JP7548032B2 - Radiation detector, radiation imaging device having radiation detector, support body used in radiation detector, and method for manufacturing support body - Google Patents

Description

The present invention relates to a radiation detector, a radiation imaging device having a radiation detector, a support used in the radiation detector, and a method for manufacturing the support.

There are various methods for medical and industrial use in which radiation (X-rays) are used to photograph the inside of a subject (e.g. the human body) for diagnosis. Traditionally, methods for obtaining images using film and computed radiographs (CR) using photostimulable phosphor plates have been used. In recent years, digital radiographs (DR), which receive the distribution of X-rays with a sensor and convert them into image data with a processing circuit, have become the mainstream form of radiation imaging equipment. These DRs use radiation detectors known as flat panel detectors (FPDs), and portable radiation imaging equipment has become more widely used in recent years for its convenience when taking images.

FPDs contain many built-in sensors (elements such as photodiodes) that detect X-rays irradiated onto a subject and output them as electrical signals. These sensors are fabricated, for example, on a glass or resin substrate and housed in a housing as a sensor panel that serves as a radiation detection unit. The sensor panel outputs the detected X-rays as an electrical signal. In addition, on the rear surface of the sensor panel (the surface opposite the surface irradiated with X-rays), various electronic components such as a circuit board with electronic devices (elements) for generating image data based on the output electrical signals and a battery are arranged.

FPDs may take X-rays while a subject such as a human body is placed on the housing, so they require a structure that protects the sensor panel, electronic components, circuit board, and elements on the circuit board from external forces such as the load and impact from the subject. In particular, in recent years, many thin FPDs that comply with JIS standards have been considered, and there is a demand for FPDs that are strong enough to protect the sensor panel, circuit board, etc. from external forces such as the load and impact from the subject.

In order to improve the strength of FPDs, the use of highly rigid supports such as metals as supports for supporting the sensor panel and electronic components has been considered. However, while using highly rigid supports such as metals can protect the sensor panel and other components from external forces such as the load and impact from the subject, the device becomes heavy and difficult to carry. Therefore, studies are being conducted to make the entire device lighter while maintaining the strength to protect it from external forces such as the load and impact from the subject.

For example, Patent Document 1 describes a radiographic imaging device having a sensor panel, electronic components arranged below the sensor panel, a support that supports the sensor panel and electronic components, and a housing for housing the sensor panel, the electronic components, and the support. Patent Document 1 claims that by making the support that supports the sensor panel and electronic components a porous member (e.g., a hard resin foam) having a large number of voids, it is possible to provide a radiographic imaging device that can reduce the weight while suppressing bending and local distortion of the sensor panel and the like.

JP 2019-196944 A

The inventors have found that, although the device can be made lighter by using a porous material for the support, as in Patent Document 1, the porous material in Patent Document 1 does not provide sufficient strength to protect the sensor panel and other components from external forces, such as the load from the subject. There is also a demand for lighter radiation detectors.

The object of the present invention is to provide a radiation detector that is lightweight and has sufficient strength against external forces such as the load of a subject. Another object of the present invention is to provide a support included in the radiation detector and a method for manufacturing the support.

In order to solve the above problem, a radiation detector according to one embodiment of the present invention is a radiation detector having a radiation detection unit that detects radiation and a support that supports the radiation detection unit, and the support is made of a bead-process foam.

To solve the above problem, a radiation imaging device according to one embodiment of the present invention has a radiation irradiation device and the radiation detector arranged at a position to receive radiation irradiated from the radiation irradiation device.

To solve the above problem, the support according to one embodiment of the present invention is made of a bead-processed foam material that is used in the radiation detector.

In order to solve the above problems, a method for manufacturing a support according to one embodiment of the present invention includes a step of introducing resin particles containing a foaming agent into a molding vessel, and a step of foaming the resin particles by heating inside the molding vessel.

The present invention can provide a radiation detector that is lightweight and has sufficient strength against external forces such as the load of a subject. The present invention can also provide a radiation imaging device that has the above-mentioned radiation detector. The present invention can also provide a support used in the radiation detector and a method for manufacturing the support.

FIG. 1 is a perspective view that shows a schematic configuration of a radiation imaging apparatus having a radiation detector according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the radiation detector according to the first embodiment. 3A to 3F are schematic diagrams illustrating a part of the manufacturing process of the bead method foam according to the first embodiment. FIG. 4 is a cross-sectional view showing a molding vessel used in a process for producing a foam by the beads method according to one embodiment of the present invention. FIG. 5 is a cross-sectional view of a radiation detector according to the second embodiment. 6A to 6G are schematic diagrams illustrating a part of the process for producing a foam produced by the bead method according to the second embodiment. FIG. 7 is a cross-sectional view of a radiation detector according to the third embodiment. 8A to 8G are schematic diagrams illustrating a part of the manufacturing process of a bead method foam according to the third embodiment.

The following describes in detail an embodiment of the present invention with reference to the drawings. Note that the present invention is not limited to the following embodiment.

[First embodiment]
1. Radiation Imaging Apparatus Fig. 1 is a diagram that illustrates a radiation imaging apparatus 10 having a radiation detector 100 according to the present embodiment.

The radiation imaging device 10 according to this embodiment is a device that irradiates a patient (hereinafter referred to as subject) S with X-rays (radiation) in a hospital to capture an X-ray image (radiation image). The radiation imaging device 10 includes a radiation detector 100 that detects the X-rays (radiation) irradiated to the subject S and outputs the X-rays (radiation) as an electrical signal, and a radiation irradiation device 20 for outputting the X-rays (radiation). The radiation imaging device 10 also includes a CPU 30 that receives the electrical signal output from the radiation detector 100 and performs imaging and display, and a cradle device 40 as a peripheral device that charges the battery in the radiation detector 100, etc.

The radiation irradiation device 20 has an X-ray irradiation unit 50 equipped with a known X-ray tube (vacuum tube) not shown and used in close proximity to the subject S. The CPU 30 is a computer that mainly controls radiographic imaging, displays X-ray images acquired from the radiation detector 100, and issues instructions regarding image processing content related to X-ray image data. The CPU 30 has a processor, an operation input unit such as a mouse or keyboard, and a display unit for displaying images on a display unit 60 such as a liquid crystal display, and performs the above-mentioned control, display, instructions, etc. through various screens such as a menu screen displayed on the display unit 60.

The general operation of the radiation imaging device 10 will be explained using an example in which X-ray photography of a subject S is performed.

Through an operation screen (not shown) for performing X-ray photography displayed on the display unit 60, parameters such as the intensity of X-rays output from the X-ray irradiation unit 50 are input to the CPU 30 by inputting operations such as with a mouse. After completing the input operations, by selecting the photography button on the display screen of the display unit 60, the radiation irradiation device 20 is operated and X-rays are output from the X-ray irradiation unit 50 according to the set parameters.

The output X-rays pass through the affected area of the subject S and are irradiated onto the radiation detection section 110 of the radiation detector 100. The radiation detector 100 detects the intensity (distribution of intensity) of the X-rays that have passed through the affected area of the subject S using the radiation detection section 110, converts the detected X-rays into electrical signals, digitizes the converted electrical signals, and transfers them to the CPU 30. The CPU 30 processes the received data as appropriate to create an image, and displays it on the display section 60 as an X-ray image.

