JP2006107850A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a planer lighting device which can illuminate not only a partial area but a wide area such as a room even with light emitting elements by utilizing light of the emitting elements effectively. <P>SOLUTION: A plurality of light emitting elements 1 of a reflection type and a chip type are arranged in a matrix shape and mounted on a surface of an insulating substrate 2 having electrode wiring everywhere on the surface so as to be connected to the electrode wiring, where the plurality of the light emitting elements 1 are connected to each other in series and/or parallel with not shown electrode wiring. A light dispersion plate 3 is formed on the light emitting side of the chip type light emitting elements 1 through a fixed spacing d from the chip type light emitting elements 1, and a heat sink 4 is formed on the other side of the insulating substrate 2 so as for an air layer not to exist between them. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lighting device using a light emitting element. More specifically, the present invention relates to an illuminating apparatus using a high-output light emitting element that can replace an illuminating apparatus that conventionally illuminates a wide range by arranging a number of long fluorescent tubes.

In recent years, with the advent of blue light emitting diodes (LEDs), LEDs have been used as light sources for displays and signal devices, and LEDs have been used in place of electric lights. When an LED is used instead of this electric lamp, for example, as shown in FIG. 3, a plurality of lamp-type (so-called bullet-type) LEDs 96 are arranged on a disk-like substrate 95 and connected in series and parallel, and the surface A milky white translucent cover 94 is placed on the side, and the wiring of the connected LED 96 is connected to a socket 92. And what is made into the illuminating device which can be used instead of a normal electric light by connecting alternating current power supply to the socket 92 is known (for example, refer patent document 1).
Japanese Patent Laid-Open No. 10-083701

  As described above, when many lamp-type (dome-shaped) LEDs are bundled to form a light bulb, the directivity characteristics of the LEDs are very narrow, and thus very strong light is emitted to the top side of the dome-shaped cover. The light emitted in the lateral direction becomes very weak. For example, when this lighting device is mounted on the ceiling, the corner of the room is dark even though it is bright underneath the lighting device. In some cases, it is not always suitable.

  On the other hand, instead of lamp-type light-emitting elements, LED chips are arranged vertically and horizontally, or a plurality of light-emitting portions are formed on a large substrate such as a semiconductor wafer at regular intervals so as to emit light without directivity over a wide area. Even if an attempt is made to configure the lighting device, the light traveling in the lateral direction is attenuated by absorption between adjacent LED chips or light emitting parts, or is not contributed to the irradiation on the front side, and is wasted. Since the light irradiation on the front side is originally weak, the luminance on the front side is not sufficiently increased.

  The present invention has been made to solve such problems, and by using the light effectively while using the light emitting element, it illuminates a wide area such as a room very brightly rather than partially. An object of the present invention is to provide an illuminating device that can be used.

  Another object of the present invention is to increase the luminance of the illumination, so that even if the heat generation of the light emitting element is increased, a structure that can quickly dissipate the heat, so that the problem of heat generation can be solved. To provide an apparatus.

  An illuminating device according to the present invention is mounted in a matrix so as to be connected to the electrode wiring on one surface of the insulating substrate, and the electrode wiring is formed on one surface of the lighting device. A plurality of reflective chip light emitting elements connected to the light emitting plate, a light diffusing plate provided on the light emitting surface side of the chip light emitting element at a predetermined interval from the chip light emitting element, and the insulating substrate And a heat radiating plate provided on the surface side so as not to interpose an air layer.

  Here, the reflective chip type light emitting element is a light emitting element chip mounted so that the pair of electrode terminals and both electrodes are connected to the surface of an insulating substrate provided with a pair of electrode terminals at both ends. It means a light emitting device having a structure in which a reflecting wall is provided on the outer periphery and light is not emitted beside it.

  The surface of the light diffusing plate facing the light emitting element chip is embossed, thereby reducing the distance between the light emitting element and the light diffusing plate and minimizing the attenuation of the light emitted. The non-light emitting area of the interval can be made inconspicuous.

