JP2009199095A - Driving method of liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device with coordinate input capable of reducing cost by a simple structure, and reducing a thickness without degrading display quality. <P>SOLUTION: A pressure sensitive switch 23 formed of known pressure sensitive conductive material is arranged between a black mask 22 and a common electrode 21, which are known components of a liquid crystal display panel 20. With this structure, a function of a known resistive film type (analog) touch panel can be included. In addition, because existing components are used, it is easy to reduce cost, and the thickness can be reduced. Furthermore, because a touch panel part is not overlapped on the liquid crystal display panel 20, the display quality is not degraded due to parallax. When the pressure sensitive switch 43 is arranged between signal electrodes 41 and scan electrodes 42 of a known simple matrix type liquid crystal display panel 40, the function of a known resistive film type (digital) touch panel can be included, and similar effect can be achieved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a display device with a coordinate input function using a liquid crystal display device.

Along with the rapid computerization of society, demand for touch panels is rapidly growing as an input device that allows anyone to easily access a personal computer. The touch panel is an input device that is arranged in front of various displays and performs pointing by touching the surface of the touch panel with a finger or a pen.
On the other hand, among various displays, in particular, liquid crystal display panels (hereinafter referred to as “LCDs”) are rapidly becoming popular because of their remarkable cost reduction and high functionality. It is increasing rapidly. Accordingly, the use of touch panels used in combination with LCDs has been dramatically expanded.
Applications of the touch panel include electronic notebooks, financial terminals (CDs and ATMs), ticket machines, various monitors, remote controllers, handy terminals, POS terminals, word processors, PPCs, FAXs, etc. Demand for communication equipment such as car navigation systems is also growing.

As the touch panel, a resistive film method, an optical method, a capacitance method, a magnetic induction method, an elastic wave method, and the like have been put into practical use according to the input position detection method. Among them, many practical examples are found in the touch panel using the resistive film method.
A resistive film type touch panel is configured such that a resistive film serving as electrodes on the upper and lower sides is arranged in a state of being electrically separated via, for example, a well-known spacer member, the upper electrode is a movable electrode, and the lower electrode is a fixed electrode The position is detected by utilizing the fact that the movable electrode and the fixed electrode are short-circuited at the pointed portion when the upper electrode side is pointed (not shown). The position of the resistive film type is detected by providing a potential gradient in a certain direction on at least one resistive film, and measuring the voltage drop when the upper electrode and the lower electrode are short-circuited at the pointed portion. Thus, the position is detected.
In addition, in the resistive film type touch panel, as described above, in order to have a potential gradient, the resistive film needs to have conductivity and preferably has a relatively high resistance value. .

  The resistive film type touch panel may be a system (analog type) that can continuously detect an arbitrary position by giving a potential gradient to both ends of each resistive film, or a resistive film that is arranged vertically. A system (digital type) or the like is used in which a matrix circuit can be configured by arranging a large number of strip electrodes so as to extend in directions orthogonal to each other.

  As described above, since the touch panel performs pointing by touching with a finger or a pen or the like, a picture such as a button is formed on a portion to be pointed on the LCD. Each pattern is designed so that, for example, you can select several options when pointing, or you can enter numbers. Which pattern on the LCD corresponds to which operation? Letters are written so that you can understand. The operator visually recognizes the pattern on the LCD and performs pointing.

When the pointing is performed on the touch panel, the above-described pattern formed at the position where the pointing is to be performed is displayed on the screen of the LCD, for example. That is, the operator sees the picture to be pointed through through the touch panel.
Therefore, due to the difference between the air outside the touch panel and the refractive index inside the touch panel, the actual position of the pattern (the position displayed on the LCD surface) and the position where the operator visually recognizes the pattern (the position viewed through the touch panel) If the parallax between the actual position and the position to be visually recognized is large, the operator cannot point to the correct position. Therefore, when applying a touch panel, it is essential to consider this point.
In addition, the parallax between such an actual position and the position to be visually recognized becomes more noticeable as the thickness of the touch panel is increased.

In addition, since the touch panel is arranged on the front surface of the LCD, the display on the LCD is displayed through the touch panel. Therefore, the thickness of the touch panel increases when the touch panel is transmitted. It is easy to cause a decrease in transmittance and unnecessary reflection. In such a case, the display quality is likely to be impaired.
As a solution for improving the deterioration of display quality, for example, an attempt is made to suppress the deterioration of display quality by taking an optical matching between the LCD and the touch panel. It has not been a means for suppressing the deterioration of display quality.

  In addition, since a conventional display device having a touch panel function has a touch panel portion separately prepared on the front surface of various displays (for example, LCDs), an extra configuration tends to increase and cost reduction is achieved. In addition to being difficult, the thickness of the display device having the touch panel portion is likely to be hot.

  The present invention has been made in view of the above circumstances, is not accompanied by a reduction in display quality as described above, can be reduced in cost because of its simple configuration, and is thin. An object of the present invention is to provide a display device with coordinate input using a resistive touch panel.

  The display device with a coordinate input function according to claim 1 of the present invention is formed by sealing a liquid crystal between two transparent substrates having electrodes on the inner surface, and formed on one transparent substrate. A coordinate input function using a liquid crystal display device in which a transparent common electrode is formed over almost the entire display area of the transparent substrate and a vertical and horizontal grid-like black mask is formed on one transparent substrate. A display device provided between the common electrode and the black mask, wherein the common electrode and the black mask are disposed at a position where the pressing force is applied in response to an external pressing force. Coordinate position detection for detecting a voltage that is displaced according to the position when the pressure-sensitive switching means for conducting, the common electrode, and the black mask are conducted by the pressure-sensitive switching means. Characterized by comprising a stage.

According to the above configuration, the common electrode and the black mask of the liquid crystal display device function as two resistive films of a so-called analog resistive film type touch panel.
That is, the common electrode and the black mask are arranged in parallel in a state of being insulated from each other, and when pressed between them, pressure-sensitive switching means for conducting the common electrode and the black mask at the pressed position is provided. The arrangement basically has the same configuration as the two resistive film portions of the analog resistive film type touch panel, and can function as a resistive film type touch panel.
Accordingly, there is no need to provide a touch panel on the transparent substrate on the surface side of the liquid crystal display device as in the prior art, and a phenomenon such as parallax or deterioration in display quality caused by placing the touch panel on the surface of the liquid crystal display panel occurs. In addition, a coordinate input function can be added to the liquid crystal display device.

In addition, a detection part (that is, two resistive film parts) excluding the circuit part of the touch panel is disposed in the liquid crystal display panel, and a common electrode and a black mask in the liquid crystal display panel have conventionally been used as the resistive film. Since it functions, the liquid crystal display panel itself does not become thick even when the touch panel is built in the liquid crystal display panel. That is, there is an advantage that the coordinate input function can be included in the liquid crystal display device, and the mounting space does not increase even if the coordinate input function is added. In addition, there is an advantage that the mounting weight hardly increases.
Therefore, it is possible to reduce the thickness of the display device with a coordinate input function.

  A black mask used as a resistance film needs to have conductivity and a relatively high resistance value. For example, a metal oxide film having conductivity and a high resistance value is used as a black mask. For example, chromium oxide conventionally used as a black mask can be suitably used as a black mask.

  Moreover, ITO is generally used as the common electrode used as the resistance film, but ITO also needs to have a relatively high resistance value, and has a relatively low resistance value used in a liquid crystal display device of a touch panel. ITO having a slightly higher resistance than ITO is preferred.

  In addition, the common electrode and the black mask need to be insulated at all times except for the pressure-sensitive switching means. For example, in a color liquid crystal display device, the color between the black mask and the common electrode A filter is often formed, and the color filter functions as an insulator. In this case, it is necessary not to provide a color filter in the portion where the pressure sensitive switching means is provided. Further, instead of the color filter, a transparent insulator may be provided between the common electrode and the black mask.

  The pressure-sensitive switching means is, for example, at a pressing position or in the vicinity thereof by pressing a pen, a finger, or the like on the transparent substrate (the black mask may have a black mask at the pressing position because the black mask has a lattice shape). As long as the common electrode and the black mask can be short-circuited, a space filled with fluid may be used in some cases. However, considering the influence on the display and the influence on the structure, it is preferable that the amount of deformation of the transparent substrate, the black mask, the common electrode, etc. be as small as possible. It is preferable to use a solid material that contains a large number of conductive particles in the body and generates conductivity by contact between the conductive particles when pressure is applied.

  The display device with a coordinate input function according to claim 2 of the present invention is the display device with a coordinate input function according to claim 1, wherein the two transparent substrates are opposed to the pressing force acting on the pressure-sensitive switch means. It is characterized by comprising counter-pressing means (columnar gap member 25) for suppressing the thickness of the liquid crystal sealed between them from fluctuating from the pressing force.

