JP2009047520A - X-ray image detection panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray image detection panel having high sharpness, capable of cutting diffused fluorescence. <P>SOLUTION: This panel has an obliquely-incoming light cutting layer for cutting fluorescence entering with an incident angle which is larger than a prescribed angle in fluorescence emitted from a scintillator layer, between the scintillator layer and a photoelectric conversion layer. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an X-ray image detection panel.

  Conventionally, X-ray images typified by X-ray images have been widely used for diagnosis of medical conditions in the medical field. In recent years, digital X-ray image detection devices such as FPD (Flat Panel Detector) have also appeared, and X-ray images can be acquired as digital information and image processing can be performed freely. Can be transmitted.

  There are two types of FPDs: a direct type that converts X-rays directly into electrical signals, and an indirect type that converts X-rays into fluorescent light such as visible light once by a scintillator. The indirect type is an X-ray in which a scintillator layer that emits fluorescence when irradiated with X-rays, and a photoelectric conversion layer in which light receiving elements that receive the fluorescence are two-dimensionally arranged along a light receiving surface are stacked. This is an image detection panel, which is easy to manufacture compared to the direct type, has low temperature dependency, and can eliminate the need for applying a high voltage. However, since the fluorescent light isotropically emits and diffuses in the scintillator layer, not only the fluorescent light emitted in the vicinity but also the fluorescent light emitted at a distant place is incident on the light receiving element, which is sharper than the direct type. Has been recognized as inferior.

Therefore, as a technique for improving the sharpness in the indirect FPD, a technique using a scintillator in which columnar crystals grown substantially perpendicular to the light receiving surface is arranged is known (for example, see Patent Document 1). In this technique, the fluorescence emitted in the columnar crystal is repeatedly reflected on the wall surface of the columnar crystal and reaches the light receiving element so that the fluorescence does not diffuse widely in the direction parallel to the light receiving surface.
JP 2005-148060 A

  However, even in such a columnar crystal scintillator, in order to suppress the amount of X-ray exposure to the subject, sharpness is increased by increasing the thickness so that the X-ray quantum motor noise is reduced even if the X-ray irradiation amount is low. There is a problem of lowering.

  Of the fluorescence emitted from the scintillator layer, the component emitted in the direction within the total reflection angle of the wall surface of the columnar crystal is repeatedly reflected on the wall surface of the columnar crystal, but emitted in the direction closer to the light receiving surface. The ratio of the light reflected from the wall surface of the columnar crystal decreases, and the light passes through the wall surface of the columnar crystal. And if the scintillator layer is thick, the fluorescence emitted in the direction closer to the light receiving surface is not easily reached, but diffuses widely in the direction parallel to the light receiving surface, so the sharpness may be inferior. I understood.

  The present invention has been made in view of the above problems, and is an indirect type FPD having advantages over a direct type, and an object thereof is to improve sharpness.

