U.S. patent application number 12/871771 was filed with the patent office on 2011-06-16 for electronic device.
This patent application is currently assigned to KABUSHIKI KAISHA TOSHIBA. Invention is credited to Shigeki NISHIYAMA.
Application Number | 20110141056 12/871771 |
Document ID | / |
Family ID | 43952806 |
Filed Date | 2011-06-16 |
United States Patent
Application |
20110141056 |
Kind Code |
A1 |
NISHIYAMA; Shigeki |
June 16, 2011 |
ELECTRONIC DEVICE
Abstract
According to one embodiment, an L-shaped printed circuit board
is connected to the periphery of a film sensor at a plurality of
connection portions. Long holes are each formed in the periphery of
a film sensor at the center of a portion of the film sensor located
between a corresponding pair of adjacent connection portions.
Inventors: |
NISHIYAMA; Shigeki;
(Hino-shi, JP) |
Assignee: |
KABUSHIKI KAISHA TOSHIBA
Tokyo
JP
|
Family ID: |
43952806 |
Appl. No.: |
12/871771 |
Filed: |
August 30, 2010 |
Current U.S.
Class: |
345/174 |
Current CPC
Class: |
G06F 3/04144 20190501;
G06F 3/04164 20190501 |
Class at
Publication: |
345/174 |
International
Class: |
G06F 3/041 20060101
G06F003/041 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 14, 2009 |
JP |
2009-283168 |
Claims
1. An electronic device comprising: a housing; a circuit board in
the housing, equipped with electronic components; and a film sensor
on the circuit board, connected to the circuit board at a plurality
of connection portions, the film sensor comprising a hole between
adjacent ones of the connection portions.
2. The electronic device of claim 1, wherein the hole is in a
center of a pair of the connection portions.
3. The electronic device of claim 1, wherein the hole comprises a
length greater than a width of the connection portions.
4. The electronic device of claim 1, wherein two or more holes are
between each pair of the connection portions.
5. The electronic device of claim 1, wherein the film sensor and
the circuit board are electrically connected to each other via a
conductive adhesive.
6. An electronic device comprising: a display exposed on a surface
of a housing; a film sensor built in the display; a slim circuit
board on a periphery of the film sensor, connected to the periphery
of the film sensor at a plurality of connection portions and
equipped with electronic components; and a long hole in the
periphery of the film sensor between a pair of adjacent ones of the
connection portions, extending in a direction intersecting a
direction of alignment of the connection portions.
7. The electronic device of claim 6, wherein the long hole is in a
center of the pair of the connection portions.
8. The electronic device of claim 6, wherein the long hole
comprises a length greater than a width of the connection
portions.
9. The electronic device of claim 6, wherein two or more long holes
are between each pair of the connection portions.
10. The electronic device of claim 6, wherein the touch film sensor
and the circuit board are electrically connected to each other via
a conductive adhesive.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2009-283168, filed
Dec. 14, 2009; the entire contents of which are incorporated herein
by reference.
FIELD
[0002] Embodiments described herein relate generally to an
electronic device with a touch panel, and more particularly, to an
electronic device, such as a personal digital assistant (PDA) or a
personal computer that is provided with a built-in touch sensor
formed of a film (hereinafter referred to as a "film sensor").
BACKGROUND
[0003] Jpn. Pat. Appln. KOKAI Publication No. 2008-234470 (Patent
Document 1) discloses a tough panel in which ends of the lines of a
pair of insulating-film side electrodes are connected to ends of
insulating-substrate side lines by a conductive adhesive. The touch
panel has a slit near a corner of the insulating film and near a
connecting portion that electrically connects ends of the
insulating-film side wiring and the insulating-substrate side
wiring.
[0004] The slit of the insulating film prevents stress
concentration in the above connection portions, when the touch
panel is heated to cause deformation of the insulating film and the
insulating substrate due to the difference in coefficient of
thermal expansion between the film and the substrate. Namely, the
slit functions to absorb deformation of the insulating film to
thereby prevent stress concentration in the connection portions. As
a result, detachment of the connection portions due to the stress
caused by thermal expansion is prevented.
