Radiant energy – Source with recording detector – Using a stimulable phosphor
Reexamination Certificate
2001-11-07
2004-08-10
Hannaher, Constantine (Department: 2878)
Radiant energy
Source with recording detector
Using a stimulable phosphor
C250S582000
Reexamination Certificate
active
06774386
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an image information read-out apparatus, and more particularly to an image information read-out apparatus in which reading light is projected in a line onto an image-bearing medium bearing thereon an image and image-bearing light bearing thereon the image on the image-bearing medium and emitted from the recording medium upon exposure to the reading light is read out by a line sensor.
2. Description of the Related Art
When certain kinds of phosphor are exposed to a radiation, they store a part of energy of the radiation. Then when the phosphor which has been exposed to the radiation is exposed to stimulating rays such as visible light or a laser beam, light is emitted from the phosphor in proportion to the stored energy of the radiation. A phosphor exhibiting such properties is generally referred to as “a stimulable phosphor”. In this specification, the light emitted from the stimulable phosphor upon stimulation thereof will be referred to as “stimulated emission”. There has been put into wide use as a computed radiography a radiation image recording and reproducing system using a stimulable phosphor sheet (a sheet provided with a layer of the stimulable phosphor).
In the radiation image recording and reproducing system, a stimulable phosphor sheet is exposed to a radiation passing through an object such as a human body to have a radiation image information of the object stored on the stimulable phosphor sheet, a stimulating light beam such as a laser beam is caused to two-dimensionally scan the stimulable phosphor sheet, thereby causing each part of the stimulable phosphor sheet exposed to the stimulating light beam to emit the stimulated emission, the stimulated emission is photoelectrically detected, thereby obtaining an image signal (a radiation image signal) representing the radiation image information, the radiation image signal thus obtained is subjected to image processing such as gradation processing and/or frequency processing and a radiation image of the object is reproduced as a visible image for diagnosis on the basis of the processed radiation image signal on a recording medium such as a photographic film or a display such as a CRT.
In the radiation image information read-out apparatus employed in the radiation image recording and reproducing apparatus, it has been proposed to use a line light source which projects a line beam onto the stimulable phosphor sheet as a stimulating light source and to use a line sensor having an array of photoelectric convertor elements extending in the main scanning direction (the longitudinal direction of the line beam) as a means for photoelectrically reading out the stimulated emission. The line beam and the line sensor are moved relative to the stimulable phosphor sheet in the sub-scanning direction (the direction perpendicular to the longitudinal direction of the line beam) by a scanning means. By the use of a line beam and a line sensor, the reading time is shortened, the overall size of the apparatus can be reduced and the cost can be reduced. See, for instance, Japanese Unexamined Patent Publication Nos. 60 (1985)-111568, 60 (1985)-236354, and 1 (1989)-101540. In such a radiation image information read-out apparatus, the line sensor is positioned close to the stimulable phosphor sheet and an erecting unit optical system is provided between the line sensor and the stimulable phosphor sheet in order to collect the stimulated emission on the light receiving face of the line sensor.
Also when the stimulating light source is a point scan type light projecting means which causes a light beam to scan the stimulable phosphor sheet, a line sensor is sometimes employed as the photoelectric read-out means.
The length of the line sensor should be equivalent to the width of the stimulable phosphor sheet which is generally 35 cm to 43 cm. Since the sensor chips commercially available at present is from several tens mm to about 100 mm in length, a line sensor formed by arranging a plurality of sensor chips in a row has been employed in the radiation image information read-out apparatus. Since each of the sensor chips is packaged, the parts between adjacent sensor chips form dead zones (noneffective zones) where the stimulated emission cannot be detected. Accordingly, stimulated emission which impinges upon the noneffective zones of the line sensor cannot be detected, which generates artifact in images obtained.
This problem may be overcome by arranging a plurality of combinations of a line sensor (having noneffective zones) and an erecting unit optical system in parallel to the longitudinal direction of the line beam. However this approach is disadvantageous in that one or more additional erecting unit optical system is required, which adds to the cost, and even with such a structure, the noneffective zones of the respective line sensors make it difficult to uniform the light receiving condition over the entire length of the line beam.
In the field of biochemistry and the molecular biology, there has been known a fluorescence detecting system in which detection of the gene sequence, the gene expression level, and the pathway and/or condition of metabolism, absorption and excretion of material administered to a mouse; and separation, identification, and evaluation of molecular weight and properties of protein can be carried out by reading out image information on a sample in which a specific organism-derived material labeled with fluorescent pigment is distributed. In the fluorescence detecting system, for example, a gel support on which a specific DNA fraction (an organism-derived material) labeled with fluorescent pigment is distributed is obtained, exciting light which excites the fluorescent pigment is projected onto the gel support, fluorescence emitted from the gel support is photoelectrically read, thereby obtaining image information representing the distribution of the DNA fraction labeled with the fluorescent pigment, and the distribution of the DNA fraction is displayed on, for instance, a CRT display on the basis of the image information thus obtained.
Also in this fluorescence detecting system, there has been proposed an arrangement which comprises a stimulating (exciting) light source, a line sensor and a sub-scanning means similar to those employed in the aforesaid radiation image information read-out apparatus. Also in the fluorescence detecting system of this arrangement, there are involved problems described above in conjunction with the radiation image information read-out apparatus.
SUMMARY OF THE INVENTION
In view of the foregoing observations and description, the primary object of the present invention is to provide an image information read-out apparatus which employs a line sensor formed of a plurality of sensor chips and can nevertheless read an image free from artifact due to the noneffective zones between sensor chips.
In accordance with the present invention, there is provided an image read-out apparatus comprising a reading light projecting means which projects reading light in a line-like pattern extending in a main scanning direction onto an image-bearing medium bearing thereon image information, an image-bearing light detecting means having a line sensor which extends along the line-like portion of the image-bearing medium exposed to the reading light to receive image-bearing light emitted from the portion exposed to the reading light and converts the amount of image-bearing light to an electric signal, and a sub-scanning means which moves one of the image-bearing light detecting means and the image-bearing medium relatively to each other in a sub-scanning direction intersecting the main scanning direction, wherein the improvement comprises that
the image-bearing light detecting means further comprises an erecting unit optical system which is disposed along the portion of the image-bearing medium exposed to the reading and focuses the image-bearing light on the line sensor and an optical element array formed by a plurality of first
Fuji Photo Film Co. , Ltd.
Hannaher Constantine
Moran Timothy J.
Sughrue & Mion, PLLC
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