JP4299006B2 - Portable LED lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a LED lighting device, and more particularly to a portable LED lighting device can be suitably applied to a portable lighting device and bicycle headlight using a high-brightness white LED single or very few.
[0002]
[Prior art]
In order to ensure a predetermined luminance, a miniature light bulb capable of flowing a current of 300 mA to 1000 mA is used as a light source in a conventional portable lighting device or a bicycle headlamp, but a filament is used. Therefore, there is a problem that the life is short and the battery life is short because the light conversion efficiency is low.
[0003]
On the other hand, the LED has an advantage that it has a long life and high light conversion efficiency, but since it can only flow a current of about 30 mA at the maximum, it is difficult to obtain a desired luminance. Mainly applied to signal lamps and the like provided with LED elements.
[0004]
In addition, a large-scale LED light source using a large number of LED elements has been proposed as a light source for illumination and display, and further, power is used so that the temperature of the LED detected by the temperature detection element by the control means is constant. Control is disclosed (for example, refer to Patent Document 1).
[0005]
[Patent Document 1]
JP-A-11-162660 [0006]
[Problems to be solved by the invention]
By the way, in order to realize a portable lighting device using an LED element, it is necessary to have a compact configuration using a single or a very small number of LED elements. It is necessary to use an LED element with high brightness as a single unit. However, since such an LED element generates a large amount of heat, it is energized according to the temperature of the LED element so that the LED element does not break down due to its own heat generation. It is necessary to control.
[0007]
Therefore, as shown in the above-mentioned Patent Document 1, it is considered that a temperature detection element is disposed in the vicinity of the LED element to detect the temperature of the LED element so that illumination with the maximum brightness can be always performed. However, if the temperature detecting element is provided in the portable lighting device, it cannot be made compact, and there is a problem that the cost increases.
[0008]
In view of the above-described conventional problems, an object of the present invention is to provide a portable LED illuminating device that can realize bright illumination with a compact and inexpensive configuration without causing destruction of an LED element.
[0009]
[Means for Solving the Problems]
The portable LED lighting device of the present invention controls the drive current of an LED using a battery housing part, a light emitting part composed of a single or very few high-intensity LEDs and its substrate, and a battery housed in the battery housing part as a power source. A portable LED illuminating device comprising: a current control means for performing the above operation; a reflector that emits light from the LED toward one side; and a lens that collects the light emitted from the reflector; thermally coupled to the central portion, the reflecting plate is thermally coupled to the substrate, LED forward voltage across the temperature sensing means for detecting the junction temperature of the LED (hereinafter, sometimes referred to as Vf.), it is an one wherein the LED based on the LED junction temperature is detected and a control means for controlling the current control means so as not to destroy the heat generation of itself.
[0010]
According to this configuration, in a portable LED lighting device having a compact configuration having a light emitting unit composed of a single or a very small number of high-intensity white LEDs, the junction of the LED can be formed with a compact and inexpensive configuration that does not use a temperature detection element. The temperature can be detected, and energization control of the LED can be performed so that the LED does not break down due to its own heat generation , based on heat radiation to the surroundings due to thermal coupling between the LED substrate and the reflector .
[0011]
In addition, when the control means controls the current control means so that the junction temperature is constant, the brightness of the limit is always obtained within a range in which no breakdown occurs by bringing the constant value of the junction temperature close to the limit value. be able to.
[0013]
In addition, the portable LED lighting device of the present invention includes a battery housing portion, a light emitting portion composed of a single or very few high-brightness LEDs and its substrate, and a battery that is housed in the battery housing portion as a power source. In a portable LED illumination device, comprising: a current control means for controlling the light; a reflector for emitting light from the LED toward one side; and a lens for collecting the light emitted from the reflector; is a high luminance have row energization control by the PWM control with respect to the white LED, comprising: a light control means for setting the brightness of the illumination, the control means for controlling the current control means according to the setting of the dimming means The LED is controlled by PWM control according to the set value by adjusting the dimming means based on the heat dissipation to the surroundings due to the thermal coupling between the LED substrate and the reflector. Against By but controlled, it is possible to obtain an illumination of any brightness.
