JPH095663A - Stray light removal device for coaxial irradiation imaging device - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to obtain a stray light removing device for a coaxial irradiation imaging device which is small in size and can suppress deterioration of a camera image due to stray light. [Structure] A camera 1 is arranged in a housing 5 so that its optical axis passes through an opening 5a. Then, the half mirror 2 is arranged on the optical axis of the camera 1, the light emitting diode 3 irradiates the emitted light to the half mirror 2, and the reflected light is coaxial with the optical axis of the camera 1 and is exposed from the opening 5a to the outside. It is arranged to be emitted to. Further, of the light emitted from the light emitting diode 3, an optical attenuation filter 6 is arranged on the optical axis of the transmitted light that passes through the half mirror 2 and is inclined with respect to the optical axis. Further, the non-reflecting body 4 is arranged so that the light reflected by the light attenuation filter 6 of the transmitted light is incident.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stray light eliminating device in a coaxial irradiation image pickup device mounted on, for example, an automobile to detect a retina reflection of a driver.

[0002]

2. Description of the Related Art FIG. 7 is a schematic structural view showing a stray light removing device of a conventional coaxial irradiation image pickup device. In the drawing, 1 is a camera, 2 is a half mirror installed on the optical axis of the camera 1,
Reference numeral 3 denotes a light emitting diode that emits near-infrared light as a light emitting means. With respect to the half mirror 2 and the light emitting diode 3, the light emitted from the light emitting diode 3 is applied to the half mirror 2 and reflected by the half mirror 2. The reflected light is arranged so as to be coaxial with the optical axis of the camera 1. Reference numeral 4 is a non-reflective body formed by sticking a black gauze on the inner wall surface of the box body. This non-reflective body 4 absorbs the transmitted light passing through the half mirror 2 out of the light emitted from the light emitting diode 3. .
Reference numeral 5 is a housing of the coaxial irradiation image pickup device provided with an opening 5a through which the light emitted from the light emitting diode 3 is reflected by the half mirror 2. In addition, a to e in the figure
Represents the optical path of the emitted light emitted from the light emitting diode 3.

Next, the operation of the stray light removing device of the conventional coaxial irradiation image pickup device will be described. Light emitting diode 3
The emitted light emitted from travels along the optical path a, reaches the half mirror 3, and is split into reflected light and transmitted light. Then, the reflected light thus split is transmitted through the optical path b coaxial with the optical axis of the camera 1.
And is emitted to the outside of the housing 5 through the opening 5a. When the light emitted from the housing 5 is applied to the pupil coaxially with the driver's pupil, the light is reflected by the retina, travels in the opposite direction along the optical path b, passes through the half mirror 2, and passes through the camera. 1 is received. On the other hand, the transmitted light split by the half mirror 2 travels along the optical path c, reaches the non-reflecting body 4, is absorbed, and is prevented from being received by the camera 1 as stray light. Therefore, if the driver is dozing, the retina reflected light cannot be received by the camera 1, and the driver's dozing is detected. Then, for example, by sounding a buzzer or the like, the driver can be alerted and an accident due to a dozing driving can be prevented.

[0004]

As described above, the stray light removing device of the conventional coaxial irradiation image pickup device has the non-reflecting body 4 arranged to absorb the transmitted light split by the half mirror 2. However, since there is no object that completely absorbs light, part of the transmitted light that has entered the non-reflecting body 4 becomes scattered light. Then, a part of the scattered light travels on the optical path d to reach the half mirror 2, is reflected by the half mirror 2 and travels on the optical path e to enter the camera 1 as stray light, thereby deteriorating the image of the camera 1. There was a problem of being lost. Also,
As a countermeasure against this, the transmitted light divided by the half mirror 2 is diffused to reduce the amount of light per unit area incident on the non-reflector 4 to suppress the generation of scattered light on the non-reflector 4, or In order to diffuse the scattered light from the body 4 and reduce the scattered light incident on the half mirror 2, it is conceivable to increase the distance between the half mirror 2 and the non-reflecting body 4, but in this case, the non-reflecting body is used. 4 has a problem in that the size of the device is increased and the device is increased in size.

The present invention has been made to solve the above problems, and provides a stray light removing device for a coaxial irradiation image pickup device which is small in size and can suppress deterioration of a camera image due to stray light. With the goal.

[0006]

According to a first aspect of the present invention, there is provided a stray light removing device for a coaxial irradiation image pickup device, a housing having an opening, and a camera arranged in the housing so that an optical axis passes through the opening. , A half mirror arranged in the housing so as to be located on the optical axis of the camera, and the emitted light is applied to the half mirror, and one of the reflected light and the transmitted light reflected and transmitted by the half mirror is reflected by the camera. In a coaxial irradiation image pickup device having a light emitting means arranged in a housing so as to be emitted to the outside as a light beam coaxial with the optical axis, reflected light and transmitted light emitted from the light emitting means and reflected and transmitted by a half mirror. Of the other light, an optical attenuation filter disposed on the optical axis of the other light and tilted with respect to the optical axis, and a light attenuation filter disposed on the optical axis of the reflected light reflected by the other light attenuation filter. It is obtained by a painful.