2. Configuration of the Radiation Detector Fig. 2 is a cross-sectional view of the radiation detector 100 according to the first embodiment. As shown in Fig. 2, the radiation detector 100 has a radiation detection unit 110 that converts radiation into an image signal, and a support body 120 that supports the radiation detection unit 110. The radiation detection unit 110 and the support body 120 are housed inside a housing 130. In addition, electronic components such as an electric board 140 and a battery 150 may be housed inside the housing 130.

2-1. Radiation Detection Unit The radiation detection unit 110 is a sensor panel having a plurality of sensors that detect X-rays (radiation) irradiated to a subject (e.g., a human body) and output the X-rays as an electrical signal. As shown in Fig. 2, the radiation detection unit 110 has radiation detection elements 111 and a substrate 112 that supports the radiation detection elements 111. The radiation detection elements 111 are arranged in a two-dimensional matrix of n x m on the substrate 112.

The substrate 112 may be a glass substrate or a flexible substrate. In this embodiment, a flexible substrate is preferable. A flexible substrate has a property that the substrate can bend even when a predetermined force is applied to the substrate, and therefore damage to the substrate can be suppressed. In addition, a flexible substrate is generally lighter than a glass substrate, so that the radiation detection unit 110 can be made lighter than a conventional one. In addition, the support 120 described later is a bead-process foam, and is therefore lighter than a conventional foam (a foam that is not a bead-process foam), so that the radiation detector 100 can be made even lighter. Therefore, according to the radiation detector 100, it is possible to reduce the weight while maintaining the resistance of the substrate to damage when subjected to an external force such as a load from a subject.

Examples of flexible substrates include polyester resin films such as polyethylene terephthalate, polyethylene naphthalate, and modified polyester, polyethylene resin films, polypropylene resin films, polystyrene resin films, polyolefin resin films such as cyclic olefin resins, vinyl resin films such as polyvinyl chloride and polyvinylidene chloride, polyether ether ketone resin films, polysulfone resin films, polyethersulfone resin films, polycarbonate resin films, polyamide resin films, polyimide resin films, acrylic resin films, and triacetyl cellulose resin films.

2-2. Support The support 120 is a member that supports the radiation detection unit 110. The shape of the support 120 is not particularly limited, but it is preferable that the surface of the support 120 that comes into contact with the radiation detection unit 110 is flat and that the support 120 can support the lower surface (rear surface side) of the radiation detection unit 110 without gaps in the thickness direction and the planar direction. In addition, as shown in FIG. 2, the support 120 is preferably shaped to have a space for accommodating the electric board 140 and the battery 150 in the housing 130. Note that in this embodiment, the shape of the support 120 is not limited to the shape shown in FIG. 2 as long as it has a space for accommodating the electric board 140 and the battery 150. In addition, the support 120 may be shaped to fill the space in the housing 130 where devices such as the radiation detection unit 110, the electric board 140, and the battery 150 are not arranged without gaps, eliminating the space where nothing is arranged.

The support 120 according to this embodiment is made of a bead-method foam. A bead-method foam is made by foaming expandable resin particles, which are resin particles impregnated with a foaming agent. By adjusting the expansion ratio, the bead-method foam can be made lighter while maintaining a density sufficient for strength against external forces such as the load from the subject. In this embodiment, a bead-method foam refers to a foam in which resin particles impregnated with a foaming agent are heated with steam to foam the foaming agent, expanding the volume of the resin particles several to several tens of times.

In this embodiment, the resin particles are not particularly limited as long as they can be impregnated with a foaming agent, but are preferably thermoplastic resins.

Examples of thermoplastic resins include polyolefin resins such as polyethylene, polypropylene, and EVA (ethylene-vinyl acetate copolymer), polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, ABS (acrylonitrile-butadiene-styrene) resin, AS (acrylonitrile-styrene) resin, polystyrene resin, methacrylic resin, polyamide resin, polycarbonate resin, polyphenylene ether resin, polyimide resin, polyacetal resin, polyester resin, acrylic resin, cellulose resin, polyurethane resin, styrene-based, polyvinyl chloride-based, polyurethane-based, polyester-based, polyamide-based, 1,2-polybutadiene-based, and fluororubber-based thermoplastic elastomers, polyamide-based, polyacetal-based, polyester-based, and fluororubber-based thermoplastic engineering plastics, powdered rubber, etc. These may be used alone or in combination of two or more types. Modified and crosslinked resins may also be used within the scope of the present invention. Of the above thermoplastic resins, polyethylene, polystyrene, polypropylene, and polyphenylene ether resins are preferred.

The foaming agent impregnated into the resin particles may be a known volatile foaming agent or an inorganic foaming agent. Examples of volatile foaming agents include aliphatic hydrocarbons such as propane, butane, and pentane, aromatic hydrocarbons, alicyclic hydrocarbons, and aliphatic alcohols. Examples of inorganic foaming agents include carbon dioxide gas, nitrogen gas, air, and inert gases (e.g., helium gas and argon gas).

In this embodiment, resin particles (including commercially available products) that have already been impregnated with a foaming agent may be used.

The bead-method foam according to the present embodiment preferably contains an antistatic agent dispersed therein or has its surface coated with an antistatic agent. The antistatic agent dispersed in the bead-method foam means that the antistatic agent mixed in the production of the bead-method foam or contained on the surface or inside of the resin particles is present in the bead-method foam after foaming. The antistatic agent may be uniformly dispersed in the bead-method foam, or may be localized in a part of the interior of the bead-method foam. The surface of the bead-method foam coated with an antistatic agent means that all or a part of the surface of the bead-method foam is coated with a coating film containing an antistatic agent. The coating film may cover the entire surface of the bead-method foam, but may cover only a part of the surface of the bead-method foam, such as a part in contact with the radiation detection unit 110, or a part that may generate electromagnetic waves, such as the electric board 140 or the battery 150, or both. In the present embodiment, it is more preferable that the bead-method foam contains an antistatic agent dispersed therein.

An antistatic agent is an agent that inhibits the accumulation of static electricity by making the insulating material more conductive. There are no particular limitations on the type of antistatic agent, and any known agent can be used. Examples of antistatic agents include cationic surfactants, anionic surfactants, and nonionic surfactants. By using the above surfactants as antistatic agents, moisture in the air can be adsorbed onto the surface of the insulating material, lowering the electrical resistance, thereby inhibiting the accumulation of static electricity in the bead method foam.

Examples of cationic surfactants include quaternary ammonium salts such as alkyltrimethylammonium salts.

Examples of anionic surfactants include sulfate ester salts such as alkali metal salts of higher fatty acids, sulfonate salts such as alkylbenzene sulfonate salts, alkyl sulfonate salts, and paraffin sulfonate salts, and phosphate ester salts such as higher alcohol phosphate ester salts.

