JP2006072874A - Signal light - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the combination of an optical lens and a micro lens in a signal light using an LED element as a light source for increasing the light output from each LED element and realizing uniform light emission with, even illuminance causing no dark part in a gap between the LED elements, when the number of the LED elements is reduced. <P>SOLUTION: This signal light is provided with a light source, constructed of a plurality of LED elements 3 arranged on a plane and an optical lens 41, arranged correspondingly in front of the respective LED elements 3. A group of micro lenses, which are arranged on the light emission face 41d side of the optical lens 41, integrally with it or separately from it for light distribution control, is arranged; and the light emission face 41d of the optical lens 41 is formed into a shape returning light reaching the light emission face 41d through the vicinity of an inflection point between a convex face 41a and a concave face 41b into parallel light. In this way, light within a strong light distribution area of the LED element can be distributed to a dark part generated due to the lens shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a signal lamp using a plurality of LED elements as light sources.

  Conventionally, there is a traffic signal lamp in which a convex lens for condensing is arranged in front of a bullet-type LED element in order to efficiently collect light emitted from a plurality of arranged LED elements. In this type of signal lamp, since it is out of the light distribution at a short distance from the signal lamp, it is difficult to visually recognize the light emitted from the signal lamp. In addition, when external light such as western sunlight (sunlight) is condensed on each LED element by the lens and is specularly reflected on the LED element mounting substrate surface, etc., the visibility of lighting deteriorates and it is not lit. , It may appear to be lit (this is called pseudo-lighting). In order to solve this problem, it is known to provide a light diffusion prism separately or integrally with the lens (for example, see Patent Document 1).

In addition, it is known to arrange a lens with a lens cut portion corresponding to and facing each other on the front surface of the LED element so that light emitted from each LED element can be efficiently refracted and utilized. (For example, refer to Patent Document 2).
JP 2002-183891 A Japanese Unexamined Patent Publication No. 63-23604

  By the way, the light emission diameter as a signal lamp is approximately 250 mm to 350 mm, and it is necessary to emit light within the light emission diameter as uniformly as possible while maintaining a predetermined luminous intensity. Even in the case of a signal lamp having a prism, when the bullet-type LED elements are closely arranged, the number of LED elements increases, resulting in a high cost, and a dark portion is generated in the light emission gap. When the number of LED elements is reduced and the light output of each LED element is increased, the dark part of the gap between the LED elements becomes more conspicuous. Further, even in a signal lamp having a lens as disclosed in Patent Document 2, there is still a dark part in the gap between the lenses, and when the light distribution is controlled, the luminance unevenness of light emission increases on the exit side of each lens. . In particular, due to the lens shape and the light distribution of the LED elements, there is a problem that a weak light emitting region is formed, for example, a dark portion is formed in an annular shape.

  The present invention solves the above problem, and by devising a combination of an optical lens and a microlens, even if the light output of each LED element is increased and the number of LED elements is reduced, the gap between the LED elements is reduced. Therefore, it is an object of the present invention to provide a signal lamp capable of realizing uniform light emission and preventing uneven luminance of light emission due to the lens shape and the light distribution of the LED elements.

  In order to achieve the above-mentioned object, the present invention provides a signal lamp including a light source composed of a plurality of LED elements arranged in a planar shape and an optical lens arranged corresponding to the front of each LED element. In addition, a micro lens group in which a plurality of micro lenses for light distribution control are arranged separately or separately from the lens is provided, and the optical lens includes a convex surface formed facing the LED element, and the convex surface. A concave surface formed so as to surround the LED element at the peripheral edge of the LED, a reflective surface that totally reflects light from the LED element that has transmitted through the concave surface, and an output surface that emits light from the convex surface and the reflective surface. When the light distribution of the LED element is Lambert distribution, the lens for returning the light reaching the exit surface through the convex surface of the optical lens and the inflection point between the convex surface and the concave surface to parallel light on the exit surface The shape was provided on the exit surface Than it is. Further, the present invention provides a signal lamp including a light source composed of a plurality of LED elements arranged in a planar shape and an optical lens arranged corresponding to the front of each LED element, and the lens on the light exit surface side of the optical lens. A microlens group comprising a plurality of microlenses for controlling light distribution is provided integrally or separately, and the optical lens has a convex surface formed facing the LED element and an LED on the peripheral edge of the convex surface. The LED element having a concave surface formed so as to surround the element, a reflective surface that totally reflects light from the LED element that has transmitted through the concave surface, and an output surface that emits light from the convex surface and the reflective surface; When the light distribution is strong to the side, the reflecting surface of the optical lens is formed so that the reflected light passes through a weak light distribution region of the emitting surface.

