JP2002141676A - Electric equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide electric equipment that can prevent the adverse influence of a resin through the equipment uses the resin between the lower surface of a circuit board and internal side face of a container to efficiently radiate the heat generated from heat generating parts. SOLUTION: The circuit board 1 mounted with electronic parts 4 is housed in a container 2. The electronic parts 4 are fixed by soldering on the lower surface of the board 1. Of the electronic parts 4, those generating large quantities of heat are surface-mounted on the lower surface of the board 1. The resin 3 is only packed in the space between the lower surface of the board 1 and the internal side face of the container 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric apparatus in which a container for accommodating a circuit board is filled with resin so as to promote heat radiation of electronic components.

[0002]

2. Description of the Related Art In general, in an electric device having a heat-generating component such as a discharge lamp lighting device, a high-rated electronic component is used in order to suppress the amount of heat generation and prevent thermal destruction. As a result, the board area of the circuit board on which the electronic components are mounted is increased, and the size of the electric device is increased. Also,
In general, a heat radiating plate is attached to the heat generating component to promote heat radiation, which also causes an increase in the size of the electric device.

In order to reduce the size of electrical equipment while taking measures to dissipate heat from heat-generating components, Japanese Patent Application Laid-Open No. 1-2208 discloses a technique in which a circuit board on which electronic components are mounted is covered with a resin for heat dissipation.
No. 89, for example. According to the technique described in this publication, as shown in FIG. 9, a container 2 in which a circuit board 1 on which electronic components 4 are mounted is filled with a resin 3, and the circuit board 1 is The resin 3 is filled to such an extent that the resin 3 is embedded.

[0004]

By the way, if the circuit board 1 is embedded in the resin 3 as described above,
When the resin 3 is filled, the resin 3 wraps between the circuit board 1 and the electronic component 4, and the expansion and contraction of the resin 3 due to the temperature change causes the force between the circuit board 1 and the electronic component 4 as shown in FIG. F will work. Since this force F is transmitted to the solder 6 in a direction orthogonal to the surface of the circuit board 1 through the leads 5 of the electronic component 4, there is a possibility that a shear force acts on the solder 6 and the solder 6 peels off. . For example, when the resin 3 shrinks at low temperature, the electronic component 4
Is generated in such a direction as to bring the solder 6 close to the circuit board 1.
May generate a shear stress, and cracks may occur in the solder 6.

In the case of an electronic component 4 having a gap around it, such as a variable resistor or a terminal, when the resin 3 is filled in the container 2, the resin 3 before curing enters the electronic component 4 from the gap due to a capillary phenomenon. Infiltration may occur and poor contact may occur. For example, in a terminal 10 in which a metal component 12 serving as a contact is provided in a housing 11 of a synthetic resin molded product as shown in FIG. 11, the filling resin 3 is filled through a gap between the housing 11 and the metal component 12. It may invade (the infiltration site is indicated by X). In order to avoid such a problem, it is considered that an electronic component 4 such as a variable resistor or a terminal is floated from the circuit board 1, but it takes time and effort to mount the electronic component 4.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to fill a resin for efficiently dissipating heat from a heat-generating component while preventing the above-mentioned adverse effects of the resin from being caused. To provide equipment.

[0007]

According to a first aspect of the present invention, there is provided an electric apparatus in which a resin for radiating heat is filled in a container in which a circuit board on which electronic components are mounted is housed. The electronic component having a large calorific value is surface-mounted on the one surface and the resin is filled only between the one surface of the circuit board and the inner surface of the container.

[0008] The invention of claim 2 is characterized in that, in the invention of claim 1, the resin is a urethane resin.

According to a third aspect of the present invention, in the second aspect of the present invention, the hardness of the resin in a type A durometer hardness test specified in JIS K-6253 does not exceed 88 at the lower limit temperature of the operating temperature range. It is characterized by.

