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Title:
PHOTOSENSOR AND DISPLAY UTILIZING THE SAME
Document Type and Number:
Japanese Patent JP2005203783
Kind Code:
A
Abstract:

To provide a photosensor which is resistant to noise, and stably outputs an output corresponding to an external light quantity.

The photosensor 40 comprises a sensor transistor Q1 to generate a photoelectric voltage corresponding to the light quantity when receiving external light, a selection transistor Q2 to selectively output a photoelectric voltage and a reference voltage, a current generating transistor Q3 to generate a sensor current corresponding to the output voltage of the transistor, and an output transistor Q4 to selectively output the sensor current. By a selection signal SELECT, the transistor Q4 is turned on and outputs an output current Iout in the state that the transistor Q2 is turned on and initialize a node n1 level to a reference voltage VDD, and the transistor Q4 is turned on and outputs an output current Iout in the state that the transistor Q2 is turned off. Since a photoelectric voltage relative to the reference voltage can be read out, a sensor voltage corresponding to an external light quantity can be output stably and resistantly to noise.


Inventors:
Min, Woong-kyu
Application Number:
JP2005000004906
Publication Date:
July 28, 2005
Filing Date:
January 12, 2005
Export Citation:
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Assignee:
SAMSUNG ELECTRONICS CO LTD
International Classes:
G02F1/13; G01J1/44; G02F1/133; G02F1/136; G09F9/00; G09G3/00; G09G3/34; H01J40/14; H01L27/146; H01L31/10; G09G3/36; (IPC1-7): H01L31/10; G02F1/13; G09F9/00
Domestic Patent References:
JPH05300432A1993-11-12
JPH04880A1992-01-06
JP2003333431A2003-11-21
JPH04332255A1992-11-19
JPS63161666A1988-07-05
JPH04183078A1992-06-30
JP2004343529A2004-12-02
JPH11307756A1999-11-05
JP2001004978A2001-01-12
JPH04254820A1992-09-10
JPS59116792A1984-07-05
Attorney, Agent or Firm:
社本 一夫
増井 忠弐
小林 泰
千葉 昭男
富田 博行
大塚 住江