Stock material or miscellaneous articles – Composite – Of polyamidoester
Reexamination Certificate
2000-07-18
2002-07-23
Seidlack, James J. (Department: 1711)
Stock material or miscellaneous articles
Composite
Of polyamidoester
C428S425900, C428S551000, C427S160000
Reexamination Certificate
active
06423413
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a radiation image storage panel utilizing light emission characteristics of a stimulable phosphor.
2. Description of the Related Art
In lieu of conventional radiography, radiation image recording and reproducing techniques utilizing a stimulable phosphor have heretofore been used in practice. The radiation image recording and reproducing techniques are described in, for example, U.S. Pat. No. 4,239,968. The radiation image recording and reproducing techniques utilizes a radiation image storage panel (referred to also as the stimulable phosphor sheet) provided with a stimulable phosphor. With the radiation image recording and reproducing techniques, the stimulable phosphor of the radiation image storage panel is caused to absorb radiation, which carries image information of an object or which has been radiated out from a sample, and thereafter the stimulable phosphor is exposed to an electromagnetic wave (stimulating rays), such as visible light or infrared rays, which causes the stimulable phosphor to produce the fluorescence (i.e., to emit light) in proportion to the amount of energy stored thereon during its exposure to the radiation. The produced fluorescence (the emitted light) is photoelectrically detected to obtain an electric signal. The electric signal is then processed, and the processed electric signal is utilized for reproducing a visible image.
The radiation image recording and reproducing techniques have the advantages in that a radiation image containing a large amount of information can be obtained with a markedly lower dose of radiation than in the conventional radiography. Also, ordinarily, the radiation image recording and reproducing techniques are performed with built-in types of radiation image recording and read-out apparatuses comprising, built in a single apparatus, (a) means (recording means) for irradiating radiation, which carries image information, to the radiation image storage panel and thereby recording a radiation image on the radiation image storage panel, (b) means (read-out means) for exposing the radiation image storage panel, on which the radiation image has been stored, to the stimulating rays, which cause the radiation image storage panel to emit light in proportion to the amount of energy stored thereon during its exposure to the radiation, and photoelectrically detecting the emitted light to obtain an electric signal (an image signal), (c) means (erasing means) for irradiating erasing light to the radiation image storage panel, from which the image signal has been detected, and thereby erasing information remaining on the radiation image storage panel, and (d) a conveyance system, which connect the recording means, the read-out means, and the erasing means to one another and conveys the radiation image storage panel among them. The erased radiation image storage panel can be used again for the recording of a radiation image. Therefore, the radiation image storage panel is used repeatedly. Particularly, in the radiation image recording and read-out apparatuses described above, the radiation image storage panel is conveyed repeatedly, circulated, and used for the recording of a radiation image within the apparatus. Accordingly, the radiation image recording and reproducing techniques is efficient particularly for direct medical radiography, such as the X-ray image recording for medical diagnosis.
Ordinarily, the radiation image storage panel utilized for the radiation image recording and reproducing techniques has a basic structure comprising a substrate and a stimulable phosphor layer overlaid on one surface of the substrate. Ordinarily, the radiation image storage panel has a rectangular sheet-like shape. Also, ordinarily, a transparent protective film is formed on the surface of the stimulable phosphor layer, which surface is opposite to the surface that stands facing the substrate. The transparent protective layer protects the stimulable phosphor layer from chemical deterioration or physical shocks.
The stimulable phosphor layer comprises a binder and stimulable phosphor particles dispersed in the binder. The stimulable phosphor has the properties such that, when the stimulable phosphor is caused to absorb radiation, such as X-rays, and is then exposed to an electromagnetic wave (stimulating rays), such as visible light or infrared rays, the stimulable phosphor emits light in proportion to the amount of energy stored thereon during its exposure to the radiation. Therefore, when the radiation image storage panel is exposed to the radiation, which carries image information of an object or which has been radiated out from a sample, the stimulable phosphor layer of the radiation image storage panel absorbs the radiation in proportion to the dose of radiation, and a radiation image of the object or the sample is stored as an image (a latent image) of energy from the radiation on the radiation image storage panel. The radiation image storage panel is then exposed to the electromagnetic wave, and the image having been stored on the radiation image storage panel can be detected as the light emitted by the radiation image storage panel. The emitted light is detected photoelectrically to obtain an image signal, the image signal is processed, and the thus obtained processed image signal can then be utilized for reproducing the radiation image of the object or the sample as a visible image.
As described above, the radiation image recording and reproducing techniques are the advantageous image forming techniques. However, as in the cases of an intensifying screen employed in the conventional radiography, it is desired that the radiation image storage panel utilized for the radiation image recording and reproducing techniques has a high sensitivity and can yield an image of good image quality (with respect to sharpness, graininess, and the like).
It is described in, for example, U.S. Pat. No. 4,346,295 and Japanese Unexamined Patent Publication No. 59(1984)-162499, that a radiation image storage panel capable of yielding an image of good image quality can be obtained by altering the ratio of a binder and a stimulable phosphor to each other with respect to the depth direction of the radiation image storage panel. Also, as a radiation image storage panel suitable for a technique for detecting light emitted from opposite surfaces of a radiation image storage panel and thereby detecting two image signals from the opposite surfaces of the radiation image storage panel, a radiation image storage panel has been proposed in, for example, Japanese Unexamined Patent Publication No. 7(1995)-287099, wherein the distribution of a binder and the distribution of ultramarine in a stimulable phosphor layer are biased to one side of the stimulable phosphor layer, such that the sharpness and graininess characteristics of an obtained radiation image may be improved.
As one of producing processes for obtaining the distribution described above, a producing process has been known, wherein a stimulable phosphor sublayer is formed on a temporary substrate having been applied with a releasing agent and is then separated from the temporary substrate, and a plurality of stimulable phosphor sublayers having thus been obtained are overlaid one upon another to form a stimulable phosphor layer. With the producing process, such that an image having good image quality can be obtained, a temporary substrate contact side surface of a stimulable phosphor sublayer, which surface was in contact with the temporary substrate when the stimulable phosphor sublayer was formed on the temporary substrate, and a temporary substrate contact side surface of an adjacent stimulable phosphor sublayer are adhered to each other. However, when the stimulable phosphor sublayer is formed on the temporary substrate, stimulable phosphor particles having a large specific gravity sink to the lower side, and the binder floats to the upper surface of the stimulable phosphor sublayer. As a result, at the temporary substrate contact
Bissett Melanie
Fuji Photo Film Co. , Ltd.
Seidlack James J.
LandOfFree
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