[0015]
The portable LED lighting device according to the present invention further includes means for detecting the battery life of the power source and control means for performing a warning operation when the battery life approaches a limit. With the use of the LED, when the battery life approaches and the battery voltage drops below a certain value, the light emission of the LED suddenly stops and the light turns off unexpectedly By being warned, appropriate measures can be taken, and usability is improved.
[0016]
As the warning operation, it is preferable to blink the high-intensity white LED, operate the warning display means, or gradually reduce the lighting by gradually decreasing the energization amount to the high-intensity white LED. is there.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of a portable illumination device to which the LED illumination device of the present invention is applied will be described with reference to FIGS.
[0018]
First, the device configuration of the portable illumination device will be described with reference to FIG. In FIG. 1, reference numeral 1 denotes a portable illumination device such as a flashlight that uses a small battery as a power source, and includes an LED light emitting unit 3 composed of a single high-intensity white LED 2 as a light source. 5 is disposed.
[0019]
The case 5 has a main body case 10 having a battery housing portion 6 for housing the battery 4, a light source housing portion 9 for housing the LED light emitting portion 3, its substrate 7, and a control portion 8 for controlling energization of the LED light emitting portion 3. And a front case 13 for accommodating and holding the reflecting member 11 and the condensing lens 12 is screwed to the front portion of the light source accommodating portion 9 and is opened at the rear end surface of the battery accommodating portion 6. The battery insertion opening is opened and closed by the battery lid 14.
[0020]
The high-intensity white LED 2 that constitutes the LED light-emitting unit 3 has a rated current value of about 350 mA and has a capability of allowing a maximum current of 500 mA to flow, thereby enabling a flashlight, a bicycle headlight, etc. It is possible to radiate light having a brightness that can be used. Note that the rated current value of the high-intensity white LED 2 can be 100 mA to 1000 mA, and 350 mA to 500 mA is suitable because it provides the necessary luminance and does not cause excessive power consumption.
[0021]
The reflection member 11 is formed in a bowl shape curved toward the front opening 11a so as to reflect the light from the LED light emitting unit 3 substantially in one direction, and is made of a metal material having a high heat transfer coefficient. The LED light emitting unit 3 is thermally coupled to the central portion thereof. The substrate 7 of the LED light emitting unit 3 is also made of a metal material having a high heat transfer coefficient, and the central portion of the reflecting member 11 is also thermally coupled to the substrate 7.
[0022]
The condensing lens 12 is disposed in the front opening 11 a of the reflecting member 11 and is made of a transparent resin, and a heat insulating member 15 is interposed between the reflecting member 11 and the lens 12.
[0023]
In the control unit 8, as shown in FIG. 2, the battery 4, the current limiting resistor 16, the high-intensity white LED 2, and the PWM control unit 17 that performs energization control on the high-intensity white LED 2 are connected in series. Further, a Vf detection means 18 for detecting Vf of the high brightness white LED 2 and a temperature detection means 19 for detecting the junction temperature of the high brightness white LED 2 based on a detection signal from the Vf detection means 18 are provided. The PWM control means 17 is controlled by the control means 20. Further, the control means 20 outputs a timing signal for outputting a detection signal to the temperature detection means 19 to the Vf detection means 18 and also receives detection signals from the Vf detection means 18 and the temperature detection means 19. .
[0024]
Further, in order to detect the battery life of the battery 4, a battery voltage detection means 21 is provided, and the detection signal is inputted to the control means 20, and a warning display means 22 for warning that the battery life is near by the control means 20. It is configured to operate. Further, a command signal from a light control means 23 for adjusting and setting the brightness of the high brightness white LED 2 is input to the control means 20.
