JP4129570B2 - Light emitting diode lighting device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light-emitting diode illuminating device having a high light intensity, which is arranged so as to collect emitted light, such as a plurality of light-emitting diodes, for example, a face-bonding light-emitting diode or a light-emitting diode with lens.
[0002]
[Prior art]
Nowadays, LEDs (Light Emitting Diodes) having various emission wavelengths from infrared light to ultraviolet light are manufactured and widely used for optical communication, various displays, various illuminations, and the like.
As a feature of the LED, its emission spectrum has a narrower spectrum width than other conventional light sources, that is, high monochromaticity, and that a desired spectrum can be selected by combining LEDs having various emission wavelengths, and The light emitting efficiency is high and heat generation is small, and the demand for LED lighting devices that take advantage of these features is increasing.
For example, in plant cultivation, it is known that the growth rate of plants is significantly increased by irradiating a large amount of light having a specific wavelength, and plant cultivation farmers need a lighting device with high intensity at a specific wavelength. It is said.
Also, in the field of the biochemical industry, it is used for applications such as irradiating a large amount of light with specific wavelengths or different emission wavelengths at the same time to promote specific biochemical reactions and increase the production efficiency of chemicals, etc. There is a need for a lighting device that can be used.
Further, in the lighting field such as display, decoration, and stage, there is a need for a lighting device that can change color and tone arbitrarily, has high luminous efficiency, little heat generation, and high intensity that can be confirmed from a distance.
[0003]
Thus, LED lighting devices that can illuminate light of a specific wavelength with high intensity are required in various industrial fields.
However, the LED has a limitation due to the operation principle of passing a current through the semiconductor junction, and it is difficult to obtain an LED chip with sufficiently high light intensity that can be compared with a halogen lamp. A semiconductor light source with high light intensity includes LD (Laser Diode), but short wavelength LDs such as blue have disadvantages that it is difficult to produce an optical resonator and are difficult to obtain or are extremely expensive.
Thus, although the LED lighting apparatus with high light intensity is required, the LED lighting apparatus which has still sufficient light intensity is not implement | achieved.
[0004]
[Problems to be solved by the invention]
In view of the above problems, an object of the present invention is to provide a light-emitting diode illuminating device with high light intensity.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a light-emitting diode illuminating device of the present invention includes a bulk-type lens having a gap and a light source, and the bulk-type lens has a cylindrical outer surface and a first convex spherical surface. The lens surface has a cylindrical inner surface and a concave spherical second lens surface, and the cylindrical outer surface is configured to function as a reflecting surface, and the light source includes a plurality of light emitting diodes. Are arranged on the concave surface, and the light source is included in the gap of the bulk type lens.
According to this configuration, since the light emitting diodes densely arranged on the concave surface are included as the light source in the gap of the bulk type lens, an extremely efficient light emitting diode illuminating device can be realized.
[0007]
Further, in the present invention, it is preferable that a cooling means for promoting heat dissipation is provided on a fixing member of an electrode of a light emitting diode, particularly a face bonding type light emitting diode. This cooling means may be a Peltier element or a heat pipe.
Although the cooling means with these configurations does not have a high cooling capacity, it uses a face-bonding type light emitting diode that generates very little heat and dissipates heat. It does not require the bulky cooling device that is indispensable. Therefore, it is possible to realize a compact lighting device with extremely high light intensity.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that substantially the same members will be described using the same reference numerals.
First, a first embodiment of the present invention will be described.
FIG. 1 is a diagram showing a first embodiment of a light-emitting diode illuminating device of the present invention, FIG. 1 (A) is an external perspective view, and FIG. 1 (B) is a cross-sectional view taken along line AA of FIG. . In FIG. 1A, the electrode pattern is not shown for easy viewing.
1A and 1B, a light-emitting diode illuminating device 10 includes a support portion 11 having a concave end, a cooling portion 12 that is in close contact with the concave surface of the support portion 11, and a concave surface of the cooling portion 12. The substrate 13 has a concave surface 14 in close contact, an electrode pattern 15 provided on the concave surface 14 of the substrate 13, and a plurality of light emitting diodes 16 bonded to the electrode pattern 15. The concave surface 14 has a focal point P. For example, spherical surfaces, paraboloids, ellipsoids, hyperboloids, and the like.
