JPH04100000A - Accumulative fluorescent sheet and cassette for containing the sheet - Google Patents

Abstract

PURPOSE:To omit suction-holding means of a reader, to minimize the reader and reduce the cost of the reader by constituting an accumulative fluorescent sheet in a part of cylinder and containing it in a cassette consisting of a box having a holding surface curved along the sheet. CONSTITUTION:To red an accumulative fluorescent sheet 11 with a radiation image reader of optical scanner type without using ftheta lens in the optical system, the fluorescence layer to store image information is so formed as to be a curved surface of a part of cylinder along the scanning line of arc on which a light beam focuses. For this purpose, the base body (a) to stuck a fluorescent layer (b) is made of a stiff material maintaining the curved shape for example, film of high polymer like polyester or metal sheet, etc. And by containing the sheet 11 in a cassette 17 consisting of a box having a curved holding surface along the sheet 11 and a lid 23, the transportation is made easy. By this, lifting and slipping of the sheet 11 from the holding surface of the reader are prevented and so, a complicated holding means like a suction-holding means or the like is omitted.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a stimulable phosphor sheet.

Furthermore, the present invention relates to a cassette that is a storage container for the stimulable phosphor sheet.

<Prior Art> As a method of obtaining a radiographic image as an image, recently, a radiographic image information recording and reproducing system using a stimulable phosphor has attracted attention as an alternative to a radiographic system.

Here, stimulable phosphor refers to radiation (X-rays, α-rays, β-rays,
When irradiated with γ-rays, electron beams, ultraviolet rays, etc., part of the energy of this radiation is accumulated, and then when excited light such as visible light is irradiated, it emits stimulated luminescence according to the accumulated energy. A phosphor that exhibits

Using this phosphor, radiation image information of a subject such as a human body is stored and recorded on a sheet having a layer of stimulable phosphor (hereinafter referred to as a ``stimulable phosphor sheet''), and this sheet is exposed to excitation light. A radiographic image in which the stimulated luminescent light is scanned by a scanner to generate stimulated luminescence, the generated stimulated luminescent light is read photoelectrically and converted into an electrical signal to obtain an image signal, and this image signal is processed to obtain a radiographic image of the subject that is suitable for diagnosis. A recording and reproducing system has been proposed by the present applicant.

Generally, the structure of the above-mentioned stimulable phosphor sheet is as shown in FIG. A protective layer 4 for physically or chemically protecting the surface of the support 2 and a backing layer 5 provided on the back surface of the support 2 are laminated together. As possible, it has flat plate-like flexibility (see, for example, Japanese Patent Application Laid-Open No. 146447/1983).

Furthermore, in Japanese Patent Application Laid-Open No. 62-246011, the present applicant has developed a method in which a flat flexible phosphor sheet is held in a substantially arc shape, and scanning with a light beam deflected by an optical deflector is possible. We are proposing a light beam scanning device based on this technology.

This device images a deflected light beam on a substantially arc-shaped main scanning line using a normal imaging lens (ftan theta lens) without using an f theta lens. A phosphor sheet having a phosphor sheet is curved into a substantially circular arc shape in the main scanning direction, held at a predetermined angle, and is swung in a substantially circular arc shape by a light deflector to perform main scanning.
At the same time, sub-scanning is performed by moving the sub-scanning mirror in a direction (sub-scanning direction) substantially orthogonal to the main-scanning curve on a substantially circular arc.

In this light beam scanning device, as mentioned above, the flexible phosphor sheet, which is flat in the normal state, is curved into a substantially arc shape in the main scanning direction and held at a predetermined angle. The body sheet is positioned so as to be capable of main scanning and sub-scanning by the light beam by a holding means having a substantially cylindrical holding surface curved in the main scanning direction and inclined at a predetermined angle with respect to the light beam. . moreover,
The holding means is provided with a suction means for holding the stimulable phosphor sheet in a substantially arc shape while tilting the stimulable phosphor sheet at a predetermined angle with respect to the light beam, so that the phosphor sheet does not float above the holding surface. This prevents proper optical scanning from being hindered due to misalignment.