According to the above configuration, when a pressing force for inputting coordinates by a pen, a finger, or the like is applied, members such as the transparent substrate, the common electrode, the black mask, and the pressure-sensitive switching means are bent toward the liquid crystal side. Can be prevented by the counter-pressing means.
That is, when a transparent substrate is pressed, liquid crystal that can flow between the two transparent substrates is sealed, so that the transparent substrate is easily bent as described above. Therefore, the above-described deflection can be prevented because the counter-pressing means is pushed back by a reaction force or the like corresponding to the pressing force.
As a result, it is possible to prevent the display from being disturbed in the pressed portion, and the transparent substrate, the common electrode, the black mask, and the pressure-sensitive switching means are bent together, so that the pressure-sensitive switching means is not applied with much pressure when pressed. Can be prevented and sensitivity can be improved.

In addition, if the transparent substrate, common electrode, black mask, pressure-sensitive switching means, etc. are repeatedly bent by the pressing force for coordinate input as described above, the damage to the structure of the liquid crystal display device is greatly reduced. can do.
Note that a spherical gap material is generally placed in the liquid crystal portion of the liquid crystal display device, but the spherical gap material may move when pressed, and the anti-pressing means of the present invention It is hard to fall.
That is, it is preferable that the counter pressing means is disposed between the two transparent substrates so as not to move during pressing.

  The display device with a coordinate input function according to claim 3 of the present invention is the display device with a coordinate input function according to claim 2, wherein the counter pressing means is provided in a liquid crystal portion between the two transparent substrates. It is characterized by being a columnar gap material 25.

According to the above configuration, since the counter-pressing means is a columnar gap material, unlike a general spherical gap material, it does not move, and in the pressing portion by a pressing force for coordinate input, It is possible to prevent the thickness of the liquid crystal from fluctuating.
Therefore, an effect similar to that of the second aspect can be obtained.

  The display device with a coordinate input function according to a fourth aspect of the present invention is the display device with a coordinate input function according to the third aspect, wherein the columnar gap material serving as the counter-pressing means is the black mask and the pressure-sensitive switching means. It is arrange | positioned in the position which overlaps with.

According to the above configuration, since the columnar gap material is formed so as to overlap the black mask, the columnar gap material is hidden by the black mask and does not affect the display, thereby improving display quality. be able to. Therefore, the columnar gap material does not have to be transparent, and the degree of freedom of materials that can be used for the gap material is increased.
In addition, since the columnar gap material is arranged so as to overlap the pressure-sensitive switching means, the above-described deflection can be prevented in the portion where the pressure-sensitive switching means is provided, and the sensitivity of the pressure-sensitive switching means. Can be improved.
As will be described later, the black mask and the pressure-sensitive switching means preferably overlap each other. In this case, if a columnar gap material is overlapped on either side, it will necessarily overlap both.

  The display device with a coordinate input function according to claim 5 of the present invention is the display device with a coordinate input function according to claim 3 or 4, wherein the columnar gap members serving as the pressing means are respectively determined in advance in the vertical and horizontal directions. It is characterized by being arranged at intervals.

According to the above configuration, when a pressing force for inputting coordinates is applied, in a portion where the columnar gap material is present, the pressing force acts from the transparent substrate side where the common electrode is provided, and the reaction force from the gap material. As a result, a large pressure is applied. Therefore, when a pressing force is applied in the vicinity of the columnar gap material, the common electrode and the black mask are short-circuited not at the position where the pressing force is applied but at the position of the gap material in the vicinity thereof. Therefore, if the gap material is arranged to some extent densely, the short circuit between the common electrode and the black mask is limited to the position of the columnar gap material.
Here, if the columnar gap material is arranged at a predetermined interval, the resolution as the touch panel can be determined by the gap material interval.

  The display device with a coordinate input function according to a sixth aspect of the present invention is the display device with a coordinate input function according to any one of the first to fifth aspects, wherein the pressure-sensitive switching means is provided on one transparent substrate. It is provided on the black mask formed so as to be within the black mask forming range.

According to the above configuration, since the pressure-sensitive switching means does not protrude from the black mask and the pressure-sensitive switching means does not affect the display, even if the pressure-sensitive switching means is disposed in the liquid crystal display panel, Deterioration of display quality can be prevented.
In addition, since the pressure-sensitive switching means does not affect the display, it is not particularly necessary to use a transparent pressure-sensitive switching means, and the degree of freedom of members and structures that can be used as the pressure-sensitive switching means is increased. it can.

  In the display device with a coordinate input function according to claim 7 of the present invention, for example, as shown in FIGS. 1 and 2, in the display device with a coordinate input function according to any one of claims 1 to 6, The coordinate position detection means includes a right upper terminal, a lower right terminal, an upper left terminal, and a lower left terminal respectively formed at four corners of one of the common electrode and the black mask, and a pair of upper right terminals A pair of terminals and a lower right terminal, a pair of left upper terminals and a lower left terminal connected to the high voltage side, and the other pair of terminals connected to the low voltage side; A switch that switches between a state in which one of the upper right terminal and the upper left terminal and a pair of the lower right terminal and the lower left terminal are connected to the high voltage side and the other pair of terminals are connected to the low voltage side. And the other resistive film A low voltage side electrode formed so as to substantially surround the periphery and connected to the low voltage side, a voltmeter for measuring a voltage drop due to the resistance film in the low voltage side electrode, and coordinates for obtaining a coordinate position from the value of the voltmeter And a position calculation processing means.

  According to the above configuration, in the display device with a coordinate input function according to the present invention, the first electrode and the second electrode of one of the resistance films are similar to the well-known analog type resistance film type (four-wire type) touch panel. With the potential gradient formed between them, one resistance film and the other resistance film are short-circuited at the coordinate input position, and the voltage at the position is taken out to the other resistance film side and measured, thereby measuring the input position. Can be sought. In addition, by switching the first switch and the second switch, the coordinate of the one resistive film and the other resistive film is coordinated with a potential gradient formed between the third electrode and the fourth electrode of the other resistive film. The input position can be obtained by short-circuiting at the input position and taking out and measuring the voltage at the position to one resistance film side.

  The display device with coordinate input function according to claim 8 of the present invention is the display device with coordinate input function according to any one of claims 1 to 6, as shown in FIG. The detecting means 24 includes an upper right terminal 33 formed at each of the four corners of one of the two common electrodes (common electrode 21) and the black mask (black mask 22) serving as the two resistive films. A lower terminal 34, an upper left terminal 35, and a lower left terminal 36 are provided, and one pair of terminals of the right pair of upper right terminals and lower right terminals and the left pair of upper left terminals and lower left terminals is connected to the high voltage side. And connecting the other pair of terminals to the low voltage side, one pair of the upper right terminal and the upper left terminal, and the lower pair of the lower right terminal and the lower left terminal to the high voltage side. Connected to the other pair A switch 37 for switching between a state in which the child is connected to the low voltage side, a low voltage side electrode 38 formed so as to substantially surround the other resistance film and connected to the low voltage side; A voltmeter 39 for measuring a voltage drop due to the resistance film and a coordinate position calculation processing means 2E for obtaining a coordinate position from the value of the voltmeter are provided.

According to the above configuration, in the display device with a coordinate input function of the present invention, like the well-known analog resistive film type (five-wire type) touch panel, the pair of upper right terminal and lower right terminal of one resistive film In a state where a potential gradient is formed between the pair of upper left terminal and lower left terminal, one resistance film and the other resistance film are short-circuited at the coordinate input position, and the voltage at the position is moved to the other resistance film side. The information of the input position can be obtained by taking out and measuring.
Further, by switching the switches, one resistance film and the other resistance are formed in a state where a potential gradient is formed between the pair of upper right terminal and upper left terminal and the pair of lower right terminal and lower left terminal of one resistance film. Information on the input position can be obtained by short-circuiting the film at the coordinate input position and taking out and measuring the voltage at the position to the other resistance film side.

Also, in this case, a potential gradient is formed in one resistance film, and only a negligible potential gradient is formed in the other low resistance sheet, so that the other resistance film has a high sheet resistance value. There is no need. Therefore, if the other resistive film is a common electrode made of ITO, it is not necessary to use a high resistance value as ITO, and a low sheet resistance suitable for the common electrode can be used. Thereby, even if the common electrode is used as the resistance film, the influence on the display quality, particularly the response speed can be avoided.
Moreover, durability can be improved by making one resistance film exclusive for the resistance film which forms a potential gradient.

  The display device with a coordinate input function according to claim 9 of the present invention is formed by sealing liquid crystal between two transparent substrates having electrodes on the inner surface, and a large number of stripe-shaped signal electrodes 41, A display device with a coordinate input function using a simple matrix type liquid crystal display panel 40 (liquid crystal display device) having 41... And a large number of stripe-shaped scanning electrodes 42, 42. A pressure-sensitive switch 23 (pressure-sensitive switching means) formed at the intersection of these electrodes between the signal electrode and the scanning electrode, and the signal electrode and the operation electrode by the pressure-sensitive switching means. Coordinate position detecting means 44 for detecting a location where a short circuit occurs between the electrodes by sequentially applying a voltage to one of the electrodes is provided.

