JP6515958B2 - Radiation detector and method of manufacturing the same - Google Patents

Description

  The present technology relates to a radiation detector used for radiography such as medical treatment and nondestructive inspection and a method of manufacturing the same.

  The radiation detection apparatus described in Patent Document 1 includes a scintillator layer provided on an output substrate, and a partition structure provided in the scintillator layer for partitioning a plurality of pixels. The partition provided in the partition structure is formed to a predetermined height by repeating screen printing a plurality of times. A scintillator layer is formed by filling the phosphors in the partition walls (see, for example, the paragraph [0044] of the specification of Patent Document 1).

  Similar to Patent Document 1, the flat panel detector described in Patent Document 2 also includes a scintillator layer formed on a photoelectric conversion substrate, and a partition that divides the scintillator layer into pixels. This partition is formed by, for example, a screen printing method, a resist patterning method, or a photosensitive paste method (pattern exposure of partition shape of photosensitive paste, its development and baking treatment) (for example, the specification paragraph of Patent Document 2) [0047], [0052] to [0056], see [0064]).

  As disclosed in Patent Documents 1 and 2, since the partition wall is provided in the scintillator layer, light emitted from the phosphor is reflected by the partition wall and travels to the photodiode, so that the diffusion of light is suppressed and the resolution is improved. Do.

JP, 2011-21924, A JP 2002-202373 A

  In order to realize high sensitivity of radiation by a radiation detector in which a partition is provided in a scintillator layer, a further devise is required for the structure of the radiation detector.

  An object of the present technology is to provide a radiation detector which realizes high sensitivity of radiation and a method of manufacturing the same.

In order to achieve the above-mentioned object, a radiation detector concerning this art comprises a sensor substrate, a scintillator layer, and a partition.
The sensor substrate has a plurality of light receiving pixels.
The scintillator layer is provided on the sensor substrate.
The partition wall has a height of 300 μm to 800 μm and a width of 10 μm to 40 μm, and is provided to partition the scintillator layer for each pixel.

  The volume of the scintillator layer can be increased by providing the partition wall having a high height and a narrow width as described above. That is, radiation can be efficiently converted to visible light, and high sensitivity can be realized.

  The main component of the material of the partition may be an inorganic material.

  The material of the partition may contain 60% by weight or more and 100% by weight or less of glass. Thus, the partition wall can be formed with a high aspect ratio by photolithography using a photosensitive material containing glass.

  The inorganic material contained in the partition may contain at least one of glass and ceramic.

  The scintillator layer may include a phosphor material and a resin material. By including the resin material, it is possible to prevent the falling off of the phosphor material that may occur in the process of manufacturing the radiation detector by the cured resin.

  The scintillator layer may include a phosphor layer formed of the phosphor material and a mixed layer disposed between the phosphor layer and the sensor substrate and including both the phosphor material and the resin material. Good. Thus, by providing the mixed layer containing the resin material on the side closer to the sensor substrate than the phosphor layer, the mixed layer functions as a cap (cover) layer covering the phosphor layer by the dried or cured resin. Do. This makes it possible to prevent the dropout of the phosphor material that may occur in the manufacturing process of the radiation detector.

  The scintillator layer may include a phosphor material and a glass material. The glass material can also prevent the phosphor material from falling off during the manufacturing process of the radiation detector.

  The scintillator layer may include a phosphor material. In that case. The radiation detector may further include a cap layer provided between the scintillator layer, the partition wall, and the sensor substrate. By providing the cap layer, it is possible to prevent the phosphor material from falling off during the manufacturing process of the radiation detector.

  The cap layer may include at least a resin material. Alternatively, the cap layer may include a material in which the phosphor material and the resin material are mixed. By including the phosphor material in the cap layer, it is possible to prevent detachment of the phosphor material in the process of manufacturing the radiation detector without lowering the brightness.

A method of manufacturing a radiation detector according to the present technology includes forming partition walls on a substrate by exposure processing of a photosensitive paste material using a photomask and development processing thereof.
By baking the substrate on which the partition is formed, the partition having a height of 300 μm to 800 μm and a width of 10 μm to 40 μm is formed.
After the firing, a scintillator material is filled in a region surrounded by the partition walls on the substrate.

The volume of the scintillator layer can be increased by forming the barrier ribs having a high height and a narrow width as described above by the exposure processing of the photosensitive paste material using a photomask and the development processing thereof. That is, radiation can be efficiently converted to visible light, and high sensitivity can be realized.
In addition, the above-mentioned "substrate" concerning this art may be a sensor substrate which has the above-mentioned a plurality of light receiving pixels, and may be a counter substrate which counters it.

  The photosensitive paste material may contain an inorganic material and an organic binder. By substantially removing the organic binder by the above-described baking, partition walls made of an inorganic material can be formed.

  The barrier ribs may be formed to correspond to a plurality of pixels. Then, the manufacturing method further includes the step of bonding the sensor substrate and the substrate together such that the scintillator layer composed of the scintillator material is disposed on the sensor substrate having the plurality of light-receivable pixels. You may

  The substrate may be an opposing substrate facing a sensor substrate having the plurality of light-receiving pixels. In that case, the barrier ribs are formed to correspond to a plurality of pixels. And the said manufacturing method may further comprise the process of bonding together the said sensor substrate and the said opposing board | substrate so that the scintillator layer comprised with the said scintillator material may be arrange | positioned on the said sensor substrate.

  The method may further include the step of applying or transferring a material containing at least a resin material on the scintillator layer formed by the filling of the scintillator material.

  In the applying step, a solution containing the resin material may be applied onto the scintillator layer. Alternatively, in the transfer step, a sheet material containing the resin material may be transferred onto the scintillator layer. Alternatively, in the applying step, a paste material containing a phosphor material and the resin material may be applied on the scintillator layer.

