JPH0772419A - Illuminating optical system - Google Patents

Abstract

PURPOSE:To utilize a radiating light beam toward the peripheral direction for illumination and to improve the illuminating efficiency by providing a reflection means for introducing a light beam radiated toward the peripheral direction of a light source among the light rays from the light source. CONSTITUTION:This illuminating optical system is provided with a collimator lens 1, a filter 2, a light source 5 located on the rear focusing position of the collimator fens 1 and a reflection means for introducing a light beam (b) radiated toward the peripheral direction of the light source 5 to the object side to be irradiated. Namely, the light beam (b) radiated toward the peripheral direction of the light source 5 among the radiated beams from the light source 5 is reflected by the reflection surface of a parabolic reflection mirror 3, becomes a parallel beam and travels backward. The light beam is made incident on the conical reflection surface of a bent reflector 4 and reflected. It is further reflected by the bent part of the conical reflection surface and sent to the front of an illuminating optical system in the state the traveling direction is reversed by 180 deg. as a result. This reflected light beam is transmitted through a transparent window and the object to be irradiated is irradiated with the beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical system used for lighting equipment such as a flashlight, a headlight or a signal light.

[0002]

2. Description of the Related Art Conventionally, there has been an apparatus shown in FIG. 3 as an illumination optical system used in various luminaires. In this device, the light flux a traveling forward (on the side of the irradiated object) of the light rays emitted from the light source 15 is collimated by the collimator lens 11.
Is converted into a parallel light flux, and is radiated toward an irradiation target such as an observer or a target.

Of the light rays emitted from the light source 15, the light flux c traveling rearward (back side) is reflected by the reflecting mirror 16 disposed on the back surface of the light source 15, returns to the light source 15 side again, and the light flux a. Similarly to the above, the parallel light flux passes through the collimator lens 11 and travels toward the irradiation target.

[0004]

However, in the prior art as described above, only the luminous flux a emitted forward from the light source and the luminous flux c emitted rearward are utilized, and the circumferential direction of the light source is reduced. The luminous flux b radiated to is not used and wasted. As can be seen from the light distribution characteristics of the light source shown in FIG. 2, the proportion of the light beam c emitted from the light source is smaller than that of the unused light beam b.

Further, the luminous flux c is made available by the reflecting mirror 16, but the light reflected by the reflecting mirror 16 is once emitted from the light source 1.
Since the light enters the collimator lens after passing through the filament No. 5, the filament itself is eclipsed, which is not very efficient. As described above, the conventional lighting device has a poor light utilization rate.

It is also conceivable to increase the numerical aperture of the collimator lens 11 to increase the relative proportion of the light beam a, but in this case, it is not only difficult to manufacture a collimator lens having a large numerical aperture, but also The maximum angle of capturing the light flux a is about 120 ° to 150 °, and the irradiation efficiency cannot be greatly improved.

An object of the present invention is to solve the above-mentioned problems and to obtain an illumination optical system in which the light emitted from a light source can be used with high efficiency than ever before.

[0008]

To achieve the above object, in an illumination optical system according to a first aspect of the present invention, a light source and a collimator for emitting a light beam from the light source to a side of an object to be illuminated as a parallel light flux. In the illumination optical system including a lens, a reflection unit is provided for guiding the light emitted in the circumferential direction of the light source among the light rays to the side of the object to be illuminated.

According to a second aspect of the present invention, in the illumination optical system according to the first aspect, the reflecting means is disposed between the light source and the collimating lens and has a predetermined diameter in a central portion. And a bending mirror having a conical reflecting surface disposed on the back surface of the light source, and the collimator lens is provided with the reflected light from the bending mirror at its circumferential position. It has a window portion that transmits to the object side.

[0010]

In the present invention, when the light beam from the light source is applied to the illuminated object side as a parallel light flux through the collimating lens, the light emitted in the circumferential direction of the light source is also directed to the illuminated object side by the reflecting means. It is a guide. Thereby, the light emitted in the circumferential direction of the light source can also be used for illumination.

As is apparent from the light distribution characteristics of the light source shown in FIG. 2, the ratio of the light radiated in the circumferential direction of the light source, which has not been conventionally used, to the entire light beam was large. Therefore, according to the present invention, of the light beams emitted from the light source, the light beam emitted in the circumferential direction of the light source can be used for illumination in addition to the light beam emitted to the front, which has been mainly used in the past, so that the illumination efficiency is improved. It becomes possible.

Further, according to the present invention, a concave mirror having a hole having a predetermined diameter at the center is disposed between the light source and the collimating lens as a reflecting means for guiding the light emitted in the circumferential direction of the light source to the illuminated side. At the same time, a bending reflecting mirror having a conical reflecting surface is arranged on the back surface of the light source, and a window portion is provided at the circumferential position of the collimating lens to transmit the reflected light from the bending reflecting mirror to the illuminated object side.

In the above structure, of the light emitted from the light source, the light flux emitted forward passes through the hole provided in the central portion of the concave mirror and enters the collimator lens.
Similar to the conventional illumination optical system, it is emitted as a parallel light beam toward the object to be illuminated.

