U.S. patent application number 16/835580 was filed with the patent office on 2020-07-16 for image display device.
The applicant listed for this patent is Sharp Kabushiki Kaisha. Invention is credited to Kuniaki MATSUI.
Application Number | 20200225788 16/835580 |
Document ID | / |
Family ID | 57731069 |
Filed Date | 2020-07-16 |
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United States Patent
Application |
20200225788 |
Kind Code |
A1 |
MATSUI; Kuniaki |
July 16, 2020 |
IMAGE DISPLAY DEVICE
Abstract
An image display device including a capacitive touch switch that
performs switching by detecting a finger based on a change in
capacitance that is caused when the finger comes close to a panel,
wherein the touch switch comprises the panel, a substrate on which
an electrode for detecting capacitance is mounted, and a conductive
member corresponding to the electrode, and the conductive member is
provided between the panel and the electrode, and is fixed by being
interposed between the panel and the electrode.
Inventors: |
MATSUI; Kuniaki; (Osaka,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sharp Kabushiki Kaisha |
Osaka |
|
JP |
|
|
Family ID: |
57731069 |
Appl. No.: |
16/835580 |
Filed: |
March 31, 2020 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15205226 |
Jul 8, 2016 |
10642425 |
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16835580 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G06F 3/044 20130101;
G06F 2203/04105 20130101 |
International
Class: |
G06F 3/044 20060101
G06F003/044 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 10, 2015 |
JP |
2015-138806 |
Claims
1. An image display device comprising: a capacitive touch switch
that performs switching by detecting a finger based on a change in
capacitance that is caused when the finger comes close to a panel;
an image display panel configured to display an image; and a
capacitance detection sheet, wherein an image display region
corresponding to the capacitance detection sheet and an operation
region having the touch switch placed therein share a flat glass
plate as the panel; and the image display device is configured to
have a full-flat structure where the image display region and the
operation region are integrated.
2. The image display device according to claim 1, wherein the image
display region is provided with the capacitance detection sheet and
the image display panel in this order on a back surface of the
panel, and wherein the operation region is provided with a
conductive member, electrodes for detecting capacitance, and a
substrate in this order on the back surface of the panel.
3. The image display device according to claim 1, wherein the touch
switch is configured to perform at least one of an operation for
turning on or off power and an operation for displaying a menu
screen.
4. The image display device according to claim 2, wherein the touch
switch is configured to be provided with the conductive member
placed between the panel and the substrate.
5. The image display device according to claim 2, wherein the
plurality of electrodes are mounted on the substrate, and wherein
the plurality of electrodes are spaced out so as to have an air gap
formed between the one electrode and its adjacent electrode; and a
straight route connecting a touch position on the panel
corresponding to the one electrode to a center of the adjacent
electrode passes through the air gap.
6. The image display device according to claim 2, wherein a ground
pattern for preventing noise from outside to the electrodes is
provided on a surface of the substrate opposite a surface where the
electrodes are provided.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation under 35 USC .sctn. 120
of U.S. application Ser. No. 15/205,226, filed Jul. 8, 2016, which
claims priority to Japanese Application 2015-138806, filed Jul. 10,
2015, the entire disclosures of which are hereby incorporated
herein by reference.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The present invention relates to an image display device,
and more particularly, to a full-flat image display device provided
with a touch switch.
Description of the Related Art
[0003] In recent years, as image display devices, there are known
full-flat image display devices whose display screen and frame are
integrated. Compared to a conventional image display device whose
display screen and frame are separated, a full-flat image display
device is superior in design due to its sense of unity and the part
of the frame is not conspicuous thanks to the sense of unity, and
when the image display devices are arranged next to each other,
viewers get an impression that the image display devices are
smoothly connected. Therefore, a market demand for full-flat image
display devices is on the increase.
[0004] To realize a touch panel of a full-flat image display
device, a capacitive touch panel is desirable, which is operated
based on a change in capacitance that is caused when a fingertip or
the like comes close to known glass, by using a method of detecting
a touch on the glass (for example, see JP 2013-106308 A).
[0005] Furthermore, in recent years, there is a trend to increase a
size of a screen of an image display device, and a large screen is
also demanded for a full-flat image display device. In the case of
a large-screen image display device, in order to secure a strength,
glass on the whole surface of a display screen is possibly made
very thick, and for example, in the case of an 80-inch display, a
thickness of 3 mm or more is required.
