JP2010192582A - Led light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique capable of providing multiple types of functions without increasing the size of a device, and providing high emission quality, in a light-emitting device using an LED as a light-emitting source. <P>SOLUTION: In this light-emitting device, on the backside (lower side) of a circuit board with a first light-emitting element arranged thereon, a second light-emitting element that emits a color different from that of the first light-emitting element is arranged. An opening is formed on the circuit board, and a concave reflecting mirror for reflecting light emitted from the second light-emitting element and guiding the reflected light from the opening to the first light-emitting element side is arranged on the lowest layer of an LED package. The light-emitting device includes a control part capable of driving the first light-emitting element and the second light-emitting element independently of each other. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to miniaturization and high performance of a light emitting device using an LED as a light emitting source. In particular, the present invention relates to a technology for reducing the size and improving the performance of a light-emitting device mounted on a small photographing device such as a thin digital camera or a mobile phone with a photographing function.

  An imaging device such as a digital camera is provided with a light emitting device such as a strobe. FIG. 10 shows an LED strobe 1 that emits light using an LED in such a light emitting device. 10A is a front view of the LED strobe 1 and FIG. 10B is a cross-sectional view in the direction of the arrow A-A ′. As shown in the figure, an LED strobe 1 includes an LED 3 as a light source disposed on a substrate 2, a reflector (hereinafter referred to as a reflector) 4 installed on the outer periphery of the LED 3, a lens 5, and a reflector 4. And a lens holding part 6 that holds the lens 5. A light beam emitted from the LED 3 may directly reach the lens 5, or may be reflected by the reflector 4 or the substrate 2 and reach the lens 5. The lens 5 controls these two types of light and irradiates the target range with strobe light (see, for example, Patent Document 1).

  In general, in addition to the LED strobe 1, the photographing device is provided with a light emitting device such as an indicator. The indicator is used to clarify the remaining time display and focus position of the self-timer. FIG. 11 shows an LED strobe 1 ′ with an indicator in which an indicator is incorporated in the LED strobe 1. 11A is a front view, and FIG. 11B is a cross-sectional view in the direction of arrow B-B ′. As shown in the drawing, the indicator-equipped LED strobe 1 ′ further includes an indicator LED 7 on the substrate 2 of the LED strobe 1 (see, for example, Patent Document 2).

Japanese translation of PCT publication No. 2004-507038 JP-A-2005-301121

  Recently, digital cameras and mobile phones with photographing functions are becoming thinner and smaller, and light-emitting devices mounted thereon are also demanded to be thinner and smaller. On the other hand, the required light emission functions include not only the strobe function but also various indicators functions. However, as in the configuration of the LED strobe 1 'with an indicator described above, a separate light source is required for each function, and the entire light emitting device is correspondingly enlarged and the occupied volume is increased. Therefore, not only the demands for multi-functionality, thinness, and miniaturization are not satisfied, but also the wiring of the drive circuit is complicated, the number of parts is increased, the product cost is increased, and the assembly man-hours during production are increased. Yes.

  In addition, the size of the light emitting device is required to be thin and small, but a large amount of light is required and the light emitting source is large, and thus color unevenness is likely to occur. For example, an LED that emits white light used in an LED strobe 1 or the like generally emits fluorescence of other colors (red component and green component) by receiving blue light emitted from the blue light emitting device. The phosphor to be applied is configured. With the demand for miniaturization and thinning, the distance between the LED 3 and the lens 5 is closer, and the phosphor surface of the LED 3 is relatively larger than the size of the lens 5. For this reason, in the optical system of the LED strobe 1, the LED 3 needs to be handled as a surface light source instead of a point light source.

  However, in general, in an LED using a blue light emitting element, the color temperature increases and becomes bluish at the center of the irradiation surface, whereas the color temperature decreases and yellowish at the periphery of the irradiation surface. As shown in FIG. 12, the light beam generated from the LED 3 treated as a surface light source becomes yellowish from white as the generation position approaches the end face of the phosphor. Therefore, the difference in color is emphasized by the lens 5. Color unevenness occurs on the irradiated surface. In FIG. 12, 8 is an irradiated surface, 9 is a color unevenness generation region, and 10 is a white region.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technology for realizing various light emitting functions with high irradiation quality without increasing the size of a light emitting device using an LED as a light source. To do.

  The present invention includes light emitting elements of two different emission colors that can be controlled independently, and distributes light from one light emitting element so as to improve the irradiation quality of light from the other light emitting element.

