JP7490951B2 - Radiation detection panel and radiation image detector - Google Patents

Description

The present invention relates to a radiation detection panel and a radiation image detector.

Conventionally, a radiation image detector (also called a Flat Panel Detector (FPD)) has been developed that uses a radiation detection panel in which incident radiation is converted into light such as visible light by a scintillator and the converted light is detected by a plurality of photoelectric conversion elements such as photodiodes arranged two-dimensionally on a substrate. The radiation image detector is configured to convert incident light into electric charges by the photoelectric conversion elements and extract the generated electric charges to detect information carried by the radiation irradiated through the subject as an electric signal.
As shown in FIG. 10 , a radiation detection panel has a configuration in which an element substrate 102 on which photoelectric conversion elements 101 are arranged and a scintillator substrate 104 on which a scintillator 103 is formed are laminated, and a sealing material 105 is arranged so as to surround the side surfaces of the photoelectric conversion elements 101 and the scintillator 103 (for example, see Patent Document 1).

JP 2011-174830 A

However, due to the placement of the sealing material, the radiation detection panel with the above configuration cannot place the scintillator all the way to the edge of the radiation detection panel, making it difficult to perform diagnosis at the edge of the panel.

The objective of the present invention is to provide a radiation detection panel and a radiation image detector that can expand the diagnostic area to the ends of the radiation detection panel.

In order to solve the above problems, the radiation detection panel of the present invention comprises:
an element substrate having a plurality of photoelectric conversion elements arranged on one surface;
a scintillator that converts radiation into light and irradiates the photoelectric conversion element with the light;
Equipped with
the scintillator is laminated on the element substrate so as to face the photoelectric conversion element;
a moisture-proof layer covering all sides of the scintillator and at least one side of the element substrate ;
The moisture-proof layer is provided only on the side surfaces of the scintillator and the element substrate .
The radiation detection panel of the present invention further comprises:
an element substrate having a plurality of photoelectric conversion elements arranged on one surface;
a scintillator that converts radiation into light and irradiates the photoelectric conversion element with the light;
Equipped with
the scintillator is laminated on the element substrate so as to face the photoelectric conversion element;
a moisture-proof layer covering all sides of the scintillator and at least one side of the element substrate;
A protective layer is provided on the side surface of the scintillator,
the moisture-proof layer is provided on all sides of the scintillator via the protective layer,
The protective layer is characterized in that it is provided only on the side surfaces of the scintillator.
The radiation detection panel of the present invention further comprises:
an element substrate having a plurality of photoelectric conversion elements arranged on one surface;
a scintillator that converts radiation into light and irradiates the photoelectric conversion element with the light;
Equipped with
the scintillator is laminated on the element substrate so as to face the photoelectric conversion element;
a moisture-proof layer covering all sides of the scintillator and at least one side of the element substrate;
A protective layer is provided on the side surface of the scintillator,
the moisture-proof layer is provided on all sides of the scintillator via the protective layer,
The protective layer is characterized in that it is made of one or a combination of a metal oxide, a metal nitride, or a metal oxynitride.

The radiation image detector of the present invention further comprises:
The present invention is characterized by comprising the above-mentioned radiation detection panel.

The present invention makes it possible to expand the diagnostic area to the edge of the radiation detection panel.

FIG. 2 is an external perspective view of the radiation image detector. 2 is a cross-sectional view taken along line AA in FIG. 1. 2 is a plan view showing a configuration of a surface of an element substrate included in the radiation detection panel. FIG. 4 is an enlarged view showing the configuration of a photoelectric conversion element, a thin film transistor, and the like formed in a small region on the element substrate of FIG. 3. 1A and 1B are diagrams illustrating an element substrate on which a COF or a PCB substrate is attached. FIG. 2 is an enlarged schematic diagram illustrating the configuration of a scintillator having a columnar phosphor structure and its attachment to a scintillator substrate. FIG. 2 is a perspective view of a radiation detection panel. 8 is a cross-sectional view taken along line BB in FIG. 7. FIG. 8 is a cross-sectional view showing a modified example of the radiation detection panel of FIG. 7 . FIG. 1 is a diagram for explaining a conventional configuration.

Below, an embodiment of the present invention will be described in detail with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples.

[Radiation detection panel and radiation image detector]
First, the configurations of the radiation detection panel 3 and the radiation image detector 1 according to this embodiment will be described.