  According to the present invention, the light emitting area from each LED element is enlarged by the optical lens and the light is distributed by the micro lens group, so that the light output of each LED element is increased and the number of LED elements is reduced. However, it is difficult for dark portions to occur in the gaps between the optical lenses, the unevenness of the luminance distribution is reduced, and uniform light emission is possible. Moreover, the light that reaches the exit surface through the vicinity of the inflection point between the convex surface and the concave surface of the optical lens is converted back to parallel light on the exit surface of the lens, so that the light in the strong Lambertian distribution of the LED element It is possible to distribute light to the dark part caused by the light. As a result, the luminance unevenness of light emission can be improved, and uniform light emission can be achieved. In addition, since the light reflected by the reflecting surface of the optical lens passes through a weak light distribution region of the emitting surface due to the optical lens shape, a strong light distribution near the side of the LED element can be effectively used. Equivalent effects can be obtained.

  Hereinafter, signal lights according to embodiments of the present invention will be described with reference to the drawings. 1 shows the configuration of the signal lamp, FIG. 2 conceptually shows the front configuration of the main part of the signal lamp, and FIG. 3 conceptually shows the main configuration of the signal lamp. In FIG. 1, a signal lamp 1 is provided corresponding to each LED element 3 on a front surface of the light source, and a light source composed of a plurality of LED elements 3 arranged and mounted in a circle in front view on a circuit board 2 on which circuit wiring is applied. The optical lens plate 4, a black back body 5 made of a resin or a metal material, a transparent or colored front cover 6 made of a resin material having ultraviolet resistance, and a power circuit 7. The power supply circuit 7 receives power supply from the power supply line 8 and supplies power for lighting the light source through the wiring 9 to the circuit of the substrate 2. The signal light is composed of three colors of red, blue, and yellow, but only one of them is shown here.

  The optical lens plate 4 is made of a resin material such as transparent or colored acrylic or glass, and a plurality of optical lenses 41 arranged corresponding to the front of each LED element 3, and the lens 41 is integrated or separated on the exit surface side. And a microlens group including a plurality of microlenses 42 for light distribution control formed on the body. When each LED element 3 is referred to as a unit LED, each optical lens 41 is referred to as a unit lens. The light emitting area from each LED element 3 is expanded by each optical lens 41. In this embodiment, as shown in FIGS. 2 and 3, each optical lens 41 has a regular hexagonal shape when viewed from the front, and the gap between the lenses is integrally formed of a resin so as to suppress the gap as much as possible. As much as possible, the occurrence of dark areas is reduced. Each optical lens 41 is not limited to a regular hexagon. The number of the LED elements 3 may be an appropriate number, for example, 30 to 90. Further, a part of the lens is cut at the outer peripheral portion of the optical lens plate 4 so that the light emitting portion is circular.

  The micro lens group is formed by closely arranging a large number of micro lenses 42 integrally or separately with the optical lens 41, and FIG. 1 shows an example in which the micro lenses 42 are formed on a lens sheet 44 which is a separate member. . The micro lens group has a light distribution function and emits light uniformly, and when viewed from the front, it has no flat part, suppresses reflection of incident western sun, and simulates light emission caused by reflected light. Is preventing.

  FIG. 4 shows a basic configuration of the optical lens 41 according to the present embodiment. This figure shows a lens cross section, but the broken line is omitted (the same applies hereinafter), and the minute lens group provided on the exit surface of the optical lens 41 is also omitted. The optical lens 41 has a rotationally symmetric shape with respect to the optical axis X, and is formed so as to surround the LED element 3 on the convex surface 41a formed at the central portion facing the LED element 3 and the peripheral portion of the convex surface 41a. It has a concave surface 41b, a reflective surface 41c that totally reflects light from the LED element 3 that has passed through the concave surface 41b, and an output surface 41d that intersects the optical axis X perpendicularly. In this specification, the optical lens 41 having such a basic shape is referred to as a hybrid lens. Further, although the light emitting surface 3a of the LED element 3 is planar, the lens shape design is performed based on the point light source A. The LED element 3 is arranged so that the center of the light emitting surface 3a is the position of the point light source A.

  The convex surface 41a of the optical lens 41 is set in a shape such that light incident on this surface of the light from the point light source A becomes a light beam parallel to the optical axis X after incident refraction. The concave surface 41b is a surface that refracts light and guides it to the reflective surface 41c. The angle θ formed by the concave surface 41b and the optical axis X is an angle of 0 ° or more for securing the draft angle of the lens molding die. The shape of the reflecting surface 41c is set so that the light beam totally reflected by this surface becomes light parallel to the optical axis X. The exit surface 41d is a flat surface in this example, and the emitted light becomes parallel light in the case of a point light source (in fact, since the light source has a size, it has a certain extent around the optical axis X). ). A minute lens group (not shown) is provided on the emission surface 41d. L1 indicates a light beam that reaches the outermost periphery of the reflection surface 41c, and the lens aperture is determined so that at least the light beam L1 can be used by the reflection surface 41c.