<Problems to be Solved by the Invention> However, in the light beam scanning device described in JP-A No. 62-246011, in order to adsorb and maintain the phosphor sheet on a holding surface curved in an approximately arc shape, suction is required. This requires means and the like, making the device itself complicated and large, which ultimately becomes a factor in increasing costs.

It is an object of the present invention to provide a stimulable phosphor sheet and a stimulable phosphor sheet that can solve the above-mentioned problems in the light beam scanning type device, omit a suction means, etc., and reduce the size and cost of the device. We will provide you with a cassette to use.

<Means for Solving the Problems> In order to achieve the above object, according to a first aspect of the present invention, a support and a phosphor layer provided on the support for storing and recording radiation image information are provided. Provided is a stimulable phosphor sheet characterized in that it has a substantially cylindrical shape.

Further, according to the second aspect of the present invention, the first aspect of the present invention
A cassette for storing a stimulable phosphor sheet according to the aspect of the present invention, comprising: a casing for accommodating the stimulable phosphor sheet and having a holding surface curved along the stimulable phosphor sheet; To provide a cassette, characterized in that the cassette is attached to the cassette so as to be openable and closable, and is configured with a lid body which is curved in accordance with the curved holding surface.

<Operation of the Invention> The stimulable phosphor sheet of the first aspect of the present invention has a support and a phosphor layer for storing and recording radiographic image information so as to have a substantially cylindrical shape. Such a stimulable phosphor sheet having a substantially cylindrical support and a phosphor layer needs to have a non-flexible structure because the phosphor layer has a substantially cylindrical surface. It is possible to have the phosphor layer or the support layer. Therefore, when this rigid stimulable phosphor sheet is placed, for example, on the holding surface of a light beam scanning device as described above, the stimulable phosphor sheet is placed so that it matches the main scanning curve as in the past. There is no need to provide complicated holding means such as suction means to prevent the stimulable phosphor sheet from lifting up from the holding surface and from sliding off the inclined holding surface.

This leads to the simplification and further miniaturization of the light beam scanning device.

A cassette according to a second aspect of the present invention that stores the stimulable phosphor sheet of the first aspect is a casing that stores the stimulable phosphor sheet and has a holding surface curved along the stimulable phosphor sheet. The stimulable phosphor sheet can be stored in a compact manner because the stimulable phosphor sheet is comprised of a lid body that is attached to the housing so as to be openable and closable and is curved to match the curved holding surface.

<Embodiments> Hereinafter, a stimulable phosphor sheet and a cassette containing the same according to the present invention will be described in detail based on preferred embodiments shown in the accompanying drawings.

FIG. 1 is a perspective view showing an embodiment of the stimulable phosphor sheet of the first aspect of the present invention, and FIG. FIG. 3 is a perspective view of a cassette showing an embodiment of this aspect, and FIG. 3 is a partially sectional side view of the cassette shown in FIG.

As shown in FIG. 1, a stimulable phosphor sheet 11 of the present invention
This is a stack of a support a and a phosphor layer provided thereon. Furthermore, if necessary, a protective layer C1 or a back layer d is provided on the back surface of the support a for physically or chemically protecting the surface of the phosphor layer. When this stimulable phosphor sheet 11 is read by an optical scanning type radiation image reading device that does not use an fθ lens or the like in the scanning optical system, the light beam is aligned on a predetermined approximately circular arc with respect to the main scanning direction. Because the image is formed, the phosphor layer on which image information is stored and recorded has a substantially cylindrical curved surface along the main scanning line forming a substantially circular arc on which the light beam forms the image. Form a curved surface that envelops a curve conjugate to a circular arc. In order to maintain such a curved shape of the sheet, it is preferable that the support body a is made of a relatively rigid material that does not deform. Alternatively, it is also possible to configure the phosphor layer to be relatively rigid without deformation. The degree of curvature of the stimulable phosphor sheet is determined depending on the focal length of the imaging lens that forms the scanning light beam.

