Luminaire

Abstract

To provide a luminaire that can suitably radiate its inside heat and also prevent snow accretion, ice accretion and dew condensation.SOLUTION: A luminaire 1 has a heat transfer member 7 interposed between heat generating elements 10, 10, ..., which are circuit elements and generate heat, and a translucent cover 6, and then can suppress ice accretion and snow accretion as the heat dissipated by the heat generating elements 10, 10, ... n, are transmitted to the translucent cover 6 through the heat transfer member 7 to warm up the translucent cover 6 and also suppress heat radiation into the device.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a lighting device using light-emitting elements (LEDs) that have the function of preventing snow, ice, and condensation. [Background technology]

[0002] In recent years, there has been a shift towards using light-emitting diode (LED) lighting devices, which are easier to maintain and manage and consume less power than conventional bulb-type devices.

[0003] It is desirable to drive an LED at a constant current, but the range of voltages at which it can light up properly is very narrow, so simply connecting the light-emitting element to a constant-voltage power supply will not allow it to light up stably.

[0004] Therefore, conventional LED lighting devices generally include a drive circuit (lighting circuit) for stably lighting the LEDs.

[0005] Known lighting circuits include a resistor divider type, in which a resistor is placed in series with the LED to suppress fluctuations in the current flowing through the LED to ensure stable lighting, and a series regulator type, in which a control element such as a bipolar transistor, MOSFET, or three-terminal regulator is placed in series with the LED to keep the current flowing through the LED constant to ensure stable lighting.

[0006] On the other hand, because this type of LED lighting device generates less heat than incandescent bulbs, when used outdoors in areas with heavy snowfall, the heat generated by the LEDs alone is not enough to melt the snow or ice that has built up on the translucent cover due to rain or snow, and there is a risk that the LED's light emission will be blocked by the snow or ice.

[0007] In view of this, in recent years, lighting devices have been developed that prevent snow and ice from accumulating by warming a translucent cover using heat generated by an LED (see, for example, Patent Document 1).

[0008] This lighting device, for example, has a heat transfer material interposed between the board on which the LEDs are mounted and the translucent cover, and the heat generated by the LEDs is transferred to the translucent cover via the board and the heat transfer material, thereby warming the translucent cover. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2012-256677 A Summary of the Invention [Problem to be solved by the invention]

[0010] However, with the conventional technology described above, because LEDs generate less heat than light bulbs, there was a risk that even if the heat generated by LEDs was utilized efficiently, it would not be possible to secure enough heat to melt the snow and ice that had adhered to the translucent cover.

[0011] Meanwhile, in this type of LED lighting device, some of the circuit elements that make up the drive circuit (lighting circuit) that stably drives the LEDs generate heat when driven, such as resistors in the resistive voltage divider method and control elements in the series regulator method (hereinafter referred to as heat-generating elements).

[0012] LEDs have the problem of being vulnerable to high temperatures. If the temperature inside the lighting device rises due to heat generated by the heat-generating elements as described above, this may affect the brightness and lifespan of the lighting device, or may even damage the lighting circuit.

[0013] Therefore, generally, in an LED lighting device equipped with this type of light-emitting element, a structure for dissipating heat from the heat-generating element, such as a heat sink, must be provided, which results in problems such as increased costs and hinders miniaturization.

[0014] In view of the above-mentioned problems, the present invention has been made with an object of providing a lighting device that can effectively dissipate heat within the device and prevent snow, ice and condensation from forming. [Means for solving the problem]

[0015] The feature of the invention described in claim 1 for solving the above-mentioned problems in the conventional art is that in an illumination device comprising a light-emitting unit having a light-emitting element and one or more circuit elements constituting a drive circuit for driving the light-emitting element mounted on a substrate, and a translucent cover covering the front side of the light-emitting unit, a heat transfer member is interposed between the circuit element, which is a heat-generating element that generates heat, and the translucent cover, so that heat generated by the heat-generating element is transferred to the translucent cover via the heat transfer member.

[0016] The invention as set forth in claim 2 is characterized in that, in addition to the configuration as set forth in claim 1, the heat generating element is embedded in the heat transfer member.

[0017] The invention as set forth in claim 3 is characterized in that, in addition to the configuration of claim 1 or 2, the light emitting element and the heat generating element are mounted on the same surface of the substrate.

