JP5025682B2 - LED lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lighting device for detecting emission intensity of a plurality of colors of LEDs from a color sensor in a simple structure, carrying out feedback control based on the detected value, and suppressing a color shift caused by temperature rise of the LEDs after lighting and by ageing deterioration, and keeping constant an emission color. <P>SOLUTION: The LED lighting device includes a plurality of LEDs 5 with different emission colors, a substrate 6 mounted with the LEDs 5, a color sensor 3a for detecting emission intensity of the LEDs 5, and a lighting device case 7 for housing the substrate 6. Furthermore, the color sensor 3a is arranged on a surface opposite side of a surface on which the LEDs 5 on the substrate 6 are mounted and slits 11 for transmitting light is arranged on the substrate 6, and the light device case 7 includes a concave shaped recess 12 for light reflection formed at a site where the color sensor 3a arranged on the substrate 6 and the slits 11 for light transmission are positioned. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an LED illumination device that performs illumination mainly using LEDs, and more particularly to an LED illumination device that generates white light.

  In recent years, many LED illumination devices using LED light sources have been proposed as next-generation illumination that replaces incandescent bulbs and fluorescent lamps. Such LED lighting devices have the advantages of long life and energy saving, and are expected to become increasingly popular in the future.

  In order to obtain white light from an LED for illumination, a white LED is generally used. White LEDs combine white and yellow to obtain white light by combining a yellow phosphor excited by blue light with an LED chip that generates blue light. In such a system, since there are wavelength peaks in the vicinity of 460 nm and 560 nm, and other wavelength components are not included, the color rendering property that reproduces the original color of the illuminated material is poor, and the light color is selected by the yellow fluorescence. Since it is determined by the combination with the body, it cannot be used for purposes such as changing the light color such as a light bulb color or day white. Moreover, conversion loss due to the yellow phosphor also occurs.

  On the other hand, as another means for obtaining white light, a method of obtaining white light by mixing three primary colors of light by combining only a plurality of LEDs having wavelengths of three primary colors of red, blue, and green without using a phosphor. There is. According to this method, there is no conversion loss due to the yellow phosphor, high efficiency, and the light color can be set freely. For example, lighting that can be set to a desired color tone by changing the color, such as switching between a light bulb color and daylight white Application to a device becomes possible.

  However, in a method of obtaining white light by mixing colors by combining LEDs of a plurality of colors, a color shift occurs with time after lighting. This is because the temperature dependency of the LED differs depending on the emission color. Generally, as the temperature rises due to energization, the LED decreases in luminous efficiency and luminance, but the luminance decreases at different rates depending on the emission color. Therefore, the optimal white light or set color at the initial setting cannot be maintained. In addition, since the deterioration rate of the LED differs depending on each emission color, the luminance decrease due to deterioration over time also varies depending on the emission color. For this reason, the optimal white light or set color at the time of initial setting cannot be maintained, and color misregistration occurs.

  Therefore, in the past, “With a simple configuration, it is possible to accurately detect uniform color mixture of three colors from the light source unit without being affected by outside light, and always optimally control the light emission color from the light source unit. It is an object of the present invention to provide a color illumination device and an emission color detection device for the color illumination device. In the light source unit 20 including the light emitting elements 21 having different emission colors and the lens 22 for controlling the light distribution of the light emitted from each light emitting element in the color lighting device 10, the light emission of each emission color. A color sensor 31 for detecting light from the element 21 is disposed, and light from the light emitting element of each emission color is guided to the color sensor 31 from within the corresponding lens by a light guide unit 32 integrated with the lens 22. The light emitting element detection device 30 of the color illumination device is configured. Is proposed (see, for example, Patent Document 1).

  Patent Document 1 states that “the light guide path 32 is formed of a translucent material so as to extend toward the center from the side surface facing the center side of each lens 22 corresponding to the LED 21 of each emission color. And preferably formed integrally with the corresponding lens 22. The ends of the light guides 32 are abutted at an angle of 120 degrees with each other at the center. Moreover, the prism part 32a inclined only 45 degree | times downward is provided. It is also disclosed.