  By further dissipating heat on the surface opposite to the surface on which the insulating substrate of the heat sink is provided, heat dissipation can be further promoted. Even if it is used, it is possible to eliminate the influence of heat generation on the light emitting element and the safety problem against fire.

  The directivity of the reflective chip light emitting element is 120 ° ± 20 ° in an angle where the output is halved, which reduces the distance between the light emitting element and the light diffusion plate to about 30 mm. However, the light can be made uniform, and the light can be extracted most effectively from the light diffusing plate.

  According to the present invention, since the reflective chip-type light emitting elements are arranged in a matrix, the light emitted from each light emitting element does not go sideways, but the light emission pattern in which the light travels obliquely forward with the front as the center. Become. For this reason, light travels relatively far and light travels in an oblique lateral direction, but light does not travel directly to the side, so light absorption or blocking is hardly caused between adjacent light emitting elements. In addition, since the light diffusing plate is provided at a certain interval on the light emitting surface side, the gap is hardly noticeable even if the light emitting elements are arranged at a predetermined interval. As a result, the light emitted from each light-emitting element can be used without waste, and the light-emitting element spacing is inconspicuous, and the indirect light illumination device has a uniform brightness over a very wide range. be able to.

  Further, for example, by forming the reflective wall of the reflective chip light emitting element so that the directivity characteristic of the light emitting element is about 120 ° ± 20 °, the distance between the light emitting element and the light diffusion plate is about 30 mm, When the arrangement interval of the light emitting elements is set to about 1 mm (the LED chip interval is slightly less than 3 to 4 mm), the portion weakened by the spread of light is compensated on the light diffusion plate by the adjacent light emitting elements, and the distance between the light emitting elements Even if a light diffusing plate having a high transmittance of about 90% is used, uniform light emission is achieved in the plane. As the distance between the light emitting element and the light diffusing plate increases, the space for installing the lighting device increases, which is inconvenient, and light is attenuated while being diffusely reflected in the space between them. In the present invention, by using a reflective chip type light emitting element and a light diffusing plate, this interval can be made very small, the installation space can be made very small, Brightness can be increased.

  For example, in a general lamp type light emitting device as shown in FIG. 3, the directivity characteristic is about 20 ° to 70 °, for example, so that the interval is set to, for example, about 60 mm or more and irregular reflection is performed inside. Otherwise, a uniform light emitting surface cannot be obtained within the surface, so that a large installation space is required, and a large amount of light is lost due to irregular reflection, resulting in a decrease in room brightness for the same input. Further, in the present invention, since the insulating substrate for mounting the light emitting element is attached to the heat radiating plate with, for example, a heat conductive adhesive so as not to interpose an air layer, the light emitting elements are arranged in a matrix at very narrow intervals. Even if heat is generated by mounting a lot and continuously operating all instead of a pulse operation at the same time, heat can be efficiently dissipated through the heat sink. By providing heat radiating means such as heat radiating fins and water-cooled tubes on the rear surface of the heat radiating plate, heat can be radiated more efficiently, and the problems of reliability of the light emitting element and maintenance of the lighting device can be solved. .

  In addition, the surface of the light diffusing plate facing the light emitting element can be textured to randomize the light traveling direction, so that light emission can be achieved even when the distance between the light emitting element and the light diffusing plate is reduced. It is more preferable because the dead space between the elements can be made inconspicuous.

  Next, the illumination device of the present invention will be described with reference to the drawings. The lighting device according to the present invention is shown in FIG. 1A as a cross-sectional explanatory view of one embodiment, and FIG. 1B as a plan explanatory view of an insulating substrate provided with a light emitting element, respectively. A plurality of reflective chip-type light emitting elements 1 are mounted in a matrix so as to be connected to the electrode wiring on one surface of the insulating substrate 2 on which electrode wiring (not shown) is formed on one surface. The light emitting elements 1 are connected in series and / or in parallel by electrode wiring (not shown). A light diffusing plate 3 is provided on the light emitting surface side of the chip type light emitting device 1 with a fixed distance d from the chip type light emitting device 1, and a heat sink 4 is not shown on the other surface side of the insulating substrate 2. The air layer is provided so as not to be interposed via a conductive adhesive or the like.

