JP2004151007A - Radiation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation detector which can prevent generation of moires, and which can improve the resolution. <P>SOLUTION: A photoelectric conversion substrate 11 on which a plurality of photoelectric conversion elements 13 are arranged by the unit of pixel, a scintillator layer 39 which is arranged on the photoelectric conversion substrate 11 and which is stimulated by radiation so as to emit a fluorescent light, and a partition part 38 which is formed on the photoelectric conversion substrate 11 and which partitions the scintillator layer 39 by the unit of pixel are provided. The partition part 38 is composed of a side surface reflecting film 421, which is disposed so as to encompass at least a side surface of the scintillator layer 39 and which reflects the fluorescent light toward the inside of the scintillator layer 39 and a radiation grid 422, which is disposed so as to encompass the outer surface of the side surface reflecting film 421 and which absorbs the radiation. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a radiation detector, and more particularly, to an indirect radiation plane detector that detects a radiation image.
[0002]
[Prior art]
Active matrix type flat panel detectors have attracted much attention as new generation X-ray diagnostic detectors. By detecting the irradiated X-rays in this plane detector, an X-ray photographed image or a real-time X-ray image is output as a digital signal. Because it is a solid-state detector, expectations are extremely high in terms of image quality and stability. For this reason, many universities and manufacturers are engaged in R & D.
[0003]
As the first application for practical use, it has been developed for chest and general radiography for collecting still images with a relatively large X-ray dose, and has been commercialized in recent years. Commercialization is expected in the near future for applications in the cardiovascular and gastrointestinal fields, which need to clear higher technical hurdles and realize real-time video of 30 frames per second or more under fluoroscopic dose. . For this moving image application, improvement of S / N and real-time processing technology of minute signals are important development items.
[0004]
Flat detectors are roughly classified into two types: a direct type and an indirect type.
[0005]
The direct method is a method in which X-rays are directly converted into signal charges using a photoconductive film such as a-Se, and the converted signal charges are stored in a charge storage capacitor. In this direct method, photoconductive charges generated by X-rays are directly led to a charge storage capacitor by a high electric field, so that a resolution characteristic substantially defined by a pixel pitch of an active matrix can be obtained.
[0006]
On the other hand, the indirect method is a method in which X-rays are received by a scintillator layer and temporarily converted into visible light, the visible light is converted into signal charges by an a-Si photodiode or a CCD, and is guided to a charge storage capacitor. In the indirect method, the resolution is deteriorated by the optical diffusion and scattering of the visible light from the scintillator layer until it reaches the photodiode.
[0007]
However, in this indirect method, an X-ray detector provided with a partition for separating the scintillator layer for each pixel has been proposed. Thereby, the fluorescent light emitted in the scintillator layer is suppressed from being scattered or diffused in the lateral direction by the partition walls. Therefore, the fluorescence can efficiently reach the photoelectric conversion element such as the photodiode by the optical guiding effect, and the resolution characteristic is improved (for example, see Patent Document 1).
[0008]
In addition, in the indirect method, an X-ray detector provided with an X-ray grid that absorbs scattered X-rays in order to improve the contrast of a captured X-ray image has been proposed (for example, see Patent Document 2).
[0009]
[Patent Document 1]
JP-A-11-166976
[Patent Document 2]
Japanese Patent Application Laid-Open No. 2002-22842
[Problems to be solved by the invention]
In order to suppress the influence of scattered X-rays, in an X-ray detector having an X-ray grid, a photoelectric conversion substrate in which switching elements such as TFTs are arranged in a matrix in a pixel unit has an X-ray grid. A portion for shielding X-rays must be located between the switching elements. If the X-ray grid is slightly shifted in the front-rear direction and the left-right direction relatively or the X-ray grid is slightly inclined with respect to the photoelectric conversion substrate, the X-ray image taken between the X-ray grid and the switching element may not be obtained. Moiré occurs.