[0006] Accordingly, to provide a mechanical operation button to a
frame part of a large-screen full-flat image display device, a hole
needs to be made to thick, large glass, and there are problems that
processing is not easy and the cost is high.
[0007] It is conceivable to provide a capacitive touch switch to
the frame, instead of a mechanical operation button, but in this
case, an area of a capacitance detection sheet for detecting a
change in capacitance has to be spread to the frame part.
[0008] However, normally, a capacitance detection sheet is made
according to a size of a display screen, and cannot be used for a
power switch or the like positioned at the frame part outside the
display screen. Also, in the case of using a capacitance detection
sheet which is larger than the display screen, the frame part
spreads also to parts other than a part where a power switch or the
like is disposed, and thus the design is impaired, and a problem is
caused at a time when a multi-screen is structured by combining a
plurality of image display devices next to one another. Also, there
is a problem that ordering a capacitance detection sheet which is
not in accordance with a size of a display screen increases burden
of cost.
[0009] It is also conceivable to configure a touch panel and a
touch switch by connecting a plurality of small-area capacitance
detection sheets, but in this case, components other than the
small-area capacitance detection sheets, such as cable wires for
connecting the capacitance detection sheets, become necessary, and
there are problems that burden of cost is increased, and also, that
assembly efficiency is deteriorated.
SUMMARY OF THE INVENTION
[0010] The present invention has been made in view of the above,
and has its aim to provide an inexpensive and easily assembled
full-flat image display device including a capacitive touch
switch.
[0011] An image display device including a capacitive touch switch
that performs switching by detecting a finger based on a change in
capacitance that is caused when the finger comes close to a panel,
where the touch switch includes the panel, a substrate on which an
electrode for detecting capacitance is mounted, and a conductive
member corresponding to the electrode, and where the conductive
member is fixed by being interposed between the panel and the
electrode.
[0012] According to the present invention, an inexpensive and
easily assembled full-flat image display device including a
capacitive touch switch may be realized. Also, even if components
for an electrode are not separately provided, it is enough if an
electrode is formed on a substrate on which a control circuit is
mounted, while using a conductive member which is thicker than the
component mounted on the substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a block diagram showing a schematic configuration
of the image display device of the present invention;
[0014] FIG. 2 is a front view of the image display device of the
present invention;
[0015] FIG. 3 is a left side view of a display unit and an
operation unit shown in FIG. 2;
[0016] FIG. 4 is an enlarged view of a part X of the operation unit
shown in FIG. 2;
[0017] FIG. 5 is a cross-sectional view of the operation unit shown
in FIG. 4, along a line A-A';
[0018] FIG. 6 is a flow chart showing a procedure performed by the
touch switch of the image display device of the present invention,
for detecting capacitance;
[0019] FIG. 7 is an explanatory diagram showing examples of a
detected value of capacitance at an electrode of a conventional
touch switch;
[0020] FIG. 8 is an explanatory diagram showing a mechanism which
causes erroneous operations due to coupling of capacitance with a
fingertrip in a capacitive touch panel using large glass;
[0021] FIG. 9 shows graphs showing examples of a detected value of
capacitance at the electrode of the touch switch of the present
invention;
[0022] FIG. 10 is an explanatory diagram showing a reason why
coupling of capacitance with an adjacent electrode of the touch
switch of the present invention is reduced;
[0023] FIG. 11 is a perspective view of the conductive member of
the touch switch according to the second embodiment;
[0024] FIG. 12 is an explanatory diagram showing an example of
installation of the conductive member shown in FIG. 11 on the touch
switch;
[0025] FIG. 13 is an explanatory diagram showing a structure of a
conventional touch switch;
[0026] FIG. 14 is an explanatory diagram showing a structure of the
touch switch according to the third embodiment;
[0027] FIG. 15 is an explanatory diagram showing problems caused by
providing the GND pattern inside the touch switch;
[0028] FIG. 16 is an explanatory diagrams showing a structure of
the touch switch according to the fourth embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0029] Hereinafter, the present invention will be described in
detail with reference to the drawings. Additionally, the
description below is only an example in every aspect, and should be
understood not to limit the present invention.
First Embodiment
[0030] <Configuration of Image Display Device 100>
[0031] In the following, a configuration of an image display device
100, provided with a touch switch 25, according to a first
embodiment of the present invention will be described with
reference to FIGS. 1 to 4.