  In the example shown in FIG. 1A, the lighting device of the present invention is directly attached to the ceiling or the like, and the light diffusing plate 3 is fixed to the top plate 7 or the like with screws not shown. Then, the insulating substrate 2 is fixed to the beam 9 or the like via the mounting plate 8 or the like so that the distance d between the light diffusion plate 3 and the light emitting element 1 is a constant distance d. However, the insulating substrate 2 and the light diffusing plate 3 are fixed to a box or a frame so that the distance d between the light emitting element 1 and the light diffusing plate 3 is a constant distance, and the box or the like is fixed. You may make it the structure attached to desired places, such as a ceiling. However, it is preferable to attach the insulating substrate 2 via the mounting plate 8 or the like because the heat dissipation characteristics are improved. From this point of view, the mounting plate 8 is preferably a metal plate having good thermal conductivity and high mechanical strength, and aluminum, stainless steel, iron, or the like is used. The connection between the mounting plate 8 and the heat radiating plate 4 is also preferably fixed with a screw or the like via a heat conduction grease (not shown) because it can be easily replaced while maintaining good heat conduction.

  In the example shown in FIG. 1, heat dissipating means 5 (51, 52) is further provided on the back surface of the heat dissipating plate 4 in order to further improve heat conduction. In the example shown in FIG. 1 as the heat dissipating means 5, an example of the heat dissipating fins 51 and the water flow pipe 52 for water cooling is shown. The heat radiating fins 51 are formed in a structure having a large surface area made of a metal plate having good heat conduction, such as a copper plate, for example, and the heat radiating plates are interposed via the heat conductive grease 6 so that no air layer is interposed between the heat radiating plates 4. 4 and is fixed with screws or the like (not shown), but may be bonded with an adhesive having good thermal conductivity. Although heat dissipation by the water flow pipe 52 requires cooling water, it becomes a large scale, but it shows that these means can be used when heat dissipation is insufficient depending on the input to the light emitting element and the heat dissipation environment, etc. Therefore, it is selected from these means according to the required heat radiation amount. Even in the case where the insulating substrate and the light diffusing plate 3 are attached to a box or the like, these heat dissipating means can be attached, and the heat dissipating means can be formed as it is by forming the box with a thick metal plate having good heat conduction. It can be.

  As shown in FIG. 2, for example, FIG. 2 shows a cross-sectional explanatory diagram of the reflective chip-type light emitting element 1, and a pair of terminal electrodes 12a and 12b are provided from both ends of the insulating substrate 11 to the back surface. The LED chip 13 is bonded on the electrode 12a, and the pair of electrodes of the LED chip 13 are electrically connected to the pair of terminal electrodes 12a and 12b via the wires 14, respectively. In this example, since the substrate of the LED chip 13 is a sapphire substrate 131 and the pair of both electrodes 133 and 134 are led out to the surface side of the LED chip 13, both electrodes are connected by wire bonding. In such a case, the bonding may not be performed on the terminal electrode 12a but may be performed directly on the insulating substrate 11. When one electrode is led out to the back surface of the substrate of the LED chip 13, it is electrically connected by bonding on the one terminal electrode 12a with a conductive adhesive.

  The LED chip 13 is formed for blue light emission. For example, a semiconductor laminated portion 132 in which an n-type layer and a p-type layer are laminated is formed on a sapphire substrate 131 by a nitride semiconductor, and is connected to the n-type layer. Then, the n-side electrode 133 is connected to the p-type layer to form the p-side electrode 134, the n-side electrode 133 is connected to the one terminal electrode 12a and the wire 14, and the p-side electrode 134 is connected to the other side. The terminal electrode 12b and the wire 14 are connected to each other. Even when such a nitride semiconductor is used, conductive SiC can be used for the substrate. In that case, one of the electrodes can be directly connected to the terminal electrode 12a by a conductive adhesive. Here, the nitride semiconductor means a compound in which a group III element Ga and a group V element N or a part or all of a group III element Ga is substituted with other group III elements such as Al and In, and / or Alternatively, it refers to a semiconductor made of a compound (nitride) in which a part of N of the group V element is substituted with another group V element such as P or As.

