Thin film transistor type optical sensor

• US 6,774,396 B1
• Filed: 01/19/2000
• Issued: 08/10/2004
• 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): Jackson, Jerome
• Assistant Examiner(s): Lee, Eugene
• Application Number:
  US09/487,173
• Time in Patent Office: 1,665 Days
• Field of Search: 257/72, 257/291, 257/292, 257/431, 257/59, 250/208.1, 250/208.4, 382/124, 356/445, 324/76.79, 324/76.81
• US Class Current: 257/59
• 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. An image detector, comprising:

a conductive object detection pattern, wherein the conductive object detection pattern has a plurality of electrodes, the plurality of electrodes being alternately disposed;

a light source for illuminating an object on the conductive object detection pattern;

a sensor for sensing an image of the object;

a power source selectively supplying power to the light source; and

a controller detecting a current flowing through the conductive object detection pattern, and in response thereto supplying a control signal to the power source to selectively supply power to the light source.

2. The image detector of claim 1 wherein the plurality of electrodes includes spaced apart first and second electrodes.

3. The image detector of claim 2 wherein the controller transmits a first electrical signal to the first electrode and receives a second electrical signal from the second electrode and detects a conductivity between the first and second electrodes.

4. The image detector of claim 1 wherein the conductive object detection pattern is made of a material selected from a group consisting of indium tin oxide, tin oxide and TiOx.

5. The image detector of claim 1 wherein plurality of electrodes includes spaced apart first and second electrodes, each of the first and second electrodes having a finger-shaped pattern, fingers of the first and second electrodes being alternately disposed.

6. The image detector of claim 1 wherein plurality of electrodes includes spaced apart first and second electrodes, the first and second electrodes being in parallel and having a P-shaped pattern.

7. The image detector of claim 1 wherein the plurality of electrodes includes spaced apart first and second electrodes, the first electrode having a P-shaped pattern and the second electrode being disposed adjacent the first electrode.

8. The image detector of claim 1 wherein the plurality of electrodes includes a triangle-shaped pattern, a part of said triangle-shaped pattern being cut so as to form first and second electrodes.

9. The image detector of claim 1 wherein the plurality of electrodes includes spaced apart first and second electrodes, the first and second electrodes being disposed in parallel so as to form a rail-shaped pattern.

10. The image detector of claim 1 wherein the plurality of electrodes includes spaced apart first and second electrodes, the first electrode having a U-shaped pattern and the second electrode having an I-shaped pattern.

11. The image detector of claim 1 wherein the plurality of electrodes includes spaced apart first and second electrodes, the first and second each having a coil-shape pattern.

12. The image detector of claim 1 wherein plurality of electrodes includes spaced apart first and second electrodes, the first electrode having spiral-shaped pattern and the second electrode being disposed adjacent to the first electrode.

13. The image detector of claim 1 wherein the controller supplies the control signal to the power source to supply power to the light source in response to a living object residing on the conductive object detection pattern.

14. The image detector of claim 1, wherein the controller receives an electrical source for providing the current flowing through the conductive object detection pattern.

15. The image detector of claim 1, wherein the sensor is a thin film transistor optical sensor.

16. The image detector of claim 15, wherein the plurality of electrodes includes spaced apart first and second electrodes.

17. The image detector of claim 16, wherein the controller transmits a first electrical signal to the first electrode and receives a second electrical signal from the second electrode and detects a conductivity between the first and second electrodes.