In this case, the support a can be made of a conventionally known support material as long as it has enough rigidity to maintain the curved shape, such as cellulose acetate, polyester, polyethylene, etc. Terephthalate, polyamide, polyimide, triacetate,
Various polymer materials such as polycarbonate, (plastics) films, metal sheets such as aluminum foil and aluminum alloy foil, resin coated paper, pigment paper containing pigments such as titanium dioxide, paper sized with polyvinyl alcohol, etc. Examples include paper, glass, alumina, zirconia, magnesia, titania, and other ceramic plates or sheets.

Furthermore, the support a can also be formed of a shape memory resin or the like, or a magnetic material and a resin containing a magnetic material or magnetic powder. As the shape memory resin that can be applied to the present invention, any of a variety of known shape memory resins can be used. No. 62-192440,
JP-A-63-179956, JP-A-63-54460
Examples include various shape memory resins disclosed in publications such as No.

Note that the color of the support a may be black, gray, white, or metallic, but in this case, a light-absorbing substance such as carbon black is kneaded into the plastic material constituting the support 2. Alternatively, a light-reflecting substance such as titanium dioxide may be incorporated.

The phosphor layer is formed of a binder made of an organic polymer material such as nitrocellulose, and stimulable phosphor particles dispersed in the binder. In addition, the phosphor layer may be composed only of stimulable phosphor aggregates without a binder, or a phosphor layer in which a polymer substance is impregnated into the gaps between stimulable phosphor aggregates. etc. As the stimulable phosphor that can be applied to the present invention, any of various known stimulable phosphors can be used.
No. 9-47289, No. 59-56479, No. 59-5
No. 6480, No. 59-75200, No. 60-8438
Examples include various stimulable phosphors disclosed in publications such as No. 1 and No. 60-166379.

Among the above-mentioned stimulable phosphors, divalent europium-activated alkaline earth metal halide phosphors and rare earth element-activated rare earth oxyhalide phosphors are particularly preferred because they exhibit high-intensity stimulated luminescence. However, the stimulable phosphor used in the present invention is not limited to the above-mentioned phosphors, and any phosphor that exhibits stimulated luminescence when irradiated with radiation and then irradiated with excitation light can be used. There may be.

The particles of such a stimulable phosphor have an average particle size of 0.1 to 1
The stimulable phosphor sheet is appropriately selected from among those having a diameter of about 0.00 μm, and its blending amount is appropriately determined in consideration of the storage capacity, output capacity, etc. of the stimulable phosphor sheet.

As the binder for the above phosphor layer, binders used for normal layer formation can be used, including nitrocellulose, linear polyester, polyalkyl (meth)acrylate, a mixture of nitrocellulose and linear polyester, and nitrocellulose. and polyalkyl (meth)acrylate. Note that these binders may be crosslinked with a crosslinking agent.

Furthermore, the phosphor layer may be provided with an adhesion-imparting layer, a light-reflecting layer, a light-absorbing layer, or the like using a conventionally known method and material. The thickness of the phosphor layer varies depending on the characteristics of the intended radiation image conversion panel 10, the type of phosphor, the mixing ratio of the binder and the phosphor, etc., but is usually 20 μm.
The length should be between 1 mm and 1 mm. However, the layer thickness is preferably 50 to 500 LLm.

Furthermore, the protective layer C is made of a material having a light transmittance that does not interfere with reading, preferably a transparent material, such as polyethylene terephthalate, polyethylene,
It is formed from a film of polyvinylidene chloride, polyamide, or a cellulose derivative.

Further, the back layer d is preferably made of polypropylene or the like.

In this specification, the protective layer C side will be described as the front surface 13 of the stimulable phosphor sheet 11, and the back layer d side will be described as the back surface 15 of the stimulable phosphor sheet. Further, in the stimulable phosphor sheet 11, the portion where image information is substantially recorded is called an image recording area A, and as described above, this image recording area A corresponds to almost the entire surface of the stimulable phosphor sheet 11. If, or
It may correspond to a predetermined part.