  The substrate may be a sensor substrate having a plurality of light-receiving pixels, in which case the partition is formed to correspond to the plurality of pixels. Also, in that case, the manufacturing method comprises the steps of: applying or transferring a material containing at least a resin material on the scintillator layer formed by filling the scintillator material on the sensor substrate; and applying or transferring the material The method may further include the step of bonding the sensor substrate and the opposite substrate such that the scintillator layer thus disposed is disposed on the opposite substrate.

  As described above, according to the present technology, high sensitivity of the radiation detector can be realized.

FIG. 1 shows a part of the cross-sectional structure of a radiation detector according to an embodiment of the present technology. FIG. 2 is a cross-sectional view taken along the line AA in FIG. FIG. 3 schematically shows an example of a pixel portion on a sensor substrate and a pixel drive circuit disposed in the peripheral region thereof. FIG. 4 shows an example of a circuit of the pixel PX driven by the pixel drive circuit shown in FIG. FIG. 5 is a flowchart showing a method of manufacturing a radiation detector according to the present embodiment. FIG. 6 is a graph showing the relationship between the width of a partition and the brightness (brightness ratio) obtained by a radiation detector having the partition having that width. FIG. 7 is a table showing the relationship of FIG. FIG. 8 is a graph showing the relationship between the height of the partition wall and the brightness (brightness ratio) obtained by the radiation detector having the partition wall with the height. FIG. 9 is a table showing the relationship of FIG. FIG. 10 shows a radiation detector according to Example 1 of another embodiment. FIG. 11 is a diagram for explaining a method of manufacturing the radiation detector shown in FIG. FIG. 12 is a flowchart showing a method of manufacturing the radiation detector shown in FIG. FIG. 13 is a diagram for explaining a method of manufacturing a radiation detector according to Example 2 of the other embodiment. FIG. 14 is a diagram for explaining a method of manufacturing a radiation detector according to Example 3 of the other embodiment. FIG. 15 is a diagram for explaining a method of manufacturing a radiation detector according to Example 4 of the other embodiment. FIG. 16 is a diagram for explaining a method of manufacturing a radiation detector according to Example 5 of the other embodiment. FIG. 17 is a flowchart showing a method of manufacturing the radiation detector shown in FIG.

  Hereinafter, embodiments of the present technology will be described with reference to the drawings.

  [Configuration of radiation detector]

  FIG. 1 shows a part of the cross-sectional structure of a radiation detector according to an embodiment of the present technology. FIG. 2 is a cross-sectional view taken along the line AA in FIG.

  The radiation detector 1 is a panel that converts radiation represented by α rays, β rays, γ rays, and X rays into visible light and receives the light, and reads image information based on the radiation as an electrical signal. , And other suitable non-destructive inspection X-ray imaging apparatus such as baggage inspection.

  The radiation detector 1 includes a sensor substrate 11, a scintillator layer 12 provided on the sensor substrate 11, partition walls 14 provided on the scintillator layer 12, and an opposing substrate (substrate) 13 provided on the scintillator layer 12. And The configuration of each part will be described in detail below.

(Sensor board)
In FIG. 1, the structure of the sensor substrate 11 is simplified and shown. The sensor substrate 11 has a pixel unit (a pixel unit 10 described later) including a plurality of light-receiving pixels PX. The sensor substrate 11 is configured such that a drive circuit for driving the pixel unit 10 is disposed in the peripheral region of the pixel unit 10. The pixel unit 10 includes, for each pixel, a switch element such as a TFT (Thin Film Transistor) (a transistor Tr described later) and a photodiode 16 as a photoelectric sensor as shown in FIG. Various known structures and arrangements can be applied to the structure and arrangement of these elements.

  The thickness of the sensor substrate 11 is preferably 50 to 1000 μm from the viewpoint of durability and weight reduction. The details (pixel circuit and cross-sectional structure) of the pixel section 10 in the sensor substrate 11 and the configuration of the peripheral circuit (pixel drive circuit) will be described later.

(Scintillator layer and partition wall)
The scintillator layer 12 is a layer composed of a radiation phosphor that emits fluorescence upon irradiation with radiation. The scintillator material which is the material of the scintillator layer 12 contains at least a phosphor material. As the phosphor material, it is desirable to use a material that absorbs radiation energy and has a high conversion efficiency to an electromagnetic wave having a wavelength of 300 nm to 800 nm (electromagnetic wave (light) ranging from ultraviolet light to infrared light centering on visible light). As will be described later in the description of the manufacturing method, the scintillator layer can be formed, for example, by applying a paste material containing phosphor particles containing Gd ₂ O ₂ S as a main component.

  Examples of such a phosphor material include CsI as a main agent, and Tl or Na as an activator (activator) for compensating for light emission efficiency and the like. The thickness of the scintillator layer 12 is, for example, 300 μm to 800 μm (300 μm or more and 800 μm or less).

The phosphor material used for the scintillator layer 12 is not limited to the above CsI, Tl, and the like. For example,
Basic composition formula (I): M ^I X a M ^II X ' ₂ b M ^III X'' ₃ : zA
An alkali metal halide phosphor represented by the following formula may be used.

In the above formula, M ^I represents at least one alkali metal selected from the group consisting of lithium (Li), Na, potassium (K), rubidium (Rb) and Cs.

M ^II consists of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), nickel (Ni), copper (Cu), zinc (Zn) and cadmium (Cd) It represents at least one alkaline earth metal or divalent metal selected from the group.

M ^III is scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), aluminum (Al), gallium (Ga) and indium This represents at least one rare earth element or trivalent metal selected from the group consisting of (In).

  X, X ′ and X ′ ′ each represent at least one halogen element selected from the group consisting of fluorine (F), chlorine (Cl), bromine (Br) and iodine (I).