  The LED chip 13 is surrounded by a reflective case 15 provided around the surface of the insulating substrate 11, and the concave portion of the reflective case 15 is filled with a light-transmitting resin 16 such as an epoxy resin, and the LED chip 13 and The wire bonding part is protected. For example, a YAG (yttrium, aluminum, garnet) phosphor material 17 is mixed in the translucent resin 16 so that, for example, the light emission color of the blue light emitting LED chip 13 is converted to white. However, the light emitting element 1 is not limited to this example. For example, even if white light is used, LED chips that emit three primary colors of red, green, and blue are incorporated in one light emitting element. It is possible to make white light by mixing colors, or to provide light emitting color conversion members that change to red, green, and blue on the surface of the LED chip that emits near ultraviolet light, and to mix the light converted into each color The light can also be made into white light, or a light emitting element having a desired light emitting color can be used instead of white light.

  In the present invention, by controlling the inclination angle of the inner surface of the reflection case 15, the directional characteristics of the light emitting element 1 are formed to be 120 ° ± 20 °, more preferably 120 ° ± 10 °. As shown in FIG. 2 (b), the directivity characteristic is such that the luminance of the light pattern P radiated from the light emitting element 1 is such that the luminance of the portion with the strongest central light intensity becomes half the luminance in the horizontal direction. In the chip type light emitting device 1 having the reflection case 15, as shown in FIG. 2A, the light pattern is represented by the angle of inclination α of the inner surface of the reflection case 15. You can adjust the spread. By forming the inclination angle α of the inner surface of the reflection case 15 to about 60 ° to 120 °, the directivity can be set to about 120 ° ± 20 °.

  That is, the inventor variously changes the relationship between the directivity and the distance d between the light emitting element 1 and the light diffusing plate 3 to change the predetermined distance of light transmitted through the light diffusing plate 3 (in humans indoors). As a result of investigating and examining the luminance at a position of approximately the height of the eyes, the luminance is greatly reduced when the directivity angle is large, for example, 150 ° or more, and when the directivity angle is small, within 90 °, the light-emitting element 1 The distance between the light-emitting element 1 and the light diffusing plate 3 can be made inconspicuous, but when the distance d is increased, the luminance is reduced. It has been found that the light-emitting element 1 having the above-mentioned directivity characteristic θ is preferable.

  For example, a ceramic or epoxy resin substrate can be used as the insulating substrate 2. However, since the number of light emitting elements is large, a ceramic substrate having a high heat conductivity as much as possible is preferable. For example, 0.8-1 A thickness of about 0.6 mm is used. A wiring pattern is formed on the insulating substrate 2 by a copper coating (not shown), and bonding is performed on the copper coating so that the back electrodes of the terminal electrodes 12a and 12b of the light emitting element 1 are directly connected. For example, four connected in series can be connected in parallel and operated with a direct current of about 15V. Further, in this arrangement, for example, as shown in a circuit diagram in FIG. 1C, the light emitting elements 1 arranged in a matrix can be connected in series and parallel and driven by a 100 V AC power supply. For example, the light emitting element 1 has a length L of about 3 mm and a width W of about 2 mm, a horizontal pitch p1 of about 3 ± 0.5 mm, and a vertical pitch p2 of 4 ±. A wiring pattern is formed to be about 0.5 mm, and the size of the insulating substrate 2 is about 1 m in width and about 1.3 m in length. As a result, about 110,000 chip-type light emitting elements 1 are mounted.