According to a fourth aspect of the present invention, in the second or third aspect of the invention, a portion between the one surface of the circuit board and the inner surface of the container and not affecting a heat radiation path of the electronic component is provided. A hollow portion not filled with the resin is provided.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, a through hole communicating with the cavity is formed in the circuit board.

A sixth aspect of the present invention is characterized in that, in the first aspect of the present invention, the resin is a silicone resin.

According to a seventh aspect of the present invention, in the sixth aspect of the invention, the product of the hardness and the coefficient of linear thermal expansion of the silicone resin in a type A durometer hardness test specified in JIS K-6253 exceeds 0.0113. It is characterized by not having.

The invention of claim 8 is characterized in that, in the invention of claims 1 to 7, the resin exhibits thixotropy and the structural viscosity ratio does not fall below 1.5.

According to a ninth aspect of the present invention, in the first to eighth aspects, the viscosity of the resin in a sol state is 10%.
It does not fall below 0 Pa · s.

According to a tenth aspect of the present invention, in the first to ninth aspects, a lighting circuit for lighting a discharge lamp is mounted on the circuit board.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) As shown in FIG. 1, in an electric apparatus according to the present embodiment, an electronic component 4 is mounted on a circuit board 1 composed of a printed circuit board. The circuit board 2 is a synthetic resin molded product which is housed in a container 2 having one side (the upper surface in FIG. 1) open and in which a part of the container 2 is filled with a resin 3 for heat radiation.
In this embodiment, the resin 3 is filled only between the surface on which the electronic component 4 is fixed by soldering and the inner surface of the container 2. In this embodiment, a discharge lamp lighting circuit for lighting a discharge lamp is mounted on the circuit board 1. This type of circuit includes an electronic component 4 that generates a large amount of heat, such as a switching element. A urethane resin is used for the resin 3. By adopting this configuration,
It is possible to prevent cracks from occurring in the solder due to expansion and contraction of the resin 3 that has flowed between the circuit board 1 and the electronic component 4. In addition, the container 2 may be made of metal in order to increase heat radiation efficiency.

By the way, as shown in FIG. 1, in order to fill the resin 3 only between the circuit board 1 and the inner peripheral surface of the container 2, the following procedure is employed in this embodiment. First, FIG.
As shown in FIG. 2A, the resin 3 was raised on the bottom surface of the container 2 having an open upper surface, with the central portion being higher than the peripheral portion, and then the electronic component 4 was mounted as shown in FIG. 2B. The resin 3 is spread on the circuit board 1. Here, a single-sided board having a conductive pattern on one side is used as the circuit board 1,
The electronic component 4 is mainly arranged on one surface side of the circuit board 1,
The leads of the electronic component 4 are drawn out to the other surface side and fixed by soldering. Further, some of the electronic components (particularly, electronic components having a large heat value) 4 are surface-mounted on the other surface side of the circuit board 1. Using such a circuit board 1, the surface on which the electronic component 4 is fixed by soldering is brought into contact with the resin 3 to spread the resin 3. In this way, as shown in FIG. 2C, the resin 3 is substantially uniformly spread and filled between the inner peripheral surface of the container 2 and the circuit board 1. The resin 3 can be brought into close contact with the electronic component 4 mounted on the circuit board 1 in the above-described procedure, and heat can be radiated through the resin 3.

In order to raise the center of the resin as shown in FIG. 2A, the present embodiment uses the resin 3 exhibiting thixotropic. The thixotropic means a property or a phenomenon in which, when force is continuously or repeatedly applied, the viscosity decreases and the fluidity increases from a gel to a sol, and when the force is removed, the sol returns to a gel. The properties of thixotropic are expressed using the structural viscosity ratio. In the present embodiment, the resin 3 whose structural viscosity ratio does not fall below 1.5 is selected. By using such a resin 3, the process shown in FIG. 2 can be realized. Here, the structural viscosity ratio means the ratio of the viscosity measured at 2 rms by a rotational viscometer to the viscosity measured at 20 rms.

