JP2005250502A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a sharp display picture while making thin a liquid crystal display device in which a liquid crystal display and a coordinate input process are arranged one over the other. <P>SOLUTION: The liquid crystal display device is equipped with: the liquid crystal display 31 which is constituted by charging liquid crystal 8 in a cell 15 having a couple of substrates 5 and 6 arranged opposite to each other and performs display operation in prescribed pixel units; and a coordinate input device 25 which is arranged over the liquid crystal display 31 so as to be in contact therewith and performs switching operation by being pressed to perform the coordinate input process, wherein a barrier 32 is provided between adjacent pixels in the cell 15. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device arranged in a state where a liquid crystal display and a coordinate input process are overlapped.

  In recent years, some electronic notebooks and the like are configured such that a liquid crystal display and coordinate input processing are integrated so that the content displayed on the liquid crystal display can be directly input by pressing with a pen or a finger.

  In this type of liquid crystal display device, a pressing force accompanying the input operation is applied to the liquid crystal display during a pen input or finger input operation.

  Therefore, there is a demand for a liquid crystal display device that can maintain the display on the liquid crystal display in a good state even when the liquid crystal display is pressed with a pen or a finger for the input operation.

  FIG. 10 is a configuration diagram showing a first example of a conventional liquid crystal display device 1.

  The liquid crystal display device 1 shown in the figure has a configuration in which a liquid crystal display 2 and a coordinate input device 3 are overlapped, and the liquid crystal display 2 is displayed below the coordinate input device 3. Therefore, the person who performs the operation is configured to be able to operate the coordinate input device 3 in accordance with the display content displayed on the liquid crystal display 2. In the example shown in the figure, the coordinate input device 3 is configured to input coordinates by pressing the pen 4.

  The liquid crystal display 2 has a structure in which a liquid crystal 8 is filled in a cell formed by a pair of glass substrates 5 and 6 and a frame body 7, and polarizing plates 9 and 10 are provided outside the glass substrates 5 and 6. It is arranged.

  The coordinate input device 3 is composed of a pair of resistance film type tablets 11 and 12, and when a predetermined position is pressed with the pen 4, a resistance corresponding to the pressed position is generated and detected as an electrical signal. Thus, the pressing position is detected. The coordinate input device 3 is configured to be bonded and fixed to the liquid crystal display 2 using a transparent adhesive tape 13.

  As shown in FIG. 10, the liquid crystal display device 1 has a configuration in which the coordinate input device 3 is placed in close contact with the upper portion of the liquid crystal display 2. For this reason, when the coordinate input device 3 is pressed by the pen 4, this pressing force is also applied to the liquid crystal display 2 and the glass substrate 5 is bent. As described above, it is known that when the glass substrate 5 is bent, a phenomenon (display disorder) in which the display of the liquid crystal display 2 becomes unclear occurs in a predetermined range (about 3 cm @ 2) in the vicinity of the pressing point.

  Therefore, conventionally, as in the liquid crystal display device 11 shown in FIG. 11, a gap portion 14 is formed between the liquid crystal display 2 and the coordinate input device 3, and the pressing force generated by pressing the coordinate input device 3. Is prevented by the gap 14 so that it is not transmitted to the liquid crystal display 2. In the figure, reference numeral 16 denotes a holding plate for holding the coordinate input device 3.

  As another method, a liquid crystal display device having a configuration in which a high-strength protective plate is provided on the upper side of the polarizing plate 9 (on the side facing the coordinate input device 3) so that the pressing force is not transmitted to the liquid crystal display 2 is proposed. Has been.

Further, as disclosed in Patent Document 1, a spacer is disposed between a pair of substrates between which liquid crystal is disposed so that even if a pressing force is applied by a pressing operation, the spacer receives a pressing force. A configuration is also provided.
JP-A-62-178926

  However, when the gap portion 14 is formed between the liquid crystal display 2 and the coordinate input device 3, reflection at the air interface existing on the surface of the liquid crystal display 2 and the gap portion 14 is large, and the transmittance is lowered, resulting in a dark liquid crystal display. There was a problem that only the device could be realized.

