# Patent

## Title
Single-layer projected capacitive touch panel and method of manufacturing the same

## Abstract

A single-layer projected capacitive touch panel has a glass cover, a touch sensing circuit layer, an insulating ink layer, a conductive wire layer, an insulator layer, a conductive glue layer and a flexible printed circuit (FPC) board. The touch sensing circuit layer, the insulating ink layer, the conductive wire layer, the insulator layer and the conductive glue layer are mounted on a circuit surface of the glass cover in sequence. The insulating ink layer covers the touch sensing circuit layer and has multiple through slots. Each through slot is filled with an electric conductor. The FPC is fastened on the conductive wire layer by a conductive glue laver.

## Background
BACKGROUND OF THE INVENTION
This application is a continuation Application of Ser. No. 14/177,226, filed Feb. 11, 2014, now U.S. Pat. No. 9,116,589, which is a continuation of application Ser. No. 12/661,787, filed Mar. 24, 2010, now U.S. Pat. No. 8,686,965, which claims priority to foreign Application No. TW099102092, filed Jan. 16, 2010, by the present inventors, which is incorporated herein by reference.


FIELD OF THE INVENTION
The present invention relates to a single-layer projected capacitive touch panel and a method for manufacturing the same, and more particularly to a single-layer projected capacitive touch panel in which a single glass layer is required, and a method of manufacturing the same.
DESCRIPTION OF THE RELATED ART
The advancement of touch panel technology has resulted in many consumer electronic products such as personal digital assistant (PDA), global positioning systems (GPS) and the like being equipped with touch panels.
Before iPhoneTM was released, resistive touch panels were generally used on small size portable electronic devices because they had sufficiently matured to keep costs low and be reliable. However, resistive touch panels cannot track more than one finger so resistive touch panels cannot resolve multipoint touches. After iPhoneTM was announced, projected capacitive touch panels became desirable because it enables multipoint touch.
With reference to FIG. 5, a conventional projected capacitive touch panel comprises a glass base (91), a touch sensing circuit layer (92), a conductive wire layer (93), an insulator layer (94), a conductive glue layer (95), a flexible printed circuit (FPC) board (96), an optical glue layer (97) and a glass cover (98). The glass base (91) has a circuit surface (911). The touch sensing circuit layer (92) is composed of single-layer touch sensing circuits, and the touch sensing circuit layer (92) and the conductive wire layer (93) are formed on the circuit surface (911) of the glass base (91) and are electronically connected together. The insulator layer (94) is formed on and covers the conductive wire layer (93), and the insulator layer (94) has a breach to partially expose the conductive wire layer (93). The conductive glue layer (95) is formed on the breach of the insulator layer (94) to cover the exposed conductive wire layer (93). The FPC board (96) is adhered to the conductive glue layer (95) and electronically to the conductive wire layer (93) via the conductive glue layer (95). The optical glue layer (97) is formed on the touch sensing circuit layer (92) and the insulator layer (94). The glass cover (98) has an operating surface (981) and an adhering surface (982). The adhering surface (982) of the glass cover (98) is adhered to the optical glue layer (97). The operating surface (981) of the glass cover (98) functions either as a touch surface or a protection cover to protect the touch sensing circuit layer (92), the conductive wire layer (93) and the conductive glue layer (95) on the glass base (91).
Since the conventional projected capacitive touch panel requires two glasses (91, 98), and the two glasses (91, 98) are fixed by the optical glue layer (97), the conventional projected capacitive touch panel has the disadvantages.
1. The optical glue layer (97) is positioned between the glass base (91) and the glass cover (98) so reduces penetrability of the conventional projected capacitive touch panel.
2. Adhering the two glasses (91, 98) requires great accuracy so affecting manufacturing yield rate. Current techniques cannot provide high accuracy of adhering the glasses for increased yield rate of manufacturing the conventional projected capacitive touch panel.
3. The insulator layer (94) and the FPC board (97) may be visible from the operating surface (981) of the glass cover (98) because the optical glue layer (97) is transparent. When installing the conventional projected capacitive touch panel on an electronic device, a casing on the electronic device must be designed to have opaque rims to cover the insulator layer (94) and the FPC board (97). However, such design limitation restricts application and in also requires accurate machining so further raising costs and reducing manufacturing yield.
To overcome the shortcomings, the present invention provides a single-layer projected capacitive touch panel and a method of manufacturing the same to mitigate or obviate the aforementioned problems.
SUMMARY OF THE INVENTION
The main objective of the invention is to provide a projected capacitive touch panel in which a single glass layer is required, and a method of manufacturing the same.
The projected touch panel in accordance with the embodiment of the present invention comprises a glass cover, a touch sensing circuit layer, an insulating ink layer, a conductive wire layer, an insulator layer, a conductive glue layer and a flexible printed circuit (FPC) board. The touch sensing circuit layer, the insulating ink layer, the conductive wire layer, the insulator layer and the conductive glue layer are mounted on a circuit surface of the glass cover in sequence. The insulating ink layer covers edges of the touch sensing circuit layer and has multiple through slots. Each through slot is filled with an electric conductor to electronically connect the conductive wire layer with the touch sensing circuit layer. The FPC is fastened on and electronically connects to the conductive wire layer by a conductive glue layer.
The method in accordance with the embodiment of the present invention comprises steps of:
providing a glass parent board divided into multiple glass covers, and each glass cover having an operating surface and a circuit surface;
forming touch sensing layers respectively on the glass covers, and each touch sensing layer partially formed on the circuit surface of each glass cover, having multiple edges and composed of single-layer touch sensing circuits;
forming insulating ink layers respectively on the touch sensing circuit layers, and each insulating ink layer formed on and near the edges of each touch sensing circuit layer to partially cover the touch sensing circuit layer, and each insulating ink layer having multiple through slots corresponding to and exposing the touch sensing circuit layer covered by the insulating ink layer;
forming electric conductors in the through slots;
forming conductive wire layers respectively on the insulating ink layers to contact with the electric conductors so the conductive wire layers electronically connect respectively to the touch sensing circuit layers via the electric conductors;
forming insulator layers respectively on the conductive wire layers, and each insulator layer having a breach to expose partial conductive wire layer;
separating the glass parent board into multiple glass covers;
installing a FPC board at the breach and on the exposed conductive wire layer on one separated glass cover with a conductive glue layer so the FPC board electronically connects to the conductive wire layer via the conductive glue layer.
Therefore, the touch panel of the embodiment of the present invention is thinner, provides better penetrability and higher yield rate and costs less than conventional projected capacitive touch panels.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.



BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A to 1H are a series of cross sectional side views showing manufacture of a single-laver projected capacitive touch panel in accordance with the present invention;
FIG. 2 is a representation of touch sensing circuit layers, insulating ink layers and conductive wire layers on a glass parent board;
FIG. 3 is a top view of a flexible printed circuit board mounted on a glass cover;
FIG. 4 is an explosive view of the single-laver projected capacitive touch panel in accordance with the present invention; and
FIG. 5 is a cross sectional view of a conventional projected capacitive touch panel.



DETAILED DESCRIPTION OF THE EMBODIMENTS
A method of manufacturing a single-layer projected capacitive touch panel in accordance with the present invention comprises steps of providing a glass parent board, forming touch sensing circuit layers, forming insulating ink layers having multiple through slots, forming electric conductors in the through slots, forming conductive wire layers, forming insulator layers, separating the glass parent board into multiple glass covers, installing a flexible printed circuit (FPC) board on one separated glass cover and applying a consolidating glue layer.
With reference to FIG. 1A, in the step of providing a glass parent board, the glass parent board is divided into multiple glass covers (10), and each glass cover (10) has an operating surface (11) and a circuit surface (12).
With reference to FIG. 1B, in the step of forming touch sensing layers, each touch sensing layer (20) is partially formed on the circuit surface (12) of each glass cover (10) of the glass parent board. With further reference to FIG. 2, each touch sensing layer (20) may be formed on a central zone of the circuit surface (12) of each glass cover (10) and has multiple edges. Further, the touch sensing circuit layer (20) is composed of single-layer touch sensing circuits, such as single-layer indium tin oxide (ITO) circuits.
With reference to FIG. 1C and FIG. 2, in the step of forming insulating ink layers having multiple through slots, each insulating ink layer (30) is formed on and near the edges of each touch sensing circuit layer (20) to partially cover the touch sensing circuit layer (20) so defining a touch zone (21) as uncovered areas of the touch sensing circuit layer (20). Further, each insulating ink layer (30) has multiple through slots (31) corresponding to and exposing the touch sensing circuit layer (20) covered by the insulating ink layer (30). In a preferred embodiment, the insulating layer (30) is composed of dark ink, and the insulating layer (30) and through slots (31) thereon are formed on the glass cover (10) to partially cover touch sensing circuit layer (20) by using screen-printing and curing technique. Consequently, other elements subsequently mounted on the insulating ink layer (30) are invisible when viewed from the operating surface (11) of the glass cover (10).
With reference to FIG. 1D, in the step of forming electric conductors in the through slots, the electric conductors (32) are filled respectively in the through slots (31). In a preferred embodiment, color of each electric conductor (32) is similar to the color of the insulating ink layer (30) to avoid people seeing the through slots (32) from the operating side (11) of the glass cover (10).
With reference to FIG. 1E, in the step of forming conductive wire layers, the conductive wire layers (40) are formed respectively on the insulating ink layers of the glass covers (10) on the glass parent board to contact with the electric conductors (32). Therefore, the conductive wire layers (40) electronically connect respectively to the touch sensing circuit layers (20) via the electric conductors (32). In a preferred embodiment, the conductive wire layers (40) are made of silver glue by using screen printing technique.
With reference to FIG. 1F, in the step of forming insulator layers, the insulator layers (50) are formed respectively on the conductive wire layers (40) by using screen printing technique to prevent the conductive wire layers (40) from oxidizing. Further, each insulator layer (50) has a breach (51) to expose partial conductive wire layer (40). In a preferred embodiment, the insulator layers (50) are made of transparent material.
In the step of separating the glass parent board into multiple glass covers, the glass parent board is separated into multiple glass covers (10) by a cutting machine.