[0025]
Next, the operation of the portable lighting device 1 having the above configuration will be described. Light is emitted when a current controlled by the PWM control means 17 flows from the battery 4 to the high-intensity white LED 2 of the LED light emitting unit 3, and the light is emitted from the front opening 11 a by the reflecting member 11 in almost one direction. The desired area is illuminated with the required illuminance by being emitted toward the target. Moreover, even when the amount of heat generated is increased by passing a large current of about 350 mA to 500 mA through the high-intensity white LED 2 of the LED light emitting unit 3, the heat generated in the LED light emitting unit 3 is reflected by the reflecting member 11. It is possible to effectively dissipate heat by being transferred to the surroundings. Therefore, the LED light emitting unit 3 is reliably prevented from being overheated with a compact configuration without separately providing a large heat radiating means, and the LED light emitting unit 3 is used. A long-life portable illumination device 1 can be obtained.
[0026]
In addition, since the condensing lens 12 is disposed in the front opening 11a of the reflecting member 11, the light emitting portion of the high-intensity white LED 2 is not a point light source, and the light emission angle is large. While the illumination range is expanded and a predetermined illuminance cannot be obtained, by condensing with the lens 12, a predetermined illuminance can be secured in a required illumination area, and between the lens 12 and the reflecting member 11. It is possible to prevent the lens 12 from being adversely affected or damaged by heat even when the reflective member 11 as the heat radiating member is heated to a high temperature by the heat insulating member 15 interposed therebetween.
[0027]
And the energization control with respect to high-intensity white LED2 by the said PWM control means 17 is performed as follows. In other words, the control means 20 causes a low current to flow for an extremely short period of time so that the illuminance reduction is not noticed to the person at appropriate time intervals, and the Vf of the high brightness white LED 2 at that time is detected by the Vf detection means 18. Based on the detection result, the temperature detecting means 19 estimates and detects the junction temperature. Since the Vf of the high-intensity white LED 2 and the junction temperature have a correlation as shown in FIG. 3, even if a temperature detection element is not provided and the temperature is not detected, the correlation of FIG. Based on this, the junction temperature can be estimated and detected.
[0028]
The control means 20 outputs an energization command to the PWM control means 17 so that the detected junction temperature becomes a constant temperature close to the maximum temperature within the temperature range in which the high-intensity white LED 2 is not destroyed, and PWM control is performed. Energization control is performed by means 17. Thereby, even if Vf of the high-intensity white LED 2 varies, the energization control is performed so that the high-intensity white LED 2 does not break down, and it is possible to always illuminate with the limit brightness within the range. Therefore, it is possible to perform energization control so that the high-intensity white LED 2 is not destroyed by its own heat generation with a compact and inexpensive configuration that does not use a temperature detection element.
[0029]
Further, when the user adjusts the illuminance in a stepless or stepwise manner with the light control means 23, the command signal is input to the control means 20, and the energization command is output from the control means 20 to the PWM control means 17. The energization control is performed by the PWM control means 17 so as to obtain a desired illuminance. At that time, of course, the maximum value of the current value is limited so that the high-intensity white LED 2 is not destroyed. Thus, by adjusting and setting the light control means 23, it is possible to obtain illumination with an arbitrary brightness.
[0030]
Further, the output voltage of the battery 4 is detected by the battery voltage detecting means 21, and the warning is given by the control means 20 before reaching the life of the battery 4 where the output voltage drops to a voltage at which the high brightness white LED 2 cannot be turned on. The display means 22 is activated. This warns the user that the battery 4 is near the end of its life and prevents the occurrence of a situation in which the high-intensity white LED 2 suddenly turns off and cannot be illuminated at all.
[0031]
Further, instead of or together with the operation of the warning display means 22, the PWM control means 17 may be controlled so that the high-intensity white LED 2 blinks when the battery 4 approaches the end of its life. The PWM control means 17 may be controlled so that the luminance gradually becomes darker.
[0032]
In addition, as a power supply control method for the high-intensity white LED 2, instead of outputting a power supply command from the control means 20 to the PWM control means 17 so that the junction temperature detected by the temperature detection means 19 becomes constant as described above. The control means 20 outputs a current value (I) command to the PWM control means 17 so that the power value (W) of the product of the voltage value (Vf) and the current value (I) is constant. Well, if it does so, even if Vf of high-intensity white LED 2 varies, illumination with fixed illuminance can always be performed.