In the following, as shown in Figures 1 and 2, the relative positional relationship of each component in the radiation image detector 1 and radiation detection panel 3, particularly the vertical relationship, will be described based on the positional relationship when the surface X side of the housing 2 of the radiation image detector 1 on which radiation is incident faces upward, and the surface Y side of the housing 2 opposite the surface X on which radiation is incident faces downward.

FIG. 1 is an external perspective view of a radiation image detector 1 according to this embodiment, and FIG. 2 is a cross-sectional view taken along line AA in FIG.
As shown in FIGS. 1 and 2, the radiation image detector 1 has a radiation detection panel 3 housed in a housing 2 .

The housing 2 is made of materials such as carbon plate, plastic, etc. Although Fig. 1 and Fig. 2 show a so-called lunchbox type housing 2 formed of a frame plate 51 and a back plate 52, it is also possible for the housing 2 to be a so-called monocoque type formed in a rectangular cylindrical shape.
Further, on the side portion of the housing 2, an indicator 53 constituted by an LED or the like, a cover 54, a terminal 55 for connection to an external device, a power switch 56, etc. are arranged.

As shown in FIG. 2, a radiation detection panel 3 including an element substrate 4, a scintillator substrate 5, a scintillator 6, etc. is disposed inside the housing 2.
A base 7 is disposed below the radiation detection panel 3 via a thin lead plate or the like (not shown). A PCB board 9 on which various electronic components 8 such as a CPU (Central Processing Unit) and a RAM (Random Access Memory) are mounted, buffer members 10, and the like are attached to the base 7.

In this embodiment, the element substrate 4 is made of a glass substrate that transmits light such as radiation and ultraviolet light. However, the element substrate 4 can also be made of a resin plate or film made of, for example, PET (polyethylene terephthalate), polyethylene naphthalate, polybutylene naphthalate, polycarbonate, syndiotactic polystyrene, polyetherimide, polyarylate, polysulfone, polyethersulfone, polyimide, or the like. The present invention is not limited to these.
3 is a plan view showing the configuration of the surface of the element substrate 4. On the surface 4a of the element substrate 4 (i.e., the surface facing the scintillator 6 (see FIG. 2)), a plurality of scanning lines 11 and a plurality of signal lines 12 are arranged so as to intersect with each other. In addition, a plurality of bias lines 13 are arranged in parallel with the plurality of signal lines 12, and in this embodiment, each bias line 13 is bound by a single connection wire 14 at one end on the element substrate 4.

A photoelectric conversion element 15 is provided in each small region R defined by a plurality of scanning lines 11 and a plurality of signal lines 12 on the surface 4a of the element substrate 4. Thus, in this embodiment, the element substrate 4 has a plurality of photoelectric conversion elements 15 arranged two-dimensionally on its surface 4a. Each photoelectric conversion element 15 is connected to a bias line 13, and in this embodiment, a bias voltage is applied to the photoelectric conversion elements 15 from a bias power supply (not shown) via the bias line 13.

In this embodiment, a photodiode is used as the photoelectric conversion element 15. When irradiated with light output from the scintillator 6 that has been irradiated with radiation, the photodiode absorbs light energy and generates electron-hole pairs inside, thereby converting the light energy into electric charges.
Also, as shown in the enlarged view of Figure 4, each small region R has one thin film transistor (hereinafter referred to as "TFT") 16 for each photoelectric conversion element 15, and the source electrode 16s of the TFT 16 is connected to one electrode of the photoelectric conversion element 15, the drain electrode 16d is connected to the signal line 12, and the gate electrode 16g is connected to the scanning line 11.

In the radiation detection panel 3 of this embodiment, as shown in FIG. 3, the ends of the scanning lines 11, signal lines 12, and connection lines 14 are each connected to input/output terminals (also called pads) 18 on the surface 4a of the element substrate 4 configured as described above.

As shown in FIG. 5, a COF (Chip On Film) 19 is pressure-bonded to each input/output terminal 18 via an anisotropic conductive adhesive material 20 such as an anisotropic conductive film or an anisotropic conductive paste. The COF 19 is routed to the rear surface 4b of the element substrate 4, and is pressure-bonded to the PCB substrate 9 and the COF 19 on the rear surface 4b.