A stray light removing device for a coaxial irradiation image pickup device according to a second invention of the present invention is the one according to the first invention, wherein the half mirror side surface of the light attenuation filter is provided with an antireflection coating. Is.

A stray light removing device for a coaxial irradiation image pickup device according to a third aspect of the present invention includes a housing having an opening, a camera arranged in the housing so that an optical axis passes through the opening, and a light from the camera. The half mirror, which is located in the housing so that it is positioned on the axis, emits the emitted light to the half mirror, and one of the reflected light and the transmitted light reflected and transmitted by the half mirror is coaxial with the optical axis of the camera. In the coaxial irradiation imaging device having a light emitting means arranged in the housing so as to be emitted from the opening as a light flux of
The light emitted from the light emitting means and reflected and transmitted by the half mirror is arranged perpendicular to the optical axis of the other light of the reflected light and the transmitted light, and an antireflection coating is provided on the surface on the half mirror side. The optical attenuation filter is provided.

The stray light removing apparatus for a coaxial irradiation image pickup device according to a fourth aspect of the present invention is the stray light removing device according to the third aspect, wherein the non-reflecting body is emitted from the light emitting means and reflected and transmitted by the half mirror. Also, it is arranged in the subsequent stage of the optical attenuation filter on the optical axis of the other light of the transmitted light.

Further, a stray light removing device for a coaxial irradiation image pickup device according to a fifth aspect of the present invention includes a housing having an opening, a camera arranged in the housing so that an optical axis passes through the opening, and a light from the camera. The half mirror, which is located in the housing so that it is positioned on the axis, emits the emitted light to the half mirror, and one of the reflected light and the transmitted light reflected and transmitted by the half mirror is coaxial with the optical axis of the camera. In the coaxial irradiation imaging device having a light emitting means arranged in the housing so as to be emitted from the opening as a light flux of
The transparent body is arranged on the optical axis of the other of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror, and has a sawtooth-shaped cross section.

A stray light removing device for a coaxial irradiation image pickup device according to a sixth aspect of the present invention is the reflected light according to the fifth aspect, wherein the non-reflecting body is emitted from the light emitting means and reflected and transmitted by the half mirror. And is arranged in the subsequent stage of the transparent body on the optical axis of the other light of the transmitted light.

A stray light removing device for a coaxial irradiation image pickup device according to a seventh aspect of the present invention is a housing having an opening, a camera arranged in the housing so that an optical axis passes through the opening, and a light from the camera. The half mirror, which is located in the housing so that it is positioned on the axis, emits the emitted light to the half mirror, and one of the reflected light and the transmitted light reflected and transmitted by the half mirror is coaxial with the optical axis of the camera. In the coaxial irradiation imaging device having a light emitting means arranged in the housing so as to be emitted from the opening as a light flux of
One end has a large-diameter opening, the other end has a small-diameter opening, and the inner diameter is configured in a trumpet shape that gradually decreases from one end side to the other end side, the axis of which is emitted from the light emitting means and reflected by the half mirror. A mirror that is located on the optical axis of the transmitted reflected light and the other light of the transmitted light, and is arranged so that one end is located on the half mirror side, and on the other side of the mirror on the optical axis of the other light. And a non-reflecting member arranged.

Further, a stray light removing device for a coaxial irradiation image pickup device according to an eighth aspect of the present invention includes a housing having an opening, a camera arranged in the housing so that an optical axis passes through the opening, and a light from the camera. The half mirror, which is located in the housing so that it is positioned on the axis, emits the emitted light to the half mirror, and one of the reflected light and the transmitted light reflected and transmitted by the half mirror is coaxial with the optical axis of the camera. In the coaxial irradiation imaging device having a light emitting means arranged in the housing so as to be emitted from the opening as a light flux of
A light diffusing lens disposed on the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror, and a rear stage of the light diffusing lens on the optical axis of the other light. And a non-reflecting member arranged in the.

A stray light removing device for a coaxial irradiation image pickup device according to a ninth aspect of the present invention is a housing having an opening, a camera arranged in the housing so that an optical axis passes through the opening, and a light from the camera. The half mirror, which is located in the housing so that it is positioned on the axis, emits the emitted light to the half mirror, and one of the reflected light and the transmitted light reflected and transmitted by the half mirror is coaxial with the optical axis of the camera. In the coaxial irradiation imaging device having a light emitting means arranged in the housing so as to be emitted from the opening as a light flux of
A light condensing lens disposed on the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror, and a pinhole, and the pinhole has the other light. A shield plate arranged so as to be located near the condensing point of the light condensing lens on the optical axis of, and a non-reflective body arranged at the latter stage of the shield plate on the optical axis of the other light. It is a thing.