[0012]
In particular, in an X-ray detector having a structure including a scintillator layer with pixel separation, a similar phenomenon occurs not only between the X-ray grid and the switching element but also between the scintillator layer and the X-ray grid for each pixel. Therefore, the degree of the moire is remarkably exhibited.
[0013]
These phenomena occur not only for X-rays but also for various types of radiation.
[0014]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a radiation detector capable of suppressing occurrence of moire and improving resolution. is there.
[0015]
[Means for Solving the Problems]
The radiation detector according to the aspect of the present invention includes:
A photoelectric conversion substrate in which a plurality of pixel-based photoelectric conversion elements are arranged,
A scintillator layer disposed on the photoelectric conversion substrate and generating fluorescence when excited by radiation,
A partition portion formed on the photoelectric conversion substrate and partitioning the scintillator layer in pixel units;
With
The partitioning portion is disposed so as to surround at least a side surface of the scintillator layer, and a side reflection film that reflects fluorescence toward the inside of the scintillator layer, and radiation that is disposed so as to surround an outer surface of the side reflection film and absorbs radiation. And a grid.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a radiation detector according to an embodiment of the present invention will be described with reference to the drawings.
[0017]
Although the present invention is applicable to various types of radiation, the following embodiment will be described with reference to a typical X-ray case of radiation as an example. Therefore, by replacing “X-ray” in the embodiment with “radiation”, the present invention can be applied to other radiations targeted by the present invention.
[0018]
As shown in FIG. 1, an X-ray detector 1 that detects an X-ray and outputs an electric signal corresponding to the intensity distribution of the X-ray has an active matrix type photoelectric conversion substrate 11 having a plurality of pixels. I have. The photoelectric conversion substrates 11 are two-dimensionally arranged in a matrix at a predetermined pitch L in a row direction (for example, a horizontal direction in the drawing) and a column direction (for example, a vertical direction in the drawing) on an insulating substrate such as glass. A plurality of pixels 12 having the same structure. In the example shown in FIG. 1, nine pixel units (12a to 12i) are illustrated.
[0019]
Each of the pixels 12 (a to i) includes a photodiode 13 functioning as a photoelectric conversion element that converts the signal charge into incident signal light intensity, a thin film transistor (hereinafter, referred to as a TFT) 14 functioning as a switching element, and a signal charge. It is composed of a storage capacitor 15 functioning as a charge storage unit for storing.
[0020]
Each TFT 14 has a gate electrode G, a source electrode S, and a drain electrode D. The drain electrode D is electrically connected to, for example, the photodiode 13 and the storage capacitor 15.
[0021]
A control circuit 16 is provided outside the photoelectric conversion substrate 11. The control circuit 16 controls the operation state of the TFT 14, for example, on / off. The control circuit 16 is connected to a plurality of control lines 17 extending in the row direction. In the example shown in FIG. 1, first to fourth four control lines 171 to 174 are provided. Each control line 17 is connected to a gate electrode G of each TFT 14 constituting the pixels 12 in the same row. For example, the first control line 171 is connected to the gate electrode G of each TFT 14 forming the pixels 12a to 12c.
[0022]
A plurality of data lines 18 are provided in the column direction. In the example shown in FIG. 1, first to fourth four data lines 181 to 184 are provided. Each data line 18 is connected to the source electrode S of each TFT 14 constituting the pixels 12 in the same column. For example, the first data line 181 is connected to the source electrode S of each TFT 14 forming the pixels 12a, 12d, and 12g.
[0023]
Each data line 17 is connected to a corresponding charge amplifier 19. Each charge amplifier 19 is composed of, for example, an operational amplifier. The data line 18 is connected to one input terminal a1, and the other input terminal a2 is grounded. A capacitor C is connected between one input terminal a1 and the output terminal b, and has an integrating function. Further, a switch S is connected in parallel with the capacitor C. For example, the switch S is closed to discharge the charge remaining in the capacitor C.
