Lighting device

Abstract

To provide a lighting device capable of suppressing stress applied to a substrate while suppressing reduction in total luminous flux even when the lighting device is miniaturized.SOLUTION: The lighting device 1 includes a substrate 10 having a first surface 11 and a second surface 12 opposite to the first surface 11, a plurality of light sources 20 disposed on the first surface 11 of the substrate 10, a heat sink 40 located on the second surface 12 side of the substrate 10, and a housing 50 accommodating the substrate 10 and the heat sink 40, wherein the substrate 10 and the housing 50 are connected to each other, the substrate 10 and the heat sink 40 are connected to each other, and the housing 50 and the heat sink 40 are independent of each other without being connected to each other.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a lighting device. [Background technology]

[0002] Semiconductor light-emitting elements such as light-emitting diodes (LEDs) are used as light sources for a variety of products due to their small size, high efficiency, and long life. For example, LED lighting, which is a lighting device using LEDs, is known (see, for example, Patent Document 1).

[0003] A well-known example of LED lighting is a ceiling light that is installed on a ceiling. Conventionally, a known type of ceiling light includes a metal fixture body, a circuit board attached to the fixture body, multiple LED elements mounted on the board, a translucent cover that covers the multiple LED elements, and an adapter that is held in a holder attached to the fixture body and connected to a ceiling hook body installed on the ceiling. A connector is provided between the adapter and the circuit board, and the adapter and the circuit board are electrically connected via the connector. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-174710 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the conventional lighting fixture disclosed in Patent Document 1, the substrate is fixed to both the fixture body and the holder. Specifically, the substrate on which the LED elements are mounted is directly connected to the metal fixture body and fixed to the fixture body with screws, and is also fixed to a holder attached to the fixture body with screws. Therefore, the stack-up tolerance between the substrate, fixture body, and holder may cause stress on the substrate, resulting in distortion and resulting in malfunctions such as damage to electronic components such as LED elements mounted on the substrate. In particular, when lighting fixtures are made smaller, the distance between the screws becomes shorter, etc., and the stress on the substrate due to the stack-up tolerance increases.

[0006] Therefore, it is conceivable to configure the circuit board and the fixture body so as not to directly connect them, but doing so would reduce the heat dissipation capability of the heat generated by the LED elements, reducing the light output of the LED elements and the total luminous flux of the lighting fixture. Furthermore, when a lighting fixture is made smaller, the mounting density of multiple LED elements increases, further reducing the heat dissipation capability of the LED elements. Therefore, it is conceivable to reduce the number of mounted LED elements so as not to reduce the heat dissipation capability of each LED element, but doing so would result in a reduction in the total luminous flux of the lighting fixture.

[0007] The present invention has been made to solve such problems, and aims to provide a lighting device that can suppress the stress on the substrate while suppressing a decrease in total luminous flux. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, one aspect of the lighting device according to the present invention comprises a substrate having a first surface and a second surface opposite to the first surface, a plurality of light sources arranged on the first surface of the substrate, a heat sink located on the second surface side of the substrate, and a housing that houses the substrate and the heat sink, wherein the substrate and the housing are connected to each other, and the substrate and the heat sink are connected to each other, and the housing and the heat sink are independent of each other without being connected to each other. [Effects of the Invention]

[0009] According to the present invention, it is possible to suppress the stress applied to the substrate while suppressing a decrease in total luminous flux. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a state in which a lighting device according to an embodiment is installed on a ceiling. [Figure 2] FIG. 2 is an exploded perspective view of the lighting device according to the embodiment. [Figure 3] FIG. 3 is a cross-sectional view of the lighting device according to the embodiment. [Figure 4] FIG. 4 is a perspective view of the light source module, the heat sink, and the connector in the lighting device according to the embodiment, viewed from the first surface side of the substrate. [Figure 5] FIG. 5 is a perspective view of the light source module, the heat sink, and the connector in the lighting device according to the embodiment, viewed from the second surface side of the board. [Figure 6] FIG. 6 is a top view of a light source module used in the lighting device according to the embodiment. [Figure 7] FIG. 7 is a rear view of the light source module used in the lighting device according to the embodiment. [Figure 8] FIG. 8 is an enlarged perspective cross-sectional view showing a part of the lighting device according to the embodiment. [Figure 9] FIG. 9 is a cross-sectional view of a lighting device of a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present invention. Therefore, the numerical values, components, the arrangement and connection of the components, steps, and the order of steps shown in the following embodiments are merely examples and are not intended to limit the present invention. Therefore, among the components in the following embodiments, components that are not described in the independent claims that represent the highest concept of the present invention will be described as optional components.

[0012] It should be noted that the drawings are schematic diagrams and are not necessarily strict illustrations. In addition, in the drawings, substantially the same components are denoted by the same reference numerals, and redundant explanations will be omitted or simplified.

[0013] (Embodiment) The configuration of a lighting device 1 according to an embodiment will be described with reference to Figs. 1 to 5. Fig. 1 is a diagram showing a state in which lighting device 1 according to an embodiment is installed on a ceiling 100. Fig. 2 is an exploded perspective view of lighting device 1. Fig. 3 is a cross-sectional view of lighting device 1. Note that Fig. 3 shows only the cross-sectional portion of lighting device 1. Figs. 4 and 5 are perspective views of a light source module 2, a heat sink 40, and a connector 70 in lighting device 1 according to an embodiment. Fig. 4 is a perspective view when viewed from the first surface 11 side of substrate 10, and Fig. 5 is a perspective view when viewed from the second surface 12 side of substrate 10.