[0015]

In the first aspect of the present invention, the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror reaches the optical attenuation filter, and a part of the light reaches the optical attenuation filter. The light is reflected by the surface of, and the rest enters into the optical attenuation filter and is attenuated. Then, the light reflected on the surface of the light attenuating filter and the light that has not been attenuated in the light attenuating filter reach the non-reflecting body, most of the light is absorbed, and a part of the light becomes scattered light. Then, a part of the scattered light generated by the non-reflecting body reaches the light attenuating filter, a part of the light is reflected by the surface of the light attenuating filter, and the rest enters into the light attenuating filter and is attenuated. Then, the light reflected on the surface of the light attenuating filter and the light that has not been attenuated in the light attenuating filter reach the half mirror, are reflected, and enter the camera as stray light.

Further, in the second invention of the present invention,
When the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror reaches the light attenuation filter, it is not reflected by the surface of the light attenuation filter on the half mirror side, and most of the light is It is incident on the optical attenuation filter. Therefore, the light amount of the other light reaching the non-reflecting body via the light attenuation filter is reduced, and the light amount of the scattered light generated in the non-reflecting body is reduced. Then, when a part of the scattered light generated by the non-reflecting body reaches the light attenuating filter, it is not reflected by the surface of the light attenuating filter on the half mirror side, and most of the light enters the light attenuating filter. Therefore, the amount of scattered light reaching the half mirror via the light attenuation filter is reduced, and stray light entering the camera is reduced.

In the third invention of the present invention,
The other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror reaches the optical attenuation filter and is not reflected on the surface of the optical attenuation filter, and most of them enters the optical attenuation filter. Is attenuated. Then, the light that has not been attenuated in the light attenuation filter reaches the half mirror, is reflected, and enters the camera as stray light.

In the fourth invention of the present invention,
The light that has not been attenuated in the light attenuation filter passes through the light attenuation filter, reaches the non-reflecting body, and most of the light is absorbed. Then, a part of the scattered light generated by the non-reflecting body again passes through the light attenuation filter, reaches the half mirror, is reflected, and is incident on the camera as stray light. Therefore, the amount of light that has passed through the light attenuation filter and is incident on the camera as stray light can be reduced.

In the fifth aspect of the present invention,
The other of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror reaches the transparent body having a sawtooth-shaped cross section, part of which is reflected on the surface, and the rest is refracted and enters the inside. To do. Therefore, the surface and the inside of the transparent body are repeatedly reflected and refracted to be attenuated. Then, the light that cannot be attenuated reaches the half mirror, is reflected, and enters the camera as stray light.

In the sixth aspect of the present invention,
Light that has not been attenuated in the transparent body passes through the transparent body, reaches the non-reflecting body, and most of the light is absorbed. Then, a part of the scattered light generated in the non-reflecting body passes through the transparent body again,
It reaches the half mirror, is reflected, and enters the camera as stray light. Therefore, the amount of light that has passed through the transparent body and is incident on the camera as stray light can be reduced.

According to the seventh aspect of the present invention,
The other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror reaches the mirror,
The light is repeatedly reflected on the inner wall surface of the mirror, is attenuated, and is collected on the other end side. Then, it diffuses from the opening at the other end of the mirror to reach the non-reflecting body, most of it is absorbed, and a part of it becomes scattered light. Then, a part of the scattered light generated by the non-reflector is narrowed down by the opening at the other end of the mirror to reduce the amount of light, reaches the half mirror, is reflected, and is incident as stray light on the camera.

In the eighth aspect of the present invention,
The other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror reaches the light diffusing lens, is diffused by the light diffusing lens and is applied to the non-reflecting body, and most of the light is emitted. Be absorbed. Then, the maximum value of the amount of light per unit area with which the non-reflector is irradiated is reduced, and the generation of scattered light is suppressed. Then, a part of the scattered light generated by the non-reflecting body is diffused by the light diffusing lens, the amount of light reaching the half mirror is reduced, and the light is incident on the camera as stray light.

In the ninth aspect of the present invention,
The other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror reaches the light focusing lens and is focused by the light focusing lens. Then, after passing through the pinholes of the shielding plate, they diffuse and reach the non-reflecting body, most of them are absorbed, and some of them become scattered light.
Then, a part of the scattered light generated by the non-reflecting body is narrowed down by the pinhole of the shielding plate to reduce the amount of light, reaches the half mirror, is reflected, and is incident as stray light on the camera.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation imaging device according to a first embodiment of the present invention. In the figure, the same or corresponding parts as those of the conventional stray light removing device shown in FIG. However, the description is omitted. In the figure, 6 is an optical attenuation filter. For this optical attenuation filter 6, for example, a glass filter in which a color absorption component is added to basic glass to give parallel planarity is used, and the half mirror 2
It is arranged at an angle of 45 ° with respect to the optical axis of the transmitted light so as to block the optical path of the transmitted light of the emitted light from the light emitting diode 3 divided by. Here, the non-reflector 4 is arranged at a position where the light reflected by the light attenuation filter 6 of the transmitted light is incident. In addition, a to n in the figure represent the optical paths of the emitted light emitted from the light emitting diode 3. The rest of the configuration is similar to that of the stray light removing apparatus shown in FIG. 7.

