystal is constant. Is limited.

The first glass substrate 31 has pixel electrodes and transistors described later formed in a matrix on one surface 31a. The second glass substrate 32 is provided with a common electrode made of a transparent electrode on one surface 32a. First glass substrate 31
And the second glass substrate 32 each have one surface 31a, 3
2a are bonded so as to face each other.

FIG. 3 is a plan view schematically showing the electrical configuration of the liquid crystal display panel 26. In the liquid crystal display panel 26, a transistor 36 and a picture element electrode 37 are provided in a rectangular region formed by the source electrode S and the gate electrode G, respectively. The liquid crystal display panel 26 has m
× n transistors 36 and picture element electrodes 37 are provided. In each transistor 36, the gate g is connected to the adjacent gate signal line G, the source s is connected to the source signal line S, and the drain d is connected to the pixel electrode 37. Each transistor 36 is operated by a drive signal supplied through the source signal line S and the gate signal line G, and an image is displayed on the liquid crystal display panel 26.

FIG. 4 is a block diagram of the liquid crystal display device 21 including the liquid crystal display panel 26. Liquid crystal display device 21
Is a video signal processing circuit 22 and a control circuit 23
, Source driver circuit 24, and gate driver circuit 2
5 and a liquid crystal display panel 26.

When a video signal processing circuit 22 is supplied with a video signal from the outside, the video signal processing circuit 22 processes the video signal based on a synchronization signal supplied from a control circuit 23 to be described later, and displays a video on a source driver circuit 24. The signal of is supplied. The control circuit 23 supplies a synchronization signal to the video signal processing circuit 22, supplies a clock signal for sampling a signal for displaying a video to the source driver circuit 24, and supplies a scanning signal to the gate driver circuit 25. I do.

The source driver circuit 24 processes the signal for displaying the processed video supplied from the video signal processing circuit 22 in accordance with the clock signal supplied from the control circuit 23, and outputs the source electrode of the liquid crystal display panel 26. The signal is output to S as a signal for driving the liquid crystal. The gate driver circuit 25 is supplied with a scanning signal from the control circuit 23 and outputs a signal for driving a liquid crystal to the gate electrode G of the liquid crystal display panel 26. In the liquid crystal display device 21, each driver circuit and the liquid crystal display panel 26 are connected by TAB (Tape Aut).
It is electrically connected by the omated bonding method.

FIG. 5 shows that the source driver circuits 24a and 24b and the gate driver circuit 25
It is a perspective view showing signs that a and 25b were connected by TAB method. In FIG. 5, the liquid crystal display panel 26 is mounted such that the direction mark 29 indicating the normal viewing angle direction is on the source driver circuit 24 side. Source driver circuit 2
4 is connected to the first source terminal A, and the gate driver circuit 25 is connected to the first gate terminal C.

When the respective driver circuits are mounted as described above, the viewing angle direction in which a good display of the liquid crystal display panel 26 can be obtained depends on the normal line of the surface of the liquid crystal display panel 26 as indicated by the direction mark 29. And a first direction 43 inclined by an angle θa in the direction of an arrow 41 parallel to the short side direction of the liquid crystal display panel 26.

FIG. 6 shows the liquid crystal display panel 26 shown in FIG.
Are rotated by 180 °, and the source driver circuits 24a, 24
FIG. 3B is a perspective view showing a state where the device is connected to the gate driver circuits 25a and 25b. In FIG. 6, the liquid crystal display panel 26 is mounted such that the direction mark 29 indicating the normal viewing angle direction is on the opposite side to the source driver circuit 24. The source driver circuit 24 is connected to the second source terminal B,
Gate driver circuit 25 is connected to second gate terminal D.

When the respective driver circuits are mounted as described above, the viewing angle direction in which a good display of the liquid crystal display panel 26 can be obtained is an arrow θb (= θa) from the normal to the surface of the liquid crystal display panel 26. Arrow 4 opposite to the direction of reference numeral 41
The second direction 44 is inclined in two directions. In the connection examples shown in FIGS. 5 and 6, the position of the display area 28 with respect to the source driver circuit 24 and the gate driver circuit 25 does not change.

As described above, according to the present embodiment, the planar shape is point-symmetric, and the input terminals provided on the peripheral portion also have a point-symmetric positional relationship with respect to the center of symmetry, so that good display contrast can be obtained. By using the liquid crystal display panel 26 in which only one viewing angle direction is possible, two types of viewing angle direction characteristics that are inconsistent with each other without changing the arrangement of the peripheral circuit board that supplies drive signals to the liquid crystal display panel 26. A liquid crystal display device can be manufactured. In addition, since it is not necessary to prepare two types of liquid crystal display panels that are different depending on the required viewing angle direction characteristics, only one type of alignment treatment is required for the alignment film formed on the glass substrate, which greatly reduces the manufacturing process and product management. Cost reduction can be achieved.

