U.S. patent application number 09/918184 was filed with the patent office on 2002-05-02 for detection device in which output varies with amount by which elastically deformable contact element is pressed.
This patent application is currently assigned to Alps Electric Co., Ltd.. Invention is credited to Furudate, Toshio, Maeda, Ryoichi.
Application Number | 20020050918 09/918184 |
Document ID | / |
Family ID | 18723209 |
Filed Date | 2002-05-02 |
United States Patent
Application |
20020050918 |
Kind Code |
A1 |
Furudate, Toshio ; et
al. |
May 2, 2002 |
Detection device in which output varies with amount by which
elastically deformable contact element is pressed
Abstract
A first resistive element and a second resistive element are
serially connected to each other, and a contact element having a
lower resistivity than the first resistive element elastically
contacts the first resistive element. The resistance between both
ends of the first resistive element varies with the contact area
between the first resistive element and the contact element. When a
predetermined voltage is applied to the first and the second
resistive elements, an output voltage, which corresponds to the
resistance ratio of the first resistive element to the second
resistive element, is obtained from a conductive pattern. When the
resistance ratio of the first resistive element to the second
resistive element is set in the range of 1 to 3, the linearity is
improved and a wide variation range of the output voltage is
obtained.
Inventors: |
Furudate, Toshio;
(Fukushima-ken, JP) ; Maeda, Ryoichi; (Miyagi-ken,
JP) |
Correspondence
Address: |
Brinks Hofer Gilson & Lione
P.O. Box 10395
Chicago
IL
60610
US
|
Assignee: |
Alps Electric Co., Ltd.
|
Family ID: |
18723209 |
Appl. No.: |
09/918184 |
Filed: |
July 30, 2001 |
Current U.S.
Class: |
338/47 |
Current CPC
Class: |
G01L 5/22 20130101 |
Class at
Publication: |
338/47 |
International
Class: |
H01C 010/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 31, 2000 |
JP |
2000-230220 |
Claims
What is claimed is:
1. A detection device, comprising: a first resistive element; a
second resistive element which is serially connected to the first
resistive element; and a contact element which is elastically
deformable and has a smaller resistivity than the first resistive
element, wherein, when the contact element is pressed against a
first resistive element, a contact area between the contact element
and the first resistive element varies in accordance with the
pressing force, wherein a predetermined voltage is applied to the
first resistive element and the second resistive element, and a
detection value is given from the potential between the first
resistive element and the second resistive element, and wherein a
resistance ratio of the first resistive element to the second
resistive element (resistance of the first resistive
element/resistance of the second resistive element) is 3 or
less.
2. A detection device according to claim 1, wherein the resistance
ratio (resistance of the first resistive element/resistance of the
second resistive element) is 1 or more.
3. A detection device according to claim 1, wherein the contact
element is provided to an operation button which projects outward
from a casing and which can be pressed inward, and wherein a
detection output is obtained in accordance with the contact area
between the contact element and the first resistive element which
varies when the operation button is pressed.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a detection device which
includes an elastically deformable contact element and in which
detection output varies with the amount by which the contact
element is pressed.
[0003] 2. Description of the Related Art
[0004] Input units of game controllers, etc., contain detection
devices for obtaining detection outputs which correspond to input
operations using operation buttons. Some detection devices detect
only an ON-OFF operation, and in other detection devices, the
detection outputs vary with the amounts by which the operation
buttons are pressed.
[0005] Such detection devices, in which the detection outputs vary
with the amounts by which the operation buttons are pressed, are
constructed as follows. That is, a resistive element formed of a
resistive material having a relatively high resistivity is disposed
on a substrate, and an elastically deformable element formed of a
resistive material having a lower resistivity than the resistive
element is used as a contact element for contacting the resistive
element.
[0006] When the contact element having a relatively low resistivity
is pressed against the resistive element having a relatively high
resistivity and the contact area therebetween is changed, the total
resistance of the resistive element and the contact element is also
changed. Accordingly, the detection output is also changed.
[0007] In the case in which a game apparatus, etc., contains such a
detection device as described above and is controlled based on the
detection output, the total resistance preferably varies linearly
with the contact area when the contact element is pressed. In
addition, it is necessary to make a variation range of the
detection output, in which the detection output varies with the
contact area between the resistive element and the contact element,
as wide as possible. However, the linearity of the resistance
variation and the variation range of the detection output
contradict each other; when the linearity is improved, the
variation range is reduced, and when the variation range is
increased, the linearity is degraded.
[0008] In addition, in the case in which current is applied to the
resistive element and the variation of the contact area between the
resistive element and the contact element is determined based on a
voltage variation, the detection output is affected by resistance
variation caused due to temperature variation of the environment.
