JP6602255B2 - Electronic substrate for medical equipment - Google Patents

Description

  The present invention relates to an electronic substrate for medical equipment.

Since medical devices are sterilized, electronic substrates for medical devices are required to have heat resistance, gas permeation resistance, chemical resistance, and the like corresponding to sterilization.
As a technology related to a semiconductor device with improved environmental resistance, for example, Patent Document 1 describes a resin-encapsulated semiconductor device in which a semiconductor chip is encapsulated with resin in order to improve the durability of an electronic component. In this resin-encapsulated semiconductor device, the semiconductor chip is encapsulated with a cured product of a composition in which an inorganic filler is blended with a thermosetting epoxy resin. In Patent Document 1, since the linear expansion coefficient of the cured body is reduced by adding a filler to the thermosetting epoxy resin, warpage after sealing is reduced, and reliability after mounting is improved. Are listed.

Japanese Patent No. 3406703

However, the conventional techniques as described above have the following problems.
As a sterilization process in a medical device, for example, an autoclave sterilization process is used. The autoclave sterilization process is, for example, a severe sterilization process in which a medical device is exposed to high-temperature and high-pressure steam at about 130 ° C. and 2 atm. In autoclave sterilization, the entire electronic board on which electronic components are mounted is subjected to severe thermal stress and exposed to a high humidity environment.
Therefore, for example, it is conceivable to apply a resin sealing technique such as that of Patent Document 1 to the entire electronic component on the medical device electronic substrate. In this case, if the inorganic filler is increased to the extent that it can withstand a wide range of temperature changes, there is a problem that it becomes difficult to apply the sealing material because the viscosity of the sealing material increases. Even if the sealing material can be applied, there is a problem that gaps or bubbles may be formed between the electronic component and the electronic circuit board and the sealing material, and sufficient adhesion may not be obtained. . If the sealing material is not in close contact with the electronic component and the electronic circuit board, the sealing material may be peeled off or high-temperature water vapor may touch the electronic component, which may impair reliability as a medical device.
When the filler is reduced in order to improve the adhesion to the electronic component and the electronic circuit board, the linear expansion coefficient of the cured material of the sealing material increases. In this case, there is a problem that the electronic component may be damaged because stress is applied to the electronic component due to the expansion and contraction of the cured material of the sealing material generated by the sterilization cycle.

  This invention is made | formed in view of the above problems, and it aims at providing the electronic substrate for medical devices which can improve the durability with respect to the sterilization process by heating.

In order to solve the above problems, an electronic board for medical devices according to a first aspect of the present invention includes an electronic circuit board having a first linear expansion coefficient, and a plurality of electronic components mounted on the electronic circuit board. A sealing material having a second linear expansion coefficient larger than the first linear expansion coefficient and being fixed to the electronic circuit board and the plurality of electronic components in a state of covering the plurality of electronic components; The sealing member having a third linear expansion coefficient smaller than the second linear expansion coefficient and covering the plurality of electronic components with the sealing material sandwiched between the electronic circuit board and the plurality of electronic components. with a thermal expansion inhibiting member which is secured to the timber, the said thermal expansion inhibiting member that have a least one of the plurality of recesses and a plurality of convex portions on the surface to stick to the sealing material.

A second aspect of the medical device for electronic board of the present invention includes an electronic circuit board having a first linear expansion coefficient, and a plurality of electronic components mounted on the electronic circuit board, said first linear expansion coefficient A sealing material that has a larger second linear expansion coefficient than the first electronic circuit board and covers the plurality of electronic components and is fixed to the electronic circuit board and the plurality of electronic components, and the second linear expansion coefficient. A thermal expansion that has a third coefficient of linear expansion smaller than that of the electronic circuit board and that covers the plurality of electronic components with the sealing material interposed therebetween. includes a restraining member, wherein the thermal expansion inhibiting member is have a plurality of through holes opening on the surface to stick to the sealing material.

A third aspect of the medical device for electronic board of the present invention includes an electronic circuit board having a first linear expansion coefficient, and a plurality of electronic components mounted on the electronic circuit board, said first linear expansion coefficient A sealing material that has a larger second linear expansion coefficient than the first electronic circuit board and covers the plurality of electronic components and is fixed to the electronic circuit board and the plurality of electronic components, and the second linear expansion coefficient. A thermal expansion that has a third coefficient of linear expansion smaller than that of the electronic circuit board and that covers the plurality of electronic components with the sealing material interposed therebetween. A suppression member, wherein the thermal expansion suppression member has at least a step formed on a surface fixed to the sealing material, and at least one of the plurality of electronic components and the thermal expansion suppression member The layer thickness of the sealing material between the at least one electronic part Wherein at least the layer thickness of the sealing material in between the electronic circuit board of the non-mounting region in the outer peripheral portion and the thermal expansion inhibiting member.
In the electronic substrate for medical devices according to each aspect described above, the thermal expansion suppressing member may have a base layer that improves adhesion to the sealing material on a surface that is fixed to the sealing material.

  According to the electronic substrate for medical equipment of the present invention, there is an effect that durability against sterilization treatment by heating can be improved.

It is a typical top view which shows the structural example of the electronic substrate for medical devices of the 1st Embodiment of this invention. It is AA sectional drawing in FIG. It is a typical top view which shows the structural example of the electronic substrate for medical devices of the 2nd Embodiment of this invention. It is BB sectional drawing in FIG. It is a typical top view which shows the structural example of the electronic substrate for medical devices of the modification (1st modification) of the 2nd Embodiment of this invention. It is CC sectional drawing in FIG. It is a typical longitudinal cross-sectional view which shows the structural example of the electronic substrate for medical devices of the 3rd Embodiment of this invention. It is a schematic diagram explaining the effect | action at the time of replacing a thermal expansion suppression member with a flat plate. It is a typical expanded sectional view of the thermal expansion suppression member used for the electronic substrate for medical devices of the modification (2nd modification-5th modification) of the 1st Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
A medical device electronic substrate according to a first embodiment of the present invention will be described.
FIG. 1 is a schematic plan view illustrating a configuration example of an electronic substrate for medical devices according to the first embodiment of the present invention. 2 is a cross-sectional view taken along line AA in FIG.

1 is mounted with a plurality of electronic components constituting an electronic circuit used in a medical device (not shown). The medical device in which the medical device electronic substrate 11 is used is not particularly limited. Examples of medical devices in which the electronic device 11 for medical devices is used include, for example, an endoscope device, a treatment tool, an ultrasonic knife, a laser knife, a dental LED illumination, surgical sensors (such as a pulse oximeter), and the like. Is mentioned.
Examples of medical devices for which the electronic device 11 for medical devices is particularly suitable include medical devices that are subjected to heat sterilization such as autoclave sterilization.
As shown in FIGS. 1 and 2, the medical device electronic board 11 includes a circuit board 1 (electronic circuit board), electronic components 2A, 2B, and 2C, a sealing material 3 (see FIG. 2), and a thermal expansion suppressing member. 4 is provided.

On the circuit board 1, wiring patterns (not shown) for mounting electronic components 2A, 2B, and 2C described later are formed.
As the material of the circuit board 1, a material that is less likely to thermally expand than the sealing material 3 described later is used. The linear expansion coefficient α1 (first linear expansion coefficient) of the circuit board 1 is smaller than the linear expansion coefficient α2 (second linear expansion coefficient) of the sealing material 3 described later. For example, as a material of the circuit board 1, a glass epoxy board (FR-4), a ceramic board, a semiconductor board (Si), or the like may be used.
For example, the linear expansion coefficient of the glass epoxy substrate is about 13 × 10 ⁻⁶ (K ⁻¹ ) although it depends on the type. The linear expansion coefficient of the ceramic substrate is about 7.3 × 10 ⁻⁶ (K ⁻¹ ) although it depends on the type. The linear expansion coefficient of the Si substrate is about 2.4 × 10 ⁻⁶ (K ⁻¹ ) although it depends on the type.