  A consists of Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Na, Mg, Cu, silver (Ag), Tl and bismuth (Bi) It represents at least one rare earth element or metal selected from the group.

  a, b and z each represent a numerical value within the range of 0 ≦ a <0.5, 0 ≦ b <0.5, 0 <z <1.0.

It is preferable that M ^I in the above basic composition formula (I) contains at least Cs, and it is preferable that X contains at least I. In addition, A is particularly preferably Tl or Na. It is preferable that z be 1 × 10 ⁻⁴ ≦ z ≦ 0.1.

In addition to the above basic composition (I),
Basic composition formula (II): M ^II FX: zLn
The rare earth activated alkaline earth metal fluorohalide phosphor represented by In the above formula, M ^II represents at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca. Ln represents at least one rare earth element selected from the group consisting of Ce, Pr, Sm, Eu, Tb, Dy, Ho, Nd, Er, Tm and Yb. X represents at least one halogen element selected from the group consisting of Cl, Br and I. Also, z is 0 <z ≦ 0.2.

In addition, as M ^II in the above formula, it is preferable that Ba occupies half or more. As Ln, particularly preferably Eu or Ce.
Basic composition (III): Ln 2 O 2 S
The rare earth acid sulfide fluorescent substance represented by these may be used.
In the above formula, Ln represents at least two rare earth elements selected from the group consisting of La, Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Lu and Yb.
In addition, LnTaO ₄ : (Nb, Gd) system, Ln ₂ SiO ₅ : Ce system, LnOX: Tm system (Ln is a rare earth element), ZnWO ₄ , LuAlO ₃ : Ce, Gd ₃ Ga ₂₅ O ₁₂ Cr, Ce, HfO _{2 and the} like can be mentioned.

  As shown in FIG. 2, the partition wall 14 is provided to partition the scintillator layer 12 for each pixel corresponding to a plurality of pixels. That is, one region surrounded by the partitions 14 provided in a matrix in the vertical and horizontal directions is a region corresponding to one pixel PX provided on the sensor substrate 11. Alternatively, one region surrounded by the partition 14 may be a region corresponding to a plurality of pixels PX provided on the sensor substrate 11. Hereinafter, a region corresponding to each pixel PX of the scintillator layer 12 is referred to as a pixel corresponding region. As shown in FIG. 1, the above-mentioned photodiode 16 is disposed immediately below this pixel correspondence area.

  The material of the partition 14 contains an inorganic material as a main component. Alternatively, the material of the partition 14 may be only an inorganic material. Examples of the inorganic material include at least one of glass and ceramic. The material of the partition 14 contains 60% by weight or more and 100% by weight or less of glass. If the glass content is less than 60% by weight, the strength of the partition 14 is reduced, so it is desirable that the content is 60% by weight or more.

  When the amount of glass is 100% by weight or less, the material of the partition 14 may contain both glass and ceramic.

As glass, for example, silicate glass or borate glass is used. As components that can be contained in the glass _{also, SiO 2, Al 2 O 3} , B 2 O 3, ZnO, BaO, Bi 2 O 3, Li 2 O 3, Na 2 O, K 2 O, PdO, MgO, CaO , BaO, SrO, TiO ₂ , ZrO _{2 and the} like.

As the ceramic, for example, TiO ₂ · ZnO, ZrO · BaSO ₄ · BaCO ₃ · BaTiO ₃ · MgO · Pb _x O _y · PbTiO ₃ · ZnS are used.

  The sizes (width d1 and height d2) of the partition 14 shown in FIGS. 1 and 2 will be described later.

(Opposite substrate)
The counter substrate 13 is a glass plate having a thickness of, for example, 1 mm or less, and seals the scintillator layer 12 from the upper surface to prevent the intrusion of moisture into the scintillator layer 12. A resin coating may be applied to the side surface of the counter substrate 13 to enhance impact resistance (to prevent cracking caused by micro cracks), and reflection may be generated between the counter substrate 13 and the scintillator layer 12. Other layers such as membranes may be laminated.

  The material of the counter substrate 13 may be other than glass. As the material, Al, Cu, Fe, carbon plate, carbon fiber reinforced resin sheet, Si, Ge, GaAs, SiC, SiN, quartz, sapphire, PET, PEN, polycarbonate, polyimide film or the like is used.

  [Configuration of sensor board]

(Pixel part and peripheral circuit)
FIG. 3 schematically shows an example of the pixel section 10 in the sensor substrate 11 and a pixel drive circuit disposed in the peripheral area thereof. As described above, in the sensor substrate 11, the circuit unit 15 for driving the pixel unit 10 is disposed around the pixel unit 10. In the pixel unit 10, pixels (unit pixels) PX including the photodiodes 16 and transistors are arranged in a matrix. Each pixel PX is connected to a pixel drive line 27 (specifically, a row selection line) and a signal line 28.

  The circuit unit 15 includes, for example, a row scanning unit 23, a column scanning unit 25, and a system control unit 26. The row scanning unit 23 includes a shift register, an address decoder, and the like, and drives the pixel unit 10 in units of rows by supplying a drive signal to the pixel unit 10 through the pixel drive line 27. The column scanning unit 25 includes a shift register, an address decoder, and the like. The column scanning unit 25 sequentially receives signals corresponding to the amount of light received by the photodiode 16 provided in each pixel PX, which is output from the signal line, and outputs these signals to the outside.

  The circuit portion including the row scanning unit 23, the column scanning unit 25 and the signal line 28 may be a circuit integrated on the sensor substrate 11 or an external control IC connected to the sensor substrate 11. It may be arranged. In addition, those circuit portions may be formed on another substrate connected by a cable or the like.