Incidentally, the structural viscosity ratio of the resin is 1.0 to
When the height of the resin was increased in the range of 3.0 and 30 g of the resin heated to 50 ° C. was dropped on a flat plate, and the height of the resin was confirmed, the results shown in Table 1 were obtained.

[0021]

[Table 1]

The selection of the structural viscosity ratio depends on the size of the container 2 and the distance between the inner peripheral surface (bottom surface) of the container 2 and the circuit board 1.
In the present embodiment, the distance between the bottom surface of the container 2 and the circuit board 1 is 4
If the height of the resin 3 is 5 mm or more, it is determined that the resin 3 can be used. This condition is satisfied if the structural viscosity ratio does not fall below 1.5.

With the above configuration, the resin 3 does not enter between the electronic component 4 disposed on the upper surface of the circuit board 1 and the circuit board 1, and the electronic component 4 is mounted by expansion and contraction of the resin 3. Cracks can be prevented from occurring in the solder that is being used.

On the other hand, in order to prevent the resin 3 from entering through gaps formed in the electronic component 4 such as a variable resistor and a terminal, in the present embodiment, a resin 3 whose viscosity does not fall below 100 Pa · s is selected. are doing.

Incidentally, after the circuit board 1 on which the terminals are actually mounted is placed in the container 2 and filled with the resin 3, the terminals are cut so that the cross section of the terminals can be seen, and the presence or absence of penetration of the resin 3 is checked. Was confirmed, the results shown in Table 2 were obtained. Here, the viscosity of the resin 3 is 10 to 500 Pa · s.
The range was used. In Table 2, ○ means that no intrusion of the resin 3 was observed, and X means that there was intrusion of the resin 3.

[0026]

[Table 2]

As is clear from Table 2, the viscosity is 100 P
When resin 3 not less than a · s was used, it was possible to prevent the resin from penetrating into terminals as electronic components. this is,
It is considered that the resin 3 having a large viscosity has a strong bonding force between molecules and a low fluidity. Now, as a simple model, consider a case where the wall 13 is arranged so as to be orthogonal to the liquid surface of the resin 3 as shown in FIG. In the conventionally used resin 3 having a small viscosity, a force f1 acts upward on the wall 13 as shown in FIG. 3A, so that the contact portion between the resin 3 and the wall 13 is higher than the liquid level S of the resin 3. On the contrary, in the case of the resin 3 having a large viscosity, a force f2 acts downward on the wall 13 as shown in FIG. 3B, and the contact portion between the resin 3 and the wall 13 is lower than the liquid level S of the resin 3. Become. That is, by using the resin 3 having a relatively high viscosity as in the present embodiment, the electronic component 4
It is possible to prevent infiltration into the air.

As described above, if a resin having a viscosity exceeding 100 Pa · s and a structural viscosity ratio exceeding 1.5 is selected as the resin 3 to be filled in the container 2, the resin 3 can be applied to the electronic component 4. Infiltration is prevented, and expansion and
Cracking of the solder due to shrinkage is prevented.
By the way, since the resin 3 is intended to dissipate heat, it is necessary to use a material having a relatively high thermal conductivity as the resin 3. Therefore, filler (filler) is used for resin 3.
Is added to increase the thermal conductivity of the resin 3, but the addition of the filler increases the hardness of the resin 3. Here, at a low temperature, the circuit board 1 shrinks and the resin 3 also shrinks. Since the shrinkage of the resin 3 is generally larger than that of the circuit board 1, the shrinkage of the resin 3 adhered to the circuit board 1 causes the circuit board to shrink. 1, an external force acts in the direction along the surface, and a stress is generated along the surface of the circuit board 1 on which the electronic component 4 is fixed by soldering. A crack called a ring crack occurs in the solder). In particular, it is known that when the hardness of the resin 3 increases, the difference in the shrinkage ratio with the circuit board 1 increases, and the possibility that the solder is sheared due to expansion and contraction of the resin 3 increases.