[0010]
Light emitting diodes inherently generate little heat, but if a large number of LEDs are densely arranged as in the present embodiment, countermeasures for heat generation must be taken, and therefore the cooling unit 12 is arranged in close contact with the back side of the substrate 13. is doing. The cooling unit 12 can be sufficiently cooled by using an electronic cooler such as a Peltier element or a heat pipe. In addition, a fin for promoting heat dissipation may be provided in the cooling unit 12 to perform natural or forced air cooling. The heat of the cooling unit 12 is also radiated from the support unit 11.
The substrate 13 is made of a material having high thermal conductivity, for example, a metal such as Al, Fe, or Cu, a polymer material such as acrylic resin, polycarbonate, or delrin, glass, and the like. It is mirror finished by grinding and polishing after pressing. In addition, when the material of the board | substrate 13 has electroconductivity, an insulating film is formed in the concave surface finished mirror surface, and the electrode pattern 15 is formed. This insulating film is formed, for example, by attaching a plastic film sheet of 1 mm or less, thermal oxidation, plating of an insulating material, vapor deposition or sputtering.
Further, the electrode pattern 15 of the substrate 13 is formed by, for example, a transparent electrode made of an ITO film or the like, or a conductive pattern made of a metal such as Al, Au, or Ag.
[0011]
Here, the face bonding type light emitting diode will be described.
Light emitting diode chips include a wire bonding type and a face bonding type chip. The wire bonding type chip is one in which one or both of electrodes for applying a current to a pn junction and a power supply electrode of a substrate are connected by a bonding wire. For this reason, in the wire bonding type chip, there is a problem that the bonding wire blocks light emission and a uniform light intensity distribution cannot be obtained, and heat dissipation of the chip is performed through the bonding wire, so heat dissipation is poor. There is a problem that the chip temperature tends to rise.
[0012]
On the other hand, the face bonding type chip has both electrodes for applying a current to the pn junction on the chip back surface, and this electrode has a wide area that substantially occupies the entire chip back surface. Further, the face bonding type chip can be electrically connected and fixed simultaneously by thermocompression bonding the electrode on the back surface of the chip to the electrode pattern on the substrate. Therefore, if a face bonding type chip is used, the need for wire bonding is eliminated, the process is simplified, a uniform light intensity distribution is obtained because there is no bonding wire, and the contact area with the substrate is large. The heat dissipation is good and the chip temperature is hard to rise. The present invention can be applied to either the wire bonding type chip or the face bonding type chip described above, but the latter chip is more advantageous. Hereinafter, a face bonding type light emitting diode will be described as an example.
[0013]
FIG. 2 is a diagram showing a configuration of a face-bonding type light emitting diode used in the present embodiment.
In the figure, a face bonding type light emitting diode 16 is formed by laminating a transparent substrate 17 such as sapphire, a semiconductor layer 18 having p or n type conductivity, and a semiconductor layer 19 having n or p type conductivity. The semiconductor layer 18 and the semiconductor layer 19 are electrically separated via the recessed fitting portion 20. Electrodes 21 and 21 are respectively provided on the lower surfaces of the semiconductor layer 18 and the semiconductor layer 19 that are electrically separated via the recessed fitting portion 20, and the electrodes 21 and 21 are in the same plane.
In the face bonding type light emitting diode 16, the electrodes 21 and 21 of the face bonding type light emitting diode 16 are bonded and fixed to the electrodes 15 and 15 of the substrate 13, and electrical connection is also completed. The area of the electrodes 21 and 21 and the electrodes 15 and 15 is much larger than the diameter of the bonding wire, and therefore has good heat dissipation.
Since the light emitting diode illuminating device according to the first embodiment of the present invention uses a face bonding type light emitting diode, the light intensity distribution is uniform and the temperature rise is small. Moreover, since the size is extremely small as compared with the LED with a lens using a bullet-type lens, it can be arranged with high density.
2 is not limited to the face bonding type light emitting diode 16 having the configuration shown in FIG. 2, and any light emitting diode chip having a face bonding type electrode structure may be used. For example, a surface mounting type LED ( SMD) can be used in the same manner.