According to the above configuration, the striped scanning electrode and the signal electrode made of transparent electrodes basically have the same configuration as the two striped resistive films (electrodes) of the digital resistive film type touch panel. After that, only by providing the pressure-sensitive switching means and the coordinate position detecting means, it functions as a touch panel. Therefore, it is possible to achieve substantially the same effect as that of the first aspect.
Since the pressure-sensitive switching means is basically arranged at the display position, it needs to be in a transparent state or extremely small so as not to disturb the display.
Further, the coordinate position detection means may detect one of the multiple scanning electrodes and signal electrodes that is short-circuited and the current flows through.

  According to the display device with a coordinate input function according to claim 1, the common electrode of the liquid crystal display device and the conductive black mask function as two resistive films of a so-called analog resistive film type touch panel. Thus, the function of the touch panel can be included in the liquid crystal display device.

  Further, since it is not necessary to provide a touch panel on the transparent substrate on the surface side of the liquid crystal display device as in the past, the thickness of the liquid crystal display device is not increased, and the touch panel is stacked on the surface of the liquid crystal display panel. Arrangement does not cause a phenomenon such as parallax or deterioration of display quality. Further, the mounting weight is hardly increased, and therefore the display device with a coordinate input function can be thinned.

According to the display device with a coordinate input function according to claim 2, when a pressing force is applied, the transparent substrate, the common electrode, the black mask, the pressure sensitive switch, and the like of the portion are bent toward the liquid crystal side. This can be prevented by pressing means.
As a result, display disturbance in the pressed portion can be prevented, and the transparent substrate, the common electrode, the black mask, the pressure sensitive switch, and the like are integrally bent, so that the pressure sensitive switching means is not applied with much pressure when pressed. Can be prevented and sensitivity can be improved.
Further, when the transparent substrate, the common electrode, the black mask, the pressure sensitive switch, and the like are repeatedly bent due to the pressing force, the damage given to the structure of the liquid crystal display device can be greatly reduced.

  According to the display device with a coordinate input function according to claim 3, since the counter pressing means is a columnar gap material, unlike a general spherical gap material, it does not move and is used for coordinate input. The pressing force can prevent the thickness of the liquid crystal from fluctuating in the pressing portion. Therefore, an effect similar to that of the second aspect can be obtained.

According to the display device with a coordinate input function according to claim 4, since the columnar gap material is formed so as to overlap the black mask, the columnar gap material may be hidden by the black mask and affect display. Therefore, the display quality can be improved.
In addition, since the columnar gap material is arranged so as to overlap the pressure sensitive switch, the above-described deflection can be prevented in the portion where the pressure sensitive switch is provided, and the sensitivity of the pressure sensitive switch can be improved. Can be planned.

  According to the display device with a coordinate input function according to claim 5, when a pressing force is applied, a reaction force is applied from the gap material in a portion where the columnar gap material exists, so that a large pressure is applied. Become. Therefore, when a pressing force is applied in the vicinity of the columnar gap material, the common electrode and the black mask are short-circuited not at the position where the pressing force is applied but at the position of the gap material in the vicinity thereof. Therefore, if the columnar gap members are arranged at a predetermined interval, the resolution of the touch panel can be determined by the gap member interval.

  According to the display device with a coordinate input function according to claim 6, since the pressure sensitive switch does not protrude from the black mask and does not affect the display, the pressure sensitive switch is arranged in the liquid crystal display panel. In addition, the display quality can be prevented from deteriorating.

According to the display device with a coordinate input function according to claim 7, the X-axis is provided between the first electrode and the second electrode of the black mask in the same manner as a well-known analog resistive film type (four-wire type) touch panel. In a state where a potential gradient along the direction is formed, the black mask and the common electrode are short-circuited at the pressing position, and the voltage at the pressing position is taken out and measured to the common electrode side, whereby the input position on the X axis is measured. Can be sought.
In addition, by switching the switches from the first switch to the third switch in conjunction with each other, a black mask is formed in a state where a potential gradient along the Y-axis direction is formed between the third electrode and the fourth electrode of the common electrode. And the common electrode are short-circuited at the pressing position, and the voltage at the pressing position is taken out to the black mask side and measured, whereby the input position on the Y-axis can be obtained.

According to the display device with a coordinate input function according to the eighth aspect, the coordinates can be detected in the same manner as a well-known analog resistive film type (five-line type) touch panel. That is, the common electrode can be a movable electrode and the black mask can function as a fixed electrode.
That is, a potential gradient can be formed between the pair of upper right terminals and lower right terminals and the pair of upper left terminals and lower left terminals formed at the four corners of the black mask. By short-circuiting at the coordinate input position and taking out and measuring the voltage at the position to the common electrode side, information on the input position can be obtained.
Further, by switching the switches, a potential gradient can be formed between the pair of upper right terminals and upper left terminals and the pair of lower right terminals and lower left terminals of the black mask, and the common electrode and the fixed resistance film 52 are coordinated. Information on the input position can be obtained by short-circuiting at the input position and taking out and measuring the voltage at the position to the common electrode side.

Also, in this case, a potential gradient is formed in one resistance film, and only a negligible potential gradient is formed in the other low resistance sheet, so that the other resistance film has a high sheet resistance value. There is no need. Therefore, if the other resistive film is a common electrode made of ITO, it is not necessary to use a high resistance value as ITO, and a low sheet resistance suitable for the common electrode can be used. Thereby, even if the common electrode is used as the resistance film, the influence on the display quality, particularly the response speed can be avoided.
Moreover, durability can be improved by making one resistance film exclusive as a resistance film which forms a potential gradient.

  According to the display device with a coordinate input function according to claim 9, the striped signal electrodes and the scanning electrodes made of transparent electrodes are basically two striped resistive films of a digital resistive film type touch panel ( Since it has the same configuration as that of the electrode), a function for detecting the coordinate position can be included.

It is drawing which shows the basic principle of the display apparatus with a coordinate input function of the 1st example of embodiment of this invention. It is an equivalent circuit diagram of the figure which shows the basic principle of the said example. It is a figure which shows the cross-section of the display apparatus with a coordinate input function of the said example. It is a graph which shows the experimental result of the relationship between the length of the ITO film | membrane which functions as a resistance film, and a voltage drop in the display apparatus with a coordinate input function of the said example. It is a graph which shows the relationship between an external load and the deflection amount of a transparent substrate at the time of providing the column-shaped gap material as a counter-pressing means in the display apparatus with a coordinate input function of the said example. It is a conceptual diagram for demonstrating the basic principle of the display apparatus with a coordinate input function of the 2nd example of embodiment of this invention. It is drawing for demonstrating the basic principle of the display apparatus with a coordinate input function of the 3rd example of embodiment of this invention.

A display device with a coordinate input function according to a first example of an embodiment of the present invention will be described below with reference to the drawings with reference to FIGS.
FIG. 1 is a schematic diagram for explaining the basic principle of the display device with a coordinate input function of the first example of the present invention, and FIG. 2 is an equivalent circuit diagram of FIG. FIG. 3 is a cross-sectional structure diagram of the display device with a coordinate input function of the first example. FIG. 3 shows a cross-sectional structure diagram when pointing is performed using a pen-shaped input member.
FIG. 4 is a graph showing the relationship between the ITO film length and the voltage drop of the ITO film used as the resistance film in the display device with a coordinate input function of the first example. Further, FIG. 5 is a graph showing the relationship between the external load and the deflection amount of the substrate when the columnar gap member 25 is provided in the display device with a coordinate input function of the first example.

  As shown in FIG. 1, the display device with a coordinate input function of the first example includes a common electrode 21 of the liquid crystal display panel 20 and a black mask 22 made of conductive chromium oxide or carbon black. By using it as two resistive films for performing coordinate position detection (analog type), the liquid crystal display panel 20 incorporates the function of coordinate position detection. The black mask 22 has a plurality of openings in a matrix, and the common electrode 21 is provided corresponding to the entire surface of the black mask 22.

First, the configuration of the display device with a coordinate input function of the first example of the present invention will be described with reference to FIG.
The display device with a coordinate input function of the first example is a liquid crystal display composed of two transparent substrates, a transparent substrate (color filter side substrate 12) disposed in the upper part and a transparent substrate (TFT side substrate 13) disposed in the lower part. It consists of a panel 20.
The transparent substrate (color filter side substrate) 12 disposed on the upper side includes a known polarizing plate 11 on the upper surface, and three colors of red (R), green (G), and blue (B) on the lower surface. Are arranged alternately, and a known black mask 22 is provided between the RGB colors of the color filter 17. Further, a well-known common electrode 21 is provided on the entire lower surface of the color filter 17, and a pressure-sensitive switch 23 made of a pressure-sensitive conductive material is provided between the common electrode 21 and the black mask 22. ing. Further, the alignment film 14 formed below the common electrode 21, the liquid crystal 15 sealed in the liquid crystal display panel 20, and a columnar insulating gap member 25 for creating a space for sealing the liquid crystal 15. And. The pressure-sensitive conductive material is a material having a high resistance when no pressure is applied and a low resistance and conductivity when a predetermined pressure is applied in a predetermined direction.
On the surface of the well-known transparent substrate 13 arranged at the lower part facing the liquid crystal 15, a plurality of pixel electrodes 18 made of ITO, TFTs 19 positioned below the gap material 25 and connected to the respective pixel electrodes 18, The alignment film 30 is provided so as to cover them. A polarizing plate 10 is provided on the lower surface of the transparent substrate 13.
Further, a light source (not shown) such as a well-known backlight or reflector serving as a light source is arranged below the liquid crystal display panel 20 in FIG. 3, thereby configuring a liquid crystal display device.