[0024]
Each charge amplifier 19 is connected to a parallel / serial converter 20 that converts a plurality of electric signals input in parallel into serial signals. The parallel / serial converter 20 is connected to an analog-digital converter 21 that converts an analog signal into a digital signal.
[0025]
(1st Embodiment)
Next, a structure of a pixel unit of the X-ray detector according to the first embodiment will be described with reference to FIG. In FIG. 2, one pixel portion is extracted and shown, and portions corresponding to FIG. 1 are denoted by the same reference numerals, and a duplicate description is partially omitted.
[0026]
The photoelectric conversion substrate 11 includes a TFT 14 and a storage capacitor 15 formed on an insulating substrate 31 such as glass.
[0027]
The TFT 14 has three electrical connections, that is, a gate electrode G, a source electrode S, and a drain electrode D. The gate electrode G is formed on the insulating substrate 31. The gate electrode G is covered with the insulating film 32. The gate electrode G is connected to a common control line 17 together with the gate electrodes G of the other TFTs 14 located on the same row.
[0028]
The source electrode S is in contact with a semi-insulating film 33 formed on the insulating film 32. The source electrode S is connected to a common data line 18 together with the source electrodes S of other TFTs 14 located in the same column. The drain electrode D is in contact with the semi-insulating film 33. The drain electrode D is connected to the photodiode 13 and the storage capacitor 15.
[0029]
The storage capacitor 15 includes a lower electrode 34 formed on the insulating substrate 31, an upper electrode 35 provided to face the lower electrode 34 with the insulating film 32 interposed therebetween, and the like. The upper electrode 35 is electrically connected to the drain electrode D of the TFT 14.
[0030]
A first insulating layer 361 is provided above the TFT 14 and the storage capacitor 15. The photodiode 13 is formed on the first insulating layer 361. On the first insulating layer 361 around the photodiode 13, a second insulating layer 362 is provided. The second insulating layer 362 is formed in a frame shape so as to surround the photodiode 13 having a substantially rectangular shape.
[0031]
The photodiode 13 is formed of an a-Si pn diode, a PIN diode, or the like. The photodiode 13 includes a first electrode 131 formed on the first insulating layer 361, a second electrode 132 disposed to face the first electrode 131, and the like.
[0032]
The first electrode 131 is connected to the drain electrode D of the TFT 14 via a through hole 37 formed in a part of the first insulating layer 361. The second electrode 132 is formed, for example, by forming a transparent conductive film such as ITO by a sputtering method. A bias voltage is applied between the first electrode 131 and the second electrode 132.
[0033]
On the photoelectric conversion substrate 11 having the above-described structure, a scintillator layer 39 that converts X-rays incident from the outside into visible light (that is, emits fluorescence when excited by the X-rays) is disposed. Further, on the photoelectric conversion substrate 11, a partitioning section 38 for partitioning the scintillator layer 39 in pixel units is formed.
[0034]
That is, as shown in FIG. 2, the scintillator layer 39 is disposed on the photodiode 13 and the second insulating layer 362 on the photoelectric conversion substrate 11. The scintillator layer 39 is made of, for example, phosphor particles having substantially the same average particle size, for example, GOS (Gd ₂ O ₂ S: Tb, PR ⁺³ , CE ⁺³ , F). The particle size of the phosphor particles constituting the scintillator layer 39 is confirmed by, for example, photographing a cross section of the scintillator layer 39 with a scanning electron microscope.
[0035]
This scintillator layer 39 is formed, for example, by the following method.
First, a scintillator-containing coating layer is formed by applying a liquid scintillator material on a photoelectric conversion substrate 11 having a plurality of photodiodes 13 arranged in a matrix. This scintillator material is formed, for example, by using the above-mentioned powder of Gd ₂ O ₂ S: Tb as a phosphor particle that absorbs and emits X-rays using a resin binder and an organic solvent. This scintillator material is applied by a coating method using a dispenser, ink jet, spray, or the like.