Although preferred examples of the stimulable phosphor sheet according to the present invention have been described above, the shape of the stimulable phosphor sheet of the present invention is not limited to the above-mentioned preferred examples.

What is important here is that the surface of the phosphor layer that is scanned by light is a substantially cylindrical curved surface along the substantially arc-shaped main scanning line, and as long as this point is satisfied, various changes can be made. It is.

The cassette 17 for storing the above-mentioned stimulable phosphor sheet 11 of the present invention has an internal space 19 for storing the stimulable phosphor sheet 11, as shown in the preferred example of FIGS. 2 and 3. A lid body 23 is rotatably attached to one side of the housing 21 by, for example, a hinge 25. Note that opening and closing of the front casing is not limited to rotation.

In the illustrated preferred example, the casing 21 and the lid 23 are entirely curved to follow the curved surface of the stimulable phosphor sheet 11 to be housed. That is, in the case 21 of the cassette 17, the frame members 18a and 18b on both side surfaces with respect to the front and rear surfaces and the bottom wall 20 constituting the holding surface are respectively curved at a predetermined ratio, and the lid body 23 is curved in the same way. In this case, the frame members 22a and 22b on both side surfaces and the upper wall 24 are each curved at a predetermined ratio.

The degree of curvature for these does not necessarily have to be a curved surface that envelops a curve that is conjugate to the approximately circular arc scanned by the light beam, but it is necessary to ensure that the phosphor layer of the curved stimulable phosphor sheet and the protective layer thereon are at least curved. It is preferable that the cassette has a shape that is reasonable enough to be held, and that allows for good transportation and storage without increasing the bulk of the cassette itself.

By rotating the lid 23 relative to the housing 21, the lid 23 and the housing 21 are opened and closed. Lid body 2
It is preferable that the structure is such that the stimulable phosphor sheet 11 is kept light-tight when the stimulable phosphor sheet 3 is closed. The housing 21 and the lid 23 are made of acrylonitrile-butadiene-styrene copolymer (ABS resin), vinyl chloride resin,
It is made of synthetic resin such as polypropylene or metal such as aluminum, but it can also be made of magnetic material or resin containing magnetic material.

Inside the lid 23, the stimulable phosphor sheet 11 is stored in a cassette 17, excluding the joint part with the casing 21, and the lid 23 is placed inside the lid 23.
3 when closed, hold down the stimulable phosphor sheet 11,
A pressing member 32 for preventing the stimulable phosphor sheet 11 from shifting or floating is attached by adhesive or the like.

If this pressing member 32 is attached to the entire inside of the lid body 23 except for the joint part with the housing 21, it is possible to press the stimulable phosphor sheet evenly. The presser members may be attached to multiple locations. The presser member 32 is preferably made of a resilient material such as rubber, urethane, sponge, or synthetic resin foam such as styrene foam.

Further, in the illustrated example, the holding member is provided only on the earth wall side, but the holding member may also be provided on the bottom wall side. Furthermore, in addition to the above-mentioned holding member, a housing 21 is provided so that the stimulable phosphor sheet can be easily taken out from the cassette.
A sliding material may be provided on the bottom wall 20 and the top wall 24 of the lid body 23 on the sides facing the internal space. In this case, the pressing member 32 described above is omitted.

Further, a locking mechanism 27 is provided so that the lid body 23 is locked in a closed state. This locking mechanism 27 is
For example, as shown in FIG. 3, the lever part and the claw part have an abbreviated claw member 29, and the claw member 29 is viewed from the open side (hereinafter referred to as "front") opposite to the hinge of the cassette. It is composed of a guide member 31 that slides in the front-rear direction (horizontal direction in FIG. 3), and a spring 33 that is housed within the guide member 31 and biases the claw member toward the front of the cassette.

A portion of the lever of the claw member 29 protrudes to the outside through an opening formed on the top surface of the lid, and the claw portion N of the claw member 29 penetrates the locking portion 35 of the lid 23, and furthermore, the tip of the claw N is the housing 21
It is inserted into a hole 37 formed in the inner part of the front surface of the cassette.