[0032] FIG. 1 is a block diagram showing a schematic configuration
of the image display device 100 of the present invention. FIG. 2 is
a front view of the image display device 100 of the present
invention. FIG. 3 is a left side view of a display unit 101 and an
operation unit 102 shown in FIG. 2. FIG. 4 is an enlarged view of a
part X of the operation unit 102 shown in FIG. 2.
[0033] The image display device 100 is a device for displaying an
image/video, such as a moving image, a still image or a 3D image,
and includes a touch panel which is operated by touching a screen
with a fingertip or the like, and a touch switch for performing an
operation for turning on or off power or for displaying a menu
screen, based on a touch with a fingertip or the like on an
operation panel, for example.
[0034] As the image display device 100, there may be cited a
display of a television, a personal computer (PC), a public
display, a monitor, an electronic blackboard, or the like.
[0035] Furthermore, the image display device 100 is not limited to
a stationary image display device, and may be a portable image
display device such as a smartphone or a tablet terminal.
[0036] As shown in FIG. 1, the image display device 100 of the
present invention mainly includes a microcomputer 10, a signal
detection unit 11, a scaler 12, an image memory 13, an image
display unit 14, a non-volatile memory 15, a volatile memory 16, a
backlight 17, a power unit 18, a DC-DC converter 19, a timer 20, a
light receiving unit 21, a communication unit 22, an input terminal
unit 23, an indicator lamp 24, and a touch switch 25.
[0037] In the following, each structural element shown in FIG. 1
will be described.
[0038] The microcomputer 10 is a circuit mainly constituted of a
microprocessor, and is an arithmetic device that performs a process
of controlling various devices, and processing of an operating
system, application software and the like. Also, an ASIC
(Application Specific Integrated Circuit), which is an integrated
circuit designed and fabricated for a specific purpose, or a
circuit having other arithmetic functions may be included as a
peripheral circuit.
[0039] The signal detection unit 11 is a part for detecting input
signals input from external devices, not shown, through input
terminals 231 to 234.
[0040] Types of input signals include input signals for an analog
input terminal, such as a VGA terminal or a component terminal, for
a digital input device such as a DVI terminal, an HDMI (registered
trademark) terminal or a DisplayPort terminal, and for an input
terminal of a control system, such as an USB connector.
[0041] Furthermore, input signals wirelessly transmitted by
Bluetooth (registered trademark), a wireless LAN or the like may
also be detected without being limited to detection of input
signals transmitted by wire.
[0042] The scaler 12 is a part for processing image data. For
example, processes such as image correction, color correction,
.gamma. correction, double speed processing, OSD generation, and
OSD superimposition are performed.
[0043] The image memory 13 is a part for storing image data
processed by the scaler 12. For example, it is used for FRC (Frame
Rate Conversion).
[0044] The image display unit 14 is a part for displaying various
pieces of information, such as an input image and a setup screen
140.
[0045] Furthermore, a display surface of the image display unit 14
is covered by a touch panel, and a touch panel operation is allowed
by detecting a position of a fingertip or the like of a user
contacting the display surface. As a position detection method of
the touch panel, a capacitive method of detecting a change in the
capacitance caused by a finger coming close to the panel is
used.
[0046] Additionally, as the display panel of the image display unit
14, glass 26, which is shared with the touch switch 25, is used
(see FIG. 3).
[0047] The non-volatile memory 15 is a part for storing information
necessary to realize various functions of the image display device
100, such as static text of control programs, log information, user
setup information and system information. As the non-volatile
memory 15, a storage medium such as a flash memory or an EEPROM is
used.
[0048] The volatile memory 16 is a part for temporarily storing
various pieces of data and exchange results. The volatile memory 16
is used also as a work area for programs. As the volatile memory
16, a semiconductor device such as an SRAM, or a storage medium
such as a hard disk is used.
[0049] The backlight 17 is a part for illuminating liquid crystal
from a back surface of the image display unit 14. As a light source
of the backlight 17, an LED or a cold cathode fluorescent lamp
(CCFL) is used, for example. Moreover, a direct type, an edge light
type and other types may be used.
[0050] The power unit 18 is a part for converting external AC power
into DC power, and for supplying the power to each part of the
image display device 100. As the power unit 18, an AT power supply,
an ATX power supply, or an SFX power supply is used, for
example.
[0051] The DC-DC converter 19 is a part for reducing or boosting
the direct current input from the power unit 18, and for supplying
necessary power to each part of the image display device 100.