  Specifically, a substrate, a first light emitting element disposed on the substrate, a second light emitting element disposed on a surface of the substrate opposite to the first light emitting element, and the first light emitting element. A first optical system that controls a radiation direction of light emitted from one light-emitting element; and a second optical system that controls a radiation direction of light emitted from the second light-emitting element; The second optical system is configured to control so that light emitted from the second light-emitting element passes through the opening and is guided to the first optical system. An LED light-emitting device is provided.

  According to the present invention, in a light emitting device using an LED as a light source, various light emitting functions can be realized and the quality of irradiation can be improved without increasing the size of the device.

(A) is a schematic front view of the light-emitting device of embodiment of this invention, (b) is a schematic sectional drawing of the light-emitting device. (A) is a schematic front view of LED of embodiment of this invention, (b) is a schematic sectional drawing of the LED. It is a figure for demonstrating the light beam path | route (optical path) of LED of embodiment of this invention. (A) is a figure for demonstrating an electric current waveform at the time of the strobe light emission of embodiment of this invention, and (b) at the time of illumination, respectively. (A) is a figure for demonstrating each current waveform at the time of the flashing indicator light emission of embodiment of this invention, (b) at the time of lighting indicator light emission, respectively. (A), (b) is a figure for demonstrating the other example of a current waveform of embodiment of this invention. (A)-(c) is a figure for demonstrating the other example of the opening part of LED of embodiment of this invention. (A)-(c) is a figure for demonstrating the other example of the shape of the reflective mirror of LED of embodiment of this invention. It is a figure for demonstrating the light beam path | route (optical path) of LED of embodiment of this invention. (A) is a front view of a conventional LED strobe, and (b) is a sectional view of the same. (A) is a front view of the LED strobe with a conventional indicator, (b) is the same sectional view. It is a figure for demonstrating generation | occurrence | production of the color nonuniformity in the conventional LED flash.

<< First Embodiment >>
Hereinafter, a first embodiment to which the present invention is applied will be described. Hereinafter, in all the drawings for explaining the embodiments of the present invention, those having the same function are denoted by the same reference numerals, and repeated explanation thereof is omitted.

  A schematic configuration of the light emitting device 100 of the present embodiment will be described. Fig.1 (a) is a schematic front view of the light-emitting device 100 of this embodiment. 1B is a schematic cross-sectional view of the light emitting device 100 in the direction of arrows AA. As shown in these drawings, the light emitting device 100 of the present embodiment basically has the same configuration as the conventional light emitting device shown in FIG. 10, and includes a substrate 200, an LED 300 disposed on the substrate 200, The reflector 400 provided in the outer periphery of LED300, the lens 500, and the lens holding part 600 which is comprised integrally with the reflector 400 and hold | maintains the lens 500 are provided.

  The LED 300 of the present embodiment includes a light emitting element having two different emission colors that can be independently controlled for light emission. Hereinafter, the configuration of the LED 300 will be described. Fig.2 (a) is a schematic front view of LED300 of this embodiment, FIG.2 (b) is a BB arrow schematic sectional drawing of LED300 of this embodiment. Moreover, FIG. 3 is a figure for demonstrating the light beam path | route (optical path) of LED300 of this embodiment.

  As shown in FIG. 2, the LED 300 according to the present embodiment includes an LED inner substrate 310, a blue light emitting element 320 that is a light source disposed on the LED inner substrate 310, and a side opposite to the blue light emitting element 320 of the LED inner substrate 310. A red light emitting element 330 disposed on the surface of the LED, a first LED package 340 formed on the blue light emitting element 320 side of the LED substrate 310, and a blue light emitting element 320 side of the first LED package 340. The in-LED reflector 350, a phosphor coating region 360 that contains a phosphor and is formed so as to cover the blue light emitting element 320, and the second LED package 370 that is formed on the red light emitting element 330 side of the in-LED substrate 310. And a reflecting mirror 380 having a concave optical surface formed on the red light emitting element 330 side of the second LED package 370. A first optical system is configured by the in-LED reflector 350 on the blue light emitting element 320 side of the in-LED substrate 310. Further, on the red light emitting element 330 side of the substrate 310, the reflecting mirror 380 forms a second optical system.

  The phosphor coating region 360 is made of a resin that absorbs blue light and emits yellow fluorescence, for example, containing a YAG phosphor. In addition, in LED300 of this embodiment, the number of each of the blue light emitting element 320 and the red light emitting element 330 is not ask | required. Here, as an example, a case where four blue light emitting elements 320 and one red light emitting element 330 are provided is illustrated.