Examples of nonionic surfactants include polyethylene glycol-type nonionic surfactants such as higher alcohol ethylene oxide adducts, fatty acid ethylene oxide adducts, higher alkylamine ethylene oxide adducts, and polypropylene glycol ethylene oxide adducts, as well as polyhydric alcohol-type nonionic surfactants such as polyethylene oxide, fatty acid esters of glycerin, fatty acid esters of pentaerythritol, fatty acid esters of sorbitol or sorbitan, alkyl ethers of polyhydric alcohols, and fatty amides of alkanolamines.

Bead-method foams are usually prone to static electricity, but antistatic treatment can prevent the support from becoming charged, and can suppress malfunctions of sensor panels and electrical circuits caused by a charged support. Whether or not a bead-method foam has been antistatically treated can be determined, for example, by measuring or detecting with a surface electrometer.

The bead method foam may also contain surface treatment agents such as anti-binding agents (anti-coalescence agents) and spreading agents, if necessary. Anti-binding agents suppress the coalescence of pre-expanded resin particles in the pre-expanding step (described below) when manufacturing the bead method foam. Coalescence here refers to the coalescence of multiple pre-expanded resin particles into one body. Examples of anti-binding agents include talc, calcium carbonate, and aluminum hydroxide. The amount of anti-binding agent added is preferably 0.01 to 1.0 part by mass per 100 parts by mass of the resin particles. Examples of spreading agents include polybutene, polyethylene glycol, and silicone oil.

The bead-method foam is lightweight and has high strength. Therefore, by forming the support from the bead-method foam, the support can be made lighter while maintaining sufficient strength against external forces such as the load from the subject. In general, the mass (density) of the bead-method foam becomes lighter as the expansion ratio is increased. In addition, by not increasing the expansion ratio too much, the decrease in strength can be suppressed and the desired strength can be maintained. From the viewpoint of achieving both, the support according to the present embodiment is preferably made of a bead-method foam having an expansion ratio of 5 to 30 times, and more preferably made of a bead-method foam having an expansion ratio of 5 to 10 times. If the expansion ratio is 5 times or more, the weight of the bead-method foam can be sufficiently reduced, and the bead-method foam can be easily manufactured. In addition, if the expansion ratio is 30 times or less, even if the thickness of the thinnest part of the bead-method foam in the direction of receiving radiation is within the range described below, 2 to 3 resin particles will be present in the thinnest part in terms of resin particles before foaming. Therefore, even after foaming, a sufficient amount of resin remains in the thinnest part, so that the strength of the bead method foam is sufficient to prevent compression deformation, bending deformation, etc., even when subjected to a load from a subject. For example, when used in a radiation detector that is placed under a subject lying on a bed to capture a radiation image, the upper limit of the foaming ratio may be about 30 times, and when used in a radiation detector that captures an image of the foot of a subject standing on the radiation detector with one foot, the upper limit of the foaming ratio may be about 10 times to further increase the strength of the support. The foaming ratio can be calculated by dividing the density of the resin particles, which are the material of the bead method foam, by the density of the bead method foam after foaming.

From the viewpoint of achieving both weight reduction and high strength of the support, the density of the bead method foam is preferably 33 kg/ ^m3 or more and 200 kg/ ^m3 or less, and more preferably 100 kg/ ^m3 or more and 200 kg/ ^m3 or less. By setting the density of the bead method foam to 33 kg/ ^m3 or more, it is possible to maintain a density that provides sufficient strength against external forces such as the load from the subject. Furthermore, by setting the density to 100 kg/m3 or ^less , it is possible to reduce the weight of the bead method foam.

The bead-method foam in this embodiment may be made by foaming unfoamed resin particles (impregnated with a foaming agent), or may be made by foaming pre-foamed resin particles (described below). The fact that the support is made of a bead-method foam can be determined by visual inspection because the bead-method foam has a cellular structure.

2, the thickness _t1 of the thickest part in the direction of receiving radiation is preferably 8 mm or more and 12 mm or less, and more preferably 8 mm or more and 10 mm or less. By making the thickness _t1 of the thickest part of the support 120 8 mm or more, the radiation detection unit 110 and the support can be disposed in close contact with each other within the housing 130. By making the thickness _t1 of the thickest part of the support 120 12 mm or less, the radiation detector 100 can be adjusted to a size conforming to the JIS standard while accommodating the radiation detection unit 110, the electric board 140, the battery 150, and the like within the radiation detector 100.

In addition, the thickness t ₂ of the thinnest part of the support (beads method foam) 120 in the direction of receiving radiation is preferably 1.5 mm or more and 5.0 mm or less, and more preferably 2.0 mm or more and 4.1 mm or less. When the thickness t ₂ of the thinnest part of the bead method foam is 1.5 mm or more, 2 to 3 resin particles before foaming can be present in the thickness t ₂ of the thinnest part, so that sufficient bending strength can be obtained. Usually, the thickness t ₂ of the thinnest part is the thickness of the part where the battery 150 and other devices are disposed on the opposite side of the radiation detection unit 110 of the support 120 inside the radiation detector 100. This allows the support to bend even when subjected to an external force such as a load from the subject, so that it is less likely to break. In addition, when the thickness is 5.0 mm or less, not only the support but also an electric board, a battery with a large capacity, and the like can be appropriately accommodated in the radiation detector 100 having a thickness as specified by the JIS standard. The reason for setting the thickness t ₂ in the above range will be explained below.

For example, if resin particles having a diameter of 0.5 mm before foaming are expanded 10 times to increase the strength of the support, and two resin particles having a diameter of 1.1 mm (0.5 mm × cube root of 10) are present in the thickness direction of the thinnest part of the support by hexagonal close packing, the thickness _t2 will be 2.0 mm ((√6/3 + 1) × 1.1 mm). Also, if resin particles having a diameter of 0.5 mm before foaming are expanded 30 times to increase the strength of the support, and three resin particles having a diameter of 1.6 mm (0.5 mm × cube root of 30) are present in the thickness direction of the thinnest part of the support by close packing, the thickness _t2 will be 4.1 mm ((√6/3 + 1) × 1.6 mm). Note that, since a dimensional variation of about 25% occurs during molding of the support, the preferred range is 1.5 mm to 5.0 mm, which is a thickness taking into account the variation.

2-3. Housing As shown in Fig. 2, the housing 130 accommodates electronic components such as the radiation detection unit 110, the electric board 140, and the battery 150 in addition to the support 120. The housing 130 also has a main body 131 and a bottom plate 132. In this embodiment, as shown in Fig. 2, the box body 131 is formed so that its cross section is substantially U-shaped, but is not limited to this. The top plate 133 and the side plates 134, 135 may be separate members, and the side plate 134 may be fixed to one side of the top plate 133 by abutting against it, and the side plate 135 may be fixed to the other side by abutting against it.

The material of the housing 130 is preferably carbon fiber reinforced plastics (CFRP), glass fiber reinforced plastics (GFRP), carbon fiber reinforced thermoplastics (CFRTP), light metal, or an alloy containing light metal. By using the carbon fiber reinforced resin or the like as the material of the housing 130, the housing 130 can be made lighter while maintaining its rigidity. In particular, carbon fiber reinforced resin has a high radiation transmittance, and can allow radiation that has passed through the subject to reach the radiation detection unit 110 without attenuation on the way, thereby improving the image quality of the radiation image. The box body 131 and the lid body 132 may be made of the same material or different materials.

