JP2020198159A - Illumination device - Google Patents

Abstract

To provide an illumination device capable of efficiently emitting illumination light that flickers less.SOLUTION: An illumination device 1 includes a light source 200 and a lighting circuit 100 causing the light source 200 to emit light. The lighting circuit 100 includes a rectifying circuit 120 that rectifies AC voltage input to a pair of input terminals 121a and 121b, and outputs pulse voltage from the pair of output terminals 122a and 122b, and a power storage element C that is electrically connected in series with the light source 200 between the pair of output terminals 122a and 122b and is charged or discharged based on pulse voltage. The light source 200 includes a serial connection part 210 including a plurality of light-emitting elements 22 electrically connected in series with each other. The number of serial connections of the light-emitting elements 22 in the serial connection part 210 is the number where the total of the forward voltage of the light-emitting elements 22 in the serial connection part 210 is 40% or more and 60% or less of the AC voltage. The serial connection part 210 emits light on the basis of the pulse voltage and the voltage charging the power storage element C.SELECTED DRAWING: Figure 4

Description

The present invention relates to a lighting device.

Semiconductor light emitting devices such as light emitting diodes (LEDs: Light Emitting Diodes) are widely used as light sources for various devices because of their small size, high efficiency, and long life. For example, LEDs are used as a light source for lighting such as lamps or lighting fixtures, or as a backlight source for liquid crystal display devices. For example, Patent Document 1 discloses an LED module including a substrate, a plurality of LEDs mounted on the substrate, and circuit elements mounted on the substrate.

JP-A-2018-92811

In a lighting device, there is a demand for a lighting device that can suppress power loss due to heat generation and efficiently emit illumination light. Further, it is desired that the flicker of the illumination light is small.

Therefore, an object of the present invention is to provide a lighting device capable of efficiently emitting illumination light in which flicker is suppressed.

In order to achieve the above object, the lighting device according to one aspect of the present invention includes a light source and a lighting circuit for emitting the light source, and the lighting circuit has a pair of input terminals and a pair of output terminals. An AC voltage input to the pair of input terminals is rectified, and a rectifying circuit that outputs a pulsating voltage from the pair of output terminals is electrically connected in series with the light source between the pair of output terminals. The light source includes a series connection portion including a plurality of light emitting elements electrically connected in series to each other, and includes a storage element that is charged and discharged based on a pulsating voltage, and is included in the series connection portion. The number of light emitting elements in series is a number such that the voltage drop due to the series connection portion is 40% or more and 60% or less of the AC voltage, and the series connection portion is charged with the pulsating voltage and the power storage element. It emits light based on the voltage.

According to the present invention, it is possible to provide a lighting device capable of efficiently emitting illumination light in which flicker is suppressed.

FIG. 1 is an external perspective view of the lighting device according to the embodiment. FIG. 2 is an exploded perspective view of the lighting device according to the embodiment. FIG. 3 is a cross-sectional view of the lighting device according to the embodiment. FIG. 4 is a circuit diagram of a lighting circuit and a light source of the lighting device according to the embodiment. FIG. 5 is a diagram showing a voltage waveform and a current waveform when the lighting device according to the embodiment is lit. FIG. 6 is a circuit diagram for explaining the current flow in the mode M0 of the lighting device according to the embodiment. FIG. 7 is a circuit diagram for explaining the current flow in the mode M1 of the lighting device according to the embodiment. FIG. 8 is a circuit diagram for explaining the current flow in the mode M2 of the lighting device according to the embodiment. FIG. 9 is a circuit diagram for explaining the current flow in the mode M3 of the lighting device according to the embodiment. FIG. 10 is a schematic diagram for explaining a substrate on which each of the lighting circuit and the light source of the lighting device according to the embodiment is arranged. FIG. 11 is a diagram for explaining the amount and efficiency of flicker with respect to the voltage ratio of the lighting device according to the embodiment. FIG. 12 is a circuit diagram of a lighting circuit and a light source of the lighting device according to the modified example of the embodiment. FIG. 13 is a schematic diagram for explaining a substrate on which each of the lighting circuit and the light source of the lighting device according to the modified example of the embodiment is arranged.

Hereinafter, the lighting device according to the embodiment of the present invention will be described in detail with reference to the drawings. In addition, all the embodiments described below show a specific example of the present invention. Therefore, the numerical values, shapes, materials, components, arrangement and connection forms of the components, steps, the order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present invention. Therefore, among the components in the following embodiments, the components not described in the independent claims will be described as arbitrary components.

Further, each figure is a schematic view and is not necessarily exactly illustrated. Therefore, for example, the scales and the like do not always match in each figure. Further, in each figure, substantially the same configuration is designated by the same reference numerals, and duplicate description will be omitted or simplified.

Further, in the present specification, terms indicating relationships between elements such as parallel or vertical, terms indicating the shape of elements such as circles or flat plates, and numerical ranges are not expressions expressing only strict meanings. , Is an expression meaning that a substantially equivalent range, for example, a difference of about several percent is included.

(Embodiment)
[Lighting device]
First, the configuration of the lighting device according to the present embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is an external perspective view of the lighting device 1 according to the present embodiment. FIG. 2 is an exploded perspective view of the lighting device 1 according to the present embodiment. FIG. 3 is a cross-sectional view of the lighting device 1 according to the present embodiment. Specifically, FIG. 3 shows a schematic cross-sectional structure when the illuminating device 1 is cut in a YZ plane passing through the central axis of the illuminating device 1 and viewed from the negative side of the X axis.

In this specification and each figure, the X-axis, the Y-axis, and the Z-axis indicate the three axes of the three-dimensional Cartesian coordinate system. The Z-axis direction is the vertical direction, and the direction perpendicular to the Z-axis (direction parallel to the XY plane) is the horizontal direction. The positive direction of the Z axis is vertically downward.

As shown in FIG. 1, the lighting device 1 is a ceiling light (down ceiling light) that is directly attached to the ceiling 2 without being embedded. The luminaire 1 is a luminaire with a built-in power supply circuit that emits light by AC power supplied through a power cable (not shown) drawn from the ceiling 2. The main emission direction of the light of the lighting device 1 is the side opposite to the ceiling 2 (the positive direction of the Z axis).

The diameter of the illuminating device 1 when viewed in a plan view (when viewed from the positive side of the Z axis) is in the range of about 120 mm or more and about 150 mm or less. The thickness of the illuminating device 1 (length in the Z-axis direction) is about 30 mm. Note that these dimensions are just an example.

As shown in FIG. 2, the lighting device 1 includes a housing 10, a light emitting module 20, a reflector 30, a light guide plate 40, a translucent cover 50, a lighting circuit module 60, a terminal block 70, and the like. A circuit case 80 and a mounting plate 90 are provided. The details of each component will be described below.

[Case]
The housing 10 is the main body of the lighting device 1, and is a housing that mainly houses the light emitting module 20, the lighting circuit module 60, and the like. The housing 10 is formed using, for example, a metal material such as aluminum. Specifically, the housing 10 is made of die-cast aluminum, but may be formed by pressing a sheet metal made of aluminum or the like.

As shown in FIGS. 2 and 3, the housing 10 includes a circular flat plate-shaped base portion 11 and a cylindrical first side wall portion 12 provided on the light-transmitting cover 50 side of the base portion 11. It has a cylindrical second side wall portion 13 provided on the mounting plate 90 side of the base portion 11.

The base portion 11 is a support base that supports the light emitting module 20 and the lighting circuit module 60. The base portion 11 also has a function of partitioning the storage space of the housing 10 into a space where the light emitting module 20 is provided and a space where the lighting circuit module 60 is provided. As shown in FIG. 3, the base portion 11 has a main surface 11a and a main surface 11b on the opposite side of the main surface 11a. The main surface 11a is a surface on the translucent cover 50 side, and is a surface on which the light emitting module 20 is placed. The main surface 11b is a surface on the mounting plate 90 side, and is a surface on which the lighting circuit module 60 is mounted. As shown in FIGS. 2 and 3, the base portion 11 is provided with a through hole 11c that penetrates the base portion 11 in the thickness direction (Z-axis direction) at the center.

