JP2005043330A - X-ray image detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a miniaturized X-ray image detector superior in impact durability. <P>SOLUTION: The X-ray image detector 10, in which an X-ray imaging part 24 for converting an X-ray image into an electrical signal is housed in a container 14, includes a substrate 22 for supporting the X-ray imaging part. The substrate is provided with a base material layer 40, having an X-ray shield function, circuit layers 44 and 48 for transmitting the signal from the X-ray imaging part, and electrically insulating layers 42 and 46 brought into contact with and sandwiched between the X-ray base material layer and the circuit layers. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an X-ray image detector, for example, an X-ray image detector for detecting and displaying an X-ray image of an intraoral site as an electrical signal. The present invention also relates to a method of manufacturing a substrate that supports an X-ray imaging unit in an X-ray image detector.

Conventionally, an X-ray image sensor used for converting an X-ray image of an intraoral site into an electrical signal and displaying the image has been proposed in Japanese Patent Laid-Open Nos. 5-130991 and 7-280944. . Japanese Patent Application Laid-Open No. 10-282243 discloses the use of ceramic for the substrate.
Japanese Patent Laid-Open No. 5-130991 JP-A-7-280944 JP-A-10-282243

  These X-ray image sensors generally have a phosphor that emits light in response to X-rays transmitted through a container, and a light carrier that carries light generated by the phosphor on a substrate housed in a sealed container. A member and an image pickup device that receives the light transported by the light transporting member and generates an electrical signal corresponding to the X-ray image are stacked. The substrate also supports an electrical circuit layer and a connector for connecting one end of the cable drawn into the container to the electrical circuit layer in order to transmit a signal obtained by the imaging device to an external device. .

  However, in such a conventional X-ray image sensor, the main part of the substrate is made of ceramics that transmit X-rays. Therefore, in order to prevent scattered X-rays from entering the image sensor from the back surface of the substrate (the surface opposite to the surface supporting the image sensor, etc.), it is necessary to separately arrange an X-ray shielding layer on the substrate back surface side. There is. In addition, ceramics have low impact durability and may be damaged by accidents such as dropping. And when the ceramic which is a board | substrate is damaged, the circuit currently formed on the ceramic board | substrate short-circuits, and there also exists a problem that it heat-generates there. Furthermore, since the X-ray shielding layer provided separately and the necessity of ensuring a certain thickness of the ceramic substrate to prevent breakage are required, the thickness of the substrate increases, and the detector itself increases accordingly. .

In particular, when it is used as an X-ray image detector for detecting X-rays in the oral cavity, it is required to be as thin and small as possible because the space in the oral cavity is limited. If the substrate is made thinner in order to reduce the size, the impact durability is lowered as described above, so that there is a conflicting demand that a sufficient strength must be ensured.
Therefore, an object of the present invention is to provide a thin and small X-ray image detector excellent in impact durability.

  In response to such a problem, the present invention provides an X-ray image detector in which an X-ray imaging unit that converts an X-ray image into an electrical signal is contained in a container. It is characterized by comprising a base material layer having a shielding function, a circuit layer for transmitting a signal from the X-ray imaging unit, and an electrical insulating layer held in contact with the base material layer and the circuit layer. The base material layer may be formed of an X-ray shielding layer and a metal layer, or may be composed of an X-ray shielding layer, a metal layer, and an electric insulating layer sandwiched between the X-ray shielding layer and the metal layer. Also good. The base material layer can be formed of any of an alloy containing nickel, silver, tungsten, an alloy containing tungsten, or carbon steel. Alternatively, when the base material layer includes an X-ray shielding layer and a metal layer, the X-ray shielding layer is made of an alloy containing nickel, silver, tungsten, an alloy containing tungsten, gold, lead, or carbon steel. Can be formed. The metal layer is composed of nickel alloy, silver, tungsten, tungsten alloy, aluminum, aluminum alloy, magnesium alloy, iron, carbon steel, stainless steel, chrome steel, copper and zinc It can be formed from any of the alloys. A conductive path for connecting a metal base layer having an X-ray shielding function to the ground may be provided. In an X-ray image detector in which an X-ray imaging unit that converts an X-ray image into an electrical signal is contained in a container, the substrate that supports the X-ray imaging unit may be made of a metal having an X-ray shielding function.

