JP5681076B2 - LED bulb and LED bulb case - Google Patents

Description

  The present invention relates to an LED bulb using an LED (Light Emitting Diode) as a light emitting element and an LED bulb case.

  In recent years, LED bulbs have been developed that use LEDs having a long life and high energy efficiency as compared with incandescent bulbs. In the development of the LED bulb, improvement of heat dissipation during LED emission is an important issue, and a technique for this has been proposed. For example, in an LED bulb as disclosed in Patent Document 1, the heat generated in the LED is from the LED to the LED substrate, from the LED substrate to the mounting member, and from the mounting member to the housing Heat is quickly transferred to the member and radiated from the housing member. A plurality of LEDs are usually arranged on the LED substrate, but the above-mentioned mounting member and the housing member are made of a heat conductive metal (for example, aluminum) so as to suppress the temperature rise of the LED. Yes.

Japanese Patent No. 4659131 WO 03/064150 A1 WO 2004/041532 A1

  As in the example described above, various techniques have been proposed for the heat dissipation path of the heat generated in the LED. On the other hand, the heat generated by the LED stays around the lighting circuit that controls the lighting of the LED, or the heat generated by the lighting circuit itself inside the housing stays around the lighting circuit, so that the lighting circuit There is a risk of adversely affecting the electronic components forming the. Therefore, it is necessary to increase the heat radiation efficiency around the lighting circuit. Considering that the distance between the LED and the lighting circuit will be shortened and the density of electronic components will be improved as the size of the LED is reduced in the future, improving the heat dissipation performance around the lighting circuit is an important problem.

  The present invention has been made to solve the above-described problems, and achieves the following object. An object of the present invention is to provide an LED bulb and a case for an LED bulb that suppress heat retention around a lighting circuit.

  The present invention takes the following means in order to achieve the object. The reference numerals used in the description of the best mode for carrying out the invention and the drawings to be described later are appended in parentheses for reference, but the constituent elements of the present invention are not limited to the appended description.

The LED bulb of the present invention 1
A substrate on which an LED is mounted;
A lighting circuit that receives power through the base and lights the LED;
A circuit cover that houses the lighting circuit;
An aluminum case that dissipates heat when the LED is lit;
An LED bulb comprising:
The circuit cover is an injection-molded article composed of a resin composition containing at least one selected from polybutylene terephthalate, polyphenylene sulfide, and polyamide resin,
Asperities are formed on the surface of the case, and the circuit cover and the case are integrated by the resin composition constituting the injection molded product entering the irregularities.
An insulating part that is configured by the resin composition and insulates the base and the case, a heat radiating part that is configured by the resin composition and is exposed to the outside of the case, and is configured by the resin composition and the base is fixed. The base fixing part is formed integrally .

The LED bulb of the present invention 2 is
A substrate on which an LED is mounted;
A lighting circuit that receives power through the base and lights the LED;
An aluminum circuit cover that houses the lighting circuit;
An aluminum case that dissipates heat when the LED is lit;
An LED bulb comprising:
It is composed of a resin composition containing at least one selected from polybutylene terephthalate, polyphenylene sulfide, and polyamide resin, and has an injection molded product that comes into contact with the circuit cover and the case,
Concavities and convexities are formed on the circuit cover surface and the case surface, and the resin composition constituting the injection-molded product penetrates into the concavities and convexities on both the circuit cover surface and the case surface. The circuit cover and the case are integrated,
An insulating part that is configured by the resin composition and insulates the base and the case, a heat radiating part that is configured by the resin composition and is exposed to the outside of the case, and is configured by the resin composition and the base is fixed. The base fixing part is formed integrally .

The LED bulb of the present invention 3 is the LED bulb of the present invention 1 or 2,
The insulating part and the heat radiating part are the same part.