[0052] The timer 20 is a part for measuring elapsed times of
various processes by the image display device 100.
[0053] The light receiving unit 21 is a part for receiving an
infrared (IR) signal from a remote control, and accepts an
instruction from a user through reception of an infrared signal
from the remote control.
[0054] The communication unit 22 is a part for performing
communication with an external device in a wired or wireless manner
over a network, and for transmitting/receiving data. As the
network, a LAN, a wide area network (WAN) such as the Internet, a
dedicated communication line or the like is used.
[0055] As wireless communication standards, Bluetooth (registered
trademark), and IEEE802.11a, IEEE802.11b, IEEE802.11g and
IEEE802.11n, which are wireless LAN standards, may be cited, for
example.
[0056] As external devices as communication destinations, devices
that are capable of performing communication in a wired or wireless
manner, such as a PC, a mobile terminal, and a server, may be
cited, and also, an RS-232C, which is a legacy interface, and the
like are included.
[0057] The input terminal unit 23 is a part to which a terminal of
an external device is connected and a signal is input.
[0058] The input terminal unit 23 shown in FIG. 1 includes four
input terminals 231 to 234 which are capable of being connected to
a terminal of an external device, but this is only exemplary, and
any number of input terminals may be included.
[0059] Terminals that can be connected to the input terminal unit
23 include an analog input terminal, such as a VGA terminal or a
component terminal, a digital input device such as a DVI terminal,
an HDMI terminal or a DisplayPort terminal, and an input terminal
of a control system, such as an USB connector.
[0060] As the external devices, those capable of outputting signals
of a moving image or a still image, such as a PC, a mobile
terminal, a recorder, a video camera and the like, may be
cited.
[0061] The indicator lamp 24 is a lamp for displaying a power state
of the image display device 100 by an LED or the like. For example,
when the power of the image display device 100 is off, a red LED is
displayed, and when the power is on, a green LED is displayed.
[0062] The touch switch 25 is a part for accepting operations for
turning on or off power, displaying a menu screen, and the like,
with a capacitive touch switch.
[0063] The touch switch 25 accepts an operation when it is detected
by an electrode 30 that capacitance caused by a touch of a
fingertip or the like is at or above a predetermined threshold.
[0064] As shown in FIG. 2, the image display device 100 is mainly
divided into three parts, namely, the display unit 101, the
operation unit 102 and a support unit 103, and the touch switch 25
is provided to the operation unit 102.
[0065] In the following, the side of the image display device 100
seen from the front will be referred to as a front (or a front
part), and the side of a rear face will be referred to as a back
(or a back part).
[0066] As shown in FIG. 3, the display unit 101 and the operation
unit 102 share the glass 26 as a shared panel.
[0067] At the display unit 101, a capacitance detection sheet 141,
the image display unit 14, and a substrate 32 are provided in this
order on a back surface of the glass 26.
[0068] Furthermore, at the operation unit 102, a conductive member
29, the electrode 30, and a substrate 31 are provided in this order
on the back surface of the glass 26.
[0069] Additionally, the number of the substrate 31 is not limited
to one, and it is also possible to mount a plurality of
substrates.
[0070] As described above, although the glass 26 is shared, the
substrate 32 of the display unit 101 and the substrate 31 of the
operation unit 102 are independently provided, and thus
maintenance, such as replacement of the touch switch 25, is
facilitated.
[0071] As shown in FIG. 4, the operation unit 102 includes the
light receiving unit 21, the indicator lamp 24, and the touch
switch 25. A user performs an operation of turning on or off the
power or of displaying a menu screen, for example, by touching a
predetermined position on a glass surface of the touch switch 25
with a fingertip or the like.
[0072] A "substrate" of the present invention is realized by the
substrate 31. Also, a "panel" of the present invention is realized
by the glass 26.
[0073] <Configuration and Operation of Touch Switch 25>
[0074] Next, a configuration and operation of the touch switch 25
of the present invention will be described with reference to FIGS.
5 to 10.
[0075] FIG. 5 is a cross-sectional view of the operation unit 102
shown in FIG. 4, along a line A-A'. FIG. 6 is a flow chart showing
a procedure performed by the touch switch 25 of the image display
device 100 of the present invention, for detecting capacitance.
