JPH0546306A - Coordinate input device - Google Patents

Abstract

PURPOSE:To constitute the device so that an input coordinate can be detected with high precision, and also, an erroneous input is not executed by pressure of the palm by connecting electrically two pieces of opposed conductive films only when they are pressurized by a cordless exclusive input jig. CONSTITUTION:The device is provided with a first and a second conductive films 14, 12 in which each of them has a uniform resistance distribution, and at least one of them is formed on a flexible substrate, and also, which are placed so as to be opposed to each other, and an insulating film 13 which is interposed and placed between a first and a second conductive films 14, 12, and insulates between a first and a second conductive films 14, 12. In such a state, only when a first conductive film 14 is pressurized by a cordless exclusive input jig 18, the electric connection of a first and a second conductive films 14, 12 is executed through an opening 17 of the insulating film 13. Accordingly, since the insulating film 13 for selecting a pressurizing means is provided, by the pressure of the palm, etc., in whick an area of a pressurizing part is larger than the exclusive input jig 18, the electric connection of a first and a second conductive films 14, 12 cannot be executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device, and more particularly, to an input / output device for handwriting input which is superposed on the display surface of a display device such as a liquid crystal display device so that the display position corresponds to the position of the input device. The present invention relates to a coordinate input device suitable for a body type device.

[0002]

2. Description of the Related Art A coordinate input device for displaying input position coordinates on a display surface of a display device has conventionally been arranged such that two transparent substrates having a transparent conductive film are opposed to each other via a dot spacer, and the two transparent substrates are opposed to each other. There is known a membrane touch panel in which the transparent substrate is electrically connected only when pressure is applied (for example, US Pat. No. 3,911,215 and US Pat. No. 4,484,038).

FIG. 5 is a block diagram showing an example of a conventional device disclosed in US Pat. No. 3,911,215. In the figure,
A point electrode 32 is provided in the case 31, and a conductive film (resistive film) 33 and a flexible conductive film 35 having a protrusion 34 are arranged opposite to the point electrode 32. Furthermore, the flexible conductive film 35
A protective film 36 is provided on the top.

In such a conventional device (membrane / touch panel), the conductive films 33 and 35 are not in contact with each other by the projection 34, but when a desired position on the protective film 36 is pressed by the pen 37, the flexible film is flexible. The conductive conductive film 35 is deformed and comes into contact with the conductive film 34.

In this state, the reference voltage is applied in a time division manner, and the contact position coordinates are detected by the potential of the contact position. Since this membrane touch panel can be formed without patterning the conductive film, it has advantages that it is easy to manufacture, it is low in cost, and the pressure input means can be a finger, and operability is easy.

Further, conventionally, a capacitive coupling type input panel is known as a coordinate input device having high position accuracy (for example, JP-A-63-13115 and JP-A-63-1).
No. 42415). This capacitively coupled input panel inputs position coordinates by the charge accumulated in the capacitor formed between the electrode on the input panel and the electrode provided at the tip of the dedicated stylus pen connected to the input panel body with a cord. It is a configuration that does.

FIG. 6 is a block diagram showing another example of the conventional coordinate input device disclosed in Japanese Patent Laid-Open No. 63-142415. In the figure, the glass substrates 41 and 42 are stacked via a transparent resistor 43 formed on the lower surface of the glass substrate 41 and a transparent resistor 44 formed on the upper surface of the glass substrate 42.

Further, electrodes 45 and 46 are formed on both ends of the lower surface of the glass substrate 41 in the X-axis direction. Electrodes 47 and 48 are formed on both ends of the upper surface of the glass substrate 42 in the Y-axis direction. A gap portion G is formed in the resistor 43. A detection electrode 49 is placed on the upper surface of the glass substrate 41.

In this structure, when the X coordinate of the position of the detection electrode 49 is obtained, the switch 50 is set to the contact S side.
Also, the switches 51, 52 and 53 are closed on the contact E side, respectively. As a result, the signal from the signal source 54 flows between the electrodes 45 and 46, capacitive coupling occurs between the detection electrode 49 and the opposing portion of the resistor 43, and the potential between the electrodes 45 and 46 is detected. ..

