JP2004335524A - Light emitting diode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting diode that can be adjusted in the angle of luminous intensity distribution without increasing its thickness. <P>SOLUTION: This light emitting diode is constituted by covering the upper part of a light emitting element 14 with a first transparent member 18 and forming a first air space 19 between the transparent member 18 and a base substrate 11. Then the upper part of the first transparent member 18 is covered with a second transparent member 21, and the projecting section 20 of the first transparent member 18 is fitted in the recessed section 22 of the second transparent member 21. At the same time, a second air space 23 is formed of the recess 24 of the second transparent member 21 between the first and second transparent members 18 and 21. In addition, annular convex lenses 25 are formed on one side of the second transparent member 21 opposite to the first transparent member 18 for adjusting the angle of luminous intensity distribution. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a light emitting diode used for a lighting device and the like.
[0002]
[Prior art]
2. Description of the Related Art In general, chip-type light emitting diodes are widely used as backlight light sources for liquid crystal display units of mobile phones and small electronic devices and light sources of various lighting devices. FIG. 5 is a side view of a conventional light emitting diode. The base substrate 11 and the reflection member 28 are integrally formed of a white resin, metal lead frames 12a and 12b are provided on both left and right sides of the base substrate 11, and a first electrode portion 13a formed on one of the lead frames 12a. The light emitting element 14 is mounted on the second lead frame 12b, and is connected to the second electrode portion 13b formed on the other lead frame 12b by the metal wire 15. Then, the metal wire and the upper part of the light emitting element 14 are covered with a transparent resin package.
[0003]
As described above, the light emitting element 14 which is a semiconductor chip is disposed on the first electrode portion 13a of the metal lead frame 12a disposed on the base substrate 11, and the light emitting element 14 is filled with the transparent resin 16 to form a resin. The light emitting element 14 is sealed in a package made of a light emitting diode. When the light distribution angle is reduced, a convex lens 17 is provided on the front surface of the transparent resin 15 as shown in FIG. 6, and the light from the light emitting element 14 is refracted by the convex lens 17 on the front surface to reduce the light distribution angle. Adjustments were being made.
[0004]
[Problems to be solved by the invention]
However, when the light is condensed by the convex lens 17 or the like, the distance between the light emitting element 14 and the convex lens 17 needs to be equal to or greater than the radius of the R surface of the convex lens 17.
[0005]
An object of the present invention is to provide a light emitting diode that can adjust a light distribution angle without increasing the thickness of the light emitting diode.
[0006]
[Means for Solving the Problems]
A light emitting diode according to the first aspect of the present invention includes a light emitting device disposed on a base substrate on which an electrode portion is formed; and forming a first air layer between the light emitting device and an upper portion of the light emitting device and the base substrate. A first transparent member having a convex portion on the opposite side facing the light emitting element; a concave portion fitted to the convex portion of the first transparent member on a side facing the first transparent member; and the first transparent member; A second transparent member having a surface in which a concave portion forming a second air layer is interposed therebetween; and an annular convex lens formed on a side of the second transparent member opposite to the first transparent member. And;
[0007]
In the present invention and the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.
[0008]
The base substrate is formed integrally with the reflection member using white resin, and the electrode portion is formed integrally with the lead frame. Then, the white resin and the lead frame are integrally molded. The light emitting element is a semiconductor chip, which emits light when power is supplied from the electrode portion.
[0009]
The first transparent member is formed of a transparent resin, covers an upper part of the light emitting element, and forms a first air layer between the first transparent member and the base substrate. Further, a convex portion is provided on the opposite side facing the light emitting element. The second transparent member is formed of a transparent resin, has a concave portion on the side facing the first transparent member, the concave portion being fitted to the convex portion of the first transparent member, and forms a second air space between the second transparent member and the first transparent member. And a concave portion. Further, an annular convex lens is formed on the opposite side of the second transparent member facing the first transparent member. The annular convex lens collects light rays and emits light rays to the outside.
