Radiant energy – Source with recording detector
Reexamination Certificate
2001-04-02
2002-10-22
Hannaher, Constantine (Department: 2878)
Radiant energy
Source with recording detector
C250S591000, C250S484400, C250S370010, C250S370090
Reexamination Certificate
active
06469312
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The subject matters disclosed in this specification are related to the subject matters disclosed in the following copending, commonly-assigned U.S. patent applications:
(1) U.S. Ser. No. 09/136,739 filed by Shinji Imai on Aug. 19, 1998, now U.S. Pat. No. 6,268,614 and entitled “ELECTROSTATIC RECORDING MEMBER, ELECTROSTATIC LATENT IMAGE RECORDING APPARATUS, AND ELECTROSTATIC LATENT IMAGE READ-OUT APPARATUS,” corresponding to Japanese patent application No. 10-232824, which is disclosed in Japanese Unexamined Patent Publication No. 2000-105297; and
(2) U.S. Ser. No. 09/385,443 filed by Satoshi Arakawa on Aug. 30, 1999 and entitled “RADIATION IMAGE DETECTING SYSTEM,” corresponding to Japanese patent application No. 10-243379, which is disclosed in Japanese Unexamined Patent Publication No. 2000-137080.
The contents of the above copending, commonly-assigned U.S. patent applications and the corresponding Japanese patent applications are incorporated in this specification by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an energetic-beam detection apparatus which absorbs an energetic beam by using an energetic-beam absorber made of selenium, where the energetic beam may be a beam of light, X rays, gamma rays, any other electromagnetic waves having shorter or longer wavelengths, and energetic particles.
2. Description of the Related Art
In various systems which have been proposed or used, an energetic-beam detection apparatus including a selenium detector is used, where the selenium detector is made of selenium as an energetic-beam absorber which is sensitive to energetic beams. In the field of medical radiography, radiographic image readout systems using an energetic-beam detection apparatus which can efficiently detect radiation have been proposed in order to decrease radiation doses to which patients are exposed, and improve performance in diagnosis. In the above radiographic image readout systems, charges having an amount corresponding to the intensity of radiation which has passed through a subject (patient) is stored as latent-image charges in a photoconductive layer in a solid-state radiation detector so that a radiographic image is recorded, where the solid-state radiation detector is a kind of selenium detector. There are two methods of reading out an image signal which represents the amount of the latent-image charges, the TFT readout method and the optical readout method.
Since the above photoconductive layer exhibits conductivity when the photoconductive layer is exposed to radiation such as X rays, the photoconductive layer is also called an X-ray photoconductive layer. However, in this specification, the term “photoconductive layer” is used in its broadest sense, i.e., the term “photoconductive layer” covers any photoconductive layers which exhibit conductivity when the photoconductive layers are exposed to light, X rays, gamma rays, or any other electromagnetic radiation having a shorter or longer wavelength.
According to the TFT readout method, TFTs (thin-film transistors) are scanned and activated, the latent-image charges stored in the photoconductive layer is converted into a radiographic image signal, which is then output. For example, the coassigned U.S. patent application Ser. No. 09/385,443 corresponding to Japanese Unexamined Patent Publication No. 2000-137080 discloses a solid-state radiation detector which is constructed by forming a first electrode, a photoconductive layer, a plurality of charge collecting electrodes, a capacitor array, a TFT array, and a second electrode in this order on a fluorescent layer. In the solid-state radiation detector, the fluorescent layer emits visible light when the fluorescent layer is exposed to radiation. The first electrode is transparent to the radiation and the visible light. The photoconductive layer contains a-Se (amorphous selenium) as a main component, and has a thickness of about 400 micrometers. The plurality of charge collecting electrodes respectively correspond to pixels, and are arranged in the form of a matrix with a predetermined pitch on an insulator substrate being made of quartz glass and having a thickness of 3 mm. The capacitor array includes a plurality of capacitors each of which stores as latent-image charges signal charges collected by a corresponding one of the plurality of charge collecting electrodes. The TFT array includes a plurality of TFTs, each of which transfers the latent-image charges stored in a corresponding one of the plurality of capacitors to a detection circuit. For example, the fluorescent layer contains Gd
2
O
2
S:Tb as a main component, and has a thickness of about 100 micrometers. It is preferable to arrange the fluorescent layer in contact with or in the vicinity of the first electrode. The photoconductive layer generates charges when the photoconductive layer is exposed to the above visible light as well as the above radiation which carries image information.
When the fluorescent layer is exposed to the radiation which carries image information, a portion of the radiation is converted into visible light in the fluorescent layer. The remaining portion of the radiation and the visible light converted from the radiation enter the photoconductive layer through the first electrode. Since the photoconductive layer generates charges when the photoconductive layer is exposed to either of visible light and radiation, charges corresponding to the image information carried by the visible light and the remaining portion of the radiation are generated in the photoconductive layer when the visible light and the remaining portion of the radiation enter the photoconductive layer. Then, the generated charges are read out through the TFTs. The above solid-state radiation detector is advantageous in that a high-quality radiographic image can be obtained. Since the photoconductive layer in the above solid-state radiation detector contains a-Se as a main component, the solid-state radiation detector can be regarded as selenium detector.
On the other hand, according to the optical readout method, the latent-image charges stored in the photoconductive layer are converted into an image signal by applying reading light to the solid-state radiation detector, and then the image signal is read out. For example, the optical readout method is disclosed in U.S. Pat. Nos. 4,176,275, 5,268,569, 5,354,982, 4,535,468, and 4,961,209, Research Disclosure No. 23027, June 1983 (“Method and device for recording and transducing an electromagnetic energy pattern”), Japanese Unexamined Patent Publication No. 9(1997)-5906, and Medical Physics, Vol. 22, No. 12 (“X-ray imaging using amorphous selenium”).
For example, U.S. Pat. No. 4,535,468 discloses a solid-state radiation detector which is constructed by forming a recording-side photoconductive layer, an intermediate layer (trap later), a reading-side photoconductive layer, and a reading-side electrode layer in this order on a recording-side electrode layer. The recording-side electrode layer is relatively thick (2 mm thick) and made of aluminum, and behaves as a conductive substrate which is transparent to a recording electromagnetic radiation (hereinafter called recording light). The recording-side photoconductive layer contains a-Se (amorphous selenium) as a main component, and has a thickness of 100 to 500 micrometers. The intermediate layer (trap later) is made of AsS
4
, As
2
S3, As
2
Se
3
, or the like, and has a thickness of 0.01 to 10.0 micrometers. Latent-image charges generated in the recording-side photoconductive layer are trapped and stored in the intermediate layer (trap later). The reading-side photoconductive layer contains a-Se (amorphous selenium) as a main component, and has a thickness of 0.5 to 100 micrometers. The reading-side electrode layer is made of gold or ITO (indium tin oxide), has a thickness of 100 nm, and behaves as a conductive substrate which is transparent to a reading electromagnetic radiation (hereinafter called reading light). The above sol
Gagliardi Albert
Hannaher Constantine
LandOfFree
Energetic-beam detection apparatus including... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Energetic-beam detection apparatus including..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Energetic-beam detection apparatus including... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2999047