Patent Application
20080302583
The present invention relates to a gas cell for a touch input device such as a touch panel and a push button switch, and more particularly to a gas cell for an electrostatic induction type touch input device.
A touch input device for conducting an input by contacting a panel type keyboard with a finger is widely used with a personal computer, an automatic teller machine, a ticket vending machine and the like.
A main trend of a touch input device to date uses a resistor film.
As shown in
Patent Document 1: Japanese Patent Laid-open Publication No. HEI-8-54977
Various developments have been made for this resistor film type touch input device. A main point of technical developments is a total optical transmittance of a panel. Dot spacers are considered most adversely affecting the total optical transmittance. Dot spacers not only intercept light but also cause refraction, irregular reflection, moire stripes, which are the most significant factors of performance degradation.
However, there is a limit in improving a panel total optical transmittance of a resistor film type touch input device which has dot spacers as essential constituent elements for maintaining a gap between two plate members and retaining a stroke of the plate member.
The present invention has been made in consideration of the above-described circumstance, and it is an object of the present invention to provide a touch input device capable of improving an optical transmittance considerably without using dot spacers.
In order to achieve the above object, the present invention provides a gas cell for a touch input device comprising: a parallel plate member including two flat plates disposed in parallel and facing each other and having a plurality of electrodes; a sealing member for sealing a peripheral portion of the parallel plate member in such a manner that gas is accommodated in a gap between the two flat plates in a state that the two flat plates can conduct relative displacement along opposing directions; and a frame for holding the peripheral portion of the parallel plate member in such a manner that the two flat plates can conduct the relative displacement along opposing directions.
The present invention also provides a gas cell for an electrostatic induction type touch input device comprising: a parallel plate member including two flat plates disposed in parallel and facing each other and having a plurality of conductive wires and electrodes; a sealing member being mounted on a peripheral portion of the parallel plate member for sealing the peripheral portion of the parallel plate member in such a manner that gas is accommodated in a gap between the two flat plates in a state that the two flat plates can conduct relative displacement along opposing directions; and a frame for holding the peripheral portion of the parallel plate member in such a manner that the two flat plates can conduct the relative displacement along opposing directions.
For a touch input device such as a touch panel also called a human-machine interface, it is a matter of course that whether a touch sense during operation is bad or good is the most important issue. According to conventional techniques, this issue is apt to be disregarded, and few touch input devices can instruct a machine or instrument with satisfactorily good touch sense. The present invention realizes best touch sense by utilizing elasticity of gas. A further characteristic feature of the invention resides in that the touch sense can be adjusted freely by a simple approach.
Many touch panels such as a resistor film type touch panel use “dot spacers” of elastic polymer material in order to realize stroke and depression sense of a switch. However, dot spacers become a very large obstacle when considering the present situation that the most important issue of technical developments is a persistent pursuit of transparency. This contradiction can be overcome completely by an “air spacer” of the invention which uses gas.
Further, the present invention employs a non-contact type for each switch element constituting a number of switch groups. This non-contact type perfectly solves the problem of contact failure and temporal change which is a critical issue of switch.
Each switch element adopts an electrostatic induction method. With this method, an ON/OFF operation of a switching circuit and a selection operation of a switch position can be performed separately. Therefore, an ON/OFF mechanism can be shared by all switches independent from the number of switches (only one ON/OFF mechanism is sufficient). This condition is essential for allowing the present invention to be practically used. More specifically, a target switch in a number of matrix switch groups can be selected merely by moving a finger near to the switch. After the finger touches the switch and depresses it, an ON condition is satisfied for all switch groups. However, this condition is made invalid for the switches other than the selected switch. It is therefore judged that only the target switch is ON, and it is possible to prevent an erroneous operation to be caused by “touching wrong switch” which is one issue associated with a touch panel.
Since elasticity of gas is utilized as a spring mechanism of switch, there is a large advantage over conventional elastic materials such as rubber, polymer, and metal spring. Namely, these conventional elastic materials have essentially a limited lifetime due to material fatigue. Gas, particularly air, exists inexhaustibly and if gas can be replenished by one operation as proposed in the present invention, it is not necessary at all to consider the lifetime of switch.
A further advantage is low cost. The whole mechanism is constituted of only upper and lower transparent electrode plates and a peripheral diaphragm, realizing a quite simple and plain structure and dispensing complicated adjustment. Furthermore, since there is no fear of failure of contact points, degradation and exhaustion of constituent components and the like, there is considerable advantages in terms of manufacture cost and maintenance cost.
The invention, particularly the invention described in claim 1, can realize good touch sense by utilizing gas elasticity. Moreover, this touch sense can be freely adjusted by changing the pressure of gas loaded in the space in a plate member. Since dot spacers are not used, a touch panel having a high transparency can be realized.
