JP2003295148A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device having excellent visibility of an alignment mark, capable of easily performing alignment and having a high degree of freedom for design of a liquid crystal display panel. <P>SOLUTION: Dummy terminal forming parts 18 are formed on respective transparent substrates 14 of a plurality of liquid crystal display panels 12, these dummy terminal forming parts 18 are formed in the positions corresponding to terminal forming parts 17 of the mutually adjacent liquid crystal display panels 12 and the alignment marks 19 used for alignment when the panels are laminated are formed at the terminal forming parts 17 and the dummy terminal forming parts 18. <P>COPYRIGHT: (C)2004,JPO

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 device in which two or more liquid crystal display panels are stacked, and in particular,
The present invention relates to a liquid crystal display device provided with alignment marks for alignment when stacking panels.

[0002]

2. Description of the Related Art Generally, a liquid crystal display device for displaying information such as a specific figure or character is often used as a display device for a computer, a mobile phone, etc., and a liquid crystal is used in the middle of this liquid crystal display device. A liquid crystal display panel for displaying information such as specific figures and characters by selectively applying a voltage is built in a predetermined portion of the pair of filled transparent substrates. The liquid crystal used in this liquid crystal display panel includes
A cholesteric phase including a nematic phase, a smectic phase, and a chiral nematic phase obtained by adding a chiral agent to the nematic phase is used.

In some cases, a plurality of liquid crystal display panels are stacked and used in the liquid crystal display device for the purpose of enabling unique display. For example, by stacking multiple liquid crystal display panels each filled with a cholesteric phase whose chiral pitch is adjusted to selectively reflect light in different wavelength regions, light is selectively reflected by the chiral pitch of each cholesteric phase. Thus, multi-color information can be displayed by displaying the light reflected by each liquid crystal display panel or by combining and displaying the light reflected by a plurality of liquid crystal display panels.

A liquid crystal display panel using a chiral nematic liquid crystal, which is a liquid crystal forming a cholesteric phase at room temperature, exhibits selective reflection in the planar state and a fine scattering state in the focal conic state. Then, in order to make a transition to the planar state or the focal conic state, it is sufficient to apply a predetermined voltage and then cut off the voltage. Each state after the voltage is cut off (when no voltage is applied) is maintained until a new voltage is applied. Therefore, this liquid crystal display panel is an element having a memory effect, can reduce power consumption, and can obtain bright reflective display because it is not necessary to use a polarizing plate.

By the way, when a plurality of liquid crystal display panels are laminated, the display colors may be mixed or the display state may be deteriorated unless the display patterns of the respective liquid crystal display panels are precisely aligned and bonded. Therefore, each liquid crystal display panel is formed with an alignment mark used for alignment when the panels are stacked.

For example, in the case of a conventional liquid crystal display device in which two liquid crystal display panels are laminated, that is, a liquid crystal layer has a two-layer structure, a pair of liquid crystal display devices 1 is constructed as shown in FIGS. A pair of alignment marks 3A and 3B are formed on each of the liquid crystal display panels 2A and 2B. These alignment marks 3 (reference numeral 3
Indicates a pair of alignment marks 3A and 3B collectively)
Is a liquid crystal display panel 2 (reference numeral 2 is
The liquid crystal display panels 2A and 2B are collectively referred to as “two liquid crystal display panels 2A and 2B”). There is. In addition, these alignment marks 3
Is a transparent conductive film made of indium tin oxide (ITO) or the like formed on the inner surface of each of the pair of transparent substrates 4 forming a part of each liquid crystal display panel 2, similar to a display electrode (not shown). Is formed by an electrode obtained by patterning a photolithographic method or the like into a predetermined pattern. Then, on the surface of the electrode, an alignment film made of a polymer such as polyimide whose surface is subjected to a rubbing treatment in order to arrange liquid crystal molecules in a constant form between the electrodes facing each other is formed. The alignment mark 3
One end of each lead terminal 5 formed on the terminal forming portion 4a of each transparent substrate 4 is electrically connected to the. Further, the terminal forming portions 4a of each transparent substrate 4 are arranged in four directions so that connection wirings (not shown) used for supplying electric power and signals do not interfere with each other. That is, in the liquid crystal display panel 2A located on the lower side of FIG. 7, the terminal formation portion 4a is formed on the upper side of FIG. 10 of the transparent substrate 4 located on the lower side and the left side of FIG. 10 of the transparent substrate 4 located on the upper side. In the liquid crystal display panel 2B located above in FIG. 7, the terminal forming portion 4a is formed on the lower side of the transparent substrate 4 located below in FIG. 11 and the right side of the transparent substrate 4 located above in FIG. Are formed. In addition, between the facing surfaces of the two liquid crystal display panels 2A and 2B facing each other, a material such as an epoxy resin or an acrylic resin and having fluidity such as a thermosetting resin or a photocurable resin is used. It is adhered by an adhesive agent (not shown).