2-4. Electrical Board The electrical board 140 is connected to the radiation detection unit 110, and performs A/D conversion (digitization of the converted electrical signal) of electric charges (intensity state of the irradiated X-rays) due to X-rays (radiation) detected by each sensor (radiation detection element) in the sensor panel, and supplies the converted digital data to the main circuit board (not shown). The main circuit board integrates the digital data to generate data of an X-ray image of the entire affected area of the subject (photographed image data), and temporarily stores the generated photographed image data in the radiation detector 100. Furthermore, the main circuit board outputs the generated photographed image data to an external device such as the above-mentioned CPU 30 (see FIG. 1) through an input/output interface (not shown) provided on the side of the housing 130.

The battery 150 is, for example, a battery that can be repeatedly charged and discharged, such as a lithium ion battery, and is charged by power supplied from the cradle device 40 via a charging connector (not shown) provided on the side of the housing 130. The battery 150 also supplies power to electronic devices inside the radiation detector 100, such as the radiation detection unit 110.

Next, we will explain the manufacturing method of the support according to the first embodiment.

3. Method for manufacturing a support The method for manufacturing a support according to the first embodiment includes a step of putting resin particles containing a foaming agent into a molding vessel, and a step of foaming the resin particles by heating inside the molding vessel. The method for manufacturing a support according to the first embodiment preferably includes a step of smoothing the surface of the put-in resin particles after the step of putting the resin particles into the molding vessel and before the step of foaming. The method for manufacturing a support according to the first embodiment may include a step of manufacturing resin particles containing a foaming agent, and a step of pre-foaming the resin particles containing a foaming agent. Each step will be described below.

3-1. Step of Producing Resin Particles Containing a Foaming Agent The step of producing resin particles containing a foaming agent is a step of producing expandable resin particles by impregnating resin particles with a foaming agent.

In this embodiment, it is preferable that the resin particles are made of the thermoplastic resin described above.

The foaming agent impregnated into the resin particles can be the volatile foaming agent or inorganic foaming agent described above.

In addition, in the first embodiment, resin particles (including commercially available products) that are pre-impregnated with a foaming agent may be used.

3-2. Step of pre-expanding resin particles The step of pre-expanding resin particles is a step of placing resin particles containing a foaming agent in a pre-expanding tank and heating to perform pre-expansion. Pre-expansion of resin particles can be performed by a known method. Examples of pre-expansion methods include a method of heating and expanding expandable particles with hot air, a heat medium such as oil, steam (water vapor), etc. For stable production, a method of heating with steam is preferred. It is preferable to use a sealed pressure-resistant foaming container for the foaming machine during pre-expansion. Commercially available pre-expanded resin particles can be used.

In addition, in this embodiment, if the expansion ratio of the resulting bead method foam can be 5 times or more and 30 times or less, a bead method foam obtained by further expanding resin particles (including commercially available products) that have been pre-expanded in advance may be used.

3-3. Step of putting pre-expanded resin particles into a molding container The step of putting pre-expanded resin particles into a molding container is a step of putting pre-expanded resin particles into a molding container. By putting resin particles into a molding container to form a support, a support having a fine and complicated structure can be formed with higher accuracy than by processing a molded bead method foam (e.g., rectangular) into the shape of a desired support. In particular, when making a radiation detector thinner, it is required that the support also has a fine and complicated shape. In order to manufacture such a molded body with a fine and complicated shape, a method of molding a molded body with the shape is desirable. Note that, although a certain degree of dimensional variation occurs during molding, the dimensional variation due to molding is about 25% above or below the design value, and at this level, there is no problem when the support is accommodated in the radiation detector, and the dimensional accuracy is better than that of post-processing the molded body into the shape of the support.

Figures 3A to 3D are schematic diagrams illustrating the process of introducing resin particles 240 into molding container 200 in embodiment 1. Figure 3A is a cross-sectional view of molding container 200 used in embodiment 1. As shown in Figure 3A, molding container 200 has at least closing section 210, resin particle receiving section 220, and introduction port 230. Note that Figures 3C and 3D will be explained in the process of smoothing the resin particles described below.

The size and shape of the molding container 200 shown in Fig. 3A are not particularly limited. In this embodiment, the molding container 200 has a size and shape in which the thickness _t1 of the thickest part of the bead-method foam in the direction of receiving radiation is preferably 8 mm or more and 12 mm or less, and more preferably 8 mm or more and 10 mm or less. By making the thickness _t1 of the thickest part of the bead-method foam 8 mm or more, the radiation detection unit 110 and the bead-method foam can be arranged in close contact with each other in the housing 130. In addition, by making it 12 mm or less, the radiation detector 100 can be adjusted to a size conforming to the JIS standard while accommodating the radiation detection unit 110, the electric board 140, the battery 150, and the like inside the radiation detector 100.

Moreover, the molding container 200 preferably has a size and shape such that the thickness _t2 of the thinnest part of the molded bead-method foam in the direction of receiving radiation is 1.5 mm or more and 5.0 mm or less, and more preferably has a size and shape such that the thickness _t2 of the thinnest part of the molded bead-method foam in the direction of receiving radiation is 2.0 mm or more and 4.1 mm or less. By using a molding container 200 having a thickness t2 of 1.5 mm or more, the molded bead-method foam can have 2 to 3 resin particles before foaming in the thickness _t2 of the thinnest part, so that the molded foam can obtain sufficient bending strength. As a result, even if an external force such as a load from the subject is applied, the support can bend, so that it is less likely to break. By putting the molded container 200 having a thickness _t2 of 5.0 mm or less at the thinnest part, not only the support but also an electric board, a large-capacity battery, etc. can be appropriately accommodated in the radiation detector 100 having a thickness as specified by the JIS standard.

The method of feeding the resin particles 240 into the molding container 200 is not particularly limited. The resin particles 240 may be fed into the resin particle receiving section 220 from the inlet 230 of the molding container 200 under normal pressure, or the resin particles 240 may be fed into the resin particle receiving section 220 from the inlet 230 of the molding container 200 under pressure, or the resin particles 240 may be fed into the resin particle receiving section 220 from the inlet 230 while exhausting air from a part of the molding container 200 to reduce the pressure. The resin particles may also be filled into the molding container 200 using a funnel-shaped auxiliary tool, or the resin particles may be filled into the molding container 200 while vibrating it so that the resin particles are filled evenly.

In this embodiment, the resin particles 240 are preferably introduced into the molding container 200 under normal pressure. In order to fill the resin particles while discharging or introducing air, it is necessary to have a flow path inside the molding container that is wide enough for the air and resin particles to pass through. However, in order to arrange other components without gaps inside the limited thickness of the radiation detector, the shape of the support becomes thin and more complex. Therefore, the shape of the molding container also becomes thinner and more complex, and it is possible that the above-mentioned flow path of sufficient width cannot be secured. If an attempt is made to fill the resin particles by discharging or introducing air, the air may not be able to enter the entire inside of the molding container, or the resin particles may get clogged in the middle of the flow path. In contrast, by introducing the resin particles under normal pressure and filling them relatively slowly, the resin particles can be densely filled without leaving any gaps inside the molding container 200.