In addition, when multiple detection devices are manufactured, the
detection output is also affected by the differences in resistances
of the resistive elements which occur in the manufacturing
process.
SUMMARY OF THE INVENTION
[0009] Accordingly, in order to solve the above-described problems,
it is an object of the present invention to provide a detection
device in which the linearity is improved and a wide variation
range is obtained, and in which the detection output is not
affected by the temperature variation, etc., in the
environment.
[0010] According to the present invention, a detection device
includes a first resistive element; a second resistive element
which is serially connected to the first resistive element; and a
contact element which is elastically deformable and has a smaller
resistivity than the first resistive element. When the contact
element is pressed against a first resistive element, a contact
area between the contact element and the first resistive element
varies in accordance with a pressing force. A predetermined voltage
is applied to the first resistive element and the second resistive
element, and a detection value is given from the potential between
the first resistive element and the second resistive element. In
addition, a resistance ratio of the first resistive element to the
second resistive element (resistance of the first resistive
element/resistance of the second resistive element) is 3 or
less.
[0011] Preferably, the resistance ratio (resistance of the first
resistive element/resistance of the second resistive element) is 1
or more.
[0012] According to the present invention, the second resistive
element has a fixed resistance, and the detection output is
determined by obtaining a resistance variation, which is caused
when the contact element contacts the first resistive element,
based on the variation of the ratio of the variable resistance to
the fixed resistance.
[0013] It is not necessary that the second resistive element be
formed of a single resistor; it may be formed of a plurality of
resistors which are connected in either a parallel or serial
manner. In addition, the first resistive element may also include a
plurality of resistors which are connected in either parallel or
serial manner, and the resistors may be individually provided with
contact elements for contacting the resistors.
[0014] The contact element may be provided to an operation button
which projects outward from a casing and which can be pressed
inward, and a detection output may be obtained in accordance with
the contact area between the contact element and the first
resistive element which varies when the operation button is
pressed.
[0015] According to the present invention, the detection device in
which the detection output varies with the amount by which the
contact element is pressed is obtained. In addition, the detection
output has an improved linearity and high resolution, and the
operability is not degraded.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a perspective view of a detection device according
to an embodiment of the present invention;
[0017] FIG. 2 is a sectional view of a controller in which the
detection device is installed;
[0018] FIG. 3 is a circuit diagram of the detection device; and
[0019] FIG. 4 is a graph showing the relationship between a contact
area and an output voltage when a resistance ratio is changed.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0020] A detection device 10 according to an embodiment of the
present invention is shown in FIG. 1. The detection device 10 can
be installed in, for example, a controller of a game apparatus, and
used as an operation unit for controlling a car speed in a car
racing game, etc.
[0021] The detection device 10 includes a first resistive element
2a and a second resistive element 2b which are serially arranged on
a substrate 1. The first resistive element 2a and the second
resistive element 2b are formed by printing patterns thereof with a
resin, etc., containing carbon. One end of the first resistive
element 2a and one end of the second resistive element 2b are
connected to each other by a conductive pattern 3c. In addition, a
conductive pattern 3a is formed at the other end of the first
resistive element 2a, and a conductive pattern 3b is formed at the
other end of the second resistive element 2b.
[0022] A contact element 4 is retained above the first resistive
element 2a in such a manner that the contact element 4 can be
brought into contact with and be separated from the first resistive
element 2a. The contact element 4 is a conductive, elastic member
having the shape like a circular cone of which the vertex is evenly
cut off, and is formed by combining an elastic material such as
rubber, etc., and a conductive material such as carbon, etc. The
resistivity of the contact element 4 is lower than that of the
first resistive element 2a, and the conductive patterns 3a, 3b, and
3c are formed of a conductive material such as copper, silver,
etc., which has a lower resistivity than the contact element 4.
[0023] As shown in FIG. 2, the contact element 4 is retained by a
retainer 5, which is an elastic member formed of rubber, etc., and
which projects upward from the substrate 1. The retainer 5 includes
leg portions 5a which are bendable and which extend at an angle to
the periphery of the retainer 5. When the retainer 5 is pressed
down, the leg portions 5a are bent inward and the contact element 4
is lowered.
[0024] On the other hand, a housing 11 of a controller is provided
with an operation button 6, which is supported by the retainer 5 in
such a manner that the upper end thereof projects out from the
housing 11.
[0025] In the detection device 10, when the operation button 6 is
not pressed down, it is held up by the elastic force applied by the
retainer 5. Thus, the resistance between both ends of the first
resistive element 2a is the same as the resistance of the first
resistive element 2a itself.