The first side wall portion 12 is a cylindrical portion erected on the translucent cover 50 side along the outer circumference of the base portion 11. A translucent cover 50 is attached to the tip portion of the first side wall portion 12 in the vertical direction.

The second side wall portion 13 is a cylindrical portion erected on the mounting plate 90 side along the outer circumference of the base portion 11. As shown in FIG. 2, the second side wall portion 13 is provided with a screw hole 13a. By inserting the screw 94 (see FIG. 1) into the screw hole 13a and the screw hole 92a of the mounting plate 90, the second side wall portion 13 (housing 10) and the mounting plate 90 are fixed.

Although not shown, screws for fixing the light emitting module 20, the reflector 30, the light guide plate 40, the translucent cover 50, the lighting circuit module 60, the terminal block 70, the circuit case 80, and the like are attached to the housing 10. There is a screw hole into which the module is inserted, or a locking portion such as a claw or a recess.

[Light emitting module]
The light emitting module 20 is a light emitting unit of the lighting device 1 and includes a light source 200 (see FIG. 4). The light emitting module 20 emits white light, for example. The light emitting module 20 is supported by the base portion 11 of the housing 10. The light emitting module 20 is lit by an AC drive system (also referred to as an AC direct system).

As shown in FIGS. 2 and 3, the light emitting module 20 includes a light source substrate 21, a plurality of light emitting elements 22, and a connector terminal 23.

The light source substrate 21 is a circular flat plate-shaped member, and has a main surface 21a and a main surface 21b on the opposite side of the main surface 21a, as shown in FIG. Further, the light source substrate 21 is provided with a through hole 21c in the center that penetrates the light source substrate 21 in the thickness direction (Z-axis direction).

The main surface 21a is the main surface on the translucent cover 50 side, and a plurality of light emitting elements 22 and connector terminals 23 are mounted on the main surface 21a. All the mounting components provided on the main surface 21a, including the light emitting element 22 and the connector terminal 23, are surface mount type chip components (SMD: Surface Mount Device) that can be mounted by reflow solder.

The main surface 21b is in contact with the base portion 11 of the housing 10. Neither the light emitting element nor the circuit component is mounted on the main surface 21b. Further, since the component mounted on the main surface 21a does not include the lead component, the lead of the component mounted on the main surface 21a does not protrude from the main surface 21b. That is, the main surface 21b is not provided with the mounting component and a part thereof, and is in surface contact with the main surface 11a of the base portion 11.

The light source substrate 21 is a printed wiring board on which conductive wiring is formed. For example, a metal wiring having a predetermined shape is formed on the main surface 21a of the light source substrate 21. The plurality of light emitting elements 22 and the connector terminal 23 are solder-connected to the metal wiring, and are electrically connected by the metal wiring.

The light source substrate 21 includes, for example, a resin substrate made of an insulating resin material, a metal base substrate made of a metal material whose surface is coated with a resin, a ceramic substrate which is a sintered body of a ceramic material, or a glass substrate made of a glass material. Etc. can be used. The light source substrate 21 may have a multi-layer wiring structure. The light source substrate 21 is, for example, a circular flat plate, but is not limited to this. The light source substrate 21 is a rigid substrate, but may be a flexible substrate.

The plurality of light emitting elements 22 are included in the light source 200 (see FIG. 4) of the lighting device 1. Each of the plurality of light emitting elements 22 is, for example, an SMD type LED element that emits white light, and is mounted on the main surface 21a. The SMD type LED element includes a white resin package (container) having a recess, one or more LED chips primarily mounted on the bottom surface of the recess of the package, and a sealing member enclosed in the recess of the package. Have. The sealing member is formed by using a translucent resin material such as a silicone resin. The sealing member may be formed by using a phosphor-containing resin containing a wavelength conversion material such as a phosphor.

The LED chip is an example of a semiconductor light emitting element that emits light by a predetermined DC power, and as an example, is a bare chip that emits a single color of visible light. The LED chip is, for example, a blue LED chip that emits blue light, and has a peak wavelength in the range of, for example, 440 nm or more and 470 nm or less. In this case, since the light emitting element 22 emits white light, the sealing member contains a yellow phosphor such as YAG (yttrium aluminum garnet) that fluoresces the blue light from the blue LED chip as excitation light. To. That is, the light emitting element 22 emits white light obtained by mixing the blue light emitted from the blue LED chip and the yellow light emitted by the yellow phosphor excited by a part of the blue light.

As shown in FIG. 2, the plurality of light emitting elements 22 are provided side by side in an annular shape. The plurality of light emitting elements 22 may be provided concentrically in a plurality of rows.

The connector terminal 23 is a terminal for making an electrical connection with the lighting circuit module 60. As shown in FIG. 3, one ends of the lead wires 64a and 64b are connected to the connector terminal 23. Instead of the connector terminal 23, a metal film (land) to which one ends of the lead wires 64a and 64b are soldered may be provided on the main surface 21a.

[a reflector]
The reflector 30 is an example of a reflective member that reflects the light emitted from the light guide plate 40 toward the translucent cover 50. The reflector 30 is formed by using a material having a high light reflectance such as a highly reflective polycarbonate resin, a highly reflective nylon resin, a highly reflective polybutylene terephthalate resin, or a highly reflective foamed resin.

As shown in FIGS. 2 and 3, the reflector 30 has an outer peripheral portion 31 and a central portion 32. An opening 33 is provided between the outer peripheral portion 31 and the central portion 32 for exposing a plurality of light emitting elements 22 and arranging the incident portion 42 of the light guide plate 40.

The outer peripheral portion 31 is an annular portion on the outer side in the radial direction from the central portion 32. The outer peripheral portion 31 is located on the outer side in the radial direction with respect to the plurality of light emitting elements 22 arranged in an annular shape in a plan view. The outer peripheral portion 31 reflects the light emitted from the outer peripheral portion 41b of the light guide plate 40. The light reflected by the outer peripheral portion 31 is emitted through the light guide plate 40 (mainly the outer peripheral portion 41b) and the translucent cover 50. The outer peripheral portion 31 has a ring-shaped flat plate portion and a curved portion curved so as to approach the light source substrate 21 from the radial inner end portion of the flat plate portion toward the center of the lighting device 1. The shape of the outer peripheral portion 31 is a shape along the surface (the surface on the light source substrate 21 side) of the outer peripheral portion 41b of the light guide plate 40.

The central portion 32 is a disk-shaped portion located inward in the radial direction from the outer peripheral portion 31. The central portion 32 is located inside the plurality of light emitting elements 22 arranged in an annular shape in the radial direction in a plan view. The central portion 32 reflects the light emitted from the central portion 41a of the light guide plate 40. The light reflected by the central portion 32 is emitted through the light guide plate 40 (mainly the central portion 41a) and the translucent cover 50. The central portion 32 has a circular flat plate portion and a curved portion curved so as to approach the light source substrate 21 from the outer peripheral end portion of the flat plate portion toward the outside in the radial direction of the lighting device 1. The shape of the central portion 32 is a shape along the surface (the surface on the light source substrate 21 side) of the central portion 41a of the light guide plate 40.

The opening 33 is provided in an annular shape between the outer peripheral portion 31 and the central portion 32, for example. The opening 33 is provided so as to expose a plurality of light emitting elements 22.

The opening 33 is continuously provided over the entire circumference between the outer peripheral portion 31 and the central portion 32. That is, the outer peripheral portion 31 and the central portion 32 are separated. For example, a flange portion provided with a screw hole is provided at each of the central end portion of the outer peripheral portion 31 and the radial outer end portion of the central portion 32. By inserting a screw (not shown) into the screw hole, the reflector 30 is fixed to the base portion 11 of the housing 10.

Further, the opening 33 may be provided intermittently for each one or a plurality of light emitting elements 22. The outer peripheral portion 31 and the central portion 32 may be connected and integrally formed, for example. For example, a connecting portion for connecting the central end of the outer peripheral portion 31 and the radial outer end of the central portion 32 may be provided. The connecting portion is located between two adjacent light emitting elements 22 so as not to cover the light emitting element 22. For example, a screw hole is provided in the connection portion, and the reflector 30 is fixed to the base portion 11 of the housing 10 by inserting a screw (not shown) into the screw hole. The method of fixing the reflector 30 is not particularly limited.

