JPH02206000A - signal light - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a technology for preventing suspicious lighting in signal lights for transportation, railways, etc., and particularly relates to a Fresnel lens that replaces a parabolic reflector as a means for collimating a luminous flux. This invention relates to a novel signal light that uses a light source to obtain a predetermined scene as a signal light and prevents the occurrence of false lighting phenomena due to the incidence of external light.

[Conventional technology]

Conventionally, signal lights installed at road intersections, pedestrian crossings, etc., as shown in FIG.
The front surface thereof is covered with translucent front lenses 52 each having a filter function of a different color such as blue, orange, red, etc., so that a predetermined signal color is generated. However, since such a signal light is used with the main body 50 of the lamp supported above a pillar erected on the roadside, external light L1 such as sunlight and headlights of various vehicles is transmitted to the front lens of the signal light. 52
When entering the lamp body 50 through the
Since the light is reflected by the parabolic reflecting mirror 53 configured to have an angle of 0.0 and is again emitted to the outside of the lamp body 50, a so-called pseudo-lighting phenomenon occurs in which the light is visually recognized as if a signal light were turned on. Therefore, as a conventional means to eliminate this kind of false lighting phenomenon, a front lens 5 that covers the front opening of the lamp body 50 has been proposed.
A louver 55 consisting of a large number of fins 54 arranged horizontally in the direction of the surface of the front lens 52 is interposed between the light source 51 and the lighting light source 51, and the louver 55 blocks external light L1 from entering. A signal lamp is proposed in which the radiated light is emitted from the gap S between the fins 54 of the louver 55 to the outside of the lamp main body 50.

[Problem to be solved by the invention]

However, in this type of louver 55, as described above, a large number of fins 54 having a predetermined width are arranged in parallel in the surface direction of the front lens 52 at a constant interval S to block external light L from a predetermined direction.
1, which prevents the occurrence of pseudo-lighting phenomenon due to external light L1, and conversely also blocks the light emitted from the inside by the lighting light source 51, so that the light source 51 is blocked by the amount of light that is blocked. The problem is that the effective use of the emitted light is hindered, and it is not possible to obtain a predetermined amount of light as a signal light.

The present invention was devised in view of the above-mentioned problems, and it provides effective light shielding properties against external light such as sunlight irradiated from the outside, and does not reduce the transmittance of the light emitted from the internal lighting light source. The purpose is to provide signal lights.

[Means to solve the problem]

In order to achieve the above object, a signal light according to the present invention includes a light source supported substantially in the center of the lamp body, and a front lens made of a colored translucent material is attached in front of the light source. , the gist is to interpose a Fresnel lens as a beam collimating means between the light source and the front lens.

In addition, this Fresnel lens has a so-called meniscus shape that is concavely curved toward the back side of the front lens with a predetermined curvature centered on the optical axis of the light source, and if desired, the Fresnel lens is attached to the inner peripheral part of the lamp body. Alternatively, a reflecting mirror may be formed by continuously bending the reflected light beam with a curvature that refracts and deflects the reflected light beam into a parallel light beam through the Fresnel lens.

It is also possible to arrange a light shielding plate in a part of the lamp body that does not block the radiation path of the light source to the Fresnel lens, for example, to surround the outer periphery of the light source, so as to restrict the incidence of external light. be.

[Effect]

According to the above configuration, it is possible to eliminate the reflecting mirror inside the lamp body, which is a major cause of the occurrence of pseudo-lighting phenomenon caused by external light, and the emitted light from the light source can be controlled by the light beam collimating means. The light can be effectively emitted outside the lamp body through the Fresnel lens.

, Rikamo has a structure with an auxiliary and partial reflecting mirror that allows the light beam to be emitted from the step part of the Fresnel step, that is, the inner slope, so it is also possible to prevent a reduction in the amount of light used as a signal light. .

In addition, in a Fresnel lens that obtains a predetermined refractive index by carving a Fresnel step in a general Toko refractive system, in order to set a short focal length, the rise of the lens step must be made large. Since the lens becomes thicker by that much, the focal length cannot be set smaller than a predetermined value.