Next, the operation of the first embodiment will be described. The emitted light emitted from the light emitting diode 3 travels along the optical path a, reaches the half mirror 3, and is split into reflected light and transmitted light. The reflected light that has been split is the camera 1
The light travels along the optical path b coaxial with the optical axis of the above, passes through the opening 5a, and is emitted to the outside of the housing 5. On the other hand, half mirror 2
The transmitted light divided by advances in the optical path c and reaches the optical attenuation filter 6. Then, part of the light that has reached the light attenuation filter 6 is reflected by the A surface of the filter, travels along the optical path f, and enters the non-reflecting body 4. The rest of the light enters the filter, travels along the optical path g, and is attenuated. The light that has not been attenuated in the optical path g is reflected by the B surface of the filter, travels along the optical path h, and is attenuated. The light that has not been attenuated in the optical path h travels in the optical path i and enters the non-reflecting body 4. Light that travels along the optical paths f and i and is incident on the non-reflecting body 4 is absorbed by the non-reflecting body 4, and a part thereof becomes scattered light. Then, a part of the scattered light travels along the optical path d and reaches the optical attenuation filter 6. A part of the scattered light reaching the light attenuation filter 6 is reflected on the A surface of the filter, travels along the optical path j, is reflected by the half mirror 2, and travels along the optical path e to enter the camera 1. The rest of the light enters the filter, travels along the optical path k, and is attenuated. The light that has not been attenuated in the optical path k is reflected by the B surface of the filter, travels along the optical path l, and is attenuated. The light that has not been attenuated in the optical path 1 travels in the optical path m, is reflected by the half mirror 2, travels in the optical path n, and enters the camera 1.

As described above, according to the first embodiment, the optical attenuation filter 6 is placed on the optical axis of the transmitted light so that the transmitted light of the emitted light from the light emitting diode 3 divided by the half mirror 2 is blocked. Since they are arranged at an angle of 45 ° with respect to each other, the transmitted light of the emitted light from the light emitting diode 3 divided by the half mirror 2 is attenuated when passing through the light attenuation filter 6, and is reflected by the non-reflecting body 4. The amount of light that reaches is reduced. Further, since the amount of light incident on the non-reflector 4 is reduced, the scattered light emitted by the non-reflector 4 is also reduced. Further, the scattered light generated by the non-reflecting body 4 is attenuated when passing through the light attenuation filter 6. Therefore, the amount of light emitted from the light-emitting diode 3 that passes through the half mirror 2 and enters the camera 1 as stray light is reduced, and deterioration of the image of the camera 1 is suppressed. In addition, the distance between the half mirror 2 and the non-reflector 4 is increased to diffuse the transmitted light split by the half mirror 2 and make it enter the non-reflector 4, or diffuse the scattered light from the non-reflector 4. Therefore, it is not necessary to make the light incident on the half mirror 2 and the size of the device can be reduced.

Embodiment 2 FIG. In the second embodiment, in the stray light removing apparatus according to the first embodiment, the A of the light attenuation filter 6 is used.
It has a non-reflective coating on its surface.

In the second embodiment, the light is emitted from the light emitting diode 3, travels along the optical path a, and reaches the half mirror 2.
The light that has passed through the half mirror 2, travels along the optical path c, and reaches the optical attenuation filter 6 is not reflected by the surface A of the optical attenuation filter 6, and most of it enters the optical attenuation filter 6. Then, the light that has entered the light attenuation filter 6 travels along the optical paths g and h and is attenuated. So, half mirror 2
Of the transmitted light that passes through the optical attenuation filters 6, the proportion of the light that travels the optical paths g and h and the optical path i into the non-reflecting body 4 increases, and the amount of light entering the non-reflecting body 4 is correspondingly increased. The scattered light generated by the non-reflecting body 4 is reduced. Further, the scattered light generated in the non-reflecting body 4, traveling along the optical path d and reaching the optical attenuation filter 6 is also A of the optical attenuation filter 6.
Most of the light is not incident on the surface and is incident on the optical attenuation filter 6. Then, the light that has entered the optical attenuation filter 6 travels along the optical paths k and l and is attenuated. Therefore, of the scattered light generated by the non-reflecting body 4, the proportion of the light that travels through the optical paths k and l and the optical path m in the optical attenuation filter 6 and is incident on the half mirror 2 is increased, and is incident on the camera 1 accordingly. The amount of light emitted is reduced. Therefore, according to the second embodiment, the amount of stray light entering the camera 1 can be reduced as compared with the first embodiment, and the deterioration of the image of the camera 1 can be further suppressed.

Example 3. FIG. 2 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation image pickup device according to a third embodiment of the present invention. In the third embodiment, the light-attenuating filter 6 whose surface A is anti-reflection coated with the anti-reflection coating film 6a blocks the optical path of the transmitted light of the light emitted from the light emitting diode 3 divided by the half mirror 2. Thus, it is arranged orthogonal to the optical axis of the transmitted light. In the figure, a to c, e, g, o, and p represent the optical paths of the emitted light emitted from the light emitting diode 3.