With reference to FIG. 1G and FIG. 3, in the step of installing a FPC board on one separated glass cover, the FPC board (70) is attached to the breach (51) of the insulator layer (50) on the separated glass cover (10) with a conductive glue layer (60). The FPC board (70) is electronically connected to the conductive wire layer (40) exposed through the insulator layer (50) via the conductive glue layer (60). In a preferred embodiment, the conductive glue layer (60) is made of anisotropic conductive film (ACF) or anisotropic conductive paste (ACP), and the FPC board (70) is attached to the exposed conductive wire layer (40) with the conductive glue layer (60) by using a heat seal machine.
With reference to FIG. 1H, in the step of applying a consolidating glue layer, the consolidating glue layer (80) is applied to the FPC board (70) and the glass cover (10) to enhance fastening the FPC board (70) and prevent the FPC board (70) from coming off during other follow-up manufacturing procedures because of improper installation or dragging.
Therefore, with further reference to FIG. 4, a single-layer projected capacitive touch panel in accordance with the present invention manufactured by the above-mentioned method comprises a glass cover (10), a touch sensing circuit layer (20), an insulating ink layer (30), a conductive wire layer (40), an insulator layer (50), a conductive glue layer (60), a FPC board (70) and a consolidating glue layer (80).
The glass cover (10) has an operating surface (11) and a circuit surface (11). The operating surface (11) is for users to touch.
The touch sensing circuit layer (20) is mounted on the circuit surface (12) of the glass cover (10) and has multiple edges.
The insulating, ink layer (30) is formed on and covers the edges of the touch sensing circuit layer (20), and the uncovered touch sensing circuit layer (20) is defined as a touch zone (21). The insulating ink layer (30) further has multiple through slots (31). The through slots (31) correspond to and expose the touch sensing circuit layer (20) covered by the insulating ink layer (30), and each through slot (31) is filled with an electric conductor (32).
The conductive wire layer (40) is formed on and covers the insulating ink layer (30) so the conductive wire layer (40) electronically connects to the touch sensing circuit layer (30) via the electric conductors (32) in the through slots (31).
The insulator layer (50) is formed on and covers the conductive wire layer (40) and has a breach (51). The breach (51) exposes the partial conductive wire layer (40).
The conductive glue layer (60) is mounted on the breach (51) of the insulator layer (50) to cover the exposed conductive wire layer (40).
The FPC board (70) is attached to the conductive glue layer (60) to be mounted on the breach (51) of the insulator layer (50) and electronically connects to the conductive wire layer (40) via the conductive glue layer (60).
The consolidating glue layer (80) is applied to and between the FPC board (70) and the glass cover (10).
The projected capacitive touch panel in accordance with the embodiments of the present invention has advantages in the following.
1. Because the touch panel of the present invention only requires a single glass and the required optical glue layer in the conventional projected capacitive touch panel is unnecessary in the touch panel of the present invention, the touch panel of the embodiment of the present invention is indeed thinner than the conventional projected capacitive touch panel. Further, the touch panel of the embodiment of the present invention also provides better penetrability than the conventional projected capacitive touch panel.
2. The touch panel of the embodiment of the present invention does not need to adhere two glasses so the procedure of adhering glasses is not required and the cost for manufacturing the touch panel of the embodiment of the present invention is reduced. Further, manufacturing yield of the touch panel of the embodiment of the present invention is better than conventional projected capacitive touch panels. In addition, manufacturing costs of the touch of the embodiment of the present invention are also reduced because the touch panel of the embodiment of the present invention only requires a single glass.
3. Because the conductive wire layer (40), the insulator layer (50) and the conductive glue layer (60) are subsequently mounted on the insulating ink layer (30), they are hidden by the insulating ink layer (30) when viewed from the operating surface (11) of the glass cover (10). Therefore, it is convenient for designers to design a casing on an electronic device without rims to cover the conductive wire layer (40), the insulator layer (50) and the conductive glue layer (60) in the touch panel of the embodiment of the present invention.
Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only. Changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.