(Claim 1)
In an X-ray image detection panel in which a scintillator layer that emits fluorescence when irradiated with X-rays and a photoelectric conversion layer in which light receiving elements that receive the fluorescence are two-dimensionally arranged along a light receiving surface are stacked ,
Between the scintillator layer and the photoelectric conversion layer, on the at least one surface perpendicular to the light receiving surface, the fluorescence incident from the scintillator layer with an incident angle larger than a predetermined angle is cut. An X-ray image detection panel comprising an oblique light cut layer.
(Section 2)
The X-ray image detection panel according to claim 1, wherein the oblique incident light cut layer is provided with a plurality of flat light shielding portions provided substantially perpendicular to the light receiving surface.
(Section 3)
In an X-ray image detection panel in which a scintillator layer that emits fluorescence when irradiated with X-rays and a photoelectric conversion layer in which light receiving elements that receive the fluorescence are two-dimensionally arranged along a light receiving surface are stacked ,
Between the scintillator layer and the photoelectric conversion layer, on any surface perpendicular to the light receiving surface, the fluorescence incident from the scintillator layer at an incident angle larger than a predetermined angle is cut. An X-ray image detection panel comprising an oblique light cut layer.
(Claim 4)
The oblique light cut layer has a plurality of layers in which a plurality of flat light shielding portions provided substantially perpendicularly to the light receiving surface are arranged in parallel, and the parallel arrangement directions of the light shielding portions of the layers intersect each other. Item 4. The X-ray image detection panel according to Item 3, wherein the X-ray image detection panel is laminated in such a manner.
(Section 5)
The X-ray image according to claim 2 or 4, wherein the light shielding portions are arranged side by side so that an angle with respect to any arrangement direction of the light receiving elements arranged two-dimensionally is 15 degrees or more. Detection panel.
(Claim 6)
The X-ray image detection panel according to any one of claims 1 to 5, wherein the scintillator layer is formed by arranging columnar crystals grown substantially perpendicular to the light receiving surface.
(Claim 7)
The scintillator layer includes a phosphor of an alkali metal halide or an alkaline earth metal halide,
Any one of Items 1 to 6, further comprising a protective layer that protects the oblique light cut layer from the phosphor and the deliquescent material of the phosphor between the scintillator layer and the oblique light cut layer. An X-ray image detection panel according to claim 1.

  According to the present invention, sharpness is improved. Of at least one surface perpendicular to the light-receiving surface, or any surface perpendicular to the light-receiving surface, out of the fluorescent light diffused widely in the direction parallel to the light-receiving surface before entering the oblique light-cut layer Fluorescence incident at an incident angle with respect to the light cut layer larger than a predetermined angle is absorbed by the oblique light cut layer. For this reason, it is presumed that most of the fluorescent light diffused widely in the direction parallel to the light receiving surface before entering the light receiving surface is absorbed by the oblique light cut layer, and the sharpness is improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The best mode column for carrying out the invention indicates a mode that the inventor recognizes as best for carrying out the invention, and the present invention is not limited to these. Further, in the best mode column for carrying out the invention, there are expressions that seem to determine, define, or define terms used in the scope of the invention and claims, but these are only to the invention. It is an expression for specifying the form that the person recognizes as the best, and does not specify or limit the terms used in the scope of the invention or the claims.
<Embodiment 1>
(Configuration of X-ray image detection panel)
FIG. 1 is a diagram schematically illustrating a cross section of the X-ray image detection panel according to the first embodiment. FIG. 2 is a partially enlarged view of FIG. For convenience, the horizontal direction in the figure is the X direction, the depth direction is the Y direction, and the vertical direction is the Z direction.

  In the X-ray image detection panel 1, a support 11 such as a glass substrate, a photoelectric conversion layer 12, an oblique light cut layer 13, a protective layer 14, a scintillator layer 15, and a support 16 are sequentially stacked. X-rays are irradiated from the scintillator layer 15 side.

  The scintillator layer 15 receives X-rays transmitted through the subject and emits fluorescence having an intensity corresponding to the received X-ray dose. The scintillator layer 15 is formed by applying a coating liquid in which phosphor particles such as CsI and CsBr are dispersed in a solvent together with a binder resin on a support 16 such as a resin film. It is a layer in which particles are dispersed.

  When irradiated with X-rays, the phosphor in the scintillator layer 15 emits light in the same direction, and the emitted fluorescence travels through the resin. At this time, the traveling direction is changed by reflection, refraction, scattering, or the like with another phosphor, or scattered in the resin, but proceeds toward the oblique light cut layer 13. That is, light having a small incident angle with respect to the oblique light cut layer has a small amount of light diffused widely in the scintillator layer 15, while light entering the oblique light cut layer 13 obliquely, ie, oblique light. The light having a large incident angle with respect to the cut layer has many light components diffused widely in the scintillator layer 15.

