Citizen Electronics Co., Ltd.

Hidehiko Ide

Isao Miyashita

A key sheet module comprising a single-sided printed wiring board including a front surface on which a plurality of wiring patterns are provided and a plurality of holes provided at predetermined positions, rear-surface connection parts for the wiring patterns being exposed from the holes on a rear surface of the single-sided printed wiring board, an insulating layer provided on the front surface of the single-sided printed wiring board and having openings, patterns for switching of the wiring patterns and front-surface connection parts of the wiring patterns being exposed in the openings, the front-surface connection parts being connected by a front-surface jumper and the rear-surface connection parts being connected by a rear-surface jumper, respectively.

Key sheet module

A keysheet module is provided which comprises: a one-sided printed circuit board having a plurality of wiring patterns formed on one side thereof; and contact switches, LEDs for illuminating a keypad, and electric elements such as resistors and capacitors, all provided on the one-sided printed circuit board; wherein an insulating layer is provided between predetermined, separate wiring patterns of the plurality of wiring patterns and a conductive film jumper is formed over the insulating layer to three-dimensionally connect the separate wiring patterns. With this arrangement, a degree of freedom of locating LEDs and electric elements is enhanced, improving a keypad illumination efficiency. The use of the conductive film jumper can reduce a thickness of the keysheet module.

Keysheet module

The keysheet module has a flexible printed circuit board formed with dome-shaped depression switches on the upper surface thereof. Each of the depression switches comprises a first fixed contact, a second fixed contact surrounding the first fixed contact, a movable contact arranged over these fixed contacts to electrically connect and disconnect the first fixed contact and the second fixed contact, and a switch holding sheet arranged on the flexible printed circuit board to cover and hold the movable contact. An insulating film of an insulating paste is formed on the flexible printed circuit board in such a way that it has air holes formed therein to release air trapped in the movable contact. The switch holding sheet is arranged over the insulating film.

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Fujiyoshida, Japan

Hidehiko Ide