[0010]
Therefore, the boundary surface where the first transparent member and the second transparent member are in contact with each other includes a fitting portion between the convex portion of the first transparent member and the concave portion of the second transparent member, and a portion where the second air tank is formed. Is obtained. Light rays from the light emitting element are incident on a boundary surface where the first transparent member and the second transparent member are in contact with each other, and light rays hitting the bottom of the second air layer at the boundary surface are totally reflected and incident on the first air layer. Then, the light is further totally reflected by the first air layer and is incident on a boundary surface where the first transparent member and the second transparent member come into contact with each other. On the other hand, a light beam hitting a fitting portion between the convex portion of the first transparent member and the concave portion of the second transparent member at the boundary surface where the first transparent member and the second transparent member come into contact passes through the fitting portion. And enters the second transparent member, is totally reflected by the inclined surface of the second air layer, is condensed by the annular convex lens, and is emitted to the outside.
[0011]
According to the present invention, since the total reflection is used, the reflection loss is small, and in order to adjust the light distribution angle, the radius of curvature of the front annular convex lens is changed or the concave portion for forming the second air layer is formed. It is possible to provide a light-emitting diode that can easily adjust the light distribution angle without attenuating the light rays from the light-emitting element and without increasing the thickness of the light-emitting diode.
[0012]
According to a second aspect of the present invention, in the light emitting diode according to the first aspect, a low refractive index material layer having a refractive index of 1 or more and less than 1.45 is provided in place of the first air layer and the second air layer. The first transparent member and the second transparent member are integrally formed of a high refractive index material layer having a refractive index of 1.45 or more and less than 2.
[0013]
According to the present invention, a low refractive index material layer having a refractive index of 1 or more and less than 1.45 is provided in place of the first air layer and the second air layer, and the first transparent member and the second transparent member are provided with a refractive index of 1.45. More than two and less than two high refractive index material layers are integrally formed.
[0014]
According to the present invention, the high-refractive-index material layer 27 is formed integrally and overlaps because the low-refractive-index material layer having a gradient of 1 or more and less than 1.45 is included in the high-refractive-index material layer. Since there is no portion, in addition to the effect of the first aspect, the light emission efficiency is further improved.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described. FIG. 1 is an explanatory view of a light emitting diode according to a first embodiment of the present invention. FIG. 1 (a) is a plan view and FIG. 1 (b) is a side view. The base substrate 11 and the reflection member 28 are integrally formed of a white resin, and metal lead frames 12 a and 12 b are attached to both left and right sides of the base substrate 11. The light emitting element 14 is mounted and connected to the first electrode portion 13a formed on one lead frame 12a, and is connected to the second electrode portion 13b formed on the other lead frame 12b by the metal wire 15. . Thus, power is supplied to the light emitting element 14.
[0016]
The upper part of the light emitting element 14 is covered with the first transparent member 18. At this time, a first air layer 19 is formed between the first transparent member 18 and the base substrate 11 (lead frame 12). Further, a projection 20 is formed on the opposite side of the first transparent member 18 facing the light emitting element 14. Further, the upper part of the first transparent member 18 is covered with a second transparent member 21. On the side of the second transparent member 21 facing the first transparent member 18, there is provided a concave portion 22 that fits into the convex portion 20 of the first transparent member 18, and the second transparent member 21 and the first transparent member 18 are provided. A concave portion 24 for forming the second air layer 23 is provided between the first and second air layers. On the other hand, an annular convex lens 25 is provided on the opposite side of the second transparent member 21 facing the first transparent member 18. The annular convex lens 25 is provided to increase the light collecting property.
[0017]
As described above, the first air layer 19 is provided around the light emitting element 14 which is a point light source, and the annular projections (projections 20) are arranged at a certain interval on the opposite side of the first air layer 19. The transparent member 18 is provided, and the second transparent member 21 having the concave portion 22 having the same shape as the projection (convex portion 20) of the first transparent member 18 and the concave portion 24 forming the second air layer 23 is overlapped. Then, the convex portion 20 of the first transparent member 18 and the concave portion 22 of the second transparent member 21 are fitted together, and the second air layer 23 is formed.