Further, since switch elements constituting a number of switch groups are non-contact, problems of contact failure and temporal change will not occur. Furthermore, since a switch position can be selected and all switches share the ON/OFF mechanism, it is possible to prevent an erroneous input from other switches after one switch is selected. Moreover, the invention uses air as a spacer without using dot spacers so that a touch panel can be manufactured inexpensively.
The invention described in claim 2 can make smooth a relative displacement of a parallel plate member.
The invention described in claim 3 can facilitate a supply of air constituting the air spacer.
The invention described in claim 4 can improve a total optical transmittance of a touch panel.
The invention described in claim 5 can improve a total optical transmittance of a touch panel.
The invention described in claim 6 can facilitate to identify a switch position.
The invention described in claim 7 can improve a total optical transmittance of a touch panel.
The invention described in claim 8 can easily configure an electrostatic induction type touch panel.
The invention described in claim 9 can easily configure an electrostatic induction type touch panel in particular.
The invention described in claim 10 can easily identify the position of a switch.
The invention described in claim 11 can adjust the characteristics of a touch panel and configure the touch panel having a stable performance.
The invention described in claim 12 can realize good touch sense by utilizing gas elasticity. Moreover, this touch sense can be freely adjusted by changing the pressure of gas loaded in the space in a plate member. Since dot spacers are not used, a touch panel having a high transparency can be realized.
Further, since switch elements constituting a number of switch groups are non-contact, problems of contact failure and temporal change will not occur. Furthermore, since a switch position can be selected and all switches share the ON/OFF mechanism, it is possible to prevent an erroneous input from other switches after one switch is selected. Moreover, the invention uses air as a spacer without using dot spacers so that a touch panel can be manufactured inexpensively.
The invention described in claim 13 can make smooth a relative displacement of a parallel plate member.
The invention described in claim 14 can facilitate a supply of air constituting the air spacer.
The invention described in claim 15 can improve a total optical transmittance of a touch panel.
The invention described in claim 16 can improve a total optical transmittance of a touch panel.
The invention described in claim 17 can facilitate to identify a switch position.
The invention described in claim 18 can improve a total optical transmittance of a touch panel.
The invention described in claim 19 can easily configure an electrostatic induction type touch panel.
The invention described in claim 20 can easily configure an electrostatic induction type touch panel in particular.
The invention described in claim 21 can easily configure an electrostatic induction type touch panel.
The invention described in claim 22 can adjust the characteristics of a touch panel and configure the touch panel having a stable performance.
The invention described in claim 23 can improve a total optical transmittance of a touch panel.
The invention described in claim 24 can improve a total optical transmittance of a touch panel by using a mold of indium oxide ultra fine particle powder excellent in transparency.
The invention described in claim 25 can configure a touch panel capable of preventing input of external disturbance and conducting a precise operation by forming a shield layer.
The invention described in claim 26 can configure a touch panel capable of preventing interference between conductive wires and conducting a precise operation.
The invention described in claim 27 can configure a touch panel capable of facilitating mounting a diaphragm, realizing reduction in manufacture cost and providing reliable air tightness.
The invention described in claim 28 can configure a touch panel capable of facilitating supply of air between two flat plates.
The invention described in claim 29 can configure an electrostatic induction type touch panel capable of preventing erroneous input operation.
Embodiments of the present invention will now be described with reference to the accompanying drawings. First, the first embodiment will be described.
In
The peripheral portion of the parallel plate member 2 is fitted in a frame 7 at the outside of the diaphragm 5. For example, the frame is made of aluminum die-cast or plastic.
A stopper 8 is disposed between the parallel plate member 2 and frame 7 to regulate the range of relative displacement between the flat plates 3 and 4. Gas to be filled in the gap 6 may be air. The gas is supplied into the gap 6 by a gas supply unit 11. The gas supply unit 11 has a pipe 12, a valve 13 and a controller 14. The valve 13 is opened by a signal from the controller 14 so that air can be introduced from the pipe 12 into the gap 6. The valve 13 and controller 14 may be replaced with a rubber valve.
As shown in
Two flat plates 3 and 4 of the parallel plate member 2 are made of transparent material such as glass and plastic, and the drive electrode 17 and detector electrode 18 are also made of transparent material. For example, the reflection electrode 15, drive electrode 17 and detector electrode 18 may be formed by sputtering indium oxide. In order to shield the input/output electrodes 16 disposed on the other flat plate 4 along row and column directions, shielding is effected on the whole surface of the one flat plate 3 with the reflection electrodes 15, excepting the window-shaped surface where the reflection electrodes are formed.
Common connection wirings at each row and column of the other flat plate 4 are led to an external and connected to a high frequency signal source and a reception unit. The operation of the gas cell 1 for a touch input device constructed as above is as follows.