The potential of the detection electrode 49 is the peak detection circuit 55.
And the A / D converter 56, respectively, to obtain the first X coordinate data. Next, the switch 50 is switched to the contact E and the switch 51 is switched to the contact S, respectively.
The potential generated at 9 is taken out as the second X coordinate data through the peak detection circuit 55 and the A / D converter 56, respectively.
Then, the true X coordinate data is obtained from the first and second X coordinate data.

To obtain the Y coordinate of the position of the detection electrode 49, the switch 52 is closed on the contact S side and the other switch 5 is closed.
0, 51, and 53 are closed on the contact E side, respectively, and the detection electrode 4
9 and the data when the capacitive coupling is generated between the resistor 9 and the opposing portion of the resistor 44 via the gap G, and the data when the switch 52 is switched to the contact E and the switch 53 is switched to the contact S side. And ask from. The detection electrode 49 is provided on the tip of a dedicated stylus pen (not shown).

In the conventional capacitively coupled input panel described in the above-mentioned Japanese Patent Laid-Open No. 63-13115, a voltage is applied in a pulsed manner, the electric charge discharged at that time is detected by a current, and then a power supply voltage is applied. A “discharge current detection method” is used in which the position coordinates are detected by conversion.

[0013]

However, in the conventional device as shown in FIG. 5, the indium tin oxide (ITO) or tin dioxide (SnO ₂ ) doped with tin is used as the conductive film on the transparent substrate. Since the transparent conductive film vapor-deposited on is used, there is a variation in the sheet resistance of about 10% within the surface.

In this case, for example, 200 mm × 130 mm
On the input surface, the maximum displacement is 20 mm, which cannot be used for figure input. In addition, when inputting with the pen, if a portion other than the pen, such as the palm, presses the touch panel, there is a problem that the normal position of the pen tip cannot be detected.

Further, in the conventional device of the capacitive coupling type as shown in FIG. 6 and the like, although a high position accuracy of 0.1 mm is obtained, a dedicated stylus pen is connected to the input panel body by a cord. However, there is a problem that the operability is limited by the code.

Further, in the structure of the dedicated stylus pen, in order to reduce the influence of noise from the outside, the pen housing must be shielded and an amplifier circuit must be built in, and the pen becomes heavy and thick. .. Further, the cord connecting the pen and the input panel needs a shield in order to reduce the influence of noise from the outside, and therefore the cord also becomes thick.

The present invention has been made in view of the above points,
An object of the present invention is to provide a coordinate input device that solves the above-mentioned problems by configuring two opposing conductive films to be electrically connected only when pressed by a cordless dedicated input jig. ..

[0018]

In order to achieve the above-mentioned object, the present invention, as described in claim 1, has a uniform resistance distribution, at least one of which is formed on a flexible substrate. Along with the first and second conductive films arranged to face each other, openings are regularly formed, and the first and second conductive films are interposed between the first and second conductive films. An insulating film for insulating between the conductive films, and only when the first conductive film is pressed by a cordless dedicated input jig, the first and second conductive films are opened through the opening of the insulating film. It is intended to electrically connect the membranes.

Further, according to the present invention, as described in claim 2, DC voltages which are orthogonal to each other are alternately applied to the first and second conductive films, and one of the conductive films is used as a detection electrode to take out coordinate output. A detection means is provided.

Further, the first and second conductive films each have a quadrilateral plane, and DC voltage applying electrodes are formed on two sides orthogonal to the substrate moving direction during film formation.

Further, according to the present invention, the detecting means includes a switching element for applying or blocking a reference voltage to the first conductive film via a current limiting resistor.

Further, according to the present invention, the transmittance of the substrate on which the first and second conductive films and the insulating film are formed is 50% or more in the visible light wavelength region.

[0023]

According to the first aspect of the present invention, since the insulating film for selecting the pressing means is provided, depending on the pressure applied by the palm or the like, the area of the pressing part is larger than that of the dedicated input jig, the first and second The electrical connection between the conductive films can be prevented. Further, since the dedicated input jig is cordless, no noise reduction structure like the dedicated stylus pen of the capacitive coupling type conventional device is required.