[0036]
Thereafter, the organic solvent is removed through a drying step of heating at 60 to 150 ° C., and the scintillator-containing coating layer is cured. As a result, a good scintillator layer 39 that does not cause peeling or cracking of the film is formed.
[0037]
The partitioning section 38 converts the X-rays 40 incident on the scintillator layer 39 from above into fluorescent light 41 in the scintillator layer 39, and prevents the fluorescent light 41 from interfering with the area of the photodiode 13 of the adjacent pixel 12. Are formed along the boundaries that separate
[0038]
The partition 38 includes a side reflection film 421 and an X-ray grid 422.
[0039]
The side reflection film 421 is disposed so as to surround at least the entire side surface of the scintillator layer 39 for one pixel 12. The side reflection film 421 reflects the fluorescence 411 scattered outward toward the adjacent pixel 12 from the fluorescence 41 generated in the scintillator layer 39 toward the inside of the scintillator layer 39.
[0040]
The X-ray grid 422 is arranged so as to surround the outer surface of the side reflection film 421. That is, the X-ray grid 422 is arranged between the side reflection films 421 of the adjacent pixels 12. The X-ray grid 422 absorbs scattered X-rays scattered outward toward the adjacent pixel 12 among the X-rays incident on the pixel 12.
[0041]
The partition 38 is formed, for example, by the following method.
First, as shown in FIG. 3A, a first groove 38A having a first width W1 is formed in the scintillator layer 39. The first groove 38A may be formed to a depth reaching the second insulating layer 362 of the photoelectric conversion substrate 11, or the scintillator layer 39 may remain between the first groove 38A and the photoelectric conversion substrate 11. It may be formed at a depth.
[0042]
Thereafter, as shown in FIG. 3B, the inside of the first groove 38A is filled with a reflective material having light reflectivity, thereby forming the side surface reflective film 421. As the reflective material forming the side surface reflective film 421, particles having high refraction characteristics, for example, TiO ₂ , or X-ray light emitting phosphor particles, for example, Gd ₂ O ₂ S: Tb are used.
[0043]
Thereafter, as shown in FIG. 3C, a second groove 38B having a second width W2 is formed in the side reflection film 421. The second width W2 is set smaller than the first width W1. The second groove 38B is formed substantially at the center of the side reflection film 421, and may be formed at a depth reaching the second insulating layer 362 of the photoelectric conversion substrate 11, or the first groove 38A and the photoelectric conversion substrate may be formed. 11 may be formed to such a depth that the scintillator layer 39 remains. The above-described first groove portion 38A and second groove portion 38B can be formed by using a dicer or a YAG third-harmonic ultraviolet laser.
[0044]
Thereafter, as shown in FIG. 3D, an X-ray grid 422 is formed by filling the inside of the second groove 38B with a high X-ray absorber. As the high X-ray absorber constituting the X-ray grid 422, a metal material such as aluminum (Al) or lead (Pb) is used.
[0045]
Here, the high X-ray absorber refers to a material having a half-value layer (thickness that reduces the energy of X-rays when the X-rays are incident on a certain substance) and has an X-ray energy of 60 keV and 0.5 mm or less. And The X-ray energy of 60 keV is a general value of the energy of X-rays used for medical purposes. Since the thickness of the light emitting layer is 0.5 mm or more, the thickness of the X-ray grid is necessarily 0.5 mm or more. It becomes. Therefore, in order to reduce the influence of scattered X-rays, that is, to efficiently absorb scattered X-rays, an X-ray absorber having at least a half-value layer of 0.5 mm or less is required.
[0046]
According to the above-described method of forming the partition 38, the X-ray grid 422 is formed by filling a metal powder as a high X-ray absorber between the side reflection films 421 of the adjacent pixels 12; An X-ray grid 422 may be formed by arranging a plate-like metal material between 421. Further, the X-ray grid 422 may be formed by a coating of a metal material surrounding the outer surface of the side reflection film 421.