  And in the display device with a coordinate input function of the first example having the above configuration, it has a configuration necessary as a well-known liquid crystal display device and is provided between the common electrode 21 and the black mask 22 and from the outside. Corresponding to the pressing force, a pressure-sensitive switch 23 (pressure-sensitive switching means) for connecting the common electrode 21 and the black mask 22 at or near the position P where the pressing force is applied, the common electrode 21 and the above-mentioned When the black mask 22 is conducted by the pressure sensitive switch 23, the common electrode 21 and the black mask 22 are used as two resistive films, and the conducting position is detected by the resistive film method. Two transparent substrates (color plates) are opposed to the coordinate position detecting means 24 (shown in FIG. 2) to be described later and the pressing force acting on the pressure sensitive switch 23. The thickness of the liquid crystal 15 sealed in the filter substrate 12 and the transparent substrate 13 on the lower surface is provided with a columnar gap member 25 (counter pressing means) for preventing the thickness of the liquid crystal 15 from fluctuating due to the pressing force. Yes.

  Further, as shown in FIGS. 1 and 2, the display device with a coordinate input function of the first example includes terminals 26 and 27 formed on the upper right end and upper left end of the black mask 22, respectively, A terminal 28 and a terminal 29 respectively formed at the upper right end and the lower right end of the common electrode 21, and a first for switching the terminal 26 and the terminal 28 to be connected to the high voltage side as shown in FIG. The switch 2A, the terminal 27 and the terminal 29 are switched and grounded, the second switch 2B which can be operated in conjunction with the first switch 2A, the terminal 27 and the terminal 29 are switched, and a voltmeter 2D which will be described later. And a third switch 2C that can operate in conjunction with the first switch 2A, and the above-described voltage drop due to the black mask 22 or the common electrode 21 is measured. And pressure gauge 2D, it has become one and a coordinate position calculating processing unit 2E for processing the coordinate position from the value of the voltmeter 2D.

The common electrode 21 is a well-known constituent member of a liquid crystal display panel, and is made of a transparent electrode such as an ITO film, for example. In the first example, as shown in FIG. 3, the color filter 17 is integrally disposed on the lower surface.
The ITO film used as the common electrode 21 generally has both a low sheet resistance allowable range due to a certain response speed and a high sheet resistance allowable range due to a steep potential gradient depending on the distance. It is preferable to use an ITO film that satisfies the above conditions (for example, an ITO film having a low resistance of about several Ω / □ to several tens of Ω / □ is used).

Fig. 4 is a graph showing the distance between two points through which current flows on an ITO film with a sheet resistance of 50Ω / □ and the potential difference detected by a voltmeter connected to the ITO film. The coordinate mm (that is, the distance from the electrode on the high voltage side) was plotted, and the detection voltage V was plotted on the vertical axis. In the measurement, the length of the ITO film is 170 mm and the applied voltage is 5V.
The relationship between the detection coordinates and the detection voltage in the graph shown in FIG. 4 is sufficiently linear, and the inclination of the straight line is not so small as to cause inconvenience in detection, and the coordinate input position can be detected with sufficient resolution. It has become. Therefore, for example, an ITO film having a sheet resistance value of 50Ω / □ can be suitably used as the common electrode 21 in the first example.
On the other hand, the ITO film having a sheet resistance value of 50Ω / □ has a resistance value that can provide a sufficient response speed even when used as the common electrode 21 of the liquid crystal display panel 20, and the liquid crystal display panel 20 operates favorably. be able to.

The sheet resistance value of the ITO film used as the common electrode 21 is not limited to the above experimental value of 50Ω / □, the relationship between the detection coordinates and the detection voltage is linear, and the slope of the straight line is Any device that is not so small as to cause inconvenience in detection and that can provide a sufficient response speed can be preferably used.
In addition, when the in-plane variation of the sheet resistance value of the ITO film becomes large, accurate detection becomes difficult. Therefore, it is preferable to use a uniform resistance film in which the in-plane variation of the sheet resistance value of the ITO film is suppressed.

The black mask 22 is disposed in order to increase the contrast of the screen or to enhance the coloring effect and to sharpen the display image, and is a well-known constituent member in the color liquid crystal display panel. As shown in FIG. 3, the black mask 22 is disposed between the 17 pixels of the color filters of red (R), green (G), and blue (B), and prevents display on the liquid crystal display panel 20. In order not to be, it is formed in a vertical and horizontal grid pattern. And as this black mask 22, it is preferable to use the member which has low reflectivity and good light-shielding property, and has electroconductivity, for example, can use chromium oxide suitably.
However, the material used for the black mask 22 of the first example is not limited to chromium oxide, can increase the contrast of the color liquid crystal display panel as a black mask, and can sharpen the display image, and Any conductive material that can be used as a resistance film can be used.

The pressure sensitive switch 23 is made of, for example, a known pressure sensitive conductive material, and is disposed between the black mask 22 and the common electrode 21 as shown in FIG. The pressure sensitive switch 23 is formed on the black mask 22 so as to be within the formation range of the black mask 22. Further, the arrangement of the pressure sensitive switch 23 is formed in a vertical and horizontal grid pattern (not shown) like the black mask 22 so as not to disturb the display of the liquid crystal display panel 20. Further, the pressure-sensitive switch 23 keeps the black mask 22 and the common electrode 21 in an electrically insulated state in a non-pressure state (that is, not touched), and when the pressure is applied, Since the pressure switch 23 becomes conductive, the black mask 22 and the common electrode 21 can be short-circuited.
For example, the pressure-sensitive switch 23 is preferably made of the above-described known pressure-sensitive conductive material in a thin film shape having a cell gap or less. As a result, the pressure-sensitive switch 23 portion does not become thicker than the liquid crystal 15, so that the liquid crystal display panel 20 can be obtained without deteriorating the display quality, and the liquid crystal display panel 20 is thick. Can be prevented.

In addition, as a material used for the pressure-sensitive switch 23, various pressure-sensitive conductive materials that are electrically insulating in a non-pressure state and have a property of developing conductivity when pressure is applied in the vertical direction are used. It can be used suitably. In addition, since the pressure-sensitive switch 23 is arranged in a vertical and horizontal grid pattern so as to overlap the black mask 22, in the case of a transmission type, it is not particularly necessary to use a transparent one, but a reflection type provided with a reflection member. For display, transparent is preferable.
In addition, it is preferable that the common electrode 22 and the black mask 22 can be short-circuited at the pressing position or in the vicinity thereof (the black mask 22 has a vertical and horizontal lattice shape, so the black mask 22 may not exist at the pressing position). Can be used.
For example, as the pressure-sensitive conductive material, a material in which conductive particles are dispersed using an elastic material as a matrix can be suitably used. As the matrix material, for example, rubber materials and other general resin materials can be suitably used, and as the conductive particles, for example, well-known conductive particles such as carbon black, metal, and alloy are used. It can be used suitably. Further, the shape of the conductive particles is not particularly limited, and may be spherical, needle-shaped or plate-shaped. That is, in the above case, the above-mentioned materials of the matrix material and the conductive particles are not particularly limited, and the pressure-sensitive switch 23 is insulative in a non-pressure state and is conductive when pressure is applied. What is necessary is just to be able to express sex.
For example, if known conductive particles are dispersed in a known rubber material, elasticity can be easily imparted to the pressure-sensitive switch 23, so that it can suitably function as a switch.

The pressure-sensitive switch 23 only needs to be able to short-circuit the common electrode 21 and the black mask 22 at or near the pressed position when a pressure is applied. In addition to being formed of a material, in some cases, a space filled with a fluid imparted with conductivity may be used.
However, considering the influence on the display and the influence on the structure, it is preferable that the amount of deformation of the transparent substrate, the common electrode 21, the black mask 22 and the like is as small as possible, and conductivity is generated by the known pressure as described above. It is preferable to use a solid material.

  In general liquid crystal display panels, the layer thickness of a color filter edge portion (not shown) between the black mask 22 and the common electrode 21 is often not guaranteed. That is, the black mask 22 and the common electrode 21 are not necessarily arranged electrically apart from each other. Therefore, by disposing the pressure-sensitive switch 23 between the black mask 22 and the common electrode 21, the insulation state between the black mask 22 and the common electrode 21 in a non-pressure state can be achieved. It can be guaranteed.

As shown in FIGS. 1 and 2, the coordinate position detector 24 uses the common electrode 21 and the black mask 22 as two resistive films, and the pressure-sensitive switch 23 is activated by pressing force. When the common electrode 21 and the black mask 22 are electrically connected, the position where the pressing force is applied can be detected by a known resistance film system.
The position is detected by measuring the value of the voltage drop in the common electrode 21 and the black mask 22 in a voltmeter 2D described later, and in the coordinate position calculation processing means 2E described later connected to the voltmeter 2D. This is performed by calculating the distance by calculation processing using the value of descent.