  According to another aspect of the present invention, there is provided a method for manufacturing a substrate in a method for manufacturing a substrate that supports an X-ray imaging unit in an X-ray image detector in which an X-ray imaging unit that converts an X-ray image into an electrical signal is contained in a container. A circuit is formed by sandwiching and electrically fixing an electrically insulating material between a metal layer having X-ray shielding properties and a conductive metal layer, and partially removing the conductive metal layer. In another method of manufacturing a substrate, an X-ray shielding metal layer and a metal layer are adjacent to each other, and an electric insulation is provided between the X-ray shielding metal layer or the metal layer and the conductive metal layer. The conductive material is sandwiched and fixed to each other, and the conductive metal layer is partially removed to form a circuit. Furthermore, in another embodiment of the method for manufacturing a substrate, an electrically insulating material is sandwiched between a metal layer having an X-ray shielding property and the metal layer, and the metal layer having the X-ray shielding property or the metal layer An electrically insulating material is sandwiched between the conductive metal layers, all are fixed to each other, and the conductive metal layer is partially removed to form a circuit.

  According to the X-ray image detector configured as described above and the method for manufacturing the substrate, the main part of the substrate is configured with a metal base layer that is superior in impact durability to ceramics. The substrate and the detector can be reduced in thickness and size, and the impact durability of the detector is improved.

  1A to 1C show an X-ray image detector 10 according to Embodiment 1 of the present invention. The X-ray image detector 10 is irradiated from the opposite side of the imaging region by applying the detection surface 12 (the lower surface of the detector shown in FIGS. 1B and 1C) to the imaging region (for example, teeth and gingiva) in the oral cavity. By detecting X-rays, an X-ray image of the imaging region is obtained. For such a purpose, the container 14 constituting the main part of the X-ray detector 10 has a size that can be inserted into the oral cavity (for example, a width of 38.5 mm, a depth of 25 mm, and a height of 7.5 mm. However, the height is high. 2B, except for the raised portion for accommodating the signal cable shown on the upper right side of FIG. 1B.) And having two container parts 16, 18 formed of a material that is transparent to X-rays. It is configured in combination. The assembly 20, which is housed inside the container 14 and becomes an X-ray imaging unit, is roughly supported by the substrate 22, the imaging unit 24 supported on one surface of the substrate 22, and the other surface of the substrate 22. The electrical connection portion 26 is formed.

The imaging unit 24 includes three members stacked in order from the detection surface 12 toward the substrate 22, that is, a phosphor (scintillator) 28, a light propagation element 30, and a charge coupled device (CCD) 32. Among these, the phosphor 28 emits visible light upon receiving X-rays transmitted through the detection surface 12, and is made of, for example, a rare earth element compound. The light propagating element 30 optically connects the phosphor 28 and the charge coupled device 32, and a large number of optical fibers are arranged in the opposing direction of the phosphor 28 and the charge coupled device 32 (vertical direction in the drawing). It is arranged and configured. The charge coupled device 32 receives light carried by each light propagation device 30 and converts it into an electrical signal, and creates an electrical image signal corresponding to the two-dimensional distribution of fluorescence emitted from the phosphor 28. .
In this embodiment, a CCD is used for the image pickup unit 24, but a MOS sensor or other image pickup element may be used as appropriate.

  The electrical connection portion 26 includes a connector 38 that electrically connects one end of the signal cable 34 introduced from the outside to the inside of the container 14 and the circuit component 36 installed on the substrate 22. In the present embodiment, in order to reduce the size of the X-ray image detector 10, the signal cable 34, the connector 38, and the like are arranged on the opposite side of the imaging unit 24 across the substrate 22. The imaging unit 24 and the electrical connection unit 26 may be arranged on one side.