Figure 3B is a cross-sectional view showing the state in which the resin particles 240 are poured so as to overflow from the inlet 230 of the molding container 200. As shown in Figure 3B, by pouring an amount of resin particles 240 that overflows from the inlet 230 of the molding container 200 and removing the excess particles in a later process, it is possible to prevent the formation of spaces not filled with the resin particles 240 near the inlet 230, etc., and to fill the inside of the molding container 200 with the resin particles 240 without any gaps.

In addition, the resin particles 240 containing a foaming agent that are added to the molding container 200 may be resin particles in an unfoamed state.

In addition, it is preferable that the resin particles 240 have an antistatic treatment applied to the particle surface or are mixed with an antistatic agent.

The antistatic agent may be any of the antistatic agents described above.

By carrying out the antistatic treatment, it is possible to prevent the resin particles from scattering outside the molding container due to static electricity when filling the molding container, or from adhering to unwanted objects. Note that the resin particles 240 may be resin particles (including commercially available products) that have already been subjected to an antistatic treatment.

The resin particles 240 may also be added with a surface treatment agent such as a binding inhibitor (anti-coalescence agent) or a spreading agent, if necessary. The binding inhibitor suppresses the coalescence of the pre-expanded resin particles in the pre-expanding step (described below). Coalescence here refers to the coalescence of multiple pre-expanded resin particles into one body. Examples of binding inhibitors include talc, calcium carbonate, and aluminum hydroxide. The amount of binding inhibitor added is preferably 0.01 to 1.0 part by mass per 100 parts by mass of the resin particles. Examples of spreading agents include polybutene, polyethylene glycol, and silicone oil.

In this embodiment, the molding vessel for feeding the resin particles containing the foaming agent is not limited to the horizontal molding vessel 200 shown in FIG. 3A. The molding vessel for feeding the resin particles may be, for example, a vertical molding vessel 300 (having at least a blocking portion 310, a resin particle receiving portion 320, and a feeding port 330) as shown in FIG. 4.

When resin particles are poured into the molding container 300, it is preferable that the resin particles are poured so that they overflow from the inlet 330 of the molding container 300, as described above.

3-4. Step of smoothing the resin particles Fig. 3C is a cross-sectional view showing the step of smoothing the resin particles, and Fig. 3D is a cross-sectional view showing the state of the resin particles after smoothing. The step of smoothing the surfaces of the resin particles is performed after the step of putting the resin particles 240 into the molding container 200 and before the step of foaming.

As shown in FIG. 3C, an example of a method for smoothing the surface of the resin particles 240 introduced into the molding container 200 includes a method using a squeegee (spatula for leveling) 250. By removing the resin particles 240 overflowing from the inlet 230 of the molding container 200 and smoothing the surface of the resin particles 240 at the inlet 230, the formation of spaces not filled with the resin particles 240 can be prevented near the inlet 230, and the resin particles 240 can be filled without gaps inside the molding container 200, so that a bead method foam (support) with uniform strength against external forces can be obtained. In addition, since there is no need to finely adjust the amount of resin particles introduced so that the amount is neither too much nor too little, the previous process can be carried out more easily.

3-5. Step of Heating and Expanding Resin Particles Inside the Forming Container In the step of heating and expanding resin particles inside the forming container, as shown in FIG. 3E, after closing inlet 230 of forming container 200 with closing part 210, the resin particles are expanded inside the forming container to a predetermined expansion ratio.

In the process of expanding the resin particles, for example, the molding container 200 is placed inside an oven and heated at 110 to 120°C for 1 to 2 minutes to expand the resin particles 240 to an expansion ratio of 5 to 30 times, and more preferably to an expansion ratio of 5 to 10 times. If the expansion ratio of the bead method foam is 5 times or more, the density of the bead method foam is small, so that the support 120 made of the bead method foam can be made lighter. If the expansion ratio of the bead method foam is 30 times or less, the density of the bead method foam can be maintained to have sufficient strength against external forces such as loads applied when measuring a subject.

The density of the bead method foam is preferably 33 kg/ ^m3 or more and 200 kg/ ^m3 or less, and more preferably 100 kg/ ^m3 or more and 200 kg/ ^m3 or less. By making the density of the bead method foam 33 kg/ ^m3 or more, it is possible to maintain a density sufficient for providing strength against external forces such as the load from the subject. Furthermore, by making the density 200 kg/ ^m3 or less, it is possible to reduce the weight of the bead method foam.

In this embodiment, the process may include a step of subjecting the bead-method foam to an antistatic treatment after the step of foaming the resin particles. The antistatic agent can be applied to the surface of the bead-method foam by a known method, such as a method of applying a coating liquid containing an antistatic agent and drying it. Although bead-method foams are usually prone to charging, this configuration can prevent charging of the foamed molded body as a support, and suppresses effects on the sensor panel and electrical circuits. Whether or not the bead-method foam has been subjected to an antistatic treatment can be determined, for example, by measuring or detecting with a surface potential meter.

In this way, a support 120 made of bead-processed foam can be obtained, as shown in FIG. 3F.

(effect)
By using a support made of a bead-processed foam as a material, it is possible to reduce the weight of the radiation detector and maintain the density of the bead-processed foam to provide sufficient strength against external forces such as the load applied when measuring a subject. This makes it possible to provide a radiation detector that is lightweight and has sufficient strength against external forces. Furthermore, the above manufacturing method makes it possible to accurately and efficiently manufacture supports having fine and complex shapes, thereby increasing the productivity of supports.

[Embodiment 2]
5 is a cross-sectional view of a radiation detector 400 according to embodiment 2. The radiation detector 400 differs from embodiment 1 in that the support 410 has a shielding material 420 for blocking electromagnetic waves. Therefore, the same components as those in the radiation detector 100 according to embodiment 1 are denoted by the same reference numerals and description thereof will be omitted.

As shown in FIG. 5, the radiation detector 400 has a radiation detection unit 110 that converts radiation into an image signal, and a support 410 that supports the radiation detection unit 110. The support 410 has a shielding material 420 for blocking electromagnetic waves. The radiation detection unit 110 and the support 410 are housed inside a housing 130. In addition, electronic components such as an electric board 140 and a battery 150 may be housed inside the housing 130.

5, the support 410 may be integrally formed with the shielding material 420, or may be disposed between the support 410 and the radiation detection unit 110. The support 410 having the shielding material 420 can improve the strength of the support 410. In addition, the support 410 having the shielding material can prevent noise generated in the electric board from passing through the support and adversely affecting the sensor panel. In this embodiment, "integrally formed" means that the shielding material is joined to the support (beads method foam) without using adhesive or mechanical joining. In this embodiment, as described later, the resin particles 240 in contact with the shielding material 420 are foamed, so that the shielding material 420 and the support 410 can be integrally formed.