[0014]
According to the light-emitting diode illuminating device 10 of the first embodiment configured as described above, the light emission of all the face-bonding light-emitting diodes 16 is collected at the focal point P of the concave surface 14, and the light intensity at the focal point P is The intensity increases in proportion to the number of bonding type light emitting diodes 16. Therefore, if an object is placed at the point P, high-intensity LED light can be irradiated. Further, if the object is placed at a position away from the focal point P, the object can be irradiated with divergent light with high light intensity using the point P as a light source. Moreover, if the structure of the recessed part 14 is made into convex shape, an irradiation area can be expanded.
[0015]
Next, an application example of a face bonding type light emitting diode that obtains high intensity convergent light using the first embodiment will be described.
FIG. 3 is a diagram showing an application example of convergent light formation using the light-emitting diode illuminating device 10 of the first embodiment as a light source. FIG. 3A is an example using a conventional optical lens, and FIG. B) shows an example using a bulk lens, and FIG. 3C shows an example using a lens-shaped resin.
In FIG. 3A, the light emission L of all the light-emitting diodes mounted on the light-emitting diode illuminating device 10 is condensed at the focal point P, and the convergent light beam is emitted by the lens 25 arranged with the focal point P as the light source and separated by the focal length. It is formed.
According to this configuration, convergent light having an intensity proportional to the number of light emitting diodes mounted on the light emitting diode illumination device 10 can be obtained.
In FIG. 3B, the focal point P of the light-emitting diode illuminating device 10 is disposed so as to coincide with the light source position of the bulk lens 26, and the light emission L of all the light-emitting diodes mounted on the light-emitting diode illuminating device 10 is achieved. Is focused at the focal point P and converged by the bulk lens 26 with the point P as a light source.
[0016]
Here, the bulk type lens will be described. A bulk lens is, for example, a bullet-shaped lens having a gap for containing a light emitter, and can converge almost all of the light emission of a semiconductor light emitting device such as an LED enclosed in the gap. The details of this have been developed by Japanese Patent Application No. 2001-20825.
FIG. 7 is a cross-sectional view showing the configuration of the bulk lens.
In the figure, the bulk lens 70 is composed of a transparent optical medium 76 composed of a first lens surface 71, a second lens surface 72, an inner surface 73, an outer surface 74, and a bottom surface 75. It is a bulk body. The first lens surface 71 and the second lens surface 72 are curved surfaces having a lens action corresponding to the purpose of use such as collimation, convergence or divergence of light. In the example shown in the figure, when viewed from the optical medium 76, The first lens surface 71 is a convex spherical surface, and the second lens surface 72 is a concave spherical surface. The inner side surface 73 and the outer side surface 74 are cylindrical surfaces in this example. The figure shows a state in which an LED chip 77 is supported on a support base 78 and mounted on a bulk lens 70 to emit light, and its luminous flux 79 is converged and emitted.
[0017]
Since this bulk lens 70 has a structure in which a light source is included in a convex lens, a loss caused in the case of the prior art in which a spherical convex lens is brought close to the light source to form parallel rays, that is, the curvature radius and focal length of the convex lens. Therefore, there is no loss due to the inability to converge a light beam having an aperture angle determined from the above relationship.
In addition, when a spherical convex lens is brought close to a light source and converged, Fresnel reflected light on the lens surface is scattered into space and cannot be used as convergent light. However, in the case of a bulk type lens, a bulk type lens is used. Since the light source is included in the convex lens, the Fresnel reflected light generated on the first lens surface 71 and the second lens surface 72 is not dissipated from the bulk lens, and a part thereof is The light is reflected by the side surface 73, the outer surface 74, and the bottom surface 75, and returns to the first lens surface 71 again to become convergent light. The other part of the Fresnel reflected light returns to the LED chip 77, and the pn junction of the LED chip 77 Absorbs and re-emits light.
Therefore, according to the configuration of FIG. 3B, almost all of the light emission of the light emitting diodes mounted on the light emitting diode illumination device 10 can be converged, and convergent light with high light intensity can be obtained extremely efficiently.
[0018]
Next, the configuration of FIG. 3C will be described.
