KR100900129B1 - Liquid crystal display element - Google Patents

Abstract

An eight-shaped segment block 61 composed of seven segments 63 is connected to an adjacent segment block 61 by a liquid crystal injection path 62 having a key S-shaped structure. Inside the segment block 61, two sets of left and right opposing segments 63 on the upper side and the lower side are connected to the liquid crystal injection path 64 of a key S-shaped structure, and the upper, middle and lower three segments ( 63 is connected with the liquid crystal injection path 64 by the liquid crystal injection path 65 of the linear structure which splits in the longitudinal direction from the liquid crystal injection path 64.

Liquid crystal injection hole, strut, segment, wall structure, liquid crystal display element

Description

Liquid crystal display element {LIQUID CRYSTAL DISPLAY ELEMENT}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device using a cholesteric liquid crystal (cholesteric liquid crystal) whose molecular orientation state is a liquid crystal material, and particularly relates to a liquid crystal display device having excellent physical durability.

In recent years, RFID (Radio Frequency Identification) such as a non-contact type IC card and an RF tag having durability and convenience has begun to spread in industries such as logistics where contact type IC cards, bar codes and the like are used. In the future, new application fields such as electronic money will also be pioneered, and cards and tags that perform wireless communication with external devices are expected to become increasingly popular.

Although the IC card has excellent information recording, there is a problem that the IC card cannot be confirmed until the contents of the recording are read by a dedicated device. This is because it is expected that the record contents can be visually recognized by the coupon card used in the point card or the transportation field. In the conventional contact type IC card, a display using magnetic flakes, a display using a medium that can be seen by thermal writing using a leuco dye, and the like have been proposed. Such a contact type IC card requires a dedicated device into which the IC card is inserted, and a display writing device having a magnetic head or a column head is incorporated in the dedicated device. However, in the non-contact type IC card and RF tag which are expected to spread in the future, it is not possible to mount the writing head which the dedicated device for a contact type IC card has. For this reason, it is necessary to display using an electric signal supplied wirelessly, and display by the liquid crystal system, electrophoresis system, etc. which can be electrically driven is required.

As a literature concerning an IC card and an RF tag provided with a display element, there is a patent document 1 and a patent document 2 filed with the following Japanese Patent Office.

Patent Document 1: Japanese Unexamined Patent Publication No. 7-30384

Patent Document 2: Japanese Patent Application Laid-Open No. 2002-236891

In the third column, the sixth column and the 37th line of Patent Document 1, there is a description that assumes a non-contact type IC card or RF tag. The structure of the non-contact type IC card is described in detail in Patent Document 2. In patent document 1 and patent document 2, a liquid crystal display element is proposed as one candidate of a display element. When using a liquid crystal display element as a display element of a non-contact type IC card, as a candidate of the liquid crystal material, the ferroelectric liquid crystal and cholesteric liquid crystal which hold | maintain a display even if a power supply is cut | disconnected are assumed. The cholesteric liquid crystal is sometimes called chiral nematic liquid crystal.

Conventionally, the reason why the liquid crystal display element has not been realized as a display element of an IC card or an RF tag has been its physical durability. This is because the IC card cannot be used as an element unless the conditions such as bending resistance, environmental test, etc., which are standardized in JIS, are satisfied, and in general liquid crystal display elements, these conditions cannot be satisfied.

For example, in the IC card, when the long side of the main body is 85 mm, it is required that the IC card not be broken even if the endurance test of repeating the operation of bending the center 2 cm is performed 500 times or more. In the conventional liquid crystal display element, the endurance test could not be satisfied due to breakage of the substrate, disturbance of the alignment of the liquid crystal molecules, peeling off of the actual substance, and the like.

In an IC card of contact type or hybrid type (type having both functions of contact and non-contact), a strong pressure (roller pressure) is applied to the surface of the card from the conveying roller when inserted into the reading apparatus. In a conventional liquid crystal display element, the liquid crystal is biased in one direction by this roller pressure, a seal is broken at the edge portion, the liquid crystal leaks, and the function as the liquid crystal display element is lost.

Therefore, the applicant of Patent Document 3 (Japanese Patent Application Laid-Open No. 15-998646) discloses a thin element structure using a cholesteric liquid crystal that can satisfy the JIS standard and can also be mounted on an IC card having a standard thickness (0.76 mm). A liquid crystal display device is proposed. By the way, patent document 4 (Unexamined-Japanese-Patent No. 2002-328374) proposes the structure of the liquid crystal display element which improved durability using antiferroelectric liquid crystal. However, semiferroelectric liquid crystals cannot be applied to IC cards because, in principle, alignment is difficult to maintain and the impact resistance is weak. In addition, since it is necessary to use a polarizing plate, it is difficult to mount a standard thickness (0.76 mm) onto an IC card.

Although the liquid crystal display element proposed by the said patent document 3 was able to satisfy | fill durability of the JIS standard, it also could not solve a problem. This problem is a problem that the cholesteric liquid crystal has, and the force applied to the cholesteric liquid crystal by bending or twisting the liquid crystal display element by an operation such as pressing or holding the display surface of the liquid crystal display element with a finger. This is a problem that the display state changes. It is also known that the cholesteric liquid crystal has a property of returning to its original state by performing display driving again.