The LED bulb case of the present invention 4 is
An aluminum case that dissipates heat when the LED is lit,
A circuit cover that is an injection molded product that is made of a resin composition containing at least one selected from polybutylene terephthalate, polyphenylene sulfide, and polyamide resin, and that contains a lighting circuit that receives power through a base and lights the LED Composed of
Asperities are formed on the surface of the case, and the case and the circuit cover are integrated by the resin composition constituting the injection molded product entering the irregularities .
An insulating part that is configured by the resin composition and insulates the base and the case, a heat radiating part that is configured by the resin composition and is exposed to the outside of the case, and is configured by the resin composition and the base is fixed. The base fixing part is formed integrally .

The case for LED bulb of the present invention 5
An aluminum case that dissipates heat when the LED is lit,
An injection molded article composed of a resin composition containing at least one selected from polybutylene terephthalate, polyphenylene sulfide, and polyamide resin;
It is composed of an aluminum circuit cover that houses a lighting circuit that receives power through a base and turns on the LED,
Concavities and convexities are formed on the case surface and the circuit cover surface, and the resin composition constituting the injection-molded product penetrates into the concavities and convexities on both the case surface and the circuit cover surface. The injection molded product and the circuit cover are integrated ,
An insulating part that is configured by the resin composition and insulates the base and the case, a heat radiating part that is configured by the resin composition and is exposed to the outside of the case, and is configured by the resin composition and the base is fixed. The base fixing part is formed integrally .

  According to the present invention, heat conduction from the circuit cover to the case can be facilitated, and heat can be prevented from staying around the lighting circuit.

FIG. 1 is a longitudinal sectional view of an LED bulb according to the first embodiment. FIG. 2 is a diagram showing a PPS-aluminum model used in a heat conduction simulation experiment. FIG. 3 is a diagram showing the state of the joint surface in the PPS-aluminum model. FIG. 4 is a diagram showing the density, specific heat, and thermal conductivity of each material set in the PPS-aluminum model. FIG. 5 is a graph showing the temperature distribution in the PPS-aluminum model. FIG. 6 is a longitudinal sectional view of an LED bulb according to the second embodiment.

  Hereinafter, an LED bulb according to an embodiment of the present invention will be described with reference to the drawings.

[LED bulb according to the first embodiment]
FIG. 1 is a longitudinal sectional view of an LED bulb according to a first embodiment of the present invention. As shown in FIG. 1, the LED bulb 1 includes a substrate 11 on which a plurality of LEDs 10 serving as a light source are mounted, a lighting circuit 15 that receives power through a base 40 and lights the LED 10, and a circuit cover that houses the lighting circuit 15. 31 and a case 20 made of aluminum that dissipates heat when the LED 10 is turned on and is integrated with the circuit cover 31.

  An LED 10 shown in FIG. 1 is a semiconductor light emitting element that emits visible light, and a plurality of LEDs 10 are mounted on a substrate 11. As the substrate 11, for example, a resin material such as a glass epoxy material, a ceramic material, or the like is used, but it is preferable to use a material having high thermal conductivity. A wiring pattern (not shown) on which a plurality of LEDs 10 are mounted is formed on the mounting surface of the substrate 11. With this wiring pattern, the plurality of LEDs 10 are connected by a predetermined connection method. The wiring pattern and the lighting circuit 15 are connected by a lead wire (not shown).

  The base 12 is made of a metal material (for example, aluminum) having excellent thermal conductivity. The base 12 mounts the substrate 11 on which the LEDs 10 are mounted, and closes the other end of a cylindrical case 20 described later. The base 12 is fitted into the other end of the case 20, and the base 12 on which the substrate 11 is mounted is fixed to the inner peripheral surface of the case 20 with a heat conductive adhesive or the like. In this example, the taper portion 21 of the case 20 has a cylindrical shape having a predetermined taper angle, and the base 12 has a disk shape having the same taper angle. Therefore, the base 12 is positioned at a position where the diameter of the base 12 matches the inner diameter of the case 20. A plurality of stoppers may be formed on the inner peripheral surface of the case 20, and the base 12 press-fitted from the other end of the case 20 may be positioned by the stopper.