FIG. 7 is an explanatory diagram showing examples of a detected
value of capacitance at an electrode 30 of a conventional touch
switch 25. FIG. 8 is an explanatory diagram showing a mechanism
which causes erroneous operations due to coupling of capacitance
with a fingertrip in a capacitive touch panel using large glass.
FIG. 9 shows graphs showing examples of a detected value of
capacitance at the electrode 30 of the touch switch 25 of the
present invention. FIG. 10 is an explanatory diagram showing a
reason why coupling of capacitance with an adjacent electrode 30 of
the touch switch 25 of the present invention is reduced.
[0076] As shown in FIG. 5, the touch switch 25 of the present
invention is configured from an operation panel unit 251, an
electrode unit 252, and the substrate 31.
[0077] An AG (Anti-Glare, antireflection) film 27, the glass 26,
and ink 28 are provided to the operation panel unit 251 in this
order from the front side. The ink 28 is a black ink, for example,
and is applied to a back surface of the glass 26.
[0078] In this case, the AG film 27 has a thickness of 0.1 mm, the
glass 26 has a thickness of 3.2 mm, and the ink 28 has a thickness
of 20 .mu.m.
[0079] Furthermore, the substrate 31 is provided with electrodes
30A and 30B, and conductive members 29A and 29B are provided on the
electrodes 30A and 30B, respectively. A thickness, in a front-back
direction, of the conductive members 29A and 29B embedded in the
touch switch 25 is about 3 mm.
[0080] In FIG. 6, first, an activation process of the microcomputer
10 is performed, and when a change in capacitance is detected by
the electrode 30 in step S1 (step S1), the microcomputer 10
determines, in the following step S2, whether a detected value of
the capacitance is greater than a predetermined threshold or not
(step S2).
[0081] In the case where the detected value of the capacitance is
greater than the predetermined threshold (in the case where Yes is
determined in step S2), the microcomputer 10 performs a process
according to the detection result (step S3). Then, the
microcomputer 10 repeats the process in step S1 (step S1).
[0082] On the other hand, in the case where the detected value of
the capacitance is at or below the predetermined threshold (in the
case where No is determined in step S2), the microcomputer 10
repeats the process in step S1 (step S1).
[0083] In FIG. 7, (A) and (B) are each an example of a graph
showing a change over time in a detected value of capacitance
detected by the corresponding one of the two adjacent electrodes
30A and 30B of a conventional touch switch 25.
[0084] Here, horizontal axes in (A) and (B) in FIG. 7 indicate
time, and vertical axes indicate a size of a detected value of
capacitance detected by the electrode 30 (in arbitrary unit).
[0085] As shown in (A) and (B) in FIG. 7, according to the
conventional touch switch 25, when a finger of a user touches the
touch switch 25, a change in capacitance is only detected by the
corresponding electrode 30A, but a change in capacitance is
possibly also detected by the adjacent electrode 30B due to
coupling of capacitance with the fingertip. Such a tendency is
conspicuous especially in the case of thick, large glass, and may
result in an erroneous operation.
[0086] In a case where a capacitive switch is mounted by using
thick glass 26, when a user presses a glass surface of the touch
switch 25 with a finger, as shown in FIG. 8A, coupling of
capacitance may be caused not only with the electrode 30A under the
glass surface but also with the adjacent electrode 30B.
[0087] Also, as shown in FIG. 8B, in the thick glass 26, sensor
sensitivity may be reduced due to coupling of capacitance between
the adjacent electrodes 30A and 30B.
[0088] Accordingly, when the thick glass 26 is used for the touch
switch 25, erroneous operations not intended by a user often
occur.
[0089] Therefore, conventionally, to prevent such erroneous
operations due to coupling of capacitance with the adjacent
electrode 30B, and to correctly determine that the electrode 30A is
selected by a user, complex analysis of a change in capacitance is
often required, and there is a problem that power is consumed more
than necessary.
[0090] Results of measuring a change in capacitance by using the
touch switch 25 of the present invention are shown in FIG. 9.
[0091] In FIG. 9, (A) and (B) are each an example of a graph
showing a change over time in a detected value of capacitance
detected by the corresponding one of the two adjacent electrodes 30
of the touch switch 25 of the present invention.
[0092] Here in FIG. 9, a horizontal axis of (A) and (B) indicates
time, and a vertical axis indicates a size of a detected value of
capacitance (in arbitrary unit).