Considering the practical use of the IC card, it is a big problem that the display of the IC card changes to the force (pressure pressure) of the finger. Even if the display state can be restored by re-drive, it is not convenient for the user. It becomes. The present applicant tried an empirical test with respect to the liquid crystal display element of patent document 3. As shown in FIG. As a result, in the structure of this liquid crystal display element, it turned out that a display changes with the pressure pressure (acupressure) of a finger.

1 is a schematic view showing the entire structure of a liquid crystal display element proposed in Patent Document 3, and FIG. 2 is an exploded view of the liquid crystal display element. 3 is a sectional view of the wall surface structure (wall surface material) provided in the liquid crystal display element and the horizontal direction of the display part. 4 is a figure which shows a part of cross section in the direction parallel to the layer containing the liquid crystal cell and partition of the liquid crystal display element disclosed by patent document 4. As shown in FIG.

The liquid crystal display element proposed in Patent Document 3 has a structure in which a wall structure 3, a display portion 4, a light shielding mask 5, and the like are sandwiched between a segment substrate 1 and a common substrate 2. have.

As shown in FIG. 2, the wall surface structure 3 and the display portion 4 are provided between the common substrate 2 and the light shielding mask 5. The thickness of the layer which has this wall surface structure 3 and the display part 4 is several micrometers. In the example of FIG. 2, the display part 4 is comprised from four segment blocks 4a. Hereinafter, for convenience, the layer having the wall surface structure 3 and the display portion 4 will be referred to as the liquid crystal cell layer 10.

The liquid crystal cell layer 10 has a liquid crystal injection path 11 and a buffer part 12 in addition to the wall structure 3 and the display part 4 strictly. The liquid crystal injection path 11 is a passage provided for injecting liquid crystal into the display portion 4 which is a liquid crystal cell, and is provided between the adjacent segment blocks 4a on the left side of the first segment block 4a. The shape of this liquid crystal injection path 11 is a straight line. Injection of the liquid crystal in the liquid crystal cell layer 10 is made from the left end 11a of the liquid crystal injection path 11 connected to the left end of the segment block 4a at the first stage. The injected liquid crystal is injected into the segment block 4a of the last stage through the liquid crystal injection path 11 and the segment block 4a. The buffer part 12 connected to the right end of the segment block 4a of the last stage is provided in order to seal the excess air which flows in when vacuum-injecting a liquid crystal. Due to the structure, the liquid crystal is also injected into the buffer unit 12.

A light shielding mask (light shielding film) 5 is provided on the wall structure 3. The light shielding mask 5 is a mask for preventing the liquid crystal injection region (the liquid crystal injection path 11 and the buffer portion 12) unnecessary as segment display in the liquid crystal cell layer 10 from functioning as a display region. It is formed on (1). The light shielding mask 5 has the light transmission part 5a of the shape corresponding to the segment pattern of the display part 4. The width of the light transmitting portion 5a is smaller than the width of the segment block 4a of the display portion 4 in consideration of alignment margin and visibility. By the light shielding action of this light shielding mask 5, the display part 4 can perform segment display excellent in visibility and contrast.

4 is a horizontal cross-sectional view of the liquid crystal layer of the liquid crystal display device proposed in Patent Document 4. FIG. In the same figure, the white portion is the display portion (segment) 20 or the liquid crystal injection path 28 corresponding to the portion where the liquid crystal cell is installed. In patent document 4, each segment is represented by the display part (or liquid crystal cell). The liquid crystal injection path 28 is shown by six parallel thin lines, and the display part 20 is shown by the square which is thicker than the thin line, or is substantially square. The left end of the liquid crystal injection path 28 is a liquid crystal injection unit 29. The anti-ferroelectric liquid crystal is injected into the display unit 20 through the liquid crystal injection unit 29 and the liquid crystal injection path 28. In addition, the blackened part becomes the partition 27.

As described above, the liquid crystal display device of Patent Document 3 and the liquid crystal display device of Patent Document 4 are both similar in structure, and the main difference in configuration between the liquid crystal display device of Patent Document 3 and the liquid crystal display device of Patent Document 4 is The liquid crystal materials used are different from each other. The cholesteric liquid crystal is used in the liquid crystal display element of patent document 3, and the semiferroelectric liquid crystal is used in the liquid crystal display device of patent document 4.

In any of the above-mentioned liquid crystal display element of patent document 3 and the liquid crystal display device of patent document 4, there exists a problem that a display state changes by the pressure on the display surface, the bending of an element (apparatus), etc ..

<Start of invention>

A first object of the present invention is to provide a cholesteric liquid crystal display device capable of preventing a change in display state even when the display surface is pressed with a finger, a pen tip, or the like. A second object of the present invention is to provide a cholesteric liquid crystal display device capable of preventing a change in the display state even when the device is bent or twisted.

The 1st aspect of the liquid crystal display element of this invention is between the board | substrate which opposes, the wall surface structure provided between these board | substrates, the some segment block comprised from the some segment by which the side wall was surrounded by the wall structure, and the segment block. It is assumed that a liquid crystal display device using a cholesteric liquid crystal having a liquid crystal injection path surrounded by a side surface of the wall structure to be connected. A plurality of segment blocks comprising at least one segment connected to only one liquid crystal injection path of the liquid crystal is provided.

As described above, by providing at least one segment of the liquid crystal having no outlet in each segment block, it becomes possible to improve the resistance in the equally distributed load given from the outside and to press the display surface with a finger or the like. The change of the display state can be prevented.