  A recess 12a for placing the substrate 11 is formed on the front side of the base 12, and the substrate 11 is attached to the base 12 in a state where the bottom surface of the recess 12a and the substrate 17 are in contact with each other. The substrate 11 is attached to the base 12 by, for example, a method of directly fixing with a fixing screw or a method of applying an attaching force with a leaf spring or the like. The substrate 12 can be easily and accurately positioned by the recess 12a. The base 12 includes a through hole 12b that penetrates in the thickness direction. Two lead wires from the lighting circuit 15 are electrically connected to the wiring pattern of the substrate 11 through the through holes 34a and 34a of the lid 34 and the through holes 12b and 12b of the base 12 described later. . In this example, two through holes 12b are provided, and lead wires pass through each. However, only one through hole may be provided, and two lead wires may be passed through the through hole.

  The lighting circuit 15 is composed of an electronic component (not shown) for lighting the LED 10, and converts the AC voltage (for example, 100V) supplied through the base member 40 into a DC voltage (for example, 24V) to the LED 10. Supply. The lighting circuit 15 includes, for example, a rectification / smoothing circuit, a DC / DC converter, and the like.

  The case 20 has a cylindrical shape as shown in FIG. 1, has an outer diameter that gradually decreases from the other end to the one end, the base 12 is attached to the other end, and the injection molding portion 30 is provided at one end. A base 40 is provided. The case 20 houses a circuit cover 31 therein, and the lighting circuit 15 is stored in the circuit cover 31. The case 20 has a cylindrical wall 21 and a bottom wall 22 provided at one end of the cylindrical wall 21, and a through hole 24 is provided in a central portion (including the central axis of the cylindrical portion) of the bottom wall 22. .

  The cylindrical wall 21 has a tapered shape in which the inner diameter gradually decreases when the cylindrical wall 21 moves from the other end (the globe side) to the one end (the base side) along the central axis of the cylindrical wall 21. The heat generated when the LED 10 is turned on is transmitted from the substrate 11 to the base 12 and from the base 12 to the case 20 and is mainly released from the case 20 to the outside air. That is, it can be said that the case 20 has a heat radiating function that radiates heat generated when the LED 10 is turned on to the outside air, and the base 12 has a heat transfer function that transfers the heat of the substrate 11 to the case 20.

  The injection molding part 30 includes a circuit cover 31 that houses the lighting circuit 15, an insulating part 32 that is interposed between the case 20 and the base 40 and insulates between them, and a spiral shape into which the base 40 is screwed. The base fixing part 33 is used. The circuit cover 31, the insulating portion 32, and the base fixing portion 33 are integrally formed by injection molding. Here, in the present embodiment, the insulating portion 32 is exposed to the outside (downward) of the case 20 and has a heat radiation function for radiating the heat transmitted to the circuit cover 31 into the outside air.

  The circuit cover 31 is formed in a cylindrical shape having an upper end opened and a part of the lower end closed, and the upper end opening is closed by a lid 34. The bottom surface 31 b excluding the lower center portion of the circuit cover 31 covers a part of the top surface of the bottom wall 22 in the case 20. Further, the circuit cover 31 has a protruding cylindrical portion 31 c that is continuous with the insulating portion 32 below. The protruding cylinder portion 31 c is a portion that protrudes downward from the bottom surface 31 b of the circuit cover 31, passes through the outermost part of the through hole 24, and continues to the insulating portion 32. It should be noted that not all of the lighting circuit 15 may be accommodated in the circuit cover 31 and only a part of the lighting circuit 15 may be accommodated. For example, the other part of the lighting circuit 15 may be accommodated inside the protruding cylinder part 31c, the cylindrical insulating part 32, and the base fixing part 33 (near the central axis of the LED bulb 1).