As is apparent from the above description, it can be said that the hardness of the resin 3 should be limited in order to prevent the shearing of the solder caused by adding the filler to the resin 3. Therefore, in this embodiment, as a method of evaluating the hardness of the resin 3,
A type A durometer hardness test specified in JIS K-6253 was applied, and an upper limit value was set for the hardness. That is, based on the results of the evaluation tests described below, the lower limit temperature (−
(40 ° C.) so that the hardness does not exceed 88.

As an evaluation test, the hardness of the resin 3 was set to 60 to 10
The temperature was changed in the range of 5 and the test temperature was set to −40 ° C. and 80 ° C., and the temperature change test was performed for 30 minutes each and 500 cycles. As a result, as shown in Table 3, the hardness was 1
In the case of No. 05, cracks occurred in the solder, but the result was obtained that no crack occurred in the solder in the range where the hardness did not exceed 88. Therefore, in the present embodiment, a resin to which a filler is added is used so that the hardness does not exceed 88, and thereby, the shearing of the solder due to the expansion and contraction of the resin 3 can be prevented. In Table 3, “with cracks” means occurrence of ring cracks. Here, the resin 3 was filled only between the lower surface of the circuit board 1 (the surface on which the solder was fixed) and the inner peripheral surface of the container 2, and the elastic modulus and hardness were measured at −40 ° C. “JIS A” in Table 3 means hardness measurement by a type A durometer hardness test specified in JIS K-6253.

[0031]

[Table 3]

The reason why cracking of solder due to temperature change can be prevented by limiting the hardness will be described. Now, suppose that the resin length changes from l1 to l2 (<l1) when the temperature changes from T1 to T2 (<T1. If this deformation is expressed in relation to the stress of the resin, it is considered as follows. In other words, in general, the deformation of a resin is assumed to be in accordance with Hooke's law because the object generally satisfies Hooke's law in a range where the deformation is sufficiently small, and in this case, the elastic modulus, which is a constant determined for each substance, is
Since the proportional relationship between the amount of expansion and contraction relative to the original length and the stress per unit cross-sectional area generated in the substance is expressed, the elastic modulus = (stress per unit cross-sectional area) / (the amount of expansion and contraction relative to the original length) Become. That is, if the elastic modulus at the temperature T2 is represented by E and the thermal stress of the cross-sectional area A is represented by F / A, the following equation is established. F / A = E (Δl / 11) (1) On the other hand, if the deformation of the resin is considered as the deformation due to the temperature change and the coefficient of linear thermal expansion is α, the following equation is established. Δl / 11 = α (T1−T2) = α · ΔT (2) By substituting equation (2) into equation (1), the following equation is obtained. F / A = E · α · ΔT (3) In short, the stress per unit cross-sectional area is proportional to the temperature difference ΔT. Considering a range of −40 to 80 ° C. as a test condition relating to a temperature change for confirming a state of the solder, in the case of urethane resin, as shown in FIG. On the other hand, as shown in FIG. 5, the elastic modulus E increases as the temperature decreases, and the elastic modulus E becomes maximum at the lower limit of −40 ° C. in the temperature range of the test conditions. Therefore, according to the equation (3), the maximum value of the thermal stress of the resin 3 is determined by the elastic modulus E at −40 ° C. That is, it is possible to prevent the occurrence of cracks in the solder by considering the elastic modulus E of the resin 3. Since the elastic modulus E of the resin indicates the difficulty of deformation, the elastic modulus E can be regarded as the hardness of the resin 3. Actually, as shown in FIG. 6, the elastic modulus and the hardness show the same temperature characteristic. Therefore, in the present embodiment, the hardness measured as a general physical property of the resin is used as the condition of the resin 3 instead of the elastic modulus, and the occurrence of cracks in the solder is prevented by limiting the hardness. It is.