  On the other hand, an electronic device (for example, an electronic notebook or the like) on which the liquid crystal display device 11 is mounted is desired to be small and thin. However, a gap 14 or a protective plate is provided between the liquid crystal display 2 and the coordinate input device 3. When the liquid crystal display device 11 is disposed, the thickness of the liquid crystal display device 11 becomes large, resulting in a problem that the electronic device cannot be thinned.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid crystal display device capable of realizing a clear display screen while reducing the thickness.

  In order to solve the above problems, the present invention is characterized by the following various measures.

In invention of Claim 1,
A liquid crystal display in which a cell having a pair of substrates disposed opposite to each other is filled with liquid crystal and configured to perform a display operation in a predetermined pixel unit;
In a liquid crystal display device comprising a coordinate input device that is arranged to be superimposed on the liquid crystal display and performs a coordinate input process by performing a switching operation by being pressurized,
A barrier is provided between adjacent pixels in the cell.

In the invention according to claim 2,
The liquid crystal display device according to claim 1.
The barrier is arranged on at least one of a pair of substrates constituting the cell.

Furthermore, in invention of Claim 3,
The liquid crystal display device according to claim 1 or 2,
The barrier is used as a spacer for holding the pair of substrates apart from each other by a predetermined distance.

  Here, the reason why display disturbance occurs in the liquid crystal display 2 when the pressing force is applied to the liquid crystal display 2 and the glass substrate 5 is bent will be considered.

  FIG. 12 shows the liquid crystal display 2 in a state where no pressing force is applied. In the conventional liquid crystal display devices 1 and 11, a liquid crystal having a predetermined alignment (conceptually shows the alignment state in FIG. 12) is used as the liquid crystal 8. Further, the liquid crystal 8 is configured to be movable in the cell 13 formed by the pair of glass substrates 5 and 6 and the frame body 7.

  For this reason, as shown in FIG. 13, when the pressing force F is applied to the liquid crystal display 2 and the glass substrate 5 is bent, the liquid crystal 8 moves (flows) in the direction indicated by the arrow A in the cell 15. As the liquid crystal moves, the liquid crystal molecules of the liquid crystal 8 fluctuate and the regular alignment state is disturbed. It is thought that the light transmittance fluctuates due to this disorder in orientation, and the above-mentioned display disorder occurs.

  In the first and second aspects of the invention, since a barrier is provided between adjacent pixels in the cell, the movement of the liquid crystal in the cell is restricted by the barrier even when a pressing force is applied to the liquid crystal display. Is done. Accordingly, since the liquid crystal movement is suppressed as described above, the liquid crystal alignment is prevented from being disturbed, so that the light transmittance is stable and the display with no display disorder can be realized.

  Further, in the invention described in claim 3, since the separation distance between the pair of substrates constituting the cell can be kept constant by using the barrier as the spacer, this also stabilizes the alignment of the liquid crystal and provides a good screen. Can be realized.

  As described above, according to the present invention, various effects described below can be realized.

  According to the first and second aspects of the present invention, even when a pressing force is applied to the liquid crystal display, the movement of the liquid crystal in the cell is restricted by the barrier, so that the liquid crystal alignment is prevented from being disturbed, and the light transmittance is stabilized. A good screen without disturbance can be realized. Further, since the liquid crystal display and the coordinate input device can be directly overlapped and arranged, the liquid crystal display device can be thinned.

  Further, in the invention described in claim 3, since the separation distance between the pair of substrates constituting the cell can be kept constant by using the barrier as the spacer, this also stabilizes the alignment of the liquid crystal and provides a good screen. Can be realized.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 shows a liquid crystal display device 20 according to a first embodiment of the present invention. The liquid crystal display device 20 according to the first embodiment corresponds to claims 1 to 3 and is characterized in that the alignment of the liquid crystal molecules of the liquid crystal 21 is multi-domained.

  Hereinafter, the configuration of the liquid crystal display device 20 will be described. In FIG. 1, the same components as those shown in FIGS. 10 to 13 will be described with the same reference numerals.