The liquid crystal display device of the second aspect of the present invention is characterized in that, in the liquid crystal display element of the first aspect, a support for holding the opposing substrate is provided inside the segment.

In this way, by installing the support in the inside of the segment, it becomes possible to improve the resistance of the segment to the concentrated load applied from the outside, and even if the surface is pressed with a sharp tip such as the tip of a pen or a fingernail, the display of the segment changes. Can be prevented.

The liquid crystal display element of the 3rd aspect of this invention is a cholesteric liquid crystal which has a board | substrate which opposes, the wall surface structure provided between these board | substrates, and the some segment block comprised from the some side surface surrounded by the wall surface structure. Assuming that the liquid crystal display element used is used, each segment block is not connected to another segment block.

Thus, since each segment is connected by the flow path of a liquid crystal, resistance to the equal distribution load given from the exterior can be improved more than the liquid crystal display element of a said 1st aspect.

The liquid crystal display element of the 4th aspect of this invention is characterized in that the support | pillar holding the said opposing board | substrate is provided in the said segment in the liquid crystal display element of the said 3rd aspect, It is characterized by the above-mentioned.

Thus, by providing a support | pillar in a segment, resistance of a segment with respect to the concentrated load applied from the outside can be improved by the effect similar to the liquid crystal display element of a said 2nd aspect, and it concentrates on a part of surface. Even if this is applied, the display change of the segment can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the whole structure of the conventional cholesteric liquid crystal display element.

2 is an exploded view showing a main part of the conventional cholesteric liquid crystal display element.

3 is a horizontal sectional view of a liquid crystal cell layer in the conventional cholesteric liquid crystal display device.

4 is a horizontal cross-sectional view of a liquid crystal cell layer in a conventional antiferroelectric liquid crystal display device.

Fig. 5 is a diagram showing a portion of change of the display state due to the pressing of the conventional liquid crystal cell layer.

FIG. 6 is a view showing a portion of change in display state due to pressing of a liquid crystal cell layer having another conventional structure. FIG.

FIG. 7 is a diagram showing a load-bearing effect in the liquid crystal display of each embodiment of the present invention. FIG.

8 is a horizontal sectional view of the liquid crystal cell layer in the liquid crystal display element of Example 1;

9 is a diagram showing a manufacturing process of a liquid crystal display element of Example 1;

10 is a horizontal sectional view of the liquid crystal cell layer in the liquid crystal display element of Example 2;

11 is a horizontal sectional view of the liquid crystal cell layer in the liquid crystal display element of Example 3;

12 is a diagram showing a state of deformation of a segment when a concentrated load is applied to the segment.

Fig. 13 is a three-dimensional perspective view showing the structure of a segment in the liquid crystal display element of Example 4;

Fig. 14 is a horizontal sectional view of a segment in the liquid crystal display element of Example 4;

15 is a vertical sectional view of the liquid crystal display device of Example 4;

Fig. 16 is a horizontal sectional view of a segment in the liquid crystal display element of Example 5;

17 is a horizontal sectional view of a segment in the liquid crystal display element of Example 6;

18 is a horizontal sectional view of a segment in the liquid crystal display element of Example 7;

19 is a horizontal sectional view of a segment in the liquid crystal display element of Example 8;

<Best Mode for Carrying Out the Invention>

As shown in Patent Literature 3, the mechanism by which the display state of the cholesteric liquid crystal display element changes due to the pressure applied to the display surface was investigated in the experiment. This mechanism will be described with reference to FIGS. 5 and 6.

5 and 6 show a top view of the wall surface structure, wherein the wall surface structure shown in FIG. 5 and the wall surface structure shown in FIG. 6 are different in shape.

In the wall structure 30 shown in FIG. 5, four segments 31 having an eight-shape are connected by a linear liquid crystal injection path 32. The left end center of the first segment 31, 31-1 is connected to the liquid crystal injection paths 32 and 32-1, and the left end of the liquid crystal injection path 32-1 is the liquid crystal injection hole 34. It is. Moreover, the linear air seal part 33 is connected to the center of the right edge of the segment 31 and 31-4 of the last stage.

In the wall structure 40 shown in FIG. 6, four segments 41 are connected by a liquid crystal injection path 42 in a zigzag shape. The center portions of the upper half are between the first and second stage segments 41, and the center portions of the lower half are between the second and third segments 41 and the segments 41 of the third and fourth stages. The upper half center parts are connected by the linear liquid crystal injection path 42 between them.

[Experiment 1]

A cholesteric liquid crystal was injected into the wall surface structure 30 shown in FIG. 5 from the liquid crystal injection path 32-1 to produce a cholesteric liquid crystal display element (not shown) of the film substrate. When the display surface of this cholesteric liquid crystal display element was pressed with a finger, the display state of the part shown by the broken line pattern 36 of FIG. 5 changed easily. In addition, when the cholesteric liquid crystal display element was bent in the longitudinal direction and bent, the display state was easily changed at the portion where the dashed line pattern 36 on the display surface appeared in the same manner as when the finger was pressed.

