JPH0325277Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention is a circle for traffic signal lights that can be attached to the front of the signal lamp of an existing traffic signal lamp for the purpose of blocking external light reflected by the reflector of the signal lamp. This invention relates to a lamp hood with a polarizing filter.

Conventional technology When external light, such as sunlight or automobile headlights, enters the lamp unit through the lens of a signal light,
The light is reflected by the reflector inside the lamp and emitted to the outside through the lens again, creating a so-called phantom effect that makes it appear as if the signal light is on even though it is not. It is known to cause Particularly during the day, sunlight makes it difficult for motorists, pedestrians, etc. to identify traffic lights (pseudo-appearance).
This phenomenon is a cause of traffic control confusion and a factor in the occurrence of traffic accidents. Therefore, various proposals have been made and put into practice.

For example, a lamp hood using louvers as shown in FIGS. 4 and 5 has been known as a means for preventing such pseudo-displays. That is, as shown in the figure, this lamp hood has a louver 43 made of a large number of horizontal black-painted light-shielding plates attached to the hood body 42 attached to the front of a colored lens 41. On the other hand, external light such as sunlight or the headlights of an automobile that enters obliquely is blocked or attenuated by a horizontal louver 43 painted in black. On the other hand, the regular light emitted from the light bulb 45 for signal display passes through the gap between the louvers 43 and is emitted directly to the outside, and the light emitted backward is reflected by the reflecting mirror 44 on the optical axis of the paraboloid. The light rays become parallel to , and are emitted to the outside without being blocked by the louvers 43.

Problems to be Solved by the Invention The causes of the above-mentioned similar phenomena and the difficulty in identifying whether a traffic signal light is on or off are as follows.

As shown in Fig. 5 above, sunlight coming from the front of the traffic signal light (left side in the figure) has a colored lens 41.
, is reflected by the reflecting mirror 44, passes through the colored lens 41 again, exits the traffic light, and is radiated to the left in the figure.

In this case, neither the driver of the vehicle nor the pedestrian can distinguish between the emitted light and the light emitted from the light bulb 45.

Note that the light emitted from the light bulb 45 includes light that passes directly from the light bulb 45 through the colored lens 41 when lit, and light that is reflected by the reflecting mirror 44 and then passes through the colored lens 41.
This includes both the light passing through 1 and the light passing through 1. Therefore, drivers and pedestrians cannot tell which traffic signal lights are on or off.

The present invention aims to eliminate the above-mentioned causes and provide a safe and comfortable transportation system for both drivers and pedestrians.

In addition, conventional lamp hoods using the louvers described above have the problem that the visual field of the signal is narrowed because the louvers 43, which require depth, are incorporated, resulting in poor visibility from a position away from the extension of the optical axis. Ta. In addition, there are various problems in actual use, such as foreign matter (for example, dead leaves, snow, etc.) easily becoming clogged between the louvers 43, and birds and the like building nests between the louvers.

This invention was devised based on the above circumstances,
The object of the present invention is to provide a lamp hood that does not have the above-mentioned problems and can be attached to a conventional traffic signal light.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention provides a lamp hood that can be attached to the front of each signal lamp of a traffic signal lamp. The present invention provides a lamp hood for a traffic signal light, in which a circular polarizing filter made of a linear polarizing film and a quarter wavelength film is attached to a position covering the light emitting surface of the front surface of the signal lamp.

Function When a lamp hood with the above configuration is attached to the front of each signal lamp of a traffic signal light, as shown in Figure 3, the incident external light becomes circularly polarized light through a circularly polarizing filter and enters the lamp unit, but there is no reflection. By being reflected by the mirror, the direction of rotation of the circularly polarized light is reversed, and as a result, it cannot pass through the circularly polarizing filter again, thereby preventing false displays caused by extraneous light. On the other hand, the light from the light bulb, which is the light source, is polarized by the circular polarizing filter, so the amount of light is slightly reduced, but it passes through the circular polarizing filter and is radiated to the outside, achieving a normal signal display.

Embodiment Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. , are arranged so as to surround the outer periphery of the colored lens 2, and are detachably attached to the lamp outer box 6 using mounting fittings 3, 4 and screws 5. The hood main body 1 generally has a shape of a cylindrical body with a portion of the lower part cut away as shown in the illustrated example, but the shape is not limited to this. Moreover, it may be fixedly connected to the lamp outer box 6 instead of being detachable.

Inside the hood body 1, a circularly polarizing filter 7 is attached to a position covering the light emitting surface of the signal lamp 17 so as to be openable and closable by a hinge 8. For example, as shown in FIG. 2, this circularly polarizing filter 7 is made of a polymer film with a thickness of 1/4 wavelength of visible light between two transparent glass plates 9, 9. A film 10, a linearly polarized film 11 made of dyed polymer film stretched extremely thinly, and an ultraviolet cut film 12 for protecting these films 10 and 11 are sandwiched, and the edges are coated with synthetic resin or the like to prevent moisture. After being sealed, they are assembled together using a frame 13. Note that the 1/4 wavelength film 10 and the linearly polarized film 11 are arranged with their main axes tilted by 45 degrees.

The lamp hood for a traffic signal lamp of the present invention, which has the circularly polarizing filter 7 inside the hood body 1 as described above, blocks external light and prevents false indications in the following manner. That is, FIG. 3 is an explanatory diagram of the operation of the circularly polarizing filter 7, and if the operation of the circularly polarizing filter 7 is explained using this figure, generally the external light L
can be thought of as a collection of light rays vibrating in all directions. When this external light L passes through the linearly polarized film 11 of the circularly polarized filter 7, only linearly polarized light _L1 vibrates in the vertical direction (in the illustrated example).
This linearly polarized light L ₁ is placed on a 1/4 wavelength film 10 with its main axis tilted at 45 degrees with respect to the linearly polarized film 11.
As shown in the figure, the circularly polarized light L ₂ turns to the right (in the illustrated example), reaches the reflector 14 of the signal light, and is reflected outward again by the reflector 14 .