  The liquid crystal display device 20 is configured such that the liquid crystal display 2 and the coordinate input device 3 are overlapped, and the liquid crystal display 2 is displayed below the coordinate input device 3. Therefore, the person who performs the operation is configured to be able to operate the coordinate input device 3 in accordance with the display content displayed on the liquid crystal display 2. Also in this embodiment, the coordinate input device 3 is configured to input coordinates by pressing the pen 4.

  The liquid crystal display 2 is a matrix type display, for example, and has a configuration in which a liquid crystal 21 is filled in a cell 15 formed by a pair of glass substrates 5 and 6 and a frame body 7. Further, polarizing plates 9 and 10 are disposed outside the glass substrates 5 and 6. A plurality of transparent electrodes (not shown) are disposed on the pair of glass substrates 5 and 6 so as to be orthogonal to each other when seen in a plan view.

  The transparent electrodes are arranged so as to extend in the horizontal direction (X direction) and the vertical direction (Y direction), respectively, and an operation voltage is sequentially applied to the transparent electrodes extending in the X direction. When a signal voltage is applied to the transparent electrode extending in the direction and a voltage is applied to each electrode, a liquid crystal display is performed at that position (corresponding to the pixel). In addition, although the example which employ | adopted the matrix type liquid crystal display is given in the present Example, it is also possible to use the liquid crystal display of other structures, such as an active matrix type liquid crystal display.

  The coordinate input device 3 is composed of a pair of resistance film type tablets 11 and 12, and when a predetermined position is pressed with the pen 4, a resistance corresponding to the pressed position is generated and detected as an electrical signal. Thus, the pressing position is detected.

  Each of the resistive film type tablets 11 and 12 has a structure in which a transparent conductive film is disposed on a transparent base film, and the resistive film type tablets 11 and 12 are interposed via spacers 17 so that the transparent conductive films face each other. Are arranged opposite to each other.

  Further, a reference voltage is applied to the transparent conductive film in the opposed state at a constant period. Therefore, by pressing a predetermined position with the pen 4, each transparent electrode comes into contact with the pressed position and becomes conductive, whereby a voltage signal due to a resistance partial pressure between the transparent electrodes (resistance partial pressure corresponding to the pressed position) is generated. It is generated between the two transparent electrodes, and the pressed position can be detected based on this voltage signal (for the basic configuration of the coordinate input device 3, refer to, for example, JP-A-6-175766).

  The coordinate input device 3 configured as described above is adhesively fixed to the liquid crystal display 2 using a transparent adhesive tape 13 (for example, a highly transparent adhesive transfer tape # 9343 manufactured by Sumitomo 3M Limited).

  Here, the liquid crystal 21 filled in the cell 15 will be described.

  In the present embodiment, a liquid crystal in which the orientation of liquid crystal molecules is multidomained is used as the liquid crystal 21. Specifically, the liquid crystal display 2 according to the present embodiment uses a TN type display using a twisted nematic (TN) liquid crystal in which liquid crystal molecules are randomly aligned.

  As described above, the multi-domain liquid crystal 21 is generally called a polymer-dispersed liquid crystal and has a configuration in which liquid crystal molecules are randomly aligned. Since the multi-domain liquid crystal 21 has different alignment directions in the multi-domain, even if movement occurs in the liquid crystal 21, the alignment of the liquid crystal is averaged as a whole. This will be described with reference to FIGS.

  2 and 3 show the cell 15 in an enlarged manner, and a multi-domain liquid crystal 21 is filled between a pair of glass substrates 5 and 6 arranged to face each other. In each figure, a large number of solid lines are shown in the cell 15, but for the convenience of illustration, the solid lines indicate the orientation directions of the liquid crystal in a plurality of domains (regions) in the cell 15. And

  FIG. 2 shows the liquid crystal display 2 in a state where no pressing force is applied. As shown in the figure, the multi-domain liquid crystal 21 has an alignment direction for each of a large number of domains.

  FIG. 3 shows a state in which the pressing force F is applied to the liquid crystal display 2 and the glass substrate 5 is bent. As described above, the bending of the glass substrate 5 causes the liquid crystal 21 to move in the direction indicated by the arrow A in the cell 15.

  However, the multi-domain liquid crystal 21 has various orientation directions for each domain as shown in FIG. 2 even when no pressing force is applied.