[0014] The lighting device 1 shown in FIG. 1 is installed at a predetermined location in a building. Specifically, the lighting device 1 is installed on a predetermined construction material such as a ceiling or wall in a room of a building such as a facility, a building, a store, or a residence. The lighting device 1 in this embodiment is a lighting fixture installed on a ceiling. That is, the lighting device 1 is a ceiling light, and as shown in FIG. 1, it is installed on a ceiling 100 of a building. Specifically, the lighting device 1 is installed on the ceiling 100 by being attached to a hook ceiling body 110 (power supply unit) installed on the ceiling 100. The hook ceiling body 110 is a power supply unit for supplying power to the lighting device 1, and is electrically connected to a commercial power source (system power supply) via an electric wire or the like on the back side of the ceiling 100, for example. The lighting device 1 can receive AC power from the commercial power source by being attached to the hook ceiling body 110. The lighting device 1 is an LED light using LEDs.

[0015] In this embodiment, the lighting device 1 is a small lighting fixture, and the external size of the lighting device 1 is φ300 mm or less. As an example, the external size of the lighting device 1 is φ240 mm.

[0016] 1 to 3, the lighting device 1 in this embodiment includes a substrate 10, a plurality of light sources 20, a plurality of circuit elements 30, a heat sink 40, a housing 50, an adapter 60, a connector 70, and a light-transmitting cover 80. In this embodiment, the housing 50 and the light-transmitting cover 80 constitute the outer casing of the lighting device 1.

[0017] As shown in FIGS. 2 to 5, the substrate 10 has a first surface 11 and a second surface 12 opposite to the first surface 11. The substrate 10 is a mounting substrate on which the light source 20 and the circuit element 30 are mounted. The substrate 10 is, for example, a printed wiring board on which wiring is formed in a predetermined pattern. The wiring formed on the substrate 10 is, for example, metal wiring made of a thin metal film such as copper or silver. In this embodiment, the substrate 10 is a double-sided wiring board on which wiring is formed on both the first surface 11 and the second surface 12. Note that a resist made of an insulating resin material may be formed on the surface of the substrate 10 so as to cover the wiring in order to protect the wiring and ensure a dielectric strength voltage.

[0018] The base material constituting the substrate 10 may be a resin substrate made of an insulating resin material, a ceramic substrate made of a sintered body of a ceramic material such as alumina, or a metal-based substrate obtained by applying an insulating coating to the surface of a metal substrate made of a metal material such as aluminum or copper.

[0019] In this embodiment, the base material constituting the substrate 10 is an insulating resin substrate. Examples of resin substrates that can be used include glass epoxy substrates (CEM-3, FR-4, etc.) made of glass fiber and epoxy resin, paper phenol substrates (FR-1, FR-2) made of kraft paper or the like and phenol resin, paper epoxy substrates (FR-3) made of paper and epoxy resin, and polyimide substrates made of polyimide or the like. The substrate 10 may be a rigid substrate or a film-like flexible substrate. The thickness of the substrate 10 is, for example, 0.5 mm to 2 mm, but is not limited to this.

[0020] The shape of the substrate 10 in plan view is not annular. In other words, the substrate 10 is not annular with an opening in the center. As shown in FIG. 2, in this embodiment, the shape of the substrate 10 in plan view is a substantially circular disk. The substrate 10 may be divided into multiple pieces. In other words, the substrate 10 may be composed of multiple substrates.

[0021] The planar shape of the substrate 10 may be a circular ring having a central opening. In this case, the substrate 10 may be divided into multiple pieces. For example, the substrate 10 may be composed of multiple substrates, each of which is arc-shaped and arranged in a circular ring shape.

[0022] As shown in FIGS. 2 to 4, the substrate 10 is provided with a first through hole 10a and a second through hole 10b. A first screw M1 is inserted into the first through hole 10a, and a second screw M2 is inserted into the second through hole 10b. In this embodiment, a plurality of first through holes 10a and a plurality of second through holes 10b are provided. Specifically, four first through holes 10a and four second through holes 10b are provided. The first through holes 10a are provided at positions closer to the outer periphery than the second through holes 10b.

[0023] A plurality of light sources 20 are arranged on the first surface 11 of the substrate 10. The plurality of light sources 20 are electrically connected by wiring formed on the first surface 11 of the substrate 10. Note that the manner of connection of the plurality of light sources 20 (series connection, parallel connection, a combination of series connection and parallel connection, etc.) is not particularly limited.

[0024] Each of the light sources 20 is an LED light source configured by an LED. In this embodiment, each of the light sources 20 is an individually packaged surface mount device (SMD) type LED element. Therefore, the light sources 20 are solder-mounted on the first surface 11 of the substrate 10.

[0025] The light source 20, which is a surface-mounted LED element, includes a package (container) made of white resin with a recess, an LED chip primarily mounted on the bottom surface of the recess, and a sealing member encapsulated in the recess. The sealing member is made of a light-transmitting resin material such as silicone resin. The sealing member may also be a phosphor-containing resin that contains a wavelength conversion material such as a phosphor.

[0026] An LED chip is an example of a semiconductor light-emitting device that emits light using a specified DC power, and is a bare chip that emits monochromatic visible light. The LED chip is, for example, a blue LED chip that emits blue light when powered. In this case, to obtain white light, the sealing material contains a yellow phosphor such as YAG (yttrium aluminum garnet), which fluoresces using the blue light from the blue LED chip as excitation light.

[0027] Thus, light source 20 in this embodiment is a BY-type white LED light source composed of a blue LED chip and a yellow phosphor. Specifically, the yellow phosphor absorbs a portion of the blue light emitted by the blue LED chip, becomes excited, and emits yellow light. This yellow light is mixed with the blue light not absorbed by the yellow phosphor to produce white light. Note that the sealing member may contain a red phosphor or a green phosphor in addition to the yellow phosphor.

[0028] The substrate 10 and the plurality of light sources 20 constitute a light source module 2. The light source module 2 is a light-emitting unit of the lighting device 1, and emits, for example, white light as the main illumination light. Specifically, each of the plurality of light sources 20 emits white light as the main illumination light of the lighting device 1. As an example, each of the plurality of light sources 20 emits white light with a color temperature of 6200 K. In addition, in this embodiment, the light source module 2 also has a plurality of circuit elements 30 that constitute a power supply circuit. In other words, the light source module 2 is a module with an integrated power supply.