## Claims

1. A touch panel, comprising:
a glass cover having a touch sensing zone and at least one edge zone;
a touch sensing circuit layer formed on the glass cover, wherein the touch sensing circuit layer has a first portion located in the touch sensing zone and a second portion located in an edge zone of the at least one edge zone;
an insulating ink layer formed on the edge zone to cover the second portion of the touch sensing circuit layer, wherein the insulating ink layer has multiple through slots that correspond to and expose the second portion of the touch sensing circuit layer; and
a conduction path defined on the edge zone and formed on the insulating ink layer, wherein the conduction path electrically connects to the second portion of the touch sensing circuit layer via the multiple through slots.

2. The touch panel of claim 1, wherein the conduction path comprises a conductive wire layer formed on the insulating ink layer and a plurality of electric conductors connected to the conductive wire layer, wherein each electric conductor of the plurality of electric conductors is formed inside a corresponding through slot of the multiple through slots to connect to the second portion of the touch sensing circuit layer, and wherein the insulating ink layer is between the glass cover and the conductive wire layer.

3. The touch panel of claim 2, wherein the electric conductors and the insulating ink layer have a similar color.

4. The touch panel of claim 2, further comprising an insulator layer formed on the conductive wire layer, wherein the insulator layer has a breach portion to partially expose the conductive wire layer.

