JP2006048165A - Signal light - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize uniform light emission with respect to a signal light with LED elements as light sources by increasing the light output of each LED element, and preventing the generation of the dark part of any gap between the LED elements even when the number of the LED elements is decreased by considering the combination of optical lens and minute lens. <P>SOLUTION: This signal light is provided with a light source constituted of a plurality of LED elements 3 arranged on a plane, and optical lens 41 correspondingly arranged in front of the respective LED elements, and a minute lens group 42 constituted by arranging a plurality of micro-fine lens for controlling light distribution is arranged integrally with or separately from the lens on the outgoing face sides of the optical lens 41. Also, the optical lens 41 are arranged so that any gap between the adjacent lens can be eliminated. <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. .

  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. It is an object of the present invention to provide a signal lamp that does not produce a dark part of the light and can realize uniform light emission.

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 group of minute lenses formed by arranging a plurality of minute lenses for light distribution control integrally or separately with the lens is provided.
In the above, it is preferable to set the apparent aperture of each lens of the micro lens group to be equal to or smaller than a value for allowing the light source to appear uniform.
In the above, it is preferable that the micro lens groups are arranged so that there is no flat portion on the lens exit surface.
In the above, it is preferable to arrange the optical lenses so that there is no gap between adjacent lenses.
In the above, the optical lens is a convex surface formed facing the LED element, a concave surface formed so as to surround the LED element at the peripheral portion of the convex surface, and the light from the LED element transmitted through the concave surface is totally reflected. It is preferable that a region far from the LED element is a pseudo cut surface parallel to the emission direction, and the pseudo cut surface is a connecting portion between adjacent optical lenses.
In the above, the optical lens preferably has a concave curved surface on the light exit surface.

According to the present invention, the light emitting area from each LED element is expanded by the optical lens and the light distribution is performed by the minute lens group, so that the light output of each LED element is increased and the number of LED elements is reduced. However, dark portions are less likely to be generated in the gaps between the optical lenses, and the uneven luminance distribution is reduced, and uniform light emission is possible. By making the apparent aperture of the micro lens group equal to or less than the value for making the light source appear uniform, the above effect becomes significant.
Further, by arranging the minute lens groups so that the flat surface portion is eliminated from the exit surface, the pseudo lighting is eliminated.
Further, by using the pseudo cut surface of the reflecting surface of the optical lens as the lens connecting portion, the gap between the optical lenses can be eliminated, and the effect of reducing the unevenness of the luminance distribution can be obtained more remarkably.
Further, by making the light exit surface of the optical lens a concave curved surface, the lens becomes thin, the lens moldability is improved, and the weight can be reduced.

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

  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 (hereinafter the same), and the micro lens group 42 provided on the exit surface of the optical lens 41 is also not shown. 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 42 (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.

  FIG. 7A shows the exit surface of the optical lens 41, and FIGS. 7B to 7D show arrangements of the microlenses 42 according to various embodiments. FIG. 7E shows a configuration to which the present invention is not applied. In FIG. 5E, since the flat portion 45 remains in the gap between the micro lenses 42, when external light hits the flat portion 45, it is specularly reflected, so that the viewpoint of the person in the direction of the reflected light is The visibility of light from the light source is greatly impaired. Therefore, in the present invention, in order to suppress such a situation and efficiently perform the necessary light distribution, as shown in FIG. 7A, the micro lenses 42 are arranged without gaps, and the plane portion is eliminated. . Therefore, the micro lens 42 is a regular n-gon (n = 3,4,6). The cases where n = 3, 4, and 6 are shown in FIGS.

By the way, the unit size of the microlens 42 for visually recognizing that the signal lamp emits light uniformly, that is, the apparent aperture, considers the visual acuity (about 0.7 to 1.0) of the driver who watches the signal lamp. It is desirable that it is 3 mm or less. The reason will be described with reference to FIGS. FIG. 5A shows the relationship between the microlens and the driver's visual acuity. When the diameter of the microlens is D (mm), the distance L (m), and the viewing angle is α (min), the visual acuity V is V = α ⁻¹ ,
tan {(α / 2) (1/60) (π / 180)} = (D / 2) / (L × 10 ³ )
It is expressed by the relational expression. Here, 1/60 is for converting minutes to degrees, and π / 180 is for radians. From the above relationship,
D = 2000 × L × tan (π / 21600 × V) (formula A)

FIG. 8B shows the relationship between the light distribution angle for viewing the signal lamp and the distance. Here, D is the apparent outer shape of the microlens in the signal lamp, D ′ is the outer shape of the microlens, and the downward viewing angle with respect to the horizontal of the signal lamp is 22.5 ° (lower limit of ITE: Institute of Transportation Engineers standard in the United States) Then,
D ′ = D / cos {22.5 × (π / 180)} (Formula B)
It is expressed. From these formulas A and B, when L is 10.5 m, the driver's visual acuity V is 0.7 to 1.0, and these values are substituted, D ′ = 3.3 to 4.7 mm. Therefore, in order to emit light with high uniformity, the outer shape of the micro lens is desirably 3 mm or less.