[Experiment 2]

A cholesteric liquid crystal was injected into the wall structure 40 shown in FIG. 6 from the liquid crystal injection paths 42 and 42-1 to produce a cholesteric liquid crystal display element (not shown) of the film substrate. When the display surface of this cholesteric liquid crystal display element was pressed with a finger, the display state of the part shown by the broken line pattern 46 of FIG. 6 changed easily. In addition, when the cholesteric liquid crystal display element was bent in the longitudinal direction and bent, the change in the display state was not smooth compared with the case where the finger was pressed, but also in the portion indicated by the broken line pattern 46 in the display state. Change was seen.

A cholesteric liquid crystal is a liquid crystal in which a liquid crystal molecule has a spiral shape, and includes two kinds of planar states in which light of a specific wavelength is reflected (selective reflection) and transparent focal conic states according to the direction of change of the spiral structure. It is known as a bistable liquid crystal taking a state. In the planar state, the spiral axis is perpendicular to the substrate surface, and the liquid crystal molecules are parallel. In the focalconic state, the helix axis is parallel to the substrate surface and the liquid crystal molecules form micro domains. The cholesteric liquid crystal display element displays using these two states.

The change in the display state due to the pressure on the display surface and the bending of the element found in the experiments 1 and 2 is attributable to the change of the cholesteric liquid crystal from the focalconic state to the planar state. This is because the liquid crystal inside the segment (hereinafter sometimes referred to as a liquid crystal cell) flows, the liquid crystal molecules are attracted to the interface of the substrate, and the liquid crystal molecules become parallel to the substrate and change into a planar state. do. The change position of the display state shown by the broken line pattern in FIG. 5 and FIG. 6 is a part in which a liquid crystal tends to flow by the pressure change inside a liquid crystal cell in structure. Moreover, when the thickness (cell gap) of a liquid crystal cell was 3 micrometers and 5 micrometers, the change of a display state was remarkable for the thinner 3 micrometer cell gap. It is thought that this is because the 3 µm side is more likely to be affected by the interface of the substrate because there are many liquid crystals near the interface of the substrate.

Based on the above considerations, it is possible to prevent the change of the display state due to the pressing on the display surface of the liquid crystal display element, the bending of the liquid crystal display element, or the like by forming the wall structure so that the fluidity of the liquid crystal inside the liquid crystal cell is suppressed. Revealed.

There are two types of loads applied when the surface of the liquid crystal display element is pressed, "equal distribution load" and "concentration load". The equal distribution load is a load generated when the surface area is pressed by a relatively large surface such as a finger, and the load is uniformly distributed around the pressing portion. The concentrated load is a load generated when the surface area is pressed with a small surface area, such as the tip of a ball pen, the finger nail of a finger, or the like, and the load concentrates on the pressing portion and is not distributed very much around.

In the embodiments described below, first, an embodiment that copes with the change in the display state due to an equally distributed load will be described. Next, an embodiment that copes with the change in the display state due to the concentrated load will be described.

Also in any Example, the whole structure (position of each component) is the same as that of the liquid crystal display element proposed by patent document 3 shown in FIGS. The essential difference between them lies in the structure of the liquid crystal cell layer. In the present invention, by studying the structure of the wall structure (in other words, the pattern shape of the display portion and the liquid crystal injection path) or the structure inside the segment (liquid crystal cell) in the wall structure, an equal distribution load and a concentrated load are compared to conventional liquid crystal display elements. To increase the intensity.

7 is a graph showing the load-bearing effect in the liquid crystal display device of the embodiment of the present invention.

This graph shows the display change by the "equal distribution load" applied to the display surface, such as a person pressing a display surface of the liquid crystal display element with a finger, and the horizontal axis represents the conventional liquid crystal display element and the present invention. The liquid crystal display element and the vertical axis | shaft of each Example are set to those "withstand load (kgf / cm <^2> ). Withstand load indicates the maximum pressure (hereinafter, referred to as "pressure pressure") of the maximum finger which the liquid crystal display element can withstand display change when a person presses the display surface of a liquid crystal display element with a finger.

The horizontal line 51 of the broken line of the same graph is 5.3 kgf / cm <^2> as the minimum target value of the withstand load at the time of mounting a liquid crystal display element as a display element of an IC card. This target value is a value derived statistically from the measurement results of the tens of people who participated in the experiment and can be regarded as an average of the man's average pressure.

In the liquid crystal display element of the conventional structure which has the liquid crystal cell of FIG. 3, the withstand load in case the thickness of a cholesteric liquid crystal (henceforth a liquid crystal only) is 5 micrometers was 1.6 kgf / cm <^2> . Moreover, when the thickness of the liquid crystal was 3 micrometers, it reduced to 1.3 kgf / cm <^2> . As described above, in the liquid crystal display element of the conventional structure, it cannot hardly bear the human pressure.

Since one cause of the display change of the liquid crystal display element is the outflow of the cholesteric liquid crystal (liquidity of the liquid crystal) due to the deformation of the liquid crystal cell, the deformation strength of the liquid crystal cell against pressure can be increased by increasing the hardness of the wall structure. It is possible to increase the display change due to pressing. Therefore, the material of the wall surface structure was reviewed, and the wall surface structure after adhesive hardening was made into a harder material. Since the wall structure is a polymer material, a material having a large molecular weight and having a high crosslinking density tends to become hard. This method was applied to the liquid crystal display element of the conventional structure of 3 micrometers in thickness of a liquid crystal, and when the wall structure was made into the rigid wall structure, the load capacity increased to 2.7 kgf / cm <^2> .