The shielding material 420 is not particularly limited as long as it can shield electromagnetic waves generated from the electric board 140 and the like. Examples of the shielding material 420 include metal foils such as copper and aluminum, metal meshes such as aluminum and copper, resin films having metal thin films, and resin films having ITO films. Among the above shielding materials, metal foils with low resistance are preferred from the viewpoint of further improving shielding performance. From the viewpoint of weight reduction, metal meshes and films having metal thin films are preferred, and low-density aluminum is preferably used as the material in this case. By using a metal mesh, the beads are fused and fixed between the meshes, increasing the strength. In addition, the resin film is not particularly limited as long as it is a film of a material with a relatively high glass transition point (for example, a PET film), but from the viewpoint of fusion and improving the strength of the support, it is preferable that the resin film is the same type as the bead method foam. In addition, when the shielding material is a resin film having a metal thin film, even if the resin film is the same resin as the resin particles (bead method foam), the part corresponding to the resin film and the part corresponding to the resin particles can be distinguished by observing the cross section of the bead method foam, for example, with a cross-sectional microscope.

When a metal foil is used as the shielding material 420, the thickness of the shielding material 420 is preferably 20 μm or more and 100 μm or less. When a metal mesh is used, the wire diameter of the shielding material 420 can be about 0.15 mm. When a metal foil or a film having a metal thin film, or a resin film having an ITO film is used, the thickness of the shielding material 420 is preferably 25 μm or more and 125 μm or less. By setting the thickness and wire diameter of the shielding material 420 within the above range, the electromagnetic wave shielding effect between the radiation detection unit 110 and the electric board 140 can be improved. When a film having a metal thin film and the same resin as the bead method foam is used as the shielding material 420, the film can be fused during the formation of the support to improve the strength of the support.

2. Method for manufacturing a support The method for manufacturing a support according to the second embodiment includes a step of impregnating resin particles with a foaming agent to manufacture resin particles containing a foaming agent, a step of putting the resin particles containing a foaming agent into a molding vessel, and a step of heating and foaming the resin particles inside the molding vessel. The method for manufacturing a support according to the second embodiment preferably includes a step of smoothing the surface of the put-in resin particles after the step of putting the resin particles into the molding vessel and before the step of foaming. In addition, the method for manufacturing a support according to the second embodiment may include a step of manufacturing resin particles containing a foaming agent and a step of pre-foaming the resin particles containing a foaming agent, as in the first embodiment. Note that the same steps as those in the method for manufacturing a support according to the first embodiment will not be described.

2-1. Step of manufacturing resin particles containing a foaming agent The step of manufacturing resin particles containing a foaming agent is a step of impregnating resin particles with a foaming agent to manufacture expandable particles. The above step can be performed in the same manner as in the first embodiment.

2-2. Step of pre-expanding resin particles This is a step of placing resin particles containing a foaming agent in a pre-expanding tank and heating them to pre-expand. This step can be performed in the same manner as in the first embodiment.

2-3. Step of Feeding Pre-Expanded Resin Particles into a Molding Vessel The step of feeding pre-expanded resin particles into a molding vessel is a step of feeding pre-expanded resin particles into a molding vessel.

Figures 6A to 6E are schematic diagrams illustrating the process of introducing resin particles 240 into a molding vessel 500. Figure 6A is a cross-sectional view of a molding vessel 500 used in embodiment 2. As shown in Figure 6A, the molding vessel 500 has at least a blocking portion 210, a resin particle receiving portion 220, and an introduction port 230. Figures 6C to 6E will be described in the process of smoothing the resin particles described below.

Figure 6B is a cross-sectional view showing the state in which the resin particles 240 and the shielding material 420 are arranged in the resin receiving section 520. The method of introducing the resin particles 240 into the molding container 500 can be performed in the same manner as in embodiment 1.

As shown in FIG. 6B, it is preferable to pour a certain amount of resin particles 240 into the resin receiving section 520 and place the shielding material 420 on the surface of the poured resin particles 240. In this embodiment, the shielding material 420 may be placed in the resin receiving section 520 before pouring the resin particles 240, or may be placed after pouring the amount of resin particles 240 to be poured into the resin receiving section 520.

Then, after placing the shielding material 420 on the surface of the resin particles 240, further resin particles 240 are poured into the resin receiving section 520 so as to cover the shielding material 240 (see FIG. 6C).

At this time, the resin particles 240 containing the foaming agent that are put into the molding container 500 can be the resin particles that can be used in the first embodiment. In addition, it is preferable that the particle surface of the resin particles 240 is subjected to an antistatic treatment or that the resin particles 240 are mixed with an antistatic agent. The same antistatic agent as in the first embodiment can be used as the antistatic agent.

6C to 6E are cross-sectional views showing the step of smoothing the surface of resin particle 240. The step of smoothing the surface of resin particle 240 is carried out after the step of putting resin particle 240 into molding container 500 and before the step of foaming. The above step can be carried out in the same manner as in embodiment 1.

2-5. Step of Heating and Expanding Resin Particles Inside the Forming Container The step of heating and expanding resin particles inside the forming container is a step of expanding the resin particles to a predetermined expansion ratio after blocking inlet 530 of forming container 500 with blocking part 510 as shown in Fig. 6F with shielding material 420 placed in forming container 500, and can be performed in the same manner as in embodiment 1. In this step, it is preferable to expand the resin particles to an expansion ratio of 5 to 30 times, and more preferably to expand the resin particles to an expansion ratio of 5 to 10 times.

In this way, as shown in FIG. 6G, a support 410 made of a bead-processed foam having a shielding material 420 can be obtained. Note that in this embodiment, the support is formed integrally with the shielding material 420, but this is not limiting. The shielding material 420 may be disposed between the support 410 and the sensor panel 140.

In this embodiment, a step of subjecting the bead method foam to an antistatic treatment may be included after the step of foaming the resin particles. The application of an antistatic agent to the surface of the bead method foam can be performed in the same manner as in embodiment 1.

(effect)
By using a support made of a bead-processed foam having a shielding material such as a metal foil, a support having an electromagnetic shielding effect can be obtained. In addition, by using a film having a thin metal film (the film is made of the same resin as the bead-processed foam) as the shielding material, the film can be fused during the formation of the support, thereby improving the strength of the support. This makes it possible to suppress the adverse effects on the sensor panel of noise generated in the electric board and passing through the support.

[Embodiment 3]
1. Configuration of the Radiation Detector Fig. 7 is a cross-sectional view of a radiation detector 600 according to the third embodiment.

The radiation detector 600 according to this embodiment differs from the first embodiment in that the support 610 has a plate material 620 for increasing the strength of the support. Therefore, the same components as those in the first embodiment are given the same reference numerals and their description is omitted.

As shown in FIG. 7, the radiation detector 600 has a radiation detection unit 110 that converts radiation into an image signal, and a support 610 that supports the radiation detection unit 110. The support 610 has a plate material 620 for increasing the strength of the support. The radiation detection unit 110 and the support 410 are housed inside a housing 130. In addition, electronic components such as an electric board 140 and a battery 150 may be housed inside the housing 130.