As shown in FIG. 5, in the portion of the surface 4a of the element substrate 4 where the multiple photoelectric conversion elements 15 etc. are formed, a planarization layer 21 is formed by applying a transparent resin or the like so as to cover the multiple photoelectric conversion elements 15 etc. in order to planarize the surface irregularities caused by the multiple photoelectric conversion elements 15 etc. and to serve as a base for the scintillator 6 (not shown in FIG. 5) when it is arranged opposite the photoelectric conversion elements 15 etc.

In this embodiment, the planarization layer 21 is formed of a transparent acrylic photosensitive resin that transmits the light output from the phosphor 6a of the scintillator 6. Note that in FIG. 5, the scintillator 6 and electronic components 8 are not shown.

The scintillator 6 (see FIG. 2) converts incident radiation into light of a different wavelength, and is mainly composed of a phosphor. Specifically, in this embodiment, the scintillator 6 is one that outputs electromagnetic waves with wavelengths of 300 nm to 800 nm, i.e., light ranging from ultraviolet light to infrared light with a focus on visible light, when radiation such as X-rays is incident. As the phosphor, for example, one in which a luminescent center substance is activated within a host material such as CsI:Tl is preferably used.

As shown in the enlarged view of FIG. 6, the scintillator 6 is formed by growing phosphor 6a, for example, by vapor phase growth, on a support film 6b made of various polymeric materials such as cellulose acetate film, polyester film, and polyethylene terephthalate film, and is composed of columnar crystals of phosphor 6a. As the vapor phase growth method, a deposition method or a sputtering method is preferably used.

In either method, the phosphor 6a can be vapor-grown as independent, elongated columnar crystals on the support film 6b. Each columnar crystal of the phosphor 6a is thick near the support film 6b and becomes thinner toward the tip (the lower end in FIG. 6) Pa, which grows to form an acute-angled, roughly conical shape.

In this embodiment, the scintillator 6 in which the phosphor 6a is formed as columnar crystals in this manner has its support film 6b attached to the surface 5a so that the acute-angled tips Pa of the columnar crystals of the phosphor 6a face downward, i.e., toward the multiple photoelectric conversion elements 15 of the element substrate 4 described above. In this way, the scintillator 6 is supported by the scintillator substrate 5.

In some cases, the scintillator 6 is formed with the entire columnar crystals of the phosphor 6a covered with a film or the like. In that case, the thickness of the film is made uniform, and when the tip Pa of the phosphor 6a abuts against the surface of the planarization layer 21, the tip Pa of the phosphor 6a abuts against the surface of the planarization layer 21 via the film.

In this embodiment, the scintillator substrate 5 is made of a glass substrate. However, the scintillator substrate 5 can also be made of other materials such as a resin plate or a resin film, such as PET (polyethylene terephthalate), polyethylene naphthalate, polybutylene naphthalate, polycarbonate, syndiotactic polystyrene, polyetherimide, polyarylate, polysulfone, polyethersulfone, or polyimide. The present invention is not limited to these.

Figure 7 is a perspective view of the radiation detection panel 3 in Figure 2, and Figure 8 is a cross-sectional view taken along line B-B in Figure 7. Note that the scintillator substrate 5 is omitted in Figure 7. Also, in Figure 8, the relative sizes and thicknesses of the components of the radiation detection panel 3, the spacing between the components, and the like do not necessarily reflect the structure of the actual radiation detection panel 3.

As described above, the radiation detection panel 3 is formed by stacking the element substrate 4 and the scintillator substrate 5 so that the photoelectric conversion elements 15 and the scintillator 6 face each other. Specifically, the scintillator substrate 5 is formed by arranging the acute-angled tip Pa of the phosphor 6a of the scintillator 6 so that it faces the multiple photoelectric conversion elements 15 and the planarization layer 21.

As shown in FIG. 7 , a moisture-proof layer 22 is disposed so as to cover all side surfaces (all peripheries of the side surfaces) of the scintillator substrate 5 and the scintillator 6 and at least one side surface of the element substrate 4 .
Specifically, the element substrate 4, the scintillator substrate 5, and the scintillator 6 are rectangular, and are stacked such that at least one side (one side end) in a plan view overlaps and is aligned. The side surfaces of the aligned side ends are flush, and the moisture-proof layer 22 is provided on this side. This configuration can be realized, for example, by stacking the element substrate 4 and the scintillator substrate 5 by butting them against a predetermined reference plane, which facilitates manufacturing and increases the durability of the configuration.
FIG. 7 shows an example in which two sides of a rectangular element substrate 4, a scintillator substrate 5, and a scintillator 6 are aligned and overlap each other.

