Image sensing apparatus

• US 7,079,189 B2
• Filed: 08/08/2001
• Issued: 07/18/2006
• Est. Priority Date: 08/11/2000
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tsujii, Osamu, Tamura, Toshikazu
• Primary Examiner(s): Ho, Tuan
• Assistant Examiner(s): Villecco, John M.
• Application Number:
  US09/923,422
• Publication Number:
  US 20020044211A1
• Time in Patent Office: 1,805 Days
• Field of Search: 348/244, 348/250, 348/318, 348/230.1, 348/297, 348/312, 348/372, 250/208.4, 250/339.06, 250/348, 250/349, 250/354.1, 250/370.07, 250/370.08, 250/370.09, 250/393, 378/96, 378/97, 378/98, 378/101, 378/108, 378/109, 378/110, 378/111, 378/112
• US Class Current: 348/372
• CPC Class Codes: G01T 1/2928 using solid state detectors
• CPC Class Codes: H04N 25/63 applied to dark current
• CPC Class Codes: H04N 25/709 Circuitry for control of the power supply
• CPC Class Codes: H04N 5/32 Transforming X-rays cameras or camera modules for generating image signals from X-rays H04N23/30; circuitry of SSIS for transforming X-rays into image signals H04N25/30

Abstract

For providing a longer lifetime and sensing an image with less noise, there is provided an image sensing apparatus having a flat panel sensor for detecting radiations, a first power circuit for supplying an electric power to the flat panel sensor, a read-out circuit for reading out data of the flat panel sensor circuit, a second power circuit for supplying an electric power to the read-out circuit, and a control circuit for turning the first power circuit on by a first timing signal and for turning the second power circuit on by a second timing signal.

Claims

1. An image sensing apparatus comprising:

a radiation generating apparatus adapted to generate radiation;

a sensor comprising a plurality of image pick up elements for converting radiation to electrical signals;

a signal line adapted to read out said electrical signals from said image pick up elements;

a preamplifier adapted to amplify said electrical signals read out from said image pickup elements through said signal line;

a first power source adapted to set said signal line to a reference potential so as to set said image pick up elements to an initialized state;

a second power source adapted to supply electrical power to said preamplifier; and

a control circuit adapted to transmit an exposure permission signal to the radiation generating apparatus after initializing the plurality of image pick up elements, and control the first power source and the second power source to drive the preamplifier after transmission of the exposure permission signal,

wherein the control circuit stops the power supply from the second power source after reading out the electrical signals from the image pick up element.

2. An image sensing apparatus according to claim 1, wherein said control circuit controls said second power source so as to start supply of electrical power to said preamplifier on the basis of a timing of a reception of an exposure completion signal for said radiation generating apparatus.

3. An image sensing apparatus according to claim 2, wherein the exposure completion signal is generated by a radiation exposure dose monitor (AEC) in accordance with a reception of radiation or a monitor circuit for monitoring the electrical power of said radiation generating apparatus.

4. An image sensing apparatus according to claim 1, further comprising an exposure permission timer adapted to generate a radiation exposure permission signal for said radiation generating apparatus to generate radiation after a predetermined time elapses from setting of said signal line to the reference potential by said first power source, and

wherein said control circuit controls said second power source so as to start a supply of electrical power to said preamplifier on the basis of a timing of generating a radiation exposure permission signal.

5. An image sensing apparatus according to claim 4, wherein said exposure permission timer generates the radiation exposure permission signal to said radiation generating apparatus to generate radiation on the basis of a time which is required to obtain a stable state of said sensor.

6. An image sensing apparatus according to claim 4, wherein said exposure permission timer generates the radiation exposure permission signal to said radiation generating apparatus to generate radiation on the basis of a time which is required to obtain a stable state of an offset of said sensor.

7. An image sensing apparatus according to claim 4, wherein said exposure permission timer checks in a real time manner an offset amount of said sensor, and generates the radiation exposure permission signal to said radiation generating apparatus on the basis of the checked offset amount.

8. An image sensing apparatus according to claim 1, wherein said control circuit is further adapted to read data from said sensor, and to control said second power source so as to stop a supply of electrical power to said preamplifier on the basis of a timing of the completion of the read-out operation.

9. An image sensing apparatus according to claim 1, wherein said control circuit controls said first power source so as to set said signal line to the reference potential on the basis of a timing for input of an exposure preparation signal.

10. An image sensing apparatus according to claim 9, wherein said control circuit controls said sensor so as to start an offset correction on the basis of the timing of outputting the exposure preparation signal, and controls said radiation generating apparatus so as to expose the radiation at a timing of completing the offset correction.

11. An image sensing apparatus according to claim 1, further comprising a start command transmitting device adapted to transmit an exposure preparation signal to said radiation generating apparatus and to said control circuit, in accordance with an operation of an operator.

12. An image sensing apparatus according to claim 1, further comprising a start command transmitting device adapted to transmit an exposure preparation signal to said radiation generating apparatus and to said control circuit, through a system storing information relating to radiation.