  The substrate 22 has an overall thickness of about 0.5 mm. For example, as shown in FIG. 1D in which a part of FIGS. 1A to 1C is enlarged, the substrate 22 is centered on a metal base layer 40 that is a metal base layer. As described above, the first electric insulating layer 42 and the first circuit layer 44 are supported on one surface (upper surface in the figure) of the metal base layer 40, and the second surface (lower surface in the diagram) is supported on the second surface. The circuit component 36 shown in FIGS. 1A and 1B is electrically connected to the first circuit layer 44 at the upper side of the figure, and supports the electrical insulating layer 46 and the second circuit layer 48. The charge coupled device 32 is electrically connected to a certain second circuit layer 48.

  1D is completed, after the substrate 22 is completed, the imaging unit 24 is fixed at a position indicated by an arrow 24a (a position adjacent to the lowermost circuit layer 48). Then, the X-ray enters the imaging unit from the direction indicated by the arrow 24a. The X-ray traveling direction is the same for FIGS. 3A to H, FIGS. 4, 5, and 6A in which the imaging unit and the arrow are omitted from the drawing.

  The metal substrate layer 40 is preferably made of an alloy containing nickel, for example, an alloy containing 42% nickel and iron as the remaining component (trade name 42 alloy). In addition, an alloy containing tungsten such as silver, tungsten, and copper tungsten, and a metal having X-ray shielding properties such as carbon steel can be used. The first and second electrically insulating layers 42 and 46 are made of, for example, an epoxy resin. The first and second circuit layers 44 and 48 are formed of a thin layer of conductive metal (for example, copper), and a necessary circuit is formed by partial removal by a process such as etching.

  A method for manufacturing the substrate 22 will be described with reference to FIGS. 2 and 3A to 3H. First, as shown in FIG. 2, a lead frame 50 made of a thin metal plate to be a metal base layer 40 which is a metal layer having X-ray shielding properties is prepared. As shown in the drawing, in the lead frame 50, for example, a groove (slot) 52 that forms the contour of the metal base layer 40, and first and second circuit layers 44 and 48 that are conductive metal layers are electrically connected. A hole 54 for forming a circuit for connection is formed in advance. Next, as shown in FIG. 3A, insulating material layers (prepregs) 56, 58 to be first and second electric insulating layers 42, 46 made of an electric insulating material, and first and second circuit layers 44, The conductive metal layers 60 and 62 to be 48 are arranged on the upper surface and the back surface of the metal base layer 40 and pressed by applying pressure from above and below, and the insulating material layers 56 and 58 and the conductive metal layers 60 and 62 are formed on the lead frame 50. The laminate 64 is integrated. When the hole 54 is formed in the metal base material layer 40 as shown in FIG. 3B due to the pressure applied at this time, the electrically insulating material enters the hole 54. Next, as shown in FIG. 3C, when the stacked body 64 has a hole 54, a portion corresponding to the hole 54 is shaved with a drill (not shown) to form a through hole 66. Next, as shown in FIG. 3D, copper plating 68 is performed on a necessary portion of the surface of the laminate 64. At this time, copper plating 68 is applied to the inner surface of the through hole 66, and the circuit layers 44 and 48 are electrically connected. Next, the pattern grooves 70 are formed by etching the circuit layers 44 and 48 on the front and back surfaces. Next, as shown in FIG. 3F, predetermined regions of the circuit layers 44 and 48 and the pattern groove 70 are covered with an insulating resist 72. Next, as shown in FIG. 3G, the circuit layer portion (circuit pattern 74) exposed without being covered with the resist 72 is gold-plated 76 to complete the first and second circuit layers 44 and 48. . Finally, as shown in FIG. 3H, the outer peripheral edge of the laminate 64 is cut away to complete the substrate 22.

  As shown in FIGS. 1A to 1C, the imaging unit 24 is laminated on the circuit layer (the circuit layer 48 shown in FIG. 1D) on one surface of the substrate 22 formed in this manner, and an adhesive or the like is used. Fixed. Further, the gold plating 76 of the circuit layer 48 (see FIG. 3H) and the electrode of the charge coupled device 32 are electrically connected by appropriate wiring (for example, wire bonding). Further, the circuit component 36 is connected to the gold plating 76 (see FIG. 3H) provided on the other surface of the substrate 22, whereby the charge coupled device 32 and the cable 34 are electrically connected via the connector 38. . The assembly 20 combined as described above is accommodated in the container 14.

