Photoelectric conversion device, radiation detection apparatus, image processing system, and driving method thereof

• US 20020024016A1
• Filed: 07/25/2001
• Published: 02/28/2002
• Est. Priority Date: 07/28/2000
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Endo, Tadao
• Granted Patent: US 6,965,111 B2
• Time in Patent Office: Days
• US Class Current: 250/370.11
• CPC Class Codes: G01T 1/2928 using solid state detectors
• CPC Class Codes: H04N 25/63 applied to dark current
• 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

In a photoelectric conversion device, to suppress alteration of its properties during a long time use, lower decrease of S/N ratio due to a dark current output, and shorten image-pickup cycles. An MIS type photoelectric conversion elements using an amorphous semiconductor material are connected with an electric power source for applying bias (Vs) for photoelectric conversion, an electric power (VREF) for resetting an accumulated electric charge, and a setting point for applying zero bias (VGND) at the time of non-operation of the element through SW1. Emitted x-rays from an x-ray source, which is a first light source, come into collision against a phosphor after being transmitted through an object body to be inspected which is not illustrated in drawings and then are absorbed in the phosphor to be converted to visible light rays. The visible light rays from the phosphor are radiated to the photoelectric conversion elements. Prior to reading out of the x-ray image, an LED light source is lighted. SW2 and SW3 are switches for turning on the x-ray source and the LED light source, respectively. In this embodiment, there are a reading-out period and a non-reading-out period, and the x-ray source is turned on during the reading-out period and the LED light source is turned on during the non-reading-out period.

Claims

1. A photoelectric conversion device, comprising:

a photoelectric conversion substrate composed of a substrate and a plurality of photoelectric conversion elements installed in the substrate;

a light source; and

an outer casing for housing the photoelectric conversion substrate and the light source,

wherein, between a reading-out period for obtaining image data and a non-reading-out period during which reading out is not carried out, the light source is turned on in the non-reading-out period.

2. The photoelectric conversion device according to claim 1, wherein a plurality of switching elements are further installed on the photoelectric conversion substrate.

3. The photoelectric conversion device according to claim 2, wherein the photoelectric conversion elements and the switching elements comprise at least an amorphous silicon layer.

4. The photoelectric conversion device according to claim 1, wherein, the light source is LED, EL, a cathode ray tube, or a semiconductor laser.

5. The photoelectric conversion device according to claim 1, wherein the light source emits light rays having a wavelength region within which the photoelectric conversion elements have light absorption.

6. The photoelectric conversion device according to claim 1, further comprising a wavelength converter for converting radiation to visible light rays.

7. The photoelectric conversion device according to claim 6, wherein the wavelength converter contains at least any one of Gd₂O₂S, Gd₂O₃, or CsI.

8. A photoelectric conversion device, comprising:

a substrate provided with a plurality of photoelectric conversion elements for carrying out photoelectric conversion of incident light rays having image data; and

light sources for radiating light rays having the image data and light rays having no image data to a plurality of the photoelectric conversion elements.

9. The photoelectric conversion device according to claim 8, further comprising a wavelength converter.

10. The photoelectric conversion device according to claim 9, wherein the wavelength converter contains at least any one of Gd₂O₂S, Gd₂O₃, or CsI.

11. The photoelectric conversion device according to claim 8, wherein the light sources are composed of any one of LED, EL, a cathode ray tube, or a semiconductor laser.

13. The image data processing system according to claim 12, further comprising a wavelength converter.

14. The image data processing system according to claim 13, wherein the wavelength converter contains at least any one of Gd₂O₂S, Gd₂O₃, or CsI.

15. The image data processing system according to claim 12, wherein the control means drives the radiation source during a period for reading out image data and operates the light source during a period of not reading out image data.

18. The radiation detection apparatus according to claim 17, further comprising a wavelength converter and wherein light rays from the light source are reflected by the wavelength converter to lead the light rays to the photoelectric conversion elements.

19. The radiation detection apparatus according to claim 17, wherein each of the photoelectric conversion elements comprises a first electrode layer, an insulating layer for inhibiting flow of both of a first carrier and a second carrier with different polarity from that of the first carrier, a photoelectric conversion semiconductor layer, an injection inhibiting layer for inhibiting injection of the first carrier in the semiconductor layer, and a second electrode layer.

12. An image data processing system, comprising:

a photoelectric conversion device comprising a substrate provided with a plurality of photoelectric conversion elements and a light source for radiating light rays having no image data to a plurality of the photoelectric conversion elements;

a radiation source; and

control means for independently controlling the radiation source and the photoelectric conversion device.

16. A driving method of an image data processing system which comprises a first and a second light sources, a semiconductor element having a semiconductor layer having an absorption region in a wavelength of light rays radiated from the second light source, and control means for independently controlling the first and the second light sources, comprising the steps of:

radiating light rays of the first light source during an image-pickup period and reading out image data; and

radiating light rays of the second light source during an non-image-pickup period.

17. A radiation detection apparatus, comprising:

a photoelectric conversion substrate composed of a substrate and a plurality of photoelectric conversion elements installed in the substrate; and

an outer casing housing the photoelectric conversion substrate,

wherein the outer casing further contains a light source.