  For this reason, even if the liquid crystal 21 moves in the cell 15 and the alignment method in the domain near the pressing point is changed by this movement, the alignment of the liquid crystal 21 is averaged as a whole. Therefore, even if a pressing force is applied, and the liquid crystal 21 moves due to the bending of the glass substrate 5, the variation in transmittance is small, and the occurrence of display disturbance can be suppressed.

  In addition, as described above, the liquid crystal display device 20 according to the present embodiment has a configuration in which the liquid crystal display 2 and the coordinate input device 3 are directly bonded and fixed using the transparent adhesive tape 13. Can be achieved.

  Further, unlike the liquid crystal display device 11 of the conventional configuration shown in FIG. 11, since the gap portion 14 does not exist, it is possible to prevent the transmittance from being reduced due to the gap portion 14, thereby realizing a clear display screen. It becomes possible to do.

  FIG. 4 shows a liquid crystal display device 25 which is a modification of this embodiment. In the first embodiment described above, the resistive film type tablets 11 and 12 are used as the coordinate input device 3. However, the liquid crystal display device 25 according to the present modification example includes the electrostatic capacitance type tablet 27 and the coordinate input device 26. 28 is adopted.

  The electrostatic capacitance type coordinate input device 26 applies a predetermined potential to the electrostatic capacitance type tablets 27 and 28 and presses them with the pen 4, thereby electrostatic capacitance between the electrostatic capacitance type tablets 27 and 28. It is the structure which detects a press position by detecting that a capacity | capacitance changes. The capacitance type tablets 27 and 28 are respectively disposed on the opposing surfaces of the pair of glass substrates 5 and 6 constituting the liquid crystal display 2. The use of multi-domain liquid crystal as the liquid crystal 21 is the same as in the first embodiment.

  In the liquid crystal display device 25 configured as described above, the glass substrates 5 and 6 are necessarily bent by the pressing operation of the pen 4 (because the capacitance needs to be changed), but the liquid crystal 21 is multi-domained. Therefore, it is possible to prevent display disturbance from occurring for the same reason as described above. In addition, since the liquid crystal display device 25 according to this modification is configured such that the coordinate input device 26 is incorporated in the liquid crystal display 2, the liquid crystal display device 25 can be further reduced in thickness.

  5 to 7 show a liquid crystal display device 30 according to a second embodiment of the present invention. In addition, the liquid crystal display device 30 according to the present embodiment is similar to the liquid crystal display device 20 according to the first embodiment shown in FIG. The coordinate input device 3 has the same configuration as that of the liquid crystal display device 20 according to the first embodiment. Therefore, the liquid crystal display which is a feature of the present invention is shown in FIGS. Only 31 is shown enlarged. 5 to FIG. 7, the same components as those shown in FIG. 10 to FIG.

  The liquid crystal display device 30 according to the present embodiment is characterized in that a barrier 32 for restricting the movement of the liquid crystal 8 (not a multi-domain liquid crystal) is provided in the cell 15 constituting the liquid crystal display 31. It is.

  The barrier 32 is formed on one or both of the pair of glass substrates 5 and 6, and has a configuration in which a resin such as polyimide is patterned in a cross shape when seen in a plan view. Polyimide patterning technology has been established, and processing up to several μm is possible. In this embodiment, the height of the barrier 32 is 5 μm.

  The height of the barrier 32 is set to be equal to the distance between the pair of glass substrates 5 and 6 constituting the liquid crystal display 31. Therefore, as shown in FIG. 5, the barrier 32 also functions as a spacer for holding the pair of glass substrates 5 and 6 in a state of being separated by a predetermined distance. As a result, the orientation of the liquid crystal 8 can be stabilized and a good screen can be realized.

  6 and 7 show an example of the arrangement position of the barrier 32. As shown in each figure, a line-shaped portion 34 for defining each pixel 33 is formed in a matrix between adjacent pixels, and the barrier 32 is formed above the intersection of the line-shaped portion 34. Has been.

  The barrier 32 is configured to surround 20% to 80% around each pixel 33 formed in the liquid crystal display 31. The range in which the barrier 32 surrounds the pixel 33 is determined by the viscosity of the liquid crystal 8, the size of the liquid crystal display 31, the size of one pixel, the pressing force applied by the pen 4, and the like.