[0093] In FIG. 9, in a period 1, a user touched, with a finger, a
glass surface, of the touch switch 25, corresponding to only one of
the electrode 30A and the electrode 30B, and in a period 2, the
user touched, with a finger, a glass surface, of the touch switch
25, corresponding to both the electrode 30A and the electrode
30B.
[0094] As shown in (A) and (B) in FIG. 9, in the period 1, when the
finger of the user touched the glass surface, of the touch switch
25, corresponding to the electrode 30A, and a change in capacitance
was detected by the electrode 30A, a change in capacitance was not
detected by the adjacent electrode 30B.
[0095] Moreover, when the finger of the user touched the glass
surface, of the touch switch 25, corresponding to the electrode
30B, and a change in capacitance was detected by the electrode 30B,
a change in capacitance was not detected by the adjacent electrode
30A.
[0096] Furthermore, in the period 2, when the finger of the user
touched the glass surface, of the touch switch 25, corresponding to
both the electrode 30A and the electrode 30B, a change in
capacitance was detected by both the electrode 30A and the
electrode 30B.
[0097] A reason of such an improvement is considered to be as
follows; as shown in FIG. 10, because a straight route RT1
connecting the finger touching the glass surface, of the touch
switch 25, corresponding to the electrode 30A and the adjacent
electrode 30B is interrupted by an air gap between the two
electrodes 30A and 30B, the finger and the electrode 30B have to be
coupled through a longer route RT2, causing coupling strength of
capacitance to be reduced.
[0098] Also, unlike in a case of direct coupling of the planar
electrodes 30A and 30B, the conductive members 29A and 29B are
three-dimensionally structured with a thickness in the front-back
direction. Considering that relative permittivity of air is about
1.00058 and relative permittivity of glass is about 3.5 to 9.9,
contribution of capacitance from a side surface of the conductive
member 29B cannot be completely ignored, and a possibility of
contribution of direct coupling of capacitance between the finger
and an upper surface of the conductive member 29B being reduced by
the amount of contribution mentioned above is also conceivable as
one factor.
Second Embodiment
[0099] Next, a touch switch 25 of an image display device 100
according to a second embodiment of the present invention will be
described with reference to FIGS. 11, 12A and 12B.
[0100] FIG. 11 is a perspective view of the conductive member 29 of
the touch switch 25 according to the second embodiment. FIGS. 12A
and 12B are explanatory diagrams showing an example of installation
of the conductive member 29 shown in FIG. 11 on the touch switch
25.
[0101] As shown in FIG. 11, the conductive member 29 is formed from
an elastic member 291 on an inside, and a conductive sheet 292
provided to a peripheral surface of the elastic member 291.
[0102] As shown in FIG. 12A, when the conductive member 29 is
installed on the electrode 30, and then the operation panel unit
251 is pushed toward the substrate 31, the conductive member 29 is
deformed under a pressure from the substrate 31 and the operation
panel unit 251.
[0103] As shown in FIG. 12B, at this time, the conductive member 29
is contracted in a direction of an arrow DA, and also expanded in
directions of arrows RA and LA.
[0104] However, the conductive member 29 does not expand in a
direction of a surface where the conductive sheet 292 is not
wound.
[0105] This is because the conductive sheet 292 has no elasticity
or has only small elasticity, and elasticity of the elastic member
291 may be controlled by attaching such conductive sheet 292 on a
specific surface of the elastic member 291.
[0106] For example, in a case where the conductive sheet 292 is
wound around the elastic member 291 in a manner shown in FIG. 11,
the conductive member 29 is prevented from being deformed by
expanding in an x-direction. This is because a length Lx of the
conductive sheet 292 in the x-direction is maintained constant.
[0107] On the other hand, with respect to deformation of the
conductive member 29 in a y-direction, the conductive member 29 is
allowed to be deformed to expand in the y-direction under a
condition that a circumferential length 2Ly+2Lz of the conductive
sheet 292 stays constant.
[0108] As described above, the conductive member 29 which expands
only in a predetermined direction under pressure from the substrate
31 and the operation panel unit 251 may be realized.
Third Embodiment
[0109] Next, a touch switch 25 of an image display device 100
according to a third embodiment will be described with reference to
FIGS. 13 and 14.
[0110] FIG. 13 is an explanatory diagram showing a structure of a
conventional touch switch 25. FIG. 14 is an explanatory diagram
showing a structure of the touch switch 25 according to the third
embodiment.