JP 2007-257864 A (summary, pages 6-7, FIG. 2)

  In the technique described in Patent Document 1, the center of the light guide path is coincident with the center of the color sensor, and light from each light emitting color LED is guided from the lens into the light guide unit, and the prism unit. Is totally reflected and enters the color sensor. In the case of such a system, it is necessary to provide a lens and a light guide path for each of the red, blue, and green LEDs, and one for each set of modules including the red LED, the blue LED, and the green LED. Since a color sensor is required, it is not practical to use such a configuration in a high-power illumination device that uses a large number of LEDs, which leads to an increase in size, complexity, and cost of the instrument. Therefore, it is difficult to apply to a small instrument having a space limitation or an instrument using a large number of LEDs.

  The present invention has been made to solve the above-described problems, and detects the light emission intensity of a plurality of LEDs from a color sensor with a simple configuration, performs feedback control based on the detected value, and turns on the LED after lighting. An object of the present invention is to provide an LED lighting device that suppresses a color shift caused by a temperature rise and aging deterioration and keeps a light emission color constant.

An LED illumination device according to the present invention includes a plurality of LEDs having different emission colors, a substrate on which the LEDs are mounted, a light detection element that detects the light emission intensity of the LED, and an illumination device housing that houses the substrate. The light detection element is disposed on the opposite side of the surface of the substrate on which the LED is mounted, and the light receiving surface of the light detection element is formed in a direction opposite to the radiation direction of the LED, The substrate includes at least one light transmission slit formed around the installation position of the light detection element, and the lighting device housing includes the light detection element and the light transmission slit provided on the substrate. A concave recess for reflecting light is formed at the position where it is located.

According to the present invention, the substrate on which the LED is mounted is disposed on the side opposite to the surface on which the LED is mounted , and the light receiving surface of the light detection element is formed in a direction opposite to the radiation direction of the LED, The substrate includes at least one light transmission slit formed around the installation position of the light detection element, and the lighting device housing includes the light detection element and the light transmission slit provided on the substrate. Since the concave recess for reflecting light is formed at the location, the color sensor is saturated because it is not easily affected by external light and only the reflected light can enter without direct LED light entering the color sensor. This makes it possible to perform correct feedback control. In addition, since the color sensor is mounted on the same substrate as the substrate on which the LEDs are arranged, the number of components can be reduced.

It is a block diagram which shows the whole electrical structure of the LED lighting apparatus in Embodiment 1 of this invention. It is a block diagram of the LED light source part 1 of the LED lighting apparatus in Embodiment 1 of this invention. It is a block diagram of the LED light source part 1 of the LED illuminating device in Embodiment 2 of this invention. It is a block diagram of the LED light source part 1 of the LED lighting apparatus in Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing an overall electrical configuration of the LED lighting apparatus according to Embodiment 1 of the present invention.
In FIG. 1, an LED illumination device includes an LED light source unit 1, a power supply circuit 2 that drives the LED light source unit 1, a light detection unit 3 that detects light emission intensity from the LED light source unit 1, and detection signals from the light detection unit 3. And a control unit 4 that controls the output of the power supply circuit 2 to adjust the light output of the LED.

Next, the function of each part will be described.
Here, the LED light source unit 1 includes LEDs 1a, 1b, and 1c that emit light in red, blue, and green, and receives light from the power supply circuit 2 to emit light. The light detection unit 3 includes a color sensor 3a and a signal amplification circuit 3b. The color sensor 3a combines, for example, three photodiodes and a color filter that selectively transmits red, blue, and green wavelengths, thereby combining red, blue, and blue. The LED light source unit 1 detects the emission intensity of each of red, blue, and green independently. The signal amplification circuit 3b amplifies the signal from the color sensor 3a.
The color sensor 3a is a light detection element.

  The signal detected by the light detection unit 3 is input to the control unit 4 and is compared with the target signal value by the control unit 4. The control unit 4 is configured by, for example, a microcomputer, and the target signal value is output from the light detection unit 3 with predetermined signal levels of red, blue, and green LEDs, for example, so as to obtain a target emission color. Feedback control is performed so that the signal levels (light emission intensity) of red, blue, and green become the target signal levels.

