JPH0374444B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a lighting device suitable for use in a vehicle lamp, and particularly in a lighting device using a large number of light emitting diodes as a light source, the front surface of the surface plate is uniformly distributed. This invention relates to a lighting device that illuminates the room and improves the lighting effect.

[Conventional technology]

In recent years, with the development of semiconductor technology, high-brightness light-emitting diodes have been developed, and they are now available at low prices, which has led to the use of vehicular lighting, especially brake lights,
Consideration is now being given to using it instead of light bulbs as a light source for taillights, etc., and one example is the first
The one shown in Figure 0 is known. Namely, numeral 1 is a front lens having a densely formed diffuser lens 2 made up of many small convex lenses on its inner surface, and numeral 3 is a front lens disposed behind the front lens 1, with a large number of light emitting diodes 4 arranged at predetermined intervals on the surface. The board 5 is mounted in a matrix, and is a back cover that forms a lamp body together with the front lens 1. Each light emitting diode 4
The light emitted from the front lens 1 passes through the front lens 1 and is diffused by the diffusing lens 2 when illuminating the lens.

[Problem that the invention seeks to solve]

By the way, in the case of a light emitting diode 4, especially one molded with a highly transparent resin 4b such as epoxy resin in order to shield and protect the semiconductor chip 4a from the outside air, the tip of the resin 4b itself is formed into a dome shape to improve the directionality of light. Since the axial direction of the light emitting diode 4 is increased, the illumination is brightest in the axial direction of the light emitting diode 4, and even though the light is diffused by the diffusing lens 2, a difference in brightness occurs in the front lens 1, which causes a problem in uniform illumination. Therefore, it may be possible to increase the number of light emitting diodes 4, but in that case, this will not only 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, and the expected brightness will not be obtained. Another problem arises:

[Means for solving problems]

The lighting device according to the present invention has been made in view of the above-mentioned points, and includes a light-transmitting surface plate,
an inner lens having a large number of fisheye condensing lenses formed on its surface and disposed behind the surface plate; and a large number of light emitting diodes disposed behind the inner lens and corresponding to each of the fisheye condensing lenses on its surface. is mounted on the substrate, and an intermediate lens disposed between the surface plate and the inner lens, and the intermediate lens is formed of a protrusion or a long groove each having a substantially semicircular cross-sectional shape, and the intermediate lens is formed of a protrusion or a long groove having a substantially semicircular cross-sectional shape in the longitudinal direction thereof. A large number of first float-shaped lenses are arranged in parallel in parallel with each other, and the first float-shaped lenses are arranged in parallel in a large number in parallel with the longitudinal direction of the protrusions or long grooves, each of which has a substantially semicircular cross-sectional shape. and a second float-shaped lens positioned perpendicularly to each other behind the lens.

[Effect]

In the present invention, the fisheye condensing lens condenses the light emitted from the light emitting diode into a light beam substantially parallel to the optical axis, thereby converting a point light source into a surface light source. The intermediate lens is
By diffusing the parallel light beams that pass through the fisheye condenser lens, the intensity of the light is made uniform.

〔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 present invention applied to a taillight of a car, Fig. 2 is an enlarged sectional view of a light emitting diode, and Fig. 3 is a perspective view of an inner lens and an intermediate lens. . In these figures, the taillight 10 includes a back cover 12 that forms a lamp body 11, and a surface plate 13 that closes the front opening of the back cover 12. Inside the taillight 10, an inner lens 14 and a large number of light emitting diodes 15 are arranged in a matrix. A substrate 16 mounted on the substrate 16, an intermediate lens 1 disposed between the surface plate 13 and the inner lens 14.
7th grade is installed.

The surface plate 13 is made of a transparent or light-transmitting resin plate, and both the front and back surfaces thereof are formed into smooth surfaces. In this case, the surface plate 13 is colored in a predetermined color such as red to constitute a filter.

The inner lens 14 is made of a transparent or light-transmitting resin, and a large number of fisheye condensing lenses 19 are integrally formed on the surface thereof. Each of the fisheye condensing lenses 19 is constituted by a hemispherical spherical lens having a substantially rectangular outline with substantially equal sides on the bottom.

As shown in FIG. 2, each of the light emitting diodes 15 is mounted on the surface of the substrate 16 in correspondence with each of the fisheye condensing lenses 19, and includes a semiconductor chip 21, a transparent resin 22, and a pair of leads. line 2
3a, 23b, gold wire 24, etc. The transparent resin 22 is formed of epoxy resin or the like into a cylindrical shape, molds the semiconductor chip 21, part of the pair of lead wires 23a and 23b, and the gold wire 24, and faces the back surface of the inner lens 14. The tip end surface is formed into a flat surface and constitutes a diffusing surface 26 that diffuses the light A exiting from the semiconductor chip 21 and directed forward. If the end surface of the transparent resin 22 is dome-shaped, it has a lens function and condenses light, resulting in a small diffusion angle, but if it is a flat surface 26, the light A is directed outward as shown in FIG. Since the light is refracted, the angle of diffusion is large, and thereby the size I of the fisheye condensing lens 19 can be changed. The semiconductor chip 21 has one lead wire 23
A substantially dish-shaped chip mounting portion 27 provided at the inner end of a.
The lead wire 23b is placed and fixed thereon, and is connected to the inner end of the other lead wire 23b by the gold wire 24. The outer ends of each lead wire 23a, 23b are connected to the electric circuit of the board 16.