The two liquid crystal display panels 2A and 2B
When stacking panels, align the lead terminals 5
While the alignment mark 3 is turned on by externally supplying electric power such as by attaching a conductive tape to the alignment mark 3, the alignment mark 3 is recognized by an image recognition device such as a CCD camera of the alignment device. Turning on the alignment mark 3 here means that in the case of a liquid crystal layer using a chiral nematic liquid crystal,
By applying a voltage to bring the liquid crystal into a homeotropic state, the liquid crystal layer at the position where the alignment mark 3 is formed is made transparent.

As the alignment mark 3, there is also a configuration in which pixels located at two corners located at both ends on the diagonal of the square of the display area are used.

[0009]

In the liquid crystal display device 1 in which a plurality of conventional liquid crystal display panels 2 described above are stacked, the alignment mark 3 is formed inside the liquid crystal display panel 2. When the thickness of the transparent substrate 4 is increased according to the specifications, the visibility of the alignment mark 3 is reduced even if the alignment mark 3 is turned on.
There are problems that the time required for the alignment is increased, and the alignment accuracy is reduced to lower the yield.

Further, in the conventional liquid crystal display device 1,
Since it is necessary to turn on the alignment mark 3 on the alignment device, a work of attaching a conductive tape to each lead terminal 5 and a work of connecting a wire for power supply to the conductive tape are required as a preparation for alignment. However, there is a problem that the productivity is poor and the manufacturing cost is increased.

Further, in the conventional liquid crystal display device 1, the alignment mark 3 may not be formed inside the liquid crystal display panel 2 in which the liquid crystal is held, depending on the specifications such as when the non-display area is small. There was also a problem. That is, there is a problem that the degree of freedom in designing the liquid crystal display panel 2 is small.

The present invention has been made in view of these points, and the liquid crystal display is excellent in the visibility of the alignment marks, can be easily aligned, and has a high degree of freedom in the design of the liquid crystal display panel. The purpose is to provide a device.

[0013]

In order to achieve the above-mentioned object, the liquid crystal display device according to the present invention according to claim 1 is characterized in that a plurality of liquid crystal display panels are laminated. A dummy terminal forming portion is formed on each of the transparent substrates of the plurality of liquid crystal display panels, and these dummy terminal forming portions are formed at positions corresponding to the terminal forming portions of the liquid crystal display panels adjacent to each other. In addition, the terminal formation portion and the dummy terminal formation portion are provided with alignment marks used for alignment when the panels are stacked. By adopting such a configuration, since the alignment mark is formed on the external terminal forming portion and the dummy terminal forming portion where the liquid crystal is not held, the alignment mark itself can be directly or externally applied to the transparent substrate. It can be easily seen through. Further, since the alignment mark itself can be easily visually recognized from the outside directly or through the transparent substrate, the alignment at the time of stacking the panels can be easily performed as it is. Furthermore, since the alignment mark can be formed regardless of the specifications such as when the non-display area is small, the degree of freedom in designing the liquid crystal display panel is increased.

The feature of the liquid crystal display device of the present invention according to claim 2 is that in the liquid crystal display device according to claim 1,
The alignment mark is formed of the same material as the electrode. By adopting such a configuration, the alignment mark can be formed at the same time as the electrode.

The liquid crystal display device according to a third aspect of the present invention is characterized in that, in the liquid crystal display device according to the first or second aspect, a chiral nematic liquid crystal exhibiting different selective reflection colors in each liquid crystal display panel. Is the point that is enclosed. By adopting such a configuration, multi-color display can be easily performed.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described below with reference to the embodiments shown in the drawings.

1 to 5 show an embodiment of a liquid crystal display device according to the present invention. FIG. 1 is a front view showing a main part of the entire structure, FIG. 2 is a right side view of FIG. 1, and FIG. 1 is a plan view of FIG. 1, FIG. 4 is a plan view of a first liquid crystal display panel, and FIG. 5 is a plan view of a second liquid crystal display panel.

The liquid crystal display device of this embodiment exemplifies a structure in which two liquid crystal display panels are laminated and the liquid crystal layer has a two-layer structure.