[0018] The feature of the invention described in claim 4 is that, in addition to the configuration of claim 1 or 2, the drive circuit comprises a switching circuit that controls the voltage of the light-emitting element by a switching element, and a protection circuit that absorbs a transient high voltage that occurs when the switch of the switching circuit is turned off, and the heat-generating element is an element that constitutes the protection circuit. Effect of the Invention

[0019] By being provided with the configuration described in claim 1, the lighting device of the present invention can suppress a rise in temperature within the lighting device by dissipating heat generated by the heat-generating elements that constitute the drive circuit (lighting circuit) to the translucent cover via the heat transfer member, and can prevent snow, ice, and condensation from forming on the translucent cover by warming the translucent cover.

[0020] In addition, in the present invention, by providing the configuration recited in claim 2, heat generated by the heat-generating element can be efficiently transmitted to the light-transmitting cover.

[0021] Furthermore, in the present invention, by providing the configuration recited in claim 3, the overall size of the lighting device can be reduced.

[0022] Furthermore, in the present invention, by providing the configuration described in claim 4, it is possible to effectively prevent snow, ice and condensation not only in the main circuit constituting the lighting circuit but also in the elements constituting the circuits associated with the main circuit. [Brief description of the drawings]

[0023] [Figure 1] 1 is a front view showing an example of a lighting device according to the present invention. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a schematic circuit diagram showing a drive circuit of the lighting device according to the embodiment. [Figure 4] FIG. 11 is a front view showing another example of the lighting device according to the present invention. [Diagram 5] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] Next, an embodiment of the lighting device according to the present invention will be described based on the examples shown in Figures 1 to 3. In the figures, reference numeral 1 denotes an LED lighting device.

[0025] As shown in Figures 1 and 2, the lighting device 1 includes a light-emitting unit 5 having a light-emitting element (hereinafter referred to as LED 2) and one or more circuit elements constituting a drive circuit (lighting circuit 3) that drives the LED 2 mounted on a substrate 4, and a light-transmitting cover 6 that covers the front side of the light-emitting unit 5. The LED 2 is stably lit by the lighting circuit 3, and the light emitted from the LED 2 is irradiated through the light-transmitting cover 6.

[0026] In addition, in this lighting device 1, a heat transfer member 7 is interposed between the heat-generating elements 10, 10..., which are circuit elements that generate heat, and the light-transmitting cover 6, and the heat generated by the heat-generating elements 10, 10... is transferred to the light-transmitting cover 6 via the heat transfer member 7, thereby preventing snow and ice from accumulating on the light-transmitting cover 6 and preventing condensation on the light-transmitting cover 6.

[0027] The light-emitting unit 5 is formed by surface-mounting a light-emitting element consisting of an LED 2, one or more circuit elements that constitute a drive circuit (lighting circuit 3) that drives the LED 2, and a power supply 8 that supplies power to the lighting circuit 3 on the same side of a substrate 4, and the LED 2, the circuit elements, and the power supply 8 are appropriately connected by wiring 9 made of copper foil or the like to form the lighting circuit 3.

[0028] In this embodiment, the case where the power supply 8 is mounted on the substrate 4 has been described, however, the power supply 8 may be one in which power is supplied from an external power supply to the light-emitting unit 5 via a connector or a lead wire connection portion mounted on the substrate 4, or the like.

[0029] The light emitting element is, for example, a light emitting diode (LED 2) sealed in a package, and can be surface mounted on the substrate 4.

[0030] The lighting circuit 3 is, for example, as shown in FIG. 3, configured by a resistor voltage dividing circuit, in which one or more resistors 10 are connected in series with the LED 2 as a circuit element, and is connected to a DC power source 8.

[0031] The resistor 10, which is a circuit element, is a heat generating element that generates heat at a certain level or more when a current flows through it.

[0032] The resistors 10 are, for example, rectangular chip resistors, and are surface-mounted on the outer edge of the substrate 4 at intervals in the circumferential direction.

[0033] The number of resistors 10, the resistance value and arrangement of each resistor 10 are set taking into consideration a sufficient amount of heat to suppress icing and snow accumulation when transferred to the light-transmitting cover 6 via the heat transfer member 7.

[0034] The heat transfer member 7 is made of a material with excellent thermal conductivity such as silicone rubber, and is formed in a circular ring shape around the peripheral edge of the substrate 4. The back surface of the translucent cover 6 is fixed to the surface portion via a thermally conductive adhesive or the like, and a resistor 10, which is a heat-generating element, is embedded inside.

[0035] The material constituting the heat transfer member 7 is preferably a material having high thermal conductivity, for example, thermally conductive silicone rubber (about 1.3 W / m K) in which the thermal conductivity is improved by compounding inorganic fillers into silicone rubber. However, as long as it has a certain level of thermal conductivity, general organic rubber (about 0.12 to 0.18 W / m K) or silicone rubber with excellent thermal conductivity (about 0.2 W / m K) can also be used.