  The protective layer 14 has moisture resistance and encloses the support 16 on which the scintillator layer 15 is formed. Thereby, it is suppressed that moisture permeates into the scintillator layer 15 from the outside. In addition, the protective layer 14 is formed by the phosphor in the scintillator layer 15 diffusing into the oblique incident light cut layer 13 or the deliquescent of this phosphor generated by moisture absorption reaching the oblique incident light cut layer 13, causing oblique incident light. It prevents that the light shielding part 131 of the cut layer 13 corrodes. The scintillator layer 15 using a phosphor of an alkali metal halide or an alkaline earth metal halide is easily deliquescent due to moisture absorption. The deliquescent corrodes the metal. As the protective layer 14, for example, a material such as polyethylene terephthalate resin or polypropylene resin can be used.

  The oblique light cut layer 13 includes a plurality of flat light-shielding portions 131 arranged in parallel in the arrangement direction (X direction) of the photodiodes 121 with the Y direction having a plane parallel to the YZ plane as the parallel direction. Details will be described later.

  The photoelectric conversion layer 12 includes a photodiode 121 that receives the fluorescence from the oblique light cut layer 13 and generates charges, and a TFT 122 that reads the charges generated in the photodiode 121. A plurality of photodiodes 121 and TFTs 122 are arranged in a two-dimensional shape (X direction and Y direction in the figure). The photodiode 121 corresponds to the light receiving element of the present invention.

(Slant incident light cut layer)
FIG. 3 is a partial perspective view of the oblique light cut layer 13 according to the present embodiment. FIG. 4 is a partially enlarged view of the vicinity of the oblique incident light cut layer 13 in FIG. Corresponding to FIG. 2, X, Y, and Z directions are shown.

  As shown in FIG. 3, in the oblique light cut layer 13, a plurality of flat light-shielding portions 131 having a plane parallel to the YZ plane are arranged in parallel in the X direction via the light transmission portion 132.

  The light transmitting portion 132 is formed of a highly transparent material because it is necessary to transmit the incident fluorescence without being attenuated. For example, materials such as silicon resin, olefin resin, urethane resin, acrylic resin, cellulose resin, polyester resin, and polycarbonate resin can be used.

  The light shielding unit 131 absorbs light having a fluorescence wavelength, and is provided substantially perpendicular to the light receiving surface. The term “substantially perpendicular” refers to an angle that cuts light incident from the direction perpendicular to the oblique light cut layer 13 to a minimum and cuts light incident on the oblique light cut layer 13 at an angle larger than a predetermined angle. I just need it.

  On the XZ plane perpendicular to the light receiving surface, as shown in FIG. 4, the oblique incident light cut layer 13 cuts the incident fluorescence at an angle larger than the predetermined angle θ1 with respect to the Z direction. As can be understood from FIG. 3, the fluorescence F with the incident angle θ> θ1 cannot pass through the light transmission part 132 as it is, but is always incident on the light shielding part 131. For this reason, it is possible to suppress the fluorescence F from further entering the incident direction and entering the photodiodes 121 other than the desired photodiode 121. As a result, the fluorescence diffusing in the X direction in the figure can be cut, and an X-ray image with high sharpness can be obtained.

  As a material of the light shielding portion 131, a substance that absorbs fluorescence can be used. That is, a substance having a high absorption rate at the fluorescence wavelength can be used. For example, a dark metal oxide, pigment, or dye can be used at the fluorescence wavelength.

  In addition, when the material of the light shielding part 131 is a metal, it is considered that the deliquescent material in the scintillator layer 15 caused by moisture absorption enters the oblique light cut layer 13 and the light shielding part 131 is corroded. In the embodiment, since the protective layer 14 is provided between the scintillator layer 15 and the oblique light cut layer 13, corrosion of the light shielding part 131 can be prevented.

The light shielding portion 131 is provided substantially perpendicular to the light receiving surface. Note that “substantially perpendicular to the light receiving surface” means that the thickness L of the oblique light cut layer 13, the thickness T of the light shielding part 131, and the average distance provided by the light shielding part 131 with respect to the direction perpendicular to the light receiving surface An angle with respect to D is a function Tan ⁻¹ (0.1 × (DT) / L) or less.