[0033]
Next, a second embodiment of a portable lighting device to which the LED lighting device of the present invention is applied will be described with reference to FIG. Since the apparatus configuration is the same as that of the first embodiment, the description thereof is omitted, and the configuration of the control unit is also given the same reference numerals for the same components as those of the first embodiment, and the description thereof is omitted. Only the differences will be described.
[0034]
In the said 1st Embodiment, although the Vf detection means 18 and the temperature detection means 19 were provided and the junction temperature of the high-intensity white LED 2 was monitored and electricity supply control was shown, in this embodiment, A positive temperature characteristic resistance element 24 is disposed so as to be thermally coupled to the high luminance white LED 2, and the positive temperature characteristic resistance element 24 is connected in series to the high luminance white LED 2.
[0035]
With this configuration, when the junction temperature of the high-intensity white LED 2 is increased, the resistance value of the positive temperature characteristic resistance element 24 is increased accordingly. Is prevented from being increased, and a drive current is applied to the high-intensity white LED 2 so as to be always equal to or lower than a predetermined junction temperature, thereby preventing the high-intensity white LED 2 from being destroyed.
[0036]
【The invention's effect】
According to the portable LED lighting device of the present invention, in a compact configuration LED lighting device having a light emitting portion composed of a single or very few high-intensity white LEDs, a compact and inexpensive configuration without using a temperature detecting element. It is possible to detect the junction temperature of the LED, and to control the energization of the LED so that the LED does not break down due to its own heat generation , based on the heat radiation to the surroundings due to the thermal coupling between the LED substrate and the reflector. it can.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of a portable illumination device according to a first embodiment of an LED illumination device of the present invention.
FIG. 2 is a configuration diagram of a control unit according to the embodiment.
FIG. 3 is a correlation diagram of LED forward terminal voltage (Vf) and junction temperature.
FIG. 4 is a configuration diagram of a control unit according to a second embodiment of the LED lighting device of the present invention.
[Explanation of symbols]
1 Portable illumination device (LED illumination device)
2 High brightness white LED
3 LED light emitting unit 4 battery 17 PWM control means (current control means)
18 Vf detection means 19 Temperature detection means 20 Control means 22 Warning display means 23 Dimming means 24 Positive temperature characteristic resistance element

Claims (7)

A battery housing unit, a light emitting unit comprising a single or very few high-brightness LEDs and its substrate , a current control means for controlling the drive current of the LED using a battery housed in the battery housing unit as a power source , and light from the LED In a portable LED illuminating device including a reflecting plate that emits light toward one side and a lens that collects light emitted from the reflecting plate ,
The LED is thermally coupled to the central portion of the reflector, the reflector is thermally coupled to the substrate, and temperature detecting means for detecting the junction temperature of the LED from the forward voltage across the LED, and the detected junction of the LED portable LED lighting apparatus characterized by comprising a control means for controlling the current control means so as not to destroy the heat generated LED is itself based on the temperature. 2. The portable LED lighting device according to claim 1, wherein the control means controls the current control means so that the junction temperature becomes constant. A battery housing unit, a light emitting unit comprising a single or very few high-brightness LEDs and its substrate , a current control means for controlling the drive current of the LED using a battery housed in the battery housing unit as a power source , and light from the LED In a portable LED illuminating device including a reflecting plate that emits light toward one side and a lens that collects light emitted from the reflecting plate ,
LED is thermally coupled to the central portion of the reflector, the reflector is thermally coupled to the substrate, the current control means have row energization control by the PWM control with respect to high-intensity white LED, the brightness of illumination A portable LED illuminating device comprising: a light control unit for setting the current control unit; and a control unit for controlling the current control unit according to the setting of the light control unit. The portable LED illumination according to any one of claims 1 and 3, further comprising: means for detecting a battery life of the power supply; and control means for performing a warning operation when the battery life approaches a limit. apparatus. The portable LED lighting device according to claim 4 , wherein the control means blinks the high-intensity white LED as a warning operation. 5. The portable LED lighting device according to claim 4 , wherein the control means operates the warning display means as a warning operation. The portable LED lighting device according to claim 4 , wherein the control means gradually decreases the energization amount for the high-intensity white LED as a warning operation.

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