  The system control unit 26 receives an externally supplied clock, data instructing an operation mode, and the like, and outputs data such as internal information of the radiation detector 1. The system control unit 26 also has a timing generator that generates various timing signals, and drives the row scanning unit 23 and the column scanning unit 25 based on the various timing signals generated by the timing generator. Control.

  FIG. 4 shows an example of a circuit (pixel circuit 20) of the pixel PX driven by the pixel drive circuit shown in FIG.

  The pixel circuit 20 is a circuit employing, for example, a passive matrix driving method, and includes a photodiode 16, a capacitor 138, and a transistor Tr.

  The photodiode 16 is a device that generates a signal charge of a charge amount according to the light amount (light reception amount) of incident light. The photodiode 16 and the capacitive component 138 are connected in parallel to the supply line 174 of the reference potential Vxref. That is, the photodiode 16 is connected between the supply line 174 and the storage node N which is one end of the capacitor 138.

  A row operation signal (read signal) Vread is supplied to the row selection line 173. The gate of the transistor Tr is connected to the row selection line 173, and the source and the drain are connected to the storage node N and the signal line 28, respectively. The voltage corresponding to the row operation signal Vread is applied to the gate of the transistor Tr, whereby the signal charge of the charge amount corresponding to the light reception amount of the photodiode 16 accumulated in the capacitor 138 is transmitted through the accumulation node N. It is output to the signal line 28.

  [Method of manufacturing radiation detector]

  FIG. 5 is a flowchart showing a method of manufacturing a radiation detector according to the present embodiment.

  First, a reflection film (reflection layer) (not shown) is formed on the counter substrate 13 (step 101). As a reflective film, for example, a glass paste (a material obtained by mixing glass particles, ceramic particles, an organic binder, and an organic solvent) is applied on the opposing substrate 13 by a blade coater, whereby a reflective film is formed. The thickness of the reflective film is, for example, 30 μm. In addition, the said organic solvent does not need to be used depending on the case, and the glass paste to which the other additive component was added may be used.

  A drying process of the opposing substrate 13 on which the reflective film is formed is performed (step 102). In this drying process, for example, a heat treatment is performed at a temperature of 80 ° C. for about 10 minutes.

  After the drying process, a firing process of the object is performed (step 103). By this baking treatment, the organic binder contained in the glass paste is removed. This baking process is, for example, at a temperature of 550 ° C. for about 10 minutes.

  A photosensitive paste is applied on the opposing substrate 13 (on the reflective film) as a material for forming the partition 14 (step 104). The photosensitive paste is a material in which glass particles and a photosensitive organic binder are mixed.

  In some cases, a photosensitive paste to which an organic solvent or other additive component is added may be used. The additive component is, for example, a photopolymerization initiator, an ultraviolet light absorber, a sensitizer, a sensitizer, a polymerization inhibitor, a plasticizer, a thickener, an antioxidant, or a dispersant precipitation inhibitor, etc. is there.

  After the photosensitive paste is applied, the object is dried (step 105). In this drying process, for example, a heat treatment at a temperature of 80 ° C. for about 60 minutes is performed.

  The photosensitive paste is patterned in the shape of the partition 14 as shown in FIGS. 1 and 2 by the exposure processing of the photosensitive paste material using a photomask and the development processing thereof (steps 106 and 107). The photosensitive paste material contains an inorganic material of at least one of the above-described glass and ceramic for forming the partition walls.

  After the development process of step 106, the object is dried (step 108). In this drying process, for example, heat treatment is performed at a temperature of 120 ° C. for about 60 minutes.

  After the drying process, a firing process of the object is performed (step 109). By the baking process, the organic binder contained in the photosensitive paste is removed. This baking process is, for example, about 30 minutes at a temperature of 550.degree.

  After the firing process, partition walls 14 having the following width d1 are obtained. The width d1 of the partition wall 14 is 10 μm to 40 μm, and more preferably 10 μm to 30 μm. If the width d1 of the partition 14 is smaller than 10 μm, the formation thereof becomes difficult, and if larger than 40 μm, the aperture ratio (the aperture ratio for each pixel PX) and the resolution can not be made as desired design values. Here, the width of the partition 14 means the width at half the height d 2 of the partition 14.

  In addition, the aspect ratio of the partition 14 comprised as mentioned above is 10-20, 10-27, or 30-80.

  In the case of screen printing, it is difficult to form a partition having a width smaller than 30 μm due to excessive leakage of paste material from the pattern opening of the mask. Also, even if partition walls with a width greater than 30 μm can be formed by screen printing, in the case of screen printing, in order to realize partition walls with a height of 300 μm to 800 μm as described above, It needs to be repeated again and again. For example, in the case of screen printing, the coating film thickness in one coating process is 10 μm. Therefore, to achieve 300 μm, 30 coating processes (overcoating) are required, which requires a great deal of labor and time.

  Moreover, in the case of screen printing, there is a problem that the positional accuracy of the formation of the partition wall is deteriorated as the panel size is increased. In particular, since multiple over-coatings are performed, if the positional accuracy in each over-coating is poor, the formation position is shifted for each over-coating, so the width of the formed partition is larger than the targeted width of the partition turn into. Further, in screen printing, the width of the partition becomes large at a position where the vertical and horizontal lines of the partition cross (for example, a region indicated by reference numeral B1 shown in FIG. 1), which causes a problem that the size accuracy is poor.

  On the other hand, in the manufacturing method according to the present embodiment, as described above, the photolithography technique using a photosensitive paste material containing an inorganic material such as glass is used to form the partition 14 with a small width as described above. And, partition walls having a high aspect ratio can be formed. According to the present embodiment, the partition 14 having the above-described size can be formed by one or two exposure and development processes. Further, according to the photolithography technology using the photosensitive paste, the positional accuracy and the size accuracy of the partition wall 14 are significantly improved.