Further, the thickness T of the light shielding part 131 may be a thickness that can maintain the light shielding property, and the preferable thickness T varies greatly depending on the material, but it is 1 μm or more, particularly 10 μm or more. T / D affects the absorption rate of light perpendicularly incident on the oblique light cut layer 13, and is preferably 0.1 or less, and particularly preferably 0.05 or less.
In order to reduce the thickness of the X-ray image detection panel, the thickness L of the oblique light cut layer 13 is preferably thin, and is generally 20 μm or less, particularly 10 μm or less. Further, the predetermined angle for cutting the light incident on the obliquely incident light cut layer 13 at a larger angle is preferably 45 ° or more, and therefore (DT) / L is preferably 1 or more. Furthermore, (DT) / L is preferably 2 or more. Further, (DT) / L is preferably 10 or less.

  The average interval D of the light blocking portions 131 of the oblique light cut layer 13 is appropriately set in consideration of the above. Note that the smaller the length L, the interval D, and the thickness T of the light shielding portion 131, the more difficult the manufacturing becomes. Therefore, the length L, the interval D, and the thickness T of the light shielding portion 131 are set in consideration of the manufacturing cost.

  It is preferable that the arrangement intervals of the respective light shielding portions 131 in the oblique incident light cut layer 13 are equal intervals in order to suppress variations in the amount of light incident on each light receiving element. Similarly, it is preferable that the light receiving elements are arranged at equal intervals. In addition, when the arrangement interval of the light shielding portions 131 is equal, the thickness of the light shielding portions 131 is equal, and the thickness of the oblique incident light cut layer 13 is also constant, the ability to cut fluorescence differs for each light receiving element. No sharpness variation can be suppressed. Note that if at least one of the arrangement interval of the light shielding portions 131, the thickness of the light shielding portions 131, or the thickness of the oblique light cut layer 13 varies, the incident angle is larger than a predetermined angle in a certain light receiving element. Fluorescence incident at an angle is cut, but with some other light receiving elements, there is variation in the ability to cut the fluorescence, such as cutting off the incident fluorescence at an angle greater than a certain angle smaller than the predetermined angle. As a result, the sharpness varies.

  Further, when the light shielding part 131 and the light receiving elements are arranged at equal intervals, moire may occur. For this reason, it is preferable that both of the two arrangement directions (both X and Y directions) of the light receiving elements arranged in two dimensions are at an angle of 15 degrees or more with respect to the arrangement direction of the light shielding portions 131.

  Moreover, it is preferable that the space | interval D of the light-shielding part 131 of the oblique incident light cut layer 13 satisfy | fills D <1 / 3xP with respect to the arrangement space P (refer FIG. 2) of a light receiving element. The occurrence of moire can be suppressed while suppressing variations in the amount of light received between the light receiving elements due to the difference in the number of light shielding portions 131 on each light receiving element.

  For example, the oblique light cut layer 13 is formed by alternately laminating the material of the light shielding portion 131 having a thickness T and the material of the light transmitting portion 132 having a thickness substantially equal to the distance D, and then in a direction perpendicular to the lamination direction. It can be produced by cutting at intervals equivalent to the length L.

  FIG. 5 is a conceptual diagram showing the light reception level of the fluorescence received by the photodiode 121a when the X-ray irradiation position is changed with respect to the scintillator layer 15. As shown in FIG.

  FIG. 5A shows, as an example, a state in which X-rays are irradiated from vertically above a target photodiode 121a.

  FIG. 5B shows the state when the X-ray irradiation position in FIG. 5A is moved in the X direction and the relative positional relationship between the X-ray irradiation position and the photodiode 121a is changed. The light reception level received by the photodiode 121a in the center is conceptually shown.

  The light reception level at X = 0 in FIG. 5B corresponds to the light reception level in a state in which X-rays are irradiated from vertically above the photodiode 121a in FIG. Further, the light reception level when moved in the positive direction of the X direction from the X-ray irradiation position in FIG. 5A is the X-axis from the X-ray irradiation position (0 point of the X axis) in FIG. It shows according to the distance of the positive direction. Similarly, the light reception level when moved in the negative X direction from the X-ray irradiation position in FIG. 5A is the X-axis from the X-ray irradiation position (X-axis zero point) in FIG. Shown according to the distance of the negative direction.

