JPH0145162B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a lighting device suitable for use in vehicle lamps, etc., and particularly in a lighting device that uses a large number of light emitting diodes as a light source, a light source located diagonally in front of a semiconductor chip. The present invention relates to a lighting device that effectively utilizes light emitted from the outside to improve lighting effects.

[Conventional technology]

In recent years, with the development of semiconductor technology, high-brightness light-emitting diodes have been developed, and as they have become available at low prices, consideration has been given to using them in place of light bulbs as light sources for vehicle lighting, especially brake lights and taillights. As one example, the one shown in FIG. 5 is known. This lamp body 4 is formed by a back cover 1 whose front side is open and a front lens 2 which has a large number of diffusion lenses 3 densely formed on the inner surface and which closes the front opening of the back cover 1. A substrate 6 on which a large number of light emitting diodes 5 are mounted in a matrix at predetermined intervals is disposed inside, and when the light emitted from each light emitting diode 5 passes through the front lens 2, it is absorbed by the diffuser lens 3. It was designed to spread by spreading it.

[Problem that the invention seeks to solve]

By the way, in the case of a light emitting diode 5, especially one molded with highly transparent resin 8 such as epoxy resin in order to shield and protect the semiconductor chip 7 from the outside air, the tip of the resin 8 itself is formed into a dome shape to improve the directionality of light. Since the light emitting diode 5
Although the axial direction of the front lens 2 is illuminated most brightly and the light is diffused by the diffusion lens 3, a difference in brightness occurs in the front lens 2, which poses a problem in terms of uniform illumination. Therefore, it may be possible to increase the number of light emitting diodes 5, but in that case, not only will it cause an increase in costs, but if they are placed too close together, the amount of light emitted will decrease due to heat generation between the diodes.
Another problem arises in that the expected brightness cannot be obtained.

In addition, since the semiconductor chip 7 is usually placed near the focal position of the dome portion or shifted from the focal position toward the substrate 6 in order to improve the directivity of the light, the light emitted from the light emitting diode 5 out of the light emitted from the semiconductor chip 7 is The disadvantage is that the light emitted diagonally forward at a large angle with respect to the axis does not pass through the dome portion and is not effectively utilized for illuminating the front lens 2.

Furthermore, since the light emitting diode in which the semiconductor chip 7 is simply mounted on the substrate 6 without being molded with the resin 8 constitutes a point light source, it is brightest around the optical axis and becomes darker as it moves away from the optical axis, providing uniform illumination. was difficult.

[Means for solving problems]

The lighting device according to the present invention has been made in view of the above-mentioned points, and includes molding a semiconductor chip of each light emitting diode with a transparent resin, and a spherical lens portion corresponding to the semiconductor chip on the front surface of the transparent resin. an inner lens in which a large number of fisheye condensing lenses are formed corresponding to each light emitting diode is disposed in front of the transparent resin, and an outer lens having a large number of diffusing lenses formed on the inner surface. A lens is disposed in front of the inner lens, and the semiconductor chip is positioned in front of the focal point of the spherical lens portion.

[Function] In the present invention, since the semiconductor chip is placed in front of the focal point of the spherical lens portion, the solid angle of the light that passes through the spherical lens portion among the light emitted from the chip is large; More light can be used effectively and the area ahead can be brightly illuminated. Furthermore, since the fisheye condensing lens converts a point light source into a surface light source, it reduces the directivity of the light emission output and prevents the occurrence of brightness differences.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

FIG. 1 is a sectional view of a main part showing an embodiment of the illumination device according to the present invention applied to a tail light of an automobile, and FIG. 2 is a perspective view of an inner lens. In these figures, the taillight 10 has a frame 1 with open front and rear surfaces.
2, an outer lens 13 that closes the front opening of the frame 12, and a substrate 14 that closes the rear opening of the frame 12, and these constitute the lamp body 11. Inside the lamp body 11, there is an inner lens 15, a large number of light emitting diodes 16 disposed on the inner surface of the substrate 14, and a diode defining member 1.
7th grade is installed.

The outer lens 13 is made of translucent resin or glass colored in a predetermined color, and on its inner surface, a diffusion lens 18 consisting of a large number of small convex lenses is densely formed.

The inner lens 15 is made of transparent or light-transmitting resin, and a large number of fisheye condensing lenses 19 are integrally formed on the surface thereof. The fisheye condensing lens 19 is the inner lens 1
As shown in FIG. 2, the light from the light emitting diode 16 transmitted through the light emitting diode 16 is controlled to be refracted into a substantially parallel beam, and as shown in FIG. Consists of lenses.

Each of the light emitting diodes 16 is mounted on the substrate 14 in correspondence with each of the fisheye condensing lenses 19 of the inner lens 15, and the semiconductor chip 2
1. Consists of a pair of lead wires 22, 23, a gold wire 24, etc., with one lead wire 22 and the semiconductor chip 21
A reflecting plate 25, which is formed of a good conductor and has a substantially dish shape, is interposed between the semiconductor chip 21 and the reflecting plate 25, which is formed of a good conductor and reflects diagonally backward light emitted from the semiconductor chip 21 forward. The semiconductor chip 21 and the other lead wire 23 are connected by a gold wire 24, and the pair of lead wires 22 and 23 are connected to the electric circuit of the substrate 14, respectively.