For example, even if the vertical and horizontal directions of the liquid crystal display panel 26 are determined so that the viewing angle direction is upward, the vertical and horizontal directions of the liquid crystal display panel 26 are also determined so that the visual angle direction is downward and opposite. Even if you set it,
Since the peripheral circuit boards can be arranged, for example, on the upper side and the left side of the liquid crystal display panel 26, the liquid crystal display panel 2
The positional relationship between 6 and the peripheral circuit board does not change. further,
Since the direction mark 29 indicates the viewing angle direction in which good display contrast is obtained, the liquid crystal display panel 26
Is not incorporated in the liquid crystal display device 21 in a direction opposite to the desired direction.

FIG. 7 is a plan view of a liquid crystal display panel 56 according to a second embodiment of the present invention. In the liquid crystal display panel 56, the same components as those of the liquid crystal display panel 26 described above are denoted by the same reference numerals, and description thereof will be omitted. A feature of the liquid crystal display panel 56 in this embodiment is that input terminals provided on the source electrodes S are alternately drawn to one end and the other end of the liquid crystal display panel 56.

In the liquid crystal display panel 56, one end 5
On the 6a side, first source terminals E1, E connected to source electrodes S1, S3,..., Sn-1 (n is an even number), respectively.
, Eo (o is n / 2; reference numeral E is used when collectively referred to), and connected to source electrodes S2, S4,..., Sn (n is an even number) on the other end 56b side, respectively. , Fo (where o is n / 2:
The reference number F is used for generic terminology). In the liquid crystal display panel 56, the terminals are formed so as to be point-symmetrical, and the center of symmetry is the center O.

FIG. 8 shows that the source driver circuits 54a and 54b and the gate driver circuit 25 are provided on the liquid crystal display panel 56.
It is a perspective view showing signs that a and 25b were connected by TAB method. In the connection example shown in FIG. 8, the liquid crystal display panel 56 is mounted so that the direction mark 29 indicating the normal viewing angle direction is directed in the arrow 41 direction. Source driver circuit 54a
Is connected to the first source terminal E, and the source driver circuit 5
4b is connected to the second source terminal F. The gate driver circuit 25 is connected to the first gate terminal C.

As described above, the liquid crystal display panel 5 when each driver circuit is mounted on the liquid crystal display panel 56
The viewing angle direction in which a favorable display of No. 6 can be obtained is the first direction 43 inclined in the direction of the arrow 41 by an angle θa from the normal to the surface of the liquid crystal display panel 56 as indicated by the direction mark 29.

FIG. 9 shows the liquid crystal display panel 56 shown in FIG.
Are rotated by 180 °, and the source driver circuits 54a, 54
FIG. 4 is a perspective view showing a state where the device is connected to a gate driver circuit and a gate driver circuit. In the connection example shown in FIG. 9, the liquid crystal display panel 56 is mounted so that the direction mark 29 of the liquid crystal display panel 56 faces in the direction of the arrow 42. The source driver circuit 54a
The source driver F is connected to the source terminal F, and the source driver circuit 54b is connected to the first source terminal E. Gate driver circuit 2
5 is connected to the second gate terminal D.

As described above, the liquid crystal display panel 5 when each driver circuit is mounted on the liquid crystal display panel 56
The viewing angle direction in which a good display of No. 6 can be obtained is, as indicated by the direction mark 29, the second direction 44 inclined in the direction of the arrow 42 by the angle θb (= θa) from the normal to the surface of the liquid crystal display panel 56. It is.

As described above, also in this embodiment, the arrangement of the peripheral circuit boards is changed by using the liquid crystal display panel 56 which can obtain a good display contrast in only one direction as in the above-described embodiment. Thus, two types of liquid crystal display devices having opposite viewing angle direction characteristics can be obtained.

The structure of the liquid crystal display panel is as follows.
The present invention is not limited to the structures shown in the first and second embodiments, but has a point-symmetric structure in a liquid crystal display panel.
If the liquid crystal display panel is such that the centers coincide with each other, the same effects as those of the above-described embodiments can be obtained.

The method of driving the liquid crystal display panel has been described in connection with the active matrix method using TFTs. However, even when the liquid crystal display panel is driven by another driving method, the same as in the above-described embodiments. The effect of can be obtained.