  The lid 34 has a bottomed cylindrical shape, and the cylinder portion is externally fitted to the upper end portion of the circuit cover 31 so that the lid portion closes the opening of the circuit cover 31. That is, the inner diameter of the cylindrical portion of the lid body 34 corresponds to the outer diameter of the upper end portion of the circuit cover 31, and the cylindrical inner peripheral surface of the lid body 34 with the lid body 34 and the circuit cover 31 assembled, The upper end part outer peripheral surface of the circuit cover 31 contacts. Note that the lid 34 and the circuit cover 31 may be fixed by, for example, an adhesive, or may be fixed by an engaging means in which the engaging portion and the engaged portion are combined. It may be provided and screwed, or the cylindrical inner diameter of the lid 34 may be smaller than the outer diameter of the upper end of the circuit cover 31 and fixed by fitting.

  The lid 34 is preferably formed of a material having a small specific gravity, for example, a resin such as PBT, for weight reduction. The lid portion of the lid body 34 is provided with two through holes 34a through which lead wires for wiring between the lighting circuit 15 and the substrate 11 pass. Each through hole 34 a is provided at a position corresponding to the through hole 12 b of the base 12. Here, for example, a substrate holder made of a locking claw or the like is provided on the back surface side (the bottom surface side of the lid portion) of the lid 34, and the substrate on which the electronic components constituting the lighting circuit 15 are mounted is provided by this base plate holder. It is preferable that the circuit cover 31 is assembled with the two lead wires (output-side lead wires) from the board being passed through the through holes 34a and 34a, respectively, while being fixed to the lid 34. Note that the number of through holes provided in the lid 34 may be one, or two lead wires may be passed through one through hole.

  The insulating portion 32 having a predetermined thickness covers the bottom surface of the bottom wall 22 and insulates the bottom wall 22 from the base 40. The insulating portion 32 is exposed below the case 20 and dissipates heat conducted from the circuit cover 31 to the insulating portion 32 into the outside air. Thus, the insulation part 32 of this embodiment has a heat dissipation function, and can increase the heat dissipation effect in a small space. Further, as in the present embodiment, a part of the bottom wall 22 is brought into close contact with the bottom surface 31 b of the circuit cover 31 and the top surface of the insulating portion 32, so that the heat transmitted to the circuit cover 31 and the insulating portion 32 from the circuit cover 31. The thermally conducted heat is transmitted to the case 20 and is radiated into the outside air.

  A base fixing portion 33 is provided below the insulating portion 32. The base 40 and the injection molding part 30 are fixed by screwing the base 40 onto the outer periphery of the base fixing part 33. The base 40 can be connected to a socket for general lighting bulbs such as E17 type and E26 type, for example, and is provided on a shell 41 that is fitted and fixed to the base fixing portion 33, and is provided on one end side of the shell 41. It has an insulating part 42 and an eyelet 43 provided on the top of the insulating part 42. A lead wire (not shown) drawn from the input side of the lighting circuit 15 is connected to the shell 41 and the eyelet 43.

  The globe 50 has translucency, and is formed in a substantially hemispherical shape having an opening at the end 50a, for example, by a material such as transparent glass or synthetic resin. And the edge part 50a is fitted inside the taper part 21 of the case 20, for example, is attached by the adhesive fixation by adhesives, such as a silicone resin and an epoxy resin. Thereby, the plurality of LEDs 10 are positioned at the opening of the globe 50 and are covered with the globe 50.

  As described above, the shell 41 and the eyelet 43 of the base 40 are electrically connected to the input side of the lighting circuit 15 by wiring, and the wiring connected to the output side of the lighting circuit 15 is connected to the through hole 34a, 34a and the through holes 12b and 12b of the base 12 are electrically connected to the wiring pattern of the substrate 11. When the base 40 is supplied with power, the lighting circuit 15 operates and a predetermined DC voltage (for example, 24V) is output. A DC voltage is applied to the LED 10 mounted on the substrate 11, the LED 10 is turned on, and visible light (for example, white light) is emitted from the LED 10.

  The heat generated when the LED 10 is turned on is thermally conducted to the substrate 11, is conducted from the substrate 11 to the base 12, and is further conducted from the base 12 to the case 20 to be radiated into the air. Further, part of the heat generated when the LED 10 is turned on is transmitted to the circuit cover 31 through the air layer, and part of the heat generated by the lighting circuit 15 itself is also transmitted to the circuit cover 31. The heat transmitted to the circuit cover 31 is radiated from the insulating portion 32 into the outside air, or is conducted from the insulating portion 32 to the case 20 and radiated into the outside air, so that the heat retention in the lighting circuit 15 is suppressed. can do.

