JP2003099192A - Capacitance type touch panel device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the thickness and cost of a touch panel device by using an electrode board for a display in common for a touch panel. SOLUTION: A common transparent electrode 9, liquid crystal 10, and a display transparent electrode 11 are successively laminated between two transparent insulating boards 7 and 8, and current detectors 1-4 for detecting currents running between a contact object such as the finger and the common transparent electrode 9 through the transparent insulating board 7 deposited at the common transparent electrode 9 side on which characters or picture are displayed, and with which the contact object is brought into contact are mounted on the four corners of the common transparent electrode 9 in order to detect the position coordinates of the contact part on a transparent insulating board 7, and the position coordinates of the contact part are calculated by a signal processing circuit 6 from current signals S1-S4 from the current detectors 1-4 at the four corners to be affected by the change of capacitance due to the contact of the contact object with the contact part on the transparent insulating board 7.

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a capacitance type touch panel device which is directly contacted by a contact object such as a finger, and more particularly to an electrostatic capacitance type touch panel device using a liquid crystal display mechanism. Capacitive touch panel device. 2. Description of the Related Art Conventionally, when a touch position such as a finger touches an input position on an image surface, a touch panel that outputs a current signal corresponding to the position, for example, a capacitance type touch panel (Japanese Patent Laid-Open No. -324203) is disclosed. In this capacitive touch panel, a second transparent substrate for preventing glare is attached to a touch surface side of a first transparent substrate provided with a transparent conductive film for detecting a touch position by a transparent adhesive. With this configuration, the transparent conductive film can be reliably prevented from being damaged, and the structure is simplified and the mechanical strength is improved. [0003] However, in such a structure of the capacitive touch panel, the touch panel itself must be used by being mounted on the front of the display, so that the thickness of the device itself increases. Or, there was a disadvantage that the cost was high. SUMMARY OF THE INVENTION The present invention has been made to solve such a conventional problem. By sharing an electrode plate of a display and a touch panel, it is possible to reduce the thickness and cost of the device itself. It is an object to provide a touch panel device. [0005] In order to achieve the above object, a capacitive touch panel device of the present invention comprises a common transparent electrode, a liquid crystal, and a display transparent electrode sequentially laminated between two transparent insulating plates to form a character. Capacitive touch panel device for displaying position and coordinates of a contact portion on a transparent insulating plate disposed on the side of a common transparent electrode with which a contact object such as a finger is displayed while displaying images and images, the four corners of the common transparent electrode A current detector that detects the current flowing between the contact object and the common transparent electrode via the transparent insulating plate, and measures the change in capacitance due to the contact object contacting the contact portion on the transparent insulating plate. A signal processing circuit is provided for calculating the position coordinates of the contact portion based on the current signals from the current detectors at the four corners affected. According to such a capacitive touch panel device, current detectors are attached to the four corners of a common transparent electrode functioning as one component of the display, and the position of the contact portion is determined by current signals from the current detectors at the four corners. By simply providing the signal processing circuit for calculating the coordinates, the display can have the function of the touch panel. Hereinafter, preferred embodiments of a capacitive touch panel device according to the present invention will be described with reference to the drawings. As shown in FIG. 1A, a capacitive touch panel device according to a preferred embodiment of the present invention
Between the two transparent insulating plates 7 and 8, from above, a common transparent electrode 9,
Liquid crystal screen 2 in which liquid crystal 10 and display transparent electrode 11 are sequentially laminated
0, and further includes a polarizing plate, an alignment film, a switching element for driving a liquid crystal, and the like (not shown), and a driving circuit (not shown) for driving liquid crystal through the switching element for driving a liquid crystal to display characters and images. It has. Further, as shown in FIG. 1B, current detectors 1 to 4 are attached to the four corners of the common transparent electrode 9 to constitute a current detection circuit 5 together with the common transparent electrode 9. Each of the current detectors 1 to 4 of the current detection circuit 5 is connected to a signal processing circuit 6, and the signal processing circuit 6 is connected to a control circuit 12 that controls the entire touch panel device. Next, a description will be given of the display and coordinate detection operation of the capacitive touch panel device configured as described above. First, a power supply is turned on, a switching circuit for driving a liquid crystal is driven by a driving circuit, and an arrangement state of the liquid crystal is changed to display characters and images on the liquid crystal screen 20. At this time, since the voltages are applied from the four corners of the common transparent electrode 9, the electric field spreads to the common transparent electrode 9 and an electric field of a uniform voltage is generated on the liquid crystal screen 20. In such a state, when a contact portion on the transparent insulating plate 7 where an item to be selected from characters or images displayed on the liquid crystal screen 20 is located with a contact object such as a finger, the contact portion becomes a capacitor. Since the capacitance changes due to the coupling, current signals S1 to S4, which are respectively proportional to the distance to the contact object, flow through the current detectors 1 to 4 attached to the four corners of the common transparent electrode 9. The signal processing circuit 6 calculates the position coordinates of the finger based on the current values detected by the current detectors 1 to 4, and outputs a coordinate signal S5 indicating the position coordinates to the control circuit 12. The control circuit 12 can specify a touch position on a character or an image displayed on the liquid crystal screen 20 based on the coordinate signal S5. Therefore, the control circuit 12 displays characters or images on the liquid crystal screen 20 or causes other devices to process the characters and images based on the content corresponding to the touched location. As described above, the function of the touch panel can be provided only by attaching the current detectors 1 to 4 to the four corners of the common transparent electrode 9 used in the liquid crystal screen 20 for displaying characters and images. That is, the electrodes of the liquid crystal display and the touch panel can be shared. As the liquid crystal screen 20 of such a capacitive touch panel device, a TFT liquid crystal in which a switching element for driving the liquid crystal is a TFT is suitable in terms of light weight and constant power consumption. Also, other liquid crystals can be used in the present invention. As is apparent from the above description, according to the capacitive touch panel device of the present invention, the electrodes of the touch panel and the display can be shared, and the display can have the function of the touch panel. Therefore, the thickness and cost of the touch panel device itself can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a preferred embodiment of a capacitive touch panel device of the present invention, wherein FIG.
(B) is a block diagram. [Description of Signs] 1, 2, 3, 4,..., Current detector 6,... Signal processing circuit 7, 8,..., Transparent insulating plate 9,. ..... liquid crystal screens S1, S2, S3, S4 ..... current signals

Claims (1)

1. A common transparent electrode (9), a liquid crystal (10), and a display transparent electrode (11) between two transparent insulating plates (7, 8).
In order to detect the position coordinates of the contact portion on the transparent insulating plate arranged on the side of the common transparent electrode to be contacted with a contact object such as a finger while displaying a character or an image, in a capacitive touch panel device At each of the four corners of the common transparent electrode, current detectors (1 to 4) for detecting a current flowing between the contact object and the common transparent electrode via the transparent insulating plate are attached. A signal for calculating position coordinates of the contact portion based on current signals (S1 to S4) from the current detectors at four corners affected by a change in capacitance due to contact with the contact portion on the transparent insulating plate. A capacitance type touch panel device comprising a processing circuit (6).