JP2012014867A - Excessive temperature rise preventive lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device which is used under environments such as severe temperature changes, large changes of cooling conditions, and severe heat-radiation conditions and can restrain excessive temperature rise.SOLUTION: The lighting device 1 includes light-emitting elements 6, a power source 3 can vary power applied to the light-emitting elements, a temperature sensor 4 can measuring temperature of the light-emitting elements, and a control circuit 5 for controlling the power source in response to values of the temperature sensor 4. An amount of power applied to the light-emitting elements is controlled to make detected temperature of the temperature sensor 4 become specific setting temperature.

Description

In the present invention, it is difficult to mount an illumination device used in an environment where the temperature changes drastically, an environment where the cooling condition changes greatly, an environment where the heat dissipation condition is severe, such as underwater or in both seawater and air, and a conventional illumination device. The present invention relates to a lighting device used in a narrow place.

For example, in a conventional patent (Japanese Patent Laid-Open No. 2005-294816), a light emitting element is forcibly cooled using a Peltier element in order to stabilize the temperature of the light emitting element. When considering a lighting device that is used in an environment where the temperature of the light emitting element rapidly increases by this method, it is a precondition that a large amount of power is required to cool the light emitting element strongly.
In Japanese Patent Application No. 2006-539931, the current is controlled when the temperature exceeds a certain value. However, since the control is performed after the temperature exceeds the set value, a sudden change in the environment is unavoidable. However, it is difficult to cope with smoothness, and it is difficult to avoid damage to the light source because the excess amount of temperature is large.
Recently, LEDs have been increasingly used as light emitting elements for illumination. Since the light emitting element of an LED is extremely small compared to a conventional light bulb, fluorescent lamp, etc., it is possible to manufacture a small high-luminance lighting device that cannot be considered with a conventional light source. However, although the LED heat generation is small, if the power is applied as it is, the light emitting element will be overheated and the light emitting life will be shortened or it may be broken in the worst case. When installing a small LED light source in a narrow place where a lighting device could not be installed in the past, in most cases such a narrow place has poor airflow due to poor air flow. Since the electric power to be applied is determined after considering the change in the cooling state and setting an excessive safety factor, it is inevitably darkened.
Conventionally, it has been common and important to keep the illumination brightness constant for an illumination device. Therefore, the lighting device usually has a built-in cooling device or a large heat dissipation device as a countermeasure against excessive temperature rise, and both the lighting device and the member that holds the lighting device have become large. .

JP2005-294816 Japanese Patent Application 2006-539931

Light sources for fisheries, etc. used underwater are mainly used underwater, so the lighting device is cooled with water and a greater heat dissipation effect can be obtained than in air. Is possible.
However, when the illuminating device is pulled out from the water, the temperature of the illuminating device suddenly rises when the illuminating device is pulled out from the water and exposed to the atmosphere, and the light source may be deteriorated or broken in the worst case. This is also the case when the lighting device is submerged. If the power is turned on in the atmosphere, the temperature of the light source is excessively raised before entering the water, and the life of the lighting device is shortened. In other words, it could not be sunk or pulled up unless the power was turned off.
If it can be used even in the atmosphere, a radiator is required, and the lighting device becomes large.

Although the case where temperature protection is implemented using a heat-sensitive cutout switch is also conceivable, in this case, the lighting device blinks and continuous illumination cannot be performed. Similarly, when power is reduced to a certain value, flickering occurs in the same manner, and the luminance is lowered more than necessary. Further, since the response is made after the set value is exceeded, there is a risk that the temperature rise will greatly exceed the set value in a short time.
SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and is to provide a lighting device for both underwater and aerial that is small in size and can cope with a sudden change in the environment surrounding the lighting device, and has a long life and little luminance fluctuation. .

The present invention is also characterized by voluntarily changing the illuminance in accordance with the installation environment.
For example, in the case of underwater illumination, light transmission is poor and dark underwater, so that a large luminance is required for the illumination device. However, when pulled up from the water, naturally the atmosphere is brighter than the water and the light transmission is better, so the required illuminance is lower than in the water.
In the case of an outdoor light, unless it is a special installation environment, it is bright in the daytime, so no lighting is necessary, and the outside air temperature is high, and the outside air temperature decreases as the lighting is necessary from nightfall to midnight.
In other words, the illuminance required for the lighting device often increases as the outside air temperature decreases.
If the lighting device according to the present invention is used in the installation environment as described above, it is possible to provide a lighting device that is small and has a minimized heat sink, that is, a small and lightweight lighting device that is cut as much as possible. Since the lighting device is small and lightweight, it is possible to reduce the number of members for holding the lighting device. Therefore, the use of resources such as metals can be reduced, and the environment is extremely considered.