  In the present embodiment, the case 20 and the circuit cover 31 are joined at the base side end portion (bottom wall 22) of the case 20, and the base 12 and the lid 34, and the cylinder portion 21 and the circuit cover 21 are connected. An air layer is provided between the two. That is, the heat generated when the LED 10 is turned on is prevented from being directly conducted to the circuit cover 21 before being radiated from the tube portion 21.

(Thermal conductivity between resin molded part and aluminum)
The above-described injection molding part 30 is formed by integrally molding a circuit cover 31 provided inside the case 20, and an insulating part 32 and a base fixing part 33 provided outside the case 20. The injection molded part 30 in the present embodiment is made of a crystalline thermoplastic resin, and is selected from, for example, polybutylene terephthalate (hereinafter referred to as PBT), polyphenylene sulfide (hereinafter referred to as PPS), and polyamide resin. A resin composition mainly containing seeds or more is preferred. Since the case 20 is made of aluminum, if the thermal conductivity from the injection molding part 30 to the case 20 is good, the heat around the lighting circuit 15 is efficiently radiated to the outside air.

The present inventors conducted a simulation experiment on the thermal conductivity between aluminum and PPS. As shown in FIG. 2, the simulation was performed by changing the state of the joint surface when the aluminum part having the same shape as the 0.2 mm × 1.0 mm PPS part was joined. Here, the temperature at each position of the PPS portion and the aluminum portion when a heat flux of 3 W / cm ² was generated in the direction from the left end to the right end of the PPS portion was calculated. Note that the upper and lower surfaces of the PPS portion and the aluminum portion (including the bonding surface) were both set as heat insulating surfaces.

As shown in FIG. 3, there are the following four states of the joint surfaces set in this experiment.
(A) A state in which unevenness is provided on both the PPS side bonding surface and the aluminum side bonding surface, and the both unevennesses mesh with each other and are in close contact with each other without a gap. Here, the width of the unevenness was 0.01 mm, and the height difference was 0.005 mm.
(B) A state in which both of the PPS side bonding surface and the aluminum side bonding surface are ideal flat surfaces having no irregularities, and both the bonding surfaces are in close contact with each other.
(C) A state in which an adhesive layer having a thickness of 0.1 mm is interposed between the PPS side bonding surface and the aluminum side bonding surface.
(D) A state in which an air layer having a thickness of 0.1 mm is interposed between the PPS side bonding surface and the aluminum side bonding surface.
In this experiment, the density, specific heat, and thermal conductivity of PPS, aluminum, the adhesive that constitutes the adhesive layer, and the air that constitutes the air layer were set as shown in FIG.

  FIG. 5 is a graph showing the temperature distribution of each part in the PPS-aluminum model shown in FIG. 2, and shows four distribution states corresponding to the states ((a) to (d)) of the respective joint surfaces. . In the horizontal axis (position (m)) in FIG. 5, the central portion of the joint surface is 0 m, the minus direction indicates the PPS side, and the plus direction indicates the aluminum side. As shown in FIG. 5, in the case of (d) provided with an air layer, the temperature at the left end (−0.001 m) of the PPS portion is 287 ° C., which is the highest. In the case of (c) provided with an adhesive layer, the temperature at the left end of the PPS part was 193 ° C. In the case (b) in which the flat surfaces were brought into close contact with each other, the temperature at the left end of the PPS part was 169 ° C., and in the case (a) in which the uneven surfaces were brought into close contact with each other, the temperature at the left end of the PPS part was 167 ° C. From this result, it was confirmed that there is no significant difference in thermal conductivity between the case where the joint surface is a flat surface (a) and the case where the joint surface is an uneven surface having a larger joint area than the flat surface (b). However, it has been confirmed that when the adhesive layer is provided, the thermal conductivity from the PPS part to the aluminum part is lowered, and when the air layer is provided, the heat stays in the PPS part.