  For feedback control, for example, the control unit 4 outputs PWM signals for three channels corresponding to red, blue, and green LEDs, and the power supply circuit 2 receives the PWM signal and sends the LED current corresponding to the pulse width to the LED light source unit 1. And the emission intensity of each LED is independently controlled and adjusted to the target signal level.

  In this way, the light output corresponding to each wavelength is detected by the light detection unit 3 from the LEDs of a plurality of colors, is compared with the target signal level by the control unit 4, and each color is matched with the target signal level by feedback control. Since the current supplied to the LED is adjusted, it is possible to suppress the color shift that occurs with the LED temperature rise and the aging deterioration after lighting, and to keep the emission color constant.

FIG. 2 is a configuration diagram of the LED light source unit 1 of the LED lighting apparatus according to Embodiment 1 of the present invention. FIG. 2A is a front view of the LED light source unit 1, and FIG. 2B is a cross-sectional view taken along the dashed line AA in FIG.
The LED light source unit 1 includes an LED 5, a substrate 6 on which a plurality of LEDs 5 are mounted, a lighting device housing 7 that houses the substrate 6, and a translucent cover 8 for diffusing or condensing light (FIG. 2A). (Not shown).
The LED 5 is a general shell type or surface mount type, and a multi-chip LED in which a plurality of single-color LEDs are used or a plurality of color LED chips are arranged in one package may be used. . The substrate 6 is preferably a glass epoxy resin or a metal substrate having a higher thermal conductivity, such as an aluminum substrate. A substrate 6 is attached to the illuminating device housing 7, and a metal housing with high thermal conductivity, for example, aluminum, that efficiently releases the heat generated by the LEDs 5 is desirable. Moreover, you may form the radiation fin 9. FIG.

  Here, as shown in FIG. 2B, the color sensor 3a used in the light detection unit 3 is disposed on the back surface of the substrate 6, and the light receiving surface of the color sensor 3a is attached in the direction opposite to the LED light emitting surface. A slit 11 for taking in light is provided around the substrate 6 on which the color sensor 3a is mounted. A concave recess 12 is formed in the casing 7 where the color sensor 3a is disposed and where the slit 11 is provided in order to capture light. Other portions where the LEDs 5 are arranged have a structure in which the substrate 6 and the housing 7 are in close contact with each other in order to efficiently release the heat generated from the LEDs 5 to the housing 7.

  With such a structure, most of the light output from the LED 5 is emitted to the outside through the translucent cover 8, but part of the light is reflected by the translucent cover 8 and enters the slit 11. It will be incident. The light that has entered the slit 11 is further reflected by the bottom surface of the concave recess 12 of the illumination device casing 7 and is incident on the color sensor 3a (arrow in FIG. 2).

  In general, an LED for illumination is an LED having a very high luminance level called a high-intensity LED or a power LED. If the direct light of the LED is input to the color sensor, the detection signal of the color sensor is saturated. As a result, correct measurement cannot be performed. In this method, since the color sensor 3a is disposed on the back surface of the substrate 6, only the reflected light can be input to the color sensor 3a without direct incidence of the LED 5, so that the color sensor 3a is not saturated and correct feedback control is performed. Is possible. Here, on the surface where the light of the concave depression 12 of the illumination device housing 7 is reflected, the optical design is made so that the reflected light from the LED 5 is appropriately condensed on the color sensor 3a. Further, a reflective member may be provided in the concave recess 12 and the reflected light of the LED 5 may be condensed on the color sensor 3a (not shown).

  With respect to the influence of external light, since the color sensor 3a is provided on the back surface of the substrate 6, it is difficult for external light to directly enter the color sensor 3a, and the light of the LED 5 can be detected correctly. Can be suppressed.