As a finger comes near to each reflection electrode during a touch input operation, a portion of high frequency current drains to the earth via the finger 21 so that a reception signal level at the corresponding detector electrode changes toward a negative direction (a change in
In this embodiment, a deflection amount of a plate glass used as the upper movable plate (flat plate 3) shown in
As shown in
In the case of a uniformly distributed load on four-side supported rectangle plate,
σc=β1(W·a2)/t2 (1)
εc=α:(W·a4)/(E·τ3) (2)
A white circle symbol ◯ in
A mass of plate glass is calculated for W and P excepting that a load is applied along a horizontal direction.
Refer to Table 1 for coefficient values.
σc, σc: maximum bending stress (MPa) at plate center and side center of plate glass
δc, δc: maximum deflection (mm) at plate center and side center of plate glass
a: length of shorter side of rectangle, radius of circle, or free side length of two-side or three-side supported rectangle (mm)
b: length of longer side of rectangle, or support side length of two-side or three-side supported rectangle (mm)
t: thickness of plate glass (mm)
W: uniformly distributed load (MPa)
P: concentrated load
β1 to β4: coefficient determined by side length ratio b/a
α1 to α4: coefficient determined by side length ratio b/a
E: Young's modulus of plate glass 7.16×104 (MPa)
Equation (2) was used for calculating deflection δ.
Rectangular plate glass was assumed having a shorter side a of 200 mm and a longer side b of 300 mm
First, a deflection amount per pressure of 1 gr/cm2 is calculated.
The above constants are substituted in Equation (2):
δ=0.088×(0.0001×2004)/(7.16×104×0.73)=0.572 mm
Next, a dead weight of glass plate per 1 cm2 is calculated.
plate thickness 0.7 mm=0.07 cm
specific gravity=2.5
dead weight ω=0.07×2.5=0.175 gr/cm2
Since resistance of the diaphragm can be neglected relative to ω, deflection appears first at W>ω when plate glass abuts on the stopper 6 shown in
This is plotted as the graph shown in
0.175×20 cm×30 cm=105 gr.
According to the Boyle-Charles' law, the reaction force increases as the plate glass is pushed further so that proper depression sense can be obtained. In this state, the upper flat plate 3 moves downward away from the stopper 8, and the deflection given by Equation (2) will not appear. If liquid is used as fluid to be filled in the gap, deflection will not appear so that it is not necessary to consider this point.
If the upper movable plate (flat plate 3) has deflection due to the pressure of sealed gas during touch input, the operation of each switch is hindered. In order to avoid this, it is essential that the upper movable plate (flat plate 3) is moved downward away from the stopper 8 while the upper movable plate (flat plate 3) is depressed. Therefore, the requisites of this invention are to depress the upper movable plate (flat plate 3) until it becomes away from the stopper.
Next, description will be made on the second embodiment.
In
The peripheral portion of the parallel plate member 2b is fitted in a frame 7b at the outside of the diaphragm 5b to allow displacement of the flat plate 3b. For example, the frame 7b is made of aluminum die-cast or plastic.
A stopper 8b is disposed between the parallel plate member 2b and frame 7b to regulate the range of relative displacement between the flat plates 3b and 4b. Gas to be filled in the gap 6b may be air. The gas is supplied into the gap 6b by a gas supply unit 11b. As shown in
As shown in
The flat plate 4b constitutes a board 53b which is fixed to a display device 51b via the frame 7b to be described later. The flat plate 3a constitutes a touch board 54b which is an input touch operation target and can move toward the board 53b.
An outer surface of the flat plate 3b constituting the touch board 54b is covered with a shield layer 55b. Since a non-shielding window 56b is formed through the shield layer 55b at a position corresponding to the reflection electrode, the shield layer does not exist at the position corresponding to the window 56b.
The input/output electrode on the flat plate 4b constituting the board 53b is constituted of a pair of the drive electrode 17b and detector electrode 18b. Drive electrodes of respective pairs and conductive wires 31b connecting these electrodes are formed on one of the inner or outer surfaces of the flat plate 4b, in this embodiment, on the outer surface, whereas detector electrodes of respective pairs and conductive wires 32b connecting these electrodes are formed on the other surface, in this embodiment, on the inner surface. Conductive wires connecting the drive electrodes will not therefore be interfered with conductive wires connecting the detector electrodes.
These electrodes and conductive wires are made of nano material. Nano material utilizes a phenomenon that if material such as metal is changed to ultra fine particle powders (nanometer nm in diameter), the quality of material changes quite differently. For example, if indium oxide as transparent electrode material is changed to fine powders, ideal transparent electrode material can be obtained which has a transparency of near 100% and electric resistance value of infinitely zero. Since the present invention aims at realizing an optical transparency of near 100% by using air spacer, it is very effective to use electrode material having a high transparency.
This advantage is not applied to a low transparency type. In this embodiment, electrodes and conductive wires are made of mold of indium oxide ultra fine particle powders.
The operation of the gas cell 1b for a touch input device constructed as above is as follows.
As shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2004-280019 | Sep 2004 | JP | national |
| 2005-276465 | Sep 2005 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP05/18236 | 9/27/2005 | WO | 00 | 2/1/2008 |