  From the above experimental results, it is preferable from the viewpoint of improving the heat radiation performance that the flat surfaces or the concavo-convex surfaces of the case 20 and the injection molded part 30 (the circuit case 31 and the insulating part 32) are joined without using an adhesive. However, it is impossible to form an ideal flat surface. Normally, even if the flat surfaces are brought into close contact with each other, it is not a surface contact but a point contact, and an air layer is mostly interposed. Become.

  On the other hand, even if an uneven surface is formed on the case 20 and the injection-molded portion 30, it is difficult to bond them together without using an adhesive. Even if the case 20 and the injection-molded part 30 are brought into close contact with each other and integrated by screwing, an air layer can be easily interposed due to loosening of screws or the like. On the other hand, the present inventors form irregularities on the surface of the aluminum case 20 by NMT (Nano molding technology), which will be described later, and allow the resin composition constituting the injection molded portion 30 to enter these irregularities. It was cured in the state. That is, the unevenness of the surface of the case 20 and the unevenness of the injection molding part 30 were brought into close contact with each other to integrate them.

(Outline of NMT)
NMT is a technology developed by the present inventors, and is a known technology as shown in Patent Documents 2 and 3. NMT is a joining technique between aluminum and a resin composition. After a predetermined surface treatment is applied to aluminum, it is inserted into an injection mold, and a molten engineering resin is injected into the mold. The resin part is molded at the same time, and the molded product and aluminum are joined together (hereinafter referred to as “injection joining” for short).

As requirements for NMT, there are two conditions for aluminum and one condition for the resin composition. Two conditions of aluminum are shown below.
(1) The aluminum surface is covered with ultrafine irregularities having a period of 20 to 80 nm (preferably 20 to 50 nm), or ultrafine recesses or ultrafine protrusions having a diameter of 20 to 80 nm (preferably a diameter of 20 to 50 nm). about. As an index, RSm is preferably covered with ultra fine irregularities having a thickness of 20 nm to 80 nm. Moreover, Rz may be covered with an ultrafine concave portion or an ultrafine convex portion having a diameter of 20 to 80 nm. Furthermore, it may be covered with ultra-fine irregularities with RSm of 20 nm to 80 nm and Rz of 20 to 80 nm. RSm is the average length of contour curve elements defined in Japanese Industrial Standards (JIS B 0601: 2001, ISO 4287: 1997), and Rz is Japanese Industrial Standards (JIS B 0601: 2001, ISO 4287: 1997) Is the maximum height specified. Here, the surface layer of aluminum is a thin layer of aluminum oxide, and the thickness thereof is 3 nm or more.
(2) Ammonia, hydrazine, or a water-soluble amine compound is chemically adsorbed on the aluminum surface before injection joining.

On the other hand, the conditions of the resin composition are as follows.
(3) The main component is a hard crystalline thermoplastic resin that can react with a broadly defined amine compound such as ammonia, hydrazine, or water-soluble amines at 150 to 200 ° C. Specifically, it is a resin composition containing PBT, PPS, polyamide resin or the like as a main component. For example, a commercially available PPS resin “SGX120” (manufactured by Tosoh Corporation) can be suitably used.

  Although the surface treatment method of aluminum in NMT is disclosed in Patent Documents 2 and 3, an outline thereof will be described. A shaped aluminum part (for example, the case 20 in the present embodiment) is put into a degreasing tank to perform a degreasing operation. Next, the surface layer is dissolved by immersing in a caustic soda aqueous solution having a concentration of several percent, and the dirt that cannot be removed by the degreasing operation is removed together with the aluminum surface layer. Next, it is immersed in an aqueous nitric acid solution having a concentration of several percent to neutralize and remove sodium ions and the like adhering to the surface in the previous operation. The operation up to this point is an operation for making the surface of the aluminum part a clean surface that is structurally and chemically stable. If the aluminum parts are clean and free from dirt and corrosion, these pretreatment operations can be omitted.