  As described above, the color sensor 3a is disposed on the back surface of the substrate 6 on which the LED 5 is mounted, the light intake slit 11 is provided in the substrate 6 around the color sensor 3a, and the concave recess 12 is formed in the lighting device housing 7. As a result, only the reflected light can be input without being directly influenced by the external light, and the direct light of the LED 5 does not enter the color sensor 3a, so that correct feedback control is possible without the color sensor 3a being saturated. In addition, since the color sensor 3a is mounted on the same substrate as the substrate 6 on which the LEDs 5 are arranged, the number of components can be reduced.

  Therefore, it is possible to achieve downsizing of the instrument with a simple configuration, and it is possible to apply to a small instrument with space limitations. In addition, since the emission intensity of multiple color LEDs is detected from the color sensor 3a and feedback control is performed based on the detected value, color deviation caused by LED temperature rise and aging deterioration after lighting is suppressed, and the emission color is made constant. An LED lighting device that maintains can be provided.

Embodiment 2. FIG.
FIG. 3 is a configuration diagram of the LED light source unit 1 of the LED lighting apparatus according to Embodiment 2 of the present invention. 3 (b) is a front view of the LED light source unit 1, FIG. 3 (a) is a front view of the LED light source unit 1, and FIG. 3 (b) is a cross-sectional view taken along a dashed line of FIG. 3 (a). It is arrow sectional drawing.
Note that the basic configuration and basic operation of the LED lighting device are the same as those shown in FIG. Moreover, the same code | symbol is provided to the same component.
The light source unit 1 includes an LED 5, a substrate 6 on which a plurality of LEDs 5 are mounted, an illumination device housing 7 that houses the substrate 6, and a translucent cover 8 that diffuses or collects light (in FIG. 3A). And a light-shielding socket 13 is provided at the end of the lighting device casing 7.

  The LED 5 is a general shell type or surface mount type, and a multi-chip LED in which a plurality of single-color LEDs are used or a plurality of color LED chips are arranged in one package may be used. . The substrate 6 is preferably a glass epoxy resin or a metal substrate having a higher thermal conductivity, such as an aluminum substrate. A substrate 6 is attached to the illuminating device housing 7, and a metal housing with high thermal conductivity, for example, aluminum, that efficiently releases the heat generated by the LEDs 5 is desirable. Moreover, it is good also as a fin shape. The socket 13 is made of a light-shielding material that blocks light from the outside. For example, a power connection terminal, a connector, a cord, and the like are provided to connect the substrate 6 and the power circuit 2 or connect the light source unit 1. May be used for various purposes (not shown).

Here, as shown in FIG. 3A, the color sensor 3 a used in the light detection unit 3 is provided on the substrate 6 positioned in the light-shielding socket 13 provided at the end of the lighting device housing 7. It is done. The light receiving surface of the color sensor 3 a is arranged in the same direction as the light emitting surface of the LED 5.
By adopting such a structure, most of the light output from the LED 5 is emitted to the outside through the translucent cover 8, but a part of the light is reflected by the translucent cover 8, and the illumination device It propagates through the inside of the housing 7 and enters the color sensor 3a (arrow in the figure).

  If direct light from a high-brightness LED or power LED is input to the color sensor 3a, the color sensor 3a is saturated and correct measurement cannot be performed. In this method, the light-shielding socket 13 is provided at the end of the lighting device casing 7 and the color sensor 3a is provided on the substrate 6 located inside the socket 13. Therefore, as shown in the first embodiment. Even when the color sensor 3a cannot be disposed on the back surface of the substrate, the direct light of the LED 5 does not enter the color sensor 3a, and only the reflected light of the LED 5 propagating through the inside of the illumination device housing 7 is used. Therefore, correct feedback control is possible without saturating the color sensor 3a.

  Here, in order to efficiently collect light into the color sensor 3a, the inside of the socket 13 is provided with a reflecting plate inside the socket 13, or a wall surface inside the socket 13 is subjected to a plating process or similar processing. Thus, light can be efficiently incident on the color sensor 3a (not shown). Here, the color sensor 3a is installed substantially perpendicular to the surface of the light shielding portion on which the LED of the substrate 6 is mounted, and the light receiving surface of the color sensor 3a is directed to the inside of the instrument as shown in FIG. You may install toward (LED side). Further, when constructing a long lighting device, as shown in the figure, a socket 13 and a color sensor 3a having light shielding properties may be provided on both the left and right sides, and feedback control may be performed independently on the left and right sides, for example.