As shown in FIGS. 1 to 3, the liquid crystal display device 11 of this embodiment is a first liquid crystal display panel 12A shown in the lower part of FIG. 1, and is laminated on the first liquid crystal display panel 12A. It has two liquid crystal display panels 12 including the second liquid crystal display panel 12B (reference numeral 12 is a general term for the first liquid crystal display panel 12A and the second liquid crystal display panel 12B). The first liquid crystal display panel 12A and the second liquid crystal display panel 12B are laminated by being overlapped so as to face each other. These two liquid crystal display panels 12
In the usage state, one is arranged on the most upstream side in the viewing direction, which is the observation side, and the other is arranged on the most downstream side in the viewing direction. Further, a black light absorber (not shown) is arranged on the opposite side (back surface side) of the transparent substrate 14Aa below the first liquid crystal display panel 12A arranged on the most downstream side in the viewing direction.

The first liquid crystal display panel 12A and the second liquid crystal display panel 12A
The liquid crystal display panel 12B includes a pair of transparent substrates 14 arranged substantially parallel to each other and facing each other.
have. Electrodes and alignment films obtained by patterning a transparent conductive film (not shown) made of indium tin oxide or the like into a predetermined pattern by photolithography or the like are laminated on the inner surfaces of the transparent substrates 14 which face each other. . The cell gaps of the respective transparent substrates 14 are maintained at about several μm by spacers (not shown), and the respective transparent substrates 14 are
Are integrally formed by being bonded together by a sealing material (not shown) which also serves as an adhesive and which is arranged in a substantially rectangular frame shape in the peripheral portion between the facing surfaces of the respective transparent substrates 14. In the region surrounded by the sealant, a liquid crystal layer is formed by enclosing chiral nematic liquid crystal which is a cholesteric phase exhibiting different selective reflection colors for performing multicolor display.

The first liquid crystal display panel 12A of the present embodiment is filled with a chiral nematic liquid crystal having a main selective reflection wavelength of 450 nm, and the second liquid crystal display panel 12B is provided with a chiral nematic liquid crystal having a main selective reflection wavelength of 570 nm. Liquid crystal is enclosed.

Therefore, the liquid crystal display device 1 of the present embodiment
In No. 1, multicolor display of a total of four colors of blue, orange, white and black is formed.

The display color of the liquid crystal display device 11 is
It may be set according to the purpose of use, design concept, etc.

A display electrode (not shown) having a predetermined pattern made of an electrode is provided inside the portion of each transparent substrate 14 surrounded by the sealing material. As shown in FIG. An area in which pixels used for displaying information are formed inside a portion of the transparent substrate 14 surrounded by the sealing material is a display area used for displaying information. The outside of the display area is a non-display area that does not participate in the display of information.

As shown in FIG. 4, the first liquid crystal display panel 1
The transparent substrate 14 shown below among the transparent substrates 14 of 2A.
The edge of Aa located on the upper side of FIG. 4 is formed so as to project from the edge of the transparent substrate 14Ab shown above.
The upper surface of this projecting portion has a large number of electrode terminals 1 made up of electrodes used for supplying electric power and signals to the display electrodes.
6, for example, a terminal forming portion 17A in which common electrodes are aligned
It is a. In addition, among the transparent substrates 14 of the first liquid crystal display panel 12A, the edge of the transparent substrate 14Ab shown above that is located on the left side of FIG. 4 is the transparent substrate 14A shown below.
It is formed so as to project from the edge of a, and the lower surface of this projecting portion has a large number of electrode terminals 16 made of electrodes used for supplying power and signals to the display electrodes, for example, segment electrodes arranged in an array. Terminal forming portion 17Ab
Has become. The edge of the transparent substrate 14Ab located on the lower side of FIG. 4 is formed on the lower side of FIG. 5 of the transparent substrate 14Ba arranged below the second liquid crystal display panel 12B which is a liquid crystal display panel adjacent to each other. The dummy terminal forming portion 18Ba is formed so as to overlap the formed terminal forming portion 17Ba, and the lower surface of the protruding portion serves as a dummy terminal forming portion 18A. That is, the dummy terminal formation portion 18A of the first liquid crystal display panel 12A is formed at a position corresponding to the terminal formation portion 17Ba of the second liquid crystal display panel 12B which is the liquid crystal display panel 12 adjacent to each other.

Alignment marks 19A made of the same material as the electrodes are provided in the vicinity of the upper end of FIG. 4 of the terminal forming portion 17Ab of the first liquid crystal display panel 12A and in the vicinity of the right end of the dummy terminal forming portion 18A in FIG. Has been formed. These alignment marks 19A are formed at the same time when electrodes are formed by patterning a transparent conductive film made of ITO or the like formed on the inner surfaces of the pair of transparent substrates 14Aa and 14Ab into a predetermined pattern by photolithography or the like. Has been done.