After the firing process, the phosphor material, that is, the material constituting the scintillator layer 12 is filled in the area surrounded by the partition walls 14 (step 110). As a fluorescent substance material, for example, a powder paste produced by mixing Gd ₂ O ₂ S: Tb powder, an organic binder and an organic solvent is used. Organic solvents may not be used in some cases. The powder paste is applied by a blade coater. The coating film thickness of this phosphor material is about the same as or higher than the height of the partition wall 14.

  A drying process (for example, about 60 minutes at 80 ° C.) and a baking process (for example, about 30 minutes at 500 ° C.) are performed (steps 111 and 112). In addition, the surface (the surface on which the partition 14 and the scintillator material are exposed) opposite to the side on which the opposing substrate 13 of the object is provided is polished. This removes the extra mainly phosphor material left on the surface. Moreover, the height of the partition 14 and the scintillator material becomes substantially the same and constant in the surface by this polishing. The polishing process may not be necessary.

  An adhesive is applied to the polished surface (step 113). As the adhesive, a material in which an organic solvent is mixed with an organic binder is used. The application thickness is, for example, 25 μm, and an adhesive is applied by a blade coater (step 114). Thereafter, a drying process (for example, about 5 minutes at 80 ° C.) is performed (step 115). The adhesive application process may not be necessary.

  The sensor substrate 11 described above is prepared, and the sensor substrate 11 is bonded to the counter substrate 13 provided with the scintillator layer 12 and the partition 14 (step 116). In this case, the two substrates are bonded so that the regions of the plurality of pixels PX provided on the sensor substrate 11 correspond to the pixel corresponding regions of the scintillator layer 12.

  [Relationship between partition size and brightness]

(About the width)
FIG. 6 is a graph showing the relationship between the width (d1) of the partition wall and the brightness (brightness ratio) obtained by the radiation detector having the partition wall of the width. FIG. 7 is a table showing the relationship.

  In this experiment, the luminance when a partition having a width of 35 μm and a height of 400 μm is formed by screen printing is 100%, and this and the luminance when a partition 14 is formed of the photosensitive paste of the present technology and Compare. In this case, in each case, the height of the partition was set to 400 μm.

  In FIG. 7, in the case of the partition wall having a width of 40 μm, that is, in the case of the partition wall of 10 μm to 35 μm, a high value could be obtained as compared to the screen printing.

  The reason for the higher luminance of the latter with screen printing width 35 μm and photosensitive paste width 35 μm is that, as mentioned above, the partition width becomes large at the position where the vertical and horizontal lines of the partition cross. It is. That is, this is because the aperture ratio is reduced.

(About the height)
FIG. 8 is a graph showing the relationship between the height (d2) of the partition wall and the brightness (brightness ratio) obtained by the radiation detector having the partition wall with the height. FIG. 9 is a table showing the relationship.

  In this experiment, for example, the luminance when the height of the partition is 150 μm is 100%, and this is compared with the luminance when the partition 14 made of the photosensitive paste of the present technology is formed. In this case, in each case, the width of the partition was 30 μm.

  As the height increases to a predetermined height (400 μm to 600 μm in this experiment), the amount of scintillator material in the pixel correspondence region increases, so the radiation absorption amount increases accordingly, and the saturation point exists However, the amount of light emission, that is, the luminance increases. However, it has been found that the luminance decreases when the height exceeds the predetermined height. We believe that the optimal height range is 300 μm to 800 μm.

  The volume of the scintillator layer 12 can be increased by providing the partition 14 having a high height and a narrow width as in the partition 14 according to the present embodiment. That is, radiation, in this case X-rays, can be efficiently converted to visible light, and high sensitivity can be realized.

  In particular, by using a photolithographic technique using a photosensitive paste, it is possible to precisely form the partition walls 14 with a high aspect ratio.

  [Other embodiments of scintillator layer etc.]

  Next, a radiation detector according to another embodiment will be described, and mainly, some embodiments of a layer included in the scintillator layer or formed on the scintillator layer will be described. In the following description, the description of the same matters is simplified or omitted for the radiation detector according to the embodiment shown in FIG. 1 etc. and the method of manufacturing the radiation detector shown in FIG. I will explain to the center.

(Example 1)
FIG. 10 shows a radiation detector according to example 1. The radiation detector 51 includes a sensor substrate 11, an opposite substrate 13, a partition 14 and a scintillator layer 52. The scintillator layer 52 includes a phosphor layer 521 formed of a phosphor material, and a mixed layer 522 including both a phosphor material and a resin material. The mixed layer 522 is provided between the phosphor layer 521 and the sensor substrate 11.

In this case, the height of the partition 14 is preferably 300 μm to 800 μm, as described above.
It is 400 micrometers-600 micrometers. The size of the partition wall 14 can be similarly applied to the embodiments according to Examples 2 to 4 described later. The thickness of the mixed layer is desirably 10 μm to 200 μm.

  FIG. 11 is a diagram for explaining a method of manufacturing the radiation detector shown in FIG. FIG. 12 is a flowchart showing the manufacturing method.

  Steps 101 to 112 or 113 in FIG. 5 are performed. As a result, a scintillator layer 521 'formed of a phosphor material is formed. Thereafter, a solution 522 'in which the resin material is dissolved in an organic solvent and made liquid is applied onto the scintillator layer 521' (step 210). Instead of the solution, the resin material itself may be applied.

  In step 210, the flow rate of the solution 522 'discharged from the nozzle 40, the moving speed of the nozzle 40, and the like are adjusted to form the mixed layer 522 having the predetermined thickness as described above.