[0036] The light-transmitting cover 6 is made of a transparent or semi-transparent material such as resin or glass, and is formed in a plate or hemispherical shape.

[0037] In the lighting device 1 configured in this manner, when the light-emitting element (LED 2) is turned on, a current flows through the heat-generating element (resistor 10) constituting the drive circuit (lighting circuit 3), causing the resistor 10 to generate heat. At that time, since the heat-transmitting element (resistor 10) constituting the drive circuit (lighting circuit 3) is interposed between the heat-generating element (resistor 10) and the translucent cover 6, the heat generated by the resistor 10 is transmitted to the translucent cover 6 through the heat-transmitting member 7, and the translucent cover 6 is heated, so that the formation of ice or snow on the translucent cover 6 and the formation of condensation on the translucent cover 6 can be suppressed.

[0038] Furthermore, in this lighting device 1, heat generated by the resistor 10 is transferred to the translucent cover 6 via the heat transfer member 7, and is not easily dissipated into the interior where the substrate 4 and the LEDs 2 are arranged. This reduces the adverse effects on the brightness and lifespan of the LEDs 2, which are sensitive to high temperatures, and also prevents damage to the lighting circuit 3.

[0039] Furthermore, in this lighting device 1, heat is not easily dissipated inside the substrate 4 or the area in which the LEDs 2 are arranged, so even if the LEDs 2 and the heat-generating element (resistor 10) are mounted on the same surface of the substrate 4, the impact on the LEDs 2 is small, and a structure for dissipating heat generated by the heat-generating element, such as a heat sink, is not required, which allows for greater freedom in designing the entire device and makes it more compact.

[0040] In the above embodiment, the heat transfer member 7 is formed in a circular ring shape covering the peripheral portion of the substrate 4, but the form of the heat transfer member 7 is not limited to this. For example, as shown in Figures 4 and 5, a heat transfer member 7 may be interposed between each heat-generating element 10 and the light-transmitting cover 6 for each heat-generating element 10.

[0041] The lighting circuit 3 is not limited to the above embodiment, and can be configured with multiple types of circuit elements depending on various conditions such as the performance, use, and installation location of the lighting device 1. For example, although not shown, it may be a series regulator type in which a control element such as a bipolar transistor, MOSFET, or three-terminal regulator is arranged in series with the LED 2, and the current value flowing through the LED 2 is kept constant to ensure stable lighting. Furthermore, the heat generating element is not limited to the above resistor, and in the case of a series regulator type, a control element such as a bipolar transistor, MOSFET, or three-terminal regulator can be used as the heat generating element.

[0042] The drive circuit may also include a switching circuit that controls the voltage of the LED 2 by a switching element, and a protection circuit (snubber circuit) that absorbs a transient high voltage that occurs when the switch of the switching circuit is turned off.

[0043] As this protection circuit (snubber circuit), for example, one in which a resistor and a capacitor are arranged in series is known, and since the resistor that constitutes this circuit generates heat, the resistor can be used as a heat-generating element.

[0044] In the above embodiment, the lighting circuit 3 has been described as an example of a drive circuit, but the present invention can be applied to circuits used for turning on and off light emitting elements, timer control, and all other drives. [Explanation of symbols]

[0045] 1 Lighting equipment 2 LED (light emitting element) 3 Lighting circuit 4. Board 5 Light Emitting Unit 6. Translucent cover 7 Heat transfer materials 8 Power 9 Wiring 10 Resistance

Claims

1. A lighting device including a light-emitting unit in which a light-emitting element and one or more circuit elements constituting a drive circuit for driving the light-emitting element are mounted on a substrate, and a light-transmitting cover covering a front side of the light-emitting unit, a heat transfer member is interposed between the heat generating element which is the circuit element and generates heat and the light transmitting cover; a heat generating element configured to transmit heat to the light-transmitting cover via the heat transfer member;

2. The lighting device according to claim 1 , wherein the heat generating element is embedded in the heat transfer member.

3. 3. The lighting device according to claim 1, wherein the light emitting element and the heat generating element are mounted on the same surface of the substrate.

4. the drive circuit includes a switching circuit that controls a voltage of the light-emitting element by a switching element, and a protection circuit that absorbs a transient high voltage generated when a switch of the switching circuit is cut off; The lighting device according to claim 1 , wherein the heat generating element is an element that constitutes the protection circuit.

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