The present invention includes a light-emitting element, a power source that can vary the power applied to the light-emitting element, a temperature sensor that measures the temperature of the lighting device, and a control circuit that controls the power source applied to the light-emitting element based on the value of the temperature sensor. Thus, PID control is performed on the power applied to the light emitting element so that the temperature of the lighting device becomes the set temperature when the temperature enters the control zone. In short, since the power applied to the light emitting element is controlled based on the accumulated data of the temperature rise / fall so far so that the temperature of the light emitting element becomes the set temperature, it is possible to prevent excessive temperature rise. Naturally, in environments such as underwater, a large cooling capacity can be expected, so even if the power applied to the light emitting element reaches the maximum output of the lighting device, it does not reach the target set temperature, so it can always be used with the maximum light intensity. It is.

In addition, by providing a control circuit that constantly supplies power to the light emitting element up to the set temperature, the lighting device mainly determines and determines the amount of power to be applied to the light emitting element according to the installed environment. It is possible to extract the maximum luminance according to the environment, and it is possible to avoid a sudden luminance change (blinking, flickering, etc.) by continuous control without lowering the luminance more than necessary. In addition, power for cooling the element is not consumed. Therefore, it is possible to provide a lighting device that can be used stably even if the environment changes suddenly, and that adapts to the environment with long life and power consumption.

As described above, since the lighting device of the present invention determines and determines the amount of power that the lighting device mainly applies to the light emitting element according to the installed environment, the maximum luminance corresponding to the environment at that time is extracted. Therefore, the luminance is not lowered more than necessary, and a sudden luminance change can be avoided by continuous control. In addition, it is possible to obtain a lighting device that is small, lightweight, has a long life, and consumes little power.

It is a block diagram which shows the structural example of the illuminating device of this invention. It is an example of sectional drawing of the illuminating device used by both the underwater and the air of this invention. It is an example of the top view of the illuminating device used by both the underwater and the air of this invention.

An embodiment of a lighting device according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a lighting device according to the present invention. As shown in FIG. 1, an illumination device 1 according to an embodiment of the present invention includes an illumination unit 2, a power supply unit 3 that supplies power to the illumination unit 2, and a temperature sensor 4 that detects the temperature of the illumination unit 2. The control unit 5 controls the output power of the power supply unit 3 based on the detection signal of the temperature sensor 4.
The light source 6 of the illumination unit 2 uses a plurality of high-intensity white light-emitting diodes or light-bulb-colored light-emitting diodes. These light emitting diodes are mounted on a substrate 7 made of a material having high thermal conductivity such as aluminum or CEM-3.
In order to light the light emitting diode efficiently in the power supply unit 3, a constant current power supply circuit is used, and the light emitting diode of the illumination unit 2 can be driven with a predetermined constant current value. Further, it has a function of varying the output current by a control signal from the control unit 5.
The temperature sensor 4 is mounted on a substrate 7 having a high thermal conductivity on which the light emitting diodes of the illumination unit 2 are mounted. By mounting the light emitting diode and the temperature sensor 4 on the same substrate 7 having high thermal conductivity, the temperature sensor 4 can detect a temperature substantially equal to the junction temperature of the light emitting diode.

As a matter of course, the temperature sensor 4 is mounted in the vicinity of the light emitting diodes in the portion where the temperature rise is considered to be highest on the substrate 7 on which the light emitting diodes are mounted, that is, in the portion where the light emitting diodes are most densely packed.
A microcomputer is used for the control unit 5. The microcomputer has a function of reading the output value of the temperature sensor 4 by a method such as A / D conversion or serial communication. A target temperature set value is input in advance to the microcomputer. This temperature set value may be variable by external communication, a setting switch, or the like.

In addition, an arithmetic expression for PI control or PID control is programmed in the microcomputer, and a control value output to the power supply unit 3 is always calculated from the temperature measurement value and the target temperature setting value. This control value is converted into a voltage value by a D / A converter or output to the power supply unit 3 by communication means such as serial communication. By optimizing the control constant of PI or PID control, the lighting unit 2 can keep a constant temperature with almost no overshoot in response to a sudden change in the external environment, and output to the power source unit 3 It is possible to eliminate the blinking and flickering of the light emitting diode due to a rapid change in value, and to realize stable lighting of the light emitting diode.