[0047]
According to the X-ray detector according to the first embodiment described above, the scintillator layer 39 is partitioned into pixel units by the partition unit 38. The partition 38 includes an X-ray grid 422 that absorbs X-rays. For this reason, penetration of the scattered X-rays into the scintillator layer 39 of the adjacent pixel 12 can be suppressed. Further, since the X-ray grid 422 is formed between the TFTs 14 as switching elements, it is possible to suppress the occurrence of moire due to the overlap between the X-ray grid 422 and the TFT 14.
[0048]
Further, when the fluorescent light 41 emitted in the scintillator layer 39 reaches the partition 38, the fluorescent light 41 is absorbed by the X-ray grid 422 that absorbs X-rays. For this reason, the luminance of each pixel 12 decreases. For this reason, the partition 38 having the above-described structure includes the side reflection film 421 so as to surround the side of the scintillator layer 39 for each pixel 12.
[0049]
In such a partition 38, the fluorescence 41 that has reached the partition 38 is not absorbed and is reflected toward the inside of the scintillator layer 39. For this reason, the brightness of each pixel 12 can be improved as compared with the structure in which the partitioning section 38 is configured only by the X-ray grid 422.
[0050]
In addition, a part of the fluorescent light 41 which is not reflected by the side surface reflection film 421 and is transmitted toward the adjacent pixel 12 is absorbed by the X-ray grid 422. Therefore, the pixels 12 can be completely separated. Therefore, the resolution characteristics can be improved as compared with the structure in which the partitioning section 38 is constituted only by the side reflection film 421.
[0051]
(2nd Embodiment)
Next, a structure of a pixel unit of the X-ray detector according to the second embodiment will be described with reference to FIG. In FIG. 4, one pixel portion is extracted and shown, and portions corresponding to FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is partially omitted.
[0052]
The X-ray detector according to the second embodiment includes an upper reflection film 43 disposed so as to cover the upper surface of the scintillator layer 39. That is, the fluorescent light 41 emitted inside the scintillator layer 39 radiates in a spherical shape. Therefore, in addition to the fluorescent light that travels downward toward the photodiode 13, the fluorescent light 412 that travels upward toward the X-ray source that emits the X-rays 40 exists. The fluorescent light 412 is lost without being incident on the photodiode 13, and thus becomes a factor for lowering the luminance of the pixel 12.
[0053]
Thus, as shown in FIG. 4, the fluorescent light 412 is reflected toward the inside of the scintillator layer 39 by arranging the upper surface reflection film 43 over the upper surfaces of the scintillator layer 39 and the partition 38. Thus, the fluorescent light 412 travels downward toward the photodiode 13 and contributes to the luminance of the pixel 12.
[0054]
The upper reflective film 43 is made of a reflective material having light reflectivity, and is made of particles having high refraction characteristics, such as TiO ₂ .
[0055]
For example, after the step of forming the X-ray grid 422 shown in FIG. 3D, a reflective material having light reflectivity is arranged on the entire upper surfaces of the scintillator layer 39 and the partition 38. Formed by
[0056]
According to the X-ray detector according to the second embodiment described above, the same effects as those of the above-described first embodiment can be obtained, and the fluorescence 412 diffused toward the upper surface is directed toward the inside of the scintillator layer 39. Since the light can be reflected, the loss of the fluorescent light 41 can be reduced, and the luminance of each pixel 12 can be improved.
[0057]
(Third embodiment)
Next, the structure of a pixel unit of the X-ray detector according to the third embodiment will be described with reference to FIG. In FIG. 5, one pixel portion is extracted and shown, and portions corresponding to FIG. 1 and FIG. 4 are denoted by the same reference numerals, and redundant description is partially omitted.