[Light guide plate]
The light guide plate 40 is an optical member that guides light emitted by a plurality of light emitting elements 22. The light guide plate 40 is arranged so as to face the light source substrate 21. Specifically, the light guide plate 40 is arranged so as to face the light source substrate 21 with a reflector 30 interposed therebetween. The light guide plate 40 is formed by using, for example, a transparent resin material such as acrylic resin, polycarbonate resin, and polystyrene resin, or a translucent material such as glass.

As shown in FIGS. 2 and 3, the light guide plate 40 has an exit portion 41 and an incident portion 42. The light guide plate 40 guides the light emitted from the plurality of light emitting elements 22 and incident from the incident portion 42 to the emitting portion 41 by repeatedly totally reflecting the light inside, and emits the light from the surface of the emitting portion 41 on the translucent cover 50 side. Let me. The light emitting surface (the surface on the light transmitting cover 50 side) of the emitting unit 41 is parallel to the main surface 21a of the light source substrate 21.

The emitting portion 41 is a circular flat plate-shaped portion that is incident from the incident portion 42 and emits the light guided through the light guide plate 40. The emitting portion 41 has a central portion 41a and an outer peripheral portion 41b.

The central portion 41a is a circular flat plate-shaped portion located inward in the radial direction from the outer peripheral portion 41b. The central portion 41a has substantially the same size and substantially the same shape as the central portion 32 of the reflector 30 in a plan view.

The outer peripheral portion 41b is an annular portion on the outer side in the radial direction from the central portion 41a. The outer peripheral portion 41b has substantially the same size and substantially the same shape as the outer peripheral portion 31 of the reflector 30 in a plan view. A light extraction structure is provided on the surface of each of the central portion 41a and the outer peripheral portion 41b on the reflector 30 side. The light extraction structure is, for example, a plurality of minute irregularities (prisms), and by scattering the guided light, it is emitted from the surface of the light guide plate 40 on the light transmitting cover 50 side.

The incident portion 42 is a portion where light from a plurality of light emitting elements 22 is incident. The incident portion 42 is a protruding portion protruding from the emitting portion 41 toward the plurality of light emitting elements 22. The incident portion 42 is located on the optical axis of each of the plurality of light emitting elements 22.

The incident portion 42 is located inside the emitting portion 41 in a plan view. Specifically, the incident portion 42 is provided in an annular shape between the central portion 41a and the outer peripheral portion 41b. As shown in FIG. 3, the incident portion 42 projects toward the light emitting element 22 from each of the radial outer end portion of the central portion 41a and the radial inner end portion of the outer peripheral portion 41b. There is. The incident portion 42 is formed so as to extend from the end portion on the light emitting element 22 side while curving toward the translucent cover 50.

[Transparent cover]
The translucent cover 50 is a circular dome-shaped optical member that covers the light guide plate 40, the reflector 30, and the light emitting module 20. The translucent cover 50 is formed by using, for example, a transparent resin material such as a silicone resin, an acrylic resin, or a polycarbonate resin, or a translucent material such as glass.

The light-transmitting cover 50 has, for example, light diffusing (scattering) properties. The translucent cover 50 is formed by using a white resin containing a light diffusing material (fine particles) such as silica or calcium carbonate. Alternatively, the surface of the light-transmitting cover 50 may be provided with a light diffusion (scattering) structure such as minute irregularities formed by embossing or the like. The light-transmitting cover 50 diffuses and emits the light emitted from the light guide plate 40.

The translucent cover 50 is attached to the first side wall portion 12 of the housing 10. For example, the translucent cover 50 is provided with a claw or a recess, and is fixed to the housing 10 by being locked to the recess or the claw provided in the first side wall portion 12.

[Lighting circuit module]
The lighting circuit module 60 includes a lighting circuit 100 (see FIG. 4) that lights the light source 200 of the lighting device 1. As shown in FIGS. 2 and 3, the lighting circuit module 60 includes a circuit board 61, a plurality of circuit components 62, and a connector terminal 63.

The circuit board 61 is a flat plate-shaped member, and has a main surface 61a and a main surface 61b on the opposite side of the main surface 61b. Further, the circuit board 61 is provided with a notch-shaped through hole 61c that penetrates the circuit board 61 in the thickness direction (Z-axis direction).

The main surface 61a is an example of the first main surface, and is the main surface on the mounting plate 90 side. As shown in FIGS. 2 and 3, a plurality of circuit components 62 and connector terminals 63 are mounted on the main surface 61a. All the mounting components provided on the main surface 61a, including the plurality of circuit components 62 and the connector terminals 63, are surface mount type chip components that can be mounted by reflow solder.

The main surface 61b is an example of the second main surface, and is in contact with the base portion 11 of the housing 10. The circuit component 62 is not provided on the main surface 61b. Specifically, the chip component is not mounted on the main surface 61b. Further, since the component mounted on the main surface 61b does not include the lead component, the lead of the component mounted on the main surface 61a does not protrude from the main surface 61b. That is, the main surface 61b is not provided with a mounting component or a part thereof, and is in surface contact with the main surface 11b of the base portion 11.

The circuit board 61 and the light source board 21 are arranged so that their mounting surfaces (main surfaces 61a and 21a) do not face each other. Specifically, the main surface 61b, which is not the mounting surface of the circuit board 61, and the main surface 21b, which is not the mounting surface of the light source board 21, are arranged so as to face each other via the base portion 11.

The circuit board 61 is a printed wiring board on which conductive wiring is formed. For example, a metal wiring having a predetermined shape is formed on the main surface 61a of the circuit board 61. The plurality of circuit components 62 and the connector terminal 63 are solder-connected to the metal wiring, and are electrically connected by the metal wiring.

The circuit board 61 includes, for example, a resin substrate made of an insulating resin material, a metal base substrate made of a metal material whose surface is coated with a resin, a ceramic substrate which is a sintered body of a ceramic material, or a glass substrate made of a glass material. Etc. can be used. The circuit board 61 may have a multi-layer wiring structure. The circuit board 61 is, for example, a fan-shaped flat plate having a central angle larger than 180 °, but is not limited thereto. The circuit board 61 is a rigid board, but may be a flexible board.

The plurality of circuit components 62 are electronic components that constitute the lighting circuit 100 shown in FIG. Specifically, the plurality of circuit components 62 include at least one of a resistance element such as a resistor, a diode, a transistor such as a control IC (Integrated Circuit), a FET (Field Effect Transistor), and a capacitive element. None of the plurality of circuit components 62 is a transformer element. That is, the lighting circuit 100 does not include a transformer element. The specific configuration of the lighting circuit 100 will be described later.

The connector terminal 63 is a terminal for making an electrical connection with the light emitting module 20. The other ends of the lead wires 64a and 64b shown in FIG. 3 are connected to the connector terminal 63. Instead of the connector terminal 63, a metal film (land) to which the other ends of the lead wires 64a and 64b are soldered may be provided on the main surface 61a.

The lead wires 64a and 64b are inserted through the through hole 61c of the circuit board 61, the through hole 11c of the base portion 11, and the through hole 21c of the light source substrate 21 to connect the connector terminal 63 and the connector terminal 23. As a result, the electric power generated by the lighting circuit 100 of the lighting circuit module 60 can be supplied to the plurality of light emitting elements 22 of the light emitting module 20 to cause the plurality of light emitting elements 22 to emit light.

[Terminal block]
The terminal block 70 is an example of a power receiving component that receives AC power from the outside. The terminal block 70 receives AC power by connecting the tip of a power cable (not shown) drawn from the ceiling 2. The terminal block 70 is electrically connected to the lighting circuit module 60. The AC power received by the terminal block 70 is supplied to the lighting circuit of the lighting circuit module 60.

The terminal block 70 is fixed to the housing 10 with screws (not shown), for example, but is not limited to this. The terminal block 70 and the lighting circuit module 60 may be integrated. For example, the terminal block 70 may be provided on the circuit board 61.

[Circuit case]
The circuit case 80 is a housing that protects the lighting circuit module 60. The circuit case 80 is a flat bottomed tubular housing having substantially the same shape as the plan view of the circuit board 61 of the lighting circuit module 60 in a plan view. The circuit case 80 is formed by using, for example, a polybutylene terephthalate resin.