However, as shown in Figure 1, which shows a comparison between a meniscus-type Fresnel lens A (see Figure A) and a plano-convex Fresnel lens B (see Shikoku), the Fresnel lens A itself is concavely bent into a meniscus-type shape. In particular, the focal length f1 can be set small (fl<f2) at a light condensing rate (luminous flux collimation rate) equivalent to that of a normal plano-convex Fresnel lens B. As shown in FIG. 1, the solid angle using the light beam looking from the focal point F1 to the back surface of the Fresnel lens A, that is, the apex angle, is increased by the extent that the focal length f1 is smaller than the focal point f2 of the plano-convex Fresnel lens B. Similarly, θ1 is larger than the solid angle looking into the Fresnel lens B from the focal point F2 of the plano-convex Fresnel lens B, that is, the apex angle θ2 (θ1>θ2). Therefore, by placing the light source at the focal point Fl of the concave Fresnel lens, it becomes possible to make a relatively large amount of radiated light flux enter the Fresnel lens A compared to the plano-convex Fresnel lens B.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the signal light according to the present invention will be described below with reference to the drawings.

2 to 5 show a first embodiment of the signal light according to the present invention, in which a light source 2 for lighting is supported approximately at the center of the lamp body l, and the front opening is opened at a predetermined position. It is sealed with a front lens 3 made of a colored translucent material, and a Fresnel lens 4 is interposed between the front lens 3 and the light source 2 to refract and deflect the emitted light from the light source 2 into a parallel beam. It is. In the illustrated embodiment, the Fresnel lens 4 is curved so that the side cross-sectional shape is concave toward the front lens 3 in a meniscus shape. By using such a concave Fresnel lens 4, the above "effect" can be achieved.
As detailed in the column, the focal length f1 of the Fresnel lens 4
can be set small, and the depth of the lamp body 1 can be reduced.

The Fresnel lens 4 is provided with a large number of Fresnel steps 5 concentrically carved around the optical axis f of the light source 2 on its front surface, and an outer inclined surface 6 allows the radiation of the light source 2 to be reflected. It refracts and deflects the light into a parallel beam, and the distance fl is from the focal point Fl formed behind the Fresnel lens 4.
The inclination angle α is determined by the relative relationship between the critical angle T for the emitted light of the light source 2 and the curvature of the back side of the Fresnel lens 4, which is set at the outer circumferential extreme position of the Fresnel lens 4.
It was designed. In addition, the inclination angle β of the inner inclined surface 7 of the Fresnel step 5, which is a stepped portion, is such that the maximum value of the emission N (illumination area C) of the parallel light beam emitted from the Fresnel lens 4 is obtained It is designed to minimize the non-illuminated area formed by the area.

The inner surface of the lamp main body 1 is appropriately coated with black or other arbitrary anti-reflection processing to suppress reflection of external light.

Thus, the Fresnel lens 4 effectively refracts and deflects the emitted light from the light source 2 into a parallel beam of light and emits it out of the front lens 3, thereby functioning as a signal light. In addition, external light L1 such as sunlight that enters the lamp body 1 from the outside of the front lens 3 passes through the Fresnel lens 4 and irradiates the lamp body 1, but it is reflected inside the lamp body 1. Since it does not constitute a mirror, there is no reflection effect and no pseudo lighting phenomenon occurs.

FIG. 6 shows a second embodiment of the signal light according to the present invention. To explain the different parts from the first embodiment, reference numeral 11 indicates the inner periphery of the lamp body 1 to which the Fresnel lens 4 is attached. This is an auxiliary reflecting mirror formed in the area.

The reflecting mirror 11 emits the light emitted from the light source 2 as a parallel light beam in correspondence with the stepped portion of the Fresnel step 5 carved on the surface of the Fresnel lens 4, that is, the inner inclined surface 7, and the reflected light is On the other hand, the inclination angle β (see FIG. 4(b)) is designed so that the focal point F1 formed by the outer inclined surface 6 of the Fresnel step 5 is the same as the focal point F1.

Therefore, for example, in a signal lamp with a diameter of 250 mm,
When the concave Fresnel lens 4 is configured, the focal point F1 is connected approximately 80 mm from the rear of the Fresnel lens 4, and a conical light beam (arrow X) with an apex angle of approximately 100 degrees is transmitted from the light source 2 to the Fresnel lens 4. It is possible to irradiate the back side of the The reflector 11 exceeds this range, for example, 100
The radiated light in the range of 180 degrees to 180 degrees (arrow Y) is reflected once on the mirror surface, and is refracted and deflected into a parallel beam by the lens action of the inner inclined surface 7 of the Fresnel step 5, and then emitted to the outside of the front lens 3. Therefore, when the light emitted from the light source 2 is combined with the light flux of the portion indicated by the arrow X, approximately 50% or more of the light flux can be effectively used as signal light.

