U.S. patent application number 13/075197 was filed with the patent office on 2011-11-17 for capacitive touch panel and a method of reducing the visibility of metal conductors in capacitive touch panel.
This patent application is currently assigned to TPK TOUCH SOLUTIONS (XIAMEN) INC.. Invention is credited to YUH-WEN LEE, Ching-Shan Lin.
Application Number | 20110279403 13/075197 |
Document ID | / |
Family ID | 44278666 |
Filed Date | 2011-11-17 |
United States Patent
Application |
20110279403 |
Kind Code |
A1 |
LEE; YUH-WEN ; et
al. |
November 17, 2011 |
CAPACITIVE TOUCH PANEL AND A METHOD OF REDUCING THE VISIBILITY OF
METAL CONDUCTORS IN CAPACITIVE TOUCH PANEL
Abstract
The present invention discloses a capacitive touch panel,
comprises a substantially transparent substrate and a transparent
sensing pattern. The transparent sensing pattern, which detects
touch signals, is formed on the substantially transparent
substrate. The transparent sensing pattern comprises a plurality of
conductor cells and at least one metal conductor disposed on the
substantially transparent substrate. The at least one metal
conductor connects two adjacent conductor cells. At least one
low-reflection layer is formed on the at least one metal conductor.
The low-reflection layer can reduce the reflected light therefore
reducing the visibility of the metal conductors.
Inventors: |
LEE; YUH-WEN; (Zhubei City,
TW) ; Lin; Ching-Shan; (Shanshang Township,
TW) |
Assignee: |
TPK TOUCH SOLUTIONS (XIAMEN)
INC.
|
Family ID: |
44278666 |
Appl. No.: |
13/075197 |
Filed: |
March 30, 2011 |
Current U.S.
Class: |
345/174 |
Current CPC
Class: |
G06F 3/0443 20190501;
G06F 3/0446 20190501; Y10T 29/49155 20150115; G06F 2203/04111
20130101 |
Class at
Publication: |
345/174 |
International
Class: |
G06F 3/045 20060101
G06F003/045 |
Foreign Application Data
Date |
Code |
Application Number |
May 16, 2010 |
CN |
201010176328.0 |
Claims
1. A capacitive touch panel, comprising: a substantially
transparent substrate; a transparent sensing pattern comprising at
least one metal conductor disposed on the substantially transparent
substrate; and at least one low-reflection layer formed on the at
least one metal conductor.
2. The capacitive touch panel according to claim 1, wherein the
transparent sensing pattern comprises at least two conductor cells
connected by the at least one metal conductor.
3. The capacitive touch panel according to claim 2, wherein the
transparent sensing pattern comprises a plurality of first
electrodes disposed in a first direction and a plurality of second
electrodes disposed in a second direction, and the first direction
is perpendicular to the second direction, and the first electrodes
and the second electrodes are insulated from each other, and at
least one electrode of the first electrodes or the second
electrodes comprises the at least two conductor cells.
4. The capacitive touch panel according to claim 3, wherein the
plurality of first electrodes and the plurality of second
electrodes are formed on the same layer and insulated by a
plurality of insulators with each insulator disposed between a
corresponding first electrode and a corresponding second
electrode.
5. The capacitive touch panel according to claim 3, wherein the
plurality of first electrodes and the plurality of second
electrodes are formed on the same surface of an insulating layer
with a plurality of through holes, and each second electrode is
divided into a plurality of sections by the plurality of first
electrodes with each section separately located between two
adjacent first electrodes, and a plurality of electrical conductors
are formed on the other surface of the insulating layer with two
ends of each electrical conductor respectively connected to two
adjacent sections of each second electrode via two corresponding
through holes.
6. The capacitive touch panel according to claim 5, wherein the
insulating layer is made of transparent insulation material.
7. The capacitive touch panel according to claim 2, wherein the at
least two conductor cells are made of substantially transparent
conductive material.
8. The capacitive touch panel according to claim 7, wherein said
transparent conductive material is selected from the group
consisting of Indium Tin Oxide (ITO) and antimony tin oxide
(ATO).
9. The capacitive touch panel according to claim 1, further
comprising a processing circuit for receiving and processing the
touch signals, and the transparent sensing pattern is connected to
the processing circuit via the at least one metal conductor.
10. The capacitive touch panel according to claim 9, wherein the
transparent sensing pattern comprises a plurality of first
electrodes disposed in a first direction and a plurality of second
electrodes disposed in a second direction, and the first direction
is perpendicular to the second direction, and the first electrodes
and the second electrodes are insulated from each other, and at
least one electrode of the first electrodes or the second
electrodes comprises the at least two conductor cells.