  Thus, according to the X-ray image detector 10 described above, the main part of the substrate 22 is constituted by the metal base layer 40. And the metal base material layer 40 is more excellent in impact than ceramics. Therefore, even if some impact is applied, it will not be damaged or broken. Further, the substrate 22 and the X-ray image detector 10 can be formed thinner than the conventional X-ray image detector in which the base material layer is formed of ceramic. For example, as shown in FIGS. 8A and 8B, the X-ray shielding layer 100 and the substrate 102 are stacked adjacent to the imaging unit 24, and the substrate 102 is a ceramic layer 104 and a circuit layer (pattern layer) 106 disposed on both sides thereof. , 108 in the X-ray image detector of the present invention configured as shown in FIGS. 7A and 7B, the thickness of the substrate 22 is significantly reduced.

  Further, as shown in FIG. 1D, the substrate 22 shown in the first embodiment has a skeletal function for supporting the substrate 22, that is, both a skeleton function having an effect of supporting the assembly 20 and an X-ray shielding function. One metal substrate layer 40 provided, a first electrical insulating layer 42 and a first circuit layer 44 supported on one surface of the metal substrate layer 40, and the other surface of the metal substrate layer 40 The second electrical insulating layer 46 and the second circuit layer 48 are supported by each other. However, the present invention is not limited to the one having such a layer structure, and corresponds to the metal base layer 40 in the first embodiment described above, for example, the substrate 22 in the second embodiment shown in FIG. An insulating resin layer 76 made of an electrically insulating material, and an X-ray shielding layer which is a layer made of a metal having X-ray shielding properties arranged in contact with one surface of the insulating resin layer 76. 80 and a metal layer 78 disposed in contact with the other surface of the insulating resin layer 76, the X-ray shielding layer 80 is formed of silver, and the metal layer 78 is formed of carbon steel, whereby the former The X-ray shielding layer 80 may have an X-ray shielding function, and the latter metal layer 78 may have a skeleton function. When the base material layer thus separated is used, appropriate grooves and holes 82 and 84 are formed in the lead frames constituting the X-ray shielding layer 80 and the metal layer 78, respectively, and these are overlapped. Grooves and holes 82 and 84 corresponding to are overlapped.

  In Embodiment 2 shown in FIG. 4, the metal layer 78 is made of an alloy containing nickel such as the above-mentioned trade name 42 alloy other than carbon steel, an alloy containing tungsten such as silver, tungsten, copper tungsten, aluminum, Strength of alloys containing aluminum such as alloys of aluminum and copper and magnesium, alloys containing magnesium such as alloys of magnesium and zinc and aluminum, iron, stainless steel, chromium steel, alloys of copper and zinc, etc. You can use the metal you have. As an alloy of copper and zinc, an alloy of copper, zinc, and silicon (for example, trade name: Eco Brass) excellent in terms of workability, wear resistance, durability, and harmlessness can be suitably used. In the second embodiment, the X-ray shielding layer 80 is made of an alloy containing nickel such as the above-mentioned trade name 42 alloy, an alloy containing tungsten such as tungsten or copper tungsten, or an X-ray such as carbon steel, gold or lead. A metal having a shielding property can be used. Further, in the second embodiment, it is not necessary to insulate between the X-ray shielding layer 80 and the metal layer 78, and the electric insulating layer 76 interposed therebetween can be removed. In this case, if the X-ray shielding layer 80 and the metal layer 78 are insulated from the first circuit layer 44 and the second circuit layer 48 by the first electrical insulation layer 42 and the second electrical insulation layer 46. Good.

  In addition, the X-ray shielding layer 80 is disposed on the X-ray imaging unit side (the lower side in FIG. 4), and the metal layer 78 is disposed on the opposite side of the X-ray imaging unit. The X-ray shielding layer may be disposed far away from the line imaging unit.

  In both of the first embodiment and the second embodiment described above, the second circuit layer 48 is formed on the surface of the substrate 22 in contact with the imaging unit 24. The second circuit layer 48 contacts the imaging unit 24. The region may be used as a simple ground layer without forming a wiring there. Conversely, wiring may be formed on the second circuit layer 48 without forming wiring on the first circuit layer 44. Moreover, it is not necessary to form both the circuit layers 44 and 48 on the front and back of the substrate 22, and only one of them may be used.