In this locking mechanism 27, when a portion of the lever is pressed in the direction of the arrow in FIG. 3 against the elastic force of the spring 33, the claw member 29 slides along the guide member 31, and the tip of the claw N comes out of the hole 37, and the lock is released.

In addition, the locking mechanism may be a mechanism in which the claw portion of an elastically bent claw member is elastically engaged and locked in a groove provided on the front side of the casing. In this case, the resin is integrally It is easy to manufacture and inexpensive because it can be formed by molding.

Furthermore, when the casing 21 and the lid 23 are made of a magnetic material and a magnetic material-containing resin, even if the locking mechanism is omitted, sufficient magnetic force is generated between the casing 21 and the lid 2 to lock the casing 21 and the lid 23.
3 and can produce an effect similar to that of a locking mechanism. In addition, if the housing 21 and the lid 23 are not magnetic or magnetic-containing resin, either a magnetic sheet or a magnetic material is attached to the joint between the lid 23 and the housing 21, or one of them is It can also be attached as a locking mechanism.

In the interior space of the cassette 17, a stimulable phosphor sheet 11 is provided.
The stimulable phosphor sheet 11 is stored so that the back surface 15 of the stimulable phosphor sheet 11 contacts the bottom of the housing 21, that is, the front surface of the sheet faces upward.

When storing the stimulable phosphor sheet 11 in the cassette 17, the lid 23 of the cassette 17 is closed (the third
From the state shown in the figure), press the lever part of the claw member 29 in the direction of the arrow in the figure, pull out the tip of the claw part N from the hole 37 to unlock the locking mechanism 27, and at the same time, the suction mechanism having a suction mechanism The lid 23 is opened by suctioning and lifting the lid 23 using a disc (not shown), and then the cassette 1 is opened.
The stimulable phosphor sheet 11 housed in the internal space 19 of 7 can be adsorbed, taken out from the housing 21, and placed on a transport system of a light beam scanning device such as a radiation image information reading device.

As illustrated in FIG. 4, the light beam scanning device used in the present invention basically includes a laser light source 39, an imaging lens 41, a polygon mirror 43, a light guide 45, and a photomultiplier 47. , a condensing mirror 49, and a sub-scanning conveyance system 51. In this case, the imaging lens 41 is arranged in front of the polygon mirror 43, which is a so-called post-objective configuration.
The imaging lens 41 used does not need to be an expensive scanning lens with fθ property used in a plane scanning system (
Commonly used inexpensive imaging lens (ftanθ lens)
That's fine.

The laser light source 39 is an excitation light source that emits a laser beam such as a gas laser or a semiconductor laser, that is, an excitation light beam.

The imaging lens 41 is provided on the optical path of the excitation light beam B emitted from the laser light source 39 and forms an image of this light beam on a predetermined approximately circular arc, that is, on the stimulable phosphor sheet 11 .

The polygon mirror 43 is provided on the optical path and deflects the excitation light beam B focused by the imaging lens 41 at a predetermined angle, so that the fluorescent light is transported while being held in a predetermined substantially arc shape by the sub-scanning transport system 51. This is an optical deflector that defines a substantially arc-shaped main scanning curve S larger than the width on the body sheet 11.

The light guide 45 is made of a photoconductive sheet, and has an entrance end surface 53 that extends along the main scanning line S at one end thereof, is disposed close to it, and is made of a curved surface that envelops a substantially arcuate curve that is conjugate with the main scanning curve S. The other end is wound in an annular shape to fit the light receiving surface 57 of the photomultiplier 47, and the light receiving surface 5
It has an exit surface 55 that is brought into close contact with 7. The condensing mirror 49 is irradiated with the excitation light beam B to produce a main scanning curve S.
Among the stimulated luminescent light generated along the direction, the stimulated luminescent light directed toward the condensing mirror 49 is directed to the incident end surface 53 of the light guide 45.
The light is reflected towards the target and increases the light collection efficiency. It is preferable that the reflective surface of the condensing mirror 49 is configured to have a substantially cylindrical shape.