As an example, the resin 3 has a structural viscosity ratio of 2.0
When the hardness at −40 ° C. was set to 80, the condition of the resin 3 of the present embodiment was satisfied, and the crack of the solder due to the temperature change was prevented.

(Second Embodiment) FIG. 7 shows the configuration of the present embodiment. In the present embodiment, a cavity 7 not filled with the resin 3 is provided between the lower surface of the circuit board 1 and the inner peripheral surface of the container 2. The urethane resin as the resin 3 generates a urethane bond by a chemical reaction between the polyisocyanate and the polyol, and is cured. Here, polyisocyanate is a highly reactive material, and reacts with water to produce carbon dioxide (C
O ₂ ). On the other hand, since the circuit board 1 contains a small amount of water, the water contained in the circuit board 1 generates carbon dioxide gas on the contact surface between the circuit board 1 and the resin 3 to form bubbles. Circuit board 1 and electronic components 4
And the resin 3 do not adhere to each other, so that the heat radiation property is reduced. Therefore, the cavity 7 is provided at a location where the influence on the heat radiation path from the electronic component 4 is small, and the generated carbon dioxide gas is released to the cavity 7 to reduce the degree of adhesion between the electronic component 4 and the resin 3. It prevents the decline. Here, as shown in FIG. 8, a through hole 8 is formed at a position corresponding to the cavity 7 in the circuit board 1, and the upper surface side of the circuit board 1 and the cavity 7 communicate with each other through the through hole 8. ,
The carbon dioxide gas generated by the reaction between the polyisocyanate and water is released to the outside air through the through-holes 8 and the cavity 7 is formed.
Can prevent stress on the circuit board 1 due to expansion and contraction of the air inside the circuit board, and as a result, stress on the solder can be reduced. The situation is indicated by arrows). In FIG. 8, the inclination direction of the boundary between the resin 3 and the cavity 7 is changed from that of FIG.
As described in the first embodiment, since the resin 3 is introduced into the container 2 with the central portion of the resin 3 raised, the shape shown in FIG. 8 is easier to realize than the shape shown in FIG. .

(Third Embodiment) In the first embodiment, an example in which a urethane resin is used as the resin 3 has been described, but in this embodiment, a silicon resin is used as the resin 3. Since the basic configuration is the same as that of the first embodiment, the following mainly describes differences from the first embodiment. As in the case of the first embodiment, a resin 3 that exhibits thixotropy, has a structural viscosity ratio of less than 1.5 and a viscosity of not less than 100 Pa · s is used. However, with regard to the hardness of the resin 3, in the first embodiment, the characteristics of the resin 3 are defined only by the hardness according to the type A durometer hardness test specified in JIS K-6253. And the coefficient of linear thermal expansion are set so as not to exceed 0.0113 at the lower limit temperature (−40 ° C.) of the operating temperature range.

That is, as an evaluation test, the product of the hardness and the coefficient of linear thermal expansion was changed in the range of 0.0080 to 0.0130, the test temperature was -40 and 80 ° C., and the standing time was 3 times.
A temperature change test was performed for 500 cycles at 0 minutes. As a result, the same results as in Table 3 were obtained. The above product is 0.01
In the case of No. 30, cracks occurred in the solder.
In the range not exceeding 13, the result that no crack was generated in the solder was obtained. Therefore, in the present embodiment, a resin whose product of the hardness and the coefficient of linear thermal expansion does not exceed 0.0113 is used, whereby the shearing of the solder due to the expansion and contraction of the resin 3 can be prevented.

In this embodiment, as described in the first embodiment, the equation (3) is satisfied. However, in the case of urethane resin, the coefficient of linear thermal expansion α is within the temperature range of the test condition (that is, the operating temperature range). In silicon resin, the elastic modulus is not only affected by the ambient temperature, but also the coefficient of linear thermal expansion α decreases with the increase of the filler. It is necessary to consider both. That is, according to equation (3), the maximum value of the thermal stress of the resin 3 is determined by the product of the elastic modulus E and the linear thermal expansion coefficient α.
By considering the product of the above, it is possible to solve the problem that cracks occur in the solder. Other configurations and functions are the same as those of the first embodiment.