[0005] However, since the insulating film expands in all planar
directions, stress occurs in, for example, connection portions
between the insulating film and another substrate and between the
above-mentioned lines. Namely, stress occurs in the two connection
portions serving as the insulating film connection portions,
whereby the above-mentioned detachment problem occurs. In
particular, in the case of a large touch panel, the deformation
amount of the insulating film relative to the substrate increases,
which means that the problem of detachment between the insulating
film and the substrate inevitably becomes conspicuous.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] A general architecture that implements the various feature
of the embodiments will now be described with reference to the
drawings. The drawings and the associated descriptions are provided
to illustrate the embodiments and not to limit the scope of the
invention.
[0007] FIG. 1 is a view illustrating an outward appearance of a PDA
as an example of en electronic device according to an embodiment of
the invention;
[0008] FIG. 2 is a block diagram illustrating the configuration of
the PDA of FIG. 1;
[0009] FIG. 3 is a block diagram illustrating the display control
application shown in FIG. 2;
[0010] FIG. 4 is an exploded perspective view illustrating a film
sensor assembly incorporated in the display of the PDA;
[0011] FIG. 5 is a schematic view illustrating a film sensor
incorporated in the film sensor assembly of FIG. 4;
[0012] FIG. 6 is a printed circuit board incorporated in the film
sensor assembly of FIG. 4;
[0013] FIG. 7 is a schematic view illustrating a structure seen
from the reverse side, the structure being obtained by attaching
the printed circuit board of FIG. 6 to the peripheral portion of
the film sensor of FIG. 5;
[0014] FIG. 8 is a sectional view taken along line VIII-VIII of
FIG. 7;
[0015] FIG. 9 is an enlarged view illustrating part of a first
modification of the embodiment, in which long holes are formed in
the peripheral portion of the film sensor of FIG. 5; and
[0016] FIG. 10 is an enlarged view illustrating part of a second
modification of the embodiment, in which a notch is formed, instead
of the long holes, in the peripheral portion of the film sensor of
FIG. 5.
DETAILED DESCRIPTION
[0017] Various embodiments will be described hereinafter with
reference to the accompanying drawings.
[0018] In general, according to one embodiment, a printed circuit
board 4 is attached to the film sensor 2 at a plurality of
attachment portions 3. Holes 2a are formed in the film sensor 2
between adjacent ones of the attachment portions 3.
[0019] FIG. 1 shows an outward appearance of a personal digital
assistant (PDA) 10 as one example of an electronic device according
to the embodiment.
[0020] As shown in FIG. 1, the PDA 10 includes a display 15 that
contains a touch sensor (film sensor) in the form of a film. The
display 15 provides various operation screens to a user, and
functions as a user interface for enabling the user to select an
item displayed on a selected screen by touching the item by, for
example, a finger 12 or using a touch pen (not shown). The film
sensor provided on the surface of the display 15 will be described
later.
[0021] FIG. 2 is a block diagram illustrating the configuration of
the PDA 10.
[0022] As shown in FIG. 2, the PDA 10 comprises a CPU 14 for
controlling the devices incorporated in the PDA 10, a display 15
with a film sensor described later, a memory 16, such as a flash
memory, for temporarily storing data, a communication unit 17
functioning as a connection interface to be connected to, for
example, the Internet, and a recording medium 18, such as an HDD or
a flash memory, which has a greater memory capacity than the memory
16.
[0023] The CPU 14 loads, in the memory 16, various applications,
such as an operating system (OS) and a display control application
100 stored in the recording medium 18, thereby controlling the
whole operation of the PDA 10 in accordance with commands supplied
via the film sensor of the display 15.
[0024] As shown in FIG. 3, the display control application 100
comprises a detection control unit 101, a display selection unit
102, an execution unit 103 and a storing unit 104. The detection
control unit 101 is connected to the film sensor described later,
and detects whether a finger 12 of the user or a touch pen touches
an item displayed on the screen of the display 15. When text data
is selected on the display 15, the display selection unit 102, for
example, highlights the selected text data. The execution unit 103
copies, detects, pastes, cuts or searches for the selected text
data. When the execution unit 103 searches for the selected text
data, it searches a built-in dictionary or searches the Internet
via the communication unit 17. The storing unit 104 stores a
display menu and/or item data (an item "copy," an item "delete," an
item "paste," an item "cut," an item "search," etc.).