  FIG. 5B shows the characteristics of the received light level with and without the obliquely incident light cut layer 13. “No cut” means that the protective layer 14 is provided directly on the photoelectric conversion layer 12, that is, there is no oblique light cut layer 13, the support 11, the photoelectric conversion layer 12, the protective layer 14, and the scintillator layer. 15 and the characteristic in case the support body 16 is laminated | stacked in order. On the other hand, “with cut” means that when the oblique light cut layer 13 is provided on the photoelectric conversion layer 12 and the protective layer 14 is provided on the oblique light cut layer 13, that is, the support 11, the photoelectric conversion. The characteristics in the case where the layer 12, the oblique light cut layer 13, the protective layer 14, the scintillator layer 15, and the support 16 are sequentially laminated are shown. In either case, the light reception level decreases as the X-ray irradiation position moves away from directly above the photodiode 121a.

  “No cut” has the broadest characteristic, and fluorescence is received even if the X-ray irradiation position is relatively far away. This is because the fluorescence in the scintillator layer 15 isotropically diffuses and there is no oblique light cut layer 13 that absorbs fluorescence with a large incident angle.

  “With cut” has the oblique light cut layer 13, so that the fluorescence in the scintillator layer 15 diffuses isotropically, but the fluorescent light having a large incident angle to the oblique light cut layer 13 is obliquely incident. It is absorbed by the light cut layer 13 and becomes sharper than “no cut”.

  That is, when the oblique light cut layer 13 is used, the spread fluorescence is suppressed from entering the photoelectric conversion layer 12, and the fluorescence generated by the X-rays incident on the region other than vertically above the photodiode 121a is reflected by the photodiode. The incident on 121a is suppressed.

  As described above, according to the present embodiment, the oblique incident light cut layer 13 cuts the fluorescence incident on the oblique incident light cut layer 13 at an angle larger than a predetermined angle. Fluorescence incident at an angle larger than the predetermined angle can be prevented from entering the photoelectric conversion layer 12. Therefore, it is possible to suppress the widely diffused fluorescence from entering the photoelectric conversion layer 12, and the fluorescence generated by the X-rays incident vertically above the photodiode 121a is incident on the photodiode 121 other than the photodiode 121a. It can be suppressed. As a result, an X-ray image with high sharpness can be obtained.

Further, if the protective layer 14 is provided between the scintillator layer 15 and the oblique light cut layer 13 as in the present embodiment, the deliquescence in the scintillator layer 15 caused by moisture absorption is absorbed by the oblique light cut layer 13. It is possible to prevent the light shielding part 131 from corroding and corroding.
<Embodiment 2>
The present embodiment is a modification of the first embodiment. Hereinafter, differences from the first embodiment will be described. The points not described below are the same as in the first embodiment.

(Configuration of X-ray image detection panel)
The overall image of the X-ray image detection panel of the second embodiment is the same as that of the first embodiment shown in FIG. FIG. 6 is a partially enlarged view schematically showing a cross section of the X-ray image detection panel of the second embodiment. For convenience, the horizontal direction in the figure is the X direction, the depth direction is the Y direction, and the vertical direction is the Z direction.

  The scintillator layer 15 is formed by depositing a material such as CsI or CsBr on a support 16 such as a resin film by vapor deposition, and is substantially perpendicular to the light receiving surface (the plane in the XY direction in FIG. 1). A large number of columnar crystals 151 extending in the stacking direction (Z direction in FIG. 1) are formed. A minute gap C is formed between the columnar crystals 151.