The intermediate lens 17 is integrally formed of transparent resin, and has a first float lens 29 formed on its front surface and a second float lens 30 formed on its back surface. The first float-like lens 29 is composed of a large number of small semi-cylindrical protrusions 29a, each of which extends over almost the entire length of the intermediate lens 17 in the longitudinal direction and is closely arranged in parallel in the width direction. Similarly, the second float-like lens 29 is composed of a large number of small semi-cylindrical protrusions 30a, each of which extends over almost the entire length of the intermediate lens 17 in the width direction and is closely arranged in parallel in the longitudinal direction. Therefore, the first float lens 29 and the second float lens 30 are orthogonal to each other.

In the taillight 10 having such a configuration, out of the light emitted from the semiconductor chip 21, light A is directed forward and emitted to the outside from the diffusion surface 26 of the transparent resin 22.
is refracted and diffused at the diffusion surface 26. Therefore, this diffused light A almost uniformly illuminates the back surface of the inner lens 14, which is sufficient to cover the entire area I of the fisheye condensing lens 19 corresponding to the light emitting diode 15, and when passing through the inner lens 14, the The light is condensed by the fisheye condensing lens 19 and becomes a substantially parallel light beam A ₁ toward the front. Since this parallel ray _A1 is emitted from the entire surface of the fisheye condensing lens 19,
The light emitting diode 15 as a point light source is converted into a surface light source. When the parallel light beam A ₁ passes through the intermediate lens 17, it is diffused twice in orthogonal directions by the second and first float lenses 30 and 29, and then passes through the surface plate 13 and exits to the outside. do.

Thus, according to the taillight having such a configuration, the light from the light emitting diode 15 is transmitted through the transparent resin 2.
the second diffusion surface 26, the fisheye condensing lens 19, and the first
Since the second float lenses 29 and 30 diffuse and condense the light to convert the point light source into a surface light source, the directivity of the light emitting output of the diode 15 itself can be weakened. Therefore, the occurrence of differences in brightness and darkness can be prevented, and the entire surface of the surface plate 13 can be illuminated with substantially uniform brightness. Furthermore, each light emitting diode 15 has a fisheye condenser lens 19.
Since the diodes are arranged in correspondence with each other and a sufficient distance is maintained between the diodes, there is no reduction in light emitting performance due to heat generation between the diodes.

FIG. 4 is a front view of a light emitting diode showing another embodiment of the present invention. In this example, transparent resin 22
The only difference from the above embodiment is that the distal end surface facing the inner lens is a hemispherical diffusing surface 35, and the semiconductor chip 21 is disposed at or near the center O, and all other configurations are the same.

In the light emitting diode 15 having such a configuration, the light A ₃ that comes out from the semiconductor chip 21 and goes toward the spherical diffusing surface 35 is not reflected or refracted by the diffusing surface 35 and is all emitted straight to the outside. , it has the advantage of having less light loss and enabling even brighter illumination.

Here, as shown in FIG.
By arranging the chip 21 at a predetermined distance below the center O of the spherical diffusing surface 35, all of the light _A8 that comes out of the chip 21 and passes through the diffusing surface 35 can be efficiently guided to the corresponding fisheye condenser lens 19. can.

FIG. 6 is a sectional view of main parts showing another embodiment of the present invention, and FIG. 6 is a perspective view of main components. This embodiment differs from the embodiment shown in FIG. 1 in that a light shielding member 40 is interposed between the inner lens 14 and the substrate 16.

The light shielding member 40 is integrally formed of opaque synthetic resin, and has a large number of diode storage portions 41 that individually and independently store each light emitting diode 15 in a defined manner. Each diode accommodating portion 41 is formed of an inverted trapezoidal transparent structure that opens on the front and back surfaces of the light shielding member 40, and the opening on the front side has approximately the same size as the outline shape of the fisheye condensing lens 19. The wall surface 42 that partitions each diode storage section 41 forms a reflective surface by pasting aluminum foil or the like.

Of the light emitted from the semiconductor chip 21 and directed toward the wall surface 42 of the diode storage section 41 in an oblique direction, a portion _A4 thereof is reflected by the wall surface 42 in the direction of the inner lens 14, and is reflected by the wall surface 42 toward the inner lens 14.
7 and contributes to the illumination of the surface plate 13.
Therefore, light loss is reduced and the lighting effect is further improved.