5. The touch panel of claim 2, further comprising an insulator layer, wherein the insulator layer has a breach portion, wherein the conductive wire layer comprises a plurality of conductive wires, and wherein a first end of each conductive wire of the plurality of conductive wires is exposed from the breach portion and a second end of each conductive wire of the plurality of conductive wires is connected to a corresponding electric conductor of the plurality of electric conductors.

6. The touch panel of claim 5, further comprising an auxiliary conduction path formed in the breach portion, wherein the auxiliary conduction path is connected to the first end of each conductive wire of the plurality of the conductive wires.

7. The touch panel of claim 6, wherein the auxiliary conduction path comprises a conductive glue layer.

8. The touch panel of claim 2, wherein the conductive wire layer is made of a silver glue.

9. The touch panel of claim 2, wherein the insulating ink layer comprises a first portion and a second portion, wherein the first portion of the insulating ink layer is between the glass cover and the conductive wire layer, and wherein the second portion of the insulating ink layer is between the conductive wire layer and the second portion of the touch sensing circuit layer, and the second portion of the insulating ink layer has the multiple through slots.

10. The touch panel of claim 1, wherein the insulating ink layer is made of a dark ink.

11. A touch panel, comprising:
a glass cover having a touch sensing zone and at least one edge zone;
a touch sensing circuit layer formed on the glass cover, wherein the touch sensing circuit layer has a first portion located in the touch sensing zone and a second portion located in an edge zone of the at least one edge zone;
an insulating ink layer formed on the edge zone to cover the second portion of the touch sensing circuit layer, wherein the insulating ink layer has a plurality of first hole portions that correspond to and expose the second portion of the touch sensing circuit layer;
an insulator layer formed on the edge zone, wherein the insulator layer has a second hole portion; and
a conduction path defined on the edge zone and formed on the insulating ink layer, wherein the conduction path extends from the plurality of first hole portions to the second hole portion so that the second portion of the touch sensing circuit layer electrically connects to a flexible printed circuit (FPC) board via the conduction path.

12. The touch panel of claim 11, wherein the conduction path comprises a conductive wire layer formed on the insulating ink layer, a plurality of electric conductors connected to the conductive wire layer and a conductive glue layer connected to the conductive wire layer, wherein each electric conductor of the plurality of electric conductors is formed inside a corresponding first hole portion of the plurality of first hole portions, wherein the conductive glue layer is formed in the second hole portion, and wherein the insulating ink layer is between the glass cover and the conductive wire layer.

13. The touch panel of claim 12, wherein the electric conductors and the insulating ink layer have a similar color.

14. The touch panel of claim 12, wherein the insulating ink layer is made of a dark ink, and wherein the conductive wire layer is made of a silver glue.

15. The touch panel of claim 12, wherein the second hole portion is a breach portion, wherein the conductive glue layer is located in the breach portion, wherein the conductive wire layer comprises a plurality of conductive wires, and wherein a first end of each conductive wire of the plurality of conductive wires is exposed from the breach portion and a second end of each conductive wire of the plurality of conductive wires is connected to a corresponding electric conductor of the plurality of electric conductors.

16. The touch panel of claim 15, wherein the flexible printed circuit (FPC) board is located on the breach portion to connect with the conductive glue layer.

17. The touch panel of claim 15, further comprising a consolidating glue layer formed between the flexible printed circuit (FPC) board and the glass cover.

18. The touch panel of claim 17, wherein the conductive glue layer, the conductive wire layer, and the insulating ink layer have a common plane, and wherein the consolidating glue layer is formed on the common plane.

19. The touch panel of claim 12, wherein the conductive glue layer is made of an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP).

20. The touch panel of claim 12, wherein the insulating ink layer comprises a first portion and a second portion, wherein the first portion of the insulating ink layer is between the glass cover and the conductive wire layer, and wherein the second portion of the insulating ink layer is between the conductive wire layer and the second portion of the touch sensing circuit layer, and the second portion of the insulating ink layer has the plurality of first hole portions.