  The LED inner substrate 310 of the present embodiment includes drive circuits (not shown) that cause the blue light emitting element 320 and the red light emitting element 330 to emit light. The drive circuit of the present embodiment supplies current according to a control signal received via the substrate 200, and drives each of the blue light emitting element 320 and the red light emitting element 330 independently. In the present embodiment, the LED inner substrate 310 and the substrate 200 are configured such that an electrode (not shown) disposed on the bottom surface of the LED 300 package and the substrate 200 are arranged via a wiring pattern in the LED 300 package including wire bonding. It is connected by soldering.

  Moreover, in order to guide the light emitted from the red light emitting element 330 to the blue light emitting element 320 side, the LED inner substrate 310 of the present embodiment includes one or more openings 390 in the periphery thereof. As shown in FIG. 2, in the present embodiment, the opening 390 is formed in the peripheral portion surrounding the four blue light emitting elements.

  A part of the light emitted from the blue light emitting element 320 is absorbed by the phosphor coating region 360, and yellow fluorescence is emitted. Yellow light and blue light are mixed to be converted into white light, and as shown by a solid line in FIG. 3, the light passes through the first optical system on the blue light emitting element 320 side as usual and is emitted upward. On the other hand, the light emitted from the red light emitting element 330 is reflected by the reflecting mirror 380 in the second optical system on the red light emitting element 330 side and is provided in the substrate 310, as indicated by a broken line in FIG. The light passes through the portion 390 and is guided to the blue light emitting element 320 side.

  White light obtained by the light emitted from the blue light emitting element 320 and the phosphor in the phosphor coating region 360 has a yellow color due to a lower color temperature at the periphery of the irradiated surface than at the center of the irradiated surface. Therefore, the color temperature distribution on the irradiated surface is not uniform, and color unevenness occurs. In the present embodiment, the light from the red light emitting element 330 is distributed so that white light with a bluish color at the center of the irradiation surface can be corrected to a yellowish color similar to the surroundings, Improve color unevenness.

  Specifically, the position of the opening 390 and the shape of the second optical system (reflecting mirror 380) of the present embodiment is such that the light from the red light emitting element 330 has a high color temperature from the central part of the irradiation surface to the peripheral part. Adjust so that light is distributed in a stepwise manner to the bluish central area. Thereby, the light from the red light emitting element 330 passes through the opening 390 and is superimposed on the bluish light flux at the center of the irradiation surface. As a result, the bluish white light at the center of the irradiated surface is corrected to a yellowish color like the peripheral portion, and the color temperature and color unevenness of the entire irradiated surface can be improved.

  The LED 300 according to the present embodiment has the above-described configuration, and can realize light emission of, for example, strobe light emission, illumination, blinking indicator, and lighting indicator by driving current obtained via the substrate 200. Examples of current waveforms for driving the blue light emitting element 320 and the red light emitting element 330 in order to realize strobe light emission, illumination, blinking indicator, and lighting indicator are shown in FIGS. 4, 5, and 6.

  FIG. 4A is a diagram showing an example of a current waveform that realizes strobe light emission. Here, a current is supplied so that only the blue light emitting element 320 is driven with a large amount of current for a short time. Thereby, white light in which blue light and yellow fluorescence are mixed is emitted with a large amount of light, and strobe light emission can be realized.

  FIG. 4B is a diagram illustrating an example of a current waveform that realizes light emission as illumination. Here, a current is supplied so that the blue light emitting element 320 and the red light emitting element 330 are simultaneously turned on according to an on instruction from the user and turned off according to an off instruction. Thereby, white light and red light are mixed and light with improved color unevenness at the center of the irradiated surface is emitted, and high-quality illumination can be realized. Note that when light is emitted as illumination, the light is driven with a smaller amount of current compared to the case of strobe light emission.

  FIG. 5A is a diagram illustrating an example of a current waveform that realizes light emission as a blinking indicator. Here, only the red light emitting element 330 is supplied with current so as to emit light intermittently. FIG. 5B is a diagram illustrating an example of a current waveform that realizes light emission as a lighting indicator. Here, a current is supplied so that only the red light emitting element 330 emits light continuously during a predetermined lighting period. As a result, it is possible to realize a desired indicator function in which red light blinks and lights up. Note that when the light is emitted as the indicator, the light is driven with a smaller amount of current than when the strobe light is emitted.