  The refractive indexes of the columnar crystals 151 are, for example, CsI: 1.7 to 1.8, CsBr: 1.5 to 1.7, and 1.5 or more. On the other hand, air exists in the gap C between the columnar crystals 151, and its refractive index is about 1. For this reason, among the fluorescence emitted in the columnar crystal 151, the fluorescence in the direction close to the Z direction proceeds while being totally reflected in the columnar crystal 151. It has a so-called light guide effect. The total reflection angles are, for example, CsI: 34.4 ° and CsBr: 41.1 °. That is, in the case of CsI, the fluorescence incident on the interface at an angle of 34.4 ° or more with respect to the normal direction of the interface between the columnar crystal 151 and the gap C is totally reflected at the interface and passes through the columnar crystal 151. Go ahead.

  However, the fluorescence incident on the interface at an angle smaller than 34.4 ° with respect to the normal direction of the interface between the columnar crystal 151 and the gap C decreases as the angle decreases. Thus, the ratio of diffusion across the columnar crystals increases.

  If the columnar crystal 151 is grown in a stacking direction substantially perpendicular to the light receiving surface, and the surface of the columnar crystal 151 is smooth, the normal direction of the interface between the columnar crystal 151 and the gap C Is nearly parallel to the light receiving surface (the plane in the XY direction in FIG. 1).

  Accordingly, the fluorescent light traveling at a small incident angle with respect to the light receiving surface reaches the light receiving surface while reflecting inside the columnar crystal 151, but the fluorescent light traveling at an angle close to the parallel to the light receiving surface is between the columnar crystal 151 and the gap C. The ratio of reflection at the interface decreases, and the ratio of diffusion across the columnar crystals increases.

  The protective layer 14 has moisture resistance and encloses the support 16 on which the scintillator layer 15 is formed. Thereby, it is suppressed that moisture permeates into the scintillator layer 15 from the outside. Further, the protective layer 14 is formed by the phosphor in the scintillator layer 15 generated by moisture absorption diffusing into the oblique incident light cut layer 13, or the deliquescent of this phosphor reaches the oblique incident light cut layer 13, causing oblique incident light. Corrosion of the light shielding part 131 of the cut layer 13 is suppressed. The scintillator layer 15 using the alkali metal halide or alkaline earth metal halide such as CsI as the phosphor is easily deliquescent by moisture absorption. The deliquescent corrodes the metal. As the protective layer 14, for example, a material such as polyethylene terephthalate resin or polypropylene resin can be used.

  In the oblique light cut layer 13, a plurality of flat light shielding portions 131 having a plane parallel to the YZ plane are arranged in parallel in the arrangement direction (X direction) of the photodiodes 121. Details will be described later.

  The photoelectric conversion layer 12 includes a photodiode 121 that receives the fluorescence from the oblique light cut layer 13 and generates charges, and a TFT 122 that reads the charges generated in the photodiode 121. A plurality of photodiodes 121 and TFTs 122 are arranged in a two-dimensional direction (X direction and Y direction in the drawing) in pairs. The photodiode 121 corresponds to a light receiving element that receives fluorescence.

  The oblique light cut layer 13 of the second embodiment is the same as the oblique light cut layer 13 of the first embodiment.

  FIG. 7 is a conceptual diagram showing the light reception level of the fluorescence received by the photodiode 121a when the X-ray irradiation position is changed with respect to the scintillator layer 15. FIG. 7A shows a state in which X-rays are irradiated immediately above the target photodiode 121a as an example. FIG. 7B shows a photo when the X-ray irradiation position in FIG. 7A is moved in the X direction, that is, when the relative positional relationship between the X-ray irradiation position and the photodiode 121a is changed. The light reception level received by the diode 121a is conceptually shown.

  The light reception level at X = 0 in FIG. 7B corresponds to the light reception level in a state where X-rays are irradiated immediately above the photodiode 121a in FIG. 7A. Further, the light reception level when moved in the positive direction in the X direction from the X-ray irradiation position in FIG. 7A is the X-axis from the X-ray irradiation position (0 point of the X axis) in FIG. It shows according to the distance of the positive direction. Similarly, the light reception level when moved in the negative X direction from the X-ray irradiation position in FIG. 7A is the X-axis from the X-ray irradiation position in FIG. Shown according to the distance of the negative direction.