As shown in FIG. 5, the second liquid crystal display panel 1
The transparent substrate 14 shown below among the transparent substrates 14 of 2B.
The edge of Ba located at the lower side of FIG. 5 is formed so as to project from the edge of the transparent substrate 14Bb shown above.
The upper surface of this projecting portion has a large number of electrode terminals 1 made up of electrodes used for supplying electric power and signals to the display electrodes.
6, for example, a terminal forming portion 17B in which common electrodes are aligned
It is a. In addition, among the transparent substrates 14 of the second liquid crystal display panel 12B, the edge of the transparent substrate 14Bb shown above located on the right side of FIG. 5 is the transparent substrate 14B shown below.
It is formed so as to project from the edge of a, and the lower surface of this projecting portion has a large number of electrode terminals 16 made of electrodes used for supplying power and signals to the display electrodes, for example, segment electrodes arranged in an array. Terminal forming portion 17Bb
Has become. The edge of the transparent substrate 14Ba located on the left side in FIG. 5 is formed on the left side in FIG. 4 of the transparent substrate 14Ab arranged above the first liquid crystal display panel 12A which is a liquid crystal display panel adjacent to each other. The dummy terminal forming portion 18B is formed so as to overlap the formed terminal forming portion 17Ab, and the upper surface of the protruding portion serves as a dummy terminal forming portion 18B. That is, the dummy terminal formation portion 18B of the second liquid crystal display panel 12B is formed at a position corresponding to the terminal formation portion 17Ab of the first liquid crystal display panel 12A which is a liquid crystal display panel adjacent to each other.

Therefore, the liquid crystal display device 1 of the present embodiment
1, the terminal forming portion 17 (reference numeral 17 is a general term for the four terminal forming portions 17Aa, 17Ab, 17Ba, 17Bb) is formed to extend in four directions of up, down, left and right.

The first of the second liquid crystal display panel 12B
Electrodes are provided near the right end of FIG. 5 of the terminal forming portion 17Ba of the second liquid crystal display panel 12B, which is a position facing the alignment mark 19A of the liquid crystal display panel 12A, and near the upper end of the dummy terminal forming portion 18B of FIG. An alignment mark 19B made of the same material is formed. Similar to the alignment mark 19A of the first liquid crystal display panel 12A, these alignment marks 19B are formed by a transparent conductive film made of ITO or the like formed on the inner surfaces of the pair of transparent substrates 14Ba and 14Bb by a photolithography method or the like. The electrodes are formed at the same time as the electrodes are formed by patterning into a predetermined pattern.

Therefore, the liquid crystal display device 1 of the present embodiment
1 alignment mark 19 (reference numeral 19 indicates the alignment mark 19A and the second alignment mark 19A of the first liquid crystal display panel 12A).
The alignment marks 19B of the liquid crystal display panel 12B are collectively referred to as “alignment marks 19B” are arranged on both ends of the liquid crystal display device 11 on a substantially diagonal plane.

The alignment mark 19 can be selected from various conventionally known ones. An example of such an alignment mark 19 is shown in FIGS.
The alignment mark 19 may be a cutting line mark or the like.

The alignment mark 19 is TAB.
It may also serve as a connection wiring used for alignment with a connection wiring substrate (not shown) such as a substrate.

The surface of the alignment mark 19 may be colored depending on the design concept or the like.

Further, the alignment mark 19 may be independently formed of a material different from the electrode such as a colored layer made of the same material as the light absorption layer.

Between the facing surfaces of the two liquid crystal display panels 12 facing each other, a material such as an epoxy resin or an acrylic resin, which has fluidity, such as a thermosetting resin or a photocurable resin is used. It is adhered by an adhesive agent (not shown).

Next, the operation of this embodiment having the above-mentioned structure will be described.

According to the liquid crystal display device 11 of this embodiment,
The external terminal forming portion 17 and the dummy terminal forming portion 18 not holding the liquid crystal (reference numeral 18 indicates the dummy terminal forming portion 18A of the first liquid crystal display panel 12A and the dummy terminal forming portion 18B of the second liquid crystal display panel 12B). Generic name)
Since the alignment mark 19 is formed on the alignment mark 19, the alignment mark 19 itself can be easily visually recognized from the outside directly or through the transparent substrate.

That is, the liquid crystal display device 11 of the present embodiment.
Since the alignment mark 19 of is excellent in visibility,
Unlike the conventional alignment mark 3, it is not necessary to turn it on.