On the other hand, the luminous flux emitted in the circumferential direction of the light source is reflected by the concave mirror, is incident on and reflected by the conical reflecting surface of the bending reflecting mirror, and is further incident on and reflected by the bent portion to become a parallel luminous flux, which is a collimating lens. Reach the lap position.
A window portion is provided at the peripheral position of the collimator lens, and the reflected light from the bent portion is directly transmitted through the window portion and emitted to the illuminated object side.

As described above, according to the illumination optical system of the present invention, a simple structure is provided that includes the reflecting means including the concave mirror and the bent reflecting mirror having the conical reflecting surface. The luminous flux emitted in the circumferential direction of the light source can be used as the illumination light, and higher illumination efficiency than ever can be realized.

[0016]

EXAMPLE An example of the present invention will be described below. In the illumination optical system according to the present embodiment, the collimator lens 1, the filter 2, the light source 5 installed at the rear focal point of the collimator lens 1, and the light flux b radiated in the circumferential direction of the light source 5 are irradiated onto an object (not shown). ) Side is equipped with a reflection means for guiding. The collimator lens 1 is integrally provided with a flat window portion for passing light through the lens periphery.

The reflection means is arranged between the filter 2 and the light source 5, and is a parabolic reflector 3 having a hole of a predetermined diameter in the center thereof.
And a folding reflecting mirror 4 arranged on the back side of the light source 5 and having a conical reflecting surface in the center. The parabolic reflector 3 is set so that the light source 5 is located at its focal position.

First, of the light emitted from the light source 5, the light flux a emitted forward (on the side of the object to be illuminated) passes through the hole of the parabolic reflector 3 and passes through the filter 2 to form a collimator lens. The 1st lens unit forms a parallel light beam and irradiates the object to be illuminated. Here, the hole diameter of the parabolic mirror 3 may be set according to the angle at which the light beam a can be taken in by the lens portion of the collimator lens 1.

At the same time, of the light emitted from the light source 5, the light beam b emitted in the circumferential direction of the light source 5 is reflected by the reflecting surface of the parabolic reflector 3 and becomes a parallel light beam and travels backward. This light beam is incident on the conical reflecting surface of the bending reflecting mirror 4, is reflected, and is further reflected by the bent portion of the circumference of the conical reflecting surface. As a result, the direction of travel is reversed by 180 ° and is directed forward of the illumination optical system. Go to The reflected light flux is transmitted through the window portion of the collimator lens 1 and is irradiated onto the object to be illuminated.

The reflecting mirror 6 arranged at the rear portion of the light source 5 reflects the light beam c emitted backward from the light emitted from the light source 5 and directs it forward. However, in the case of a light source having a light distribution characteristic as shown in FIG. 2, the proportion of the luminous flux c radiated rearward in the whole is small, and further, after being reflected by the reflecting mirror 6, the filament itself of the light source causes eclipse. Therefore, the effect of improving the light use efficiency is not so great. Therefore, the installation of the reflecting mirror 6 may be omitted in order to simplify the mechanism.

As described above, according to the illumination optical system of the present embodiment, it is possible to use the luminous flux b emitted in the circumferential direction of the light source 5, which has not been used conventionally.

In the above embodiment, the collimator lens 1 is an integral type of the lens part and the transparent window part.
The present invention is not limited to this, and the lens portion and the window portion may be configured by separate members. Further, it is possible to adopt a configuration in which the window portion is not provided.

Further, in the above embodiment, the filter 2 is provided between the collimator lens 1 and the light source 5, but this can provide a desired color when an illumination light of a predetermined color such as a signal lamp is required. A wavelength selection filter or the like that transmits only the wavelength light to be presented is used. It goes without saying that a structure excluding the filter may be used when simply illuminating the target object.

[0024]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, of the light emitted from the light source, in addition to the forward luminous flux, the circumferential luminous flux which has not been conventionally used can be utilized for illumination. We were able to improve efficiency.

Therefore, according to the illumination optical system of the present invention which can efficiently capture the light beam from the light source and irradiate it toward the target, the visibility can be improved when it is used for a signal light, and a pocket is provided. When used as a headlight such as an electric light, there is an effect that the target can be illuminated brighter.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an illumination optical system according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a light distribution characteristic of a light source used in an illumination optical system.

FIG. 3 is a schematic configuration diagram of a conventional illumination optical system.

[Explanation of symbols]

 1, 11: Collimating lens 2, 12: Filter 3: Parabolic reflecting mirror 4: Bending reflecting mirror 5, 15: Light source 6, 16: Reflecting mirror

Claims (2)

[Claims] 1. An illumination optical system comprising: a light source; and a collimator lens that emits a light beam from the light source as a parallel light flux toward an object to be illuminated. Among the light beams, the light emitted in the circumferential direction of the light source is An illumination optical system comprising a reflection means for guiding the object to be illuminated. 2. The bending means, wherein the reflecting means is provided with a concave mirror arranged between the light source and the collimating lens and having a hole of a predetermined diameter in the center thereof, and a conical reflecting surface arranged on the back surface of the light source. The illumination optical system according to claim 1, wherein the illumination optical system comprises a reflecting mirror, and the collimator lens has a window portion at a peripheral position thereof for transmitting reflected light from the bending reflecting mirror to the side of the object to be illuminated.