  FIG. 7B shows the light receiving level when there is no oblique light cut layer 13 and when there is the oblique light cut layer 13. “No cut” means that the protective layer 14 is provided directly on the photoelectric conversion layer 12, that is, there is no oblique light cut layer 13, the support 11, the photoelectric conversion layer 12, the protective layer 14, and the scintillator layer. 15 and the characteristic in case the support body 16 is laminated | stacked in order. “With cut” means that the oblique light cut layer 13 is provided on the photoelectric conversion layer 12 and the protective layer 14 is provided on the oblique light cut layer 13, that is, the support 11 and the photoelectric conversion layer 12. The characteristics when the oblique light cut layer 13, the protective layer 14, the scintillator layer 15, and the support 16 are sequentially laminated are shown. In either case, the light reception level decreases as the X-ray irradiation position moves away from directly above the photodiode 121a.

  The “no cut” in the second embodiment is sharper than the “no cut” in the first embodiment because most of the fluorescence in the scintillator layer 15 is guided in the growth direction of the columnar crystals and the diffusion of the fluorescence is suppressed. It becomes a characteristic.

  “With cut” in the second embodiment has the sharpest characteristic. This is because most of the fluorescence in the scintillator layer 15 is guided in the growth direction of the columnar crystals to suppress the diffusion of the fluorescence, and the fluorescence with a large incident angle to the oblique light cut layer 13 is caused by the oblique light cut layer 13. By being absorbed.

  That is, the columnar crystal can prevent the fluorescence from spreading, and the oblique incident light cut layer 13 can prevent the spread fluorescence from being incident on the photoelectric conversion layer 12. It is possible to effectively suppress the fluorescence generated by the incident X-rays from entering the photodiode 121 other than the photodiode 121a. As a result, an X-ray image with high sharpness can be obtained.

  In addition, when the scintillator layer 15 provided with a large number of columnar crystals with minute gaps is used as in the present embodiment, the diffusion of fluorescence is suppressed by the light guide effect, and crosstalk is further suppressed and high sharpness is achieved. An X-ray image can be obtained.

Further, if the protective layer 14 is provided between the scintillator layer 15 and the oblique light cut layer 13 as in the present embodiment, the deliquescence in the scintillator layer 15 caused by moisture absorption is absorbed by the oblique light cut layer 13. It is possible to prevent the light shielding portion 131 from corroding due to intrusion into the light.
<Embodiment 3>
The third embodiment is a modification of the first and second embodiments. Hereinafter, differences from the first and second embodiments will be described. Note that points not described below are the same as those in the first and second embodiments.

  FIG. 8 is a partial perspective view of the oblique incident light cut layer 13 cut along three planes (A-A ′ plane, B-B ′ plane, and C-C ′ plane). In the first and second embodiments. As the oblique incident light cut layer, an oblique incident light cut layer in which a plurality of flat light shielding portions 131 having a plane parallel to the YZ plane are arranged in parallel is used. On the other hand, in the third embodiment, as shown in FIG. 8, each of the scintillator layers 15 shown in the first and second embodiments has a flat light-shielding surface having a plane parallel to the XZ plane (for example, the CC ′ plane). An oblique light cut upper layer 135 having a plurality of portions 136 arranged side by side and an oblique light cut lower layer 137 having a plurality of flat light shielding portions 138 having a plane parallel to the YZ plane (for example, the BB ′ surface). An oblique light cut layer that is used in combination and laminated so that the juxtaposed directions are orthogonal to each other is used. Here, the oblique light cut upper layer 135 and the oblique light cut lower layer 137 are respectively equivalent to the oblique light cut layers described in the first and second embodiments. As a result, the fluorescence obtained at an incident angle larger than a predetermined angle on any surface perpendicular to the light receiving surface of the photodiode 121 is cut. That is, on any surface perpendicular to the light receiving surface of the photodiode 121, the oblique light cut layer 13 for cutting the fluorescence obtained at an incident angle larger than a predetermined angle is provided.