Further, in the detecting means according to the second aspect of the present invention, a potential drop is generated in a state where the first and second conductive films are electrically connected through the opening of the insulating film. A DC voltage is applied to one of the conductive films, and the potential of the electrical connection point in the X direction is detected by the opposing conductive film.

Next, the detection means applies a DC voltage to the other conductive film so as to cause a voltage drop in a direction perpendicular to the voltage drop of the DC voltage, and the one conductive film makes an electrical connection point. The electric potential in the Y direction is detected. Thereby, the position coordinates of the pressure point can be calculated.

According to the third aspect of the present invention, since the DC voltage applying electrodes are arranged on two sides of the conductive film in the direction orthogonal to the substrate moving direction when the conductive film is formed, the DC voltage of the conductive film is reduced. It is possible to match the direction of the potential drop of the voltage with the direction in which the variation of the sheet resistance is small.

Further, in the invention according to claim 4, the reference voltage is applied to the first conductive film which is electrically connected to the second conductive film through the switching element and the current limiting resistor, After detecting that the potential of the first conductive film has become equal to or lower than a certain value, the reference voltage is cut off by the switching element, so that the influence of the voltage detection by the current limiting resistor can be eliminated.

Further, in the invention according to claim 5, the first
Since the substrate on which the second conductive film and the insulating film are formed can be made substantially transparent, the opposite direction can be seen through from the first conductive film side.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partially cutaway perspective view of the essential part of one embodiment of the present invention. In the figure, a transparent conductive film 12 is deposited on a transparent glass substrate 11. An insulating film 13, a transparent conductive film 14, and a transparent insulating substrate 15, which will be described later, are sequentially laminated on the transparent conductive film 12.

The transparent insulating substrate 15 is flexible such as polyethylene terephthalate (PET) or polyester sulfone (PES) from the viewpoint of good transmittance in the visible light wavelength region and excellent heat resistance. It is composed of a flexible film substrate. The transparent conductive film 14 is vapor-deposited on the surface of the transparent insulating substrate 15.

The transparent conductive films 12 and 14 are made of ITO, SnO ₂ or zinc dioxide (Zn) in consideration of the transmittance and heat resistance in the visible light wavelength region as described above.
A transparent conductive film such as O ₂ ) is used. This transparent conductive film 1
Nos. 2 and 14 are DC sputtering devices in an oxygen flow, respectively, and have a specific resistance of 5 × 10 ⁻⁴ (Ω · c) under known film forming conditions.
m) A film having a uniform resistance distribution of m or less is formed by vapor deposition on the transparent glass substrate 11 and the transparent insulating substrate 15.

As shown in FIG. 2, the transparent conductive films 12 and 14 have quadrilateral planes, and the DC voltage applying electrodes 21 and 22, and 23 and 24 are Ag paste and carbon paste on two opposite sides, respectively. Is formed by screen printing followed by heat treatment. However, in this embodiment, as will be described later, the electrodes 21 and 22, 23 and 24 are provided at predetermined positions.

Next, the insulating film 13 is formed on the transparent conductive film 12. As a forming method, for example, screen printing is used, and it is desirable that the material of the insulating film is a resin containing a thermosetting silicone resin or an ultraviolet curing urethane resin.

Further, circular openings 17 are regularly formed in the insulating film 13. The radius and thickness of the opening 17 of the insulating film 13 are set so that the transparent conductive films 12 and 14 contact each other through the opening 17 by the pressure applied by the dedicated input jig 18 and do not contact by the pressure applied by the palm. It is set in consideration of the radius of the tip of the dedicated input jig 18 and the Young's modulus (thickness) of the transparent insulating substrate 15.

As an example, the radius of the tip of the dedicated input jig 18 is 0.25 mm and the radius of the opening 17 of the insulating film 13 is 240 μm.
The thickness of the insulating film 13 is set to 5 μm. The dedicated input jig 18 is cordless and has a small and lightweight structure that can be manually operated.