  Furthermore, in Embodiment 1 and 2 mentioned above, the metal base material layer 40 and the X-ray shielding layer 78 can use arbitrary materials which can shield X-rays, for example, 42 alloy (trade name). Besides silver and carbon steel, silver, copper tungsten, etc. can also be used.

  Furthermore, as in the third embodiment shown in FIG. 5, a conductive metal layer constituting the conductive path 84 is formed on the surface of the substrate 22 (for example, the lower surface in the illustrated example), and the metal base layer 40 and the normal ground are formed. A potential reference point 86, which is referred to as “a”, may be connected to the potential reference point 86 via the copper plating 68 in the through hole 66, the conductive path 84, and the cable 34 (see FIGS. 1A and 1B). Good. In this case, the metal base layer 40 functions as an electromagnetic wave shielding layer or an electromagnetic wave interference reducing layer to prevent harmful electromagnetic waves from entering the circuit component 36 and the like, and is generated from the circuit component 36 and the charge coupled device 32 and the like. Electromagnetic waves can be prevented from adversely affecting other parts, external electric devices, and the like.

  And like Embodiment 4 shown to FIG. 6A and FIG. 6B, you may form the board | substrate 22 only with the metal layer (metal plate) 40 provided with the X-ray shielding function. In this case, a characteristic peculiar to metal is imparted to the substrate 22, and an X-ray image detector excellent in impact durability can be obtained. Further, the necessary electric circuit 86 does not need to be arranged behind the charge coupled device 32 and may be supported by a component other than the substrate 22. In this case, furthermore, there is no need to electrically insulate between the electric circuit 86 and the substrate 22 (metal layer 40).

As described above, the X-ray image detector according to the present invention satisfies the contradicting demands that it must be thin, small, and have impact durability.

FIG. 3 is a plan view of a part of the X-ray image detector according to the first embodiment. FIG. 2 is a cross-sectional view of the X-ray image detector shown in FIG. CC sectional drawing of the X-ray image detector shown in FIG. The expanded sectional view of the board | substrate of the X-ray image detector shown in FIG. The partial expansion perspective view of the metal lead frame which comprises a board | substrate. FIG. 2 is an enlarged cross-sectional view showing a procedure for manufacturing the substrate of the X-ray image detector shown in FIG. 1 and before each layer constituting the substrate is pressed. It is a figure which shows the procedure which manufactures the board | substrate of an X-ray image detector with FIG. 3A, and is an expanded sectional view after pressing each layer which comprises a board | substrate. FIG. 4 is an enlarged cross-sectional view showing a step of manufacturing a substrate of an X-ray image detector together with FIG. 3A and FIG. It is a figure which shows the procedure which manufactures the board | substrate of an X-ray image detector with FIG. 3A-FIG. 3C, and is an expanded sectional view of the state which coat | covered the surface with gold plating. It is a figure which shows the procedure which manufactures the board | substrate of an X-ray image detector with FIG. 3A-FIG. 3D, and is an expanded sectional view after forming the circuit pattern groove | channel in a circuit layer. It is a figure which shows the procedure which manufactures the board | substrate of an X-ray image detector with FIG. 3A-FIG. 3E, and is an expanded sectional view after removing the resist of the surface partially. It is a figure which shows the procedure which manufactures the board | substrate of an X-ray image detector with FIG. 3A-FIG. 3F, and is an expanded sectional view after coat | covering the location which deleted the resist with gold plating. It is a figure which shows the procedure which manufactures the board | substrate of an X-ray image detector with FIG. 3A-FIG. 3G, and is an expanded sectional view after excising the circumference | surroundings of a board | substrate. FIG. 4 is an enlarged cross-sectional view of a substrate used in the X-ray image detector according to the second embodiment. FIG. 6 is an enlarged cross-sectional view of a substrate used in the X-ray image detector according to the third embodiment. FIG. 6 is an enlarged cross-sectional view of a substrate used in the X-ray image detector according to the fourth embodiment. FIG. 6B is a cross-sectional view of an X-ray image detector provided with the substrate of FIG. 6A. 1 is a cross-sectional view of an X-ray image detector according to the present invention. The expanded sectional view of the board | substrate in the X-ray image detector of FIG. 7A. Sectional drawing of the conventional X-ray image detector. The expanded sectional view of the board | substrate in the X-ray image detector of FIG. 8A.