  The important processes in NMT are as follows. In NMT, an aluminum part is immersed in an aqueous solution of a water-soluble amine compound under appropriate conditions, and the surface of the part is etched to form ultra fine irregularities with a period of 20 to 80 nm, and the amine compound is chemisorbed simultaneously. For example, by performing ultrafine etching in which an aluminum part is immersed in an aqueous hydrazine solution having a concentration of 1 to several percent at 45 to 65 ° C. for 1 minute to several minutes, ultrafine irregularities with a period of 20 to 40 nm are formed on the aluminum surface. It is formed. After ultra-fine etching, the aluminum part is thoroughly washed with ion-exchanged water and dried at 50 to 70 ° C., which is suitable for injection joining in which chemical adsorption of hydrazine is recognized. This is the surface treatment method of “NMT”.

(Creation of case for LED bulb according to the first embodiment)
The case 20 subjected to the above surface treatment is inserted into an injection mold having a mold temperature of 145 ° C., and the above-described resin (for example, PPS resin “SGX120”) is injected onto the surface thereof. As a result, the injection-molded part 30 (the circuit cover 31, the insulating part 32, and the base fixing part 33 are integrated) is molded, and the resin composition constituting this invades the ultra-fine irregularities on the aluminum surface. A case for an LED bulb that is a cured integrated product is obtained.

  This LED bulb case is a component in which an aluminum case 20, a circuit cover 31, an insulating portion 32, and a base fixing portion 33 are integrated. By adopting such a structure, there is no need for a screwing mechanism or an adhesive for fixing the circuit cover 31, the insulating part 32, the base fixing part 33, and the case 20, so the structure and assembly process of the LED bulb can be reduced. It can be simplified. And since it has an uneven structure that promotes heat conduction from the injection molding part 30 to the case 20, heat retention in the circuit cover 31 can be prevented.

[LED bulb according to the second embodiment]
Next, the LED bulb according to the second embodiment will be described with respect to parts different from the first embodiment. FIG. 6 is a longitudinal sectional view of an LED bulb according to the second embodiment of the present invention. The case 20 includes a tapered portion 21 and an end portion 23 that protrudes downward from the lower end of the tapered portion 21. The injection molding part 30 includes an insulating part 32 and a base fixing part 33. In the second embodiment, the lighting circuit 15 is housed in an aluminum circuit cover 35. The circuit cover 35 has a substantially cylindrical shape with upper and lower openings, and the lighting circuit 15 is stored in the circuit cover 35. In addition, not all the lighting circuit 15 may be stored in the circuit cover 35, but only a part of the lighting circuit 15 may be stored. For example, the other part of the lighting circuit 15 may be accommodated inside the cylindrical insulating portion 32 and the base fixing portion 33 (near the central axis of the LED bulb 1).

  Here, the end portion 35a of the aluminum circuit cover 35 and the end portion 23 of the aluminum case 20 are integrated together with the insulating portion 32 constituting the resin molded portion 30 by, for example, the above-described injection joining by NMT. . For example, the LED bulb case in the second embodiment is created as follows.

(Creation of a case for an LED bulb according to the second embodiment)
The case 20 and the circuit cover 35 subjected to the surface treatment for NMT described above are inserted into an injection mold having a mold temperature of 145 ° C., and the resin (for example, PPS) is inserted into the case end 23 and the circuit cover end 35a. Resin “SGX120”) is injected. As a result, the injection-molded part 30 (in which the insulating part 32 and the base fixing part 33 are integrated) is molded, and the resin composition constituting this invades the ultra-fine irregularities on the surfaces of the end parts 23 and 35a made of aluminum. Thus, an LED bulb case which is an integrated product cured is obtained.

  This LED bulb case is a component in which an aluminum case 20 and an aluminum circuit cover 31 are integrally joined via an insulating portion 32, and a component in which the insulating portion 32 and the base fixing portion 33 are further integrated. It is. By adopting such a structure, there is no need for a screwing mechanism or an adhesive for fixing the circuit cover 31, the insulating part 32, the base fixing part 33, and the case 20, so the structure and assembly process of the LED bulb can be reduced. It can be simplified.