As a result, the transparent conductive films 12 and 14 are not blocked by the non-opening portion of the insulating film 13 and are not in contact with each other when the surface pressure is applied by the palm, but the transparent conductive films 12 and 14 are opened only when pressure is applied by the tip of the dedicated input jig 18. The transparent conductive films 12 and 14 are in contact with each other through 17. Therefore, when characters or the like are input using the dedicated input jig 18, normal coordinates can be detected even if the input surface is pressed by the palm.

Finally, after the transparent conductive film 14 formed by vapor deposition on the flexible transparent insulating substrate 15 is placed on the insulating film 13, the double-sided adhesive tape 16 is used to bond the transparent glass substrate 11 and the transparent insulating substrate 15. The peripheral parts are fixed by adhesion.

In the coordinate input device thus produced, the transmittance from the transparent glass substrate 11 to the transparent insulating substrate 15 is 50% or more in the visible light wavelength region. Thereby, for example, the coordinate input device is arranged so that the transparent glass substrate 11 is placed on the display surface of the liquid crystal display device, and the input / output integrated device can be configured.

Next, as shown in FIG. 2, electrodes 2 for applying a DC voltage are applied to the transparent conductive films 12 and 14 having a quadrilateral planar shape.
The formation positions of 1, 22, 23, and 24 will be described. The transparent conductive films 12 and 14 are a direct-current sputtering device in an oxygen flow, and are ITO while translating the substrates 11 and 15.
Shall be formed into a film.

In this case, a 25-inch wide In-Sn (10 wt%) wide enough as a sputtering target
A flexible film substrate such as 600 mm wide roll-shaped PET is provided with a mechanism capable of reciprocating parallel movement in a direction perpendicular to the longitudinal direction of the target using 10% O ₂ -90% Ar.
An ITO film is formed with a gas flow rate of 50 sccm, a reaction gas pressure of 7 × 10 ⁻³ Torr, and a DC voltage of 90 W.

It has been confirmed by experiments that the sheet resistance of the ITO film (that is, the transparent conductive film 12 or 14) in this case is as shown in FIG. 3 and the variation of the sheet resistance is as shown in FIG.

As can be seen from FIG. 3, in the range of ± 150 mm from the center of the direction perpendicular to the moving direction of the transparent insulating substrate having a width of 600 mm (that is, the y direction is the width direction), the ITO film The sheet resistance ρ varies from about 60 Ω / □ to about 90 Ω / □, and the variation of the sheet resistance in the y-axis direction is about ± 25%.

On the other hand, as can be seen from FIG. 3, in the range of ± 150 mm from the center in the y-axis direction, the x-axis direction (that is, the direction parallel to the moving direction of the transparent insulating substrate).
Position of 50mm, 100mm, 150mm, 200mm, 25
It can be seen that the sheet resistance shows substantially the same value if the position in the y-axis direction is the same even if the position is changed to 0 mm.

Therefore, when the sheet resistance at the same location is repeatedly measured a plurality of times to calculate the variation in the sheet resistance, it becomes as shown in FIG. As can be seen from FIG. 4, within a range of ± 150 mm from the center in the y-axis direction, the variation in the sheet resistance at each point in the x-axis direction is the accuracy of the measuring device (± 0.5 mm).
%) Or less.

Therefore, the present inventor pays attention to the above experimental result, and the electrodes 21 are formed on two opposite sides which are orthogonal to the moving direction (shown by A in FIG. 2) of the substrate 11 when the transparent conductive film 12 is formed. ，
22 are formed respectively, and similarly, electrodes 23 and 24 are formed on two opposite sides orthogonal to the moving direction of the substrate 15 (shown by B in FIG. 2) when the transparent conductive film 14 is formed.

As a result, the transparent conductive films 12 and 14 are
In both cases, since the voltage drop of the applied DC voltage occurs in the direction in which the sheet resistance variation is ± 0.5% or less and matches the substrate moving directions A and B (x-axis direction), the positional accuracy on the electrodes 21 to 24 is ±. High accuracy of 0.5% or less can be achieved.

