JPS62108584A - Light-emitting diode lighting appliance - Google Patents

Abstract

PURPOSE:To decrease emission spots on the surface of a front lens by mounting an inner lens group consisting of a first lens synthetically functioning as a concave lens and a second lens, which has the same axis and collectively takes a convex shape by Fresnel cut, etc., in succession from the side of a light- emitting diode. CONSTITUTION:A light-emitting diode 1 is fitted to a printed substrate 2, and a front lens 3 is set up on the front side of the diode 1. An inner lens group 4 composed of a first lens 4a, which has the same axis as an optical axis for the light-emitting diode and is cut in a concave lens manner, and a second lens 4b, which has an optical axis approximately coinciding with the optical axis for the first lens 4a and is formed to a convex lens by using a cut means such as one for a Fresnel lens, is mounted between the light-emitting diode 1 and the front lens 3. The first lens widens the angle of radiation of narrow beams from the light-emitting diode, and the second lens changes the beams having the widened angle of radiation into parallel beams. Accordingly, beams are projected uniformly to the front lens, thus removing emission spots on said front lens surface.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention aims to further improve the reliability of transportation signal lights, such as traffic lights and automobile taillights, which are solid-state light sources. 'It improves the luminescent ring that tends to occur when using a light emitting diode as a light source.

[Prior Art] Conventionally, in this type of lamp, the light emitted by the light emitting diode used as the light source has a sharp and narrow directionality, so no matter how carefully the front lens is cut, It is difficult to emit light uniformly over the entire surface of the front lens, and a method for solving this problem is to arrange the light emitting diode 1 as close to the printed circuit board 2 as physically possible, as shown in FIG. The only solution is to reduce the luminous ring that falls on the surface of the front lens 3.

[Problems to be Solved by the Invention] However, in the conventional method of solving the luminous ring on the surface of the front lens, firstly, the luminous ring is arranged as closely as physically possible as explained above. However, even if the light emitting diode is provided with a light emitting diode, it is still not sufficient to solve the problem, and this problem arises from the fact that light is concentrated on the optical axis of the light emitting diode.

Secondly, arranging the light emitting diodes in close contact with each other causes the problem of heat generation, which requires heat dissipation means such as a heat sink, and especially when the light emitting diodes in the center The concentration of heat generated greatly increases the risk of thermal damage. This is despite using the same light emitting diode light source.
There is a quality control problem in that there is a difference in reliability between those installed on the periphery and those installed in the center, and furthermore, the center of the lamp gets very hot. Due to the difference in luminous efficiency caused by heat in the light emitting diodes, the central part becomes dark, and in addition to the luminescent spots caused by the sharp directivity of the light emitting diodes explained above, luminescent spots in a large area also occur in the lamp. There are also new problems that arise with
Thirdly, in order to eliminate luminous spots, for example, it is necessary to use more light emitting diodes than the originally required illumination intensity, which is an economical efficiency problem, and the resulting power consumption is higher than necessary. This resulted in the problem of an increase in

[Means for Solving the Problems] The present invention provides a light emitting diode lamp having a front lens for determining alignment characteristics and one or more light emitting diodes as a light source as a specific means for solving the above problems. , a concave lens cut coaxially provided with the optical axis of the light emitting diode at an intermediate position between the front lens and the light emitting diode, and a first lens that is a concave lens overall, and a first lens that is also coaxial and a Fresnel cut, etc. By providing a light emitting diode lamp characterized in that an inner lens group consisting of a convex second lens is sequentially provided from the light emitting diode side, the front lens can be used even with the minimum number of light emitting diodes. This is to eliminate the luminescent spots on the surface and solve the above-mentioned conventional problems.

[Example] Next, the present invention will be described in detail based on an example shown in the drawings. In order to facilitate understanding, the same parts as in the conventional example will be described using the same reference numerals.

In the one shown in FIG. 1, the light emitting diode 1 is 11! ] This is the most basic embodiment of the present invention. As in the conventional example, a light emitting diode 1 is attached to a printed circuit board 2, and a front lens 3 is provided on the front side of the light emitting diode 1.A concave lens cut is made from the light emitting diode 1 side coaxially with the optical axis of the light emitting diode. The first lens 4a is formed into a convex lens using a lens cutting means called, for example, a Fresnel lens, with an optical axis substantially coinciding with the optical axis of the first lens 4a. An inner lens group 4 consisting of two lenses 4b is provided between the light emitting diode 1 and the front lens 3. To explain the criteria for designing the lens group 4 in this poem, the first lens 4a transmits the light from the light emitting diode having the narrow light emission angle described above to at least the entire effective surface of the front lens 3. The concave lens cut is necessary to widen the radiation angle to cover the radiation angle, and the convex lens of the second lens is a convex lens cut necessary to make the radiation angle expanded by the first lens into a parallel ray.

FIG. 2 shows an example in which the invention described above is applied to a lamp having a plurality of light emitting diodes 1, and one element is illustrated to avoid complicating the drawing. In such a case, the range that one light emitting diode 1 can receive is first determined based on the brightness required of the lamp. This can be easily calculated by dividing the effective luminous flux of the light emitting diodes 1 by the required illuminance, and thereby the required number of light emitting diodes 1 and the spacing between them can be easily determined. The light emitting diodes 1 are arranged on the printed circuit board 2 at predetermined numbers and intervals using the above method, and the first lens 5a is provided on the optical axis of the light emitting diodes 1. The first lens 4a (FIG. 1) having the same shape as shown in FIG. A second lens 5b is provided on the third side, and the second lens 5b also corresponds to the number and spacing of the light emitting diodes 1 and is optically coaxial. The inner lens 5 is configured by repeating the elements described above a necessary number of times.

[Function] According to the present invention, the first lens, which is a concave lens, widens the narrow radiation angle of the light of the light emitting diode coaxially with the optical axis of the light emitting diode, which is the light source, and the light of the widened radiation angle is made into parallel rays. By providing an inner lens group consisting of a second lens, which is a convex lens, between the light emitting diode and the front lens, the angle of radiation from one light emitting diode is widened, and parallel light is uniformly projected onto the front lens. This eliminates luminescent spots on the front lens surface, similar to a lighting device that uses a light bulb and a reflecting mirror, for example.

[Effects of the Invention] As explained in detail above, by providing the inner lens group between the light emitting diode that is the light source and the front lens according to the present invention, luminous spots on the front lens surface can be eliminated and the use thereof can be improved. It also makes it possible to reduce the number of light emitting diodes, solves the problem of reliability due to shortened lifespan due to heat generation, and further improves practicality by optimizing current consumption. This has an excellent effect on improving reliability.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of a light emitting diode lamp according to the present invention, and FIG. 2 is a sectional view showing main parts of another embodiment.
FIG. 3 is a sectional view showing a conventional example. 1...Light emitting diode 2...Printed circuit board 3...
・Front lens 4a, 5a...First lens 4b, 5b...Second lens 4.5...Inner lens Patent applicant Stanley Electric Co., Ltd. Figure 1 Figure 2! ! I

Claims (1)

[Claims] In a light emitting diode lamp having a front lens for determining orientation characteristics and one or more light emitting diodes serving as a light source, a concave lens cut provided coaxially with the optical axis of the light emitting diode at a position intermediate between the front lens and the light emitting diode. Therefore, overall, the first lens is a concave lens,
A light emitting diode lamp characterized in that an inner lens group consisting of a second lens which is also coaxial and has a generally convex shape due to a Fresnel cut or the like is sequentially provided from the light emitting diode side.