[0029] The multiple light sources 20 emit light using power supplied from a power supply circuit composed of multiple circuit elements 30. The power supply circuit is a power supply unit that generates power for emitting light to the multiple light sources 20 and supplies the power to the light sources 20. External AC power is supplied to the power supply circuit from the hooking ceiling body 110 via an adapter 60 and a connector 70. The power supply circuit converts the received AC power into DC power of a predetermined level by rectifying, smoothing, stepping down, etc. The DC power generated by the power supply circuit is supplied to the multiple light sources 20, causing the multiple light sources 20 to emit light. The power supply circuit constitutes, for example, a constant current circuit, but the current supplied to the light sources 20 may also be limited by a constant voltage circuit and a resistor.

[0030] The multiple circuit elements 30 that make up the power supply circuit are, for example, capacitive elements such as electrolytic capacitors and ceramic capacitors, resistive elements such as resistors, rectifier circuit elements, coil elements, choke coils (choke transformers), noise filters, diodes, integrated circuit elements (ICs), or semiconductor elements (FETs, etc.).

[0031] The plurality of circuit elements 30 may include not only power supply circuit elements constituting a power supply circuit, but also control circuit elements (such as a microcomputer) constituting a control circuit for controlling the light emission states of the plurality of light sources 20. The plurality of circuit elements 30 may also include not only power supply circuit elements and control circuit elements, but also circuit elements constituting other circuits. For example, the plurality of circuit elements 30 may include drive circuit elements constituting a dimming circuit or a boost circuit, or may include communication circuit elements (communication modules) constituting a communication circuit.

[0032] 4 and 5, the plurality of circuit elements 30 are arranged on a substrate 10. In other words, the substrate 10 is a common substrate shared by the light source 20 and the circuit elements 30, and the plurality of light sources 20 and the plurality of circuit elements 30 are arranged on the same substrate 10. Therefore, the substrate 10 is both a light source substrate on which the light source 20 is mounted, and a power supply substrate on which the plurality of circuit elements 30 that constitute the power supply circuit are mounted.

[0033] As shown in FIG. 5, in this embodiment, the circuit elements 30 with leads (lead-attached components) among the plurality of circuit elements 30 are arranged on the second surface 12 of the substrate 10. That is, the element body of the circuit element 30 with leads is arranged on the second surface 12 of the substrate 10, and the lead portions of the circuit element 30 with leads are solder-joined to the first surface 11 of the substrate 10. Also, as shown in FIG. 4, the surface-mounted circuit elements 30 (surface-mounted components) among the plurality of circuit elements 30 are mounted on the first surface 11 of the substrate 10, similar to the light source 20, and are solder-joined to the first surface 11. That is, both the circuit elements 30 with leads and the surface-mounted circuit elements 30 are solder-joined to the first surface 11 of the substrate 10, similar to the light source 20. Note that, for the circuit elements 30 with leads, solder is also formed in the through-holes of the substrate 10 through which the lead portions are inserted.

[0034] The plurality of circuit elements 30 are arranged in a ring shape on the substrate 10. Specifically, the plurality of circuit elements 30 are arranged in a ring shape with the center of the circle set at the center of the substrate 10. Furthermore, the plurality of light sources 20 are arranged in a ring shape on the substrate 10. Specifically, the plurality of light sources 20 are arranged in a ring shape with the center of the circle set at the center of the substrate 10. In this embodiment, the plurality of light sources 20 are arranged in a ring shape in multiple rows.

[0035] 6 and 7, the plurality of light sources 20 arranged on the first surface 11 of the substrate 10 are arranged on the inner and outer circumferential sides of the plurality of circuit elements 30 arranged in a ring shape on the second surface 12 of the substrate 10. FIG. 6 is a top view of the light source module 2, and FIG. 7 is a rear view of the light source module 2.

[0036] In this way, by arranging the plurality of light sources 20 not only on the outer periphery side but also on the inner periphery side of the plurality of circuit elements 30, illumination light can be emitted from the center of the illumination device 1, and therefore more uniform illumination light can be emitted compared to an illumination device in which the plurality of light sources 20 are arranged only on the outer periphery side of the plurality of circuit elements 30. In particular, in this embodiment, a mounting substrate having a shape other than annular (such as a circle) is used as the substrate 10, so that the light sources 20 can be easily mounted even in the center of the substrate 10. This makes it possible to prevent the illumination light emitted from the illumination device 1 from becoming dark in the center, and allows for more uniform illumination light to be emitted overall.

[0037] 6 and 7, the first surface 11 of the substrate 10 has a first region A1, a second region A2, and a third region A3. The first region A1 is the innermost region, the third region A3 is the outermost region, and the second region A2 is an intermediate region between the first region A1 and the third region A3.

[0038] In this embodiment, the first region A1 is an inner region of the plurality of circuit elements 30 arranged in an annular shape, and is an region where the first light sources 20a, which are some of the plurality of light sources 20 arranged in an annular shape, are arranged. In the first region A1, the plurality of first light sources 20a are arranged in a line. Furthermore, the plurality of first light sources 20a in the first region A1 are arranged at equal pitches.

[0039] The second area A2 is an area surrounding the first area A1, and is an area in which a plurality of circuit elements 30 are arranged in a ring shape. As shown in Fig. 6, the second area A2 does not include a light source 20 that emits main illumination light, but includes a light source 21 that serves as a night light.

[0040] The third region A3 is a region surrounding the second region A2, and is a region in which second light sources 20b, which are another part of the plurality of light sources 20, are arranged in a ring shape. In the third region A3, the plurality of second light sources 20b are arranged in multiple rows. Specifically, the plurality of second light sources 20b are arranged in two rows. Furthermore, the plurality of second light sources 20b in the third region A3 are arranged at an equal pitch in each row. Note that the arrangement pitch of the plurality of second light sources 20b in the third region A3 may differ from one row to another.

