Display integrated type position reading apparatus

A display integrated type position reading apparatus comprising:

• a display unit driven for display in accordance with a driving signal in synchronization with a predetermined clock signal;
• a transparent conductive sheet member mounted on a display screen of said display unit;
• depression detecting means for detecting that an arbitrary position on a main surface of said sheet member opposite to said display screen is depressed;
• position reading means, responsive to detection by said depression detecting means, for reading out an electric signal indicative of the depressed position with a cycle in synchronization with said predetermined clock signal;
• and
• display means for displaying an image on said display screen according to said depressed position read out by said position reading means,
• wherein said cycle is set so that position reading is carried out at a timing which avoids mixing of noise components, caused by a transition in the level of said driving signal, into said electric signal.

An integrated type display position reading apparatus comprising:

• display means for displaying images in accordance with driving signals applied in synchronization with a predetermined clock signal, said display means including a display screen with first and second transparent conductive sheets mounted thereon which are depressible;
• depression detecting means for detecting depression of said first and second transparent conductive sheets;
• and
• position reading means, responsive to detection of a depression of said first and second transparent conductive sheets, for determining a position of the detected depression in accordance with detected voltage output levels of said first and second transparent conductive sheets,
• said position determining means determining the position of the detected depression in synchronization with the predetermined clock signal to avoid mixing of noise into the detected voltage output levels due to transitions in the level of the driving signals.

A method of determining a depressed position on an integrated type display position reading apparatus which includes display means having a display screen with first and second transparent conductive sheets mounted thereon which are depressible, the display means being driven by a driving signal applied in synchronization with a predetermined clock signal, the method comprising the steps of:

• a) applying a first voltage to the first transparent conductive sheet;
• b) detecting a voltage output level of the first transparent conductive sheet subsequent application of the first voltage;
• c) applying a second voltage to the second transparent conductive sheet;
• d) detecting a voltage output level of the second transparent conductive sheet subsequent application of the second voltage;
• and
• e) determining the depressed position of the first and second transparent conductive sheets in accordance with the voltage output levels detected in said steps b) and d),
• said steps b) and d) of detecting occurring in synchronization with the predetermined clock signal to avoid mixing of noise into the detected voltage output levels due to transitions in the level of the driving signal.