Further, according to the liquid crystal display device 11 of the present embodiment, the alignment mark 19 itself can be easily visually recognized from the outside directly or through the transparent substrate 14, and therefore, the first liquid crystal display panel at the time of stacking the panels. 12A and second
The mutual alignment with the liquid crystal display panel 12B can be easily performed as it is.

That is, the liquid crystal display device 11 of the present embodiment.
When the panel is laminated, the alignment mark 3 is lit when the panel of the conventional liquid crystal display device 1 is laminated, the work of attaching the conductive tape to each lead terminal 5 for lighting the alignment mark 3, and the power supply to the conductive tape. Since you can omit the work of connecting the wiring of
It is possible to easily improve productivity and reduce manufacturing cost.

Further, according to the liquid crystal display device 11 of the present embodiment, the external terminal forming portion 1 in which liquid crystal is not held is provided.
7 and the dummy terminal forming portion 18 on the alignment mark 1
Since the alignment marks 19 are formed, the alignment marks 19 can be easily formed regardless of the specifications such as when the non-display area is small, so that the degree of freedom in designing the liquid crystal display panel 12 is increased.

Therefore, the liquid crystal display device 1 of the present embodiment
In No. 1, the alignment mark 19 has excellent visibility, the alignment can be easily performed, and the degree of freedom in designing the liquid crystal display panel 12 is large.

Further, according to the liquid crystal display device 11 of this embodiment, since the alignment mark 19 is made of the same material as the electrode, the alignment mark 19 can be formed at the same time as the electrode.

Furthermore, according to the liquid crystal display device 11 of the present embodiment, since the liquid crystal display panel 12 is filled with the chiral nematic liquid crystal exhibiting different selective reflection colors, multi-color display can be easily performed. .

In the present invention, it is possible to stack three or more liquid crystal display panels. In this case, three or more liquid crystal display panels can be stacked in a single stacking step, and the stacking time can be shortened. Further, it is also possible to first stack two liquid crystal display panels and then stack the two stacked liquid crystal display panels and another liquid crystal display panel. In this case, each liquid crystal display panel can be easily aligned and the stacking process can be facilitated.

Further, the present invention is not limited to the above-mentioned embodiment, but can be variously modified if necessary.

[0047]

As described above, according to the liquid crystal display device of the present invention according to the first aspect, the alignment marks are excellent in the visibility, the alignment can be easily performed, and the design of the liquid crystal display panel is made. It has an extremely excellent effect such as a high degree of freedom.

Further, according to the liquid crystal display device of the present invention according to the second aspect, there is an extremely excellent effect that the alignment mark can be formed at the same time as the electrode.

Further, according to the liquid crystal display device of the present invention according to the third aspect, it is possible to achieve an extremely excellent effect such as easy multi-color display.

[Brief description of drawings]

FIG. 1 is a front view showing a main part of an overall configuration of an embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a right side view of FIG.

FIG. 3 is a plan view of FIG.

FIG. 4 is a plan view of a first liquid crystal display panel of the liquid crystal display device of FIG.

5 is a plan view of a second liquid crystal display panel of the liquid crystal display device of FIG.

6A to 6C are plan views showing various forms of alignment marks.

FIG. 7 is a front view showing a main part of the overall configuration of a conventional liquid crystal display device.

8 is a right side view of FIG.

9 is a plan view of FIG.

10 is a plan view of a first liquid crystal display panel of the liquid crystal display device of FIG.

11 is a plan view of a second liquid crystal display panel of the liquid crystal display device of FIG.

[Explanation of symbols]

11 liquid crystal display device 12 liquid crystal display panel 12A first liquid crystal display panel 12B second liquid crystal display panel 14, 14Aa, 14Ab, 14Ba, 14Bb transparent substrate 16 electrode terminals 17, 17Aa, 17Ab, 17Ba, 17Bb terminal forming portions 18, 18A, 18B Dummy terminal forming portion 19, 19A 19B Alignment mark

Claims (3)

[Claims] 1. A liquid crystal display device in which a plurality of liquid crystal display panels are stacked, wherein dummy terminal formation portions are formed on each of the transparent substrates of the plurality of liquid crystal display panels, and the dummy terminal formation portions are formed. It is formed at a position corresponding to the terminal formation portion of the liquid crystal display panel adjacent to each other, and the terminal formation portion and the dummy terminal formation portion are formed with alignment marks used for alignment during panel stacking. Characteristic liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein the alignment mark is formed of the same material as the electrode. 3. The liquid crystal display device according to claim 1, wherein each of said liquid crystal display panels is filled with a chiral nematic liquid crystal exhibiting a different selective reflection color.