  Since the socket 13 provided at the end of the illumination device has a light shielding property against external light, the external light is difficult to directly enter the color sensor 3a, and feedback control is performed in order to correctly detect the light of the LED 5. Malfunctions can be suppressed.

  Further, as shown in FIG. 3D, the color sensor 3a is provided at a position where the light receiving surface faces in the direction facing the substrate 6 in the socket 13, that is, the LED mounting surface is received so that the LED mounting surface faces the upward substrate 6. If the color sensor 3a is provided on the ceiling surface of the socket 13 with the surface facing downward, the color sensor 3a has a light-receiving surface facing in a direction opposite to the direction in which the external light is incident, so that it is more difficult for external light to enter. Can be built. At this time, detection signals from the color sensor 3a can be easily connected to the substrate 6 by using the flexible substrate 14 made of a flexible material.

  As described above, since the light-shielding socket 13 is provided at the end of the lighting device casing 7 and the color sensor 3a used for the light detection unit 3 is provided inside the socket 13, as described in the first embodiment. Even when the color sensor 3a cannot be arranged on the back surface of the substrate 6, it is difficult to be affected by external light, the direct light of the LED 5 is not easily incident on the color sensor 3a, and only reflected light can be incident. Correct feedback control is possible without saturation of the color sensor 3a. Since the color sensor 3a is mounted on the same substrate as the substrate 6, the number of components can be reduced.

  Accordingly, it is possible to achieve downsizing of the appliance with a simple configuration, and it can be applied to a small appliance having a space limitation, for example, a line-shaped lighting fixture, and detects the emission intensity of a plurality of color LEDs from the color sensor 3a. Since the feedback control is performed based on the detected value, it is possible to provide an LED lighting device that suppresses a color shift caused by an increase in LED temperature after lighting and aged deterioration and keeps the emission color constant.

Embodiment 3 FIG.
FIG. 4 is a configuration diagram of the LED light source unit 1 of the LED lighting apparatus according to Embodiment 3 of the present invention. FIG. 4A is a front view of the LED light source unit 1, and FIG. 4B is a cross-sectional view taken along a dashed line CC in FIG. 4A. Note that the basic configuration and basic operation of the LED lighting device are the same as those shown in FIG. Moreover, the same code | symbol is provided to the same component. The light source unit 1 includes an LED 5, a substrate 6 on which a plurality of LEDs 5 are mounted, an illumination device housing 7 that houses the substrate 6, and a translucent cover 8 that diffuses or collects light (in FIG. 4A). (Not shown). In FIG. 4A, a part of the lighting device casing 7 (reflector 7a) is not shown.

  The LED 5 is a general shell type or surface mount type, and a multi-chip LED in which a plurality of single-color LEDs are used or a plurality of color LED chips are arranged in one package may be used. . The substrate 6 is preferably a glass epoxy resin or a metal substrate having a higher thermal conductivity, such as an aluminum substrate. A substrate 6 is attached to the illuminating device housing 7, and a metal housing with high thermal conductivity, for example, aluminum, that efficiently releases the heat generated by the LED is desirable. Moreover, you may form the radiation fin 9. FIG.

The color sensor 3 a used for the light detection unit 3 is arranged along the outer periphery of the circular substrate 6. This is because, for example, in a large luminaire having a wide light emitting surface, it is difficult to perform feedback control with only one color sensor 3a. Therefore, for example, the light emitting surface is divided into a plurality of areas, and the color sensor 3a for each area. Is provided to perform feedback control independently for each area. Therefore, in this embodiment, four color sensors 3 a are provided on the outer periphery of the substrate 6. And the illuminating device housing | casing 7 is made into the shape 7b which covers the light-receiving surface of the color sensor 3a provided in the outer periphery of the board | substrate 6. FIG.
With such a structure, most of the light output from the LED 5 is emitted to the outside through the translucent cover 8, but a part of the light is reflected by the translucent cover 8 and the illumination device housing. It propagates inside the body 7 and enters the color sensor 3a. Here, you may install the light-receiving surface of the color sensor 3a toward the inner side direction of an instrument as shown in FIG.4 (c).

