FORCE-SENSING MODULES FOR LIGHT SENSITIVE SCREENS

• US 20120306821A1
• Filed: 08/20/2012
• Published: 12/06/2012
• Est. Priority Date: 12/23/2008
• Status: Active Grant

• Current Assignee: Chen-Chi Chu, Naejye Hwang
• Original Assignee: Chen-Chi Chu, Naejye Hwang
• Inventors: Chu, Chen-Chi, Hwang, Naejye
• Granted Patent: US 8,405,631 B2
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/042 by opto-electronic means

Abstract

A light sensitive screen includes at least one sensing element each being configured to detect a force applied to a position of the light sensitive screen and generate an electrical signal when a force is detected, and a sensor module configured to receive and process the electrical signal from the at least one sensing element. The sensor module may amplify the electrical signal from one of the at least one sensing element and generate an amplified signal, compare the amplified signal with a threshold and generate a comparing result, and generate a digital signal based on the comparing result, the digital signal including information as to whether the position of the light sensitive screen is touched.

Claims

1. A light sensitive screen comprising:

at least one sensing element each being configured to detect a force applied to a position of the light sensitive screen and generate an electrical signal when a force is detected; and

a sensor module configured to receive and process the electrical signal from the at least one sensing element, the sensor module comprising;

an amplifier configured to amplify the electrical signal from one of the at least one sensing element and generate an amplified signal;

a rectifier configured to convert the amplified signal into a direct-current (DC) signal including a first positive half and a second positive half;

a trigger configured to detect an edge each of the first positive half and the second positive half, and generate a first pulse signal and a second pulse signal for the first positive half and the second positive half, respectively; and

a digitizer configured to generate a digital signal based on the first pulse signal and the second pulse signal, the digital signal including information as to whether the position of the light sensitive screen is touched.

2. The light sensitive screen of claim 1, wherein each of the at least one sensing element includes one of a piezoelectric element or a piezoresistive element.

3. The light sensitive screen of claim 1, wherein the amplifier includes a pre-amplifier and a filter.

4. The light sensitive screen of claim 1, wherein the digital signal includes an active period from the occurrence of the first pulse signal to the occurrence of the second pulse signal.