[0041] As shown in FIGS. 3 to 5, the light source module 2 configured as above is connected to a heat sink 40. Specifically, the substrate 10 of the light source module 2 is connected to the heat sink 40. That is, the substrate 10 and the heat sink 40 are connected to each other. In this embodiment, the heat sink 40 is in contact with the substrate 10. Specifically, the heat sink 40 is located on the second surface 12 side of the substrate 10, and the heat sink 40 is in contact with the second surface 12 of the substrate 10.

[0042] The heat sink 40 is a heat dissipation member that dissipates heat generated in the light source module 2, and is thermally coupled to the light source module 2. The heat sink 40 dissipates heat generated in the light source 20. In this embodiment, since a plurality of circuit elements 30 are also mounted on the substrate 10, the heat sink 40 may also dissipate heat generated by heat-generating components (such as coils or FETs) included in the plurality of circuit elements 30. As shown in FIG. 5, the heat sink 40 is configured to surround the plurality of circuit elements 30. The heat sink 40, which is a heat dissipation member, is preferably made of a metal such as aluminum or a material with high thermal conductivity such as a highly thermally conductive resin.

[0043] As shown in FIGS. 2 to 5, the heat sink 40 has a plate portion 41 and a tubular portion 42 extending from the outer peripheral end of the plate portion 41 to the side opposite to the substrate 10 side.

[0044] As shown in FIG. 3 , the plate portion 41 is located between the housing 50 and the board 10. Specifically, the plate portion 41 is located between the bottom 51 of the housing 50 and the board 10. As shown in FIG. 5 , in a top view, the plurality of light sources 20 are arranged in a position overlapping the plate portion 41. Specifically, among the plurality of light sources 20, the plurality of second light sources 20b arranged in the third region A3 of the board 10 are arranged in a position overlapping the plate portion 41. This allows heat generated by the plurality of second light sources 20b arranged in the third region A3 to be conducted to the plate portion 41 and efficiently dissipated. In particular, in this embodiment, the plurality of second light sources 20b in the third region A3 are mounted in multiple rows. However, even when the plurality of second light sources 20b are mounted in multiple rows, the heat generated by the plurality of second light sources 20b can be efficiently dissipated by the heat sink 40.

[0045] Note that, among the multiple light sources 20, the multiple first light sources 20a arranged in the first region A1 of the substrate 10 do not overlap the heat sink 40 in a top view. Therefore, the heat generated by the first light sources 20a arranged in the first region A1 cannot be dissipated as efficiently as the heat generated by the second light sources 20b arranged in the third region A3. For this reason, in the present embodiment, the arrangement pitch of the multiple first light sources 20a arranged in the first region A1 is larger than the arrangement pitch of the multiple second light sources 20b arranged in the third region A3. As a result, even if the first light sources 20a arranged in the first region A1 do not overlap the heat sink 40, the heat generated by the first light sources 20a can be dissipated with the same efficiency as the heat generated by the second light sources 20b arranged in the third region A3.

[0046] As shown in FIGS. 2 and 5 , the planar shape of the plate portion 41 is annular, having an opening 41a at a position overlapping with the holder portion 53 of the housing 50. In the present embodiment, the plate portion 41 is a circular plate member with a constant width. The board 10 is placed on the plate portion 41. Specifically, the second surface 12 of the board 10 is in contact with the plate portion 41. In this case, since the planar shape of the board 10 is circular rather than annular, the second surface 12 of the board 10 is exposed from the opening 41a of the board portion 41. As a result, even when the plate portion 41 is in contact with the second surface 12 of the board 10, the circuit element 30 can be mounted on the second surface 12 of the board 10 that is exposed from the plate portion 41.

[0047] As shown in Fig. 5, the cylindrical portion 42 surrounds the plurality of circuit elements 30. In other words, the plurality of circuit elements 30 mounted on the second surface 12 of the substrate 10 are surrounded by the cylindrical portion 42 and face the inner surface of the cylindrical portion 42. Furthermore, as shown in Fig. 3, the side wall portion 52 of the housing 50 is present on the outside of the cylindrical portion 42, and the cylindrical portion 42 faces the side wall portion 52 of the housing 50. In other words, the cylindrical portion 42 is surrounded by the side wall portion 52 of the housing 50, and the outer surface of the cylindrical portion 42 faces the inner surface of the side wall portion 52 of the housing 50.

[0048] As shown in Fig. 5, the tubular portion 42 is cylindrical. As shown in Fig. 3, in this embodiment, the cylindrical tubular portion 42 is inclined so that the opening diameter becomes smaller with increasing distance from the plate portion 41. The tubular portion 42 is inclined along the side wall portion 52 of the housing 50. Note that the tubular portion 42 may be cylindrical with a constant opening diameter.

[0049] The heat sink 40, which is made up of the plate portion 41 and the tubular portion 42, has a flat shape overall, and the height of the tubular portion 42 is smaller than the maximum opening diameter of the tubular portion 42 (that is, the diameter of the plate portion 41).

[0050] The heat sink 40 configured as described above is a press-molded product made of metal. For example, the heat sink 40 having the plate portion 41 and the tubular portion 42 can be formed by pressing a metal plate of a uniform thickness. In this case, the plate portion 41 and the tubular portion 42 are integrally formed. In this embodiment, a steel plate having a thickness of 0.4 mm and containing iron as its main component is used as the metal plate. Alternatively, the plate portion 41 and the tubular portion 42 may be formed as separate bodies and then joined by welding or the like to form the heat sink 40. The heat sink 40 may also be made of a metal material other than iron. For example, the heat sink 40 may be made of a metal material such as aluminum.