When the lighting device 1 is used in an environment with excellent heat dissipation characteristics such as underwater, the detected value of the temperature sensor 4 reaches the target set value even if the current value of the maximum output is supplied from the power supply unit 3 to the lighting unit 2. do not do. Therefore, stable illuminance can be obtained at the maximum output value in an environment such as underwater.
As described above, the block diagram shown in FIG. 1 provides the lighting device 1 that controls the power supplied to the lighting unit 2 so that the measurement value detected by the temperature sensor 4 becomes the target set value.
As described above, the temperature sensor 4 is mounted on the substrate 7 on which the light emitting diodes of the illumination unit 2 are mounted. However, even if the control unit 5 and the power supply unit 3 are mounted on the same substrate 7 on which the light emitting diodes are mounted. Even if it is mounted on another substrate, there is no problem in carrying out the present invention.

Next, the present invention is most effective for an illuminating device used both underwater and in the air, such as a fish-collecting lamp, and an embodiment in this case will be described.
As shown in the cross-sectional view of FIG. 2 and the top view of FIG. 3, the illuminating device 20 used both underwater and in the air is a rust-resistant metal such as SUS316 or an aluminum metal whose surface has been subjected to rust prevention treatment. A substrate 23 on which a light emitting diode 30 and a temperature sensor 31 are mounted is fixed to a base plate 21 also serving as a heat radiating plate with screws 27 via a paste 24 having a high thermal conductivity such as silicon grease. Waterproofing is performed by fixing the transparent resin cover 22 to the base plate 21 with screws 26 in the form of sandwiching an O-ring 25 made of silicon rubber or fluorine rubber. As shown in FIG. 3, the electric wire 35 that supplies electric power is drawn into the illumination device 20 from the outside through a cord bush 28 that is waterproofed with an O-ring or the like fixed to the cover 22.
The waterproofing process is performed by the O-ring 25 and the waterproof cord bush 28. As the substrate 23, a CEM-3 substrate or an aluminum substrate having a high thermal conductivity is used. In this embodiment, a pattern is formed on the upper surface of the substrate 23, and electronic components such as the light emitting diode 30 are mounted in a surface-mounted form. .

The heat generated by the light emitting diode 30 is directly conducted to the base plate 21 through the substrate 23 and the high thermal conductive paste 24. With such a structure, the heat of the light emitting diode 30 is directly transmitted to the base plate 21 through the heat conductive material. In an underwater environment with good heat dissipation characteristics, heat is sufficiently dissipated into the water from the base plate 21 that is in direct contact with water, and the temperature rise is suppressed. Therefore, the high thermal conductive paste 24 in contact with the base plate 21, the substrate 23, and the light emitting diode Since 30 does not overheat, miniaturization is possible without using a special heat sink.

Since the lighting device of the present invention determines and determines the amount of power that the lighting device mainly applies to the light emitting element according to the installed environment, it is possible to draw the maximum luminance according to the environment at that time, Since the brightness can be avoided by continuous control without lowering the brightness more than necessary, lighting used in both underwater and air environments, especially in environments where temperature changes are severe and where heat dissipation conditions are severe. Useful for equipment etc.

DESCRIPTION OF SYMBOLS 1 Illuminating device 2 Illuminating part 3 Power supply part 4 Temperature sensor 5 Control part 6 Light source 7 Board | substrate 20 Illuminating device
21 Base plate 22 Resin cover 23 Substrate 24 High heat conductive paste 25 O-ring 26 Screw 27 Screw 28 Cord bush 30 Light emitting diode 31 Temperature sensor 35 Electric wire

Claims (6)

A lighting device comprising: a light emitting element; a power source capable of varying power applied to the light emitting element; a temperature sensor capable of measuring a temperature of the light emitting element; and a control circuit for controlling the power source in accordance with a value of the temperature sensor. And a lighting device characterized in that the amount of electric power applied to the light emitting element is controlled so that a temperature detected by the temperature sensor becomes a specific set temperature. 2. The lighting device according to claim 1, wherein the control method for controlling the amount of electric power applied to the light emitting element according to the value of the temperature sensor is PI control or PID control. The lighting device according to claim 1, wherein the light emitting element is a UV light source. The lighting device according to claim 1, wherein the light emitting element is a light emitting diode. The lighting device according to any one of claims 1 to 4, wherein the lighting device is waterproof and can be used in water or in seawater and in the air. 6. The lighting device according to claim 1, wherein heat generated by the light emitting element is directly radiated to water or seawater and the atmosphere directly through a heat conductive material.