  In addition, when realizing blinking or lighting as an indicator, the light emitting element that is driven to emit light is not limited to the red light emitting element 330 as described above. For example, as shown in FIG. 6A, a current may be supplied so that the blue light emitting element 320 and the red light emitting element 330 emit light simultaneously. Here, as an example, a case where the amount of current supplied to each of the blue light emitting element 320 and the red light emitting element 330 is changed for each light emission is shown. The amount of current to be supplied is not limited to this. Thereby, blinking or lighting of a mixed color of white light and red light can be obtained.

  Further, as shown in FIG. 6B, the amount of current for driving the blue light emitting element 320 and the amount of current for driving the red light emitting element 330 during each light emission may be changed during the supply period. Here, as an example, a case where the amount of current supplied to the blue light emitting element 320 and the red light emitting element 330 is changed in reverse is shown. The way of change is not limited to this. By controlling in this way, the color of the flashing light can be changed.

  As described above, the LED 300 according to the present embodiment includes two types of light-emitting elements that can be controlled independently, and is configured to reduce color unevenness on the irradiation surface when the light is emitted simultaneously. Yes. For this reason, the light emitting device 100 according to this embodiment equipped with the LED 300 can realize various functions such as a strobe, an indicator, and illumination with high quality with one light source. Further, the control can be easily realized only by changing the amount of current supplied to the LED. Therefore, according to this embodiment, since it is not necessary to provide a plurality of light emitting sources in order to realize a large number of light emitting functions, a high performance LED light emitting device that is multifunctional and has little color unevenness without increasing the size of the device. Can be realized.

  In the above embodiment, the case where the opening 390 is provided in the peripheral portion of the substrate 310 has been described as an example. However, the arrangement position of the opening 390 is not limited to this. It is sufficient that the light from the red light emitting element 330 can be distributed to the first optical system at a desired position and with a desired intensity. For example, as shown in FIGS. 7A and 7B, the substrate 310 may be provided with a plurality of elongated openings 390 'in a cross shape. Here, a case will be described as an example where each blue light emitting element 320 is configured to be covered with a phosphor independently and an opening 390 ′ is provided between each of the four blue light emitting elements 320. FIG. 7C shows an optical path of the LED 300 ′ according to this modification.

  In the case of the LED 300 ′ of the modification shown in FIG. 7, the arrangement of the opening 390 and the second optical element so as to distribute the light from the red light emitting element 330 stepwise from the center of the irradiation surface toward the periphery of the irradiation surface. The system (the shape of the reflecting mirror 380) is adjusted. As shown in FIG. 7C, the light from the red light emitting element 330 passes through the opening 390 'and is superimposed on the bluish light flux at the center of the irradiation surface. For this reason, the blueness of the irradiated surface can be appropriately suppressed, and color unevenness can be corrected over the entire irradiated surface. Accordingly, when used as illumination as described above, illumination with little color unevenness can be realized. That is, according to this modification, it is possible to realize a high-performance LED lighting device that is multifunctional and has little color unevenness without increasing the size of the device.

  Further, the shape of the reflecting mirror 380 is not limited to the concave shape described above. The light from the red light emitting element 330 may be distributed to the first optical system at a desired intensity and angle. For example, the light has a shape as shown in FIGS. 8 (a), 8 (b), and 8 (c). Also good. In particular, as shown in FIG. 8A, in the configuration having the convex portion 700 on the concave surface of the reflecting mirror 380, more light from the red light emitting element 330 is emitted to the central portion of the irradiation surface than in the configuration having no convex portion. Light distribution is possible and color unevenness is further improved.

  When the shape of the reflecting mirror 380 is concave like the reflecting mirror 380 of the present embodiment shown in FIG. 3, the angle formed with the exit surface of the light emitted from the red light emitting element 330 is close to a right angle as shown in FIG. 9. The light (light traveling directly below) hits the LED inner substrate 310 and does not pass through the opening 390. Moreover, it is also oriented in the vicinity of the periphery of the irradiated surface with relatively little bluishness. On the other hand, as shown in FIG. 8A, when a convex portion 700, which is a convex raised region, is provided in a region (immediately lower) of the concave surface of the reflecting mirror 380 facing the emission surface of the red light emitting element 330. The light reflected in the vicinity immediately below the red light emitting element 330 gathers in the vicinity of the end of the reflecting mirror 380, is reflected here, passes through the opening 390, and is emitted to the center of the irradiation surface. As described above, when the convex portion 700 is provided in the reflecting mirror 380, more light rays are emitted from the opening 390 than in the case where the convex region 700 is not provided, and the utilization efficiency of the red light emitting element 330 is increased. Furthermore, since the light emitted to the periphery of the irradiated surface is reduced, the color unevenness of the entire irradiated surface is further improved. In addition, the convex part 700 does not need to be a pointed shape, and may be round or flat.