In this case, among the light that is emitted diagonally forward, the light that is emitted at a certain angle is brighter than other light rays, and this bright light is the inner lens 19,
When the light passes through the intermediate lens 17 and the front plate 13 and is emitted diagonally forward, it shines brightly and dazzles, but if the light shielding member 40 is provided as in this embodiment and the light is reflected by the wall surface 42, as shown in FIG. The glare can be reduced compared to the embodiment, and visibility from diagonally ahead is facilitated. Furthermore, if the wall surface 42 is made a part of a paraboloid of revolution and the light emitting diode 15 is positioned at its focal point, the reflected light reflected by the wall surface 42 will be approximately parallel to the axis of the paraboloid of revolution. Since the light is directed forward as parallel rays, it is reliably focused by the fisheye condensing lens 19 corresponding to the diode, and does not enter into other adjacent fisheye condensing lenses.

FIG. 8 is a sectional view of a main part showing another embodiment of the light shielding member. In this embodiment, a light shielding member 40 is integrally provided on the back surface of the inner lens 14 to define each light emitting diode 15. Light shielding member 40
has various diode housing portions 41 formed in a lattice shape with orthogonal side wall plates and open to the rear. Each diode storage section 41 corresponds to each fisheye condenser lens 19, and a light emitting diode 15 is inserted into the center thereof. An appropriate gap is set between the light shielding member 40 and the substrate 16, which improves ventilation and allows the light emitting diode 1 to
The heat dissipation effect of 5 is improved.

FIG. 9 is a perspective view of main parts of a surface plate and an intermediate lens showing still another embodiment of the present invention. In this embodiment, the first and second float lenses 29 and 30 of the intermediate lens 17 are connected to the surface plate 13 and the intermediate lens 17.
The front plate 13 has half the function of an intermediate lens. The first float lens 29 is formed on the back surface of the front plate 13, and the second float lens 30 is formed on the intermediate lens 1.
7 is formed so as to be perpendicular to the first float lens 29 . It is assumed that the other structures are the same as those of the embodiment shown in FIG. 1 or the embodiment shown in FIG.

It is clear that the same effects as in the above embodiment can be obtained also in such a configuration.

Incidentally, in each of the embodiments of the present invention, the first and second float-like lenses 29 and 30 have been described as convex lenses consisting of approximately semi-cylindrical long grooves. The same effect can be obtained even with a concave lens.

〔Effect of the invention〕

As explained above, according to the lighting device according to the present invention, the fisheye condensing lens of the inner lens converts the light emitted from the light emitting diode into parallel rays substantially parallel to the optical axis, thereby converting a point light source into a surface light source. Moreover, since the light is diffused twice in orthogonal directions by the first and second float lenses of the intermediate lens, the directivity of the light emission output can be weakened. Therefore, the entire surface of the top plate can be illuminated with substantially uniform brightness, improving the illumination effect. In addition, there is no need to increase the number of light emitting diodes, and therefore the effect of preventing the heat generation of the diodes from adversely affecting the amount of light emitted is very large.

[Brief explanation of drawings]

Fig. 1 is a sectional view of essential parts showing an embodiment of the present invention applied to an automobile taillight, Fig. 2 is an enlarged sectional view of a light emitting diode, Fig. 3 is a perspective view of an inner lens and an intermediate lens, and Fig. 3 is a perspective view of an inner lens and an intermediate lens. 4 and 5 are front views showing other embodiments of the light emitting diode, respectively;
FIG. 6 is a sectional view of main parts showing another embodiment of the present invention;
FIG. 7 is a perspective view of the main components, FIG. 8 is a sectional view of main parts showing another embodiment of the light shielding member, and FIG. 9 is a main part of a surface plate and intermediate lens showing another embodiment of the present invention. The perspective view and FIG. 10 are sectional views showing an example of a conventional device. 10...tail light, 12...back cover, 13...
... Surface plate, 14 ... Inner lens, 15 ... Light emitting diode, 16 ... Substrate, 17 ... Intermediate lens, 19 ... Fisheye condensing lens, 21 ... Semiconductor chip, 22 ... Transparent resin, 29 ... ...first float lens, 30...second float lens,
40... Light shielding member.

Claims (1)

[Claims] 1. A surface plate that is translucent and closes the front opening of the back cover, an inner lens having a large number of fisheye condensing lenses formed on its surface and placed behind the surface plate, and a lens located behind the inner lens. a plurality of light emitting diodes disposed on the surface of the substrate and corresponding to each of the fisheye condensing lenses, and an intermediate lens disposed between the surface plate and the inner lens. The intermediate lens includes a plurality of first float-shaped lenses each having a substantially semicircular cross-sectional shape and a plurality of first float-like lenses arranged in parallel in parallel with the longitudinal direction, each of which is a protrusion or a long groove having a substantially semicircular cross-sectional shape. An illumination device comprising a plurality of second float-like lenses made of protrusions or long grooves arranged parallel to each other in parallel with the longitudinal direction thereof, and located behind the first float-like lenses so as to be orthogonal to each other. Device.