[0025] FIG. 4 is an exploded perspective view illustrating a sensor
assembly 20 incorporated in the display 15. The sensor assembly 20
comprises a film sensor 2 provided on the surface of the display
15, a printed circuit board 4 attached to the reverse side of the
film sensor 2, a spacer 6 and a fixing frame 8.
[0026] The film sensor 2 has a structure in which XY patterns (not
shown) in a matrix are formed on a rectangular vinyl film, and the
ends of the patterns are lead to the edges of the film. A piezo
film sensor, for example, is known as the film sensor 2. The film
sensor 2 is formed of, for example, a polyethylene-based film
material.
[0027] The printed circuit board 4 is L-shaped and provided along a
pair of short and long sides of the film sensor 2. The circuit
board 4 has a circuit pattern (not shown) on a surface thereof that
faces the XY patterns of the film sensor 2, and has an IC chip (not
shown) mounted on the other surface. The printed circuit board 4 is
formed of glass epoxy.
[0028] When attaching the printed circuit board 4 to the film
sensor 2, the former is adhered to the sides of the latter so that
the circuit pattern of the former is connected to the XY patterns
of the latter via a conductive adhesive. As a result, the IC chip
on the printed circuit board 4 is electrically connected to the XY
patterns.
[0029] The spacer 6 is also L-shaped, and is provided along the
other sides of the film sensor 2. The fixing frame 8 is formed
rectangular to cover the reverse sides of the printed circuit board
4 and the spacer 6.
[0030] Namely, the sensor assembly 20 has a structure in which the
fixing frame 8 is adhered to the reverse surface of the periphery
of the film sensor 2, with the printed circuit board 4 and the
spacer 6 interposed therebetween.
[0031] The spacer 6 is provided to eliminate the step that is
formed between the film sensor 2 and the printed circuit board 4
when these two elements are adhered to each other.
[0032] As shown in FIG. 1, the PDA 10 constructed as above contains
all devices in its rectangular housing. Therefore, when the PDA 10
is turned on, the temperature in the housing increases with time.
In particular, the backlight of the liquid crystal display (LCD),
for example, is considered a main heat source.
[0033] When the PDA 10 is heated, the film sensor 2 and the printed
circuit board 4 of the sensor assembly 20 are also heated, whereby
they are thermally expanded to their respective degrees
corresponding to their respective thermal expansion coefficients.
Since the film sensor 2 and the printed circuit board 4 are
electrically connected at several connection portions via the
conductive adhesive as mentioned above, stress will concentrate on
the connection portions due to the difference between the thermal
expansion coefficients, whereby the connected portions may well be
detached.
[0034] More specifically, as shown in FIG. 6, the L-shaped printed
circuit board 4 of the embodiment is electrically connected to the
film sensor 2 at a plurality of connection portions via a
conductive adhesive 3. The connection portions will now be denoted
by reference number 3. The connection portions 3 are predetermined
in accordance with the circuit pattern of the printed circuit board
4.
[0035] The film sensor 2 of the embodiment is formed of a vinyl
film, and the printed circuit board 4 of the embodiment is formed
of glass epoxy. Thus, the film sensor 2 and the printed circuit
board 4 connected to each other at the connection portions 3 are
formed of materials having different coefficients of thermal
expansion.
[0036] Accordingly when the two members are simultaneously heated
to a certain temperature, a different may occur in the amount of
deformation between the members due to the different coefficients
of thermal expansion. In the combination of the materials employed
in the embodiment (i.e., the combination of vinyl and glass epoxy),
when they are heated under the same conditions, the film sensor is
thermally expanded by a greater ratio than the printed circuit
board 4.
[0037] Namely, in this case, the film sensor 2 is thermally
expanded more greatly than the printed circuit board 4 between
adjacent ones of the connection portions 3 arranged along the
printed circuit board 4. Accordingly, stress concentrates in the
connection portions 3. When the on and off operations of the PDA 10
are repeated to thereby repeat thermal expansion and contraction,
the above-mentioned stress concentration causes shearing force to
be exerted on the connection portions 3, with the result that the
connection portions 3 will be detached at worst.