The circuit case 80 is fixed to the housing 10 via screws (not shown). The method of fixing the circuit case 80 is not particularly limited.

[Mounting plate]
The mounting plate 90 is a member for mounting the housing 10 to the ceiling 2. The mounting plate 90 is formed using, for example, a metal material such as aluminum or iron. Specifically, the mounting plate 90 is formed by pressing a sheet metal.

As shown in FIG. 2, the mounting plate 90 has a circular main body portion 91 and an upright portion 92 erected on the outer periphery of the main body portion 91.

The main body 91 is provided with a through hole 91a in the center. A power cable (not shown) drawn from the ceiling 2 is inserted into the through hole 91a. The main body 91 is further provided with screw holes 91b. In the example shown in FIG. 2, two screw holes 91b are provided so as to face each other in the radial direction with the through hole 91a interposed therebetween. The mounting screws 93 shown in FIG. 3 are inserted into each of the two screw holes 91b.

Two standing portions 92 are provided at positions facing each other with the center of the main body portion 91 interposed therebetween. The upright portion 92 is provided with a screw hole 92a. The screw holes 92a are provided at positions that overlap with the screw holes 13a of the housing 10 when the mounting plate 90 and the housing 10 are combined. The screw 94 shown in FIG. 1 is inserted into the screw hole 92a.

When the lighting device 1 is attached to the ceiling 2, the attachment plate 90 is first fixed to the ceiling 2. Specifically, with the power cable (not shown) pulled out from the ceiling 2 passed through the through hole 91a and connected to the terminal block 70, the two mounting screws 93 are inserted into the screw holes 91b and the mounting plate 90 Is screwed to the ceiling 2. Further, the upright portion 92 of the mounting plate 90 fixed to the ceiling 2 so that the screw holes 13a of the housing 10 of the lighting device 1 in which the parts other than the mounting plate 90 are assembled and the screw holes 92a of the upright portion 92 overlap. Is inserted into the housing 10. The housing 10 is fixed to the mounting plate 90 by inserting the screws 94 into the overlapping screw holes 13a and 92a. As a result, the lighting device 1 is fixed to the ceiling 2.

[Circuit configuration]
Subsequently, the circuit configuration of the lighting circuit 100 of the lighting device 1 according to the present embodiment will be described with reference to FIG. FIG. 4 is a circuit diagram of the lighting circuit 100 and the light source 200 of the lighting device 1 according to the present embodiment.

The lighting circuit 100 causes the light source 200 to emit light by supplying AC power to the light source 200 from the AC power supply 110 shown in FIG. The AC power supply 110 is, for example, a general commercial power supply, and is an AC voltage source having an effective voltage of 100 V. The effective voltage value of the AC power supply 110 is not limited to 100V, and may be, for example, 90V or more and 250V or less.

The light source 200 emits light based on the pulsating voltage generated by the rectifier circuit 120 and the voltage charged in the power storage element C. As shown in FIG. 4, the light source 200 includes a first terminal 201, a second terminal 202, and a plurality of light emitting elements 22 electrically connected between the first terminal 201 and the second terminal 202. Have. The first terminal 201 is a terminal on the higher voltage side than the second terminal 202, and is electrically connected to the output terminal 122a of the rectifier circuit 120. The current I_LED flows from the first terminal 201 to the second terminal 202, so that the plurality of light emitting elements 22 emit light.

The light source 200 includes a series connection portion 210 including a plurality of light emitting elements 22 electrically connected in series with each other. The series connection unit 210 includes all of the light emitting elements 22 electrically connected in series among all the light emitting elements 22 provided on the main surface 21a. That is, all the light emitting elements 22 included in the series connection portion 210 are electrically connected in series. The series connection 210 is not provided with an electrical branch.

In this embodiment, only one series connection portion 210 is provided between the first terminal 201 and the second terminal 202. That is, all the light emitting elements 22 provided on the main surface 21a are electrically connected in series with each other to form one series connection portion 210. As an example, when the effective voltage value of the AC power supply 110 is 100V (that is, AC100V), the number of light emitting elements 22 included in one series connection unit 210 is 20, but is not limited to this. Further, when the effective voltage value of the AC power supply 110 is different from 100V in the range of 90V or more and 250V or less, the number of light emitting elements 22 can be adjusted proportionally with the number of 100V as a reference. Specifically, in the case of AC200V, the number of light emitting elements 22 can be 40, which is twice AC100V.

As shown in FIG. 4, the lighting circuit 100 includes a rectifier circuit 120 and a power storage element C. The lighting circuit 100 further includes a bleeder circuit 130, a current control circuit 140, a charging current control circuit 150, and rectifying elements D1 to D4. The lighting circuit 100 is a charge pump type power supply circuit.

The rectifier circuit 120 has a pair of input terminals 121a and 121b and a pair of output terminals 122a and 122b. The rectifier circuit 120 rectifies the AC voltage input to the pair of input terminals 121a and 121b (specifically, full-wave rectification), and outputs the pulsating voltage from the pair of output terminals 122a and 122b.

The pair of input terminals 121a and 121b are connected to both ends of the AC power supply 110.

The output terminal 122a is a terminal on the high potential side of the pulsating current voltage obtained by converting the AC voltage by the rectifier circuit 120. The output terminal 122a is connected to the anode of the rectifying element D4 and one end of the bleeder circuit 130.

The output terminal 122b is a terminal on the low potential side of the pulsating voltage obtained by converting the AC voltage by the rectifier circuit 120. The output terminal 122b is connected to the other end of the bleeder circuit 130. Further, the output terminal 122b is connected to the current control circuit 140, the charging current control circuit 150, and the anode of the rectifying element D3. Further, the output terminal 122b is grounded (grounded).

The bleeder circuit 130 supplies the input current Iin supplied from the AC power supply 110 to the light source 200 when the pulsating voltage is equal to or higher than a predetermined value (specifically, the second voltage V2 shown in FIG. 5). The bleeder circuit 130 does not supply the input current Iin supplied from the AC power supply 110 to the light source 200 when the pulsating voltage is less than the second voltage V2. When the pulsating voltage is less than the second voltage V2, the light source 200 emits light by supplying the discharge current Id from the power storage element C to the light source 200. Details will be described later.

The bleeder circuit 130 includes, for example, a series connection circuit of a resistor, a switching element, and a capacitor. The switching element is, for example, a transistor such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), but the switching element is not limited to this.

The current control circuit 140 is connected between the second terminal 202 and the output terminal 122b, and controls the current I_LED flowing through the light source 200. Specifically, the current control circuit 140 controls the current I_LED so that the current I_LED flowing through the light source 200 does not exceed a predetermined value. For example, the current control circuit 140 is a switch circuit that switches between conduction and non-conduction according to the magnitude of the pulsating voltage output from the rectifier circuit 120.

The current control circuit 140 includes, for example, switching elements and resistors connected in series. The current I_LED is controlled by controlling the conduction (on) and non-conduction (off) of the switching element.

The charging current control circuit 150 is a circuit that controls the charging current flowing through the power storage element C. The charging current control circuit 150 is electrically connected in series with the power storage element C between both ends of the current control circuit 140. Specifically, the rectifier element D1, the power storage element C, and the charging current control circuit 150 are connected in series in this order between the second terminal 202 of the light source 200 and the output terminal 122b of the rectifier circuit 120. There is. That is, the series connection circuit of the rectifying element D1, the power storage element C, and the charging current control circuit 150 is connected in parallel with the current control circuit 140. For example, the charging current control circuit 150 is a switch circuit that switches between conduction and non-conduction according to the magnitude of the pulsating voltage output from the rectifier circuit 120.

The charging current control circuit 150 includes, for example, switching elements and resistors connected in series. By controlling the on and off of the switching element, the charging current flowing through the power storage element C is controlled.

The power storage element C is a power storage element that is charged and discharged based on the pulsating voltage output by the rectifier circuit 120. The power storage element C is electrically connected in series with the light source 200 between the pair of output terminals 122a and 122b of the rectifier circuit 120. Specifically, the power storage element C is connected between the second terminal 202 of the light source 200 and the output terminal 122b of the rectifier circuit 120. More specifically, the cathode of the rectifying element D1 and the anode of the rectifying element D2 are connected to one end of the power storage element C. A charging current control circuit 150 and a cathode of the rectifying element D3 are connected to the other end of the power storage element C.