[0018]
Therefore, the boundary surface where the first transparent member 18 and the second transparent member 21 come into contact with each other is formed by the fitting portion between the convex portion 20 of the first transparent member 18 and the concave portion 22 of the second transparent member 21 and the second air space. It becomes a composite surface with the portion where 23 is formed. An annular convex lens 25 for adjusting the light distribution angle is provided on the light exit side of the second transparent member 21.
[0019]
FIG. 2 is a ray tracing diagram showing how rays from the light emitting element 14 are emitted from the annular convex lens 25 in the first embodiment. Light rays make two major movements. First, the light beam from the light emitting element 14 strikes the bottom of the second air layer 23. In this case, the light ray is totally reflected by the second air layer 23, It is a light ray directed to the side surface. Then, the first air layer 19 on the light emitting element 14 side is also totally reflected, and the same is repeated when the reflected light hits the second air layer 23 again.
[0020]
Next, the second is a case where a light beam hits a portion where the convex portion 20 and the concave portion 22 overlap. In this case, the light beam from that portion enters the second transparent member 21 on the front surface and the second air The light is totally reflected upon hitting the inclined portion forming the layer 23, and the totally reflected light is emitted to the outside through the annular convex lens 25. In addition, the annular convex lens 25 is used to increase the light collecting property.
[0021]
According to the first embodiment, the light rays from the light emitting element 14 are ultimately condensed by the annular convex lens 25 using the total reflection in the first air layer 19 and the second air layer 23. Since the light beam is emitted to the outside, the reflection loss is small as a whole. Further, the light distribution angle can be adjusted by changing the radius of curvature of the annular convex lens 25 on the front surface or by changing the inclination angle of the concave portion 24 forming the second air layer 23. The angle can be adjusted.
Next, a second embodiment of the present invention will be described. FIG. 3 is an explanatory view of a light emitting diode according to a second embodiment of the present invention. FIG. 3 (a) is a plan view and FIG. 3 (b) is a side view. This second embodiment is different from the first embodiment shown in FIG. 1 in that a low refractive index material having a refractive index of 1 or more and less than 1.45 is used instead of the first air layer 19 and the second air layer 23. The layers 26a and 26b are provided, and the first transparent member 18 and the second transparent member 21 are integrally formed of a high refractive index material layer 27 having a refractive index of 1.45 or more and less than 2. The same elements as those shown in FIG. 1 and the first embodiment are denoted by the same reference numerals, and redundant description is omitted.
[0022]
In FIG. 3, a low-refractive-index material layer 26a is formed instead of the first air layer 19 around the light emitting element 14 arranged on the first electrode portion 13a of the lead frame 12a of the base substrate 11, and on the upper portion thereof. The high refractive index material layer 27 is formed. The high-refractive-index material layer 27 embeds a low-refractive-index material in a high-refractive-index material, forms a low-refractive-index material layer 26b inside the high-refractive-index material layer 27, and forms the first transparent member 18 and the second transparent member. The member 21 is formed integrally. The low refractive index material layers 26a and 26b use a low refractive index material having a refractive index of 1 or more and less than 1.45, and the high refractive index material layer 27 has a high refractive index material having a refractive index of 1.45 or more and less than 2. Use
[0023]
FIG. 4 is a ray tracing diagram showing how rays from the light emitting element 14 are emitted from the annular convex lens 25 in the second embodiment. As in the case of the first embodiment, the light beam roughly divides into two movements. First, the light beam from the light emitting element 14 hits the bottom of the low-refractive-index material layer 26b. In this case, the light beam is totally reflected by the low-refractive-index material layer 26b. The light is directed toward the surface on the element 14 side. Then, the low-refractive-index material layer 26a on the side of the light-emitting element 14 is also totally reflected. When the reflected light hits the low-refractive-index material layer 26b again, the same is repeated. Next, in the second case, a light beam hits the inclined surface of the low refractive index material layer 26b. In this case, the light impinges on the inclined surface forming the low refractive index material layer 26b, and the light is totally reflected. The light exits through the annular convex lens 25 to the outside.