In this embodiment, when the product of the hardness of the resin 3 and the coefficient of linear thermal expansion is set to 0.01, the thermal stress of the resin 3 can be suppressed, and the distance between the circuit board 1 and the leads of the electronic component 4 can be reduced. , And the occurrence of cracks in the solder due to shearing force can be prevented.

[0039]

According to the first aspect of the present invention, there is provided an electric device in which a resin for heat dissipation is filled in a container in which a circuit board on which an electronic component is mounted is housed, wherein the electronic component is fixed by soldering on one surface of the circuit board. And an electronic component having a large calorific value is surface-mounted on the one surface, and a resin is filled only between the one surface of the circuit board and the inner surface of the container. Since the resin for heat dissipation is filled between the surface on which the components are mounted and the inner peripheral surface of the container housing the circuit board, heat from the electronic components can be radiated through the resin, and Not only can the temperature rise be suppressed, but also by mounting electronic components with gaps such as variable resistors and terminals on the surface of the circuit board that is not in contact with the resin, these electronic components Tree There can be prevented from entering. As a result, troublesome operations such as placing these electronic components off the circuit board become unnecessary, which facilitates production, reduces production cost, and reduces the height of the container.

According to a second aspect of the present invention, in the first aspect, the resin is a urethane resin, and a relatively inexpensive resin can be used for heat radiation.

According to a third aspect of the present invention, in the second aspect of the invention, the hardness of the resin in a type A durometer hardness test specified in JIS K-6253 does not exceed 88 at the lower limit temperature of the operating temperature range. The stress generated on the circuit board due to expansion and contraction of the resin due to the change in ambient temperature can be made relatively small, and as a result, cracks occur in the solder fixing the electronic components to the circuit board. Can be prevented.

According to a fourth aspect of the present invention, in the second or third aspect, a portion between the one surface of the circuit board and the inner surface of the container and not affecting a heat radiation path of the electronic component is provided. It is provided with a hollow portion not filled with the resin, the carbon dioxide gas generated by the reaction of moisture with the substance that generates the urethane resin can be released to the hollow portion, and the resin and the electronic component or circuit are generated by the generation of the carbon dioxide gas. A decrease in the degree of adhesion to the substrate can be prevented. As a result, it becomes possible to efficiently dissipate heat by bringing the resin into close contact with the electronic component.

According to a fifth aspect of the present invention, in the fourth aspect of the present invention, a through hole communicating with the cavity is formed in the circuit board, and the carbon dioxide gas entering the cavity is exposed to the outside air through the through hole. When the air inside the cavity expands and contracts due to the ambient temperature, no pressure acts on the circuit board, and as a result, mechanical stress acts on the solder for mounting the electronic components. Can be prevented.

According to a sixth aspect of the present invention, in the first aspect of the invention, the resin is a silicone resin, and a relatively inexpensive resin can be used for heat radiation.

According to a seventh aspect of the present invention, in the sixth aspect of the invention, the product of the hardness and the coefficient of linear thermal expansion of the silicone resin in the type A durometer hardness test specified in JIS K-6253 exceeds 0.0113. The stress that occurs on the circuit board due to the expansion and contraction of the resin due to changes in the ambient temperature can be made relatively small, and as a result, cracks occur in the solder that fixes the electronic components to the circuit board. Can be prevented.

The invention of claim 8 is characterized in that, in the invention of claims 1 to 7, the resin exhibits thixotropy and the structural viscosity ratio does not fall below 1.5. It is possible to introduce the resin with the center part raised from the peripheral part, and then fill the container with the resin while pressing the resin on the circuit board, so that the resin and the circuit board and the electronic components surface-mounted on the circuit board can be separated. The electronic components can be radiated efficiently by the resin.