By the way, it is well known that when circularly polarized light is reflected by a glass surface, a metal mirror surface, etc., the direction of rotation of the circularly polarized light is reversed. Therefore, the right-handed circularly polarized light L ₂ is reflected by the reflecting mirror 14 to become the left-handed circularly polarized light L ₃ and enters the quarter-wavelength film 10 again.

The circularly polarized light L 3 which is the light reflected by the reflecting mirror 14 that is incident on the 1/4 wavelength film ₁₀ is reflected from the 1/4 wavelength film 1
By passing through 0, the reflected light becomes linearly polarized light _L4 again, but this reflected light, linearly polarized light _L4 , has a vibration plane that is higher than that of the linearly polarized light _L1 caused by the first external light.
It becomes linearly polarized light that is rotated 90 degrees and vibrates in the horizontal direction. Therefore, this horizontally oscillating linearly polarized light
L ₄ cannot pass through the linearly polarizing film 11. As a result, the external light L that has entered the signal lamp 17 is blocked by the circular polarization filter 7,
This effectively prevents pseudo-displays caused by extraneous light.

On the other hand, the light emitted from the light bulb 15 in the signal lamp 17 is not subjected to the above-mentioned effect, so it is filtered through the circularly polarizing filter 7.
Although the amount of light is slightly reduced due to polarization when passing through, it is radiated to the outside as it is, and a normal signal can be displayed.

In the case of the lamp hood shown in FIG. 1, remove the set screw 16 and attach the circular polarizing filter 7 to the lower hinge
By opening downward using the lamp as a fulcrum, it can be easily attached to the lamp outer box 6 using the mounting brackets 3, 4 and screws 5. Therefore, it can be easily replaced with a conventional lamp hood. Furthermore, in order to reduce the influence of reflection on its surface, it is preferable that the circularly polarizing filter 7 is not perpendicular to the optical axis of the reflecting mirror 14 but is inclined. It is even better to apply a well-known anti-reflection coating to the filter surface.

In the above embodiment, a case has been described in which the lamp hood for a traffic signal light of the present invention is configured to be detachable from the lamp outer box 6 of the traffic signal lamp, but it may also be integrated and connected to the lamp outer box 6 from the beginning. Of course it's a good thing. Furthermore, although the circularly polarizing filter 7 is configured to be freely openable and closable with respect to the hood body 1 by means of a hinge 8,
Of course, it may be fixedly arranged so that it cannot be opened or closed.

Effects of the invention The lamp hood for traffic signal lights of the present invention has the structure and function as explained above, and by installing a circularly polarizing filter on the hood body at a position covering the light emitting surface of the signal lamp, It is possible to block the reflected light of external light that enters the signal lamp without using a large louver or the like which takes up a large volume, and it has the excellent effect of preventing false displays caused by external light.

Furthermore, the lamp hood for traffic signal lights of the present invention,
A circular polarizing filter is incorporated in the lamp hood at a position that covers the light emitting surface of the signal lamp, which serves as a means to prevent false indications, so even if you are using a conventional traffic signal lamp, you can simply replace the lamp hood with a lamp hood equipped with a circular polarizing filter. It has the excellent effect of being easy to replace and install.

In addition, the lamp hood for traffic signal lights of the present invention uses the polarization effect of the circular polarizing filter to block the light reflected from each signal lamp due to external light, so it can be used regardless of the incident angle of the external light that enters the signal lamp. It has the effect of blocking reflected light, and can reliably block reflected light from external light that enters from the horizontal direction, which was difficult with conventional louvers, and does not require bulky light blocking means such as louvers. , the visibility of the signal can be improved without narrowing the field of view of the signal light, the lamp hood of a conventional traffic signal light can be extremely easily replaced with a lamp hood with a circular polarizing filter, and the light bulb inside the signal light can be easily replaced. This has an excellent effect in that the light emitted from the lamp is radiated to the outside as it is, with only some dimming.

[Brief explanation of drawings]

Fig. 1 is a sectional view of an embodiment of a lamp hood for a traffic signal light installed in place of a conventional lamp hood for a traffic signal lamp, Fig. 2 is a partially enlarged sectional view showing an example of the structure of a circular polarizing filter, and Fig. 3 is an explanatory diagram of the light shielding effect of the circularly polarizing filter in the present invention, FIG. 4 is a schematic front view of a signal light using a conventional louver, and FIG.
The figure is a sectional view of the same upper side. 1...Hood body, 2...Colored lens, 6...Outer box of lamp, 7...Circular polarizing filter, 9...Transparent glass plate, 10...1/4 wavelength film, 11...Linear polarizing film, 12...Ultraviolet cut film,
14...Reflector, 15...Light bulb, 17...Signal lamp, L...External light, _L4 ...Linearly polarized light that is reflected light.

Claims (1)

[Claims for Utility Model Registration] A lamp hood for a traffic signal light having a circularly polarizing filter 7, wherein the circularly polarizing filter 7 is a linearly polarizing film 11.
and a 1/4 wavelength film 10, wherein when the hood is attached to the signal lamp 17, the circularly polarizing filter 7 covers the light emitting surface of the signal lamp 17.