  As the resin material, for example, nitrifying cotton, cellulose acetate, ethyl cellulose, polyvinyl butyral, cotton-like polyester, polyvinyl acetate, vinyl chloride, vinylidene chloride, vinyl chloride copolymer, vinylidene chloride-vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, Polyalkyl (meth) acrylate, polycarbonate, polyurethane, cellulose acetate butyrate, epoxy, silicone, polyolefin, polyester, polyamide rubber (acacia gum), urethane-modified polyester, gelatin, dextran, nitrocellulose, polyalkyl methacrylate, or polyvinyl alcohol Alcohol etc. are mentioned.

  As the organic solvent, for example, methanol, ethanol, propanol, methyl ethyl ether, acetone, MEK, MIBK, butyl acetate, ethyl acetate, ethyl ether, xylene, toluene and the like are used. Also, if necessary, dispersants such as phthalic acid and stearic acid, and plasticizers such as triphenyl phosphate and diethyl phthalate may be added to the organic solvent.

  Thereafter, the mixed layer is formed by subjecting the target substrate (the opposite substrate 13 on which the partition 14 and the scintillator layer 52 are formed) to be treated as described above to drying or curing, or the like. (Step 211). Then, the sensor substrate 11 and the target substrate are bonded so that the scintillator layer 52 is disposed on the sensor substrate 11.

  Here, in the process of manufacturing the radiation detector, when the phosphor material is in the form of powder, after the phosphor material is filled in the partition wall 14, for example, the powder or granular fluorescent light during transportation or processing of the substrate. There is a risk of body material falling off the substrate (dropping). In the present embodiment, a solution containing a resin material is applied onto the scintillator layer 521 ′, so that after the resin is dried or cured, the mixed layer 522 containing the resin material functions as a cap layer in the scintillator layer. . That is, by providing the cap layer, it is possible to prevent the falling off of the phosphor material that may occur in the manufacturing process of the radiation detector 51.

(Example 2)
FIG. 13 is a diagram for explaining a method of manufacturing a radiation detector according to Example 2.
In the radiation detector 61 according to the second embodiment, the region 62 in the partition 14 formed on the counter substrate 13 is filled with the material 62 ′ including both the phosphor material and the resin material, and the firing after the filling (for example, By not performing “baking” corresponding to step 112 in FIG. 5, the resin material is not removed and remains distributed in the scintillator layer 62 as a whole. This resin material may be the resin material mentioned in Example 1 above.

  Drying or curing of the resin material can prevent the phosphor material from falling off.

  After the scintillator layer 62 including the resin material and the phosphor material is manufactured as described above, a sensor substrate (not shown) is bonded to the counter substrate 13.

(Example 3)
FIG. 14 is a diagram for explaining the method of manufacturing the radiation detector according to the third example.
In the radiation detector 71 according to the third example, a region 72 in the partition 14 formed on the counter substrate 13 is filled with a material 72 ′ including both a phosphor material and a glass material (for example, glass particles). This is then fired. The state and content of the glass can be appropriately adjusted depending on the conditions such as the temperature and time of firing.

  After the scintillator layer 72 including the glass material and the phosphor material is manufactured as described above, a sensor substrate (not shown) is bonded to the counter substrate 13.

  Also in the present embodiment, it is possible to prevent the falling off of the phosphor material in the process of manufacturing the radiation detector 71.

(Example 4)
FIG. 15 is a drawing for explaining the manufacturing method of the radiation detector relating to Example 4.
In the radiation detector 81 according to the fourth example, the region in the partition 14 formed on the counter substrate 13 is filled with the phosphor material. Then, the sheet 82 containing the resin material is transferred onto the partition walls 14 and the scintillator layer 12. The sheet 82 functions as a cap layer provided between the scintillator layer 12 and the partition 14 and the sensor substrate (not shown).

  The thickness of the sheet is, for example, 10 μm to 100 μm.

  As a sheet | seat, it divides roughly, for example, and it is divided into a hot-melt-type adhesive material sheet and an adhesive agent sheet (adhesive system sheet). Examples of the hot melt adhesive sheet include polyolefins, polyesters, and polyamides. As an adhesive sheet, acrylic, polyurethane, silicone, rubber (gum arabic), polyester, urethane modified polyester, gelatin, dextran, polyvinyl butyral, polyvinyl acetate, nitrocellulose, ethyl cellulose, vinylidene chloride, vinyl chloride copolymer, polyalkyl meta Acrylate, vinyl chloride, vinyl acetate copolymer, cellulose acetate butyrate, polyvinyl alcohol, linear polyester and the like can be mentioned.

  Also in the present embodiment, it is possible to prevent the falling off of the phosphor material in the process of manufacturing the radiation detector 81. If a sheet is prepared in advance, the cap layer can be formed simply by sticking the sheet 82 on the target substrate, so the manufacture of the cap layer becomes easy.

(Example 5)
FIG. 16 is a diagram for explaining the method of manufacturing a radiation detector according to the fifth example. FIG. 17 is a flowchart showing the manufacturing method.

  In this example, after steps 101 to 111, 100 to 112, or 100 to 113 in FIG. 5 are performed, paste material 92 in which the phosphor material and the resin material are mixed is applied onto partition 14 and scintillator layer 12. Ru. Thereby, a cap layer is formed. Alternatively, a sheet (not shown) containing a phosphor material and a resin material may be transferred onto the partition walls 14 and the scintillator layer 12. Thereafter, a drying or curing process is performed (step 311).

  In this case, the height of the partition 14 is 200 μm to 600 μm. In these cases, the thickness of the cap layer is desirably 50 μm to 300 μm. More preferably, it is 150 μm to 300 μm.