Thus, in the liquid crystal display element of a conventional structure, even if the hardness of the wall surface structure which is a high molecular material is raised, the load capacity does not reach a target value. Therefore, in the Example of this invention, the pattern shape of the wall surface structure was changed so that it was possible to suppress the flow of the liquid crystal in a liquid crystal cell. Noted in the examples are "shape of liquid crystal injection path" and "structure of each segment of the segment block".

The embodiment described below applies the present invention to a liquid crystal display element in which the numerical display portion (hereinafter referred to as a segment block) of each digit of the display portion is composed of seven segments.

Example 1

8 is a partial horizontal cross-sectional view of the liquid crystal cell layer in the liquid crystal display element of Example 1 of the present invention.

When the display surface of the liquid crystal display element is pressed with a finger, the load applied to the display surface is called an equal distribution load. In the liquid crystal cell 60 of Example 1 by the magnitude | size of this equally distributed load, paying attention to "the shape of a liquid crystal injection path | route", the liquid crystal injection path 62 which connects between the segment blocks 61 is a key type S-shaped structure. It was set as. Also within the segment block 61, two sets of left and right opposed segments 63 on the upper side and the lower side are connected to each other by a liquid crystal injection path 64 having a key S-shape structure, and the liquid crystal injection path 64 is provided. And each segment 63 of the upper, center and lower portions were connected by a straight liquid crystal injection path 65 which was split longitudinally into the liquid crystal injection path 64. Thus, the liquid crystal injection paths 62 and 64 have a structure using the property that a fluid becomes difficult to flow when there is a corner. Therefore, the liquid crystal injection path 64 may be a structure having a corner in the middle, and is not limited to the key type S-shaped structure.

As shown in Fig. 3, in the conventional liquid crystal display device, although the segment block 4a is not divided into a plurality of segments, in this embodiment, attention is paid to the "structure of the segment", and the segment block 61 is shown in FIG. While dividing into two segments 63, the liquid crystal injection hole (hereinafter, simply referred to as an injection hole) of each segment 63 was set to one. By setting it as such a structure, the number of the segments 63 which do not have a liquid crystal ejection outlet (henceforth simply an ejection outlet) can be made large. Since these segments 63 have no ejection port, the fluidity of the liquid crystal filled therein will be reduced. In the liquid crystal display element of Example 1, the upper part, the center part, and the lower segment 63 are a segment without the ejection outlet which has only an injection opening. In other words, these three segments 63 have a structure connected only to the liquid crystal injection path 64 serving as an injection hole and not connected to the liquid crystal injection path 64 serving as an injection hole of the liquid crystal.

7 shows the effect of increasing the load resistance in the liquid crystal display of Example 1 having the above structure.

As shown by the rhombus with (3) in the same figure, the load capacity of the liquid crystal display element of Example 1 improves to 9.33 kgf / cm <^2> . In addition, although the structural diagram is not shown, the withstand load of the liquid crystal display element having only one segment without a spout in each segment block was 5.6 kgf / cm ² . From this, it was found that the load resistance was changed by the number of segments without the spout.

9 is a diagram illustrating a method of manufacturing the liquid crystal display element of Example 1. FIG.

The manufacturing process of the liquid crystal display element of Example 1 is substantially the same as the liquid crystal display element of patent document 3, and only the formation process (formation process of a wall structure) of a liquid crystal cell layer is different. Therefore, it is briefly described here.

(1) First, the light shielding mask (light shielding film) 72 of a segment pattern is formed on the surface of the film substrate (segment substrate) 71 in which the transparent electrode of the segment pattern was formed.

(2) Next, on the light shielding mask 72, an adhesive wall surface 73 serving as a liquid crystal cell layer in consideration of the liquid crystal injection path is formed by photolithography or the like. The thickness of the wall surface structure becomes almost the thickness of the liquid crystal in the liquid crystal cell layer.

(3) The light absorption layer 75 is formed on the common substrate 74 on which the beta-shaped common electrode 74a is formed. The light absorbing layer 75 is necessary to make the transparent state of the cholesteric liquid crystal black. The light absorbing layer 75 may be formed on either the inside or the outside of the common substrate 74. Alternatively, the common electrode 74a may be formed of a material having light absorptivity (in this case, the step of forming the light absorbing layer becomes unnecessary).

(4) As mentioned above, the segment substrate 76 and the common substrate 77 which were formed separately, are bonded together by heat processing.

(5) Liquid crystal is injected into the liquid crystal injection hole of the liquid crystal cell layer 77, and liquid crystal is injected and charged into all the segments 63 through the liquid crystal injection paths 62 and 64. This liquid crystal injection can be performed by the vacuum injection method, for example.

In the liquid crystal display element 70 shown in FIG. 9, in order to take out the common electrode 74a of the common board | substrate 77 from the segment board | substrate 76, the common board | substrate 77 is common using a conductive adhesive etc. The electrode 74a is energized with the transfer electrode 71a of the segment substrate 76. Moreover, although the wall surface structure 73 itself is equipped with adhesiveness, the substance of the general liquid crystal structure may be provided in the outer peripheral part of a liquid crystal display element.

In the cholesteric liquid crystal display element which does not use a polarizing plate, since a liquid crystal remains in a liquid crystal injection path, a light shielding mask is needed in order to conceal the liquid crystal in this liquid crystal injection path (refer the said process (1)).

