JPH095665A - Lighting equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] When observing an object by the reflected light from the object when the object is illuminated with the illumination light from the illumination light source, the object may be in a fog or the like that cannot be conventionally observed. Even if it is possible to observe the object. In an illuminating device configured to observe an object rest by reflected light from an object when the object is illuminated with the illuminating light emitted from the illuminating light source, the opening angle of the illuminating light in the illuminating light source is The illumination light source is arranged in such a relationship that it becomes smaller than the angle formed by the optical axis and the optical axis of the reflected light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device for observing an object by the reflected light from the object when the object is illuminated with the illuminating light emitted from an illuminating light source.

[0002]

2. Description of the Related Art Conventionally, as a lighting device of this type, FIG.
As shown in FIG. 3, the front area is illuminated by the illumination light LL having a relatively wide beam divergence angle from the illuminator 1, and the reflected light RL from the object 3 existing in the illumination area is reflected by the eyes 2 of the observer.
By entering, the object 3 can be observed.

In such a conventional illuminating device, when the aerosol Z such as fog, smoke, and dust exists in the object observation space, the illumination light LL from the illuminator 1 is scattered by the aerosol Z, and the scattered light. The light N toward the eyes 2 of the observer becomes noise. In addition, aerosol Z
A part of the illumination light LL that has passed through the object illuminates the object 3, but the reflected light RL is further scattered and attenuated by the aerosol Z, and only a small amount of the reflected light RL reaches the observer's eye 2. It's gone.

Therefore, as the amount of aerosol Z in the object observation space increases, noise increases,
The arrival amount of the reflected light RL from the object 3 decreases, and it becomes difficult to observe the object 3 even if the light intensity of the illumination light LL is increased.

[0005]

The problem to be solved by the present invention is that, in the conventional lighting device, when aerosols such as fog, smoke, and dust exist in the object observation space, the illumination light emitted to the object and the light from the object are emitted. The reflected light is scattered and it becomes impossible to observe the object.

[0006]

SUMMARY OF THE INVENTION The present invention is an illumination device for observing an object by reflected light from the object when the object is illuminated with the illumination light from the illumination light source. Even if aerosols such as fog, smoke, and dust exist in the object observation space, by devising the relative relationship between the opening angle of the illumination light and the arrangement of the illumination light source for the observer SN
The object can be observed by the reflected light from the object having a high ratio.

Therefore, according to the present invention, the illumination light source is arranged in such a relationship that the opening angle of the illumination light in the illumination light source becomes smaller than the angle formed by the optical axis of the illumination light and the optical axis of the reflected light. I am trying to do it.

[0008]

FIG. 2 is a simulation for measuring the SN ratio of the reflected light RL when the opening angle θ of the illumination light is variously changed while varying the installation distance D between the illuminator 1 and the optical sensor 4. A model is shown, and in the fog where the transmittance of the illumination light (visible light) LL is reduced to about 5% at 50 m, the reflected light RL from the object 3 having a reflectance of 1 placed at 50 m is measured by the optical sensor 4. It is designed to receive light.

FIG. 3 shows the characteristics of the simulation result at that time. In the characteristic diagram, the horizontal axis represents the installation distance D between the illuminator 1 and the optical sensor 4, and the vertical axis represents the SN ratio. Further, as the opening angle θ of the illumination light LL,
0.5 m radian, 1 m radian, 2 m radian, 0.
The parameters of 5 °, 5 °, 10 ° and 20 ° are taken.

Looking at this simulation result, as the opening angle θ of the illumination light LL by the illuminator 1 becomes smaller, S
It can be seen that the N ratio is improved. Also, it can be seen that the SN ratio improves as the installation distance D between the illuminator 1 and the optical sensor 4 increases.

This means that when the opening angle θ of the illumination light LL is reduced and the installation distance D between the illuminator 1 and the optical sensor 4 is increased, the illumination area A and the reflected light R of the illumination light LL are increased.
The size of the overlapping region C with the reflection region B of L becomes small,
It is considered that this is because the amount of the noise light N directed to the optical sensor 4 when the illumination light LL is scattered by the fog is suppressed.

In consideration of the results of the above examination, the present invention illuminates the space in front by the illumination light LL from the illuminator 1 as shown in FIG.
In the illuminating device in which the reflected light RL from the illuminator 1 enters the observer's eye 2 so that the object 3 can be observed, the opening angle θ of the illuminating light in the illuminator 1 is the illuminating light LL. The illuminator 1 is arranged so as to have a relationship (θ <α) that is smaller than the angle α formed by the optical axis of the above and the optical axis of the reflected light RL.

