Alps Electric Co., Ltd.

Brinks Hofer Gilson & Lione

Mikio Matsumoto

Shinichi Higuchi

Shinji Hirano

Yoshihisa Endo

Kinya Inoue

Kouichi Ogino

Tadashi Manome

A liquid crystal display device with a tablet reduced in apparatus thickness and enhanced in display visibility. The liquid crystal display device mainly composed of a liquid crystal display upper glass plate, a liquid crystal, and a liquid crystal display lower glass plate is connected with a tablet on the upper glass plate, the tablet being mainly composed of a film having a first transparent electrode. A second transparent electrode arranged on the upper glass plate is made function as both an electrostatic capacity detecting electrode and a display electrode. Namely, display is made by the second transparent electrode and a third transparent electrode and a coordinate on the tablet is detected by the first transparent electrode and the second transparent electrode.

Liquid crystal display device with tablet

A coordinate input apparatus which performs an input operation with high precision by use of either an operator's finger or an input pen. The input apparatus includes a tablet having a plurality of X electrodes and Y electrodes arranged in the form of a matrix on the respective top and bottom surfaces of a glass substrate. The input apparatus also has a first oscillation circuit connected to the X electrodes through an analog switch. It is further provided with an input pen containing a second oscillation circuit. When the pen is used to perform the input operation through use of coordinates, the following method of determining the coordinates designated by the pen is employed. A voltage oscillating from the pen is applied to each electrode through capacitance, and the resulting output voltage varies depending on the distance from each electrode to the pen. Based on the varied output voltages, a predetermined computation process is executed to determine the coordinates designated by the pen. On the other hand, when the operator's finger is used to perform the input operation, the analog switch is switched to the first oscillation circuit. Then, a voltage at a predetermined frequency is sequentially applied to each of the X electrodes from the first oscillation circuit, and the voltage applied across the X and Y electrodes is changed due to a decrease in the capacitance therebetween caused by the touching of the finger. Based on this change, coordinates designated by the finger is detected.

Coordinate input apparatus with pen and finger input detection

Growing community of inventors

Fukushima-ken, Japan

Mikio Matsumoto