It is preferable that the plate material 620 is disposed in a portion of the support 610 where the thickness _t2 in the radiation receiving direction is the thinnest. By disposing the plate material 620 in this portion of the support 610, it is possible to improve the strength against partial bending and compression without excessively increasing the weight of the support 610. Note that the plate material 620 may be disposed in a portion of the support 610 other than the portion where the thickness _t2 is the thinnest, as long as the weight of the support 610 is not excessively increased.

As shown in FIG. 7, the support 620 is preferably formed integrally with the plate material 620. In this embodiment, the plate material 620 may be disposed between the support 610 and the radiation detection unit 110. The support 610 has the plate material 620, which can improve the strength of the support 610. In this embodiment, "integrally formed" means that the plate material is joined to the support (beads method foam) without using adhesive or mechanical joining. In this embodiment, as described later, the plate material 620 and the support 610 can be formed integrally by foaming the resin particles 240 in contact with the plate material 620.

There are no particular limitations on the plate material 620, so long as it can increase the strength of the support 610 against partial bending and compression. Examples of plate materials include polystyrene, polyethylene, modified polyphenylene ether resin, polycarbonate, ABS (acrylonitrile-butadiene-styrene) resin, polyethylene terephthalate, and the like. Of the above plate materials, it is preferable that the plate material 620 is made of the same material as the support material, such as polystyrene, polyethylene, or modified polyphenylene ether resin. By making the plate material 620 of the same material as the support material, it is possible to increase the strength by fusing and integrating them during molding.

The thickness of the plate material is preferably 0.5 mm or more and 1.5 mm or less. By having the support have a plate material of 0.5 mm or more, the strength of the support in the direction in which it receives radiation can be increased. By having the support have a plate material of 1.5 mm or less, the weight of the support can be prevented from becoming excessively heavy.

2. Method for manufacturing a support The method for manufacturing a support according to the third embodiment includes a step of impregnating resin particles with a foaming agent to manufacture resin particles containing a foaming agent, a step of putting the resin particles containing a foaming agent into a molding vessel, and a step of heating and foaming the resin particles inside the molding vessel. The method for manufacturing a support according to the third embodiment preferably includes a step of smoothing the surface of the put-in resin particles after the step of putting the resin particles into the molding vessel and before the step of foaming. In addition, the method for manufacturing a support according to the third embodiment may include a step of manufacturing resin particles containing a foaming agent and a step of pre-foaming the resin particles containing a foaming agent, as in the first embodiment. Note that the same steps as those in the method for manufacturing a support according to the first embodiment will not be described.

2-1. Step of manufacturing resin particles containing a foaming agent The step of manufacturing resin particles containing a foaming agent is a step of impregnating resin particles with a foaming agent to manufacture expandable particles. The above step can be performed in the same manner as in the first embodiment.

2-2. Step of pre-expanding resin particles This is a step of placing resin particles containing a foaming agent in a pre-expanding tank and heating them to pre-expand. This step can be performed in the same manner as in the first embodiment.

2-3. Step of Feeding Pre-Expanded Resin Particles into a Molding Vessel The step of feeding pre-expanded resin particles into a molding vessel is a step of feeding pre-expanded resin particles into a molding vessel.

Figures 8A to 8E are schematic diagrams illustrating the process of introducing resin particles 240 into a molding vessel 700. Figure 8A is a cross-sectional view of a molding vessel 700 used in embodiment 3. As shown in Figure 8A, the molding vessel 700 has at least a blocking portion 710, a resin particle receiving portion 720, and an introduction port 730. Figures 8C to 8E will be described in the process of smoothing the resin particles described below.

Figure 8B is a cross-sectional view showing the state in which the resin particles 240 and the plate material 620 are arranged in the resin receiving section 720. The resin particles 240 can be introduced into the molding container 700 in the same manner as in embodiment 1.

As shown in FIG. 8B, the plate material 620 is preferably placed in the resin receiving section 720 after a certain amount of resin particles 240 has been poured into the resin receiving section 720. In the third embodiment, the plate material 620 may be placed in the resin receiving section 720 before pouring the resin particles 240 into the resin receiving section 720, or may be placed after pouring the amount of resin particles 240 to be poured into the resin receiving section 720.

As shown in FIG. 8B, it is preferable to pour a certain amount of resin particles 240 into the resin receiving section 720 and place the plate material 620 on the surface of the poured resin particles 240. In this embodiment, the plate material 620 may be placed in the resin receiving section 720 before pouring the resin particles 240, or may be placed after pouring the amount of resin particles 240 to be poured into the resin receiving section 720.

Then, after the plate material 620 is placed on the surface of the resin particles 240, further resin particles 240 are poured into the resin receiving section 720 so as to cover the plate material 620 (see FIG. 8C).

At this time, the resin particles 240 containing the foaming agent that are put into the molding container 700 can be the resin particles that can be used in the first embodiment. In addition, it is preferable that the particle surface of the resin particles 240 is subjected to an antistatic treatment or that the resin particles 240 are mixed with an antistatic agent. The same antistatic agent as in the first embodiment can be used as the antistatic agent.

The molding container 700 can be the same as the molding container that can be used in embodiment 1. This allows the radiation detector 600, which has a thickness as specified in the JIS standard, to properly accommodate the radiation detection unit 110, the electric board 140, the battery 150, and the like, in addition to the support 610.

8C to 8E are cross-sectional views showing the step of smoothing the surface of resin particle 240. The step of smoothing the surface of resin particle 240 is performed after the step of putting resin particle 240 into molding container 700 and before the step of foaming. The above step can be performed in the same manner as in embodiment 1.

2-5. Step of Heating and Expanding Resin Particles Inside the Forming Container The step of heating and expanding resin particles inside the forming container is a step of expanding the resin particles to a predetermined expansion ratio after closing inlet 730 of forming container 700 with closing part 710 as shown in Fig. 8F in a state where plate material 620 is placed in forming container 700. The above step can be performed in the same manner as in embodiment 1.

In this way, as shown in FIG. 8G, a support 610 made of a bead-process foam having a plate material 620 can be obtained. Note that in this embodiment, the support is formed integrally with the plate material 620, but this is not limiting. The plate material 620 may be disposed between the support 610 and the sensor panel 140.

In this embodiment, a step of subjecting the bead method foam to an antistatic treatment may be included after the step of foaming the resin particles. The application of the antistatic agent to the surface of the support can be performed in the same manner as in embodiment 1.

(effect)
By having a plate material in the support made of a bead process foam, the strength of the thinnest portion of the support in the radiation receiving direction can be improved.

[Other embodiments]
The above-described embodiment is merely an example of a specific embodiment of the present invention, and the technical scope of the present invention should not be interpreted as being limited by the above-described embodiment. The present invention can be embodied in various forms without departing from the spirit or main characteristics of the present invention.

Although the second embodiment describes a support having a shielding material, and the third embodiment describes a support having a plate material, the present invention is not limited to this. For example, both a shielding material and a plate material may be disposed inside the support. In addition, the shape of the forming container is not limited to the shapes described in the first to third embodiments, and any forming container can be used, as long as the formed support can be housed in the radiation detector.