In the first example, the columnar gap member 25 is disposed between the common electrode 21 and the TFT 19 as a spacer member for forming a space for enclosing the liquid crystal 15 as shown in FIG. As shown in FIG. 3, the columnar gap member 25 of the first example is arranged at a position overlapping the black mask 22 and the pressure sensitive switch 23. Thus, the columnar gap member 25 is disposed at a position that does not hinder the display of the liquid crystal display panel 20.
In the display device with a coordinate input function of the first example, the columnar gap member 25 is configured so that the thickness of the liquid crystal 15 varies with the pressing force against the pressing force acting on the pressure sensitive switch 23. It has become a deterrent. In addition, this makes it possible to prevent the constituent members of the liquid crystal display panel 20 from being integrally bent when pressed.

FIG. 5 is an experimental result showing the amount of deflection of the color filter side substrate 12 (here, the glass substrate) of the display device with a coordinate input function of the first example in which the columnar gap members 25 are arranged. The thickness of the color filter side substrate 12 is 0.7 mm, which is equal to the thickness of a glass substrate generally used for a liquid crystal display panel. The color filter side substrate 12 is supported only at the lower four corners.
The experimental results shown in FIG. 5 show that in the display device with a coordinate input function of the first example, the intervals at which the columnar gap members 25 are arranged are 0.1, 0.5, and 0.7 mm, respectively. 4 is a plot of the amount of deflection of the color filter side substrate 12 when the pressure applied to the liquid crystal display panel 20 (ie, external load) is changed from 1.0E3 (Pa) to 1.0E6 (Pa).

As shown in FIG. 5, for example, when the interval between the columnar gap members 25 is 0.5 mm, even when an external load of 1.0E5 (Pa) is applied, the deflection amount of the color filter side substrate 12 is 0. It is within the range of 01 to 0.1 μm, and the arrangement of the columnar gap member 25 prevents the constituent members of the liquid crystal display panel 20 from being extremely bent even when pressed. I understand.
With the above amount of bending, the display of the liquid crystal display panel 20 is not disturbed, and the color filter side substrate 12 and the TFT side substrate 13 on the lower surface are not cracked. As a liquid crystal display device including a touch panel function, It can be preferably used.

The columnar gap material 25 is arranged by fixing the lower end portion of the columnar gap material 25 to the TFT side substrate 13. For example, in the case of a generally used spherical gap material, it is not fixed in the liquid crystal display panel. Therefore, when a pressure is applied from the upper surface of the liquid crystal display panel, the spherical gap material moves. Therefore, it is not preferable to use the gap material for the display device with a coordinate input function of the first example. Since the columnar gap member 25 is fixedly arranged, the position thereof does not move even when pressed.
The columnar gap member 25 may have its upper end fixed to the color filter 17 or its upper and lower ends fixed to both the TFT side substrate 13 and the color filter 17. Even when a pressure is applied to the upper surface of the display panel 20, it is only necessary that the columnar gap member 25 does not move inside the liquid crystal display panel 20.

Moreover, it does not specifically limit as a material which comprises the columnar gap material 25, For example, a general resin material can be used suitably.
As described above, the columnar gap member 25 is disposed at a position overlapping the black mask 22 and the pressure sensitive switch 23 inside the liquid crystal display panel 20, so that the display of the liquid crystal display panel 20 is performed. It is not necessary to use a transparent material.

As shown in FIGS. 1 and 2, the terminal 26 and the terminal 27 are disposed at the upper right end and the upper left end of the black mask 22, respectively. The terminal 26 and the terminal 27 are made of, for example, a metal film and are electrically connected to the black mask 22.
The terminal 28 and the terminal 29 are arranged at the upper right end and the lower right end of the common electrode 21, respectively. The terminal 28 and the terminal 29 are made of, for example, a metal film like the terminal 26 and the terminal 27, and are electrically connected to the common electrode 21.
And these terminals 28 and 29 apply a predetermined voltage to the common electrode 21 or the black mask 22 that functions as a resistance film when the position is detected in the first example, In order to measure the potential at a certain position on the black mask 22, it can be used as an electrode when a wiring is drawn out.

  As shown in FIG. 2, the first switch 2 </ b> A is a known switch for switching the terminal 26 and the terminal 28 to connect to the high voltage side. The second switch 2B switches between the terminal 27 and the terminal 29 and is grounded, and can be operated in conjunction with the first switch 2A. Further, the third switch 2C switches between the terminal 27 and the terminal 29 and grounds a terminal different from the terminal to which the second switch 2B is connected through the voltmeter 2D described later, and is interlocked with the first switch 2A. Can be operated.

As described above, the first switch 2A, the second switch 2B, the third switch 2C, and the like can be operated in conjunction with each other.
That is, for example, when the first switch 2A is connected to the terminal 28 side, the second switch 2B is switched to ground the terminal 29 in conjunction with the first switch 2A, and the third switch 2C The terminal 27 can be switched to be grounded via the voltmeter 2D. Conversely, when the first switch 2A is connected to the terminal 26 side, the second switch 2B is switched to ground the terminal 27 in conjunction with the first switch 2A, and the third switch 2C The terminal 29 can be switched to be grounded via the voltmeter 2D.

  The voltmeter 2D is a well-known voltmeter for measuring a voltage, and one end is grounded, and the other end is switched and connected to the terminal 27 or the terminal 29 by the third switch 2C. Thereby, the voltage drop for detecting the coordinate position can be measured. Further, the voltmeter 2D is connected to the coordinate position calculation processing means 2E, and the coordinate position calculation processing means 2E can perform calculation processing using the measured value in the voltmeter 2D.

  The coordinate position calculation processing means 2E is connected to the voltmeter 2D and is a calculation processing device programmed to calculate the coordinate position using the voltage value measured by the voltmeter 2D.

  As described above, in the display device with a coordinate input function of the first example, the terminals 27 and 26 are arranged on the upper left and right edges of the black mask 22, respectively, and the right upper and lower edges of the common electrode 21 are arranged. Although the terminal 28 and the terminal 29 are arranged, the arrangement position of each electrode is not limited to these. For example, even if each terminal is formed on the upper right and left edge portions of the black mask 22 and each terminal is formed on the upper left and right edge portions of the common electrode 21, the function of detecting the coordinate position can be included. it can.

Next, a method for detecting the coordinate position in the display device with the coordinate input function of the first example will be specifically described with reference to FIG.
First, the display operation of the liquid crystal display panel 20 shown in FIG. 3 includes a display mode and a coordinate position input mode. In the display mode, a voltage is applied to the liquid crystal 15 for each pixel by the TFT 19 and the pixel electrode 18. By changing the molecular orientation of the liquid crystal 15, light from the backlight is transmitted to or blocked from the upper part of the liquid crystal display panel 20 to display a color image. In the coordinate position input mode, the display period similar to the display mode and the coordinate position input and detection period are sequentially switched. For display characteristics, it is desirable to set the display period in the coordinate position input mode to a plurality of frame periods, and to shorten the subsequent coordinate position input and detection period.
In the coordinate position input and detection period, as shown in FIG. 3, the position where the pressure is applied when the input point is pressed using a coordinate indicator 2F such as a pen is detected. Is detected by detecting the X coordinate and the Y coordinate of the position pressed by the coordinate position calculation processing means 2E.

  A method for detecting the coordinates of the position where the pressure is applied will be described. FIG. 2 shows an equivalent circuit diagram of the above operation when detecting the XY coordinates. In the equivalent circuit of FIG. 2, on the black mask 22, the resistance value from the terminal 26 to the position P where the pressure is applied is Ra1, the resistance value from the terminal 27 to the position P where the pressure is applied is Ra2, and the common electrode 21, the resistance value from the terminal 28 to the position P where the pressure is applied is Rb1, and the resistance value from the terminal 29 to the position P where the pressure is applied is Rb2, and an equivalent circuit is illustrated.

When a pressure is applied to the liquid crystal display panel 20, the pressure is transmitted to the pressure-sensitive switch 23, and the pressure-sensitive switch 23 that is in an insulating state in the no-pressure state becomes conductive. Here, since the columnar gap member 25 is disposed in the liquid crystal display panel 20 at a position overlapping the pressure sensitive switch 23, the pressure can be transmitted to the pressure sensitive switch 23 with high sensitivity. Therefore, the black mask 22 and the common electrode 21 are electrically short-circuited at the position P where the pressure is applied.
FIG. 1 is a schematic diagram of the above operation, and FIG. 2 is an equivalent circuit diagram in this case. When the pressure is applied, the black mask 22 and the common electrode 21 are electrically short-circuited via the pressure-sensitive switch 23 (illustrated by a dotted line in FIG. 1, illustrated by a black arrow in FIG. 2).