  As the resin material, for example, nitrifying cotton, cellulose acetate, ethyl cellulose, polyvinyl butyral, cotton-like polyester, polyvinyl acetate, vinyl chloride, vinylidene chloride, vinyl chloride copolymer, vinylidene chloride-vinyl chloride copolymer, vinyl chloride-vinyl acetate copolymer, Polyalkyl (meth) acrylate, polycarbonate, polyurethane, cellulose acetate butyrate, epoxy, silicone, polyolefin, polyester, polyamide rubber (gum arabic), urethane modified polyester, gelatin, dextran, nitrocellulose, polyalkyl methacrylate or polyvinyl alcohol Alcohol etc. are mentioned.

  As the organic solvent, for example, methanol, ethanol, propanol, methyl ethyl ether, acetone, MEK, MIBK, butyl acetate, ethyl acetate, ethyl ether, xylene, toluene and the like are used. Also, if necessary, dispersants such as phthalic acid and stearic acid, and plasticizers such as triphenyl phosphate and diethyl phthalate may be added to the organic solvent.

  As in the embodiment according to Example 4, when the cap layer including only the resin material is provided on the scintillator layer, a decrease in luminance may occur. However, since the cap layer according to the present embodiment according to the fifth example includes the phosphor material, the drop of the phosphor material can be prevented without lowering the luminance.

  As in the first to fourth examples, when the scintillator layer substantially separates each pixel by the partition wall 14, the resolution is improved because light does not pass between the pixels. However, in this case, noise (white noise) may increase because the properties of photons of radiation (such as fluctuations in the distribution of the probability of existence of particles that are quantum specific properties) can be reflected in the image. On the other hand, in the present embodiment according to Example 5, since the cap layer is provided between the partition wall 14 and the scintillator layer 12 and the sensor substrate, the end 14 a of the partition wall 14 on the sensor substrate side is a sensor It is separated from the substrate 11 via a cap layer (paste material 92). This alleviates the individual independence of the sensors in the sensor substrate and reduces the noise.

  As described above, since the resolution and the noise are in a trade-off relationship in a certain region, the examples 1 to 5 may be appropriately selected according to the design.

  Other Embodiments

  The present technology is not limited to the embodiments described above, and various other embodiments can be realized.

  In the manufacturing method according to the above embodiment, the partition wall is formed on the counter substrate side, but the partition wall may be formed on the sensor substrate side, and then the sensor substrate on which the partition wall is formed may be bonded to the counter substrate . When the partition wall is formed on the sensor substrate side, the counter substrate may not be present. In that case, a reflective layer is formed on the side opposite to the sensor substrate.

  Also, in the other embodiments of the scintillator layer and the like described in the above Examples 1 to 5, the barrier ribs and the scintillator layer may be formed on the sensor substrate side. In this case, the counter substrate and the sensor substrate may be bonded. In this case, the sensor substrate and the counter substrate are attached to each other such that the scintillator layer on which the material including at least the resin material is applied or transferred as described above is disposed on the counter substrate. Alternatively, the opposite substrate may not be present.

  In the manufacturing method according to the above-described embodiment, the scintillator layer is formed by filling and baking the phosphor material in step 109. However, the phosphor material may be filled in the area surrounded by the barrier ribs by vapor deposition through the vapor deposition mask having the shape pattern of the barrier ribs.

  Among the steps in the manufacturing method according to the above-described embodiment, for example, the temperature and time of drying, baking and the like can be changed as appropriate.

  In the said embodiment, although the glass and the ceramic were mentioned as an example of the inorganic material of the photosensitive paste, another material may be sufficient.

In each of the above embodiments, the height of the partition wall 14 is not limited to 300 to 800 μm and 400 to 600 μm as described above. It may be 300-600 μm, 300-500 μm, 300-450 μm, 300-400 μm, 400-700 μm, 450-650 μm, or 450-700 μm, 500-700 μm, 500-600 μm, or the like.
In each of these cases, as described above, the thickness of the partition 14 can be in the range of 10 μm to 40 μm, 10 μm to 35 μm, or 10 μm to 30 μm, 20 to 40 μm, 20 to 35 μm, 20 to 30 μm, etc. .

  The glass transition temperature of the glass used for the opposing substrate according to each of the above embodiments may be, for example, 600 ° C. or higher. This is in consideration of the heat resistance of the sensor and the substrate in the manufacturing process.

Although glass was assumed in the above embodiment as a material of the sensor substrate 11 according to each of the above embodiments, a semiconductor substrate may be used.
In that case, the glass transition temperature may be 600 ° C. or more as described above. The specific gravity of the substrate may be 2.4 g / cm ³ or less, and the thickness thereof may be 0.5 mm to 1.0 mm, but is not limited to these values.
Further, the thermal expansion coefficient on the sensor substrate 11 side may be in the range of ± 20% with respect to that of the glass substrate. This is to suppress positional deviation between the sensor and the scintillator due to the difference in thermal expansion coefficient between the two being too large.

As a fluorescent substance material concerning each above-mentioned embodiment, when it is powder particles, for example, an average diameter of the powder particles may be 5 micrometers-15 micrometers. If the diameter is smaller than 5 μm, desired brightness can not be obtained, and if the diameter is larger than 15 μm, filling into the partition 14 becomes difficult.
In addition, the melting point of the phosphor material may be 600 ° C. or less in the manufacturing process as described above.

  It is also possible to combine at least two features of the features of each embodiment described above.