  FIG. 9A shows the shape and arrangement of the optical lenses 41 for light emission with high uniformity. The light transmitted and refracted by the concave surface C1 (corresponding to 41b in FIG. 4) of the optical lens 41 is totally reflected by the reflecting surface C2 (corresponding to 41c in FIG. 4), but actually the light that has passed through the upper end of the concave surface C1. It reaches only the position A where it is totally reflected, and the region B does not function as a lens surface. Therefore, a region B farther from the LED element 3 than the position A is set as a pseudo cut surface parallel to the emission direction E, and this pseudo cut surface is used as a connecting portion between adjacent optical lenses. By comprising in this way, the light from LED element 3 can be used effectively as much as possible, and the thing with the high uniformity of the light of the light emission surface is obtained.

  FIG. 9B is a view of the exit surface of one optical lens 41, and 46 is a circumference 46 at the position A, and light from the LED element 3 is within this circumference 46. Since it arrives, it emits light. In order to fill the inner surface of the circumference 46 with the regular n-gons 47 without gaps as much as possible and to improve the lens efficiency, it is preferable that n is large (n = ∞ becomes a circle). In this example, regular hexagons of n = 6 are closely arranged in order to fill the light exit surface with a light emitting portion with as little gap as possible and to increase the efficiency by effectively using a lens in practical use.

  FIG. 10A shows the optical lens 41 in this embodiment, and FIG. 10B shows an optical lens to which the present invention is not applied. As shown in FIG. 4A, in this embodiment, the lens is cut and closely connected so that the effective lens surface can be used effectively. As a result, the lens exit surface becomes a bright part (shaded part), and there is no dark part. On the other hand, as shown in FIG. 5B, when the individual lenses are regularly arranged so as to circumscribe without applying the present invention, the bright part and the dark part are visually recognized as they are. Will be bad.

  FIGS. 11A to 11D show examples of improving the moldability and reducing the weight of the optical lens. FIGS. 4A, 4B, and 4C show the exit surface 41d of the optical lens 41 having a concave shape. In any case, the lens shape is rotationally symmetric, and by forming a concave shape, the lens shape becomes thin, the moldability is good, the weight can be reduced, and the material cost can be reduced. On the other hand, in the conventional thick lens, when the number of light sources (LED elements) increases, the weight increases, and the shape reproducibility is not good due to the problem of resin sink marks. In FIG. 6A, the exit surface 41d is a concave curved surface, FIG. 5B is a concave shape with a plurality of planes, and FIG. Yes. In addition, in the same figure (c), the thinnest part shall be more than the limit required in order to maintain a lens shape. Further, in the configuration shown in FIGS. 5A, 5B, and 5C, the microlens is configured by a member separate from the optical lens 41. FIG. 4 (d) shows the exit surface 41d having a stepped concave shape. The step-shaped concave rising surface 41e in this configuration has a die draft θ. In the configuration shown in FIG. 4D, the micro lens can be provided integrally on the stepped plane of the emission surface 41 d of the optical lens 41.

  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.

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 of 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. (A) is a front view showing a minute lens on the exit surface of the optical lens, (b), (c) and (d) are arrangement diagrams according to various embodiments of the minute lens, and (e) does not apply the present invention. Sectional drawing of an optical lens and a micro lens. (A) is a figure for demonstrating the relationship between a micro lens and a driver | operator's visual acuity, (b) is a figure which shows the relationship between the light distribution angle and distance which visually recognize a signal lamp. (A) is a figure which shows the shape and arrangement | sequence of the optical lens for light emission with high uniformity, (b) is a figure which shows the shape seen from the output surface of one optical lens. (A) is a perspective view of the optical lens in this embodiment, (b) is a perspective view of the optical lens to which the present invention is not applied. (A) thru | or (d) is sectional drawing of the optical lens by various embodiment which aimed at the moldability improvement and weight reduction.

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 Outgoing surface 42 Micro lens group 44 Lens sheet B area | region (pseudo cut surface, connection part)

Claims (6)

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,
A signal lamp comprising a microlens group in which a plurality of microlenses for controlling light distribution are arranged separately or separately from the lens on the exit surface side of the optical lens.   2. The signal lamp according to claim 1, wherein an apparent aperture of each lens of the micro lens group is set to be equal to or smaller than a value for making the light source appear uniform.   The signal lamp according to claim 2, wherein the micro lens groups are arranged so that a flat surface portion is eliminated from the lens exit surface.   2. The signal lamp according to claim 1, wherein the optical lenses are arranged so that there is no gap between adjacent lenses.   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. An area far from the LED element of the reflective surface is a pseudo cut surface parallel to the emission direction, and the pseudo cut surface is a connecting portion between adjacent optical lenses. 4. Signal light according to 4.   6. The signal lamp according to claim 5, wherein the optical lens has a concave curved surface on a light exit surface of the lens.

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