The board structure of the circuit board 1 is not particularly limited. For example, the circuit board 1 may be a single-sided board or a double-sided board. The circuit board 1 may be a single layer board or a multilayer board.
FIG. 1 illustrates an example in which the circuit board 1 has a rectangular shape in plan view, but the outer shape of the circuit board 1 is not limited to a rectangle.

The electronic components 2A, 2B, and 2C are mounted on a wiring pattern (not shown) of the circuit board 1.
The types of electronic components 2A, 2B, and 2C are not particularly limited as long as they are components that constitute a part of an electronic circuit used in a medical device (not shown). For example, the electronic components 2A, 2B, and 2C may be ICs, capacitors, chip resistors, and the like.
FIG. 1 shows an example in which there are three electronic components 2A, 2B, and 2C on the electronic substrate 11 for medical equipment, but this is an example. As the number of electronic components of the electronic substrate 11 for medical equipment, an appropriate number of two or more may be used according to a required electronic circuit.

Hereinafter, as an example, the electronic components 2A, 2B, and 2C will be described as surface-mount ICs.
The electronic components 2A, 2B, 2C are provided with leads extending from the respective packages. In the electronic components 2A, 2B, and 2C, each lead is soldered to a land pattern (not shown) on the circuit board 1.
The electronic components 2 </ b> A, 2 </ b> B, and 2 </ b> C are mounted on the circuit board 1, and the component upper surfaces 2 a, 2 b, and 2 c are arranged substantially parallel to the board surface 1 a of the circuit board 1.
In FIG. 2, as an example, the mounting heights of the component upper surfaces 2a, 2b, and 2c with respect to the substrate surface 1a are h1.

The sealing material 3 is a member that seals the electronic components 2A, 2B, and 2C on the circuit board 1.
The sealing material 3 is disposed so as to cover the substrate surface 1a of the circuit board 1 and the surfaces (including the surfaces of the leads) of the electronic components 2A, 2B, and 2C. That is, the lower surface 3b of the sealing material 3 is in close contact with the substrate surface 1a of the circuit board 1, and when the distance from the lower surface 3b to the upper surface 3a of the sealing material 3 is a layer thickness h2, h2> h1. In the present embodiment, a layered portion of the sealing material 3 having a thickness of h2-h1 is formed on the component upper surfaces 2a, 2b, and 2c of the electronic components 2A, 2B, and 2C.
The sealing material 3 is filled with no gap between the lower surfaces of the electronic components 2A, 2B, and 2C and the substrate surface 1a.
The sealing material 3 that contacts the substrate surface 1a of the circuit board 1 and the surfaces of the electronic components 2A, 2B, and 2C is solidified in a state of being fixed to the substrate surface 1a of the circuit board 1 and the surfaces of the electronic components 2A, 2B, and 2C. ing.

The sealing material 3 has the above-described linear expansion coefficient α2 (α2> α1), can seal the electronic components 2A, 2B, and 2C, and can be used for sterilization and the like. A material having heat resistance that can withstand the heating temperature applied to 11 and electrical insulation is used.
Furthermore, the linear expansion coefficient α2 of the sealing material 3 is larger than the linear expansion coefficient α3 (third linear expansion coefficient) of the thermal expansion suppressing member 4 described later.
It is more preferable that the sealing material 3 is made of a material that does not easily penetrate moisture or gas used for sterilization.
Examples of the resin material that can be used for the sealing material 3 include an epoxy resin, a silicone resin, and a urethane resin. The resin material used for the sealing material 3 may be a thermosetting resin.
Examples of the epoxy resin-based material that can be suitably used for the sealing material 3 include coating agents 1570-2, 1057, 1033, and 1020 (trade name; manufactured by NAMICS Co., Ltd.).
Other examples of the epoxy resin-based material that can be suitably used for the sealing material 3 include an impact-resistant (heat cycle) two-pack type epoxy resin EX-565 / H-565 (trade name; manufactured by Sanyu Rec Co., Ltd.) ).
These epoxy resins have high heat resistance and are useful for high temperature sterilization treatment.

An appropriate additive may be added to the resin material used for the sealing material 3. Examples of the additive include a filler, a colorant, a coupling agent, and an antioxidant. However, when an additive is included, the content is set such that the viscosity does not become excessively high so as not to lower the workability during coating.
As will be described later, in this embodiment, since the thermal expansion of the sealing material 3 is suppressed by the thermal expansion suppressing member 4, the filler for the purpose of reducing the linear expansion coefficient is not added to the sealing material 3. Also good.

As shown in FIGS. 1 and 2, the thermal expansion suppressing member 4 is fixed to the sealing material 3 while covering the electronic components 2 </ b> A, 2 </ b> B, and 2 </ b> C with the sealing material 3 sandwiched between the circuit board 1. ing. In the present embodiment, the fixing surface 4 b of the thermal expansion suppressing member 4 is fixed to the upper surface 3 a of the sealing material 3.
As shown in FIGS. 1 and 2, in the present embodiment, the outer shape of the thermal expansion suppressing member 4 in plan view matches the outer shape of the sealing material 3 in plan view. However, the thermal expansion suppressing member 4 may have a shape different from the planar view of the sealing material 3 as long as it is a continuous member that covers at least the entirety of the electronic components 2A, 2B, and 2C. For example, a part of the sealing material 3 may be formed outside the outer shape of the thermal expansion suppressing member 4. The entire sealing material 3 may be fixed inside the outer shape of the thermal expansion suppressing member 4.
As described above, the linear expansion coefficient α3 of the thermal expansion suppressing member 4 has a relationship of α3 <α2. It is more preferable that the linear expansion coefficient α3 of the thermal expansion suppressing member 4 and the linear expansion coefficient α1 of the circuit board 1 are approximately the same. However, a difference that does not cause damage to the wiring patterns of the electronic components 2A, 2B, and 2C and the circuit board 1 due to thermal deformation caused by a sterilization cycle to be described later is acceptable.

The shape of the thermal expansion suppressing member 4 is not particularly limited as long as it can be fixed to the sealing material 3. The thermal expansion suppressing member 4 shown in FIG. 2 uses a flat plate as an example.
The material of the thermal expansion suppressing member 4 is not particularly limited as long as the above-described condition of the linear expansion coefficient α3 is satisfied. For example, suitable materials for the thermal expansion suppressing member 4 include stainless steel (linear expansion coefficient: 17.3 × 10 ⁻⁶ (K ⁻¹ )), aluminum alloy (linear expansion coefficient: 23.5 × 10 ⁻⁶ ( K- ¹ )) and other metals, ceramics, or resins whose linear expansion coefficient is adjusted by reinforcing fibers or the like may be used. Furthermore, the thermal expansion suppressing member 4 may be composed of a composite material obtained by appropriately combining these materials.
Examples of the ceramic suitable for the thermal expansion suppressing member 4 include oxide ceramics such as SiO ₂ , Al ₂ O ₃ , ZrO ₂ , and TiO ₂ . Since these oxide ceramics have good adhesion to the sealing material 3, high durability is obtained.
Examples of a resin material suitable for the thermal expansion suppressing member 4 include a glass epoxy substrate. For example, a cloth-like reinforcing material knitted with glass fiber, metal fiber, or the like has a direction in which it is easily deformed depending on the knitted structure, and thus anisotropy of the thermal expansion coefficient is likely to occur. Furthermore, since these cloth-like reinforcing materials are easily buckled, they are weaker in compression in the fiber direction than in the fiber direction. For this reason, when the compressing stress is applied along the fixing surface 4b of the thermal expansion suppressing member 4 as in the case where the sealing material 3 contracts at a low temperature, the sealing material 3 is easily deformed. For these reasons, a resin material including a cloth-like reinforcing material is not suitable as the thermal expansion suppressing member 4.
However, when it has a structure in which a plurality of fabrics with different fiber directions are stacked like a glass epoxy substrate, illegal use of the linear expansion coefficient and rigidity is reduced. Can do.
When a glass epoxy substrate made of the same material as the circuit board 1 is used as the thermal expansion suppressing member 4, α1 = α3, and thus warp deformation of the medical device electronic substrate 11 due to thermal expansion is suppressed.