By the way, in the case of the liquid crystal display device of the semi-ferroelectric liquid crystal shown in FIG. 4, only a part of the segment (the upper half of the right half, the middle portion, the lower portion, and the upper and lower segments of the right end) does not have an ejection outlet. The entire segment of the outer segment block has an inlet and an outlet. Therefore, even when this liquid crystal display device is used for the liquid crystal display device of the cholesteric liquid crystal, when pressure is applied to the display surface, the fluidity of the liquid crystal inside the segment decreases (in other words, the improvement of the load resistance). You can't expect it.

Thus, although the structure exceeding the target value of withstand load was implement | achieved in the liquid crystal display element of Example 1, the convenience of an IC card improves as the withstand load is large. That is, it is preferable that the display of the IC card does not change even when used in any situation. Therefore, the structure of Example 1 was further developed to devise a liquid crystal display device in which each segment in each segment block has a liquid crystal cell layer having a wall surface structure of one injection hole as described below.

Example 2

Fig. 10 is a partial horizontal cross-sectional view of a liquid crystal cell in the liquid crystal display element of Example 2 of the present invention based on the above invention.

In the liquid crystal cell layer 80 in the liquid crystal display element of Example 2 shown in the same figure, a straight line is parallel with the column of the segment block 81 upward and downward of the column of the segment block 81 connected in the horizontal direction, respectively. The common liquid crystal injection paths 85 and 86 of the shape are provided. Each segment 83 of the upper half of each segment block 81 has a structure in which liquid crystal is injected through the liquid crystal injection path 82 split from the common liquid crystal injection path 85, and each segment 83 of the lower half is formed. ), A liquid crystal is injected through the liquid crystal injection path 82 split from the common liquid crystal injection path 86. The liquid crystal injection path 82 has the shape of a straight line, "approximately scoop type", or "step", and the latter two liquid crystal injection paths 82 have the shape which has a corner part.

Because of this structure, each segment 83 in each segment block 81 has only one injection hole. In addition, since all the segment blocks 81 are connected through the common liquid crystal injection paths 85 and 86, there is no injection port in each segment 83.

Thus, since the liquid crystal display element of Example 2 has the structure where all the segments 83 in the liquid crystal cell 80 do not have an ejection opening, the withstand load improves more than the liquid crystal display element of Example 1. As shown in FIG.

Example 3

11 is a partial horizontal cross-sectional view of the liquid crystal cell layer in the liquid crystal display element of Example 3 of the present invention.

As shown in the same figure, in the liquid crystal cell layer 90 of the liquid crystal display element of Example 3, all the segments 93 of all the segment blocks 91 are independent, and the injection port is also provided in these segments 93 as an injection port. There is no. Therefore, there is no liquid crystal injection path. For this reason, the withstand load of the liquid crystal display element of Example 3 improves more than the liquid crystal display element of Example 2.

In preparation of the structure of the liquid crystal cell layer 90 in the liquid crystal display element of Example 3, a general vacuum injection method cannot be used in the manufacturing process of a liquid crystal panel. However, for example, it can manufacture by the following process.

(1) Only the segment part is a recessed part of a wall surface structure.

(2) A liquid crystal (cholesteric liquid crystal) is dropped in the recess, and the recess is filled with the liquid crystal.

(3) Two opposing substrates (a common substrate and a segment substrate) are bonded together.

In the process of said (2), (3), since a bubble may enter a liquid crystal, it is preferable to perform dripping of liquid crystal and bonding of an opposing board | substrate in vacuum.

The liquid crystal display elements of the said Examples 1-3 are aimed at the improvement of the withstand load of the equal distribution load generate | occur | produced by the pressing force, such as a finger with respect to the display surface of a liquid crystal display element. In the case of the IC card, a situation such as pressing the display portion of the IC card with the tip of a ballpoint pen or the finger nail of a finger is also assumed. In this case, a concentrated load is applied to the display unit, and a change occurs in the liquid crystal display. In order to improve the convenience of the IC card, it is also necessary to suppress the display change caused by this concentrated load.

In the concentrated load, since pressure concentrates in the minute region, pressure is often applied only to individual segments. Since the segment is filled with liquid crystal, the liquid crystal in the segment easily flows due to the concentrated load on the segment. In particular, this tendency is remarkable in a film substrate.

12 shows a state of deformation of a segment that occurs when pressing of a concentrated load is applied.

The segment 100 surrounds the upper and lower surfaces by the counter electrode (common electrode) 104 formed on the common substrate 105 and the segment electrode 107 formed on the segment substrate 101, and the adhesive wall structure 103 It is structured to surround the left and right sides. In addition, a light shielding mask 102 is provided on the upper surface of the adhesive wall surface structure 103. The light shielding mask 102 is sandwiched by the segment substrate 101 and the adhesive wall surface structure 103.

When a pressing force in the direction indicated by the arrow 108 in the drawing is applied to a part of the segment substrate 101 located above the center portion of the segment 100, the circumference around the pressing portion of the segment substrate 101 is pressed. Recessed in the direction, and with this, the liquid crystal in the segment 100 is pressed from the segment electrode 107, and deformation | transformation arises in the segment 100. FIG. When the segment 100 having a width of 0.4 mm was started and the load bearing capacity of the segment 100 was examined, the load capacity of the segment 100 of the conventional structure was 0.6 kgf / cm ² . Thus, the display of the segment 100 of the conventional structure was changed by the pressure of about 0.6 kgf / cm <^2> very weakly with respect to the concentrated load.