According to a ninth aspect of the present invention, in the first to eighth aspects, the viscosity of the resin in a sol state is 10%.
It does not fall below 0 Pa · s, and even with electronic components having gaps such as variable resistors and terminals, resin hardly penetrates into the inside, and the possibility of causing poor contact or malfunction is reduced, and as a result, The yield is improved.

According to a tenth aspect of the present invention, in the first to ninth aspects of the present invention, a lighting circuit for lighting a discharge lamp is mounted on the circuit board. Since heat can be efficiently radiated from the parts by using the resin, it is possible to reduce the size of the discharge lamp lighting device, and furthermore, by adopting the configuration of the invention described in each of the above claims, the effects corresponding to these claims can be obtained. Will be played.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a process chart showing a manufacturing process of the same.

FIG. 3 is a diagram illustrating the principle of the above.

FIG. 4 is a diagram illustrating the principle of the above.

FIG. 5 is a diagram illustrating the principle of the above.

FIG. 6 is a diagram illustrating the principle of the above.

FIG. 7 is a sectional view showing a second embodiment of the present invention.

FIG. 8 is an enlarged sectional view of a main part of the above.

FIG. 9 is an enlarged sectional view showing a conventional example.

FIG. 10 is a cross-sectional view showing the above problem.

FIG. 11 is a cross-sectional view showing the above problem.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Circuit board 2 Container 3 Resin 4 Electronic component 5 Lead 6 Solder 7 Hollow part 8 Through-hole

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kazuhiro Nishimoto 1048 Kazumasa Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. 72) Inventor Norio Kanai 1048 Kadoma Kadoma, Osaka Prefecture Inside Matsushita Electric Works, Ltd. (72) Inventor Shunichi Hongo 404-1, Nishinobumatsu, Himeji City, Hyogo Prefecture Ikeda Electric Co., Ltd. 404-1, Nishinobumatsu, Himeji-shi, Ikeda Electric Co., Ltd. (72) Inventor Kazushige Ito 404-1, Nishinobumatsu, Himeji-shi, Hyogo Ikeda Electric Co., Ltd. F-term (reference) 3K014 LB02 4E360 CA02 EA24 ED22 EE02 GA12 GA24 GA52 GA53 GB51 GB97 GC08 GC11 5E322 AA11 AB09 EA11 FA05

Claims (10)

[Claims] 1. An electric device in which a resin for heat dissipation is filled in a container in which a circuit board on which an electronic component is mounted is housed, wherein the electronic component is fixed on one surface of the circuit board by soldering and generates a large amount of heat. An electronic device, wherein an electronic component is surface-mounted on the one surface, and a resin is filled only between the one surface of the circuit board and the inner surface of the container. 2. The electric device according to claim 1, wherein the resin is a urethane resin. 3. The resin according to JIS K-625.
3. The electric apparatus according to claim 2, wherein the hardness according to the type A durometer hardness test specified in 3 does not exceed 88 at the lower limit temperature of the operating temperature range. 4. A cavity that is not filled with the resin is provided between the one surface of the circuit board and the inner surface of the container and does not affect a heat radiation path of the electronic component. The electric device according to claim 2 or 3. 5. The electric device according to claim 4, wherein a through-hole communicating with the cavity is formed in the circuit board. 6. The electric device according to claim 1, wherein the resin is a silicone resin. 7. The resin according to JIS K-625.
7. The electrical device according to claim 6, wherein the product of the hardness and the coefficient of linear thermal expansion in the type A durometer hardness test specified in 3 does not exceed 0.0113. 8. The electric device according to claim 1, wherein the resin exhibits thixotropy and a structural viscosity ratio does not fall below 1.5. 9. The resin in a sol state having a viscosity of 100 P
The electrical device according to any one of claims 1 to 8, wherein the value does not fall below a · s. 10. The electric device according to claim 1, wherein a lighting circuit for lighting a discharge lamp is mounted on the circuit board.