11. The capacitive touch panel according to claim 1, wherein the
reflectivity of the low-reflection layer is less than about
80%.
12. The capacitive touch panel according to claim 1, wherein the
low-reflection layer is made of material selected from the group
consisting of oxide material, nitride material and dark
UV-sensitive organic material.
13. The capacitive touch panel according to claim 12, wherein the
oxide material is selected from the group consisting of chromium
oxide, titanium oxide and zirconium oxide.
14. The capacitive touch panel according to claim 12, wherein the
nitride material is selected from the group consisting of chromium
nitride, titanium nitride and zirconium nitride.
15. The capacitive touch panel according to claim 12, wherein the
dark UV-sensitive organic material is selected from the group
consisting of brown, gray, and black photoresist.
16. The capacitive touch panel according to claim 1, further
comprising a passivation layer coated on the transparent sensing
pattern and the substantially transparent substrate.
17. A method of reducing the visibility of metal conductors in a
capacitive touch panel, comprising a step of forming a
low-reflection layer on at least one metal conductor.
18. The method according to claim 17, wherein the low-reflection
layer is made of a material selected from the group consisting of
oxide material and nitride material.
19. The method according to claim 18, wherein the oxide material is
selected from the group consisting of chromium oxide, titanium
oxide and zirconium oxide.
20. The method according to claim 18, wherein the nitride material
is selected from the group consisting of chromium nitride, titanium
nitride and zirconium nitride.
21. The method according to claim 17, wherein the low-reflection
layer is made of dark UV-sensitive organic material.
22. The method according to claim 21, wherein the dark UV-sensitive
organic material is selected from the group consisting of brown,
gray, and black photoresist.
23. The method according to claim 17, wherein the step of forming a
low-reflection layer on at least one metal conductor comprises the
following steps: coating a metal layer on a substantially
transparent substrate; coating a low-reflection layer on the metal
layer; and etching the metal layer and the low-reflection layer at
the same time by photolithography, resulting in the low-reflection
layer formed on the at least one metal conductor.
24. The method according to claim 17, wherein the step of forming a
low-reflection layer on at least one metal conductor comprises the
following steps: coating a metal layer on a substantially
transparent substrate; coating a low-reflection layer on the metal
layer; exposing the low-reflection layer by photolithography; and
etching the metal layer forming the at least one metal conductor by
using the low-reflection layer as etching mask resulting in the
low-reflection layer formed on the at least one metal
conductor.
25. The method according to claim 17, wherein the step of forming a
low-reflection layer on at least one metal conductor comprises the
following steps: coating a metal layer on a substantially
transparent substrate; etching the metal layer forming at least one
metal conductor; coating a low-reflection layer on the at least one
metal conductor; and exposing the low-reflection layer on the at
least one metal conductor by photolithography resulting in the
low-reflection layer formed on the at least one metal conductor.
Description
[0001] This application claims the benefit of People's Republic of
China Application No. 201010176328.0 filed on May 16, 2010.
FIELD OF THE INVENTION
[0002] The present invention relates to a capacitive touch panel
with a single layer of transparent conductive structure with low
visibility of metal conductors and a method of reducing the
visibility of metal conductors in capacitive touch panel.
BACKGROUND OF THE INVENTION
[0003] Nowadays, with the development of touch technology, touch
panels are widely used in many electronic products, such as cell
phones, personal digital assistants (PDAs), game input interfaces,
or computer touch screens. The touch panel is always integrated
with a display panel. It is convenient for a user to select an
option by touching a displayed image on the display panel to start
its corresponding operation.
[0004] According to different technology principles, there are many
types of touch panels, such as resistance touch panel, capacitive
touch panel, infrared sensing touch panel, electromagnetic sensing
touch panel, and acoustic wave sensing touch panel. Herein, the
capacitive touch panel is comparatively better because of its high
sensitivity, low cost, and simple structure. Theoretically, the
capacitive touch panel works by sensing capacitance of human
bodies. When a user touches the capacitive touch panel, partial
electric charges will be taken away to generate electrical current
signals, which are then sent to a controller. The controller will
compute the touch position by using the received signals.