When the difference between the linear expansion coefficient α3 of the thermal expansion suppressing member 4 and the linear expansion coefficient α1 of the circuit board 1 is large, the rigidity of the thermal expansion suppressing member 4 is made higher than the rigidity of the circuit board 1. Is more preferable. The rigidity of the thermal expansion suppressing member 4 is set such that thermal deformation of the medical device electronic substrate 11 due to a sterilization cycle, which will be described later, does not cause damage to the wiring patterns of the electronic components 2A, 2B, 2C and the circuit board 1.
The rigidity required for the thermal expansion suppressing member 4 can be calculated by performing a thermal deformation analysis of the medical device electronic substrate 11.

The material of the thermal expansion suppressing member 4 may be a material that does not permeate moisture or gas used for sterilization. In this case, the permeation resistance with respect to moisture or gas used for sterilization treatment is improved in the region fixed to the sealing material 3.
The material of the thermal expansion suppressing member 4 may be a conductive material. In this case, since the thermal expansion suppressing member 4 can be used as a conductor for electromagnetic wave shielding, it is possible to realize good EMC characteristics.
As a material of the thermal expansion suppressing member 4, it is more preferable to use stainless steel in that it does not permeate moisture or gas used for sterilization, has conductivity, and provides high rigidity.

The medical device electronic substrate 11 having such a configuration is manufactured, for example, as follows.
First, electronic components 2A, 2B, and 2C are soldered to the substrate surface 1a of the circuit board 1.
Thereafter, a coating liquid that becomes the sealing material 3 after curing is applied to the area covering the electronic components 2A, 2B, and 2C on the substrate surface 1a.
The application method is not particularly limited. For example, a coating method may be used in which a coating frame is disposed on the substrate surface 1a so as to surround the electronic components 2A, 2B, and 2C, and then a coating liquid is discharged inside the coating frame by a dispenser. In this case, even if the viscosity of the coating liquid is low, the coating liquid can be applied to a predetermined height that reliably covers the electronic components 2A, 2B, and 2C. In the case of this embodiment, the height of the coating frame is higher than the layer thickness of the sealing material 3. The plan view shape of the inner peripheral surface of the coating frame is equal to the formation range of the sealing material 3 and the outer shape of the thermal expansion suppressing member 4.
As the coating frame, for example, a resin frame formed by curing a resin having a good releasability from the sealing material 3 may be used. For example, when the sealing material 3 is made of an epoxy resin, a silicone resin frame may be used as the coating frame.

  Since the coating liquid can flow inside the coating frame, for example, it can easily penetrate into the gap between the electronic components 2A, 2B, and 2C and the substrate surface 1a. For this reason, a coating liquid adheres to the whole surface of electronic components 2A, 2B, and 2C.

Thereafter, the thermal expansion suppressing member 4 is placed on the coating liquid. For example, when the above-described coating frame is used, the thermal expansion suppressing member 4 is placed so as to cover the entire surface of the coating liquid in the coating frame by being inserted from above into the inner peripheral surface of the coating frame. Is done. The thermal expansion suppressing member 4 presses the surface of the coating liquid by its own weight. Thereby, the adhering surface 4b of the thermal expansion suppressing member 4 is in close contact with the surface of the coating liquid.
The thermal expansion suppressing member 4 is positioned with respect to the coating liquid in a state of being fitted to the coating frame.
If the outer shape of the thermal expansion suppressing member 4 in plan view is larger than the upper opening of the application frame, for example, after applying the coating liquid so as to rise slightly from the upper end of the application frame, the upper end of the application frame The thermal expansion suppressing member 4 may be stacked on the surface.

Thus, when the thermal expansion suppressing member 4 is placed on the coating liquid, the coating liquid is cured.
As a method for curing the coating liquid, an appropriate curing method is used according to the material of the coating liquid. For example, when the coating liquid is a thermosetting resin, the coating liquid is heated to a temperature at which the thermosetting resin is cured.
When the coating liquid is cured, the sealing material 3 is formed. The lower surface 3 b of the sealing material 3 is fixed to the substrate surface 1 a of the circuit board 1. The upper surface 3 a of the sealing material 3 is fixed to the fixing surface 4 b of the thermal expansion suppressing member 4.
When the curing of the coating liquid is completed, the coating frame is removed.
In this manner, the medical device electronic substrate 11 is manufactured.

The operation of the medical device electronic substrate 11 will be described.
The sealing material 3 is cured between the substrate surface 1a of the circuit board 1 and the fixing surface 4b of the thermal expansion suppressing member 4 in a state of being in close contact with the entire surface of the electronic components 2A, 2B, and 2C. As a result, the sealing material 3 seals the electronic components 2A, 2B, and 2C on the substrate surface 1a. Since the sealing material 3 is made of a material that can withstand sterilization treatment by heating, the electronic components 2A, 2B, and 2C and the substrate surface 1a covered with the sealing material 3 are also sealed by the sealing material 3 during the sterilization processing. Protected. For example, when the sealing material 3 is a material having heat resistance and permeation resistance such as an epoxy resin, it is possible to prevent permeation of water vapor even in a high temperature and high humidity environment such as autoclave sterilization.

When sterilization by heating is performed, each member constituting the medical device electronic substrate 11 is thermally expanded. In the sterilization process, the entire electronic substrate 11 for medical devices is heated to a substantially constant temperature, so that each member thermally expands according to the respective linear expansion coefficient.
Here, the electronic components 2A, 2B, 2C soldered to the circuit board 1 are smaller than the circuit board 1, the sealing material 3, and the thermal expansion suppressing member 4, and have a linear expansion coefficient α2 of the sealing material 3. In comparison, the coefficient of linear expansion is also small, so it may be considered that the circuit board 1 moves together.

The circuit board 1, the sealing material 3, and the thermal expansion suppressing member 4 are fixed and integrated with each other at the interface of the layers in a state of being stacked substantially parallel to each other (including the parallel case). The circuit board 1, the sealing material 3, and the thermal expansion suppressing member 4 try to extend in a direction (hereinafter referred to as a plane direction) orthogonal to the plate thickness direction (layer thickness direction) according to the respective linear expansion coefficients. To do.
However, among the circuit board 1, the sealing material 3, and the thermal expansion suppressing member 4, the sealing material 3 having the largest linear expansion coefficient α 2 is used as the circuit board 1 and the thermal expansion suppressing member 4 having a smaller linear expansion coefficient. It is stuck. The deformation in the surface direction of the sealing material 3 is restrained by the circuit board 1 and the thermal expansion suppressing member 4. That is, the amount of thermal expansion in the surface direction of the lower surface 3b and the upper surface 3a of the sealing material 3 fixed to the circuit board 1 and the thermal expansion suppressing member 4 respectively is the board surface 1a corresponding to the linear expansion coefficients α1 and α3, respectively. It is equal to the amount of thermal expansion in the surface direction of the flat surface forming surface 4b.

For example, when the sealing material 3 is not constrained by the thermal expansion suppressing member 4, since α2> α1, a stress that causes warpage deformation in which the substrate surface 1a becomes convex acts on the circuit board 1 from the sealing material 3. To do. For this reason, stress also acts on the wiring pattern on the substrate surface 1a and the electronic components 2A, 2B, and 2C. This stress load disappears when sterilization is completed.
As described above, when the thermal expansion suppressing member 4 is not provided, when the sterilization process is repeated, the wiring pattern on the substrate surface 1a and the electronic components 2A, 2B, and 2C are repeatedly subjected to stress. As a result, the wiring pattern may be fatigued and disconnected, or the electronic components 2A, 2B, and 2C may be damaged.
When such repeated stress acts, the sealing material 3 may be separated from the circuit board 1 and the electronic components 2A, 2B, and 2C to generate a gap. In this case, the sealing state by the sealing material 3 is impaired, and the moisture and the drug solution are likely to penetrate into the sealing material 3. The wiring pattern and the electronic components 2A, 2B, 2C may corrode the wiring pattern and the electronic components 2A, 2B, 2C due to moisture and chemicals that have penetrated into the sealing material 3.