  The light diffusing plate 3 is made of a material having good transmittance while diffusing light so that a point light source is not conspicuous. For example, an acrylic plate having a thickness of about 5 mm is used, and is opposed to the insulating substrate 2. It is preferable that the surface on the side to be textured is textured. By applying the embossing process, even if the distance d between the light diffusing plate 3 and the light emitting element 1 is close to about 30 ± 5 mm, the distance between the light emitting elements 1 can be made almost inconspicuous. 3 and the light emitting element 1 can be narrowed, so that there is little loss of light between them, more light is extracted from the light diffusion plate 3, and the luminance can be improved. As the light diffusion plate 3 made of this acrylic plate, one having a transmittance of about 90% was used.

  The heat radiating plate 4 is a metal plate having good thermal conductivity, for example, an aluminum plate or a copper plate having a thickness of about 12 mm. As described above, since the light emitting elements 1 are densely provided in a matrix on the insulating substrate 2 and a current is passed through each light emitting element 1 to emit light, the amount of heat generation is considerably increased. For this reason, it is required from the viewpoint of life and safety management of the light emitting element 1 to quickly dissipate the generated heat, and such a heat radiating plate 4 is provided. In this case, since the light emitting elements 1 are densely provided on the insulating substrate 2, there is no space for screwing, and the insulating substrate 2 is bonded with an adhesive having good heat conduction, such as a modified acrylic adhesive. It is glued to the back side. However, when there is a space for screwing and the screwing is performed in consideration of the convenience when the insulating substrate 2 is replaced, heat conductive grease may be applied and bonded between the two. In any case, it is preferable to join the insulating substrate 2 and the heat sink so that no air layer is interposed therebetween. As described above, the heat radiating plate 4 is further joined to the mounting plate 8 or the like to radiate heat by heat conduction, or the second heat radiating means 5 is provided on the back side of the heat radiating plate 4.

As described above, according to the present invention, light is uniformed by a light diffusing plate having certain irregularities such as embossing while adjusting directivity using a reflective chip-type light emitting element. Therefore, the distance d between the light emitting element and the light diffusing plate is very small as about 30 mm, and even if a light diffusing plate having a high transmittance of about 90% is used, no shadow between the light emitting elements appears. It can be a very uniform and bright lighting device. When a current of 20 mA per element was passed by the DC drive described above, a brightness of 7000 lux was obtained in a room with a size of 20 m ² . This is about the same brightness as about 80 32 W fluorescent lamps.

It is explanatory drawing of one Embodiment of the illuminating device by this invention. It is a cross-sectional explanatory drawing and directivity explanatory drawing of the light emitting element used in the example of FIG. It is a figure which shows the example of the electric light type illuminating device using the conventional light emitting element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting element 2 Insulating substrate 3 Light diffusing plate 4 Heat radiating plate 5 2nd heat radiating means 6 Thermal conduction grease 11 Insulating substrate 12 Terminal electrode 13 LED chip 14 Wire 15 Reflecting wall 16 Translucent resin 17 Luminous color conversion member

Claims (4)

  An insulating substrate having electrode wiring formed on one surface, and a matrix mounted so as to be connected to the electrode wiring on one surface of the insulating substrate, each of which is connected in series and / or in parallel A reflective chip-type light-emitting element, a light diffusion plate provided on the light-emitting surface side of the chip-type light-emitting element at a predetermined interval from the chip-type light-emitting element, and an air layer on the other surface side of the insulating substrate The illuminating device which comprises the heat sink provided so that it may not exist.   2. The planar illumination device according to claim 1, wherein a surface of the light diffusing plate facing the light emitting element chip is subjected to a textured process.   The planar lighting device according to claim 1 or 2, wherein a heat radiating means is provided on a surface of the heat radiating plate opposite to a surface on which the insulating substrate is provided.   4. The planar illumination device according to claim 1, wherein a directivity characteristic of the reflective chip-type light emitting element is 120 ° ± 20 ° in an angle where the output is halved. 5.

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