[0005] Generally, a conventional capacitive touch panel comprises a
substantially transparent substrate, a transparent sensing pattern
on the substantially transparent substrate, and a passivation
layer. The transparent sensing pattern, for detecting touch
signals, comprises a plurality of electrodes disposed on the
substantially transparent substrate. The transparent sensing
pattern may be formed by coating, etching, or printing a
substantially transparent conductive layer which is made of a
substantially transparent conductive material, e.g. Indium Tin
Oxide (ITO) or antimony tin oxide (ATO). The transparent sensing
pattern may comprise a plurality of electrodes with a plurality of
conductor cells and electrical conductors connecting two of such
conductor cells. These conductor cells may be arranged in many
different ways, such as in two perpendicular directions of the
right angle coordinate system, in parallel directions, or in
radiant-type directions. Among these different ways, the way of
running in two directions has two types of arrangements of the
conductor cells and the electrical conductors. One is single layer
ITO structure and the other is double layer ITO structure. As to
the single layer ITO structure, the conductor cells in two
directions are disposed on the same layer. As to the double layer
ITO structure, the conductor cells are disposed on two different
layers.
[0006] A capacitive touch panel with single layer ITO structure
comprises a substantially transparent substrate, a transparent
sensing pattern, an insulating layer and a passivation layer. The
passivation layer is an outer layer disposed on the transparent
sensing pattern. The transparent sensing pattern comprises a
plurality of first electrodes and a plurality of second electrodes
respectively disposed on the same side of the substantially
transparent substrate in two different directions. The insulating
layer comprises a plurality of insulators located at corresponding
intersections of the first electrodes and the second electrodes to
provide insulation. The electrodes, both the first electrodes and
the second electrodes, are connected by electrical conductors at
the intersections.
[0007] In practice, due to the good conductivity and low cost,
metal materials (such as copper or aluminum) are often used to make
metal conductors as the electrical conductors in a capacitive touch
panel. However, because the metal conductors have a certain width,
users can always see the metal conductors in such a transparent
environment composed of substantially transparent substrate and
transparent sensing pattern. The visibility of metal conductors is
not desirable.
[0008] Therefore, in the past, two methods have been used to solve
the problem of visibility of metal conductors. The first one is to
reduce the size of metal conductors and limit the width within a
very small value, and the second one is to use transparent
conductive material (e.g. ITO) as electrical conductors to replace
the metal conductors. However, in practical production, the first
method is hard to achieve and cannot eliminate the problem of
visibility of metal conductors completely. As to the second method,
it is required to add another ITO photo-etching process (including
an ITO coating process, a photolithography exposure process and an
etching stripping process) and use a higher-cost material (ITO),
leading to an obvious increase in the manufacturing costs.
SUMMARY OF THE INVENTION
[0009] Therefore, an objective of the present invention is to
provide a capacitive touch panel with the low visibility of metal
conductors and good optical performance as reflection from the
metal conductors is reduced.
[0010] Another objective of the present invention is to provide a
method of reducing the visibility of metal conductors in capacitive
touch panel. The present invention can be practiced as a convenient
solution with high yield rate and low cost, and can help achieve
better optical performance.
[0011] A capacitive touch panel comprises a substantially
transparent substrate, and a transparent sensing pattern for
detecting touch signals. The transparent sensing pattern comprises
at least one metal conductor disposed on the substantially
transparent substrate; and at least one low-reflection layer formed
on at least one metal conductor.
[0012] A method of reducing the visibility of metal conductors in a
capacitive touch panel comprises the step of forming a
low-reflection layer on the metal conductors. The capacitive touch
panel comprises a substantially transparent substrate with a
transparent sensing pattern. The transparent sensing pattern
comprises at least one metal conductor disposed on the
substantially transparent substrate.
[0013] The present invention provides the method of coating a
low-reflection layer on each metal conductor to reduce the
reflected lights from metal conductors. In this way, there is no
need to reduce the width of the metal conductor. Also this makes it
easier to achieve high yield rate in the manufacturing process.
Furthermore, compared to the second method of adding another ITO
photo-etching process (including an ITO coating process, a
photolithography exposure process and an etching stripping
process), the present invention only adds a photolithography
exposure process in the original process. Thus, the manufacturing
process can be simplified, and the cost can be reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Skilled persons in the art will understand that the
drawings, described below, are for illustration purposes only and
do not limit the scope of the present invention in any way. In the
drawings, like reference numerals designate corresponding parts
throughout the several views.