  As mentioned above, although embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to this form, and can change within the range which does not deviate from the objective of this invention and the meaning. In the present embodiment, irregularities are formed on the aluminum surface by NMT and bonded to the resin composition. However, other methods capable of forming irregularities and bonding to the resin composition may be used. For example, alumite treatment may be performed when unevenness is provided on the aluminum surface.

1 ... LED bulb 10 ... LED
DESCRIPTION OF SYMBOLS 11 ... Board | substrate 12 ... Base 15 ... Lighting circuit 20 ... Case 30 ... Resin molding part 31 ... Circuit cover 33 ... Base fixing | fixed part 35 ... Circuit cover 40 ... Base

Claims (5)

A substrate on which an LED is mounted;
A lighting circuit that receives power through the base and lights the LED;
A circuit cover that houses the lighting circuit;
An aluminum case that dissipates heat when the LED is lit;
An LED bulb comprising:
The circuit cover is an injection-molded article composed of a resin composition containing at least one selected from polybutylene terephthalate, polyphenylene sulfide, and polyamide resin,
Asperities are formed on the surface of the case, and the circuit cover and the case are integrated by the resin composition constituting the injection molded product entering the irregularities.
An insulating part that is configured by the resin composition and insulates the base and the case, a heat radiating part that is configured by the resin composition and is exposed to the outside of the case, and is configured by the resin composition and the base is fixed. An LED bulb characterized in that a cap fixing part is integrally formed. A substrate on which an LED is mounted;
A lighting circuit that receives power through the base and lights the LED;
An aluminum circuit cover that houses the lighting circuit;
An aluminum case that dissipates heat when the LED is lit;
An LED bulb comprising:
It is composed of a resin composition containing at least one selected from polybutylene terephthalate, polyphenylene sulfide, and polyamide resin, and has an injection molded product that comes into contact with the circuit cover and the case,
Concavities and convexities are formed on the circuit cover surface and the case surface, and the resin composition constituting the injection-molded product penetrates into the concavities and convexities on both the circuit cover surface and the case surface. The circuit cover and the case are integrated,
An insulating part that is configured by the resin composition and insulates the base and the case, a heat radiating part that is configured by the resin composition and is exposed to the outside of the case, and is configured by the resin composition and the base is fixed. An LED bulb characterized in that a cap fixing part is integrally formed. The LED bulb according to claim 1 or 2,
The LED bulb characterized in that the insulating part and the heat dissipation part are the same part. An aluminum case that dissipates heat when the LED is lit,
A circuit cover that is an injection molded product that is made of a resin composition containing at least one selected from polybutylene terephthalate, polyphenylene sulfide, and polyamide resin, and that contains a lighting circuit that receives power through a base and lights the LED Composed of
Asperities are formed on the surface of the case, and the case and the circuit cover are integrated by the resin composition constituting the injection molded product entering the irregularities .
An insulating part that is configured by the resin composition and insulates the base and the case, a heat radiating part that is configured by the resin composition and is exposed to the outside of the case, and is configured by the resin composition and the base is fixed. A case for an LED bulb characterized in that the base fixing portion is integrally formed . An aluminum case that dissipates heat when the LED is lit,
An injection molded article composed of a resin composition containing at least one selected from polybutylene terephthalate, polyphenylene sulfide, and polyamide resin;
It is composed of an aluminum circuit cover that houses a lighting circuit that receives power through a base and turns on the LED,
Concavities and convexities are formed on the case surface and the circuit cover surface, and the resin composition constituting the injection-molded product penetrates into the concavities and convexities on both the case surface and the circuit cover surface. The injection molded product and the circuit cover are integrated ,
An insulating part that is configured by the resin composition and insulates the base and the case, a heat radiating part that is configured by the resin composition and is exposed to the outside of the case, and is configured by the resin composition and the base is fixed. A case for an LED bulb characterized in that the base fixing portion is integrally formed .