The power storage element C is a capacitor. Specifically, the power storage element C is a chip electrolytic capacitor mounted on the main surface 61a of the circuit board 61.

The rectifying elements D1 to D4 are rectifying elements for limiting the direction in which the current flows in one direction, respectively. The rectifying elements D1 to D4 are, for example, diodes, but are not limited thereto. The rectifying elements D1 to D4 may be diode-connected transistors.

The rectifying element D1 is an example of a first rectifying element that is connected between the second terminal 202 of the light source 200 and the power storage element C and causes a charging current Ic (see FIG. 9) to flow from the light source 200 toward the power storage element C. is there. The rectifying element D1 suppresses the flow of current from the power storage element C toward the second terminal 202 of the light source 200. The anode of the rectifying element D1 is connected to the second terminal 202 of the light source 200. The cathode of the rectifying element D1 is connected to one end of the power storage element C and the anode of the rectifying element D2.

The rectifying element D2 is a second rectifying element that is connected between the first terminal 201 of the light source 200 and the storage element C and causes a discharge current Id (see FIGS. 6 and 7) to flow from the storage element C toward the light source 200. This is an example. The rectifying element D2 suppresses the flow of current from the first terminal 201 of the light source 200 toward the power storage element C. As shown in FIG. 4, the rectifying element D2 is connected in parallel to the series connection circuit including the light source 200 and the rectifying element D1. The anode of the rectifying element D2 is connected to the cathode of the rectifying element D1 and one end of the power storage element C. The cathode of the rectifying element D2 is connected to the first terminal 201 of the light source 200 and the cathode of the rectifying element D4.

The rectifying element D3 is an example of a third rectifying element that is connected between the output terminal 122b of the rectifying circuit 120 and the power storage element C and allows the discharge current Id to flow by bypassing the charging current control circuit 150. The rectifying element D3 suppresses the flow of current from the power storage element C toward the output terminal 122b. The rectifying element D3 is connected in parallel to the charging current control circuit 150. The anode of the rectifying element D3 is connected to the output terminal 122b of the rectifying circuit 120 and the terminal on the output terminal 122b side of each of the bleeder circuit 130, the current control circuit 140 and the charging current control circuit 150. The cathode of the rectifying element D3 is connected to the other end of the power storage element C and the terminal on the power storage element C side of the charging current control circuit 150.

The rectifying element D4 is a fourth rectifying element that is connected between the output terminal 122a of the rectifying circuit 120 and the first terminal 201 of the light source 200, and causes an input current Iin (charging current Ic) to flow from the output terminal 122a toward the light source 200. This is an example. The rectifying element D4 suppresses the discharge current Id flowing from the power storage element C through the rectifying element D2 to flow toward the output terminal 122a and the bleeder circuit 130. The anode of the rectifying element D4 is connected to the output terminal 122a of the rectifying circuit 120 and one end (terminal on the output terminal 122a side) of the bleeder circuit 130. The cathode of the rectifying element D4 is connected to the cathode of the rectifying element D2 and the first terminal 201 of the light source 200.

[motion]
Subsequently, the operation of the lighting device 1 according to the present embodiment will be described with reference to FIGS. 5 to 9.

FIG. 5 is a diagram showing a voltage waveform and a current waveform when the lighting device 1 according to the present embodiment is lit. Specifically, FIG. 5A shows a time change of the output voltage V_BLK between the pair of output terminals 122a and 122b of the rectifier circuit 120. FIG. 5B shows the time change of the current Iin flowing from the AC power supply 110 to the input terminal 121a of the rectifier circuit 120. FIG. 5C shows the time change of the potential Vc of the terminal on the high potential side of the power storage element C (the connection point between the power storage element C and the rectifying elements D1 and D2). FIG. 5D shows the time change of the current I_LED flowing through the light source 200.

In this embodiment, the lighting circuit 100 has four modes M0 to M3. In the four modes M0 to M3, the paths of the currents flowing in the lighting circuit 100 are different from each other. The four modes M0 to M3 are switched based on the magnitude of the pulsating voltage (that is, the output voltage V_BLK).

As shown in FIG. 5A, a pulsating voltage (DC voltage) generated by full-wave rectification of the AC voltage by the rectifier circuit 120 between the pair of output terminals 122a and 122b of the rectifier circuit 120. ) Is output as the output voltage V_BLK. Since the output voltage V_BLK is the pulsating voltage, the mode of the lighting circuit 100 repeatedly changes in the order of modes M0, M1, M2, M3, M2, M1, and M0 according to the fluctuation of the output voltage V_BLK. By controlling the current control circuit 140 and the charging current control circuit 150 according to the mode change of the lighting circuit 100, a stable current I_LED flows through the light source 200 as shown in FIG. 5D. Since the magnitude of the current I_LED flowing through the light source 200 is constant, the amount of light emitted by the light source 200 is kept constant. Therefore, the lighting device 1 in which the change in the amount of light, that is, the flicker is suppressed is realized.

In the following, the four modes M0 to M3 of the lighting circuit 100 based on the magnitude of the pulsating voltage will be described with reference to FIGS. 5 to 9 with reference to FIGS. 6 to 9.

<Mode M0>
FIG. 6 is a circuit diagram for explaining the current flow in the mode M0 of the lighting device 1 according to the present embodiment. In FIG. 6, the path of the current flowing through the light source 200 is represented by a thick solid line polygonal arrow.

The mode M0 is a mode in which the output voltage V_BLK is less than the first voltage V1 as shown by FIG. 5A. The first voltage V1 is a voltage corresponding to the internal voltage Vcc of the bleeder circuit 130 (specifically, the voltage stored in the capacitor included in the bleeder circuit 130). The potential (output voltage V_BLK) of the output terminal 122a connected to the bleeder circuit 130 is less than the first voltage V1 and lower than the internal voltage Vcc. Therefore, as shown in FIG. 5B, the input current Iin does not flow.

In the mode M0, instead of the input current Iin, as shown in FIG. 6, the discharge current Id from the power storage element C flows through the light source 200, so that the light source 200 emits light. That is, the current I_LED flowing through the light source 200 is the discharge current Id. At this time, the current control circuit 140 is conductive, and the charging current control circuit 150 is non-conductive. As a result, the discharge current Id flows from the power storage element C through the rectifying element D2, the light source 200, the current control circuit 140, and the rectifying element D3 in this order. As shown in FIG. 5D, the current value of the current I_LED (discharge current Id) is constant at the current value If. At this time, since the power storage element C is discharged, the potential Vc at one end of the power storage element C gradually decreases as shown in FIG. 5C.

The first voltage V1 is a voltage corresponding to the internal voltage Vcc of the bleeder circuit 130, but "correspondence" here means, for example, proportional to the internal voltage Vcc. The proportionality coefficient is determined based on, for example, at least one of a plurality of circuit elements such as rectifying elements D1 to D4 included in the lighting circuit 100. The same applies to the second voltage V2 and the third voltage V3, which will be described later.

<Mode M1>
FIG. 7 is a circuit diagram for explaining the current flow in the mode M1 of the lighting device 1 according to the present embodiment. In FIG. 7, the path of the current flowing through the light source 200 is represented by a thick solid line polygonal arrow. Further, the path of the current flowing through the bleeder circuit 130 is represented by a thick broken line arrow. These are the same in FIGS. 8 and 9.

The mode M1 is a mode in which the output voltage V_BLK is equal to or more than the first voltage V1 and less than the second voltage V2, as shown in FIG. 5A. The second voltage V2 is a voltage that is larger than the first voltage V1 and corresponds to the forward voltage Vf of the light source 200. In the mode M1, the potential of the output terminal 122a (output voltage V_BLK) is less than the second voltage V2, which is lower than the forward voltage Vf of the light source 200. Therefore, as shown in FIG. 7, the input current Iin does not flow to the light source 200, but flows as a bleeder current Ib flowing through the bleeder circuit 130. As shown in FIG. 5B, the input current Iin is maintained at the current value I_BRD after reaching the current value I_BRD.