[0051] As shown in FIGS. 3 and 4, the heat sink 40 is fixed to the substrate 10 of the light source module 2. In this embodiment, a plate portion 41 of the heat sink 40 is fixed to the substrate 10. Specifically, as shown in FIGS. 3 and 8, a through hole 40a is formed in the plate portion 41 of the heat sink 40, and a first screw M1 inserted into a first through hole 10a of the substrate 10 is screwed into the through hole 40a of the heat sink 40, thereby fixing the plate portion 41 of the heat sink 40 to the substrate 10. FIG. 8 is an enlarged cross-sectional perspective view showing a portion of the lighting device 1. As shown in FIG. 8, the substrate 10 is sandwiched between the plate portion 41 of the heat sink 40 and the head of the first screw M1.

[0052] 2 and 8, the through-hole 40a of the heat sink 40 is provided at a position corresponding to the first through-hole 10a of the substrate 10. In other words, in a plan view, the through-hole 40a of the heat sink 40 and the first through-hole 10a of the substrate 10 are provided at positions that overlap each other.

[0053] 3, the housing 50 is a main body of the lighting device 1, and supports the light source module 2. Specifically, the housing 50 supports the substrate 10 of the light source module 2. The housing 50 also houses the substrate 10 and the heat sink 40.

[0054] As shown in FIGS. 2 and 3, the housing 50 has a bottom 51 and a side wall 52 standing upright from the bottom 51. The bottom 51 is annular. In the present embodiment, the bottom 51 is annular. The side wall 52 is cylindrical. In the present embodiment, the side wall 52 is cylindrical. Specifically, the side wall 52 is formed so that the opening diameter increases toward the translucent cover 80. As shown in FIGS. 3 and 8, the side wall 52 surrounds the light source module 2 and the heat sink 40.

[0055] As shown in FIG. 3 , the housing 50 further has a holder portion 53. The holder portion 53 holds the adapter 60. The holder portion 53 is cylindrical with an opening and is provided in the center of the housing 50. The holder portion 53 is an adapter guide and has a structure into which the adapter 60 is fitted. In this embodiment, the housing 50 is configured integrally with the holder portion 53.

[0056] The housing 50 is made of a resin material such as PBT (polybutylene terephthalate). Specifically, the housing 50 is a resin molded product made of an insulating resin material. Therefore, the bottom 51, the side wall 52, and the holder 53 are integrally formed. In other words, by making the housing 50 out of resin, the housing 50 can be integrated with the holder 53.

[0057] The housing 50 may be made of a metal material instead of a resin material. For example, the bottom 51 and the side wall 52 of the housing 50 may be formed by pressing a metal plate such as a steel plate or an aluminum plate. In this case, the holder 53 may be a separate part from the housing 50 and made of a resin material.

[0058] 3 and 8, the housing 50 that supports the substrate 10 is connected to the substrate 10. That is, the substrate 10 and the housing 50 are connected and fixed to each other. Specifically, a screw hole 50a is provided in the housing 50, and the substrate 10 and the housing 50 are fixed by screwing a second screw M2 inserted into a second through-hole 10b of the substrate 10 into the screw hole 50a of the housing 50.

[0059] In the present embodiment, the screw hole 50a is provided in the holder portion 53. Therefore, the board 10 is screwed and fixed to the holder portion 53 by the second screw M2. In addition, the connector 70 is interposed between the board 10 and the holder portion 53, and the second screw M2 is inserted through the second through-hole 10b of the board 10 and the through-hole 70a of the connector 70 and screwed into the screw hole 50a of the housing 50. Therefore, the board 10, the connector 70, and the housing 50 are fastened together and fixed by the second screw M2.

[0060] 2, the second through-hole 10b of the substrate 10 and the through-hole 70a of the connector 70 are provided at positions corresponding to the screw holes 50a of the housing 50. In other words, in a plan view, the second through-hole 10b of the substrate 10 and the through-hole 70a of the connector 70 are provided at positions that overlap the screw holes 50a of the housing 50.

[0061] In this way, the housing 50 is connected to the board 10 but is not connected to the heat sink 40. In other words, the housing 50 and the heat sink 40 are not connected to each other and are independent of each other. In this embodiment, the heat sink 40 is connected only to the board 10 and is supported by the board 10 fixed to the housing 50. In this way, the heat sink 40 is indirectly supported by the housing 50 by being fixed to the board 10. Furthermore, as shown in FIG. 3 , the heat sink 40 is arranged so that there is a space between the board 10 and the bottom 51 of the housing 50.

[0062] 3 and 8, the cylindrical portion 42 of the heat sink 40 and the side wall portion 52 of the housing 50 are not in contact with each other, and a gap exists between the side surface of the cylindrical portion 42 of the heat sink 40 and the side wall portion 52 of the housing 50. Note that the side surface of the cylindrical portion 42 of the heat sink 40 and the side wall portion 52 of the housing 50 are close to each other.

[0063] The open end of the tubular portion 42 of the heat sink 40 is open. Specifically, the open end of the tubular portion 42 of the heat sink 40 and the bottom 51 of the housing 50 are not in contact with each other, and a gap exists between the open end of the tubular portion 42 of the heat sink 40 and the bottom 51 of the housing 50. The tubular portion 42 of the heat sink 40 extends toward the bottom 51 of the housing 50, and the open end of the tubular portion 42 and the bottom 51 are close to each other.

[0064] As shown in FIG. 1 , the adapter 60 is an attachment member for attaching the lighting device 1 to the hooking ceiling body 110. The adapter 60 is detachably attached to the hooking ceiling body 110. The adapter 60 has a substantially cylindrical housing made of an insulating resin material such as PBT and a pair of L-shaped metal fittings for hooking onto holes in the hooking ceiling body 110. The pair of metal fittings of the adapter 60 function to mechanically and electrically connect the hooking ceiling body 110 and the lighting device 1. Specifically, the pair of metal fittings of the adapter 60 are hooked onto a pair of holes in the hooking ceiling body 110, thereby electrically connecting them to the metal terminals of the hooking ceiling body 110. In this way, by connecting the adapter 60 to the hooking ceiling body 110, AC power from the hooking ceiling body 110 is supplied to the metal fittings of the adapter 60. When the lighting device 1 is installed on the ceiling 100, the adapter 60 is stored in the holder portion 53 of the housing 50.