Therefore, in order to improve the concentrated load of a segment, it was devised to form an adhesive strut (adhesive strut) also inside the segment of a wall structure. This adhesive strut is intended to hold the opposing substrate similarly to the wall surface structure surrounding the side of the segment. Therefore, it functions to alleviate the pressure applied to the liquid crystal inside the segment.

Example 4

Fig. 13 is a horizontal sectional view of a segment in the liquid crystal display element of Example 4 of the present invention based on the above invention. 14 is a top view when the segment is seen from the display surface side.

As shown in FIG. 13 and FIG. 14, in the segment 110 of the liquid crystal display element of Example 4, columnar adhesive posts (hereinafter simply referred to as posts) 111 are arranged in a column shape at equal intervals. Doing.

15 shows a vertical sectional view of this segment 110. In the same figure, the same code | symbol is attached | subjected to the component same as the component which the segment 100 of the conventional structure of FIG. 12 has.

As shown in FIG. 15, in the segment 110, the strut 111 is arrange | positioned at equal intervals. In this way, by installing the rigid strut 111 inside the segment 100 at equal intervals, the deformation of the segment 110 is suppressed even when a concentrated load is applied, and the display change of the concentrated load of the segment 110 is suppressed. Prevention can be made strong.

In fact, as a result of forming the columnar strut 111 having a diameter of 0.03 mm in the arrangement pattern as shown in FIG. 13 inside the segment 100, as shown in (4) in the graph of FIG. The load improved by 5.5 times to 3.5 kg / cm ² .

Since the material of the support 111 is made of the same material as that of the wall surface structure 113, the formation can be performed in the same process as the wall surface structure 113. For example, if the wall structure 113 is formed by photolithography, a photomask in which the pattern of the strut 111 is applied to the pattern of the wall structure 113 may be produced.

By the way, as shown in FIG. 7 (4), in the liquid crystal display element of Example 4, the load resistance with respect to the equal distribution load is substantially the same as that of the liquid crystal display element of a conventional structure, and it is an immunity effect with respect to the equal distribution load. There was no. Therefore, the structure which improves the tolerance of a concentrated load and also improves the tolerance of a uniformly distributed load was devised further.

Example 5

FIG. 16 is a horizontal cross sectional view showing a shape and an arrangement pattern of struts within a segment in the liquid crystal display device of Example 5 of the present invention. FIG.

In Example 5, the support | pillar 121 was made cross-shaped three-dimensional, and this support | pillar 121 was arrange | positioned in the grid | lattice form at equal intervals inside the segment 120. As shown in FIG. Since the cross section of the support 121 is cross-shaped, the flow path of the liquid crystal is limited to the gap between the crosses, and the fluidity thereof is greatly limited. For this reason, the tolerance of both a concentrated load and an equal distribution load improves.

Example 6

17 is a horizontal cross-sectional view showing the shape and arrangement pattern of struts in a segment in the liquid crystal display element of Example 6 of the present invention.

Inside the segment 130, a support 131 having a honeycomb structure is formed. In this way, in the case where the posts 131 having the honeycomb structure are installed, the segment 130 is most resistant to the concentrated load. In the honeycomb structure, the opening 133 is provided on one side of the regular hexagon.

Example 7

Although not shown, as a liquid crystal display element of Example 7 of the present invention, a liquid crystal display element having a substantially honeycomb structure shown in FIG. 17 and a structure in which all segments shown in FIG. 10 do not have an ejection outlet was produced. As a result, the resistance of the equally distributed load of this liquid crystal display element is 18.7 kgf / cm ² as shown in (5) in the graph of FIG. 7, and the conventional structure shown in (1) in the graph of FIG. It became 10 times or more of the withstand load (= 1.3 kgf / cm <^2> ) of a liquid crystal display element. In addition, the load resistance of the concentrated load was also 12.7 kgf / cm ² , and actually became 20 times or more of the load resistance (= 0.6 kgf / cm ² ) of the liquid crystal display element of the conventional structure.

By the way, in the strut structure of the segment in the liquid crystal display element of Example 6, 7 shown in FIG. 16 and FIG. 17, there are many opening parts into which a liquid crystal enters. However, at least two openings into which liquid crystal enters may be sufficient.

Example 8

18 is a horizontal sectional view of a segment in the liquid crystal display element of Example 8 of the present invention.

The segment 140 shown in the same figure is a modification of the segment 120 shown in FIG. 16, and is different from the left side of one pillar 121 of two adjacent pillars 121 in the segment 120. FIG. The right side of the support 121 has a support 141 connected thereto. As described above, since the segment 140 has a structure in which the struts 121 which are adjacent to each other in the segment 120 are connected to each other, the number of openings is considerably reduced than that of the segment 120. Connection of the support 121 is performed so that the closed area may not be formed in the segment 140. This is to allow the liquid crystal to be injected into the entire region other than the pillar 141 in the segment 140. By the structure as mentioned above, the liquid crystal display element of Example 8 improves the resistance by a uniformly distributed load rather than the liquid crystal display element of Example 6. In addition, since the area ratio of the posts to the total area in the segment cross section is larger than that of the segment 120, the resistance under the concentrated load is also improved than that of the liquid crystal display element of the sixth embodiment.