However, in the medical device electronic substrate 11 of this embodiment, the thermal expansion suppressing member 4 is fixed to the upper surface 3 a of the sealing material 3. Since α3 <α2, thermal expansion in the surface direction of the upper surface 3a of the sealing material 3 is suppressed. As a result, the warp deformation of the circuit board 1 is suppressed, and the stress load on the wiring pattern and the electronic components 2A, 2B, and 2C on the board surface 1a is also reduced.
As a result, the possibility that the wiring pattern is fatigued and disconnected or the electronic components 2A, 2B, and 2C are damaged is reduced. Furthermore, even if the sterilization process is repeated, the sealing state by the sealing material 3 is also kept good, so that the corrosion of the wiring pattern and the electronic components 2A, 2B, 2C is suppressed.
Thus, according to the medical device electronic substrate 11, durability against sterilization treatment by heating is improved.

When the thermal expansion suppressing member 4 is made of a material that does not allow moisture or gas used for sterilization to penetrate, the permeation resistance to the moisture or gas used for sterilization is improved in the region fixed to the sealing material 3. To do. For this reason, the durability of the electronic substrate 11 for medical devices can be further improved.
When the thermal expansion suppressing member 4 includes a metal having conductivity, the thermal expansion suppressing member 4 can be used as a conductor for electromagnetic wave shielding.
When a highly rigid material such as a stainless steel plate is used as the material of the thermal expansion suppressing member 4, the thickness of the thermal expansion suppressing member 4 can be reduced, and thus the electronic substrate 11 for medical equipment can be reduced in weight. Can do.

[Second Embodiment]
A medical device electronic substrate according to a second embodiment of the present invention will be described.
FIG. 3 is a schematic plan view illustrating a configuration example of an electronic substrate for medical devices according to the second embodiment of the present invention. 4 is a cross-sectional view taken along the line BB in FIG.

As shown in FIGS. 3 and 4, the medical device electronic substrate 12 of the present embodiment is replaced with the thermal expansion suppressing member 4 and the sealing material 3 of the medical device electronic substrate 11 of the first embodiment, A thermal expansion suppressing member 24 and a sealing material 23 are provided.
The medical device electronic substrate 12 can be used in place of the medical device electronic substrate 11 in the medical device in which the medical device electronic substrate 11 of the first embodiment is used.
Hereinafter, a description will be given centering on differences from the first embodiment.

The thermal expansion suppressing member 24 is configured by forming a plurality of through holes 24c penetrating in the plate thickness direction in the thermal expansion suppressing member 4 in the first embodiment. The through hole 24 c is a recess with respect to the fixing surface 4 b of the thermal expansion suppressing member 24.
Similar to the first embodiment, the outer shape in plan view of the thermal expansion suppressing member 24 may be the same as, larger or smaller than the outer shape in plan view of the sealing material 23 described later. As an example, FIGS. 3 and 4 show an example in which the outer shape of the thermal expansion suppressing member 24 in plan view is smaller than the outer shape of the sealing material 23 in plan view. When the thermal expansion suppressing member 24 has such a size, the outer peripheral portion of the thermal expansion suppressing member 24 is buried in the sealing material 23. For this reason, the edge of the outer peripheral part of the thermal expansion suppression member 24 is covered with the sealing material 23.

The shape and number of the through holes 24c are not limited. The through holes 24c shown in FIG. 3 are, for example, a large number of circular holes arranged in a square lattice with an equal pitch. As the number of the through holes 24c increases, the adhesion to the sealing material 3 increases, so that the effect of suppressing thermal expansion of the sealing material 3 described later increases. However, if the number of the through holes 24c is too large, the rigidity of the thermal expansion suppressing member 24 is lowered. When the rigidity of the thermal expansion suppressing member 24 is lowered, there is a possibility that the warp deformation of the medical device electronic substrate 12 when the sealing material 3 is thermally deformed as described later cannot be sufficiently suppressed. For this reason, the number of through holes 24c is set to an appropriate number in consideration of the rigidity required for the thermal expansion suppressing member 24.
The arrangement pitch and the hole diameter of the through holes 24c are smaller than the length in the short direction of the outer shape of the electronic components 2A, 2B, and 2C in plan view. However, the hole diameter of each through-hole 24c is a size in which the material which forms the sealing material 23 mentioned later can approach.
As the thermal expansion suppressing member 24, for example, a punching metal, a ceramic molded product, a resin molded product, or the like may be used.

The sealing material 23 is made of the same material as the sealing material 3 of the first embodiment. However, the sealing material 3 in the first embodiment is sandwiched between the circuit board 1 and the thermal expansion suppressing member 4, whereas the sealing material 23 penetrates the thermal expansion suppressing member 24. The difference from the first embodiment is that the hole 24c enters the inside of the hole 24c.
FIG. 4 shows an example in which the upper surface 23a of the sealing material 23 in the through hole 24c is the same height as the outer surface 4a of the thermal expansion suppressing member 24. However, the upper surface 23a of the sealing material 23 in the through hole 24c may be lower than the outer surface 4a or higher than the outer surface 4a as long as it is higher than the fixing surface 4b of the thermal expansion suppressing member 24. When the upper surface 23a of the sealing material 23 in the through hole 24c is higher than the outer surface 4a, a part of the sealing material 23 may protrude around the opening of the through hole 24c.

  The medical device electronic substrate 12 having such a configuration is manufactured in the same manner as the medical device electronic substrate 11 of the first embodiment.

In the medical device electronic substrate 12 of the present embodiment, the sealing material 23 is in close contact with the entire surface of the electronic components 2A, 2B, and 2C in the same manner as the sealing material 3 in the first embodiment. The substrate 1 is cured between the substrate surface 1 a of the substrate 1 and the fixing surface 4 b of the thermal expansion suppressing member 24.
For this reason, the sealing material 23 is similar to the sealing material 3 in the first embodiment, and the substrate surface 1a covered with the electronic components 2A, 2B, and 2C and the sealing material 23 during the sterilization process. Can be protected.
Since the thermal expansion suppressing member 24 is made of the same material as that of the thermal expansion suppressing member 4 in the first embodiment, the warp of the medical device electronic board 12 when heated as in the first embodiment. Deformation is suppressed. As a result, the warp deformation of the circuit board 1 is suppressed, and the stress load on the wiring pattern and the electronic components 2A, 2B, and 2C on the board surface 1a is reduced. Furthermore, even if the sterilization process is repeated, the sealing state by the sealing material 23 is also kept good, so that the progress of corrosion of the wiring pattern and the electronic components 2A, 2B, 2C is suppressed.
Thus, according to the medical device electronic substrate 12, durability against sterilization treatment by heating is improved.

[First Modification]
A medical device electronic substrate according to a modification (first modification) of the second embodiment of the present invention will be described.
FIG. 5 is a schematic plan view showing a configuration example of an electronic board for medical devices according to a modified example (first modified example) of the second embodiment of the present invention. 6 is a cross-sectional view taken along the line CC in FIG.

As shown in FIGS. 5 and 6, the medical device electronic substrate 13 of the present modification includes a sealing material 33 instead of the sealing material 23 of the medical device electronic substrate 12 of the first embodiment. .
The medical device electronic substrate 13 can be used in place of the medical device electronic substrate 11 in the medical device in which the medical device electronic substrate 11 of the first embodiment is used.
Hereinafter, a description will be given focusing on differences from the second embodiment.

