JPH05232212A - Reception optical system - Google Patents

Abstract

(57) [Abstract] [Purpose] After mounting the light receiving element in the receiving optical system that photoelectrically converts light of a specific wavelength within the viewing angle, remove the light receiving element and adjust the position again when checking the receiving optical axis. The purpose is to obtain a receiving optical system that does not need to perform. [Structure] The lens barrel is divided at a portion where the received light between the relay lenses 5 and 6 of the receiving optical system is parallel light, and the parallel light is input from the relay lens 5 to the objective lens 1 side to receive optical axis 13 To confirm. After confirmation, the lens barrels 15 and 16 are combined, but the position of the light receiving element 9 is not moved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a receiving optical system such as a laser range finder for transmitting a pulsed laser to a target and measuring the time until the reflected light returns. The present invention relates to a receiving optical system for selectively photoelectrically converting light of a certain wavelength.

[0002]

2. Description of the Related Art FIG. 5 is a diagram showing a conventional receiving optical system and a conventional method for adjusting a position of a light receiving element, and FIG. 6 is a diagram showing a method for confirming a receiving optical axis. In FIG.
Is a lens barrel, 4 is a pinhole, 5 and 6 are relay lenses, 7 is a narrow band filter installed between the relay lenses 5 and 6, and
Reference numeral 9 is a light receiving element, 10 is a light receiving element supporting plate for mounting the light receiving element 9 and further fixing the whole to the lens barrel 3, 11 is a light receiving element terminal, 12 is a light receiving element light receiving portion, 13 is a receiving optical axis, 14
Is an autocollimator.

Next, the operation will be described. The light propagating in the medium is condensed by the objective lens 1 into the pinhole 4 at the focal position. The reception visual field at this time is given by the following equation, where f is the length from the objective lens 1 to the pinhole 4 and D is the diameter of the pinhole 4. tan ^-1 (D / f)

The light passing through the pinhole 4 is collimated by the relay lens 5 and enters the narrow band filter 7 vertically. This is because the narrow band filter 7 limits the wavelength of transmitted light by utilizing the interference effect of light, and therefore it is necessary to make the incident angle of light constant. After the wavelength is selected by the narrow band filter 7, it is condensed again by the relay lens 6 and photoelectrically converted by the light receiving section 12 of the light receiving element 9 arranged at the focal position of the relay lens 6. Size of light receiving part 12 Pinhole 4
When the diameter is equal to or smaller than the diameter of the light receiving element, the position of the light receiving element 9 needs to be accurately adjusted to obtain a sufficient light receiving element output. This is because adjustment is unnecessary if the dimensions of the lens barrel 3 are defined so that the position of the light receiving element 9 in the direction of the reception optical axis 13 matches the light receiving portion 12 with the focal plane determined by the relay lens 6. Light is introduced behind the lens 1, the light receiving element support plate 10 is moved within the mounting surface of the lens barrel 3, and the light receiving element terminal 11 is fixed to the lens barrel 3 at a position where the output is maximum.

When checking the reception optical axis 13, for example,
When it is used in a laser range finder and is attempted to be aligned with the laser transmission axis, the light receiving element 9 together with the support plate 10 are attached to the lens barrel 3.
6, the light is input from the light receiving element 9 side as shown in FIG. 6, and the position and angle of the collimator 14 are adjusted so that the optical axis formed by the collimator 14 and the reception optical axis 13 are parallel to each other outside the objective lens 1. Confirm by doing so. At this time, the reception optical axis 13 coincides with the center of the pinhole image. In order to confirm the reception optical axis 13 after the light receiving element 9 is attached, it is necessary to remove the light receiving element 9 and then confirm the reception optical axis 13 as shown in FIG. 4 and adjust the position of the light receiving element 9 again. is there.

[0006]

Since the conventional receiving optical system is constructed as described above, it is necessary to remove the light receiving element every time the receiving optical axis is confirmed. If the size of the light receiving part of the light receiving element is equal to or smaller than the diameter of the pinhole, it was necessary to readjust the position of the light receiving element to obtain a sufficient light receiving element output after checking the optical axis. ..