[0058]
In the X-ray detector according to the third embodiment, the partition 38 has a height that protrudes from the upper surface of the scintillator layer 38. That is, the partition 38, particularly the X-ray grid 422, protrudes above the upper surface of the scintillator layer 39 by a height t as shown in FIG. As the height t is larger, the penetration of scattered X-rays into the scintillator layer 39 can be suppressed.
[0059]
The X-ray detector includes an upper reflecting film 43 disposed so as to cover the upper surface of the scintillator layer 39. The upper reflecting film 43 is disposed only on the upper surface of the scintillator layer 39 and is provided independently for each pixel 12.
[0060]
Such a structure is formed, for example, as follows. That is, at a stage before forming the first groove portion 38A shown in FIG. 3A (that is, a stage before separating the scintillator layer 39 into pixels), after forming the scintillator layer 39 on the photoelectric conversion substrate 11, By disposing a reflective material having light reflectivity on the entire upper surface of the scintillator layer 39, the upper reflective film 43 is formed. Thereafter, as shown in FIG. 3A, pixels are separated by forming a first groove 38A in the scintillator layer 39 and the upper reflective film 43, and further, a side reflective film 421 and an X-ray grid 422 are sequentially formed. I do.
[0061]
According to the X-ray detector according to the third embodiment described above, the same effect as that of the above-described second embodiment can be obtained, and further, the penetration of the scattered X-rays into the scintillator layer 39 can be suppressed. Therefore, the contrast of the captured X-ray image can be improved.
[0062]
(Fourth embodiment)
Next, the structure of a pixel unit of the X-ray detector according to the fourth embodiment will be described with reference to FIG. In FIG. 6, one pixel portion is extracted and shown, and portions corresponding to FIGS. 1 and 5 are denoted by the same reference numerals, and a duplicate description is partially omitted.
[0063]
Also in the X-ray detector according to the fourth embodiment, similarly to the third embodiment, the partitioning portion 38 has a height t protruding from the upper surface of the scintillator layer 38, and the scattered X-rays We control invasion.
[0064]
The X-ray detector includes an upper reflecting film 43 disposed so as to cover the upper surface of the scintillator layer 39, and further includes a low X-ray absorbing layer 44 on the upper surface of the upper reflecting film 43. The upper reflective film 43 and the low X-ray absorbing layer 44 are arranged only on the upper surface of the scintillator layer 39 and are provided independently for each pixel 12.
[0065]
As the low X-ray absorption layer 44 applied in the fourth embodiment, a resin such as an acrylic resin or an epoxy resin, for example, a low X-ray absorber such as a glass is used. Here, since a low X-ray absorber is desired to have low absorption of X-rays, when the half-value layer is δ at an X-ray energy of 60 keV, it is larger than the thickness T of the low X-ray absorber. (Δ> T).
[0066]
In such a structure, for example, as described in the third embodiment, a reflective material having light reflectivity is arranged on the entire upper surface of the scintillator layer 39 before the first groove 38A is formed in the scintillator layer 39. After forming the upper surface reflection film 43 by performing the process, the low X-ray absorption layer 44 is formed by disposing the low X-ray absorber. Thereafter, as shown in FIG. 3A, pixels are separated by forming first grooves 38A in the scintillator layer 39, the upper reflecting film 43, and the low X-ray absorbing layer 44, and further, the side reflecting films are formed. 421 and an X-ray grid 422 are sequentially formed.
[0067]
According to the X-ray detector according to the fourth embodiment described above, compared to the X-ray detectors according to the first to third embodiments, the X-ray detector is less susceptible to scattered X-rays. Since 422 is formed between the TFTs 14 and between the scintillator layers 39 for each pixel 12, the occurrence of moire caused by the superposition of the X-ray grid 422 and the TFT 14 or the superposition of the scintillator layer 39 for each pixel 12 is prevented. Can be suppressed. In addition, resolution characteristics can be improved.
