Thin film transistor type optical sensor

• US 6,953,978 B2
• Filed: 06/16/2004
• Issued: 10/11/2005
• Est. Priority Date: 01/20/1999
• Status: Expired due to Term

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Kim, Jeong Hyun, Chang, Youn Gyoung, Kim, Se June
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): Lee, Eugene
• Application Number:
  US10/867,823
• Publication Number:
  US 20040222420A1
• Time in Patent Office: 482 Days
• Field of Search: 257/290, 257/291, 257/431, 257/432, 257/434, 257/444, 257/462, 257/307
• US Class Current: 257/432
• CPC Class Codes: G06V 40/1318 using electro-optical elements or layers, e.g. electroluminescent sensing
• CPC Class Codes: G06V 40/1382 Detecting the live character of the finger, i.e. distinguishing from a fake or cadaver finger
• CPC Class Codes: G06V 40/1394 using acquisition arrangements
• CPC Class Codes: H01L 31/1136 the device being a metal-insulator-semiconductor field-effect transistor

Abstract

A image detector comprises a light source for radiating light in accordance with a predetermined signal; a window for transmitting the light from the light source; a thin film phototransistor for generating an optical current in accordance with the intensity of external light; a storage capacitor for storing charge information transmitted from the thin film phototransistor; a thin film switching transistor for outputting the information stored in the storage capacitor in accordance with an external control signal; an insulating layer for covering the window, the thin film phototransistor, the storage capacitor, and the thin film switching transistor; a protecting layer formed on the insulating layer; and a conductive object detection pattern formed on the protecting layer to apply an electrical power supply signal to the light source when a conductive living object contacts the conductive objecting detecting pattern.

Claims

1. A thin film transistor type optical sensor, comprising:

a light source for radiating light in accordance with a predetermined signal;

a window for transmitting the light radiated by the light source;

a thin film phototransistor for generating an optical current in accordance with an intensity of received light;

a storage capacitor for storing charge information produced by the optical current generated by the thin film phototransistor;

a switching thin film transistor for outputting the information stored in the storage capacitor in accordance with an external control signal;

an insulating layer for covering the window, the thin film phototransistor, the storage capacitor, and the switching thin film transistor;

a protecting layer formed on the insulating layer; and

a living object detection pattern formed on the protecting layer for supplying an electrical power supply signal to the light source when a living object contracts the living object detection pattern.

2. The thin film transistor type optical sensor of claim 1 wherein the conductive object detection pattern is made of a material selected from the group consisting of indium tin oxide, tin oxide and TiOx.

3. The thin film transistor type optical sensor of claim 1 wherein the conductive object detection pattern comprises first and second electrodes spaced apart from each other at a predetermined distance.