[0111] In a case of providing the light receiving unit 21 and the
indicator lamp 24 to a conventional touch switch 25, because these
elements cannot be directly bonded to the glass 26, a two-part
structure, as shown in FIG. 13, including the substrate 31 for the
electrodes 30 and a control board 37 is adopted.
[0112] In FIG. 13, the substrate 31 including the electrodes 30A
and 30B is bonded to the glass 26 by an adhesive layer 33, and is
coupled with the control board 37 through a cable wire 34.
[0113] The control board 37 is provided with the light receiving
unit 21 and the indicator lamp 24 on a front surface facing the
glass 26, and is provided with a connector 35 and a control device
36 on a rear surface.
[0114] However, according to such a configuration, there are
problems that the cable wire 34 is susceptible to noise, and that a
cost is increased.
[0115] Accordingly, to solve such problems, the light receiving
unit 21 and the indicator lamp 24 are provided in a gap made by
conductive members 29 interposed between the glass 26 and the
substrate 31, as shown in FIG. 14.
[0116] This secures a space for disposing the light receiving unit
21 and the indicator lamp 24, and eliminates a need to provide the
unstable cable wire 34 between the substrate 31 and the control
board 37, and thus sensitivity of the touch switch 25 is extremely
enhanced.
Fourth Embodiment
[0117] Next, arrangement of a GND pattern 38 of a touch switch 25
of an image display device 100 according to a fourth embodiment of
the present invention will be described with reference to FIGS.
15A, 15B, 16A and 16B.
[0118] FIGS. 15A and 15B are explanatory diagrams showing problems
caused by providing the GND pattern 38 inside the touch switch 25.
FIGS. 16A and 16B are explanatory diagrams showing a structure of
the touch switch 25 according to the fourth embodiment.
[0119] As shown in FIG. 15A, the GND pattern 38 is sometimes
provided on the substrate 31 so as to prevent influence of noise
caused by coupling of capacitance with an adjacent electrode.
[0120] However, as shown in FIG. 15B, when the GND pattern 38 is
provided near the conductive member 29, if the conductive member 29
contacts the electrode 30 and the GND pattern 38 and is
short-circuited due to faulty installation of the conductive member
29 or the like, sensitivity of the touch switch 25 may be reduced
or normal operation is disabled.
[0121] Accordingly, to prevent such problems, the GND pattern 38 is
provided on a rear surface side of the substrate 31, as shown in
FIG. 16A. In terms of relationship of lines of electric force,
physical influence is small even if the GND pattern 38 is
positioned on the rear surface side of the substrate 31.
[0122] Also, by disposing the GND pattern 38 in this manner, even
if the conductive member 29 is horizontally shifted by an operation
error or the like, as shown in FIG. 16B, inconveniences due to
short-circuit caused by contact with the GND pattern 38 may be
avoided.
Other Embodiments
[0123] 1. In the first to the fourth embodiments, the conductive
member 29 is not limited to have a cuboid shape, and may have a
columnar shape, a semicircular column shape, or a shape combining
these shapes (fifth embodiment).
[0124] According to the above, an optimal conductive member 29
according to an area or a shape of the electrode 30 may be
provided.
2. In the first to the fifth embodiments, the conductive member 29
may be an elastic body of rubber, resin or the like, or the elastic
body itself may be conductive (sixth embodiment).
[0125] According to the above, an optimal conductive member 29
according to the structure of the touch switch 25 may be
provided.
[0126] As described above,
[0127] (i) an image display device of the present invention is an
image display device including a capacitive touch switch that
performs switching by detecting a finger based on a change in
capacitance that is caused when the finger comes close to a panel,
where the touch switch includes the panel, a substrate on which an
electrode for detecting capacitance is mounted, and a conductive
member corresponding to the electrode, and where the conductive
member is provided between the panel and the electrode, and is
fixed by being interposed between the panel and the electrode.
[0128] In the present invention, the "image display device" is a
device for displaying an image/video, such as a moving image, a
still image or a 3D image, and includes a touch panel which is
operated by touching a screen with a fingertip or the like, and a
touch switch for performing an operation for turning on or off
power or for displaying a menu screen, based on a touch with a
fingertip or the like on an operation panel, for example.
[0129] As the image display device, there may be cited a display of
a television, a personal computer (PC), a public display, a
monitor, an electronic blackboard, or the like.
[0130] Furthermore, the image display device is not limited to a
stationary image display device, and may be a portable image
display device such as a smartphone or a tablet terminal.