In this embodiment as well, the non-reflecting mirror portion (arrow Z
) is absorbed by the first inner surface of the lamp body and does not exit outside the lamp body 1 again. In addition, most of the external light L1 incident on the reflecting mirror 11 is
After being reflected once by 1, it is diffused into the lamp body 1,
Since it is absorbed into its inner surface, it does not cause a false lighting phenomenon.

FIG. 7 shows a third embodiment of the signal light according to the present invention, and parts different from the above-mentioned first and second embodiments will be explained.

This embodiment is intended to completely prevent external light from being reflected by the reflector when a reflector is configured on the inner surface of the lamp body 1 (above second embodiment), and the configuration of the reflector 11 is A light shielding plate 12 is disposed at the rear of the unit so as to surround the light source 2. The surface side of this light shielding plate 12 is appropriately subjected to anti-reflection processing to enhance the absorption effect of external light I, 1.

In this embodiment as well, as in the above-mentioned first and second embodiments, signal light can be effectively obtained by lighting the light source 2, and the signal light can be transmitted inside the lamp body 1 via the front lens 3 and the Fresnel lens 4. For external light L1 incident on the light shielding plate 1
2 to prevent the occurrence of false lighting phenomenon.

〔Effect of the invention〕

Since the signal light according to the present invention is constructed as described above, it has the effect of preventing false lighting due to external light such as sunlight, and is not only effective as a countermeasure against the setting sun for traffic signal lights and railway signal lights, but also has the effect of preventing lighting when the signal is turned on. This makes it possible to effectively utilize the emitted light from the light source, without reducing the illumination efficiency of the signal light.

In addition, compared to the conventional louver-type suspicious lighting prevention structure, the structure is simpler, there is no need to increase the depth of the lamp body, and maintenance and inspection are easy. It is something that you have.

[Brief explanation of the drawing]

1(a) and (b) are explanatory diagrams showing the optical principle of a Fresnel lens attached to a signal light according to the present invention, FIG. 2 is a side sectional view showing a first embodiment of the signal light according to the present invention, Figure 3 is also a front view of the Fresnel lens, Figure 4 (a)
and (b) are enlarged cross-sectional views of the main parts showing the structure of the Fresnel lens; FIG. 5 is a side cross-sectional view of the main parts showing the state of light emitted by the Fresnel lens; and FIG. Fig. 7 is a side sectional view of the main part showing the embodiment; Fig. 7 is a side sectional view of the main part showing the third embodiment; Fig. 8 is a side sectional view showing the structure of a conventional signal light. Main body...Front lens...Fresnel step...Inner inclined surface...Shading plate 2...Light source 4...Fresnel lens 6...Outer inclined surface 11...Reflector

Claims (7)

[Claims] (1) In a signal lamp that carries a light source approximately in the center of the lamp body and has a front lens made of a colored translucent material attached in front of the light source, a light beam collimating means is provided between the light source and the front lens. A signal light characterized by having a Fresnel lens inserted therein. (2) The signal lamp according to claim 1, wherein the Fresnel lens has a side cross-sectional shape that is concavely curved toward the back surface of the front lens with a predetermined curvature around the optical axis of the light source. (3) The signal lamp according to claim 1 or 2, wherein the Fresnel lens comprises a large number of Fresnel steps concentrically carved around the optical axis of the light source. (4) A reflecting mirror that is continuously curved with a curvature that refracts and deflects the reflected light beam into a parallel light beam through the Fresnel lens is formed on the inner peripheral part of the lamp body to which the Fresnel lens is attached. The signal lamp according to claim 1, 2 or 3, characterized in that: (5) The outer inclined surface of the Fresnel step engraved on the Fresnel lens forms an inclined angle that allows the emitted light from the light source to be refracted and deflected into a parallel light beam, and the inner inclined surface converts the light beam reflected by the reflecting mirror into a parallel light beam. 5. The signal light according to claim 2, wherein the signal light has an inclination angle that allows the signal light to be refracted and deflected. (6) The signal lamp according to claim 4 or 5, characterized in that a light shielding plate is disposed within the lamp body at a portion that does not block the radiation path of the light source to the Fresnel lens. (7) The signal lamp according to claim 6, characterized in that the light shielding plate is arranged so as to surround the outer periphery of the light source.