  Furthermore, the installation position and the number of installations of the red light emitting elements 330 can be selected as appropriate. Moreover, the light emitting element arrange | positioned on the opposite side to the blue light emitting element 320 arrangement | positioning side of the board | substrate 310 is not restricted to red. For example, an orange or yellow light emitting element (LED) may be used. As described above, various functions can be realized, and white light obtained by the blue light emitting element and the phosphor is mixed with color, thereby causing uneven color. Any light-emitting element that emits light of a color capable of reducing the above may be used.

  In addition, the light emitting device 100 of the present embodiment may be configured to include a control unit (not shown) that controls the amount of current supplied to the drive circuit. The control unit, for example, previously stores driving current waveforms such as strobe light emission, blinking indicator, lighting indicator, and illumination as a program, and receives an instruction (control signal) from an imaging device on which the light emitting device 100 is mounted or from a user. In response to the instruction, the drive circuit is driven according to the program, and the light emission timing and the current amount of each of the blue light emitting element 320 and the red light emitting element 330 are controlled. In particular, the color unevenness at the time of illumination can be corrected with higher accuracy by controlling the amount of current supplied to the light emitting elements by the control unit.

1: LED strobe, 1 ′: LED strobe with indicator, 2: substrate, 3: LED, 4: reflector, 5: lens, 6: lens holding section, 7: indicator LED, 8: projection surface, 9: color unevenness Generation region, 10: white region, 100: light emitting device, 200: substrate, 300: LED, 300 ′: LED, 310: substrate in LED, 320: blue light emitting device, 330: red light emitting device, 340: first LED Package, 350: Reflector in LED, 360: Phosphor coating area, 370: Second LED package, 380: Reflector, 390 ′: Opening, 390: Opening, 400: Reflector, 500: Lens, 600: Lens Holding part, 700: convex part

Claims (8)

A substrate,
A first light emitting element disposed on the substrate;
A second light emitting element disposed on a surface of the substrate opposite to the first light emitting element;
A first optical system that controls a radiation direction of light emitted by the first light emitting element;
A second optical system that controls the radiation direction of the light emitted by the second light emitting element,
The substrate comprises one or more openings,
The LED light-emitting device, wherein the second optical system is formed so that light emitted from the second light-emitting element passes through the opening and is guided to the first optical system. The LED light-emitting device according to claim 1,
The one or more openings are formed in a peripheral portion surrounding the first light emitting element. The LED light-emitting device according to claim 1,
The one or more openings are formed between the first light emitting elements. The LED light emitting device. The LED light-emitting device according to any one of claims 1 to 3,
The first light emitting element is a blue light emitting element,
An LED light-emitting device, further comprising a phosphor coating region formed so as to cover the blue light-emitting element. The LED light-emitting device according to claim 1,
The LED light emitting device, wherein the second light emitting element is a red light emitting element. The LED light-emitting device according to claim 1,
The second optical system includes a concave reflecting mirror. The LED light-emitting device according to claim 1,
The LED light emitting device, wherein the second optical system includes a concave reflecting mirror having a convex portion in the vicinity immediately below the second light emitting element. The LED issuing device according to any one of claims 1 to 7,
Control means for controlling the driving of the first light emitting element and the second light emitting element, respectively,
The control means includes
Strobe light emission control means for controlling the first light emitting element to emit light at a predetermined intensity for a predetermined time;
Indicator blinking control means for controlling the first light emitting element and the second light emitting element to emit light at a predetermined intensity at a predetermined time interval substantially simultaneously;
Indicator lighting control means for controlling the second light emitting element to emit light at a predetermined intensity for a predetermined time; and
Illumination control means for controlling the first light emitting element and the second light emitting element to emit light at a predetermined intensity for a predetermined time substantially simultaneously, and
In accordance with a control signal from the outside of the LED light emitting device, the control means is one of the control means of the strobe light emission control means, the indicator blinking control means, the indicator lighting control means, and the illumination control means. An LED light-emitting device that controls driving of the first light-emitting element and the second light-emitting element.

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