The photomultiplier 47 photoelectrically converts the stimulated luminescence light into an electrical signal, and the obtained electrical signal is transmitted from the photomultiplier 47 to an image processing device 59 and subjected to image processing, and then displayed on a display device such as a CRT. 61 and stored in a recording medium 63 such as a video or CD, or reproduced as a visible image on a film 49 or the like. Note that when it is necessary to convert a curved image into a flat image and display it on the display device 61, the image processing device 59 performs the conversion according to a predetermined algorithm.

The sub-scanning conveyance system 51 for such a stimulable phosphor sheet 11 involves mixing magnetic particles into the support layer of the sheet, and suspending and moving the sheet using an electromagnet that generates a fluctuating magnetic field in the sub-scanning conveyance device. Alternatively, a stimulable phosphor sheet constituting a mover, a stator having electrodes that generate a driving force to move the phosphor sheet while holding it on a predetermined substantially cylindrical surface, and a drive power source. There are a method using an electrostatic actuator composed of the following, a method using a magnetostrictive actuator, a method using an ultrasonic actuator, etc.

By the way, this sub-scanning conveyance system 51 is not provided with suction means such as air suction as in the past, and the only part that moves in this sub-scanning conveyance system 51 is the part on which the stimulable phosphor sheet is placed. In some cases, only the stimulable phosphor sheet can be suspended and moved using air or magnetism, so the mechanism required for sub-scanning can be greatly simplified, and the sub-scanning transport system can be downsized. can.

The stimulable phosphor sheet of the present invention and the cassette containing the same are not limited to the illustrated example, and can be modified in various ways.

<Effects of the Invention> As described in detail above, according to the present invention, when this stimulable phosphor sheet is applied to an image reading device, post-objective optical scanning is enabled, and plane scanning is possible. There is no need for an expensive scanning lens having the fO property required for this, and an adsorption/holding means such as an image reading device can be omitted, and the sub-transport system can be made smaller and simpler.

Therefore, the entire image reading device can be made smaller and more compact, and furthermore, the cost can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective explanatory view of one embodiment of a stimulable phosphor sheet according to the present invention. FIG. 2 is a perspective explanatory view of one embodiment of a cassette for storing a stimulable phosphor sheet according to the present invention. 3 is a partially sectional side view of the cassette of the present invention shown in FIG. 2; FIG. FIG. 4 is a perspective view of an embodiment of the radiation image information reading device used in the present invention. FIG. 5 is a perspective explanatory view showing a conventional stimulable phosphor sheet. Explanation of symbols 11...Stormable phosphor sheet, 13...Surface of stimulable phosphor sheet, 15...Back surface of stimulable phosphor sheet, 17...Cassette, 19...Inner space, 21... Housing, 23... Lid body, 25... Hinge, 27... Lock mechanism, 29... Claw member, 31... Guide member, 33... Spring, 35... - Retaining part, 37... Hole, 39... Laser light source, 41... Imaging lens, 43... Polygon mirror 45... Light guide, 47... Photo multiplier, 49... Condensing mirror 51...Sub-scanning conveyance system, 53...Incidence end surface of light guide, 55...Emission surface of light guide, 57...Light receiving surface of photomultiplier, 5...
Image processing device, 61...Display device, 63...Recording medium, 65...Film patent applicant Fuji Photo Film Co., Ltd. Agent Patent attorney Minoru Watanabe F.I.G.
1

Claims (2)

[Claims] (1) A stimulable phosphor comprising a support and a phosphor layer provided thereon for accumulating and recording radiographic image information, and having a substantially cylindrical shape. sheet. (2) A cassette for storing the stimulable phosphor sheet according to claim 1, wherein the cassette contains the stimulable phosphor sheet and has a holding surface curved along the stimulable phosphor sheet. and a lid body which is attached to the housing so as to be openable and closable and is curved to match the curved holding surface.