In the third embodiment, the light is emitted from the light emitting diode 3, travels along the optical path a, and reaches the half mirror 2.
The light that has passed through the half mirror 2, travels along the optical path c, and reaches the optical attenuation filter 6 is not reflected by the surface A of the optical attenuation filter 6, and most of it enters the optical attenuation filter 6. Then, the light incident on the optical attenuation filter 6 has an optical path g
To be attenuated. The light that has not been attenuated in the optical path g is reflected by the B surface of the optical attenuation filter 6, travels in the optical path o, and is attenuated. Further, a part of the light that has not been attenuated in the optical path g passes through the B surface of the optical attenuation filter 6, is scattered by the inner wall surface of the housing 5, enters from the B surface of the optical attenuation filter 6, and travels in the optical path o. And then attenuated. Then, the light emitted from the surface A of the light attenuation filter 6 travels along the optical path p, is reflected by the half mirror 2 and travels along the optical path e, and enters the camera 1 as stray light.

Therefore, according to the third embodiment, since the optical attenuation filter 6 having the antireflection coating on the surface A is arranged orthogonal to the optical path c, the light traveling in the optical path c is the light. The proportion of light reflected by the A surface of the attenuation filter 6 is extremely small, and most of the light traveling in the optical path c travels along the optical paths g and o in the optical attenuation filter 6 and is attenuated, and the amount of stray light entering the camera 1 is reduced. Can be reduced.

Example 4. In the third embodiment, the non-reflecting body 4 is not arranged in the subsequent stage of the light attenuation filter 6, but in the fourth embodiment, the non-reflecting body 4 is arranged in the rear stage of the light attenuating filter 6. . In this case, the light passing through the light attenuation filter 6 can be efficiently absorbed by the non-reflecting body 4, and the amount of stray light entering the camera 1 can be reduced accordingly.

Example 5. FIG. 3 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation image pickup device according to a fifth embodiment of the present invention. In FIG. 7, 7 has one end having a large diameter opening and the other end having a small diameter opening. Is a trumpet-shaped mirror that is formed smaller in order from one end side to the other end side, and this mirror 7 is a half mirror with one end side in the optical path of the transmitted light of the light emitted from the light emitting diode 3 divided by the half mirror 2. It is arranged toward 2. Then, the non-reflecting body 4 is arranged at the rear stage of the mirror 7. In addition, a to f in the figure represent optical paths of light emitted from the light emitting diode 3.

In the fifth embodiment, the light is emitted from the light emitting diode 3, travels along the optical path a, and reaches the half mirror 2.
The light that has passed through the half mirror 2, travels along the optical path c, and reaches the mirror 7 is collected on the other end side while being repeatedly reflected on the inner surface of the mirror 7. At this time, the light reflected on the inner surface of the mirror 7 has a large inclination with respect to the optical path c each time it is reflected, diffuses after passing through the opening on the other end side, and becomes non-reflecting body 4.
Incident on. Then, the non-reflector 4 travels along the optical paths c and f.
Most of the light incident on is absorbed by the non-reflecting body 4,
Part of it becomes scattered light. Of this scattered light, only the scattered light that passes through the opening on the other end side of the mirror 7 travels along the optical path d and is reflected directly or within the mirror 7 to reach the half mirror 2 and is reflected by the half mirror 2. Travels along the optical path e and enters the camera 1 as stray light.

As described above, according to the fifth embodiment, since the mirror 7 is formed in a trumpet shape, the light traveling along the optical path c and reaching the mirror 7 is repeatedly reflected on the inner surface of the mirror 7. It is collected on the other end side, diffused from the opening on the other end side of the mirror 7, and enters the non-reflecting body 4. Therefore, the light traveling along the optical path c and reaching the mirror 7 is attenuated each time it is reflected by the inner surface of the mirror, the amount of light incident on the non-reflector 4 is reduced, and the amount of scattered light generated by the non-reflector 4 is reduced. Is reduced. Further, the light collected on the other end side while being repeatedly reflected on the inner surface of the mirror 7 diffuses and enters the non-reflecting body 4 through the opening on the other end side of the mirror 7, and the opening on the other end side of the mirror 7 Since it is formed with a small diameter, the amount of the scattered light generated by the non-reflecting body 4 that travels through the optical path d through the opening on the other end side of the mirror 7 is reduced. Therefore, the amount of stray light reflected by the half mirror 2 and traveling along the optical path e and entering the camera 1 is reduced.

Example 6. 4A and 4B are views showing a stray light removing device of a coaxial irradiation imaging device according to a sixth embodiment of the present invention. FIG. 4A is a schematic configuration diagram and FIG. 4B is an enlarged view of a main part. In the third embodiment, the optical attenuation filter 6 having the anti-reflection coating on the surface A is arranged so that the optical axis of the transmitted light of the emitted light from the light emitting diode 3 divided by the half mirror 2 is blocked. However, in the sixth embodiment, as shown in FIG. 4, a transparent body 8 having a sawtooth cross section, for example, a glass body, is divided by a half mirror 2 to emit light. It is arranged so as to be orthogonal to the optical axis of the transmitted light so as to block the optical path of the transmitted light of the emitted light from the diode 3.