The above-mentioned radiation imaging device may be a fixed type that is fixed to a hospital or the like, or a portable type that can be carried around. A radiation detector having the above-mentioned support is lightweight and easy to carry, and the strength against shocks during transportation is increased by the bead method foam, making it particularly suitable for a portable radiation imaging device.

The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these.

[Method of manufacturing a foam by the bead method]
The bead process foam was produced by the following procedure.

(Method for producing bead process foam 1)
Resin particles having a diameter of 0.5 mm (expandable polystyrene beads "Eslen Beads", manufactured by Sekisui Chemical Industry Co., Ltd.) were placed in a pressure vessel and heated with steam at 100°C under normal pressure to pre-expand the resin particles. The resin particles after pre-expanding (pre-expanded resin particles) had a diameter of 0.8 mm. The pre-expanded resin particles were then filled into a molding vessel (the dimensions of the inner surface of the vessel were such that the support body having a cross section shown in FIG. 2 could be molded, and the thickness of the thinnest part in the direction of receiving radiation was 2 mm), the molding vessel was placed in a furnace, and steam at 110 to 120°C was filled into the furnace and the molding vessel for about 1 to 2 minutes. The obtained bead-method foam was taken out of the molding vessel and dried in a drying device to obtain a bead-method foam 1. The expansion ratio of the obtained bead-method foam 1 was 5 times, as determined by dividing the density of the resin particles, which are the material of the bead-method foam, by the density of the bead-method foam 1 after expansion.

(Production methods of beads-based foams 2 to 4)
For the Bead Process Foams 2 to 4, pre-expanded resin particles obtained by the same method as in Example 1 were used and carbon dioxide gas was allowed to penetrate under the same conditions. The pre-expanded resin particles were then filled into the same molding vessel as for the Bead Process Foam 1, and the temperature and time of the steam filling into the molding vessel were adjusted so as to achieve the expansion ratios shown in Table 1, thereby obtaining the Bead Process Foams 2 to 4. The expansion ratios of the Bead Process Foams 2 to 4 were determined in the same manner as for the Bead Process Foam 1.

[evaluation]
The beads method foams 1 to 4 obtained by the above production method were evaluated for strength against load.

(Evaluation Method)
For the above-mentioned bead-process foams 1 to 4, a load of 0.2 MPa was applied assuming "lying" and a load of 1.4 MPa assuming "full load (standing on one leg)," and the deformation of the bead-process foams 1 to 4 was observed using a precision universal testing machine "Autograph" (manufactured by Shimadzu Corporation).

(Evaluation Criteria)
◎: No deformation is observed. ○: Almost no deformation is observed. △: Deformation is observed, but at a level that does not pose a problem in practical use. ×: Deformation is so great that it cannot be used in practical use.

The above evaluation results are shown in Table 1.

It was found that the support made of the bead-processed foam of the present invention does not deform even if the foaming ratio is 30 times or less when photographed in a supine position, and does not deform even if the foaming ratio is 10 times or less when fully loaded (one leg).

The support of the present invention is suitable for use in radiation detectors because it maintains sufficient strength even when the weight of the support is reduced.

10 Radiation imaging device 20 Radiation irradiation device 30 CPU
40 Cradle device 50 X-ray irradiation unit 60 Display unit 100, 400, 600 Radiation detector 110 Radiation detection unit 111 Radiation detection element 112 Substrate 120, 410, 610 Support 130 Housing 131 Main body 132 Bottom plate 133 Top plate 134, 135 Side plate 140 Electrical board 150 Battery 200, 300, 500, 700 Forming container 210, 310, 510, 710 Closing unit 220, 320, 520, 720 Resin particle receiving unit 230, 330, 530, 730 Feeding port 240 Resin particle 250 Squeegee 420 Shielding material 620 Plate material t Thickness

Claims (21)

a radiation detection unit that detects radiation irradiated onto a subject ;
a support member that is accommodated in a housing and supports the radiation detection unit inside the housing ;
A radiation detector comprising:
The support is made of a bead process foam material. The radiation detector according to claim 1, wherein the radiation detection unit has a radiation detection element and a flexible substrate that supports the radiation detection element. The radiation detector according to claim 1 or claim 2, wherein the support is made of a bead-process foam having an expansion ratio of 5 to 30 times. The radiation detector according to any one of claims 1 to 3, wherein the support is made of a bead-process foam having an expansion ratio of 5 to 10 times. The radiation detector according to any one of claims 1 to 4, wherein the thickness of the thinnest part of the support in the direction in which the radiation is received is 1.5 mm or more and 5.0 mm or less. The radiation detector according to any one of claims 1 to 5, wherein the support has a shielding material for blocking electromagnetic waves. The radiation detector of claim 6, wherein the support is integrally formed with the shielding material. The radiation detector according to any one of claims 1 to 6, wherein the support has a plate material for increasing the strength of the support in the direction in which the radiation is received. The radiation detector of claim 8, wherein the support is integrally formed with the plate material. The radiation detector according to any one of claims 1 to 9, wherein the bead-method foam contains an antistatic agent dispersed therein. The radiation detector according to any one of claims 1 to 10, wherein the surface of the bead-method foam is coated with an antistatic agent. A radiation imaging device having a radiation irradiation device and a radiation detector according to any one of claims 1 to 11, which is disposed at a position for receiving radiation irradiated from the radiation irradiation device. A support made of a bead-processed foam material, used in the radiation detector according to any one of claims 1 to 11. A step of introducing resin particles containing a blowing agent into a molding vessel;
A step of expanding the resin particles by heating inside the molding container;
having
A method for manufacturing a support used in a radiation detector , which is housed inside a housing and supports a radiation detection unit that detects radiation irradiated onto a subject inside the housing . After the step of introducing the resin particles into a molding vessel and before the step of expanding,
smoothing the introduced resin particles;
A method for producing a support used in the radiation detector according to claim 14. The method for manufacturing a support for use in a radiation detector according to claim 14 or 15, wherein the step of foaming the resin particles foams resin particles whose particle surfaces have been subjected to an antistatic treatment or resin particles mixed with an antistatic agent. A method for manufacturing a support used in a radiation detector according to any one of claims 14 to 16, in which, in the step of pouring resin particles into a molding container, the resin particles are poured so as to come into contact with a shielding material for blocking electromagnetic waves or a plate material for increasing the strength of the support. The method for manufacturing a support used in a radiation detector according to any one of claims 14 to 17, wherein the foaming step is a step of foaming the resin particles to an expansion ratio of 5 to 30 times. The method for manufacturing a support used in a radiation detector according to any one of claims 14 to 17, wherein the foaming step is a step of foaming the resin particles to an expansion ratio of 5 to 10 times. In the step of introducing the resin particles into a molding vessel,
The method for producing a support used in a radiation detector according to any one of claims 14 to 19, wherein the resin particles are charged into a molding container having a thickness of 1.5 mm or more and 5.0 mm or less at the thinnest part. The method for producing a support used in a radiation detector according to any one of claims 14 to 20, further comprising, after the step of expanding the resin particles, a step of subjecting a molded body obtained by expanding the resin particles to an antistatic treatment.