Special receptacle or package – For plate or sheet – Fragile or sensitive
Reexamination Certificate
2001-09-28
2003-08-12
Fidei, David T. (Department: 3728)
Special receptacle or package
For plate or sheet
Fragile or sensitive
C378S182000, C378S188000
Reexamination Certificate
active
06604633
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a stimulable phosphor sheet having a stimulable phosphor layer and a cassette storing the stimulable phosphor sheet.
2. Description of the Related Art
There has been known a radiation image recording reproducing system using stimulable phosphor which stores a portion of energy of radiation (such as X-rays, a rays, rays, rays, electron rays, and ultraviolet rays) irradiated thereon and emits light in accordance with the energy stored therein upon exposure to excitation light such as visible light (Japanese Unexamined Patent Publication Nos. 55(1980)-12429, 56(1981)-11395, and 56(1981)-11397, for example). In such a system, radiation image information of a subject such as a human body is recorded on a stimulable phosphor sheet and the sheet is scanned with excitation light such as a laser beam to have the sheet emit light. The light is photoelectrically read to obtain an image signal, and a radiation image of the subject is output as a visible image on a recording medium such as a photosensitive material or on a display apparatus such as a CRT, based on the image signal.
As methods of photoelectrically reading the light, single-side reading and double-side reading are known. In single-side reading, an image signal is read only from one side of a stimulable phosphor sheet. In double-side reading, image signals are read respectively from each side of a stimulable phosphor sheet having a layer of stimulable phosphor. The layer is formed on a front side of a transparent base-material sheet comprising a transparent film or the like of 100~500 &mgr;m thickness, for example. Radiation is irradiated from the side of the stimulable phosphor layer on the stimulable phosphor sheet to record radiation image information. The stimulable phosphor sheet is then scanned with excitation light from the side of the stimulable phosphor layer, and light emitted to both a front side (the side of the stimulable phosphor layer) and to a backside (the side of the transparent base material) of the stimulable phosphor sheet is read respectively by photoelectric reading means on the front side and the backside (see Japanese Unexamined Patent Publication No. 55(1980)-87970, for example). In double-side reading, by carrying out an addition process on signals obtained from both sides at pixels corresponding to each other, light collection efficiency improves and noise components are averaged. Therefore, an S/N ratio of a radiation image obtained in this manner can be improved.
In the radiation image recording reproducing system described above, photographing is carried out by using a stimulable phosphor sheet stored in a cassette having a flat shape. In the case where a photographed image is read, the cassette is set on an automatic reading apparatus. The reading apparatus automatically opens the cassette and takes out the stimulable phosphor sheet to carry out reading.
Different cassettes are used for single-side reading and for double-side reading. Therefore, the reading apparatus judges whether a stimulable phosphor sheet stored in a cassette is for single-side reading or for double-side reading, by reading a bar code on the cassette or on the stimulable phosphor sheet. In this manner, appropriate reading is carried out.
For example, if a cassette for double-side reading is set on an automatic reading apparatus, the reading apparatus reads a bar code of the cassette and recognizes that the cassette is for double-side reading. Assuming that a sheet in the cassette is for double-side reading, the reading apparatus then carries out addition processing on image signals read from both sides of the sheet by using a predetermined addition ratio.
However, a conventional cassette for single-side reading and a conventional cassette for double-side reading are substantially identical in appearance, and a stimulable phosphor sheet for single-side reading has substantially the same shape as a stimulable phosphor sheet for double-side reading. Therefore, a stimulable phosphor sheet for single-side reading can often be mistakenly stored in a cassette for double-side reading while a stimulable phosphor sheet for double-side reading can be stored in a cassette for single-side reading.
Furthermore, since the automatic reading apparatus described above is set to carry out the reading process on the premise that a combination of a cassette and a stimulable phosphor sheet is right, the reading apparatus carries out double-side reading by recognizing a bar code on a double-side reading cassette, even if a stimulable phosphor sheet for single-side reading is stored in the cassette by mistake. As a result, the reading apparatus outputs an image signal from the sheet after carrying out addition processing on image signals read from both sides. Since light is not detected from the backside of the stimulable phosphor sheet for single-side reading, no backside image signal is practically added. Therefore, an image represented by the image signal obtained as a result becomes extremely unclear.
Moreover, in the case of a stimulable phosphor sheet for double-side reading having a stimulable phosphor layer on a front side of a transparent base material, the front side is not easily distinguished from a backside thereof, since the base material is transparent. For example, when the sheet is stored in a cassette, the sheet can be mistakenly stored face down in the cassette, although it should be stored in such a manner that the front side of the sheet faces a front side of the cassette (the side which faces a radiation source at the time of photographing).
The reading apparatus scans the stimulable phosphor sheet from the front side, that is, from the side of the stimulable phosphor layer, assuming that the sheet for double-side reading is appropriately stored in the cassette. If the sheet for double-side reading is set face down in the cassette, the reading apparatus actually carries out the scan from the side of the transparent base material, which causes appropriate reading to become difficult due to the scanning via the transparent base material. Consequently, sharpness of an image obtained thereby degrades a great deal.
SUMMARY OF THE INVENTION
The present invention has been conceived based on consideration of the above problems. An object of the present invention is therefore to provide combinations of stimulable phosphor sheets and cassettes therefor, for avoiding a problem of erroneous combination of a stimulable phosphor sheet for double-side reading and a cassette for single-side reading and vice versa.
Another object of the present invention is to provide a combination of a stimulable phosphor sheet for double-side reading and a cassette therefor, for avoiding a problem of face down setting of the double-side reading stimulable phosphor sheet in the cassette.
Combinations of stimulable phosphor sheets and cassettes of the present invention are a combination of a double-side reading stimulable phosphor sheet enabling reading from both sides of the sheet and a cassette for double-side reading having a container area for containing said double-side reading stimulable phosphor sheet, and a combination of a single-side reading stimulable phosphor sheet enabling reading only from one side of the sheet and a cassette for single-side reading having a container area for containing the single-side reading stimulable phosphor sheet. The combinations of the present invention are characterized in that the double-side reading stimulable phosphor sheet has a shape different from the shape of the single-side reading stimulable phosphor sheet and a shape of the container area of the cassette for double-side reading prevents the single-side reading stimulable phosphor sheet from being contained in the cassette due to a difference in the shapes of the sheets.
As the shapes of the sheets and the container area of the cassette for double-side reading, the single-side reading sheet has an additional part not existing in a corresponding position in the double-side r
Fidei David T.
Fuji Photo Film Co. , Ltd.
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