In the mode M1, as in the mode M0, as shown in FIG. 7, the discharge current Id from the power storage element C flows through the light source 200, so that the light source 200 emits light. At this time, the current control circuit 140 is conductive, and the charging current control circuit 150 is non-conductive. As a result, the discharge current Id flows from the power storage element C through the rectifying element D2, the light source 200, the current control circuit 140, and the rectifying element D3 in this order. Similar to mode M0, as shown in FIG. 5D, the current value of the current I_LED is constant at the current value If. Further, as shown in FIG. 5C, the potential Vc at one end of the power storage element C gradually decreases.

<Mode M2>
FIG. 8 is a circuit diagram for explaining the current flow in the mode M2 of the lighting device 1 according to the present embodiment.

The mode M2 is a mode in which the output voltage V_BLK is equal to or greater than the second voltage V2 and less than the third voltage V3, as shown by FIG. 5A. The third voltage V3 is a voltage that is larger than the second voltage V2 and corresponds to twice the forward voltage Vf of the light source 200. In the mode M2, since the output voltage V_BLK is equal to or higher than the second voltage V2, the input current Iin flows as the current I_LED flowing through the light source 200, as shown in FIG. At this time, the bleeder current Ib hardly flows. Therefore, the current value of the input current Iin is substantially equal to the current value of the current I_LED, and becomes constant at the current value If.

In the mode M2, the input current Iin from the output terminal 122a of the rectifier circuit 120 flows through the light source 200, so that the light source 200 emits light. At this time, the current control circuit 140 is conductive. As a result, the input current Iin flows from the output terminal 122a through the rectifier element D4, the light source 200, and the current control circuit 140 in this order. In the mode M2, neither the discharge current Id nor the charge current Ic from the power storage element C flows. Therefore, as shown in FIG. 5 (c), the potential Vc at one end of the power storage element C has a predetermined value Vc_L or Vc_H. It is kept constant.

<Mode M3>
FIG. 9 is a circuit diagram for explaining the current flow in the mode M3 of the lighting device 1 according to the present embodiment.

The mode M3 is a mode in which the output voltage V_BLK is equal to or higher than the third voltage V3. In the mode M3, since the output voltage V_BLK is equal to or higher than the third voltage V3, the input current Iin flows as the current I_LED flowing through the light source 200 and the charging current Ic flowing through the power storage element C, as shown in FIG. At this time, the bleeder current Ib hardly flows. Therefore, the current value of the input current Iin is substantially equal to the current value of the current I_LED and the current value of the charging current Ic, and becomes constant at the current value If.

In the mode M3, the input current Iin (charging current Ic) from the output terminal 122a of the rectifier circuit 120 flows through the light source 200 and the power storage element C, so that the light source 200 emits light and the power storage element C is charged. At this time, the current control circuit 140 is non-conducting, and the charging current control circuit 150 is conducting. As a result, the input current Iin (charging current Ic) flows from the output terminal 122a through the rectifying element D4, the light source 200, the rectifying element D1, the power storage element C, and the charging current control circuit 150 in this order. Since the charging current Ic flows through the power storage element C, the potential Vc at one end of the power storage element C gradually increases as shown in FIG. 5C.

The lighting circuit 100 may have a function of adjusting the amount of light emitted by the light source 200 within a predetermined range (so-called dimming function). For example, the lighting circuit 100 performs dimming by a phase control method. The lighting circuit 100 includes a switch for switching the output of the pulsating voltage (or AC voltage) and its stop according to the waveform of the AC voltage, and a control circuit (for example, a microcomputer) for controlling the on / off of the switch. The voltage values Vc_L and Vc_H charged in the power storage element C increase or decrease depending on the on / off ratio of the switch. Thereby, the magnitude of the current I_LED flowing through the light source 200 can be adjusted, and the amount of light emitted by the light source 200 can be adjusted.

[Board separated for light source and circuit]
Hereinafter, the effect of having the lighting device 1 according to the present embodiment having the substrates separated for the light source 200 and the lighting circuit 100 will be described.

FIG. 10 is a schematic diagram for explaining a substrate on which each of the lighting circuit 100 and the light source 200 of the lighting device 1 according to the present embodiment is arranged. In addition, in FIG. 10, each of the light source board 21 and the circuit board 61 is schematically represented by a frame of a broken line and a shade different from that of the broken line.

As shown in FIG. 10, the light source 200 including the plurality of light emitting elements 22 is provided on the light source substrate 21. While all the light emitting elements 22 included in the light source 200 are mounted on the light source substrate 21, none of the circuit components 62 constituting the lighting circuit 100 are mounted.

Further, all the circuit elements included in the lighting circuit 100 other than the plurality of light emitting elements 22 and the AC power supply 110 are mounted on the circuit board 61 as circuit components 62. Specifically, the circuit elements included in each of the rectifier circuit 120, the bleeder circuit 130, the current control circuit 140, and the charging current control circuit 150, and the power storage element C and the rectifier elements D1 to D4 are mounted on the circuit board 61. ing.

As shown in FIG. 10, the light source board 21 and the circuit board 61 are connected by two lead wires 64a and 64b. The lead wire 64a is an example of a first lead wire that connects the lighting circuit 100 and the first terminal 201 (see FIG. 4) of the light source 200. The lead wire 64b is an example of a second lead wire that connects the lighting circuit 100 and the second terminal 202 (see FIG. 4) of the light source 200.

Specifically, the lead wire 64a connects the terminal 63a provided on the circuit board 61 and the terminal 23a provided on the light source board 21. The terminal 23a is included in the connector terminal 23 and corresponds to the first terminal 201 of the light source 200. The terminal 63a is included in the connector terminal 63 and corresponds to a connection point between the cathode of the rectifying element D2 and the cathode of the rectifying element D4.

The lead wire 64b connects the terminal 63b provided on the circuit board 61 and the terminal 23b provided on the light source board 21. The terminal 23b is included in the connector terminal 23 and corresponds to the second terminal 202 of the light source 200. The terminal 63b is included in the connector terminal 63 and corresponds to a connection point between the anode of the rectifying element D1 and one end of the current control circuit 140 (the terminal on the light source 200 side).

As described above, the lighting device 1 according to the present embodiment includes two separated substrates, that is, a light source substrate 21 and a circuit substrate 61. The plurality of light emitting elements 22 included in the light source 200 are mounted on the light source board 21 and not mounted on the circuit board 61. The plurality of circuit elements constituting the lighting circuit 100 are mounted on the circuit board 61 as circuit components 62, and are not mounted on the light source board 21. In this way, the light source 200 and the lighting circuit 100 are separately configured on different substrates.

Since the light source board 21 for the light source 200 and the circuit board 61 for the lighting circuit 100 are separated, the circuit component 62 provided on the circuit board 61 emits light from the light emitting element 22 provided on the light source board 21. It is difficult to block. Therefore, even if the translucent cover 50 is brought closer to the light source 200 in order to reduce the thickness of the illumination device 1, shadows caused by the circuit components 62 are less likely to be generated on the translucent cover 50, so that the uniformity of the illumination light is increased. Can be done. As described above, according to the present embodiment, it is possible to realize a thin lighting device 1 having a high degree of uniformity of the illumination light.

Further, since the light source board 21 for the light source 200 and the circuit board 61 for the lighting circuit 100 are separated, the board area per board can be reduced. Therefore, by arranging the light source substrate 21 and the circuit board 61 so as to overlap each other in a plan view, the substrate area can be reduced and the lighting device 1 can be miniaturized.

Further, since the light source board 21 for the light source 200 and the circuit board 61 for the lighting circuit 100 are separated, the light source 200 and the lighting circuit 100 can be thermally separated. That is, it is possible to prevent the heat generated by each of the light source 200 and the lighting circuit 100 from affecting each other. As a result, for example, deterioration of the light emitting element 22 can be suppressed, and the life of the lighting device 1 can be extended.

Further, the electric connection between the light source 200 and the lighting circuit 100 can be easily performed by using the two lead wires 64a and 64b. At this time, since the number of lead wires may be two, the lead wires can be compactly organized in the housing 10.

Further, since the circuit component 62 is provided only on the main surface 61a of the circuit board 61, all the circuit components 62 can be mounted by the reflow process. Therefore, the large-sized solder tank required for the flow process is not required, and the size of the manufacturing equipment of the lighting device 1 can be suppressed.