[0040]

As described above, according to the present invention, the liquid crystal display panel is formed so that its planar shape is point-symmetric, and each liquid crystal display panel is point-symmetric with respect to the same point as the center of symmetry of the liquid crystal display panel. Since input terminals are formed at both ends of the electrode, the viewing angle direction is one in which good display contrast can be obtained without changing the arrangement of the peripheral circuit board that supplies signals for driving the picture elements of the liquid crystal display panel. By using such a liquid crystal display panel, two types of liquid crystal display devices having opposite viewing angle direction characteristics can be obtained. Further, there is no need to prepare two types of liquid crystal display panels that differ depending on the required viewing angle direction characteristics, and only one type of liquid crystal display panel needs to be prepared for the alignment process, which results in significant costs in the manufacturing process and product management. Down can be planned.

According to the present invention, the display area of the liquid crystal display panel is formed so as to be symmetrical with respect to a point, and the center of the display area is formed so as to coincide with the center of the liquid crystal display panel. The case where the display panel is incorporated into a liquid crystal display device so that a good display contrast can be obtained from one direction, and the case where the display panel is incorporated into a liquid crystal display device so that a good display contrast can be obtained from the other direction. In any of the liquid crystal display devices, since the shape and arrangement of the display region with respect to the liquid crystal display device do not change, it is not necessary to change the appearance of the liquid crystal display device.

Further, according to the present invention, identification information for identifying a viewing angle direction at which a displayed image can be observed with good contrast is provided on the liquid crystal display panel. Even when the terminals and the display area are all point-symmetrical figures and the centers of symmetry are all coincident, the viewing angle direction in which an image on the liquid crystal display panel can be observed with good contrast is instantaneously set. When the liquid crystal display panel is incorporated in the liquid crystal display device, the liquid crystal display device can be manufactured so that the desired viewing angle direction characteristics can be obtained without erroneously assembling the liquid crystal display panel. it can.

[Brief description of the drawings]

FIG. 1 is a liquid crystal display panel 26 according to a first embodiment of the present invention.
FIG.

FIG. 2 is a cross-sectional view taken along the line II-II in FIG.

FIG. 3 is a plan view schematically showing an electrical configuration of the liquid crystal display panel 26.

FIG. 4 is a liquid crystal display device 2 including a liquid crystal display panel 26.
1 is a block diagram.

FIG. 5 is a perspective view showing a state where each driver circuit is connected to the liquid crystal display panel 26.

6 is a perspective view showing a state where the liquid crystal display panel 26 shown in FIG. 5 is rotated by 180 ° and connected to each driver circuit.

FIG. 7 is a liquid crystal display panel 56 according to a second embodiment of the present invention.
FIG.

FIG. 8 is a perspective view showing a state where the liquid crystal display panel 56 and each driver circuit are connected.

9 is a perspective view showing a state in which the liquid crystal display panel 56 shown in FIG. 8 is rotated by 180 ° and connected to each driver circuit.

FIG. 10 is a diagram showing respective viewing angle directions with respect to the liquid crystal display panel 1.

[Explanation of symbols]

 Reference Signs List 21 liquid crystal display device 22 video signal processing circuit 23 control circuit 24 source driver circuit 25 gate driver circuit 26, 56 liquid crystal display panel 28 display area 29 direction mark 31 first glass substrate 32 second glass substrate 33 sealing member 34 liquid crystal layer 36 Transistor 37 Picture element electrode

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1343

Claims (3)

(57) [Claims] 1. A plurality of picture elements arranged in a matrix, a plurality of vertical electrodes for driving the picture elements, a plurality of horizontal electrodes orthogonal to the vertical electrodes, a vertical electrode and a horizontal electrode. A plurality of input terminals each supplying a driving signal to the liquid crystal display panel, wherein a viewing angle direction in which a displayed image can be observed with good contrast is determined in one predetermined direction, and the planar shape of the liquid crystal display panel Is a point symmetrical figure, wherein the input terminals are provided at both ends of a vertical electrode and a horizontal electrode, and these four input terminals are in point symmetry with respect to the center of symmetry of the liquid crystal display panel. Use two input terminals, one of the input terminals on one side of the direction electrode and the input terminal on one side of the horizontal electrode, or use three of the four input terminals. The liquid crystal display panel, characterized in that. 2. The display area formed by arranging a plurality of picture elements is a point-symmetrical figure, and the center of symmetry coincides with the center of symmetry of the liquid crystal display panel. 2. The liquid crystal display panel according to 1. 3. The liquid crystal display panel according to claim 1, further comprising identification information for identifying the viewing angle direction.