In the figure, the light emitting diode illumination device 10 is provided with a lens-like transparent or translucent resin 27 so as to cover the light emitting surface of the light emitting diode illumination device 10.
The transparent or translucent resin 27 is a transparent or translucent plastic resin, a silicone polymer having high transparency and exhibiting appropriate elasticity, a fluorine-based polymer, a thermoplastic elastomer, an ultraviolet curable resin, or the like.
According to this configuration, convergent light with high light intensity proportional to the number of light emitting diodes mounted on the light emitting diode illumination device 10 can be obtained.
[0019]
Next, a second embodiment of the light-emitting diode illuminating device of the present invention will be described.
FIG. 4 is a perspective view showing a second embodiment of the light-emitting diode illuminating device of the present invention, and FIG. 5 is a cross-sectional view of the light-emitting diode illuminating device shown in FIG.
In FIG. 4, the light-emitting diode illuminating device 40 uses an annular substrate 41 instead of the concave substrate 13 in the first embodiment, and the face bonding type light-emitting diode 16 is placed on the inner surface 41 a of the annular substrate 41. Arranged along the circumferential direction of the ring, a light reflector 43 having a ring axis 48 as a central axis of symmetry is provided at the center of the ring. Further, the annular substrate 41 may have the radiation fins 41b as shown in FIG. 5, or may have cooling means such as Peltier elements and heat pipes as shown in FIG. good.
[0020]
The reflector 43 is a rotating curved cone whose cross section including the ring axis 48 of the reflector 43 has a quadratic curve convex toward the ring axis 48, and the convex quadratic curve is a face bonding type light emitting diode 16. It is a parabola that focuses on the mounting position. The rotating curved surface cone 43 has an apex in the light emission direction, in the right direction in the figure.
The reflector 43 is formed by processing a part of the surface of the housing 44, and the annular substrate 41 is screwed onto the housing 44 so that the ring axis 48 of the substrate 41 coincides with the central axis of symmetry of the reflector 43. This is an example of being fixed. The reflector 43 may be manufactured as an independent member and attached to the housing 44.
[0021]
The inner surface 41a of the annular substrate 41 is made of an insulator or a conductor whose surface is covered with an insulator, and the face bonding type light emitting diode 16 is bonded to an electrode pattern 42 for power supply provided on the inner surface 41a. Are fixed and electrically connected.
The electrode pattern 42 is connected to a lead wire 46 and is connected to an external power connection terminal 47 provided on the back surface of the mounting fixing portion 45.
The attachment fixing portion 45 has a screw portion 45a and can be screwed and fixed to the socket. Alternatively, the connection to the external power source may be a method of being inserted into a socket and fixed.
[0022]
According to the illumination device 40 of the second embodiment configured as described above, the light emission L emitted from each light emitting diode 16 with a finite divergence angle includes the ring axis 48 as shown in FIG. The light is incident at different positions on the ridge line 43a of the reflector 43 according to the in-plane divergence angle. Since the ridge line 43a has a parabolic shape focusing on the mounting position of the light emitting diode 16, each light emission incident on a different position of the ridge line 43a is reflected in the direction of the ring axis 48 to obtain a parallel light beam with high light intensity. It is done.
[0023]
Next, another example of the second embodiment of the present invention will be described.
FIG. 6 is a perspective view showing another example of the second embodiment.
In this example, the shape of the reflector is different from that of the second embodiment.
In the drawing, the reflector 53 has a quadratic curve in which the ridge line 43a of the cross section including the ring axis 48 of the reflector 53 is convex toward the ring axis 48, and this quadratic curve indicates the mounting position of the light emitting diode 16. It has a parabolic shape as a focal point, and is a curved pyramid composed of a plurality of curved planes 53b having two sides of this quadratic curve.
It is preferable to provide the curved planes 53b as many as the number of face bonding type light emitting diodes 16 at a position facing the light emitting surface of each face bonding type light emitting diode 16.