Example 9

19 is a horizontal sectional view of a segment in a liquid crystal display element of Example 9 of the present invention.

The segment 150 shown in the same figure is a modification of the segment 130 of the substantially honeycomb structure shown in FIG. 17, and the opening part 153 is provided only in two sides of a regular hexagon. For this reason, the flow from the inside of a segment to the outside of the liquid crystal is restrict | limited than the segment 130, and the liquid crystal display element of Example 9 improves the tolerance of a uniformly distributed load than the liquid crystal display element of Example 7. As shown in FIG. Moreover, since the occupation area of the support | pillar in a segment cross section is larger than the segment 130, tolerance of a concentrated load also improves than the liquid crystal display element of Example 7.

In addition, even in a segment having a structure without a liquid crystal injection path as shown in Fig. 11, it is possible to form a support in the segment, and by forming the support in such a segment, it is possible to improve the resistance of the concentrated load and the uniformly distributed load. .

By the way, the smaller the opening, the longer the injection time of the liquid crystal is expected. However, if the temperature of the liquid crystal is lowered and the viscosity of the liquid crystal is lowered at the time of liquid crystal injection, the liquid crystal display element is produced at a time that does not cause a problem processally. It is possible.

As described above, according to the embodiment of the present invention, it is possible to prevent the change of the display state due to the pressing on the display surface, which is a problem peculiar to the cholesteric liquid crystal display device having bistable stability. In addition, a liquid crystal cell resistant to deformation due to warpage can be realized. For this reason, when it is set as the display element of an IC card, the IC card with which the display function excellent in convenience was added can be provided.

Although the said Example applied this invention to the liquid crystal display element of a segment display, this invention is not limited to this, It is applicable to the liquid crystal display element of a dot matrix display.

Moreover, although this invention is an effective structure which prevents the display change which is a problem peculiar to a cholesteric liquid crystal display element excellent in bistable stability, it is also possible to apply the structure of this invention to the durability improvement of another liquid crystal display element.

In addition to the display section of the IC card, the present invention is suitable for a display section of a portable device having a strong request for thinning such as a mobile terminal such as a mobile phone, a personal data assistant (PDA), and a wrist watch. In addition, the present invention can be applied to a display unit of various electronic devices such as a touch panel display, electronic paper, and a vehicle-mounted panel of an automobile.

Claims (10)

Opposing substrate, A wall structure provided between these substrates, A plurality of segment blocks surrounded by side surfaces of the wall structure and each divided into a plurality of segments filled with liquid crystals; One or more liquid crystal injection paths surrounded by sidewalls of the wall structure to connect between segments in different segment blocks or between segments in the same segment block, respectively by being the flow path of the liquid crystal between the segments to be connected. As a liquid crystal display element of the segment display using the cholesteric liquid crystal containing, The wall structure determines a pattern of the plurality of segments and the one or more liquid crystal injection paths, First and second segment blocks of the plurality of segment blocks are connected to each other by the flow path of the liquid crystal formed between the first segment of the first segment block and the second segment of the second segment block, The first and second segments may be connected to separate liquid crystal injection paths, and the flow path formed between the first and second segments may have a common liquid crystal injection path having an outlet at each of the separate liquid crystal injection paths. Including, In each of the plurality of segment blocks, one or more of the segments are connected to the common liquid crystal injection path through only one outlet to one of the one or more liquid crystal injection paths, And at least one of the one or more liquid crystal injection paths has a corner. Opposing substrate, A wall structure provided between these substrates, A plurality of segment blocks surrounded by side surfaces of the wall structure and each divided into a plurality of segments filled with liquid crystals; One or more liquid crystal injection paths surrounded by sidewalls of the wall structure to connect between segments in different segment blocks or between segments in the same segment block, respectively by being the flow path of the liquid crystal between the segments to be connected. As a liquid crystal display element of the segment display using the cholesteric liquid crystal containing, The wall structure determines a pattern of the plurality of segments and the one or more liquid crystal injection paths, First and second segment blocks of the plurality of segment blocks are connected to each other by the flow path of the liquid crystal formed between the first segment of the first segment block and the second segment of the second segment block, The flow path formed between the first and second segments includes one liquid crystal injection path between the first and second segments of the one or more liquid crystal injection paths, In each of the plurality of segment blocks, one or more of the segments are connected to the other one of the plurality of segments through only one outlet to one of the one or more liquid crystal injection paths, And at least one of the one or more liquid crystal injection paths has a corner. The method according to claim 1 or 2, In every segment block, each segment has only one liquid crystal injection path of liquid crystal connected. The method according to claim 1 or 2, A support for holding the opposing substrate is provided inside at least one of the segments. The method of claim 4, wherein The pillar is made of the same material as that of the wall surface structure. The method of claim 4, wherein The pillar has a horizontal cross section of a three-dimensional solid cross-section, characterized in that the liquid crystal display element. The method of claim 6, A pillar having a cross section of the horizontal cross section is connected to an adjacent pillar so that a closed region is not formed in the segment. The method of claim 4, wherein The pillar is a honeycomb structure, and the plurality of sides forming the honeycomb structure have openings. The method according to claim 1 or 2, The at least one liquid crystal injection path having the corner is formed in an S-shaped structure, a ladle shape, or a step shape. delete

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