Here, a case where an illuminator 1 is arranged above a vehicle body (not shown) of an automobile and a driver observes an obstacle 3 in front of the vehicle below the illuminator 1 will be described. I am assuming.

In this case, the illuminator 1 has an aperture that allows the illumination light LL emitted from the front of the vehicle to have a rectangular shape that spreads in the left-right direction.
Then, here, attention is paid to the opening angle θ in the up-down direction in the rectangular illumination light LL having a spread in the left-right direction. Instead of using the rectangular aperture, the circular or rectangular illumination light LL emitted from the illuminator 1 is scanned in the left-right direction to obtain a light distribution pattern having a rectangular cross section. It goes without saying that it is good.

However, by setting the illuminator 1 at a predetermined position with respect to the eyes 2 of the observer and setting the opening angle θ of the illumination light to a predetermined value so that the relationship of θ <α is satisfied, The size of the overlapping area C of the illumination area A of the illumination light LL and the reflection area B of the reflected light RL is minimized in an in-vehicle device with a limited installation interval between the illuminator 1 and the observer's eye 2. You will be able to set the limit.

Therefore, even if aerosol such as fog, smoke, and dust exists in the object observation space, the amount of noise light N directed to the light receiving portion of the observer's eye 2 when the illumination light LL is scattered by the aerosol is large. The object 3 can be observed with the reflected light RL that is suppressed to the minimum and has a high SN ratio.

In this case, based on the above simulation results, the illumination device of the present invention can be used as, for example, illumination light LL.
The opening angle θ is set to 1 m radian, the installation distance D between the illuminator 1 and the observer's eye 2 is set to 50 cm, and the transmittance of the illumination light LL is reduced to about 5% at 50 m. When the reflected light RL from the object 3 placed 50 m ahead is obtained in the fog, the opening angle θ of the illumination light LL is 5 ° to 2
The SN ratio is improved by 2 to 3 digits as compared with the conventional one when the other conditions are set to be the same at 0 °.

Therefore, a large amount of aerosol such as fog, smoke, and dust exists in the object observation space, and the noise light quantity becomes larger than the reflected light quantity from the object 3 depending on the conventional setting shown in FIG. According to the present invention, the object 3 can be surely observed even when the object 3 cannot be observed.

Further, according to the present invention, the illumination angle LL of the illumination light LL from the illuminator 1 becomes a narrow light distribution pattern, and the light intensity per unit area can be easily increased.

As the illuminator 1 used in the present invention, it is possible to obtain illumination light having a predetermined opening angle θ simply by changing the reflection plate and the lens in the conventional illuminator. Further, as the light source of the illuminator 1, it is possible to use a laser or an LED other than an ordinary lamp. When a laser or an LED is used, the spectrum width of the light source is narrow, so by providing a bandpass filter on the optical sensor 2 side, it is possible to further increase the SN ratio for ambient light.

[0021]

As described above, in the illumination device according to the present invention, when the object is observed by the reflected light from the object when the object is illuminated with the illumination light from the illumination light source, the opening angle of the illumination light is the illumination light. Even if aerosols such as fog, smoke, and dust exist in the object observation space, the illuminators are arranged so that they are smaller than the angle between the optical axis of It becomes possible to observe an object with reflected light from an object having a high SN ratio with respect to scattered noise, and it is possible to observe an object even in a state where the object cannot be conventionally observed. It has the advantage that it can.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a lighting device according to the present invention.

FIG. 2 is a schematic configuration diagram of a simulation model for measuring an SN ratio of reflected light from an object in the lighting device.

FIG. 3 shows the opening angle of the illumination light as a parameter, the horizontal axis represents the installation distance between the illuminator and the optical sensor, and the vertical axis represents SN.
It is a characteristic view of the simulation result which took the ratio.

FIG. 4 is a schematic configuration diagram showing a conventional lighting device.

[Explanation of symbols]

 1 illuminator 2 observer's eye 3 object 4 optical sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaaki Abe 1-4-1 Chuo, Wako-shi, Saitama, Ltd.

Claims (1)

[Claims] 1. An illumination device configured to observe an object by reflected light from an object when the object is illuminated with the illumination light emitted from the illumination light source, wherein the opening angle of the illumination light in the illumination light source is the illumination light. An illuminating device in which an illuminating light source is arranged so as to be smaller than an angle formed between the optical axis of the optical axis and the optical axis of the reflected light.