As shown in FIG. 2, the first switch 2A is connected to the terminal 28 side, and in conjunction with this, the second switch 2B is connected to ground the terminal 29, and the third switch 2C is connected to the terminal 27 side. Connect to.
When the switches are connected as described above, a potential gradient is formed between the terminal 28 and the terminal 27 on the common electrode 21 so that the terminal 28 is pulled up to the high voltage side, and a voltage corresponding to the position P is generated. It is detected by the voltmeter 2D and output to the coordinate position calculation processing means 2E.

  Then, by forming the circuit as described above, the voltmeter 2D shows the voltage dropped by the resistance values Ra2 and Rb1, and therefore the sum of the resistance values Ra2 and Rb1. Can be obtained. Then, using the resistance value Rb1, the coordinate position is calculated in the arithmetic processing unit 2EL connected to the voltmeter 2D.

Next, a method of detecting the resistance values Ra1 and Rb2 at the position P where the pressure is applied is performed. Here, the first switch 2A is connected to the terminal 26 side, and in conjunction with this, the second switch 2B is connected so as to ground the terminal 27, and the third switch 2C is connected to the terminal 29 side.
Thereby, a potential gradient in which the terminal 26 is pulled up to the high voltage side can be formed between the terminal 26 and the terminal 29 on the black mask 22.
Therefore, as in the case of obtaining the sum of the resistance values Ra2 and Rb1, the voltmeter 2D indicates the voltage that has dropped due to the resistance values Ra1 and Rb2, and the resistance values Ra1 and Rb2 The sum value can be obtained. Then, using the sum of the resistance values Ra2 and Rb1 and the sum of the resistance values Ra1 and Rb2, the XY coordinates of the position P can be calculated in the arithmetic processing unit.

  For example, when the electrodes are formed on the upper right and left edges of the black mask 22 and the electrodes are formed on the upper left and right edges of the common electrode 21, the position P is detected by the same method as described above. Can do.

  In addition, by repeating the detection of the X coordinate and the Y coordinate of the position where the above pressing is performed at a high speed, not only the single point coordinate but also the continuous coordinate detection can be performed. If this is used, not only the position detection but also the figure or character can be detected as a set of points. For example, on the display device of the first example, the figure can be detected using an input member such as a finger or a pen. It is also possible to provide a function of “handwriting input” for detecting the figure or the character by handwriting the character or the character.

In addition, when a pressure is applied, a reaction force from the columnar gap material 25 acts on a portion where the columnar gap material 25 is present, so that a large pressure is applied. Therefore, when pressing is applied in the vicinity of the columnar gap material 25, a short circuit occurs at the position of the columnar gap material 25 in the vicinity thereof, not at the position where the pressure is applied. The position of the material 25 is limited.
Therefore, the sensitivity and resolution of the function as a touch panel can be adjusted by the interval and the number of the columnar gap members 25.
Therefore, the sensitivity and resolution of the touch panel may be adjusted by adjusting the interval and the number of the columnar gap members 25.

According to the display device with a coordinate input function of the first example of the embodiment of the present invention described above, the common electrode 21 and the conductive black mask 22 which are constituent members of the liquid crystal display panel 20 are analog type. It functions as two resistive films of the resistive film type touch panel, and can include a resistive film type coordinate detection function.
That is, according to the above configuration, in the display device with a coordinate input function according to the present invention, one of the two terminals of the black mask 22 and the common electrode, as in the known analog resistive film type (four-wire type) touch panel. The input position P can be obtained by measuring the voltage by short-circuiting the black mask 22 and the common electrode 21 at the pressed position in a state where a potential gradient is formed between one of the two terminals 21. .

  In addition, it is not necessary to provide a touch panel on the transparent substrate on the surface side of the liquid crystal display panel 20 (that is, the color filter side substrate 12) as in the past. Therefore, it is possible to add a coordinate input function to the liquid crystal display panel 20 without causing parallax or deterioration in display quality due to the touch panel being placed on the surface of the liquid crystal display panel 20.

  Further, since the common electrode 21 and the black mask 22 which are constituent members of the liquid crystal display panel 20 are used to incorporate the coordinate detection function, the liquid crystal display panel 20 itself does not become thick. That is, even if a coordinate input function is added, the mounting space does not increase, so that the thickness can be reduced. Furthermore, the mounting weight hardly increases.

In addition, since the columnar gap material 25 is fixedly disposed on the TFT 19, when a pressing force is applied, the transparent substrate (the color filter side substrate 12 or the transparent substrate 13 on the lower surface) of that portion, the common electrode 21, the black mask 22, the pressure sensitive switch 23, and the like can be prevented from being bent toward the liquid crystal 15 side. That is, since the columnar gap member 25 is pushed back by the reaction force or the like corresponding to the pressing force from the liquid crystal 15 side of the common electrode 21, the above-described bending can be suppressed.
Accordingly, it is possible to prevent the display from being disturbed at the pressed portion, and to allow the pressure sensitive switch 23 to be suitably pressurized when pressed by the component members of the liquid crystal display panel 20 being bent integrally. It is possible to improve the sensitivity.
Further, since the columnar gap member 25 is disposed, it is possible to greatly reduce damage caused when the liquid crystal display panel 20 is repeatedly bent when pressed.

  In addition, when a pressure is applied, at the position of the columnar gap material 25, the pressure is applied and at the same time, a reaction force from the columnar gap material 25 is received. Therefore, the position where the short circuit occurs is limited to the position of the columnar gap member 25. Therefore, the resolution as a touch panel can be controlled by the interval between the columnar gap members 25.

  Further, according to the display device with the coordinate input function of the first example, the columnar gap material 25 is formed so as to overlap the black mask 22 and does not affect the display, so that the display quality is improved. Can be planned. Therefore, the columnar gap material 25 is not necessarily transparent, and the degree of freedom of materials that can be used for the gap material can be increased.

Further, according to the display device with a coordinate input function of the first example, the pressure sensitive switch 23 does not protrude from the black mask 22 and the pressure sensitive switch 23 does not affect the display. Even if it is arranged in the liquid crystal display panel, it is possible to prevent the display quality from deteriorating.
In addition, since the pressure sensitive switch 23 does not affect the display, it is not particularly necessary to use a transparent material as the pressure sensitive switch 23, and the degree of freedom of members and structures that can be used as the pressure sensitive switch 23 is high. can do.

Next, a display device with a coordinate input function according to a second example of the embodiment of the present invention will be described with reference to FIG. FIG. 6 is a conceptual diagram for explaining the basic principle of the display device with a coordinate input function of the second example of the present invention.
Note that the display device with a coordinate input function of the second example is a modification of the first example, and the same components as those of the first example are denoted by the same reference numerals and description thereof is omitted.
And the display device with a coordinate input function of the second example is a known resistive film type using the common electrode 21 and the black mask 22 which are well-known constituent members of the liquid crystal display panel 20 as in the first example. The function of coordinate position detection (analog type) is included.

  In the second example, a terminal is connected to the four corners of the fixed resistance film 52 having a uniform sheet resistance in the plane and having a constant light transmittance as a whole, thereby forming a potential gradient according to the position P. As a resistance film that is arranged on the upper side and has a constant light transmittance as a resistance film that connects the low resistance film 51 to the low voltage side, the position detection function of the resistance film system is included. It is different from the first example.

The display device with a coordinate input function of the second example has the same basic configuration as that of the display device of the first example except for the parts described later, and a liquid crystal display having the cross-sectional structure shown in FIG. A panel 20 is provided.
Then, unlike the first example, the display device with a coordinate input function of the second example is formed at the four right corners of the fixed resistance film 52 as shown in the conceptual diagram of the second example of FIG. 33, lower right terminal 34, upper left terminal 35, lower left terminal 36, low resistance film 51, voltmeter 39 for measuring the potential at the input point of pressing, and coordinates from the value of the voltmeter 39 Coordinate position calculation processing means 2E for calculating the position, and by switching the voltage applied to each terminal formed at the four corners of the fixed resistance film 52, on the fixed resistance film 52 in the X-axis direction or the Y-axis And a switch 37 capable of forming a potential gradient along the direction.

In FIG. 6, the fixed resistance film 52 is disposed below and the low resistance film 51 is disposed above. However, the low resistance film 51 may be disposed below and the fixed resistance film 52 may be disposed above. In any case, in the low resistance film and the fixed resistance film, the upper one is used as a black mask and the lower one is used as a common electrode.
In the display device with a coordinate input function of the second example, the low resistance film 51 has a resistance that can be ignored compared to the resistance of the fixed resistance film 52 as long as the distance between any two points in the plane is about. In other words, the sheet resistance is set sufficiently lower than that of the fixed resistance film 52. That is, the voltage displacement according to the position P substantially depends only on the fixed resistance film 52. If this low resistance film 51 is used as a common electrode, ITO having a sheet resistance value similar to that of a normal liquid crystal display device is used as an ITO film used for the common electrode, and a black mask serving as the fixed resistance film 52 is used instead of the common electrode. A fairly high sheet resistance can be set. In addition, as shown in FIG. 6, a low voltage side may be made into a lower side and a high voltage side may be made into an upper side among a low resistance film and a fixed resistance film.