The sealing material 33 is different from the sealing material 23 in the second embodiment in that the sealing material 33 penetrates into the through hole 24c and covers the entire outer surface 4a of the thermal expansion suppressing member 24.
The sealing material 33 of this modification also seals the thermal expansion suppressing member 24 inside.
This modification is an example in which the upper surface 33 a of the sealing material 33 covers the outer surface 4 a of the thermal expansion suppressing member 24.

  The electronic substrate 13 for medical equipment having such a configuration is the second embodiment except that the coating liquid for forming the sealing material 33 is applied so as to cover the outer surface 4a of the thermal expansion suppressing member 24. It is manufactured in the same manner as the electronic substrate 12 for medical devices.

According to the medical device electronic substrate 13 of the present modification, the durability against sterilization treatment by heating is improved in the same manner as the medical device electronic substrate 12 of the second embodiment.
Furthermore, according to the medical device electronic substrate 13 of this modification, the sealing material 33 also seals the thermal expansion suppressing member 24. If the material of the sealing material 33 is a material having resistance to sterilization processing, the thermal expansion suppressing member 24 is protected by the sealing material 33 during the sterilization processing. In this case, as the material of the thermal expansion suppressing member 24, a material that does not have resistance to sterilization processing can be used.

[Third Embodiment]
A medical device electronic substrate according to a third embodiment of the present invention will be described.
FIG. 7 is a schematic longitudinal sectional view showing a configuration example of an electronic substrate for medical equipment according to the third embodiment of the present invention.

As shown in FIG. 7, the medical device electronic substrate 14 of the present embodiment is replaced with the electronic component 2 </ b> B, the thermal expansion suppressing member 4, and the sealing material 3 of the medical device electronic substrate 11 of the first embodiment. The electronic component 42B, the thermal expansion suppressing member 44, and the sealing material 43 are provided.
The medical device electronic substrate 14 can be used in place of the medical device electronic substrate 11 in the medical device in which the medical device electronic substrate 11 of the first embodiment is used.
Hereinafter, a description will be given centering on differences from the first embodiment.

  In the electronic component 42B, the mounting height of the component upper surface 42b from the substrate surface 1a is h3 higher than the mounting height h1 of the component upper surfaces 2a and 2c of the electronic components 2A and 2C. Different from the electronic component 2B in FIG.

The thermal expansion suppression member 44 is a plate member in which concave portions 44A, 44B, and 44C are formed in a part of the flat plate, whereas the thermal expansion suppression member 4 in the first embodiment is a flat plate. However, it is different from the thermal expansion suppressing member 4.
The concave portions 44A, 44B, and 44C are concave portions with respect to the lower surface 44b that is a flat surface fixed to a sealing material 43 described later. In this embodiment, since the thermal expansion suppressing member 44 has a uniform thickness, the concave portions 44A, 44B, 44C are convex portions with respect to the upper surface 44a opposite to the lower surface 44b.
The concave portions 44A, 44B, and 44C are formed in ranges that overlap the electronic components 2A, 42B, and 2C, respectively.
The bottom surfaces 44c, 44d, 44e on the lower surface 44b side of the concave portions 44A, 44B, 44C are opposed to the component upper surfaces 2a, 42b, 2c of the electronic components 2A, 42B, 2C, respectively.
The inner peripheral surfaces of the concave portions 44A, 44B, and 44C surrounding the bottom surfaces 44c, 44d, and 44e may be perpendicular to the bottom surface 44b and the bottom surfaces 44c, 44d, and 44e, or may be provided with an appropriate inclination. In the present embodiment, as an example, the inner peripheral surfaces of the concave portions 44A, 44B, and 44C have an inclination that spreads outward from the bottom surfaces 44c, 44d, and 44e toward the lower surface 44b.
Hereinafter, unless otherwise specified, the plate thickness direction and the plane direction of the flat plate portion constituting the lower surface 44b which is the main surface of the thermal expansion suppression member 44 will be described as the plate thickness direction and the plane direction of the thermal expansion suppression member 44, respectively. .

The size of the steps of the bottom surfaces 44c, 44d, 44e with respect to the bottom surface 44b is determined according to the mounting heights h1, h3, h1 of the component top surfaces 2a, 42b, 2c of the electronic components 2A, 42B, 2C from the substrate surface 1a. It has been.
By appropriately setting the step size of the bottom surface 44c, 44d, 44e with respect to the bottom surface 44b, the bottom surface 44c, 44d, 44e is sandwiched between the component top surfaces 2a, 42b, 2c of the electronic components 2A, 42B, 2C. The layer thickness of the sealing material 43 described later can be changed.
In the present embodiment, when the height of the lower surface 44b measured from the substrate surface 1a is h4, the heights of the bottom surfaces 44c, 44d, and 44e measured from the substrate surface 1a are h1 + ta, h3 + tb, and h1 + ta, respectively. Yes. However, ta ≧ tb. It is more preferable that ta is the same as h4 or a value close to h4.

The sealing material 43 is a member that is sandwiched between the circuit board 1 and the thermal expansion suppressing member 44 and seals the electronic components 2A, 2B, and 2C on the circuit board 1. The sealing material 43 is made of the same material as the sealing material 3 of the first embodiment.
The lower surface 3b of the sealing material 43 is fixed to the substrate surface 1a as in the first embodiment.
The upper surface 43a of the sealing material 43 is in close contact with and adhered to the lower surface 44b of the thermal expansion suppressing member 44 and the inner surfaces of the concave portions 44A, 44B, 44C.
In this embodiment, the layer thickness of the sealing material 43 is h4 between the substrate surface 1a and the lower surface 44b, ta between the component upper surface 2a and the bottom surface 44c, tb between the component upper surface 42b and the bottom surface 44d, It is ta between the component upper surface 2c and the bottom surface 44e.

The medical device electronic substrate 14 having such a configuration is manufactured in substantially the same manner as the medical device electronic substrate 11 of the first embodiment, with appropriate modifications.
For example, depending on the viscosity of the coating liquid and the shape of the electronic component, simply placing the thermal expansion suppressing member 44 on the coating liquid fills the concave portions 44A, 44B, and 44C with the coating liquid that becomes the sealing material 43. It may be difficult to be done. In this case, for example, the coating liquid may be applied upside down with respect to the first embodiment. For example, the thermal expansion suppression member 44 is disposed on the coating frame so that the lower surface 44b faces upward, and the coating liquid is applied to the lower surface 44b of the thermal expansion suppression member 44 and the concave portions 44A, 44B, 44C. Thereafter, the mounting surface of the circuit board 1 on which the electronic components 2A, 42B, and 2C are mounted is placed on the coating liquid. After the circuit board 1 is placed, before the curing is started, a defoaming process may be performed as necessary.

The operation of the medical device electronic substrate 14 of the present embodiment will be described.
FIG. 8 is a schematic diagram for explaining the operation when the thermal expansion suppressing member is replaced with a flat plate.

In the medical device electronic substrate 14, the action related to sealing of the sealing material 43 and the action of the thermal expansion suppressing member 44 suppressing thermal expansion in the surface direction are the sealing material 3 and heat in the first embodiment. The operation is the same as that of the expansion suppressing member 4. For this reason, according to the electronic substrate 14 for medical devices, durability with respect to the sterilization process by a heating improves like the said 1st Embodiment.
Below, it demonstrates centering around the effect | action in the plate | board thickness direction of the thermal expansion suppression member 44 different from 1st Embodiment.