[0065] As shown in FIG. 3, the adapter 60 stored in the holder portion 53 of the housing 50 is electrically connected to a connector 70 fixed to the housing 50. The connector 70 is a resin molded product into which a pair of metal terminals 71 are insert-molded. The connector 70 is provided so as to cover the holder portion 53 of the housing 50. The pair of metal terminals 71 of the connector 70 are electrically connected to wiring formed on the board 10. As a result, AC power from the hook ceiling body 110 is supplied to the multiple circuit elements 30 that constitute the power supply circuit via the pair of metal fittings of the adapter 60 and the pair of connectors 70 and the wiring formed on the board 10.

[0066] 3, the light-transmitting cover 80 is a globe that covers the light source 20. The light-transmitting cover 80 is also an outer cover that constitutes an outer member of the lighting device 1. The light-transmitting cover 80 is translucent and transmits light emitted from the light source 20. In other words, the light from the light source 20 that enters the inner surface of the light-transmitting cover 80 passes through the light-transmitting cover 80 and is extracted to the outside of the light-transmitting cover 80.

[0067] The light-transmitting cover 80 can be made of a light-transmitting resin material, such as polycarbonate, acrylic, polyethylene terephthalate, or polyvinyl chloride.

[0068] In the present embodiment, the light-transmitting cover 80 has light diffusibility. By providing the light-transmitting cover 80 with light diffusibility, the light from the light source 20 that enters the light-transmitting cover 80 can be diffused (scattered), and therefore the light can be extracted uniformly from the entire light-transmitting cover 80.

[0069] In this case, for example, the light-transmitting cover 80 can be made milky white to have light diffusibility. Specifically, the light-transmitting cover 80 can be made light diffusible by forming the light-transmitting cover 80 from a resin material in which light-diffusing particles are dispersed. The light-transmitting cover 80 may also be made light diffusible by forming a milky white light-diffusing film on the inner or outer surface of the light-transmitting cover 80. Alternatively, the light-diffusing property may be imparted to the transparent light-transmitting cover 80 by forming a plurality of light-diffusing dots or a plurality of minute asperities (grain) on the surface of the transparent light-transmitting cover 80. The light-diffusing property may also be imparted to the milky white light-transmitting cover 80 by further forming a plurality of light-diffusing dots or a plurality of minute asperities.

[0070] The light-transmitting cover 80 covers the entire housing 50. Therefore, the shape of the light-transmitting cover 80 corresponds to the shape of the housing 50. In this embodiment, since the housing 50 is circular, the light-transmitting cover 80 has a circular dome shape. Note that if the housing 50 is square, the light-transmitting cover 80 has a rectangular dome shape.

[0071] As shown in FIG. 3 , the light-transmitting cover 80 is fixed to the housing 50 by silicone resin 90. That is, the light-transmitting cover 80 is fixed to the housing 50 when the lighting device 1 is shipped and is configured so as not to be detachable from the housing 50. Therefore, when installing the lighting device 1 on the ceiling 100, the lighting device 1 is connected to a hooking ceiling body 110 (power supply unit) installed on the ceiling 100 with the light-transmitting cover 80 attached to the housing 50. Specifically, by attaching an adapter 60 to the hooking ceiling body 110 and mounting the holder part 53 of the housing 50 of the lighting device 1 to the adapter 60, the lighting device 1 can be electrically and mechanically connected to the hooking ceiling body 110. In this way, by connecting the lighting device 1 with the light-transmitting cover 80 attached to the housing 50 to the adapter 60 installed on the hooking ceiling body 110, the lighting device 1 can be easily installed on the ceiling 100.

[0072] In the present embodiment, the light-transmitting cover 80 is fixed to the housing 50, but this is not limiting. For example, the light-transmitting cover 80 may be attached to the housing 50 in a detachable manner.

[0073] Here, the features of the lighting device 1 according to the embodiment will be described, including the background to the invention. Specifically, the description will be made in comparison with a lighting device 1X of a comparative example, with reference to Fig. 9. Fig. 9 is a cross-sectional view of the lighting device 1X of the comparative example.

[0074] 9, the lighting device 1X of the comparative example includes a metal housing 50X that is the fixture body, a board 10 attached to the housing 50X, a plurality of light sources 20 mounted on the board 10, an adapter 60 connected to a hook ceiling body, a connector 70 positioned between the adapter 60 and the board 10, a light-transmitting cover 80 that covers the plurality of light sources 20, and a resin holder 53X that holds the adapter 60. The external size of the lighting device 1X of the comparative example is φ330 mm.

[0075] In the lighting device 1X of the comparative example, the substrate 10 is fixed to each of the housing 50X and the holder 53X. Specifically, the substrate 10 is directly connected to the housing 50X and fixed to the housing 50X with a first screw M1. Furthermore, the substrate 10 is fixed to a holder 53X supported by the housing 50X with a second screw M2. Specifically, the substrate 10 and the holder 53X, together with a connector 70 between the substrate 10 and the holder 53X, are fixed together with the second screw M2.

[0076] Thus, in the lighting device 1X of the comparative example, the substrate 10 is fixed to the holder 53X supported by the housing 50X with the second screw M2, and is further fixed at another location on the housing 50X with the first screw M1. With this structure, the substrate 10 can be supported by the housing 50X, and heat generated by the light source 20 mounted on the substrate 10 can be conducted to the metal housing 50X and dissipated.

[0077] However, in the lighting device 1X of the comparative example having such a structure, stress is applied to the substrate 10 due to the stacking tolerance between the substrate 10, the housing 50X, and the holder 53X, causing distortion and warping of the substrate 10. As a result, there is a risk of problems such as damage to the light source 20 mounted on the substrate 10. Furthermore, if a circuit element 30 is also mounted on the substrate 10, there is a risk that the circuit element 30 will also be damaged due to distortion occurring in the substrate 10.