The upper right terminal 33, the lower right terminal 34, the upper left terminal 35, and the lower left terminal 36 are electrically connected to the four corners of the fixed resistance film 52 as shown in FIG. ITO or other well-known electrodes made of a metal film or the like may be used.
In the display device with a coordinate input function of the second example, these electrodes are switched in the X-axis direction or the Y-axis direction by switching the wiring to the black mask 22 used as a fixed electrode by using a switch 37 described later. A potential gradient along the line can be formed.

The switch 37 is a well-known switch member that can switch the voltage applied to the terminals formed at the four corners of the fixed resistance film 52 in conjunction with each other in order to form a potential gradient in the fixed resistance film 52.
For example, when the switch 37 is connected as shown in FIG. 6, the right pair of upper right terminals 33 and lower right terminals 34 are connected to the low voltage side, and the left pair of upper left terminals 35 and By connecting the lower left terminal 36 to the high voltage side, a potential gradient can be formed in the fixed resistance film 52. Further, the potential gradient can be formed by connecting the upper pair of upper right terminals 33 and upper left terminals 35 to the low voltage side and connecting the lower pair of lower right terminals 34 and lower left terminals 36 to the high voltage side. It is possible.

Next, with reference to FIG. 6 which is a conceptual diagram of the position detection method of the second example, a method of detecting the coordinate position in the display device with a coordinate input function of the second example will be specifically described.
As shown in FIG. 6, a method of detecting the position P where the pressure is applied when the coordinate point 2F is applied to the input point will be described.

  In FIG. 6, on the black mask 22, the resistance value from the pressed position to the upper right terminal 33 is RRU, the resistance value to the lower right terminal 34 is RRL, and the resistance value to the upper left terminal 35 is RLU. The resistance value up to the lower left terminal 36 is shown as RLL.

When a pressure is applied to the liquid crystal display panel 20, the pressure is transmitted to the pressure-sensitive switch 23 as in the first example, and the pressure-sensitive switch 23 that is in an insulating state in the no-pressure state becomes conductive.
Therefore, the low resistance film 51 and the fixed resistance film 52 are electrically short-circuited at the position where the pressure is applied.
FIG. 6 is a schematic diagram of the above-described operation. When the pressure is applied, the low resistance film 51 and the fixed resistance film 52 are moved via the pressure sensitive switch 23 (not shown) at the position P where the pressure is applied. Electrically short-circuited (illustrated by a dotted line in FIG. 6).

  The switch 37 allows the left pair of upper left terminals 35 and lower left terminals 36 to be appropriately connected to the high voltage side, and the right pair of right upper terminals 33 and lower right terminals 34 to be appropriately connected to the low voltage side. It can be.

Since the wiring as described above is formed, the voltmeter 39 shows the voltage corresponding to the voltage drop by the resistance value RLU (or RLL), so that the resistance value RLU (or RLL) can be determined. The resistance value RLU (or RLL) is used to calculate the coordinate position in the coordinate position calculation processing means 2E that is connected to the voltmeter 39 and calculates the coordinate position.
In this case, since the surface resistance of the fixed resistance film 52 serving as a fixed electrode is substantially constant, the resistance value RLU (or RLL) is used to connect the upper left terminal 35 (or the lower left terminal 36) on the fixed resistance film 52. The distance from the position where the pressure is applied can be obtained.

  Next, the switch 37 is switched so that the pair of lower right terminals 34 and the lower left terminals 36 are appropriately connected to the high voltage side, and the pair of upper right terminals 33 and the upper left terminals 35 are appropriately connected to the low voltage side.

When the circuit as described above is formed, the voltmeter 39 shows the voltage corresponding to the voltage drop by the resistance value RRL (or RLL), so that the resistance value RRL (or RLL) can be determined. Then, using the resistance value RRL (or RLL), the coordinate position calculation processing means 2E calculates the coordinate position. In this case, since the fixed resistance film 52 serving as the fixed electrode has a substantially constant surface resistance and a sufficiently low resistance, the lower right terminal 34 (or on the fixed resistance film 52 using the resistance value RRL (or RLL)). The distance between the lower left terminal 36) and the pressed position can be determined.
Thus, two of the terminals 33, 34, 35, and 36 are connected to the positive electrode side, the other is connected to the negative electrode side, and the switch 37 is switched only in accordance with these combinations, whereby the coordinate position calculation processing means 2E Each resistance value RRU, RRL, RLU, RLL is discriminated. Since the sheet resistance in the plane of the fixed resistance film 52 is uniform, the ratios of the resistance values RRU, RRL, RLU, and RLL are the ratios of the distances from the terminals 33, 34, 35, and 36 to the position P, respectively. XY coordinates can be obtained.

  Similar to the display device with the coordinate input function of the first example, the detection of the X coordinate and the Y coordinate of the position where the above pressing is applied is repeated at a high speed, so that not only the single point coordinate but also the continuous coordinate is detected. It will be possible to detect. By utilizing this, it is possible to provide a function of “handwriting input” for detecting a figure or the character by handwriting the figure or the character using an input member such as a finger or a pen.

  According to the display device with a coordinate input function of the second example of the embodiment of the present invention as described above, the low resistance film 51 and the fixed resistance film 52 having conductivity are constituent members of the liquid crystal display panel 20. The basic configuration of functioning as two resistive films of an analog resistive film type touch panel is the same as the display device with a coordinate input function of the first example, and has the same effect as the first example. be able to.

In addition, according to the display device with a coordinate input function of the second example, the coordinates can be detected in the same manner as a well-known analog resistive film type (five-line type) touch panel. That is, in the liquid crystal display panel 20, the low resistance film 51 can be connected to the low voltage side, and a potential gradient can be formed in the fixed resistance film 52.
That is, a potential gradient can be formed between the pair of upper right terminal and lower right terminal and the pair of upper left terminal and lower left terminal of the fixed resistance film 52, and the low resistance film 51 and the fixed resistance film 52 are coordinated. Information on the input position P can be obtained by short-circuiting at the input position and taking out and measuring the voltage at the position to the low resistance film 51 side.
Further, by switching the switches, a potential gradient can be formed between the pair of upper right terminals and upper left terminals and the pair of lower right terminals and lower left terminals of the fixed resistance film 52. The low resistance film 51 and the fixed resistance film 52 is short-circuited at the coordinate input position P, and the voltage at the position P is extracted to the low resistance film 51 side and measured, whereby information on the input position P can be obtained.

  In this case, it is only necessary to form a potential gradient in the X-axis direction or the Y-axis direction only on the fixed resistance film 52, and it is not necessary to form a potential gradient on the low-resistance film 51. Therefore, the low resistance film 51 does not need to have a high resistance value. For example, a low resistance ITO film can be used to obtain a sufficient response speed. Thereby, it is possible to avoid the influence on the display quality, particularly the influence on the response speed.

  For example, the durability of the liquid crystal display panel 20 can be improved by using the fixed resistance film 52 exclusively for a resistance film that forms a potential gradient.

In the display device with a coordinate input function of the second example described above, the low resistance film 51 may be a resistance film that forms a potential gradient, and the fixed resistance film 52 may be connected to the low voltage side.
In this case, since a potential gradient is formed on the low resistance film 51, the resistance value of the ITO film to be used should be one having a high resistance value as in the first example. Is preferred.

Next, a display device with a coordinate input function according to a third example of the embodiment of the present invention will be described with reference to FIG. FIG. 7 is a schematic diagram for explaining the basic principle of the display device with a coordinate input function of the third example of the present invention.
And the display apparatus with a coordinate input function of the third example includes the function of detecting the coordinate position of the resistive film type using the constituent members of the constituent members of the liquid crystal display panel as in the first and second examples. Is.

  In the first and second examples, the common electrode and the black mask, which are well-known constituent members of the liquid crystal display panel, are used as two resistive films for detecting the coordinate position of the well-known resistive film system. By using it, the liquid crystal display panel is supposed to include a coordinate detection function. However, in the display device with a coordinate input function of the third example, a well-known simple matrix type liquid crystal display panel is used with a known component. A difference is that a coordinate detection function is included between a certain signal electrode and a scanning electrode.

The display device with a coordinate input function of the third example includes a well-known simple matrix type liquid crystal display panel (liquid crystal display device), a large number of striped signal electrodes 41, 41, and the signal electrodes 41, 41,. Are formed at intersections of the striped scanning electrodes 42, 42... And the signal electrodes 41, 41... And the scanning electrodes 42, 42. The pressure-sensitive switch 43 (pressure-sensitive switching means) and the location where a short circuit occurs between the signal electrodes 41, 41... And the scan electrodes 42, 42. Are provided with coordinate position detecting means 44 for detecting by sequentially applying voltages to 42, 42.
Further, the display device with a coordinate input function of the third example is a known transparent substrate (not shown) disposed above and below the liquid crystal display panel as a constituent member of the liquid crystal display panel, and a known device formed on the transparent substrate. A polarizing plate (not shown), a known alignment film (not shown) for initial alignment of liquid crystal, a known liquid crystal (not shown), and a color filter (not shown) for color display. ing.