The electronic substrate 15 for medical equipment shown in FIG. 8 is a configuration example in which the electronic component 2B is replaced with the electronic component 42B in the first embodiment. Here, the sealing material 3 has a relationship of h2> h3 in order to seal the electronic component 42B.
When the height h3 of the component upper surface 42b of the electronic component 42B from the substrate surface 1a is close to the layer thickness h2 of the sealing material 3, the sealing material between the substrate surface 1a and the fixing surface 4b on the outer periphery of the electronic component 42B. The difference between the layer thickness h2 of 3A and the layer thickness (h2-h3) of the sealing material 3B between the component upper surface 42b and the fixing surface 4b increases. For this reason, when the medical device electronic substrate 15 is heated, the expansion amount of the sealing material 3A is significantly larger than the expansion amount of the sealing material 3B in the layer thickness direction.
On the other hand, since the electronic component 42B has a smaller linear expansion coefficient than the sealing material 3 and is soldered onto the circuit board 1, changes in the height of the component upper surface 42b of the electronic component 42B can be ignored.
As a result, at the outer peripheral portion of the electronic component 42B, the circuit board 1 and the thermal expansion suppressing member 4 are pressed in directions away from each other in the layer thickness direction due to the thermal expansion of the sealing material 3A. However, since the thermal expansion amount of the sealing material 3B is smaller than the thermal expansion amount of the sealing material 3A, the sealing material 3B is pulled from the component upper surface 42b and the thermal expansion suppressing member 4 in the layer thickness direction.
For this reason, if the difference between the layer thickness h2 and the layer thickness (h2-h3) becomes too large, the part upper surface 42b and the sealing material 3B or the fixing surface 4b and the sealing material 3B are separated. It becomes easy.

As described above, even when the mounting height of the electronic component varies, if the layer thickness of the sealing material 3 between the component upper surface of each electronic component and the thermal expansion suppressing member 4 is increased, the heat in the layer thickness direction is increased. The relative difference in the amount of expansion is reduced.
However, when the mounting height of any of the electronic components is prominent and high, the amount of the sealing material 3 used increases, and the curing time of the sealing material 3 may increase. May increase.

In the medical device electronic substrate 14 of the present embodiment, since the thermal expansion suppressing member 44 includes the concave portions 44A, 44B, and 44C in a range covering the electronic components 2A, 42B, and 2C, the component upper surfaces 2a, 42b, and 2c The layer thickness of the sealing material 43 between the thermal expansion suppressing member 44 can be changed independently.
For example, by setting h4 = ta = tb, the pressing force acting in the layer thickness direction can be made substantially uniform due to the thermal expansion of the sealing material 43.
However, h4 and ta (tb) may be different from each other as long as the thermal stress generated by the difference in the layer thickness of the sealing material 43 in each part as described above is equal to or less than the peeling strength of the sealing material 43. The values of h4, ta, and tb can be appropriately determined by performing thermal stress analysis using numerical analysis software such as a finite element method.

For example, since an electronic component with a high mounting height is often a large electronic component, it is preferable that the electronic component is reliably pressed by the circuit board 1 side. For example, it is assumed that the electronic component 42B is an electronic component that is preferably pressed.
In this case, if tb> h4, the electronic component 42B is always pressed to the circuit board 1 side during heating, and thus the peeling of the sealing material 43 in the electronic component 42B can be more reliably prevented.
At this time, ta> h4 may be satisfied in the electronic components 2A and 2C having a lower mounting height around the electronic component 42B. However, since the resultant force of the pressing force increases as the number of electronic components increases, tb> ta or tb> ta = h4 may be set according to the mounting height.

[Second Modification to Fifth Modification]
A medical device electronic substrate according to a modification (second modification to fifth modification) of the first embodiment of the present invention will be described.
Fig.9 (a) is a typical expanded sectional view of the thermal expansion suppression member used for the electronic substrate for medical devices of the modification (2nd modification, 3rd modification) of the 1st Embodiment of this invention. . FIGS. 9B and 9C are schematic enlargements of the thermal expansion suppressing member used for the medical device electronic substrate of the modified example (fourth modified example, fifth modified example) of the first embodiment of the present invention. It is sectional drawing.

1 and 2, the medical device electronic substrates 16, 17, 18, 19 of the second to fifth modifications of the first embodiment of the present invention are all provided on the surface of the thermal expansion suppressing member. The only difference from the first embodiment is that at least one (not shown) of the concave portions and the plurality of convex portions is formed.
Hereinafter, each modified example will be described focusing on differences from the first embodiment.

The medical device electronic substrate 16 of the second modification includes a thermal expansion suppression member 54 instead of the thermal expansion suppression member 4 of the medical device electronic substrate 11 of the first embodiment.
As shown in FIG. 9A, the thermal expansion suppressing member 54 has a plurality of convex portions 54c formed on the fixing surface 4b. On the opposite side of the convex portion 54c, there may be no concave portion, but in this modified example, a concave portion 54d is formed as an example. Such convex portions 54c and concave portions 54d are formed by half-cutting processing in the case of a metal plate or by molding in the case of a ceramic plate and a resin plate.
The shape, size, arrangement pattern, number, and the like of the protrusions 54c are not limited as long as the restraining force of the sealing material 3 in the surface direction can be increased as compared with the flat fixing surface 4b.
For example, the shape, size, arrangement pattern, and number of the projections 54c in plan view are the shape, size, arrangement pattern, number of the through holes 24c of the thermal expansion suppressing member 24 of the second embodiment described above. It may be the same.
For example, the shape of the convex portion 54c may be conical, pyramidal, prismatic, hemispherical, etc., unlike the illustrated example.

  In the electronic device board 16 for medical device according to this modification, a plurality of convex portions 54 c are formed on the fixing surface 4 b of the thermal expansion suppressing member 54, so that the plurality of convex portions 54 c bite into the sealing material 3. In the thermal expansion suppressing member 54, the restraining force in the surface direction with respect to the sealing material 3 is improved as compared with the case where the convex portion 54c is not formed. For this reason, when the electronic substrate 16 for medical devices is heated, the thermal expansion suppressing member 54 can more reliably restrain the sealing material 3 fixed to the fixing surface 4b and the convex portion 54c in the surface direction. it can.

As shown in FIGS. 1 and 2, a medical device electronic substrate 17 of the third modified example is replaced with a thermal expansion suppressing member 4 instead of the thermal expansion suppressing member 4 of the medical device electronic substrate 11 of the first embodiment. 64.
As shown in FIG. 9A, the thermal expansion suppressing member 64 has a plurality of recesses 64c formed on the fixing surface 4b. On the opposite side of the concave portion 64c, there may be no convex portion, but in this modified example, a convex portion 64d is formed as an example. Such concave portions 64c and convex portions 64d are formed, for example, by half-cutting in the case of a metal plate or by molding in the case of a ceramic plate and a resin plate.
The shape, size, arrangement pattern, number, and the like of the recesses 64c are not limited as long as the restraining force of the sealing material 3 in the surface direction can be increased as compared with the flat fixing surface 4b.
For example, the shape, size, arrangement pattern, and number of the recesses 64c in plan view are the same as the shape, size, arrangement pattern, number of through holes 24c of the thermal expansion suppressing member 24 of the second embodiment. But you can.
For example, unlike the illustrated example, the shape of the recess 64c may be a conical hole shape, a pyramidal hole shape, a square hole shape, a hemispherical hole shape, or the like.

  In the medical device electronic substrate 17 of the present modification, a plurality of recesses 64c are formed on the fixing surface 4b of the thermal expansion suppressing member 64, and therefore a part of the sealing material 3 is inserted into the plurality of recesses 64c. In the thermal expansion suppressing member 64, the restraining force in the surface direction with respect to the sealing material 3 is improved as compared with the case where the concave portion 64c is not formed. For this reason, when the electronic substrate 17 for medical devices is heated, the thermal expansion suppressing member 64 can more reliably restrain the sealing material 3 fixed to the fixing surface 4b and the recess 64c in the surface direction. .

As shown in FIGS. 1 and 2, a medical device electronic board 18 of the fourth modified example is replaced with a thermal expansion suppressing member 4 instead of the thermal expansion suppressing member 4 of the medical device electronic board 11 of the first embodiment. 74.
As shown in FIG. 9B, the thermal expansion suppressing member 74 is formed with a rough fixing surface 74b instead of the flat fixing surface 4b. For example, the fixing surface 74b is formed by roughening the surface of a flat plate by roughening such as blasting or etching.
The surface roughness of the fixing surface 74b can be appropriately determined according to the restraining force required for the thermal expansion suppressing member 74. For example, the surface roughness of the fixing surface 74b may be an arithmetic average roughness Ra of 100 μm or more and 500 μm or less.