In the sixth embodiment, the light is emitted from the light emitting diode 3, travels along the optical path a, and reaches the half mirror 2.
The light that has passed through the half mirror 2, travels along the optical path c, and reaches the transparent body 8 is reflected by the sawtooth-shaped surface of the transparent body 8 and travels along the optical path r, and is refracted to enter the optical path s. Is divided into light that travels through. The light traveling in the optical paths r and s is
In the same manner, reflection and refraction are repeated to be attenuated.
Then, the light emitted from the transparent body 8 travels along the optical path q to reach the half mirror 2, is reflected by the half mirror 2, travels along the optical path e, and enters the camera 1 as stray light.

As described above, according to the sixth embodiment, since the transparent body 8 having a sawtooth-shaped cross section is arranged orthogonal to the optical path c, the light traveling along the optical path c is transparent. It is attenuated by repeating reflection and refraction on the surface of
The amount of light emitted from the transparent body 8 and traveling along the optical path q to reach the half mirror 2 is reduced, and the amount of stray light incident on the camera 1 can be reduced. Here, the sawtooth shape of the transparent body 8 needs to be designed so that the light traveling in the optical path c is repeatedly reflected and refracted on the surface and inside, and the shape of the optical path c and the sawtooth surface is It is desirable to set the angle θ smaller than 15 °.

Example 7. In the above-mentioned Example 6, the non-reflecting body 4 is not arranged in the subsequent stage of the transparent body 8.
In the seventh embodiment, the non-reflecting body 4 is arranged after the transparent body 8. In this case, the light passing through the transparent body 8 can be efficiently absorbed by the non-reflecting body 4, and the amount of stray light entering the camera 1 can be reduced accordingly.

Embodiment 8 FIG. FIG. 5 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation image pickup device according to an eighth embodiment of the present invention. In FIG. 5, 9 is an optical path of transmitted light of emitted light from a light emitting diode 3 divided by a half mirror 2. It is a lens for light diffusion arranged inside, and for this light diffusion lens 9, for example, a concave lens can be used. Then, the non-reflecting body 4 is arranged at the subsequent stage of the light diffusing lens 9. In the figure, a to e, t, and u represent optical paths of light emitted from the light emitting diode 3.

In the eighth embodiment, the light is emitted from the light emitting diode 3, travels along the optical path a, and reaches the half mirror 2.
The light that has passed through the half mirror 2, travels along the optical path c, and reaches the light diffusing lens 9 is diffused by the light diffusing lens 9,
The light travels along the optical path t and is incident on the non-reflecting body 4. Then, most of the light that travels along the optical path t and is incident on the non-reflecting body 4 is absorbed by the non-reflecting body 4, and a part thereof becomes scattered light. A part of this scattered light travels along the optical path d, reaches the light diffusing lens 9, and is diffused by the light diffusing lens 9. Then, a part of the diffused light travels along the optical path u to reach the half mirror 2, is reflected by the half mirror 2, travels along the optical path e, and enters the camera 1 as stray light.

As described above, according to the eighth embodiment, since the light diffusing lens 9 is arranged in the optical path c, the optical path c
The light that travels in the direction of is diffused and enters the non-reflecting body 4. Then, a part of the scattered light generated by the non-reflecting body 4 travels along the optical path d and reaches the light diffusing lens 9 to be diffused. Therefore,
Only part of the scattered light diffused by the light diffusing lens 9 travels along the optical path u and reaches the half mirror 2, is reflected by the half mirror 2 and travels along the optical path e, and enters the camera 1. The amount of stray light is reduced.

Embodiment 9 FIG. FIG. 6 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation imaging device according to a ninth embodiment of the present invention. In FIG. 6, 10 is an optical path of transmitted light of emitted light from a light emitting diode 3 divided by a half mirror 2. This is a light condensing lens disposed inside, and as the light condensing lens 10, for example, a convex lens can be used. Reference numeral 11 denotes a shield plate having a pinhole 11a. The shield plate 11 is arranged in the vicinity of the condensing point of the light condensing lens 10 with the center of the pinhole 11a passing through the optical axis of the light condensing lens 10. Then, the non-reflecting body 4 is arranged at the subsequent stage of the shielding plate 11. In the figure, a to e, v, and w represent the optical paths of the light emitted from the light emitting diode 3.

In the ninth embodiment, the light is emitted from the light emitting diode 3, travels along the optical path a, and reaches the half mirror 2.
The light that has passed through the half mirror 2, travels along the optical path c and reaches the light condensing lens 10, passes through the light condensing lens 10 and is condensed, and travels along the optical path v to the non-reflecting body 4. It is incident. Then, most of the light that travels along the optical path v and is incident on the non-reflecting body 4 is absorbed by the non-reflecting body 4, and a part thereof becomes scattered light. Part of this scattered light travels on the optical path d to reach the light condensing lens 10, passes through the light condensing lens 10 and travels on the optical path w to reach the half mirror 2, and is reflected by the half mirror 2. Then, the light travels along the optical path e and enters the camera 1 as stray light. At this time, the scattered light traveling along the optical path d reaches only the light condensing lens 10 passing through the pinhole 11a of the shield plate 11, and the light condensing lens 1
The amount of light reaching 0 is reduced.