  FIGS. 5, 6A and 6B show the configuration of the optical lens 41 and the minute lens 42 provided on the exit surface thereof. In FIG. 5, the micro lens 42 is provided integrally with the optical lens 41. The optical lens 41 can be controlled to an arbitrary light distribution by the design of the microlens 42 without changing the basic shape of the hybrid lens, and can be an asymmetric light distribution that distributes light below the horizontal plane required for the signal lamp. At the same time, uniform light emission is possible, and uneven brightness distribution is suppressed. 6A and 6B, the micro lens 42 is provided on the exit surface of the optical lens 41 on a lens sheet 44 (or cover) which is a separate member. In FIGS. 4A and 4B, the surface of the lens sheet 44 on which the microlenses 42 are present is reversed inside and outside. The minute lens group may be provided on a lens sheet that is a separate member from the optical lens 41, or the emission surface of the optical lens 41 may be integrally formed by extrusion.

  Here, with reference to FIG. 7, a description will be given of how luminance unevenness occurs due to the lens shape and the light distribution characteristics of the LED elements when an optical lens to which the present invention is not applied is used. The optical lens 41 is equivalent to that shown in FIG. 4, and when the optical lens 41 is molded, the concave surface 41b needs a taper for pulling out the mold, and because of its shape, it corresponds to the concave surface 41b. A region having a width W in the direction perpendicular to the optical axis X is a portion that does not emit light. If the LED element 3 has a Lambertian light distribution characteristic that is strong in the optical axis X direction and weak in the lateral direction, the LED element 3 emits from the lateral direction, is reflected by the reflecting surface 41c through the concave surface 41b, and is emitted from the emitting surface 41d. The light beam L is weak in light quantity. As described above, a portion that does not emit light and a portion that emits light weakly occur in the vicinity. For this reason, when the emission surface 41d is viewed from the front, an annular dark portion B is generated as shown in FIG. 8, and the uniformity of light emission is greatly impaired.

  Therefore, the signal lamp of the present invention effectively uses the light in the strong light distribution range of the LED element and distributes the light to the dark part of the exit surface due to the shape of the optical lens so that the dark part does not occur on the exit surface of the optical lens. Thus, the luminance unevenness of light emission is improved, and the uniform light emission property is enhanced. First, the case where the light distribution of the LED element is Lambert distribution will be described with reference to FIGS. As described above, the optical lens 41 has the micro lens 42 that enables uniform light emission, but the micro lens 42 is omitted in FIG. FIG. 9 shows a case where the light distribution of the LED element 3 is a general Lambert distribution which is strong in the front direction of the element, and FIG. 10 shows an embodiment of the hybrid optical lens 41 which can improve luminance unevenness in that case. .

  In FIG. 10, the optical lens 41 has a light distribution of the LED element 3 passing through the convex surface 41a at the center of the incident surface (indicated by a thick line) and the vicinity of the inflection point α between the convex surface 41a and the concave surface 41b. A lens upper surface shape 41e (indicated by a thick line) for returning light reaching 41d to parallel light on the output surface 41d is provided on the output surface. By forming the optical lens in this manner, light in a range where the Lambert distribution of the LED element 3 is strong can be distributed to a dark portion where light is not emitted with a direction width W caused by the shape of the optical lens 41. Specifically, the lens shape is designed so that the light beam L refracted through the lens inflection point α reaches the periphery of the end β within the range of the lens upper surface shape 41e. Thereby, the strong range of LED light distribution can be used effectively, luminance unevenness of light emission can be improved, and uniform light emission can be achieved. The concave surface 41b is a surface between the convex surface 41a and the reflective surface 41c, that is, a surface between the inflection point α and another inflection point γ.