  If direct light from a high-brightness LED or power LED is input to the color sensor 3a, the color sensor 3a is saturated and correct measurement cannot be performed. In this method, light output from the LED 5 is transmitted through the translucent cover 8 and Since only the reflected light can propagate without propagating through the interior of the illumination device housing 7 and the direct light of the LED 5 does not enter the color sensor 3a, correct feedback control is possible without the color sensor 3a being saturated. Here, since the inside of the shape 7b that covers the color sensor 3a of the illuminating device casing 7 is a surface on which the light of the LED 5 is reflected, a light can be efficiently incident on the color sensor 3a by providing a reflector. (Not shown).

  In addition, for external light, the shape 7b that covers the color sensor 3a of the lighting device housing 7 is configured so that the external light is not directly incident on the color sensor 3a. Can do.

  As shown in FIG. 4D, if the color sensor 3a is provided at a position facing the substrate 6, the color sensor 3a faces the light receiving surface in a direction opposite to the direction in which the external light is incident. A structure resistant to light can be constructed. At this time, the detection signal extraction from the color sensor 3a can be easily connected to the substrate 6 by using the flexible substrate 14 or the like.

  As described above, the color sensor 3 a is arranged along the outer periphery of the circular substrate 6, and the lighting device housing 7 has a shape 7 b that covers the color sensor 3 a provided on the outer periphery of the substrate 6. In a large large instrument, for example, even when a plurality of color sensors 3a are arranged and a plurality of areas are independently subjected to feedback control, it is difficult to be influenced by external light and only reflected light can be input to the color sensor 3a. Correct feedback control is possible without saturation of the color sensor 3a. In addition, since the color sensor 3a can be mounted on the same substrate as the substrate 6 on which the LEDs 5 are mounted, the number of components can be reduced.

  Therefore, it is possible to reduce the number of parts with a simple configuration, achieve downsizing and weight reduction of the appliance, detect the emission intensity of multiple color LEDs from the color sensor, perform feedback control based on the detected value, and change the temperature after lighting It is possible to provide an LED lighting device that suppresses color misregistration caused by rising and aging deterioration and keeps the emission color constant.

  DESCRIPTION OF SYMBOLS 1 LED light source part, 2 Power supply circuit, 3 Light detection part, 3a Color sensor, 4 Control part, 5 LED, 6 Board | substrate, 7 Illuminating device housing | casing, 7a Reflector, 8 Translucent cover, 9 Radiation fin, 11 Slit, 12 concave depression, 13 light shielding socket, 14 flexible substrate.

Claims (3)

A plurality of LEDs having different emission colors, a substrate on which the LEDs are mounted, a light detection element for detecting the light emission intensity of the LED, and a lighting device housing for storing the substrate,
The light detection element is disposed on the opposite side of the surface of the substrate on which the LED is mounted, and the light receiving surface of the light detection element is formed in a direction opposite to the emission direction of the LED,
The substrate includes at least one light transmission slit formed around the installation position of the light detection element,
The lighting device housing, the location where the light detecting element and the light transmissive slits provided in the substrate is positioned, LED lighting device characterized by depression of the concave for light reflection is formed.   The LED lighting device according to claim 1, wherein a light reflecting plate is provided between the light reflecting concave depression, the light detecting element, and the light transmitting slit. A power supply circuit for supplying a driving current to the LED;
A control unit for controlling the drive current,
The light detection element detects the emission intensity of each emission color of the LED,
Wherein, based on a detection signal of the light detecting element, according to claim 1 or claim light output of each light emitting color of the LED is characterized in that for controlling the drive current to a predetermined state 2. The LED lighting device according to 2.

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