[0015] FIG. 1 is a sectional view of first embodiment of the
present invention;
[0016] FIG. 2 is a cross-sectional view taken on the line B-B of
FIG. 1;
[0017] FIG. 3 is a partial plan view of first embodiment of the
present invention;
[0018] FIG. 4 is a partial plan view of the transparent sensing
pattern structure with a plurality of first conductor cells, second
conductor cells and first electrical conductors on the
substantially transparent substrate;
[0019] FIG. 5 is a partial plan view of the transparent sensing
pattern structure with the insulating layer on the first electrical
conductors;
[0020] FIG. 6 is a partial plan perspective view of second
embodiment of the present invention;
[0021] FIG. 7 is a sectional view of second embodiment of the
present invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0022] Referring to FIG. 1, FIG. 2 and FIG. 3, a capacitive touch
panel 10 in accordance with the first embodiment comprises a
substantially transparent substrate 1, a transparent sensing
pattern 2, an insulating layer 3, a passivation layer 4 and a
low-reflection layer 5. The transparent sensing pattern 2 detects
touch signals. It is formed on the substantially transparent
substrate 1. The transparent sensing pattern 2 comprises a
plurality of first electrodes 21 and second electrodes 22 arranged
in two directions respectively and disposed on the same side of the
substantially transparent substrate 1. Generally, the first
direction may be perpendicular to the second one. The insulating
layer 3 comprises a plurality of insulators 31. It is located at
corresponding intersections of the first electrodes 21 and the
second electrodes 22 to provide insulation. The passivation layer 4
is an outer layer disposed on the transparent sensing pattern
2.
[0023] Furthermore, each first electrode 21 comprises a plurality
of first conductor cells 211 and a plurality of first electrical
conductors 212, wherein each first electrical conductor 212
connects two adjacent first conductor cells 211. Each second
electrode 22 comprises a plurality of second conductor cells 221
and a plurality of second electrical conductors 222, wherein each
second electrical conductor 222 connects two adjacent second
conductor cells 221. The second electrical conductors 222 and the
first electrical conductors 212 are insulated via the insulators
31. In this embodiment, the second electrical conductors 222 are
metal conductors made of metal conductive materials, such as
silver, copper or aluminum. The low-reflection layer 5 comprises a
plurality of low-reflection strips 5a disposed on each second
electrical conductor 222, as shown in FIG. 1 and FIG. 2. The
reflectivity of the low-reflection layer 5 is less than about 80%.
The low-reflection layer 5 can reduce the reflected light therefore
reducing the visibility of the metal conductors. This embodiment
provides a capacitive touch panel with better optical
performance.
[0024] The low-reflection layer 5 can be made of oxide material,
nitride material, a mixture of oxide and nitride material, a dark
UV-sensitive organic material, etc. The oxide material may be metal
oxide, such as chromium oxide (CrO), titanium oxide (TiO) or
zirconium oxide (ZrO). The nitride material may be metal nitride,
such as chromium nitride (CrN), titanium nitride (TiN) or zirconium
nitride (ZrN). The dark UV-sensitive organic material may be brown,
gray, or black photoresist.
[0025] The first conductor cells 211, the second conductor cells
221 and the first electrical conductors 212 are made of a
substantially transparent conductive material, such as Indium Tin
Oxide (ITO) or antimony tin oxide (ATO). The insulating layer is
made of transparent insulation material, such as silica.
[0026] The capacitive touch panel further comprises a processing
circuit (not shown) for receiving and processing the touch signals
and a plurality of metal traces for carrying the touch signals to
the processing circuit. The metal traces are metal conductors and
comprise a plurality of first metal traces 23 and second metal
traces 24, as shown in FIG. 3. The first metal traces 23 connect
the first electrodes 21 to the processing circuit. The second metal
traces 24 connect the second electrodes 22 to the processing
circuit.
[0027] In this section, a manufacturing process of making the
capacitive touch panel in accordance with the first embodiment will
be depicted. The manufacturing method includes the following
steps.
[0028] Step 1, referring to FIG. 4, a sensing pattern 2 is formed
on the substantially transparent substrate 1. More specifically,
Step 1 further comprises: coating a transparent conductive material
layer on a substantially transparent substrate 1, and etching the
transparent conductive material layer to form a plurality of first
conductor cells 211 and a plurality of second conductor cells 221
respectively and a plurality of first electrical conductors 212.
Each first electrical conductor 212 connects two adjacent first
conductor cells 211.
[0029] Step 2, referring to FIG. 5, a plurality of insulators 31 is
formed on the sensing pattern 2. More specifically, this step
further comprises: coating a insulating layer 3 on the sensing
pattern 2 and etching the insulating layer 3 to form a plurality of
insulators 31 on the corresponding first electrical conductor
212.
[0030] Step 3, referring to FIG. 3, a plurality of second
electrical conductors 222 is formed on the insulators 31 as well as
the low-reflection strips 5a. The second electrical conductors 222
are metal conductors with good conductivity and connect between two
adjacent second conductor cells 221. There are three kinds of
methods to execute Step 3.