[0024]
In FIG. 4, since the high-refractive-index material layer 27 is formed integrally and has no overlapping portion, there is no loss in the overlapping portion, and the efficiency is further improved. Also in this case, the light distribution angle can be adjusted by changing the radius of curvature of the front annular convex lens 25 or by changing the inclination angle of the embedded low refractive index material layer 26b.
[0025]
According to the second embodiment, the light beam from the light emitting element 14 utilizes the total reflection in the low refractive index material layers 26a and 26b and is finally condensed by the annular convex lens 25 and emitted to the outside. The reflection loss is small as a whole. Further, since the high refractive index material layer 27 is formed integrally and has no overlapping portion, the efficiency is further improved. The light distribution angle can be easily adjusted by changing the radius of curvature of the front annular convex lens 25 or by changing the inclination angle of the concave portion 24 forming the low refractive index material layer 26b. The light angle can be adjusted.
[0026]
【The invention's effect】
As described above, according to the first aspect of the present invention, since the total reflection is used, the reflection loss is small, and in order to adjust the light distribution angle, the radius of curvature of the front annular convex lens is changed. Or by changing the inclination angle of the concave portion forming the second air layer, the light distribution angle can be easily adjusted without attenuating the light rays from the light emitting element and without increasing the thickness of the light emitting diode. An adjustable light emitting diode can be provided.
[0027]
According to the second aspect of the present invention, the high refractive index material layer 27 includes the low refractive index material layer having a gradient of 1 or more and less than 1.45 inside the high refractive index material layer. Since there is no overlapping part, the light emitting efficiency is further improved in addition to the effect of the first aspect of the present invention.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a light emitting diode according to a first embodiment of the present invention.
FIG. 2 is a ray tracing diagram showing how a ray from a light emitting element is emitted from an annular convex lens according to the first embodiment of the present invention.
FIG. 3 is an explanatory diagram of a light emitting diode according to a second embodiment of the present invention.
FIG. 4 is a ray tracing diagram showing how rays from a light emitting element are emitted from an annular convex lens according to a second embodiment of the present invention.
FIG. 5 is a side view of a conventional light emitting diode.
FIG. 6 is a side view of a light emitting diode having a conventional convex lens.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Base board, 12a ... Metal lead frame, 13a ... 1st electrode part, 13b ... 2nd electrode part, 14 ... Light emitting element, 15 ... Metal wire, 16 ... Transparent resin, 17 ... Convex lens, 18 ... 1st Transparent member, 19: first air layer, 20: convex portion, 21: second transparent member, 22: concave portion, 23: second air layer, 24: concave portion, 25: annular convex lens, 26: low refractive index material layer , 27: High refractive index material layer, 28: Reflecting member

Claims (2)

A light emitting device installed on a base substrate on which an electrode unit is formed;
A first transparent member which covers an upper portion of the light emitting element, forms a first air layer between the light emitting element and the base substrate, and has a convex portion on a side opposite to the light emitting element;
On the side facing the first transparent member, there was provided a combined surface of a concave portion fitted to the convex portion of the first transparent member and a concave portion forming a second air layer between the first transparent member. A second transparent member;
An annular convex lens formed on the opposite side of the second transparent member facing the first transparent member;
A light emitting diode comprising: A low refractive index material layer having a refractive index of 1 or more and less than 1.45 is provided in place of the first air layer and the second air layer, and the first transparent member and the second transparent member are provided with a refractive index of 1.45. 2. The light-emitting diode according to claim 1, wherein the light-emitting diode is formed integrally with at least two high refractive index material layers.

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