  Since the fixing surface 74b is a rough surface, the electronic substrate 18 for medical devices according to this modification has a higher fixing force with respect to the sealing material 3 than a smooth surface. As a result, the restraining force in the surface direction with respect to the sealing material 3 is improved as compared with the case where the fixing surface is a smooth surface. For this reason, when the electronic substrate 18 for medical devices is heated, the thermal expansion suppression member 74 can more reliably restrain the sealing material 3 fixed to the fixing surface 74b in the surface direction.

As shown in FIGS. 1 and 2, a medical device electronic substrate 19 according to a fifth modified example is replaced with a thermal expansion suppressing member 4 instead of the thermal expansion suppressing member 4 of the medical device electronic substrate 11 of the first embodiment. 84.
As shown in FIG. 9 ( c ), the thermal expansion suppression member 84 has a base layer 84 c formed on a surface 84 b opposite to the outer surface 4 a in the same flat plate as the thermal expansion suppression member 4.
The underlayer 84c is a layered portion that is formed by an appropriate chemical surface treatment and improves the adhesion to the sealing material 3.
As an example of the surface treatment for forming the base layer 84c, for example, a silane coupling treatment can be given.

  Since the base layer 84c is formed on the surface of the thermal expansion suppressing member 84, the medical device electronic substrate 19 of the present modification has improved adhesion to the sealing material 3 and adhesion. As a result, the restraining force in the surface direction with respect to the sealing material 3 is improved as compared with the case where the base layer 84c is not formed. For this reason, when the electronic substrate 19 for medical devices is heated, the thermal expansion suppression member 84 ensures that the sealing material 3 fixed to the thermal expansion suppression member 84 via the base layer 84c is more reliably in the surface direction. Can be restrained.

In addition, in the said 1st, 2nd embodiment and each modification, it demonstrated by the example in case the shape of a thermal expansion suppression member is flat form. However, the shape of the thermal expansion suppressing member is not limited to a flat plate shape. For example, the thermal expansion suppressing member may be a curved plate, a corrugated plate, a channel material, a member provided with a side wall on the outer periphery of a flat plate, a dish-like member, or the like.
In the thermal expansion suppressing member having a shape other than the flat plate shape, at least one of a plurality of concave portions and a plurality of convex portions may be formed on the surface. When a plurality of recesses are formed, the plurality of recesses may be formed by through holes.

  In the description of the third embodiment, the description has been given of the case where the concave portion facing each electronic component is formed when the mounting height of the electronic component is different. However, for example, when the mounting heights of the electronic components are different as in the first embodiment, a concave portion facing each electronic component may be formed.

  In the description of the third embodiment, the layer thickness of the sealing material between the electronic component and the thermal expansion suppressing member, and the gap between the electronic circuit board and the thermal expansion suppressing member in the unmounted region in the outer peripheral portion of the electronic component. In order to adjust the layer thickness to an appropriate dimension, the example in which the concave portion facing the electronic component is formed on the thermal expansion suppressing member has been described. However, for example, the shape for appropriately setting the layer thickness of the sealing material may be such that a step is formed on the thermal expansion suppressing member. For example, the thermal expansion suppressing member may include a convex portion with respect to the flat plate portion.

  In the above description of each embodiment and each modification, the thermal deformation of the medical device electronic substrate has been described with an example of expansion and contraction between normal temperature and thermal expansion due to heating during sterilization. However, the effect of suppressing the thermal deformation of the electronic substrate for medical equipment functions in the same way during expansion and contraction between the normal temperature and the low temperature. For this reason, the electronic device substrate for medical devices according to each of the embodiments and the modified examples can improve durability even when it is often stored at a low temperature such as a cold district.

  Next, Examples 1 to 3 of the electronic device substrate for medical devices corresponding to the fifth modification, the first modification, and the third embodiment of the first embodiment described above are described together with Comparative Examples 1 and 2. To do. Table 1 below shows the schematic configuration and evaluation results of each example and comparative example.

[Example 1]
Example 1 is an example of the medical device electronic substrate 19 of the fifth modified example of the first embodiment.
As the circuit board 1 of the present embodiment, a FR-4 standard glass epoxy board was used. The outer shape of the circuit board 1 was 30 mm × 50 mm, and the plate thickness was 1 mm. The linear expansion coefficient of the circuit board 1 is α1 = 13 × 10 ⁻⁶ (K ⁻¹ ).
As the electronic component of this example, a capacitor, a chip resistor, and an IC component were used. These electronic components were surface-mounted inside a 20 mm × 30 mm rectangular area near the center of the circuit board 1. The respective mounting heights were 0.5 mm, 1.0 mm, and 1.5 mm.
As shown in [Table 1], the sealing material 3 (the reference numerals are omitted in [Table 1]. The same applies to the other members), the epoxy resin coating agent 1570-2 (trade name). NAMICS Co., Ltd.) was used. The linear expansion coefficient after curing of 1570-2 is α2 = 32 × 10 ⁻⁶ (K ⁻¹ ).
The layer thickness between the circuit board 1 of the sealing material 3 and a thermal expansion suppressing member 84 described later was 4.0 mm. For this reason, the layer thickness of the sealing material 3 between the component upper surface of each electronic component and the fixing surface 4b was 3.5 mm, 3.0 mm, and 2.5 mm, respectively.
As the thermal expansion suppressing member 84, a stainless steel plate having an outer shape of 20 mm × 30 mm and a plate thickness of 1 mm was used. As a specific material of the thermal expansion suppressing member 84, SUS304 was used. The linear expansion coefficient of SUS304 is α3 = 13 × 10 ⁻⁶ (K ⁻¹ ).
The underlayer 84c of the thermal expansion suppressing member 84 was formed by a silane coupling process using a silane coupling agent KBM-403 (trade name; manufactured by Shin-Etsu Chemical Co., Ltd.).

The medical device electronic substrate 19 of this example was manufactured as follows.
On the circuit board 1 on which the electronic components are surface-mounted, a silicone resin frame having a height of 5 mm is disposed as a coating frame so as to surround an area where the electronic components are mounted. The silicone resin frame was fixed on the substrate surface 1a of the circuit board 1 with a double-sided tape.
Using a dispenser, coating agent 1570-2 was applied to the inside of the silicone resin frame after curing. The coating amount was such that the height from the substrate surface 1a after curing was 4 mm. Thereby, each electronic component was covered with the coating agent 1570-2.
Thereafter, the thermal expansion suppressing member 84 on which the base layer 84c is formed is placed on the coating agent 1570-2 in a posture facing the coating agent 1570-2 to which the base layer 84c is applied.
In this state, for example, heating was performed at 220 ° C. for 30 minutes using a heating furnace or the like. Thereby, coating agent 1570-2 was hardened and sealing material 3 was formed. After cooling, the silicone resin frame was removed, and the medical device electronic substrate 19 of Example 1 was manufactured.

[Example 2]
Example 2 is an example of the medical device electronic substrate 12 of the first modified example of the first embodiment.
The second embodiment is different from the first embodiment in that the thermal expansion suppression member 24 is used instead of the thermal expansion suppression member 84 of the first embodiment.
The thermal expansion suppressing member 24 is a punching metal material in which a circular hole having a diameter of 1 mm is penetrated in the thickness direction as a through hole 24c in SUS304 having an outer shape of 20 mm × 30 mm and a thickness of 0.5 mm. The arrangement pitch of the through holes 24c was 3 mm.