The diode defining member 17 is integrally formed of opaque synthetic resin, and has a large number of diode accommodating portions 28 in which each of the light emitting diodes 16 is individually defined and accommodated. Diode storage section 2
Reference numeral 8 consists of a tapered through hole that opens on the front and back surfaces of the diode defining member 17, and the inner wall surface has a reflective surface by vapor deposition of aluminum, coating with paint with excellent reflective properties, pasting of aluminum foil, etc. is forming. In addition, each diode storage section 28 is equipped with a transparent resin 30.
is filled to mold the light emitting diode 16. Epoxy resin or the like is used as the resin 30, and the surface thereof is bulged into a substantially hemispherical shape to form a spherical lens portion 31. The semiconductor chip 21 is located in front of the focal point P of the lens portion 31.

In the tail light 10 having such a configuration, the light directed forward out of the light emitted from the semiconductor chip 21 passes through the resin 30 and the inner lens 15 in sequence, and illuminates the outer lens 13. At this time, the light is refracted by the spherical lens part 31 of the resin 30 toward the center of the lens part 31, and further refracted by the fisheye condensing lens 19 of the inner lens 15, so that it becomes approximately parallel light. The light is directed forward and diffused by the diffusion lens 18 of the outer lens 13 to obtain a desired light distribution.

Here, if the semiconductor chip 21 is placed in front of the focal point P of the spherical lens part 31 as shown by the solid line in FIG. It can be set larger than the solid angle θ ₁ of light transmitted through the lens portion 31 when the semiconductor chip is placed at the P position. Therefore, since the amount of light that passes through the spherical lens portion 31 and goes forward increases, there is less loss of light, and the outer lens 13 can be illuminated more brightly.

Further, even if the light emitting diode 16 itself is a point light source, when the light passes through the spherical lens section 31 and the fisheye condensing lens section 19, it is emitted from the entire surface and goes toward the outer lens 13, so that the taillight is 10
When viewed from the front, the light emitted from the light emitting diode 16 shines in a planar shape, making it appear as if it were a planar light source. As a result, the directivity of the light emission output is reduced and the difference in brightness is reduced, so that the entire surface of the outer lens 13 is illuminated with substantially uniform brightness.

Furthermore, since each light emitting diode 16 is separated from other light emitting diodes by the diode defining member 17, the light emitting performance of the diodes does not deteriorate due to heat generation between the diodes, allowing close arrangement.

FIG. 4 is a sectional view of a main part showing another embodiment of the present invention. This embodiment is constructed by mounting a large number of light emitting diodes 5 on a substrate 14, each having a semiconductor chip 7 molded with a transparent resin 8 as an envelope, similar to the conventional structure shown in FIG. The distal end surface of the transparent resin 8 is formed into a dome shape, thereby forming a spherical lens portion 40. However, the semiconductor chip 7 is located in front of the focal point P of the lens portion 40.
The light emitting diode 5 of the conventional structure is different in that the light emitting diode 5 has a conventional structure. Further, in this embodiment, the diode defining member 17 shown in the embodiment in FIG.
It goes without saying that it is desirable to use 7. In addition, 42 is a resistor for diode lighting.

It will be obvious that even in this configuration, since the semiconductor chip 7 is placed in front of the focal point P position of the spherical lens portion 40, the same effects as in the above embodiment can be obtained.

〔Effect of the invention〕

As explained above, the lighting device according to the present invention includes:
A spherical lens part is integrally formed on the front surface of the transparent resin that molds the light emitting diode, and the semiconductor chip of the diode is placed in front of the focal point of this lens part, so that the light that passes through the spherical lens part is In other words, the amount of light that passes through the lens portion can be increased. Therefore, the loss of light is reduced and the illumination effect can be improved. In addition, an inner lens formed of a large number of fisheye condensing lenses corresponding to each diode is arranged between the outer lens and the light emitting diode, and the fisheye condensing lens effectively converts the light emitting diode from a surface light source. Since it is converted into a surface light source, the entire surface of the outer lens can be illuminated with almost uniform brightness.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of the present invention applied to a tail light of an automobile, FIG. 2 is a perspective view of an inner lens, and FIG. 3 is a diagram for explaining the effects of the present invention. FIG. 4 is a sectional view of a main part showing another embodiment of the present invention, and FIG. 5 is a sectional view of a main part showing a conventional example of a lighting device. 1... Back cover, 5... Light emitting diode,
6...Substrate, 7...Semiconductor chip, 8...Transparent resin, 11...Lamp body, 13...Outer lens, 1
4...Substrate, 15...Inner lens, 16...
Light emitting diode, 17... diode defining member,
18...Diffusion lens, 19...Fisheye condensing lens,
30...Transparent resin, 31...Spherical lens portion.

Claims (1)

[Claims] 1. In a lighting device using a large number of light emitting diodes as a light source, the semiconductor chips of each of the light emitting diodes are molded with transparent resin, and a spherical lens portion is integrally formed on the front surface of the transparent resin in correspondence with the semiconductor chips. and in front of the transparent resin,
An inner lens is disposed in which a number of fisheye condensing lenses are formed corresponding to each light emitting diode, and an outer lens having a number of diffusing lenses formed on the inner surface is disposed in front of the inner lens. An illumination device characterized in that the semiconductor chip is disposed in front of a focal point of the spherical lens portion.