Next, the detection means for extracting the coordinate detection signal of this embodiment will be described with reference to FIG. The transparent conductive film 12 on which the DC voltage applying electrodes 21 and 22 are formed on the two sides facing each other and the transparent conductive film 14 on which the DC voltage applying electrodes 23 and 24 are formed on the two sides facing each other , Are arranged as shown in FIG. 2 so that the DC voltage drop directions are orthogonal to each other. This is for detecting the two-dimensional coordinate position of the x coordinate position and the y coordinate position.

The electrode 21 is connected to the reference voltage Vcc, which is the power supply voltage on the high potential side, through the collector and emitter of the PNP transistor Tr1. The electrode 22 is connected (grounded) to the ground potential, which is the low-potential-side power supply voltage, via the collector and emitter of the NPN transistor Tr2.

The electrode 23 is connected to the reference voltage Vcc via the collector and emitter of the PNP transistor Tr3, and the electrode 24 is grounded via the collector and emitter of the NPN transistor Tr4. Further, the PNP transistor Tr5, which is a switching element, has a collector with a current limiting resistor R
_It is connected to the electrode 23 via ₁ and the reference voltage Vcc is applied to its emitter.

A pulse from a control circuit (not shown) is applied to the bases of all the transistors Tr1 to Tr5, and the transistors Tr1 to Tr5 perform a switching operation independently of each other, so that the transparent conductive films 12 and 14 are alternately applied with a DC voltage. Is applied, and the detection voltage corresponding to the contact position of both transparent conductive films 12 and 14 is obtained using the transparent conductive film to which the DC voltage is not applied as the detection electrode.

Next, the transistors Tr1 to Tr5 and the resistor R
_The detection operation by ₁ will be described. First, the transistors Tr2 and Tr5 are turned on, and the transistors Tr1, Tr3 and T5 are turned on.
Each r4 is controlled off. As a result, the reference voltage Vcc
There emitter of the transistor Tr5, a collector, is applied to resistor R ₁ respectively via the electrode 23. At the same time, the electrode 22 is set to the ground potential via the transistor Tr2.

Therefore, at this time, by selecting the resistance value of the resistor R ₁ to be sufficiently larger than the total sheet resistance values of the transparent conductive films 12 and 14, the pressure applied by the dedicated input jig 18 causes the transparent conductive film 12 and When 14 contact each other, the potential V _{SENSEX at} the connection point between the resistor R ₁ , the collector of the transistor Tr3 and the electrode 23 becomes substantially the ground potential.

When the contact between the transparent conductive films 12 and 14 is confirmed by _setting V _SENSEX to the ground potential, then the transistors Tr3 and Tr4 are turned on and the transistor T is turned on.
r1, Tr2 and Tr5 are turned off respectively.

As a result, the reference voltage Vcc is applied to the electrode 23 via the emitter and collector of the transistor Tr3, the electrode 24 is set to the ground potential via the transistor Tr4, and the DC voltage Vcc is applied to the transparent conductive film 14. To be done.

As a result, the DC voltage reduced by a voltage drop corresponding to the position coordinate in the X direction of the contact position between the transparent conductive films 12 and 14 is transmitted to the electrode 21 and the collector of the transistor Tr1 via the transparent conductive film 14. Detection voltage V from the connection point
_It is taken out as _SENSEY .

Since the transistor Tr5 is turned off, the electrical connection between the resistor R ₁ and the electrode 23 is cut off.
It is possible to eliminate the influence of potential detection by the resistor R ₁ .

Subsequently, the transistors Tr1 and Tr2 are respectively
ON, transistors Tr3, Tr4 and Tr5 are OFF respectively.
Be done. Thereby, the reference voltage V is applied between the electrodes 21 and 22.
cc is applied. Contact position between the transparent conductive films 12 and 14
Is the transparent conductivity of the one to which Vcc which is DC voltage is applied.
The electric potential of the membrane 12 is generated, and this electric potential is
Through the transparent conductive film 14 to which no flowing voltage is applied
Detection voltage V from electrode 23 _SENSEXIs taken out as.