The present technology can also be configured as follows.
(1) a sensor substrate having a plurality of pixels capable of receiving light;
A scintillator layer provided on the sensor substrate;
A radiation detector comprising: a partition wall having a height of 300 μm to 800 μm and a width of 10 μm to 40 μm and provided to partition the scintillator layer for each pixel.
(2) The radiation detector according to (1), wherein
The main component of the material of the said partition is an inorganic material. Radiation detector.
(3) The radiation detector according to (2), wherein
The said inorganic material contained in the said partition contains at least one among glass and a ceramic. Radiation detector.
(4) The radiation detector according to (2) or (3),
The material of the said partition contains 60 weight% or more and 100 weight% or less glass Radiation detector.
(5) The radiation detector according to any one of (1) to (4), wherein
The scintillator layer includes a phosphor material and a resin material.
(6) The radiation detector according to (5), wherein
The scintillator layer is
A phosphor layer formed of the phosphor material;
Wherein disposed between the phosphor layer and said sensor substrate, a radiation detector including a mixed layer containing both the fluorescent material and the resin material.
(7) The radiation detector according to any one of (1) to (4), wherein
The scintillator layer includes a phosphor material and a glass material.
(8) The radiation detector according to any one of (1) to (4), wherein
The scintillator layer comprises a phosphor material,
The radiation detector further includes a cap layer provided between the scintillator layer, the partition wall, and the sensor substrate.
(9) The radiation detector according to (8), wherein
The cap layer contains at least a resin material.
(10) The radiation detector according to (9), wherein
The said cap layer contains the material which mixed the said fluorescent substance material and the said resin material. Radiation detector.
(11) A partition wall is formed on a substrate by exposure processing of a photosensitive paste material using a photomask and its development processing,
By baking the substrate on which the partition is formed, the partition having a height of 300 μm to 800 μm and a width of 10 μm to 40 μm is formed.
A method of manufacturing a radiation detector, wherein after firing, a scintillator material is filled in an area surrounded by the partition walls on the substrate.
(12) It is a manufacturing method of the radiation detector given in (11),
The method for manufacturing a radiation detector, wherein the photosensitive paste material contains an inorganic material and an organic binder.
(13) A method of manufacturing a radiation detector according to (11) or (12), wherein
The substrate is an opposing substrate that faces a sensor substrate having the plurality of light-receiving pixels.
The barrier ribs are formed to correspond to a plurality of pixels,
A method of manufacturing a radiation detector, further comprising: bonding the sensor substrate and the counter substrate such that a scintillator layer composed of the scintillator material is disposed on the sensor substrate.
(14) A method of manufacturing a radiation detector according to any one of (11) to (13),
A method of manufacturing a radiation detector, further comprising the step of applying or transferring a material containing at least a resin material on a scintillator layer formed by filling the scintillator material.
(15) A method of manufacturing a radiation detector according to (14), wherein
The said application | coating process apply | coats the solution containing the said resin material on the said scintillator layer. The manufacturing method of a radiation detector.
(16) A method of manufacturing a radiation detector according to (14), wherein
The method of manufacturing a radiation detector, wherein the transfer step transfers a sheet material containing the resin material onto the scintillator layer.
(17) A method of manufacturing a radiation detector according to (14), wherein
In the application step, a paste material containing a phosphor material and the resin material is applied on the scintillator layer. A method of manufacturing a radiation detector.
(18) A method of manufacturing a radiation detector according to (11) or (12),
The substrate is a sensor substrate having a plurality of light receiving pixels.
The partition wall is formed to correspond to the plurality of pixels.
(19) A method of manufacturing a radiation detector according to (18), wherein
Applying or transferring a material containing at least a resin material on the scintillator layer formed by filling the scintillator material on the sensor substrate;
Bonding the sensor substrate and the counter substrate such that the scintillator layer to which the material is applied or transferred is disposed on the counter substrate.

DESCRIPTION OF SYMBOLS 1, 51, 61, 71, 81, 91 ... Radiation detector 11 ... Sensor substrate 12, 52, 62, 72 ... Scintillator layer 13 ... Counter substrate 14 ... Partition 14 16 ... Photodiode 82 ... Sheet 92 ... Paste material

Claims (5)

A sensor substrate having a plurality of pixels capable of receiving light;
A scintillator layer provided on the sensor substrate such that it has a flat surface and the flat surface faces the plurality of pixels ;
A partition wall having a height of 300 μm to 800 μm and a width of 10 μm to 40 μm and provided to partition the scintillator layer for each pixel;
An opposing substrate provided opposite to the sensor substrate through the scintillator layer and the partition wall;
A cap layer provided between the flat surface of the scintillator layer and the sensor substrate and including a phosphor material and a resin material and having a thickness of 150 μm or more and 300 μm or less;
A radiation detector comprising: a reflective film provided between the counter substrate and the scintillator layer. The radiation detector according to claim 1, wherein
The material of the said partition contains 60 weight% or more and 100 weight% or less glass Radiation detector. A method of manufacturing a radiation detector, comprising: a sensor substrate having a plurality of pixels capable of receiving light; and an opposing substrate facing the sensor substrate,
Forming a reflective film on the opposing substrate;
Applying a photosensitive paste material on the reflective film on the counter substrate;
A partition wall is formed on a substrate by exposure processing of the photosensitive paste material using a photomask and development processing thereof.
By baking the substrate on which the partition is formed, the partition having a height of 300 μm to 800 μm and a width of 10 μm to 40 μm is formed.
After the firing, a scintillator material is filled in a region surrounded by the partition walls on the substrate,
The opposite side to the opposite substrate of the scintillator layer formed by filling the scintillator material is polished to form a polished surface, and a sheet material containing a phosphor material and a resin material is transferred onto the polished surface , or By applying a paste material containing a phosphor material and a resin material, a cap layer having a thickness of 150 μm to 300 μm is formed.
After the transfer of the sheet material or the application of the paste material, the sensor substrate and the opposite substrate are pasted so that the scintillator layer and the cap layer thereon are disposed between the sensor substrate and the opposite substrate. Method of manufacturing radiation detectors. A method of manufacturing a radiation detector according to claim 3, wherein
The material of the said partition contains 60 weight% or more and 100 weight% or less glass. The manufacturing method of the radiation detector. A method of manufacturing a radiation detector according to claim 3 or 4, wherein
The method for manufacturing a radiation detector, wherein the scintillator material includes powdery phosphor material.