  As a result, not only the direction in the XZ plane and the YZ plane but also the light incident on the oblique light cut layer 13 at an angle larger than a predetermined angle corresponding to the plane in any plane perpendicular to the XY plane. Will do. For example, in the A-A ′ plane that is not parallel to the XZ plane and the YZ plane in FIG. 8, incident light cuts light incident at an angle larger than the maximum allowable incident angle θa in this plane. As a result, it is possible to more effectively cut off the fluorescent light diffusing across the columnar crystals and obtain a sharp X-ray image. Accordingly, it is possible to obtain a sharp X-ray image not only in the X direction but also in the Y direction.

It is a figure which shows typically the cross section of the X-ray image detection panel which concerns on Embodiments 1-4. FIG. 2 is a partially enlarged view of FIG. 1 in the first embodiment. It is a fragmentary perspective view of the obliquely incident light cut layer 13 which concerns on Embodiment 1,2. It is the elements on larger scale of the obliquely incident light cut layer 13 in Embodiment 1,2. FIG. 5A shows a state in which X-rays are irradiated immediately above the target photodiode 121a as an example. FIG. 5B conceptually shows the light reception level received by the photodiode 121a when the X-ray irradiation position in FIG. 5A is moved in the X direction. FIG. 3 is a partially enlarged view of FIG. 1 in Embodiment 2. FIG. 7A shows a state in which X-rays are irradiated immediately above the target photodiode 121a as an example. FIG. 7B conceptually shows the light reception level received by the photodiode 121a when the X-ray irradiation position in FIG. 7A is moved in the X direction. It is a fragmentary perspective view of the oblique incidence light cut layer 13 in Embodiment 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray image detection panel 12 Photoelectric conversion layer 121 Photodiode 13 Obliquely incident light cut layer 131,138 Light-shielding part 14 Protection layer 15 Scintillator layer

Claims (7)

In an X-ray image detection panel in which a scintillator layer that emits fluorescence when irradiated with X-rays and a photoelectric conversion layer in which light receiving elements that receive the fluorescence are two-dimensionally arranged along a light receiving surface are stacked ,
Between the scintillator layer and the photoelectric conversion layer, on the at least one surface perpendicular to the light receiving surface, the fluorescence incident from the scintillator layer with an incident angle larger than a predetermined angle is cut. An X-ray image detection panel comprising an oblique light cut layer. 2. The X-ray image detection panel according to claim 1, wherein the oblique incident light cut layer includes a plurality of flat light shielding portions provided substantially perpendicular to the light receiving surface. In an X-ray image detection panel in which a scintillator layer that emits fluorescence when irradiated with X-rays and a photoelectric conversion layer in which light receiving elements that receive the fluorescence are two-dimensionally arranged along a light receiving surface are stacked ,
Between the scintillator layer and the photoelectric conversion layer, on any surface perpendicular to the light receiving surface, the fluorescence incident from the scintillator layer at an incident angle larger than a predetermined angle is cut. An X-ray image detection panel comprising an oblique light cut layer. The oblique light cut layer has a plurality of layers in which a plurality of flat light shielding portions provided substantially perpendicularly to the light receiving surface are arranged in parallel, and the parallel arrangement directions of the light shielding portions of the layers intersect each other. The X-ray image detection panel according to claim 3, wherein the X-ray image detection panel is stacked in such a manner. 5. The X-ray according to claim 2, wherein the light shielding portions are arranged side by side so that an angle with respect to any arrangement direction of the light receiving elements arranged two-dimensionally is 15 degrees or more. Image detection panel. The X-ray image detection panel according to claim 1, wherein the scintillator layer is formed by arranging columnar crystals grown substantially perpendicular to the light receiving surface. The scintillator layer includes a phosphor of an alkali metal halide or an alkaline earth metal halide,
The protective layer which protects the said incident light cut layer from the deliquescent of the said fluorescent substance and the said fluorescent substance between the said scintillator layer and the said incident light cut layer is characterized by the above-mentioned. The X-ray image detection panel according to any one of the above.

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