As described above, it is most preferable that the element substrate 4, the scintillator substrate 5, and the scintillator 6 are stacked so that the ends of at least one side (one end) in plan view are overlapped and aligned (side surfaces are flush). However, even if the element substrate 4 protrudes from the scintillator 6 at this one end when at least one end is overlapped in plan view, it is a preferable embodiment from the viewpoint of ensuring the durability of the structure, etc., as long as the protruding width (tolerance) is within 2% of the width of the element substrate 4. Furthermore, the durability effect is further improved by making the protruding width within 1%, 0.5%, and 0.25% of the width of the element substrate 4.

Moreover, the moisture-proof layer 22 is preferably provided only on the side surfaces of the element substrate 4, the scintillator substrate 5, and the scintillator 6. In other words, it is preferable that the moisture-proof layer 22 does not extend onto the surfaces of the element substrate 4 and the scintillator substrate 5.
This is to prevent unintended steps or the like from occurring on the surfaces of the moisture-proof layer 22 when the radiation detection panel 3 is housed in the housing 2, which would otherwise cause noise or other effects in the radiation image.

The moisture-proof layer 22 is provided in a film shape, and from the viewpoint of providing sealing with high moisture resistance, an adhesive using an epoxy resin, an adhesive using a silicone resin, etc. is preferably used. The thickness of the moisture-proof film 22 depends on the type of resin, but for example, if it is an epoxy resin, it is preferably 0.1 mm or more.
Here, the moisture-proof layer 22 may be a thermosetting adhesive that hardens when heated, or a photosetting adhesive that hardens when irradiated with light.
As the thermosetting adhesive, for example, an adhesive using a thermosetting resin or an adhesive to which a curing accelerator or the like is further added can be used.
As the photocurable adhesive, an ultraviolet-curable resin containing a photoinitiator, a photopolymerizable compound, or the like can be used.

Furthermore, depending on the material of the moisture-proof layer 22, adverse effects may occur due to contact with the scintillator 6 during the curing process.
Therefore, as shown in FIG. 9, it is also preferable to provide a protective layer 23 on the side surface of the scintillator 6, and to provide the moisture-proof layer 22 on the side surface of the scintillator 6 with the protective layer 23 interposed therebetween.
The protective layer 23 may be one or a combination of metal oxides, metal nitrides, or metal oxynitrides such as SiO2, Al2O3, TiO2, SiN, AlN, and TiN. The moisture-proof layer 22 may be disposed after the film is formed on the side surface of the scintillator 6 by sputtering or the like, or the moisture-proof layer 22 may be disposed on the side surface of the scintillator. The thickness of the protective layer 23 depends on the material to be disposed, but in the case of a SiO2 film formed by sputtering, for example, the thickness is preferably 40 nm or more. In addition, by using a material with high moisture permeability for the protective layer 23, the thickness of the moisture-proof layer 22 can be reduced. In the case of the 40 nm SiO2 film formed by sputtering described above, the thickness of the moisture-proof layer 22 is preferably 50 μm or more.
Similarly to the moisture-proof layer 22, in order to prevent noise from occurring in radiation images, the protective layer 23 is preferably formed only on the side surfaces of the scintillator 6 and does not extend to the upper or lower surfaces of the scintillator 6.
By providing such a protective layer 23, it is possible to eliminate any adverse effect that may occur on the scintillator 6 during the hardening process of the moisture-proof layer 22. Furthermore, the durability of the structure can be improved.

[effect]
As described above, according to the present embodiment, the radiation detection panel 3 comprises an element substrate 4 having a plurality of photoelectric conversion elements 15 arranged on one surface (front surface 4 a) thereof, and a scintillator 6 that converts radiation into light and irradiates the photoelectric conversion elements 15 with the light. The scintillator 6 is layered on the element substrate 4 so as to face the photoelectric conversion elements 15, and a moisture-proof layer 22 is provided that covers all side surfaces of the scintillator 6 and at least one side surface of the element substrate 4.
This makes it possible to expand the diagnostic area to the ends of the radiation detection panel 3. This can be advantageously used in, for example, mammography.