Explanation of symbols

10: X-ray image detector 12: Detection surface 14: Container 16.18: Container part 20: Assembly 22: Substrate 24: Imaging unit 26: Electrical connection unit 28: Phosphor 30: Light propagation element 32: Charge coupled element 34 : Cable 36: circuit component 38: connector 40: metal base layer 42: first electrical insulation layer 44: first circuit layer 46: second electrical insulation layer 48: second circuit layer 50: lead frame 52 : Groove 54: Hole 56, 58: Insulating material layer (prepreg)
60, 62: conductive metal layer 64: laminate 66: through hole 68: copper plating 70: pattern groove 72: resist 74: circuit pattern 76: gold plating 78: metal layer 80: X-ray shielding layer 82: hole

Claims (11)

In an X-ray image detector in which an X-ray imaging unit for converting an X-ray image into an electrical signal is contained in a container,
A substrate that supports the X-ray imaging unit,
A metal base layer having an X-ray shielding function;
A circuit layer for transmitting a signal from the X-ray imaging unit;
An X-ray image detector comprising an electrical insulating layer held in contact with the base material layer and the circuit layer.   2. The X-ray image detection according to claim 1, wherein the base material layer is formed of any one of an alloy containing nickel, silver, tungsten, an alloy containing tungsten, or carbon steel. vessel.   The X-ray image detector according to claim 1, wherein the base material layer includes a metal X-ray shielding layer and a metal layer.   The said base material layer consists of a metal X-ray shielding layer, a metal layer, and the electrical-insulation layer pinched | interposed between the said X-ray shielding layer and a metal layer of Claims 1-3 characterized by the above-mentioned. The X-ray image detector in any one.   The X-ray shielding layer is formed of any one of an alloy containing nickel, silver, tungsten, an alloy containing tungsten, gold, lead, or carbon steel. X-ray image detector described in 1.   The metal layer is an alloy containing nickel, silver, tungsten, an alloy containing tungsten, aluminum, an alloy containing aluminum, an alloy containing magnesium, iron, carbon steel, stainless steel, chromium steel, copper and zinc The X-ray image detector according to claim 2, wherein the X-ray image detector is formed of any one of the alloys.   6. The X-ray image detector according to claim 1, further comprising a conductive path connecting the metal base layer having the X-ray shielding function to a potential reference point.   An X-ray image detector in which an X-ray imaging unit for converting an X-ray image into an electric signal is housed in a container, wherein the substrate supporting the X-ray imaging unit is made of a metal having an X-ray shielding function. . In a method of manufacturing a substrate that supports the X-ray imaging unit in an X-ray image detector that houses an X-ray imaging unit that converts an X-ray image into an electrical signal in a container,
A method of manufacturing a substrate, wherein an electrically insulating material is sandwiched between a metal layer having X-ray shielding properties and a conductive metal layer to sandwich each other, and the conductive metal layer is partially removed to form a circuit. In a method of manufacturing a substrate that supports the X-ray imaging unit in an X-ray image detector that houses an X-ray imaging unit that converts an X-ray image into an electrical signal in a container,
An X-ray shielding metal layer and a metal layer are adjacent to each other, and an X-ray shielding metal layer or an electrically insulating material is sandwiched between the metal layer and the conductive metal layer and fixed to each other. A substrate manufacturing method in which a conductive metal layer is partially removed to form a circuit. In a method of manufacturing a substrate that supports the X-ray imaging unit in an X-ray image detector that houses an X-ray imaging unit that converts an X-ray image into an electrical signal in a container,
An electrically insulating material is sandwiched between a metal layer having an X-ray shielding property and the metal layer having an X-ray shielding property, or an electrically insulating material is disposed between the metal layer having an X-ray shielding property or the metal layer and a conductive metal. A method for manufacturing a substrate in which a circuit is formed by sandwiching and fixing them all together and partially removing the conductive metal layer.

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