  FIG. 11 shows a case where the light distribution of the LED element 3 is a batwing distribution that is strong toward the side (periphery) of the element, and FIGS. 12A and 12B are hybrids that can improve luminance unevenness in that case. An example of the optical lens 41 will be described. The optical lens 41 is formed with a reflection surface 41c (indicated by a thick line) so that the reflected light passes through a weak light distribution region (due to the lens shape) of the emission surface 41d. Of the exit surface 41d, the outer peripheral region, that is, the region where the reflected light from the reflection surface 41c reaches, is formed into a spherical shape 41f (indicated by a thick line) as shown in FIG. 12 (a), or FIG. As shown in FIG. 4, the conical shape is 41 g (indicated by a thick line) so that parallel light is emitted. Thereby, similarly to the above, it is possible to effectively use the strong range of the LED light distribution, improve the luminance unevenness of light emission, and enable uniform light emission. Furthermore, according to such a shape, the moldability of the lens is good, and weight reduction and cost reduction can be realized. In addition, although the output surface 41d shows a planar shape in FIGS. 12 (a) and 12 (b), if these are designed in accordance with the shape of the convex surface 41a, FIGS. 13 (a) (b) and 14 (a). ) As shown in (b), it may be convex or concave.

  As shown in FIG. 13A, when the concave exit surface 41d ′ is used, if the curvature of the convex surface 41a ′ on the incident side is reduced, the same effect as in FIG. It is done. As shown in FIG. 13B, in the case of the convex emission surface 41d ″, the same effect as FIG. 12A can be obtained by increasing the curvature of the convex surface 41a ″ on the incident side.

  Further, as shown in FIG. 14A, in the case of a concave emission surface 41d ', the curvature of the convex surface 41a' is reduced. As shown in FIG. 14B, when the convex emission surface 41d ″ is used, the curvature of the convex surface 41a ″ is increased. By these, the same effect as FIG.12 (b) is acquired.

  The present invention is not limited to the configuration of the above-described embodiment, and various modifications are possible without departing from the spirit of the invention. For example, the optical lens 41 as a hybrid lens does not have a dark portion between the lenses. Any lens shape and arrangement can be employed. Further, the optical lens 41 and the micro lens 42 may be configured to realize a vertically asymmetrical light distribution in which an upward light distribution that is not necessary as a signal lamp is reduced with respect to the front direction of the signal lamp.

The block diagram of the signal lamp which concerns on one Embodiment of this invention. The front view of the principal part of the signal lamp. The perspective view which shows notionally the principal part of the signal lamp. Sectional drawing of the basic composition of the optical lens in the signal lamp. The figure which shows the structure of the micro lens provided in the output surface of an optical lens. (A) and (b) are diagrams showing a configuration different from the above of the microlens. The figure which shows the effect | action of the optical lens which has not applied this invention. The figure which looked at the output surface of the optical lens which has not applied this invention same as the above. The figure which shows the light distribution of LED. Sectional drawing which shows the Example of the optical lens to which this invention is applied. The figure which shows the other light distribution of LED. (A) (b) is sectional drawing which shows the other Example of the optical lens to which this invention is applied. (A) and (b) are sectional drawings which show the modification of the optical lens of Fig.12 (a). (A) and (b) are sectional views showing a modification of the optical lens of FIG. 12 (b).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Signal lamp 3 LED element 4 Optical lens plate 41 Optical lens 41a Convex surface 41b Concave surface 41c Reflective surface 41d Output surface 41e Lens upper surface shape 41f Spherical shape 41g Conical shape 42 Micro lens

Claims (2)

In a signal lamp comprising a light source composed of a plurality of LED elements arranged in a planar shape and an optical lens arranged corresponding to the front of each LED element,
Provided on the exit surface side of the optical lens is a micro lens group in which a plurality of micro lenses for light distribution control are arranged separately or separately from the lens,
The optical lens has a convex surface formed facing the LED element, a concave surface formed so as to surround the LED element at a peripheral portion of the convex surface, and a reflection that totally reflects light from the LED element that has transmitted through the concave surface. A surface, and an exit surface that emits light from the convex surface and the reflective surface,
When the light distribution of the LED element is Lambert distribution, a lens shape for returning the light reaching the exit surface through the convex surface of the optical lens and the inflection point between the convex surface and the concave surface to parallel light on the exit surface A signal lamp provided on the emission surface. In a signal lamp comprising a light source composed of a plurality of LED elements arranged in a planar shape and an optical lens arranged corresponding to the front of each LED element,
Provided on the exit surface side of the optical lens is a micro lens group in which a plurality of micro lenses for light distribution control are arranged separately or separately from the lens,
The optical lens has a convex surface formed facing the LED element, a concave surface formed so as to surround the LED element at a peripheral portion of the convex surface, and a reflection that totally reflects light from the LED element that has transmitted through the concave surface. A surface, and an exit surface that emits light from the convex surface and the reflective surface,
A signal lamp characterized in that when the light distribution of the LED element is strong in the lateral direction, the reflection surface of the optical lens is formed so that the reflected light passes through a light distribution region where the emission surface is weak.

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