Furthermore, according to this embodiment, the element substrate 4 and the scintillator 6 are stacked and arranged with at least one end aligned when viewed in a plan view, the side surface of the one end is flush, and the moisture-proof layer 22 is provided on the side surface of the one end.
Therefore, it is possible to extend the diagnostic area to at least one side end of the radiation detection panel 3, and the manufacturing process is easy and the durability of the structure can be improved.

Furthermore, according to this embodiment, the moisture-proof layer 22 is provided only on the side surfaces of the scintillator 6 and the element substrate 4 .
Therefore, when the radiation detection panel 3 is housed in the housing 2, unintended steps are unlikely to occur, and problems such as noise in a radiation image can be prevented.

According to this embodiment, the side end of the scintillator 6 is provided with a protective layer 23, and the moisture-proof layer 22 is provided on all side surfaces of the scintillator 6 via the protective layer 23. This protective layer 23 is provided only on the side surfaces of the scintillator 6.
Therefore, the protective layer 23 can eliminate adverse effects on the scintillator 6 that occur during the hardening process of the moisture-proof layer 22. Furthermore, the structure can improve durability.

[others]
It goes without saying that the present invention is not limited to the above-described embodiment and modified examples, and can be modified as appropriate.

For example, in the above embodiment, a configuration is illustrated in which two sides of the rectangular element substrate 4 and scintillator 6 overlap and are sealed with the moisture-proof layer 22, but in the present invention, it is sufficient that at least one side is sealed with the moisture-proof layer 22. In other words, the moisture-proof layer 22 may be disposed on one or three sides of the rectangular element substrate 4 and scintillator 6, or may be disposed on the four sides that are the entire periphery.

In addition, in the above embodiment, a configuration in which the overlapping edges of the element substrate 4 and the scintillator substrate 5 are aligned, or a configuration in which the element substrate 4 and the scintillator substrate 5 overlap and the width by which the element substrate 4 protrudes beyond the scintillator 6 is within 2% of the width of the element substrate 4, is exemplified as a preferred embodiment, but the overlapping edges do not necessarily have to meet these conditions. In other words, even if the width by which the element substrate 4 protrudes beyond the scintillator 6 is greater than 2% when the element substrate 4 and the scintillator substrate 5 are overlapped, it is possible to provide the moisture-proof layer 22.

Reference Signs List 1 Radiation image detector 2 Housing 3 Radiation detection panel 4 Element substrate 4a Surface 5 Scintillator substrate 5a Surface 6 Scintillator 15 Photoelectric conversion element 22 Moisture-proof layer 23 Protective layer

Claims (7)

an element substrate having a plurality of photoelectric conversion elements arranged on one surface;
a scintillator that converts radiation into light and irradiates the photoelectric conversion element with the light;
Equipped with
the scintillator is laminated on the element substrate so as to face the photoelectric conversion element;
a moisture-proof layer covering all sides of the scintillator and at least one side of the element substrate;
2. A radiation detection panel comprising: a first insulating layer and a second insulating layer disposed on the first insulating layer; the scintillator and the element substrate overlap at least at one end portion in a plan view, and a tolerance for the element substrate protruding from the scintillator at the one end portion is within 2% of a width of the element substrate;
The radiation detection panel according to claim 1 , wherein the moisture-proof layer is provided on a side surface of the one end portion. The scintillator and the element substrate overlap each other at least at one end in a plan view, and a side surface of the one end is flush with each other,
3. The radiation detection panel according to claim 1, wherein the moisture-proof layer is provided on a side surface of the one end portion. A protective layer is provided on the side surface of the scintillator,
4. The radiation detection panel according to claim 1, wherein the moisture-proof layer is provided on all sides of the scintillator via the protective layer. The radiation detection panel according to claim 4, characterized in that the protective layer is provided only on the sides of the scintillator. an element substrate having a plurality of photoelectric conversion elements arranged on one surface;
a scintillator that converts radiation into light and irradiates the photoelectric conversion element with the light;
Equipped with
the scintillator is laminated on the element substrate so as to face the photoelectric conversion element;
a moisture-proof layer covering all sides of the scintillator and at least one side of the element substrate;
A protective layer is provided on the side surface of the scintillator,
the moisture-proof layer is provided on all sides of the scintillator via the protective layer,
A radiation detection panel, characterized in that the protective layer is provided only on the side surfaces of the scintillator. A radiation image detector comprising the radiation detection panel according to claim 1 .

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