[0068]
Although common to the first to fourth embodiments described above, the X-rays 40 are provided by an X-ray source 51 provided at a distance from the center of the scintillator layer 39 to the upper surface, as shown in FIG. Radiated radially. For this reason, it is desirable that the partitioning section 38 for separating the pixels of the scintillator layer 39 be formed so as to be parallel to the traveling direction of the normal X-ray (straight wave) emitted from the X-ray source 51. With such a structure, the influence of scattered X-rays can be reduced by the X-ray grid 422 included in the partition 38.
[0069]
The present invention is not limited to the above embodiments, and various modifications and changes can be made at the stage of implementation without departing from the scope of the invention. In addition, the embodiments may be implemented in appropriate combinations as much as possible, and in that case, the effect of the combination is obtained.
[0070]
The X-ray detector according to the present invention has been described with respect to a configuration in which a plurality of pixels are arranged vertically and horizontally. However, at first glance, the ratio of the pixels vertically and horizontally is different (for example, when one of the pixels is one, etc.). It is also possible to apply to the X-ray detector comprised in the shape. In this case, the switching element can be implemented without using a TFT.
[0071]
【The invention's effect】
As described above, according to the present invention, it is possible to provide an X-ray detector capable of suppressing generation of moiré and improving resolution.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a circuit configuration of an X-ray detector according to one embodiment of the present invention.
FIG. 2 is a sectional view schematically showing a structure of one pixel portion of the X-ray detector according to the first embodiment.
FIGS. 3A to 3D are views for explaining a forming process for forming a partition of the X-ray detector according to the first embodiment.
FIG. 4 is a sectional view schematically showing a structure of one pixel portion of an X-ray detector according to a second embodiment.
FIG. 5 is a cross-sectional view schematically showing a structure of one pixel portion of an X-ray detector according to a third embodiment.
FIG. 6 is a sectional view schematically showing a structure of one pixel portion of an X-ray detector according to a fourth embodiment.
FIG. 7 is a diagram for explaining a structure of a partition formed in parallel with a traveling direction of emitted X-rays.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... X-ray detector 11 ... photoelectric conversion substrate 12 ... pixel 13 ... photodiode 14 ... thin film transistor (TFT)
15. Storage capacitor 38 Partition 39 Scintillator layer 421 Side reflection film 422 X-ray grid 43 Top reflection film 44 Low X-ray absorption layer

Claims (8)

A photoelectric conversion substrate in which a plurality of pixel-based photoelectric conversion elements are arranged,
A scintillator layer disposed on the photoelectric conversion substrate and generating fluorescence when excited by radiation,
A partition portion formed on the photoelectric conversion substrate and partitioning the scintillator layer in pixel units;
With
The partitioning portion is disposed so as to surround at least a side surface of the scintillator layer, and a side reflection film that reflects fluorescence toward the inside of the scintillator layer, and radiation that is disposed so as to surround an outer surface of the side reflection film and absorbs radiation. A radiation detector, comprising: a grid; The radiation detector according to claim 1, further comprising an upper surface reflection film that is arranged to cover an upper surface of the scintillator layer and reflects fluorescence toward the inside of the scintillator layer. The radiation detector according to claim 1, wherein the partition has a height protruding from an upper surface of the scintillator layer. 4. The radiation detector according to claim 3, further comprising a top reflection film disposed so as to cover only an upper surface of the scintillator layer and reflecting fluorescence toward the inside of the scintillator layer. 5. The radiation detector according to claim 4, wherein a low radiation absorption layer is provided on an upper surface of the upper reflection film. The radiation detector according to claim 1, wherein the radiation grid is formed by filling a powder of a heavy metal material between the side reflection films of the adjacent pixels. The radiation detector according to claim 1, wherein the radiation grid is formed by arranging a plate-like heavy metal material between the side reflection films of adjacent pixels. The radiation detector according to claim 1, wherein the radiation grid is formed of a coating of a heavy metal material surrounding an outer surface of the side reflection film.

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