[0038] To avoid this, a plurality of long holes 2a (see FIG. 5) for
leaking the above-mentioned stress are formed in the peripheral
portion of the film sensor 2. As shown in FIG. 7, the long holes 2a
are formed so that when the printed circuit board 4 is attached to
a peripheral portion of the film sensor 2, each of the long holes
is positioned at substantially the center of the corresponding
adjacent connection portions 3.
[0039] Further, the length of each long hole 2a (which is elongated
along the width of the printed circuit board 4) is designed to a
value that enables deformation of the film sensor 2 to be
sufficiently absorbed when a tensile force or a compression force
is exerted on the film sensor 2 between the corresponding adjacent
connection portions 3. More specifically, the long holes 2a are at
least set longer than the diameter of the connection portions
3.
[0040] The long holes 2a may have any arbitrary shape. However, it
is desirable that the periphery of each hole is curved so as not to
be sheared when the film sensor 2 is deformed as a result of stress
concentration.
[0041] Referring now to FIG. 8, a more detailed description will be
given of the function of the long holes 2a of the film sensor
2.
[0042] FIG. 8 is a sectional view illustrating a state in which the
L-shaped printed circuit board 4 of glass epoxy is connected to a
peripheral portion of the film sensor 2 of vinyl via the conductive
adhesive 3 at a plurality of connection portions.
[0043] When the sensor assembly 20 constructed as above is heated,
the film sensor 2 greater in coefficient of thermal expansion than
the printed circuit board 4 is more greatly expanded and deformed
than the printed circuit board 4. At this time, attention will now
be paid to the portions of the two members 2 and 4 located between
a certain pair of adjacent connection portions 3. A compression
force is exerted on the film sensor 2 between the certain pair of
adjacent connection portions 3 in the directions indicated by
arrows a.
[0044] When no long holes 2a are formed in the film sensor 2 unlike
the embodiment, the above-mentioned compression force causes stress
in the two connection portions 3. In contrast, the embodiment
employs a long hole 2a formed between the two connection portions
3. In this case, the long hole 2a is deformed to absorb the
compression force to narrow the width of the long hole 2a, whereby
no stress occurs in the two connection portions 3.
[0045] On the other hand, when the sensor assembly 20 is cooled
from this state, the film sensor 2 and the printed circuit board 4
both contract. Contraction of the film sensor 2 having a relatively
high coefficient of contraction can be compensated for if the long
holes 2a are widened, with the result that no stress occurs in the
two connection portions 3.
[0046] As described above, in the embodiment, since the
above-mentioned long holes 2a are formed in the peripheral portion
of the film sensor 2 adhered to the printed circuit board 4, stress
concentration in the connection portions 3 due to thermal expansion
can be prevented, thereby enabling the connection state of the film
sensor 2 and the printed circuit board 4 to be maintained in good
condition. In particular, in the embodiment, the connection state
of the film sensor 2 and the printed circuit board 4 can be
improved and the additional cost can be suppressed simply by
forming a plurality of long holes 2a in the peripheral portion of
the film sensor 2.
[0047] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the inventions. Indeed, the novel
embodiments described herein may be embodied in a variety of other
forms; furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the inventions. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
inventions.
[0048] FIG. 9 shows a first modification of the embodiment.
[0049] In this modification, two long holes 2a are formed between
each pair of adjacent connection portions 3 provided along the
peripheral portion of the film sensor 2. Thus, when the distance
between each pair of adjacent connection portions 3 is long, two or
more long holes may be formed between them.
[0050] FIG. 10 shows a second modification of the embodiment, in
which notches 2b are formed in place of the long holes 2a. Thus,
the means for avoiding stress concentration due to thermal
expansion are not limited to holes.
[0051] Further, although the above-described embodiments and
modifications employ one or more long holes 2a (or one or more
notches 2b) are formed between every pair of adjacent connection
portions 3, the invention is not limited to this. If the distance
between each pair of adjacent connection portions 3 is short, no
long holes 2a (no notches 2b) may be formed between them.
* * * * *