[0078] In particular, when the lighting device 1X is miniaturized so that the external size of the lighting device 1X is φ300 mm or less, the distance between the screws (the distance between the first screw M1 and the second screw M2, and the distance between the first screws M1) becomes shorter, and the stress applied to the substrate 10 increases due to the stack-up tolerance between the substrate 10, the housing 50X, and the holder 53X.

[0079] Therefore, it is conceivable to configure the substrate 10 and the housing 50X so that they are not directly connected. However, such a configuration would prevent the heat generated by the light source 20 from being conducted to the metal housing 50 via the substrate 10. This would result in a decrease in the heat dissipation performance of the heat generated by the light source 20. Since the light source 20's luminous efficiency and light output decrease due to heat generated by the light source 20, a decrease in the heat dissipation performance of the heat generated by the light source 20 would result in a decrease in the total luminous flux of the lighting device 1X. Furthermore, even if the lighting device 1X is made smaller, the mounting density of the multiple light sources 20 increases, which decreases the heat dissipation performance of the heat generated by the light source 20. Therefore, it is conceivable to reduce the number of mounted light sources 20 so as not to reduce the heat dissipation performance of the heat generated by each light source 20. However, doing so would result in a decrease in the total luminous flux of the lighting device 1X.

[0080] As a result of intensive research into these issues, the inventors of the present application have discovered an illumination device that can suppress the stress on the substrate while suppressing a decrease in total luminous flux even when the illumination device is made smaller.

[0081] Specifically, the lighting device 1 according to this embodiment includes a substrate 10, a plurality of light sources 20 arranged on a first surface 11 of the substrate 10, a heat sink 40 located on a second surface 12 side of the substrate 10, and a housing 50 that houses the substrate 10 and the heat sink 40, the substrate 10 and the housing 50 being connected to each other, the substrate 10 and the heat sink 40 being connected to each other, and the housing 50 and the heat sink 40 being independent of each other without being connected to each other. In other words, in the lighting device 1 according to this embodiment, the substrate 10 is connected to the housing 50, and is also connected to the heat sink 40 that is not connected to the housing 50.

[0082] This configuration can prevent stress from being applied to the substrate 10 due to stacking tolerances between the substrate 10, the housing 50X, and the holder 53X, as in the comparative lighting device 1X shown in FIG. 9 . Furthermore, in this embodiment, the substrate 10 is not directly connected to (i.e., not in contact with) the housing 50. However, compared to the lighting device 1X of the comparative example, a heat sink 40 directly connected to the substrate 10 is newly added. Therefore, even if the substrate 10 is not directly connected to the housing 50, the heat generated by the light source 20 arranged on the substrate 10 can be efficiently dissipated by the heat sink 40. This can also prevent a decrease in the light output of the light source 20 and a decrease in the total luminous flux of the lighting device 1. Moreover, because the heat sink 40 and the housing 50 are not connected to each other and are independent of each other, there is no stacking tolerance due to the added heat sink 40, and therefore the heat sink 40 does not apply stress to the substrate 10.

[0083] As described above, the lighting device 1 according to this embodiment can reduce the stacking tolerance of parts while maintaining or improving the heat dissipation performance of heat generated by the light source 20 compared to the lighting device 1X of the comparative example shown in Fig. 9. In particular, the structure of the lighting device 1 according to this embodiment eliminates the need to consider the stacking tolerance.

[0084] As described above, the lighting device 1 according to the present embodiment can suppress the stress on the substrate 10 while suppressing a decrease in the total luminous flux of the lighting device 1. In particular, even if the lighting device 1 is made smaller, the stress on the substrate 10 can be suppressed while suppressing a decrease in the total luminous flux.

[0085] Furthermore, in the lighting device 1 according to this embodiment, the heat sink 40 has a plate portion 41 located between the housing 50 and the substrate 10, and a tubular portion 42 extending from the outer peripheral end of the plate portion 41 to the side opposite the substrate 10.

[0086] With this configuration, heat generated by the light source 20 arranged on the substrate 10 can be conducted to the plate portion 41 and then to the cylindrical portion 42. This allows the heat generated by the light source 20 arranged on the substrate 10 to be dissipated more efficiently.

[0087] Furthermore, in the lighting device 1X of the comparative example shown in FIG. 9, the holder 53X that holds the adapter 60 is a separate part from the housing 50X, but in the lighting device 1 of the present embodiment, the housing 50 is integrally formed with the holder portion 53 that holds the adapter 60.

[0088] This configuration can eliminate the stacking tolerance caused by the holder 53X that occurs in the lighting device 1X of the comparative example. That is, in the lighting device 1X of the comparative example, the holder 53X is a separate part from the housing 50X, and therefore stress is applied to the substrate 10 due to the stacking tolerance caused by the holder 53X and the housing 50X. In contrast, in the present embodiment, the housing 50 is configured integrally with the holder portion 53, and therefore there is no stacking tolerance caused by the housing 50 and the holder portion 53. As a result, stress is not applied to the substrate 10 due to the stacking tolerance caused by the housing 50 and the holder portion 53.

[0089] Furthermore, in the illumination device 1X of the comparative example shown in FIG. 9, the housing 50X is made of metal, and the substrate 10 is brought into contact with the housing 50X to dissipate heat generated by the light source 20. However, in the illumination device 1 according to the present embodiment, the heat generated by the light source 20 is dissipated by providing a heat sink 40. This eliminates the need to make the housing 50 out of metal, and the housing 50 can be made of a resin material. This improves the degree of freedom in the shape of the housing 50, and makes it possible to easily integrate the housing 50 with the holder portion 53. Furthermore, by making the housing 50 out of a resin material, costs can be reduced.

[0090] (Variation) Although the lighting device according to the present invention has been described above based on the embodiment, the present invention is not limited to the above embodiment.

[0091] For example, in the above embodiment, the lighting device 1 may be configured to be able to control the brightness and color of the light emitted from the plurality of light sources 20.

