METHOD FOR DRIVING INPUT CIRCUIT AND METHOD FOR DRIVING INPUT-OUTPUT DEVICE

• US 20110221704A1
• Filed: 03/08/2011
• Published: 09/15/2011
• Est. Priority Date: 03/12/2010
• Status: Abandoned Application

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Kurokawa, Yoshiyuki, Ikeda, Takayuki, Tamura, Hikaru, Ikeda, Masataka
• Application Number:
  US13/043,130
• Publication Number:
  US 20110221704A1
• Time in Patent Office: Days
• US Class Current: 345/175
• CPC Class Codes: G02F 1/13312 Circuits comprising photodetectors for purposes other than feedback
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

To reduce power consumption, included are a selection signal output circuit, a reset signal output circuit, and a photodetector circuit. The selection signal output circuit is for outputting a selection signal. The reset signal output circuit is for outputting a reset signal. The photodetector circuit is supplied with the reset signal and the selection signal, is brought into a reset state in accordance with the input reset signal, generates a voltage corresponding to the illuminance of incident light when light enters the photodetector circuit, and outputs the generated voltage as a data signal in accordance with the input selection signal. In a first period, the reset signal output circuit and the selection signal output circuit output the reset signal and the selection signal, respectively. In a second period, stopped are output of the reset signal from the reset signal output circuit and output of the selection signal from the selection signal output circuit.

Claims

1. A method for driving an input circuit including a selection signal output circuit outputting a selection signal;

a reset signal output circuit outputting a reset signal; and

a photodetector circuit supplied with the selection signal and the reset signal,

the method comprising;

outputting a data signal from the photodetector circuit when the reset signal output circuit and the selection signal output circuit output the reset signal and the selection signal, respectively, in a first period; and

stopping an output of the reset signal from the reset signal output circuit, and an output of the selection signal from the selection signal output circuit in a second period.

2. A method for driving an input circuit including a selection signal output circuit, a reset signal output circuit, and a photodetector circuit,

wherein the selection signal output circuit includes a first shift register to which a first start signal, a first clock signal, and a power supply voltage are input and outputs a selection signal when the first shift register outputs a signal,

wherein the reset signal output circuit includes a second shift register to which a second start signal, a second clock signal, and a power supply voltage are input and outputs a reset signal when the second shift register outputs a signal, and

wherein the photodetector circuit is supplied with the reset signal and the selection signal,

the method comprising:

outputting the second start signal and the second clock signal to the second shift register and outputting the first start signal and the first clock signal to the first shift register, in a first period; and

stopping an output of the second start signal and the second clock signal to the second shift register, and an output of the first start signal and the first clock signal to the first shift register, in a second period.

3. A method for driving an input circuit including a selection signal output circuit, a reset signal output circuit, and a photodetector circuit,

wherein the selection signal output circuit includes a first shift register to which a first start signal, a first clock signal, and a power supply voltage are input and outputs a selection signal when the first shift register outputs a signal,

wherein the reset signal output circuit includes a second shift register to which a second start signal, a second clock signal, and a power supply voltage are input and outputs a reset signal when the second shift register outputs a signal, and

wherein the photodetector circuit is supplied with the reset signal and the selection signal,

the method comprising:

outputting the second start signal, the second clock signal, and the power supply voltage to the second shift register and outputting the first start signal, the first clock signal, and the power supply voltage to the first shift register, in a first period; and

stopping an output of the second start signal, the second clock signal, and the power supply voltage to the second shift register, and an output of the first start signal, the first clock signal, and the power supply voltage to the first shift register, in a second period.

4. The method for driving an input circuit according to claim 3,

wherein an output of the first clock signal to the first shift register is stopped after stopping output of the power supply voltage to the first shift register, and

wherein an output of the second clock signal to the second shift register is stopped after stopping an output of the power supply voltage to the second shift register.

5. A method for driving an input-output device including a display circuit, a selection signal output circuit, a reset signal output circuit, and a photodetector circuit,

wherein the display circuit is supplied with a scan signal and supplied with an image signal in accordance with the scan signal to be in a display state depending on the image signal,

wherein the selection signal output circuit includes a first shift register to which a first start signal, a first clock signal, and a power supply voltage are input and outputs a selection signal when the first shift register outputs a signal,

wherein the reset signal output circuit includes a second shift register to which a second start signal, a second clock signal, and a power supply voltage are input and outputs a reset signal when the second shift register outputs a signal,

wherein the photodetector circuit is supplied with the reset signal and the selection signal, and performs a reading operation,

wherein, in the reading operation, the method comprises:

outputting the second start signal and the second clock signal to the second shift register and outputting the first start signal and the first clock signal to the first shift register, in a first period; and

stopping an output of the second start signal and the second clock signal to the second shift register, and an output of the first start signal and the first clock signal to the first shift register, in a second period.

6. A method for driving an input-output device including a display circuit, a selection signal output circuit, a reset signal output circuit, and a photodetector circuit,

wherein the display circuit is supplied with a scan signal and supplied with an image signal in accordance with the scan signal to be in a display state depending on the image signal,

wherein the selection signal output circuit includes a first shift register to which a first start signal, a first clock signal, and a power supply voltage are input and outputs a selection signal when the first shift register outputs a signal,

wherein the reset signal output circuit includes a second shift register to which a second start signal, a second clock signal, and a power supply voltage are input and outputs a reset signal when the second shift register outputs a signal,

wherein the photodetector circuit is supplied with the reset signal and the selection signal, and performs a reading operation,

wherein, in the reading operation, the method comprises:

outputting the second start signal, the second clock signal, and the power supply voltage to the second shift register and outputting the first start signal, the first clock signal, and the power supply voltage to the first shift register, in a first period; and

stopping an output of the second start signal, the second clock signal, and the power supply voltage to the second shift register, and an output of the first start signal, the first clock signal and the power supply voltage to the first shift register, in a second period.

7. The method for driving an input-output device according to claim 6,

wherein an output of the first clock signal to the first shift register is stopped after stopping an output of the power supply voltage to the first shift register, and

wherein an output of the second clock signal to the second shift register is stopped after stopping an output of the power supply voltage to the second shift register.