As described above, according to the ninth embodiment, the light condensing lens 10 is arranged in the optical path c, and the shield plate 11 having the pinhole 11a near the converging point of the light condensing lens 10 is provided. Is arranged, the light that has traveled along the optical path c is condensed by the light condensing lens 10, passes through the pinhole 11a without being reflected by the shielding plate, and is incident on the non-reflecting body 4 to cause no reflection. When a part of the scattered light generated in the body 4 travels on the optical path d, only the scattered light passing through the pinhole 11a reaches the light condensing lens 10, and the stray light incident on the camera 1 is The amount of light is reduced.

In each of the above embodiments, the emitted light emitted from the light emitting diode 3 is split by the half mirror 2 into reflected light and transmitted light, and the reflected light is emitted to the outside through the opening 5a. Is to be reduced as a component of stray light, but the same effect can be obtained even if the transmitted light is emitted to the outside through the opening 5a and the reflected light is reduced as a component of stray light. .

Further, in each of the above-mentioned embodiments, the coaxial irradiation image pickup device is described as being mounted on an automobile to detect the dozing state of the driver, but the coaxial irradiation image pickup device is not limited to this. Instead, it can be applied to, for example, a microscope irradiation device.

[0048]

Since the present invention is configured as described above, it has the following effects.

According to the first aspect of the present invention, the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror is tilted with respect to the optical axis. Since it is equipped with an optical attenuation filter and a non-reflective material that is placed on the optical axis of the reflected light reflected by the other optical attenuation filter, the stray light removal rate is secured and downsizing is achieved. It is possible to obtain a stray light removing device for a coaxial irradiation image pickup device.

According to the second invention of the present invention, in the first invention, since the surface of the optical attenuation filter on the half mirror side is provided with a non-reflective coating, the reflection on the surface of the optical attenuation filter is achieved. Can be suppressed, and the stray light removal rate can be increased accordingly.

According to the third aspect of the present invention, the other of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror is perpendicular to the optical axis. Since the light attenuating filter which is disposed in the above and has a non-reflection coating on the surface on the half mirror side is provided, the same effect as that of the first invention can be obtained.

According to a fourth aspect of the present invention, in the third aspect, the non-reflecting body emits the other light of the reflected light and the transmitted light which are emitted from the light emitting means and reflected and transmitted by the half mirror. Since it is arranged on the optical axis after the light attenuating filter, the light passing through the light attenuating filter can be absorbed by the non-reflecting body, and the stray light removal rate can be increased accordingly.

According to the fifth aspect of the present invention, the other of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror is disposed on the optical axis,
Since the transparent body having a sawtooth-shaped cross section is provided, the same effect as that of the first invention can be obtained.

Further, according to the sixth invention of the present invention, in the fifth invention, the non-reflecting body emits the other light of the reflected light and the transmitted light reflected and transmitted by the half mirror from the light emitting means. Since it is arranged on the optical axis in the latter stage of the transparent body, the light passing through the transparent body can be absorbed by the non-reflecting body, and the stray light removal rate can be increased accordingly.

According to the seventh aspect of the present invention, one end has a large-diameter opening, the other end has a small-diameter opening, and the inner diameter is gradually reduced from one end to the other end. Is arranged such that its axis is located on the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror, and one end is located on the half mirror side. Since the mirror and the non-reflector arranged on the optical axis of the other light in the latter stage of the mirror are provided, the same effect as that of the first invention can be obtained.

According to the eighth aspect of the present invention, the light diffusing lens disposed on the optical axis of the other of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror. And the non-reflecting body arranged at the rear stage of the light diffusing lens on the optical axis of the other light, the same effect as the first invention can be obtained.

According to the ninth aspect of the present invention, the light condensing unit is arranged on the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror. On the optical axis of the other light, a lens and a shield plate that has a pinhole and is arranged so that the pinhole is located near the focal point of the light condensing lens on the optical axis of the other light Since it has a non-reflective material arranged in the latter part of the shielding plate,
The same effects as those of the first aspect can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation imaging device according to a first embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation imaging device according to a third embodiment of the present invention.

FIG. 3 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation imaging device according to a fifth embodiment of the present invention.

FIG. 4 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation imaging device according to a seventh embodiment of the present invention.

FIG. 5 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation imaging device according to an eighth embodiment of the present invention.

FIG. 6 is a schematic configuration diagram showing a stray light removing device of a coaxial irradiation imaging device according to a ninth embodiment of the present invention.

FIG. 7 is a schematic configuration diagram showing a stray light removing device of a conventional coaxial irradiation imaging device.

[Explanation of symbols]

1 camera, 2 half mirror, 3 light emitting diode (light emitting means), 4 non-reflector, 5 housing, 5a
Aperture, 6 light attenuation filter, 6a anti-reflection coating film, 7 mirror, 8 transparent body, 9 light diffusion lens, 1
0 light condensing lens, 11 shielding plate, 11a pinhole.

