1. Field of the Invention
The present invention generally relates to an electronic module, and more particularly, to a touch module.
2. Description of Related Art
Conventional push-button human machine interfaces cannot meet users' requirement any more with the development of multi-functional electronic devices. Accordingly, touch devices have been quickly developed. Compared to a conventional push-button operation interface, a touch device can be operated more conveniently and intuitionally. Through a touch device, a user can directly click at objects, menus, or icons displayed on a screen image by using a finger or stylus or operate these objects, menus, or icons with different gestures.
In more detail, a touch module includes an upper sensing electrode layer and a lower sensing electrode layer for respectively sensing touch inputs performed by the user along different directions. Besides, a touch module further includes an upper circuit layer and a lower circuit layer for respectively transmitting the sensing signals of the upper sensing electrode layer and the lower sensing electrode layer. Generally, the upper sensing electrode layer and the lower sensing electrode layer are disposed in a sensing area of the touch module, and the upper circuit layer and the lower circuit layer are disposed in a non-sensing area of the touch module. The non-sensing area surrounds the sensing area and is located at the border of a touch device. The upper circuit layer and the lower circuit layer in the non-sensing area are hidden by a blocking layer (for example, an ink layer) at the border of the touch device, so that the touch device could have an appealing appearance. Serious electrical interference will be caused if the upper circuit layer and the lower circuit layer overlap each other. Thus, in an existing touch device, the upper circuit layer and the lower circuit layer are usually not overlapped. However, such a design causes the total width of the upper circuit layer and the lower circuit layer to increase. As a result, the width of the non-sensing area and the blocking layer couldn't be reduced, which is against today's trend of narrow border design of touch devices.
A touch sensor is disclosed in China Patent Publication No. CN102707823A, in which a shielding sheet is disposed between conductive wires and the position where a user will directly contact, and the shielding sheet shields the conductive wires to prevent any unexpected capacitance variation between each conductive wire and the position touched by the user. A touch device is disclosed in China Patent Publication No. CN102681712A, in which a sensing layer is disposed at the periphery of the touch device for shielding any interference caused by a user's finger on the signal transmission lines in the peripheral area. A touch device is disclosed in China Patent No. CN202472596U, in which a shielding layer is disposed corresponding to peripheral connection lines, and an insulation pattern is formed between the shielding layer and the peripheral connection lines. A capacitive touch panel is disclosed in U.S. Patent No. US20110227859A1, in which an electromagnetic shielding layer is disposed on the bottom surface of a substrate.