[0092] In the above embodiment, the light source 20 is an SMD-type LED element, but this is not limiting. For example, the light source 20 may be a COB (Chip On Board) type light source module in which an LED chip (bare chip) itself is used as the light source 20 and the LED chip is directly mounted (primarily mounted) on the substrate 10. In this case, the multiple LED chips mounted on the substrate 10 may be collectively or individually sealed with a sealing member. Furthermore, the sealing member may contain a wavelength conversion material such as a yellow phosphor as described above.

[0093] In the above embodiment, the light source 20 is a BY-type white LED light source that emits white light using a blue LED chip and a yellow phosphor. However, this is not limiting. For example, a phosphor-containing resin containing red and green phosphors may be used in combination with a blue LED chip to emit white light. Furthermore, in order to improve color rendering, red and green phosphors may be mixed in addition to the yellow phosphor. LED chips that emit colors other than blue may also be used. For example, a UV LED chip that emits ultraviolet light with a shorter wavelength than the blue light emitted by a blue LED chip may be used, and white light may be emitted using blue, green, and red phosphors that are excited primarily by the ultraviolet light to emit blue, red, and green light.

[0094] In the above embodiment, the light source 20 is configured by an LED, but is not limited to this. Specifically, the light source 20 may be configured by other solid-state light-emitting elements such as a semiconductor laser, an organic EL (Electro Luminescence), or an inorganic EL.

[0095] Furthermore, in the above embodiment, the light source module 2 is an integrated power supply module in which not only the light source 20 but also the circuit elements 30 constituting the power supply circuit are mounted on the substrate 10, but this is not limiting. Specifically, the circuit elements 30 constituting the power supply circuit may be mounted on a circuit board provided separately from the substrate 10. In other words, a circuit module including the circuit board and the circuit elements 30 may be provided separately. In this case, the substrate 10 may be a single-sided wiring board in which wiring is formed only on the first surface 11.

[0096] In the above embodiment, the lighting device 1 is a small lighting fixture with an outer size of φ300 mm or less, but this is not limiting. Specifically, the lighting device 1 may be a lighting fixture with an outer size of φ300 mm or more.

[0097] In the above embodiment, the lighting device 1 is a ceiling light, but this is not limiting. Specifically, the lighting device 1 may be a lighting fixture other than a ceiling light. For example, the lighting device 1 may be a lighting fixture such as a downlight.

[0098] In addition, the present disclosure also includes embodiments obtained by various modifications of the above-described embodiments that would occur to a person skilled in the art, and embodiments realized by arbitrarily combining the components and functions of the embodiments within the scope of the present invention. Furthermore, the present invention also includes any combination of two or more claims from among the multiple claims set forth in the claims at the time of filing, provided that there is no technical contradiction. For example, when a dependent claim set forth in the claims at the time of filing is made into a multiple claim or multiple multiple claims that cite all of the superordinate claims within the scope of the technical contradiction, the present invention also includes all combinations of claims included in that multiple claim or multiple multiple multiple claims. [Explanation of symbols]

[0099] 1. Lighting equipment 10 Substrate 11 Page 1 12 Side 2 20 light source 20a 1st light source 20b 2nd light source 30 Circuit Elements 40 Heatsink 41 Board part 42 Cylinder part 50 cabinets 53 Holder part 60 adapter 80 Translucent cover

Claims

1. a substrate having a first surface and a second surface opposite the first surface; a plurality of light sources disposed on the first surface of the substrate; a heat sink located on the second surface side of the substrate; a housing that houses the substrate and the heat sink, the substrate and the housing are connected to each other, the substrate and the heat sink are connected to each other; The housing and the heat sink are independent of each other without being connected to each other. Lighting equipment.

2. The housing is integrally formed with a holder portion for holding an adapter connected to a power supply portion installed in the building material. The lighting device according to claim 1 .

3. The housing is made of a resin material.

3. The lighting device according to claim 2.

4. The adapter is provided The adapter is housed in the holder portion.

3. The lighting device according to claim 2.

5. The heat sink includes a plate portion located between the housing and the substrate; a cylindrical portion extending from an outer peripheral end of the plate portion to a side opposite to the substrate side, The lighting device according to any one of claims 2 to 4.

6. the plate portion has a ring-shaped planar shape having an opening at a position overlapping the holder portion, The planar shape of the substrate is not annular.

6. The lighting device according to claim 5.

7. When viewed from above, the plurality of light sources are arranged at positions overlapping the plate portion.

7. The lighting device according to claim 6.

8. a plurality of circuit elements constituting a power supply circuit for supplying power to the light source; the plurality of circuit elements are disposed on the substrate; The lighting device according to any one of claims 1 to 4.

9. the plurality of circuit elements are arranged in a ring shape on the substrate; the plurality of light sources are arranged on the inner circumferential side and the outer circumferential side of the plurality of circuit elements arranged in an annular manner; 9. The lighting device according to claim 8.

10. The first surface is a first region that is an inner circumferential region of the plurality of circuit elements that are annularly arranged, and that is a region in which a plurality of first light sources that are some of the plurality of light sources are arranged; a second region that surrounds the first region and in which the plurality of circuit elements are arranged in a circular pattern; a third region that surrounds the second region and in which a plurality of second light sources that are another part of the plurality of light sources are arranged in an annular shape; 10. The lighting device according to claim 9.

11. The pitch of the plurality of first light sources is greater than the pitch of the plurality of second light sources.

11. The lighting device according to claim 10.

12. a surface-mounted circuit element among the plurality of circuit elements and the plurality of light sources are mounted on the first surface; a circuit element with a lead among the plurality of circuit elements is mounted on the second surface; 10. The lighting device according to claim 9.

13. a light-transmitting cover for covering the light source; The lighting device is connected to a power supply unit installed in a building material with the light-transmitting cover attached to the housing. The lighting device according to any one of claims 1 to 4.

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