  In this embodiment, as shown in FIGS. 6 and 7, two barriers 32 are arranged at diagonal positions of each pixel 33, but each pixel 33 is arranged as described above. As long as 20% to 80% of the periphery of the wall can be enclosed, the position of the barrier 32 is not limited to this.

  As described above, in this embodiment, since the barrier 32 is provided between the adjacent pixels 32 in the cell 15, even if a pressing force is applied to the liquid crystal display 31, Movement is restricted by the barrier 32. As described above, since the movement of the liquid crystal 8 is suppressed, the liquid crystal alignment is prevented from being disturbed, so that the light transmittance is stable and the display having no display disorder can be realized.

  In addition, since the liquid crystal display device 30 according to the present embodiment also has a configuration in which the liquid crystal display 31 and the coordinate input device 3 are directly bonded and fixed using the transparent adhesive tape 13, the liquid crystal display device 30 can be thinned. it can.

  In the second embodiment described above, the cross-shaped barrier 32 is integrally formed by processing polyimide. However, instead of this, as shown in FIGS. 8 and 9, a linear bar made of polyimide having a thickness (2.5 μm) which is half of the thickness dimension (5 μm) of the barrier 32 according to the second embodiment. 35 may be prepared, and this may be configured to form the barrier 36 by overlapping and bonding two linear bars 35 in a cross shape at each barrier forming position.

FIG. 1 is a diagram showing an overall configuration of a liquid crystal display device according to a first embodiment of the present invention. FIG. 2 is an enlarged view of the inside of the cell of the liquid crystal display device according to the first embodiment, and is a view showing the alignment of the liquid crystal before the pressing force is applied. FIG. 3 is an enlarged view of the inside of the cell of the liquid crystal display device according to the first embodiment, and is a view showing the alignment of the liquid crystal after the pressing force is applied. FIG. 4 is a diagram showing a liquid crystal display device which is a modification of the first embodiment. FIG. 5 is a diagram showing a liquid crystal display provided in the liquid crystal display device according to the second embodiment of the present invention. FIG. 6 is a diagram illustrating an example of an arrangement position of the barrier. FIG. 7 is a diagram illustrating an example of the arrangement positions of the barriers. FIG. 8 is a diagram for explaining a liquid crystal display device which is a modification of the second embodiment of the present invention. FIG. 9 is a diagram for explaining a liquid crystal display device which is a modification of the second embodiment of the present invention. FIG. 10 is a diagram illustrating an example of a conventional liquid crystal display device. FIG. 11 is a diagram illustrating an example of a conventional liquid crystal display device. FIG. 12 is a diagram illustrating a liquid crystal alignment state of a liquid crystal display in a state where no pressing force is applied in a liquid crystal display device having a conventional configuration. FIG. 13 is a diagram illustrating a liquid crystal alignment state of a liquid crystal display in a state where a pressing force is applied in a liquid crystal display device having a conventional configuration.

Explanation of symbols

2,31 Liquid crystal display 3,26 Coordinate input device 4 Pen 5,6 Glass substrate 8,21 Liquid crystal 9,10 Polarizing plate 11,12 Resistive film type tablet 13 Transparent adhesive tape 15 Cell 20,25,30 Liquid crystal display device 27, 28 Capacitance tablet 32, 36 Barrier 33 pixels

Claims (3)

A liquid crystal display in which a cell having a pair of substrates disposed opposite to each other is filled with liquid crystal and configured to perform a display operation in a predetermined pixel unit;
In a liquid crystal display device comprising a coordinate input device that is arranged so as to be in close contact with the liquid crystal display and performs a coordinate input process by performing a switching operation by being pressurized,
A liquid crystal display device, wherein a barrier is provided between adjacent pixels in the cell. The liquid crystal display device according to claim 1.
The liquid crystal display device, wherein the barrier is disposed on at least one of a pair of substrates constituting the cell. The liquid crystal display device according to claim 1 or 2,
A liquid crystal display device, wherein the barrier is used as a spacer for holding the pair of substrates in a state separated by a predetermined distance.

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