[Example 3]
Example 3 is an example in which a base layer 84c similar to that of the fifth modification is formed on the lower surface 44b of the electronic substrate 14 for medical devices and the inner surfaces of the concave portions 44A, 44B, and 44C of the third embodiment. is there.
The medical device electronic substrate 14 was formed by drawing SUS304 having a thickness of 1 mm. The bottom surfaces 44c, 44d, and 44e of the concave portions 44A, 44B, and 44C are such that when the lower surface 44b is disposed at a height of h4 = 3.0 (mm), the layer thickness of the sealing material 3 on each electronic component is It was formed to be equal to the mounting height of the electronic component.
The underlayer 84c was formed in the same manner as in Example 1 above.
Since the thermal expansion suppressing member 84 of the present embodiment has the concave portions 44A, 44B, and 44C as compared with the thermal expansion suppressing member 4 of the first embodiment, the bending rigidity is increased. Thus, the bending rigidity of the circuit board 1 is relatively lowered. Therefore, in this embodiment, the thickness of the circuit board 1 is 2 mm.

As described in the third embodiment, the electronic substrate for medical equipment of this example is mounted with a component after the coating agent 1570-2 is applied with the lower surface 44b of the thermal expansion suppressing member 44 facing upward. The circuit board 1 with the surface facing down was manufactured by being placed on the coating agent 1570-2.
The mounting position of the thermal expansion suppressing member 44 was set to a position where the layer thickness of the cured sealing material 43 between the lower surface 44b and the substrate surface 1a was h4 = 3.0 (mm). Thereby, the layer thickness of the sealing material 43 after hardening between the component upper surface of each electronic component and the bottom surface of each concave-shaped part was a layer thickness equal to the mounting height of each electronic component.

[Comparative Examples 1 and 2]
As shown in [Table 1], the electronic substrate for medical devices of Comparative Example 1 was configured to cover each electronic component on the circuit board 1 with a sealing material 3 having the same layer thickness as in Example 1 above. Comparative Example 1 has the same configuration as that in which the thermal expansion suppressing member 4 of Example 1 is deleted.
In Comparative Example 2, the material of the sealing material 3 in the above Comparative Example 1 was changed to Dow Corning (registered trademark) SE 9186 (trade name; manufactured by Toray Dow Corning Co., Ltd.), which is a silicone resin-based sealing material. This is different from Comparative Example 1. The linear expansion coefficient of the cured product of SE 9186 is α2 = 250 × 10 ⁻⁶ (K ⁻¹ ).

[Evaluation methods]
The durability against autoclave sterilization was evaluated using the medical device electronic substrates of Examples 1 to 3 and Comparative Examples 1 and 2 as test samples.
In the autoclave sterilization, the treatment of exposing the test sample to a steam gas at 130 ° C. and 2 atm for 30 minutes was taken as one example (one time). The test samples of each example and each comparative example were subjected to autoclave sterilization treatment of 10 cases, 100 cases, and 300 cases, each consisting of 5 samples. During each example of autoclave sterilization, the test sample was left in an environment of 25 ° C. and 60% RH for 60 minutes.
After all of the autoclave sterilization treatments were completed, an energization test of each sample was performed. If there is no abnormality in the electrical characteristics of all five test samples as a result of the current test, it is evaluated as good (indicated in Table 1 as “good”) and one or more test samples. When the electrical characteristics of the film became defective, it was evaluated as defective (in Table 1, it was described as x (no good)). [Table 1] shows the test results as (n / N) where n is the number of good products (n = 0,..., 5) and N is the evaluation number (= 5).

[Evaluation results]
As shown in [Table 1], in all of Examples 1 to 3, even when the autoclave sterilization treatment of 10 cases, 100 cases, and 300 cases is performed, abnormality may appear in the electrical characteristics of the total number of test samples. There was no.
On the other hand, in the test sample of Comparative Example 1, only one good product was present in 10 cases, and in 100 cases and 300 cases, the total number of electrical characteristics was poor.
The sample samples of Comparative Example 2 were evaluated as good in 10 cases, but in 100 cases and 300 cases, 2 and 4 electrical characteristics were evaluated as poor, respectively.
The failure in Comparative Examples 1 and 2 was a failure in electrical characteristics caused by a crack in the solder mounting portion of the electronic component. These defects are thought to have been caused by repeated thermal expansion by the sterilization cycle.
Moreover, the defect of the comparative example 2 was a defect by having caused the conduction defect by the corrosion on the wiring on a glass epoxy board | substrate. This defect is considered to have occurred because water vapor permeated through the sealing resin and entered the sealing resin.
In contrast, in all of Examples 1 to 3, the thermal expansion suppressing member reduced the thermal stress due to the thermal expansion of the sealing material or the stress load due to repeated warping deformation of the circuit board. It is thought that durability was improved. Moreover, it is considered that water vapor permeation could be effectively prevented because a sealing resin having low water vapor permeability but high elastic modulus can be employed.

As mentioned above, although each preferable embodiment and each modification of this invention were described with each Example, this invention is not limited to each of these embodiment, each modification, and each Example. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention.
Further, the present invention is not limited by the above description, and is limited only by the appended claims.

1 Circuit board (electronic circuit board)
1a Substrate surface 2a, 2b, 2c, 42b Component upper surface 2A, 2B, 2C, 42B Electronic component 3, 3A, 3B, 23, 33, 43 Sealant 3a, 23a, 33a, 43a Upper surface 3b Lower surface 4, 24, 44 , 54, 64, 74, 84 Thermal expansion suppressing member 4b, 74b Adhering surface 11, 12, 13, 14, 15, 16, 17, 18, 19 Medical device electronic board 24c Through hole 44A, 44B, 44C Concave portion 44b Lower surface 44c, 44d, 44e Bottom surface 54c Convex part 64c Concave part 84b Surface 84c Underlayer

Claims (4)

An electronic circuit board having a first linear expansion coefficient;
A plurality of electronic components mounted on the electronic circuit board;
A sealing material that has a second linear expansion coefficient larger than the first linear expansion coefficient and is fixed to the electronic circuit board and the plurality of electronic components in a state of covering the plurality of electronic components;
The sealing material having a third linear expansion coefficient smaller than the second linear expansion coefficient and covering the plurality of electronic components with the sealing material sandwiched between the electronic circuit board and the electronic component. A thermal expansion suppressing member fixed to the
With
The thermal expansion suppressing member has at least one of a plurality of concave portions and a plurality of convex portions on a surface fixed to the sealing material.
Electronic board for medical equipment. An electronic circuit board having a first linear expansion coefficient;
A plurality of electronic components mounted on the electronic circuit board;
A sealing material that has a second linear expansion coefficient larger than the first linear expansion coefficient and is fixed to the electronic circuit board and the plurality of electronic components in a state of covering the plurality of electronic components;
The sealing material having a third linear expansion coefficient smaller than the second linear expansion coefficient and covering the plurality of electronic components with the sealing material sandwiched between the electronic circuit board and the electronic component. A thermal expansion suppressing member fixed to the
With
The thermal expansion suppression member has a plurality of through-holes that open to the surface that adheres to the sealing material .
Medical療機dexterity electronic substrate. An electronic circuit board having a first linear expansion coefficient;
A plurality of electronic components mounted on the electronic circuit board;
A sealing material that has a second linear expansion coefficient larger than the first linear expansion coefficient and is fixed to the electronic circuit board and the plurality of electronic components in a state of covering the plurality of electronic components;
The sealing material having a third linear expansion coefficient smaller than the second linear expansion coefficient and covering the plurality of electronic components with the sealing material sandwiched between the electronic circuit board and the electronic component. A thermal expansion suppressing member fixed to the
With
The thermal expansion suppressing member has at least a step formed on the surface that is fixed to the sealing material,
The layer thickness of the sealing material between at least one electronic component of the plurality of electronic components and the thermal expansion suppressing member is such that the electronic circuit board in an unmounted region in the outer peripheral portion of the at least one electronic component More than the layer thickness of the sealing material between the thermal expansion suppression member ,
Medical療機dexterity electronic substrate. The thermal expansion suppressing member is
On the surface that adheres to the sealing material, it has a base layer that improves adhesion with the sealing material,
The electronic substrate for medical devices according to any one of claims 1 to 3 .

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