Further, since the transformer element is usually a tall or large-sized component having a large area, the lighting device 1 can be made thinner or smaller by not providing the transformer element in the lighting circuit 100. ..

[Number of light emitting elements in series]
Subsequently, the number of light emitting elements 22 included in the light source 200 of the lighting device 1 according to the present embodiment will be described with reference to FIG.

FIG. 11 is a diagram for explaining the amount of flicker and the current efficiency with respect to the voltage ratio included in the light source 200 of the lighting device 1 according to the present embodiment. FIG. 11A shows the amount of fluctuation (amount of flicker) in the light output emitted by the light source 200 of the lighting device 1. FIG. 11B shows the current efficiency, which is the ratio of the current used for light emission of the light source 200 to the input current Iin input from the AC power supply 110.

In each of (a) and (b) of FIG. 11, the horizontal axis represents the voltage ratio. The voltage ratio is the ratio of the voltage drop due to the series connection portion 210 to the input voltage Vin. The input voltage Vin is an effective value of the AC voltage generated by the AC power supply 110, and is, for example, 100V.

In the present embodiment, the voltage drop by the series connection portion 210 is the forward voltage Vf. The forward voltage Vf is the sum of the forward voltages of the plurality of light emitting elements 22 included in the series connection portion 210. If a plurality of light emitting elements 22 have the same forward voltage V _F to each other, the forward voltage Vf is expressed by the number of series of one forward voltage V _F × emitting element 22.

As shown in FIG. 11A, when the voltage ratio is 0.55 or less, the light output fluctuation is 0%, and flicker is substantially not generated. When the voltage ratio exceeds 0.55 V, the larger the voltage ratio, the larger the light output fluctuation (absolute value). That is, the larger the voltage ratio, the larger the amount of flicker (flicker of light). For example, when the voltage ratio is 0.6, the output fluctuation is about −5%, and when the voltage ratio is 0.65, the output fluctuation is about −20%. When the output fluctuation (absolute value) is larger than 5%, the flicker of light becomes noticeable. Therefore, when the voltage ratio is 0.6 (= 60%) or less, flicker can be suppressed.

As shown in FIG. 11B, the current efficiency reaches its maximum value (about 70%) when the voltage ratio is about 0.6. The current efficiency is reduced when the voltage ratio is less than about 0.6 and when it is greater than about 0.6. When the voltage ratio is 0.55, the current efficiency is about 67%. When the voltage ratio is 0.5, the current efficiency is about 61%. When the voltage ratio is 0.4, the current efficiency is about 50%. When the current efficiency is less than 50%, the power consumption in the lighting circuit 100 other than the light emitting element 22 becomes large, and the heat generation amount of the lighting circuit 100 becomes large. Therefore, when the voltage ratio is 0.4 (= 40%) or more, the current efficiency can be improved. Since the amount of heat generated by the lighting circuit 100 is reduced by increasing the current efficiency, sufficient heat dissipation performance can be realized even if the housing 10 is made smaller or thinner.

From the above, when the voltage ratio is 0.4 or more and 0.6 or less, it is possible to suppress light flicker and improve the current efficiency. Further, when the voltage ratio is 0.5 or more and 0.55 or less, the output fluctuation of light can be reduced to 0%, that is, the flicker of light can be substantially eliminated while maintaining the current efficiency of 60% or more. When the voltage ratio is 0.55, the current efficiency can be maintained as high as about 67% in a state where there is substantially no light flicker. When the voltage ratio is larger than 0.55 and less than 0.6, the current efficiency can be further improved although the light flickers slightly.

When the input voltage Vin is 100V, the forward voltage Vf that satisfies the range of voltage efficiency of 0.4 or more and 0.6 or less is 40V or more and 60V or less. If one forward voltage _{V F} of the light emitting element 22 is about 2.75 V, the series number of the light emitting element 22 forward voltage Vf satisfies the 60V below the range of 40V is 14.5 (≒ 40V / 2 .75V) or more and 21.8 pieces (≈60V / 2.75V) or less, that is, 15 pieces or more and 21 pieces or less. When the voltage efficiency is 0.5 (Vf = 50V), the number of light emitting elements 22 in series is 18 (≈50V / 2.75V). When the voltage efficiency becomes 0.55 (Vf = 55V), the number of light emitting elements 22 in series is 20 (≈55V / 2.75V). That is, when the number of light emitting elements 22 in series is 20, the current efficiency can be maintained as high as about 67% in a state where there is substantially no light flicker.

When the number of series is 20, even if the input voltage Vin fluctuates from 100V, it is possible to suppress light flicker and maintain high current efficiency at the same time. For example, when the input voltages Vin are 90V, 100V and 110V, the voltage ratios are about 0.6, 0.55 and 0.5, respectively. As shown by the alternate long and short dash line in FIG. 11, the voltage ratio is in the range of 0.5 or more and about 0.6 or less. Therefore, when the number of series is 20, it is possible to suppress light flicker and maintain high current efficiency at the same time.

Also, a case forward voltage V _F of the light emitting element 22 is approximately 2.75V is described as an example, but not limited thereto. Forward voltage _{V F} of the light-emitting element 22, for example, may be 1.8V or 3.7V or less. For example, it is possible to forward voltage _{V F} is utilized 3.3V, the LED of 3.0V or 2.85V as the light emitting element 22. Depending on the magnitude of the forward voltage V _F, the appropriate scope of the series number that satisfies range voltage ratio is 0.4 or more and 0.6 or less is changed.

Further, the series connection unit 210 may include an impedance element such as a resistor, which is electrically connected in series to a plurality of light emitting elements 22. In this case, the voltage drop due to the series connection portion 210 is the sum of the forward voltage Vf and the voltage drop amount due to the impedance element. As a result, the number of light emitting elements 22 in series can be reduced while satisfying the range of voltage efficiency of 0.4 or more and 0.6 or less.

As described above, the lighting device 1 according to the present embodiment includes a light source 200 and a lighting circuit 100 that emits light from the light source 200. The lighting circuit 100 has a pair of input terminals 121a and 121b and a pair of output terminals 122a and 122b, rectifies the AC voltage input to the pair of input terminals 121a and 121b, and pulses from the pair of output terminals 122a and 122b. It has a rectifier circuit 120 that outputs a flow voltage, and a storage element C that is electrically connected in series with a light source 200 between a pair of output terminals 122a and 122b and is charged and discharged based on a pulsating voltage. The light source 200 includes a series connection portion 210 including a plurality of light emitting elements 22 electrically connected in series with each other. The number of light emitting elements 22 in series included in the series connection portion 210 is such that the voltage drop by the series connection portion 210 is 40% or more and 60% or less of the AC voltage. The series connection unit 210 emits light based on the pulsating current voltage and the voltage charged in the power storage element C.

As a result, the illumination light with suppressed flicker can be efficiently emitted.

Further, for example, voltage drop is the sum of the forward voltage V _F of the plurality of light emitting elements 22 included in the series-connected portion 210.

As a result, the number of light emitting elements 22 included in the series connection 210 can be increased as compared with the case where the series connection 210 includes impedance elements, so that the amount of illumination light can be increased. Therefore, the illumination light with suppressed flicker can be emitted more efficiently.

Further, for example, the light source 200 has a first terminal 201 electrically connected to the output terminal 122a and a second terminal 202. The series connection unit 210 is electrically connected between the first terminal 201 and the second terminal 202. The lighting circuit 100 is further connected between the second terminal 202 and the output terminal 122b, and is electrically connected to the power storage element C between both ends of the current control circuit 140 that controls the current flowing through the light source 200 and the current control circuit 140. The charging current control circuit 150, which is connected in series with the power storage element C and controls the charging current Ic flowing through the power storage element C, is connected between the second terminal 202 and the power storage element C, and is connected from the light source 200 toward the power storage element C. A rectifying element D1 that flows a charging current Ic, a rectifying element D2 that is connected between the first terminal 201 and a storage element C and flows a discharge current Id from the storage element C toward the light source 200, and an output terminal 122b and a storage element. It has a rectifying element D3 which is connected to C and allows a discharge current Id to flow by bypassing the charge current control circuit 150.

As a result, a constant current I_LED flows stably through the light source 200 by the AC direct method, so that the flicker of the light source 200 can be suppressed.