[0131] Furthermore, with respect to "when the finger comes close to
a panel", the finger is not restrictive, and a tip of a pen may
also be used, for example.
[0132] Moreover, preferred modes of the present invention will be
described.
[0133] (ii) The image display device according to the present
invention may further include a capacitance detection sheet, where
the panel has an area greater than the capacitance detection sheet,
and the touch switch is disposed on a region, of the panel, other
than a region of the capacitance detection sheet.
[0134] Accordingly, by configuring the touch switch by having a
part of the panel used as a panel for the touch switch, the part of
the panel may be effectively used, and also, because a capacitance
detection sheet is not required by the panel for the touch switch,
the cost may be greatly reduced. Also, assembly of the image
display device with the touch switch is facilitated.
[0135] (iii) According to the image display device of the present
invention, two or more of the electrodes may be mounted on the
substrate, and the touch switch comprises conductive members
corresponding to the electrodes, and each one of the conductive
members may be provided between the panel and the corresponding one
of the electrodes with a predetermined gap to another of the
conductive members.
[0136] Accordingly, because each one of the conductive members is
provided between the panel and the corresponding one of the
electrodes with a predetermined gap to another of the conductive
members, an image display device provided with a touch switch may
be realized according to which coupling strength of capacitance
between the electrodes is reduced and occurrence of an
unintentional erroneous operation which is caused by coupling of
capacitance inside the panel may be prevented by a simple and
inexpensive structure.
[0137] (iv) According to the image display device of the present
invention, the conductive member may be deformed in a predetermined
direction under pressure from the panel and the electrode, when
provided between the panel and the electrode.
[0138] Accordingly, by using the conductive member that is deformed
in a predetermined direction under pressure from the panel and the
electrode, unintended contact between the conductive member and
another electrode, element or the like due to deformation of the
conductive member may be prevented at the time of fitting the
conductive member between the panel and the substrate.
[0139] (v) According to the image display device of the present
invention, each one of the conductive members may be disposed on
the substrate along a direction in such a manner that another of
the conductive members is not positioned in a direction in which
the each one of the conductive members become deformed under
pressure from the panel and the corresponding one of the
electrodes.
[0140] Accordingly, by determining the direction of the conductive
member and disposing the conductive member, at the time of fitting
the conductive member between the panel and the electrode, such
that the other conductive member is not positioned in the direction
of deformation of the conductive member, the conductive member may
be prevented from being deformed and contacting the other
conductive member.
[0141] (vi) According to the image display device of the present
invention, the conductive member may be formed by having a
conductive sheet wound around a predetermined surface of an elastic
body having a cuboid, columnar or semicircular column shape, or a
shape combining the shapes, and the elastic body may include at
least one of urethane foam, rubber and resin, and be fixed between
the panel and the electrode under pressure from the panel and the
electrode.
[0142] Accordingly, the conductive member which is deformed in a
specific direction may be easily realized simply by having the
conductive sheet wound around the elastic body.
[0143] (vii) According to the image display device of the present
invention, a ground pattern for preventing noise from outside to
the electrode may be provided on a surface, of the substrate,
opposite a surface where the electrode is provided.
[0144] Accordingly, by providing the ground pattern on the
substrate, on the opposite side from the electrode, the conductive
member is prevented from being in contact with the ground pattern
for guarding and being short-circuited even if the conductive
member is disposed shifted from the electrode by an operation error
or the like.
[0145] (viii) According to the image display device of the present
invention, when the conductive member is provided between the panel
and the electrode, a gap of a predetermined size may be created
between the panel and the substrate, and an element may be provided
on the substrate with the gap.
[0146] Accordingly, by disposing an indicator LED and an IR light
receiving unit in the gap between the panel and the corresponding
substrate, a sensor board and a control board do not have to be
separated, and sensitivity is enhanced by eliminating unnecessary
cable wires, which are unstable, and also, because a sensor sheet
becomes unnecessary, costs for mold, mouse and the like may be
reduced.
[0147] The preferable aspects of the present invention include the
one formed by combining some of the above-mentioned plural
aspects.
[0148] Besides the above-mentioned embodiments, various
modifications for the present invention are possible. These
modifications should not be construed as not belonging to the scope
of the present invention. The accompanying claims and their
equivalents are intended to cover such forms or modifications as
would fall within the scope of the invention.
* * * * *