[0031] The first method comprises: coating a metal layer on the
substantially transparent substrate; coating a low-reflection layer
5 made of either metal nitride material or metal oxide material on
the metal layer by Physical Vapor Deposition (PVD) sputter coating;
and etching the low-reflection layer 5 and the metal layer at the
same time by photolithography to form metal conductors as the
second electrical conductors 222. After this step is finished, a
plurality of low-reflection strips 5a of the low-reflection layer 5
are formed on the metal conductors.
[0032] The second method comprises: coating a metal layer on the
substantially transparent substrate; coating a low-reflection layer
5 on the metal layer; exposing the low-reflection layer 5 by
photolithography to form a plurality of low-reflection strips 5a;
and etching the metal layer to form the metal conductors by using
the low-reflection strips 5a as etching mask. Thus, the
low-reflection strips 5a of the low-reflection layer 5 are disposed
on the metal conductors. The low-reflection layer 5 is made of dark
UV-sensitive organic material, such as black photoresist.
[0033] The third method comprises: coating a metal layer on the
substantially transparent substrate; etching the metal layer to
form the metal conductors as the second electrical conductors 222;
coating a low-reflection layer 5 on the metal conductors; and
exposing the low-reflection layer 5 by photolithography to form the
low-reflection strips 5a. After this step is finished, a plurality
of low-reflection strips 5a of the low-reflection layer 5 are
formed on the metal conductors. The low-reflection layer 5 is made
of dark UV-sensitive organic material, such as black
photoresist.
[0034] Step 4, a passivation layer 4 is coated on the transparent
sensing pattern 2.
[0035] As described above, the step 1 and step 3 of the
manufacturing process can be exchanged. And the quantity of the
first electrodes and the second electrodes can be increased or
decreased according to the resolution of capacitive touch
panel.
[0036] In the same way, a low-reflection layer 5 can be formed on
the first metal traces 23 and the second metal traces 24 to reduce
the visibility of the metal traces.
[0037] Referring to FIG. 6 and FIG. 7, a capacitive touch panel 10
in accordance with the second embodiment comprises a substantially
transparent substrate 1, a transparent sensing pattern 2, an
insulating layer 3, a passivation layer 4 and a low-reflection
layer 5. The transparent sensing pattern 2 is disposed on the
substantially transparent substrate 1. The transparent sensing
pattern 2 comprises a plurality of first electrodes 21 and a
plurality of second electrodes 22 respectively disposed on the same
layer in two directions. Each first electrode 21 comprises a
plurality of first conductor cells 211 and a plurality of first
electrical conductors 212 which connect two adjacent first
conductor cells 211 of the same electrode. Each second electrode 22
comprises a plurality of second conductor cells 221. The insulating
layer 3 comprises a plurality of through holes 32 and covers the
transparent sensing pattern 2. A plurality of second electrical
conductors 222 are disposed on the other surface of the insulating
layer 3 and connect two adjacent second conductor cells 221 via
through holes 32. In this embodiment, the second electrical
conductors 222 are also metal conductors made of metal conductive
materials, such as silver, copper or aluminum. The low-reflection
layer 5 comprises a plurality of low-reflection strips 5a disposed
on each second electrical conductor 222. The reflectivity of the
low-reflection layer 5 is less than about 80%. The low-reflection
layer 5 can reduce the reflected light therefore reducing the
visibility of the metal conductors. This embodiment provides a
capacitive touch panel with better optical performance.
[0038] The capacitive touch panel further comprises a processing
circuit (not shown) for receiving and processing the touch signals
and a plurality of metal traces for carrying the touch signals to
the processing circuit. The metal traces are metal conductors and
comprise a plurality of first metal traces 23 and a plurality of
second metal traces 24, as shown in FIG. 6. The first metal traces
23 connect the first electrodes 21 to the processing circuit. The
second metal traces 24 connect the second electrodes 22 to the
processing circuit.
[0039] The manufacturing process of the second embodiment is
similar to that of the first embodiment as described. The
difference between these two embodiments is the way of setting the
insulating layer.
[0040] Although certain embodiments of the present invention have
been fully described with reference to the accompanying drawings,
it is to be noted that various changes and modifications will
become apparent to those skilled in the art. Such changes and
modifications are to be understood as being included within the
scope of embodiments of this invention as defined by the appended
claims. It is to be understood that the present invention has been
described by way of illustration and not limitations.
* * * * *