Therefore, the detected voltage V _SENSEX is a _divided voltage of the reference voltage which is dropped according to the position of the contact position between the transparent conductive films 12 and 14 in the Y direction. This allows
From the above-described detection voltage V _{SENSEY and} this detection voltage V _SENSEX , the contact position between the transparent conductive films 12 and 14, that is, the input coordinate position can be calculated.

In the present embodiment, the variation in sheet resistance in the direction of voltage drop of the transparent conductive films 12 and 14 is set to 1% or less, so that a high resolution of 10 times or more as compared with the conventional membrane touch panel can be obtained. realizable.

[0060]

As described above, according to the invention described in claim 1, since the insulating film is provided with the function of discriminating the pressing means, the palm is also used for the input surface when the coordinate is input by the dedicated input jig. Since the input position can be normally detected, and the dedicated input jig does not need to be cordless and has no noise reduction structure, the dedicated input jig can have a lightweight, small-sized and extremely easy-to-operate structure.

According to the second aspect of the invention, a detection signal of the input coordinate position can be obtained by the coordinate input device having the insulating film. According to the third aspect of the invention, the direct current of the conductive film is Since the direction of the voltage drop of the voltage can be made to coincide with the direction in which the variation in the sheet resistance is small, it is possible to configure a resolution that is 10 times or more higher than that of the conventional membrane touch panel.

Further, according to the invention of claim 4, since the influence of the voltage detection by the current limiting resistor can be eliminated, it is possible to detect the input position coordinates with high accuracy, and according to the invention of claim 5, the whole apparatus can be detected. Since it can be made substantially transparent, it has a feature that it can be applied to an input / output integrated device for handwriting input in which the display position and the input position are associated with each other by overlapping on the display surface of the display device.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of an essential part of an embodiment of the present invention.

FIG. 2 is a configuration diagram of another main part of an embodiment of the present invention.

FIG. 3 is a diagram showing a sheet resistance value of a transparent conductive film.

FIG. 4 is a diagram showing variations in sheet resistance of transparent conductive films.

FIG. 5 is a configuration diagram of a conventional example.

FIG. 6 is a configuration diagram of another conventional example.

[Explanation of symbols]

11 transparent glass substrate 12 transparent conductive film (second conductive film) 13 insulating film 14 transparent conductive film (first conductive film) 15 transparent insulating substrate 16 adhesive tape 17 opening 18 dedicated input jigs 21-24 for applying DC voltage Electrode Tr1, Tr3, Tr5 Switching PNP transistor Tr2, Tr4 Switching NPN transistor R ₁ Current limiting resistor

Claims (5)

[Claims] 1. A first and a second conductive film (14, 12) each having a uniform resistance distribution, at least one of which is formed on a flexible substrate, and which are arranged to face each other, and a rule. An opening (19) is formed, and is interposed between the first and second conductive films (14, 12) to insulate the first and second conductive films (14, 12). Cordless dedicated input jig (1
Only when the first conductive film (14) is pressed in 8), the electrical conductivity of the first and second conductive films (14, 12) is increased through the opening (17) of the insulating film (13). Input device characterized by performing physical connection. 2. The first and second conductive films (14, 1)
Characterized in that a DC voltage is applied perpendicular to each other in 2) alternately, detection means for extracting the coordinates output as the conductive film detection electrodes towards which the DC voltage is not applied (Tr1～Tr5, provided R ₁₎ The coordinate input device according to claim 1. 3. The first and second conductive films (14, 1)
In 2), each of the planes is a quadrilateral, and the DC voltage applying electrode (2) is provided on two sides orthogonal to the substrate moving direction during film formation of the conductive film.
3, 24 ,: 21, 22) are formed. 4. The detection means (Tr1 to Tr5, R ₁ ) is
It said first conductive film (14) to a current limiting resistor (R ₁₎ coordinate input device according to claim 2, characterized in that it comprises a switching element (Tr5) for applying or shutting off the reference voltage through. 5. The first and second conductive films (14, 1)
2) and the transmittance of the substrate on which the insulating film (13) is formed are
The coordinate input device according to claim 1, wherein the visible light wavelength region is 50% or more.