Claims (9)

[Claims] 1. A housing having an opening, a camera arranged in the housing so that an optical axis passes through the opening, and a half mirror arranged in the housing so as to be located on the optical axis of the camera. And irradiate the emitted light to the half mirror so that one of the reflected light and the transmitted light reflected and transmitted by the half mirror is emitted to the outside from the opening as a luminous flux coaxial with the optical axis of the camera. In a coaxial irradiation image pickup device having a light emitting means arranged in the housing, the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror is on the optical axis. And a non-reflector arranged on the optical axis of the reflected light of the other light reflected by the optical attenuation filter. Stray light removal device for coaxial irradiation image pickup device. 2. The stray light removing device of the coaxial irradiation imaging device according to claim 1, wherein a surface of the light attenuation filter on the half mirror side is provided with a non-reflection coating. 3. A housing having an opening, a camera arranged in the housing so that an optical axis passes through the opening, and a half mirror arranged in the housing so as to be located on the optical axis of the camera. And irradiate the emitted light to the half mirror so that one of the reflected light and the transmitted light reflected and transmitted by the half mirror is emitted to the outside from the opening as a luminous flux coaxial with the optical axis of the camera. In a coaxial irradiation image pickup device having a light emitting means arranged in the housing, the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror is on the optical axis. A coaxial irradiation imaging device, characterized in that the coaxial irradiation imaging device is equipped with an optical attenuation filter that is disposed perpendicular to the optical axis and has a non-reflection coating on the surface on the half mirror side. Stray light removal device. 4. A non-reflecting body is arranged at a stage subsequent to the optical attenuation filter on the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror. The stray light removing device of the coaxial irradiation imaging device according to claim 3. 5. A housing having an opening, a camera arranged in the housing such that an optical axis passes through the opening, and a half mirror arranged in the housing so as to be located on the optical axis of the camera. And irradiate the emitted light to the half mirror so that one of the reflected light and the transmitted light reflected and transmitted by the half mirror is emitted to the outside from the opening as a luminous flux coaxial with the optical axis of the camera. In a coaxial irradiation image pickup device having a light emitting means arranged in the housing, the coaxial irradiation imaging device is arranged on the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror, A stray light removing device for a coaxial irradiation image pickup device, comprising a transparent body having a sawtooth cross section. 6. A non-reflecting body is arranged at a rear stage of the transparent body on the optical axis of the other light of the reflected light and the transmitted light which is emitted from the light emitting means and reflected and transmitted by the half mirror. The stray light removing device of the coaxial irradiation imaging device according to claim 5. 7. A housing having an opening, a camera arranged in the housing so that an optical axis passes through the opening, and a half mirror arranged in the housing so as to be located on the optical axis of the camera. And irradiate the emitted light to the half mirror so that one of the reflected light and the transmitted light reflected and transmitted by the half mirror is emitted to the outside from the opening as a luminous flux coaxial with the optical axis of the camera. A coaxial irradiation image pickup device having a light emitting means arranged in the housing, wherein one end has a large-diameter opening, the other end has a small-diameter opening, and the inner diameter is gradually reduced from one end side to the other end side. And its axis is located on the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror, and
A coaxial irradiation image pickup device comprising a mirror arranged so that one end thereof is located on the half mirror side, and a non-reflector arranged on the optical axis of the other light after the mirror. Stray light removal device. 8. A housing having an opening, a camera arranged in the housing so that an optical axis thereof passes through the opening, and a half mirror arranged in the housing so as to be located on the optical axis of the camera. And irradiate the emitted light to the half mirror so that one of the reflected light and the transmitted light reflected and transmitted by the half mirror is emitted to the outside from the opening as a luminous flux coaxial with the optical axis of the camera. In a coaxial irradiation image pickup device having a light emitting means arranged in the housing, the coaxial irradiation image pickup device is arranged on the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror. A light diffusion lens,
A stray light removing device for a coaxial irradiation image pickup device, comprising: a non-reflecting member arranged in a rear stage of the light diffusing lens on the optical axis of the other light. 9. A housing having an opening, a camera arranged in the housing such that an optical axis thereof passes through the opening, and a half mirror arranged in the housing so as to be located on the optical axis of the camera. And irradiate the emitted light to the half mirror so that one of the reflected light and the transmitted light reflected and transmitted by the half mirror is emitted to the outside from the opening as a luminous flux coaxial with the optical axis of the camera. In a coaxial irradiation image pickup device having a light emitting means arranged in the housing, the coaxial irradiation image pickup device is arranged on the optical axis of the other light of the reflected light and the transmitted light emitted from the light emitting means and reflected and transmitted by the half mirror. A light condensing lens,
On the optical axis of the other light, there is a pinhole, and the pinhole is arranged so that the pinhole is located near the condensing point of the light condensing lens on the optical axis of the other light. And a non-reflecting member arranged in the latter stage of the shielding plate.