[0026] When the operation button 6 is pressed down, the contact
element 4 moves downward against the elastic force applied by the
retainer 5, and comes into contact with the first resistive element
2a. In the detection device 10, the contact area between the
contact element 4 and the first resistive element 2a varies with
the amount by which the operation button 6 is pressed. More
specifically, when the contact element 4 is already in contact with
the first resistive element 2a and the operation button 6 is
pressed still further downward, the amount of elastic deformation
of the contact element 4 is increased in accordance with the amount
by which the operation button 6 is pressed. Thus, the contact area
between the contact element 4 and the first resistive element 2a is
also increased. Since the resistivity of the contact element 4 is
lower than that of the first resistive element 2a, the resistance
between both ends of the first resistive element 2a is reduced
along with the increase of the contact area.
[0027] In the detection device 10, the contact element 4 having a
low resistivity and the first resistive element 2a having a high
resistivity form a variable resistor shown in FIG. 3. In FIG. 3,
the variable resistor is serially connected to the second resistive
element 2b, which forms a fixed resistor. The resistance between
both ends of the first resistive element 2a, that is, the
resistance of the variable resistor, is denoted by Rv, and the
fixed resistance of the second resistive element 2b is denoted by
Rs. The first resistive element 2a is connected to the conductive
pattern 3a having a ground potential, and the second resistive
element 2b is connected to the conductive pattern 3b, which is
connected to a power supply having a voltage of Vcc. In addition,
the conductive pattern 3c, which serves as an output line, is
connected between the first resistive element 2a and the second
resistive element 2b.
[0028] The output voltage obtained from the output line, that is,
the conductive pattern 3c, can be determined as follows.
Output voltage=Vcc.times.{Rv/(Rs+Rv)}
[0029] As described above, the first resistive element 2a, from
which the variable resistance is obtained, and the second resistive
element 2b, from which the fixed resistance is obtained, are
serially connected to each other. In addition, the voltage is
applied to the first resistive element 2a and the second resistive
element 2b, and the output voltage is obtained from between the
first resistive element 2a and the second resistive element 2b.
Thus, not only Rv but also Rs varies along with the temperature,
etc., of the environment in which the detection device 10 is used.
Accordingly, the output voltage, which is determined by the ratio
of the resistances, is less affected by the changes in the
environment. In addition, even when multiple detection devices are
manufactured and the differences in resistances of the first
resistive elements 2a and the contact elements 4 occur in the
manufacturing process, the output voltage is also less
affected.
[0030] In order that the output voltage varies linearly with the
contact area between the first resistive element 2a and the contact
element 4, a resistance ratio (the resistance of the first
resistive element 2a/the resistance of the second resistive element
2b) is preferably 3 or less. In addition, in order to widen the
variation range of the output voltage relative to the variation of
the contact area and increase the resolution of the operation unit,
the resistance ratio (the resistance of the first resistive element
2a/the resistance of the second resistive element 2b) is preferably
1 or more.
EXAMPLES
[0031] Output characteristics of examples of a detection device
according to the present invention will be described below.
[0032] By using the examples of the detection device 10 shown in
FIGS. 1 to 3, the relationship between the contact area between the
first resistive element 2a and the contact element 4 and the output
voltage was determined. The result is shown in FIG. 4, in which the
horizontal axis shows the contact area between the first resistive
element 2a and the contact element 4, and the vertical axis shows
the output signal.
[0033] Three kinds of detection devices having different resistance
ratios (the resistance of the first resistive element 2a/the
resistance of the second resistive element 2b) were prepared. The
first detection device is a comparative example in which the
resistance ratio is 10, and the result obtained by this detection
device is shown by triangles in FIG. 4. The second detection device
is an example in which the resistance ratio is 3, and the result
obtained by this detection device is shown by rectangles in FIG. 4.
The third detection device is an example in which the resistance
ratio is 1, and the result obtained by this detection device is
shown by rhombuses in FIG. 4.
[0034] With respect to the comparative example in which the
resistance ratio is 10, when the contact area between the first
resistive element 2a and the contact element 4 is small, the
variation of the output voltage relative to the variation of the
contact area is also small. Thus, the output voltage does not vary
linearly with the contact area, and the linearity is degraded. In
contrast, with respect to the examples in which the resistance
ratio is 3 and 1, the relationship between the variation of the
contact area and the variation of the output voltage is close to
1:1, and the linearity is improved. However, when the resistance
ratio is made lower than 1, the variation range of the output
voltage relative to the variation of the contact area is reduced,
and the resolution of the output is degraded. Thus, the resistance
ratio is preferably in the range of 1 to 3.
* * * * *