The signal electrodes 41, 41... Function as well-known upper pixel electrodes in a simple matrix type liquid crystal display panel, and are composed of a large number of striped electrodes as shown in FIG.
The scanning electrodes 42, 42... Function as well-known lower pixel electrodes of a simple matrix system, and are composed of a large number of stripe-like electrodes, like the signal electrode 41.
The signal electrodes 41, 41... And the scanning electrodes 42, 42,. In addition, each of the signal electrodes 41, 41... Is provided with independent switches 45, 45..., And when the switches 45, 45. The electrode is grounded via a voltmeter 47. In addition, individual switches 46, 46... Are also arranged on the individual scanning electrodes 42, 42... When the switches 46, 46. It has become a thing.

  The signal electrodes 41, 41,... And the scanning electrodes 42, 42,... Are basically disposed at the display position of the liquid crystal display panel, and are therefore transparent and conductive.

The pressure sensitive switch 43 is provided in each pixel formed at the intersection of the signal electrodes 41, 41... And the scanning electrodes 42, 42. And, for example, it is formed at both front and rear ends of each pixel so as not to disturb the display of the liquid crystal display panel (shown in FIG. 7).
The pressure-sensitive switch 43 is made of a known pressure-sensitive conductive material similar to the first and second examples.
The pressure sensitive switch 43 keeps the signal electrodes 41, 41... And the scanning electrodes 42, 42... In an insulated state in a non-pressure state, and when the pressure is applied to the upper surface of the liquid crystal display panel, The pressure is transmitted to the pressure sensitive switch 43 and becomes conductive, whereby the signal electrodes 41, 41... And the scanning electrodes 42, 42.

  The pressure sensitive switch 43 is basically arranged at a display position that is an intersection position of the signal electrodes 41, 41... And the scanning electrodes 42, 42. It is preferable to arrange them at the front and rear positions.

In addition, about the gap material arrange | positioned inside a liquid crystal display panel, when a press is applied from the outside, two transparent substrates (not shown) arrange | positioned at the upper and lower sides of a liquid crystal display panel will bend, and a display will be carried out. It is not always necessary to use it as long as the quality is not lowered.
And as above-mentioned, when the said transparent substrate bends, when a press is applied, when a display quality falls, for example, the columnar gap material 25 similar to a 1st example and a 2nd example is used. It is good also as what suppresses the bending of the above-mentioned transparent substrate by arrange | positioning. At this time, in order to prevent the deflection, it is necessary that the pressure sensitive switch 43 does not restrict the signal electrode 41, 41... And the scanning electrode 42, 42. is there.
In this case, like the pressure sensitive switch 43, it is necessary to dispose the liquid crystal display panel so as not to disturb the display. For example, as shown in FIG. You can do it.

Next, a method for detecting the coordinate position in the display device with a coordinate input function of the third example will be specifically described with reference to FIG.
First, the operation of a well-known simple matrix type liquid crystal display panel is such that when a certain signal electrode 41 is in a connected state, the individual scanning electrodes 42, 42. A voltage is applied to the corresponding intersections of the electrodes 42, 42... To control the molecular orientation of the liquid crystal 15.

When a pressure is applied to the liquid crystal display panel, the pressure is transmitted to the pressure-sensitive switch 23, and the pressure-sensitive switch 43 that has been in an insulating state in the no-pressure state becomes conductive. Therefore, in the pixel corresponding to the position where the pressure is applied (the pixel corresponding to the pressure sensitive switch 43 arranged in the vicinity of the position where the pressure is applied), the signal electrodes 41, 41. 42, 42... Are electrically short-circuited.
In the simple matrix type liquid crystal display panel, as described above, the switch 45 corresponding to a certain signal electrode 41 is connected and grounded via the voltmeter 47, and the switch 46 corresponding to the scanning electrodes 42, 42. Are sequentially connected, and the scan electrodes 42, 42... Are sequentially connected to the high voltage side.
At this time, since the pressure-sensitive switch 43 is conductive at the pixel corresponding to the input position of the press, the position of the pixel corresponding to the input position of the press is known by the instruction of the voltmeter 47.
From the above, it is possible to detect the position where the pressure is applied.

  According to the display device with a coordinate input function of the third example of the embodiment of the present invention described above, the striped signal electrodes 41, 41... And the scanning electrodes 42, 42. Since it has the same configuration as the two striped resistive films (electrodes) of the resistive film type touch panel, the function of detecting the coordinate position can be included.

21, 31 Common electrodes 22, 32 Black masks 23, 43 Pressure sensitive switches 24, 44 Coordinate position detecting means 25 Columnar gap material 26 First terminal 27 Second terminal 28 Third terminal 29 Fourth terminal 2A First switch 2B First Two switches 2C Third switch 2D Voltmeter 2E Coordinate position calculation processing means 33 Upper right terminal 34 Lower right terminal 35 Upper left terminal 36 Left lower terminal 37 Switch 41 Signal electrode 42 Scan electrode 43 Pressure sensitive switch 44 Coordinate position detection means

Claims (10)

A transparent common in which liquid crystal is sealed between two transparent substrates having electrodes on the inner surface, and the electrode formed on one transparent substrate is formed over almost the entire display area of the transparent substrate. A display device with a coordinate input function using a liquid crystal display device in which a vertical and horizontal grid-like black mask is formed on one transparent substrate while being an electrode,
Pressure-sensitive switching means that is provided between the common electrode and the black mask and electrically connects the common electrode and the black mask at a position where the pressing force is applied in response to a pressing force from the outside. ,
A display device with a coordinate input function, comprising: coordinate position detection means for detecting a voltage that is displaced according to the position when the common electrode and the black mask are conducted by the pressure-sensitive switching means. . The display device with a coordinate input function according to claim 1,
Coordinates comprising counter-pressing means for suppressing the fluctuation of the thickness of the liquid crystal sealed between two transparent substrates against the pressing force acting on the pressure-sensitive switch means due to the pressing force. Display device with input function. The display device with a coordinate input function according to claim 2,
The display device with a coordinate input function, wherein the counter pressing means is a columnar gap member provided in a liquid crystal portion between the two transparent substrates. In the display device with a coordinate input function according to claim 3,
A display device with a coordinate input function, wherein a columnar gap member serving as the counter-pressing means is disposed at a position overlapping the black mask and the pressure-sensitive switching means.   5. A display device with a coordinate input function according to claim 3, wherein the columnar gap members serving as the counter-pressing means are arranged vertically and horizontally at predetermined intervals, respectively. . In the display device with a coordinate input function according to any one of claims 1 to 5,
The display device with a coordinate input function, wherein the pressure-sensitive switching means is provided on the black mask formed on one transparent substrate so as to be within the black mask forming range. In the display device with a coordinate input function according to any one of claims 1 to 6,
The coordinate position detecting means is
A first terminal and a second terminal respectively disposed on the left and right side edges of one of the two common electrodes and the black mask, which are the resistance films, and the other top and bottom edges, respectively. A first switch that switches between the third terminal and the fourth terminal, the first terminal and the third terminal and connects either one to the high voltage side, and the second terminal and the fourth terminal respectively connect to the low voltage side The second terminal and the fourth terminal are switched, one of them is connected to the low voltage side via a voltmeter, and the voltage drop due to the resistance film is reduced by the second switch operating in conjunction with the first switch. A display device with a coordinate input function, comprising: the voltmeter for measurement; and coordinate position calculation processing means for obtaining a coordinate position from a value of the voltmeter. In the display device with a coordinate input function according to any one of claims 1 to 6,
The coordinate position detection means includes an upper right terminal, a lower right terminal, an upper left terminal, and a lower left terminal respectively formed at the four corners of one resistance film of the common electrode and the black mask.
A state where one pair of terminals of the right pair of upper right terminals and lower right terminals and the left pair of upper left terminals and lower left terminals are connected to the high voltage side, and the other pair of terminals are connected to the low voltage side. One of the upper pair of upper right terminals and upper left terminals and the lower pair of lower right terminals and lower left terminals is connected to the high voltage side, and the other pair of terminals is connected to the low voltage side. With a switch to switch between states
Further, a low voltage side electrode formed so as to substantially surround the other resistance film and connected to the low voltage side, a voltmeter for measuring a voltage drop due to the resistance film in the low voltage side electrode, A display device with a coordinate input function, comprising coordinate position calculation processing means for obtaining a coordinate position from a value. A liquid crystal is sealed between two transparent substrates having electrodes on the inner surface, and includes a large number of stripe-shaped signal electrodes and a large number of stripe-shaped scanning electrodes perpendicular to the signal electrodes. A display device with a coordinate input function using a simple matrix type liquid crystal display device,
Pressure-sensitive switching means formed at the intersections of these electrodes between the signal electrode and the scanning electrode, and a place where a short circuit occurs between the signal electrode and the operation electrode by the pressure-sensitive switching means And a coordinate position detecting means for detecting the voltage by sequentially applying a voltage to one of the electrodes.   Between the pair of substrates, a liquid crystal, a first resistance film having a predetermined sheet resistance, a second resistance film having a predetermined sheet resistance, and an external push between the first resistance film and the second resistance film are provided. A display device with a coordinate input function, comprising pressure-sensitive switching means having a low resistance according to pressure.

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