Further, for example, the series connection portion 210 is not provided with an electrical branch.

As a result, a current of the same magnitude flows through all the light emitting elements 22 included in the series connection portion 210. That is, it is possible to emit illumination light having a large amount of light by using all the light emitting elements 22. Further, since the current is not supplied only to the specific light emitting element 22, it is possible to prevent the life of the specific light emitting element 22 from being exhausted in advance. As a result, the life of the lighting device 1 can be extended.

Further, for example, the lighting device 1 further includes a light guide plate 40. The light guide plate 40 has an incident portion 42 in which the light from the light source 200 is incident, and a flat plate-shaped emitting portion 41 that emits the light incident from the incident portion 42. The incident portion 42 projects from the emitting portion 41 toward the light source 200, and is located inside the emitting portion 41 when the emitting portion 41 is viewed in a plan view.

As a result, since the light guide plate 40 is provided so as to spread from the light source 200 on both sides, the light emitted by the light source 200 can be expanded by the light source plate 40 and emitted from an exit surface larger than the light source 200. As a result, it is possible to realize a thin lighting device 1 having a high uniformity of illumination light.

[Modification example]
Here, a modified example of the lighting device 1 according to the embodiment will be described with reference to FIGS. 12 and 13.

FIG. 12 is a circuit diagram of the lighting circuit 101 and the light source 200 of the lighting device 1 according to this modification. FIG. 13 is a schematic diagram for explaining a substrate on which each of the lighting circuit 101 and the light source 200 of the lighting device 1 according to the present modification is arranged.

As shown in FIG. 12, the light source 200 may include a plurality of series connection portions 210 including a plurality of light emitting elements 22 electrically connected in series with each other. Each of the plurality of series connection portions 210 is electrically connected in parallel with each other between the first terminal 201 and the second terminal 202. In each of the plurality of series connection portions 210, the number of the plurality of light emitting elements 22 in series is such that the voltage ratio is 0.4 (40%) or more and 0.6 (60%) or less. Specifically, the number of series in each of the plurality of series connection portions 210 is equal to each other, for example, 20 pieces.

Since the plurality of series connection portions 210 are electrically connected in parallel in the light source substrate 21, the electrical connection between the light source substrate 21 and the circuit board 61 is an embodiment as shown in FIG. Similarly, it can be performed with two lead wires 64a and 64b. Independent terminals may be provided for each series connection portion 210, or the light source substrate 21 and the circuit board 61 may be electrically connected by three or more lead wires.

As described above, in the lighting device according to the present modification, for example, the light source 200 includes a plurality of series connection portions 210. The plurality of series connection portions 210 are connected in parallel with each other.

As a result, the amount of light can be increased by the plurality of series connection portions 210. Further, since the number of series for each series connection portion 210 is a number in which the voltage ratio is 0.4 (40%) or more and 0.6 (60%) or less, light flicker is suppressed and the current efficiency is improved. Can be enhanced.

(Other)
The lighting device according to the present invention has been described above based on the above-described embodiment, but the present invention is not limited to the above-described embodiment.

For example, a component such as a connector terminal 23 may be provided on the main surface 21b of the light source board 21. Further, the circuit component 62 may be provided on the main surface 61b of the circuit board 61.

Further, for example, the light source 200 and the lighting circuit 100 may be provided on one substrate. That is, the light source substrate 21 and the circuit board 61 may be one inseparable substrate.

Further, for example, the light emitting module 20 may be a COB (Chip On Board) type light emitting module in which the bare chip is directly mounted on the main surface 21a of the light source substrate 21. That is, the light emitting element 22 may be the LED chip itself. In this case, the plurality of LED chips mounted on the light source substrate 21 may be collectively sealed by the sealing member, or one or a plurality of LED chips may be individually sealed. Further, the sealing member may contain a wavelength conversion material such as a yellow phosphor.

Further, for example, the light emitting element 22 may be a semiconductor laser element, an organic EL (Electroluminescence), or an inorganic EL element.

Further, for example, the shape and size of each constituent member shown in the above embodiment, the fixing method between the constituent members, and the like are merely examples, and are not particularly limited. For example, the light emitting module 20 may be a long light emitting module. Specifically, the light source substrate 21 may be a substrate that is long in one direction, and a plurality of light emitting elements 22 may be provided in a row or a plurality of rows in the long direction of the light source substrate 21. Good.

Further, the number of members may be reduced from the lighting device 1 as long as the function as the lighting device is not impaired. For example, the lighting device 1 does not have to include at least one of a housing 10, a reflector 30, a light guide plate 40, a translucent cover 50, a terminal block 70, a circuit case 80, and a mounting plate 90.

Further, the lighting device 1 may include other constituent members. For example, a thin-film adhesive sheet, a resin sheet having high insulation property, a resin sheet having high thermal conductivity, or the like is provided between the main surface 21b of the light source substrate 21 and the main surface 11a of the base portion 11. You may be. That is, the light source substrate 21 and the base portion 11 do not have to be in direct contact with each other. Similarly, the circuit board 61 and the base portion 11 do not have to be in direct contact with each other. For example, a thin film adhesive sheet, a resin sheet having high insulation property, a resin sheet having high thermal conductivity, or the like is provided between the main surface 61b of the circuit board 61 and the main surface 11b of the base portion 11. You may be.

In addition, it is realized by arbitrarily combining the components and functions in each embodiment within the range obtained by applying various modifications to each embodiment and the gist of the present invention. Forms are also included in the present invention.

1 Lighting device 22 Light emitting element 40 Light guide plate 41 Exiting part 42 Incident part 100, 101 Lighting circuit 120 Rectifier circuit 121a, 121b Input terminal 122a, 122b Output terminal 140 Current control circuit 150 Charging current control circuit 200 Light source 201 First terminal 202 2 terminals 210 Series connection C Power storage element D1 Rectifying element (1st rectifying element)
D2 rectifying element (second rectifying element)
D3 rectifying element (third rectifying element)

Claims (6)

Light source and
It is equipped with a lighting circuit that emits light from the light source.
The lighting circuit
A rectifier circuit having a pair of input terminals and a pair of output terminals, rectifying an AC voltage input to the pair of input terminals, and outputting a pulsating voltage from the pair of output terminals.
It has a power storage element that is electrically connected to the light source in series between the pair of output terminals and is charged and discharged based on the pulsating voltage.
The light source includes a series connection including a plurality of light emitting elements electrically connected in series with each other.
The number of light emitting elements in series included in the series connection portion is a number such that the voltage drop due to the series connection portion is 40% or more and 60% or less of the AC voltage.
The series connection portion is a lighting device that emits light based on the pulsating current voltage and the voltage charged in the power storage element. The lighting device according to claim 1, wherein the voltage drop is the sum of the forward voltages of the plurality of light emitting elements included in the series connection portion. The light source is
A first terminal electrically connected to one of the pair of output terminals,
Has a second terminal
The series connection portion is electrically connected between the first terminal and the second terminal.
The lighting circuit further
A current control circuit connected between the second terminal and the other of the pair of output terminals to control the current flowing through the light source.
A charging current control circuit that is electrically connected in series with the power storage element between both ends of the current control circuit and controls the charging current flowing through the power storage element.
A first rectifying element connected between the second terminal and the power storage element and flowing the charging current from the light source toward the power storage element.
A second rectifying element connected between the first terminal and the power storage element and flowing a discharge current from the power storage element toward the light source.
The lighting device according to claim 1 or 2, further comprising a third rectifying element connected between the other of the pair of output terminals and the power storage element and allowing the discharge current to flow by bypassing the charging current control circuit. .. The light source includes a plurality of the series connection portions.
The lighting device according to any one of claims 1 to 3, wherein the plurality of series connection portions are connected in parallel with each other. The lighting device according to any one of claims 1 to 4, wherein the series connection portion is not provided with an electrical branch. In addition, it is equipped with a light guide plate.
The light guide plate
The incident part where the light from the light source is incident and
It has a flat-plate-shaped emitting portion that emits light incident from the incident portion.
The invention according to any one of claims 1 to 5, wherein the incident portion projects from the emitting portion toward the light source and is located inside the emitting portion when the emitting portion is viewed in a plan view. Lighting device.

Images