[0024]
According to the illumination device 50 of the second embodiment having this configuration, the light emitted from each light emitting diode 16 with a finite divergence angle is an in-plane divergence angle including the ring axis 48, and the ring. Depending on the angle of divergence in the plane perpendicular to the axis 48, the light is incident at different positions on the curved plane 53b of the reflector 53, and the emitted light incident at different positions on the curved plane 53b is curved. Since the plane 53b is a curved plane having two sides of a quadratic curve having a parabolic shape focusing on the mounting position of the light emitting diode 16 toward the ring axis 48, each is reflected in the direction of the ring axis 48 and has high light intensity. Parallel rays are obtained.
[0025]
In the first and second embodiments, if a plurality of light emitting diodes having different light emission wavelengths are mixed and used, and light emission of each light emitting diode is controlled independently, light emission of a desired hue and color tone can be obtained. Obviously, it is also obvious that light emission having a desired hue and tone can be obtained by providing fine irregularities on the surfaces of the reflectors 43 and 53.
In the first and second embodiments, a face bonding type light emitting diode is used as the light emitting diode. However, a so-called lens light emitting diode in which the periphery of the LED chip is molded into a convex lens shape with a transparent resin is used. It is obvious that a light-emitting diode illuminating device can be used, and the illuminating device thus configured can be included in a bulk type lens and mounted.
Since the illumination device of the present invention has a high light intensity, it is extremely useful when used for a traffic light or a display device that requires confirmation from a distance.
[0026]
【The invention's effect】
As understood from the above description, according to the light-emitting diode illuminating device of the present invention, a light-emitting diode illuminating device with high light intensity can be obtained.
It is extremely useful when used in the fields of plant growth and biochemistry, and in the lighting field such as display, decoration, and stage, where it is necessary to irradiate a large amount of LED light of a specific wavelength.
Further, it is extremely useful when used for a traffic light or display device that needs to be confirmed from a distance.
[Brief description of the drawings]
1A and 1B show a first embodiment of a light-emitting diode illuminating device of the present invention, in which FIG. 1A is an external perspective view, and FIG. 1B is a schematic cross-sectional view taken along line AA in FIG.
FIG. 2 is a cross-sectional view showing a configuration of a face-bonding type light emitting diode used in the present invention.
FIGS. 3A and 3B show an application example of convergent light formation using the light-emitting diode illuminating apparatus of the first embodiment as a light source, FIG. 3A shows an example using a conventional optical lens, and FIG. (C) is a schematic diagram of an example using a lenticular resin.
FIG. 4 is a perspective view showing a second embodiment of the light-emitting diode illuminating device of the present invention.
5 is a cross-sectional view of the light-emitting diode illuminating device shown in FIG.
FIG. 6 is a perspective view showing another example of the second embodiment.
FIG. 7 is a cross-sectional view showing a configuration of a bulk type lens.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Light emitting diode illuminating device 11 by 1st Embodiment Support part 12 Cooling part 13 Substrate 14 Concave surface 15 Electrode pattern 16 Face bonding type light emitting diode chip 17 Transparent substrate 18 p or n type semiconductor layer 19 n or p type semiconductor layer 20 Concave portion 21 Light emitting diode chip electrode 25 Convex lens 26 Bulk lens 27 Lens-like transparent resin 40 Light emitting diode illuminating device 41 according to the second embodiment Annular substrate 41a Annular substrate inner surface 41b Cooling fin 42 Electrode patterns 43, 53 Reflector 43a Reflector ridge 44 Case 45 Mounting fixing part 45a Screw part 47 External power supply connection terminal 48 Annular axis 50 Another light emitting diode illumination device 53b according to the second embodiment P Curved plane P Focus L Light flux

Claims (3)

A bulk type lens having a gap and a light source,
  The bulk type lens has a cylindrical outer surface, a first convex spherical lens surface, and a cylindrical inner surface and a concave second lens surface. The outer surface of is configured to function as a reflective surface,
  The light source comprises a plurality of light emitting diodes arranged on a concave surface,
  The light-emitting diode illuminating device, wherein the light source is included in the gap of the bulk lens. The light-emitting diode illuminating apparatus according to claim 1, wherein the light-emitting diode electrode fixing member is provided with cooling means for promoting heat dissipation. The light emitting diode illuminating device according to claim 1, wherein the light emitting diode is a face bonding type light emitting diode.

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