Further, it is necessary to adjust the position of the light receiving element by introducing light from the objective lens side. Furthermore, if the size of the light receiving element is equal to or smaller than the diameter of the pinhole, the light passing through the pinhole must be used to accurately adjust the position of the light receiving element so that sufficient light receiving element output can be obtained. I have to. However, it is necessary to uniformly illuminate the entire pinhole in order to confirm that it is possible to receive the light in all the receiving fields of view. This requires illumination with a uniform intensity distribution with a wide field of view from the objective lens. Had to do. Also, the receiving optical axis could not be adjusted.

The present invention has been made to solve the above problems, and an object thereof is to obtain a receiving optical system capable of confirming a receiving optical axis without removing a light receiving element.

Further, according to the present invention, it is possible to obtain a receiving optical system in which the position of the light receiving element can be accurately adjusted and the receiving optical axis can be adjusted without using an illuminating device having a uniform intensity distribution having a spread corresponding to the field of view. Has a purpose.

[0010]

The receiving optical system according to the present invention is such that the lens barrel can be divided between two relay lenses and can be separated even after the position adjustment of the light receiving element.

Further, the receiving optical system according to the present invention can be divided into a lens barrel, an objective lens and a pinhole.

[0012]

In the receiving optical system according to the present invention, the lens barrel is divided even after the position of the light receiving element is adjusted, and light is input from the narrow band filter side to confirm the pinhole image, that is, the receiving optical axis can be confirmed. After that, by joining the lens barrels, the receiving optical axis can be confirmed without changing the position of the light receiving element.

In the receiving optical system of the present invention, the position of the light receiving element can be adjusted and confirmed by scattered light like a general white light source. Also, the reception optical axis can be adjusted and confirmed.

[0014]

【Example】

Example 1. An embodiment of the present invention will be described below. Figure 1
In FIG. 2, 1 to 14 are the same as those in FIGS. 5 and 6. Reference numeral 15 is a lens barrel holding the objective lens 1, the pinhole 4 and the relay lens 5, 16 is a narrow band filter 7 and the relay lens 6, and a light receiving element support plate 10 having a light receiving element 9 attached to one end face is fixed. In the lens barrel, the lens barrel 15 and the lens barrel 16 can be joined and separated by making the relay lens 5 and the narrow band filter 7 face each other.

Next, the operation will be described. The light propagating through the medium is condensed on the pinhole 4 at the focal position of the objective lens 1. The reception visual field at this time is determined by the length from the objective lens 1 to the pinhole 4 and the diameter of the pinhole 4. The light that has passed through the pinhole 4 is collimated by the relay lens 5 that is placed away from the pinhole 4 by its focal length. Here, the objective lens 1 to the relay lens 5 are held by the lens barrel 15. The received light that has become parallel light is vertically incident on the narrow band filter 7, the wavelength is selected by the narrow band filter 7, and the light is condensed again by the relay lens 6, and the light receiving portion 12 of the light receiving element 9 is focused on the relay lens 6. It is placed at a position to photoelectrically convert received light. Here, the narrow band filter 7 and the relay lens 6 are held by the lens barrel 16. Light is received from the objective lens 1 at the position of the light receiving element 9, and the light receiving element support plate 10 having the light receiving element 9 attached thereto is moved within the support plate mounting surface of the lens barrel 16 so that the output of the light receiving element terminal 11 is maximized. The support plate 10 is fixed to the lens barrel 16 and fitted. This is because adjustment of the position of the light receiving element 9 in the direction of the reception optical axis 13 becomes unnecessary if the size of the lens barrel 3 is defined so that the light receiving unit 12 becomes the focal plane of the relay lens 6.

When confirming the light receiving optical axis 13, for example,
When it is used in a laser range finder and it is attempted to align with the laser transmission axis, the lens barrel 15 and the lens barrel 16 are divided, parallel light is input from the relay lens 5 side as shown in FIG.
The image of is confirmed by adjusting the position and angle of the collimator 14. After confirmation, the lens barrel 15 and the lens barrel 16 are joined. At this time, since the lens barrel is divided at the portion where the received light is parallel light, the mounting accuracy at the time of joining does not depend on the translational direction of the receiving optical axis 13 and is determined by the lens barrel 15 with respect to the receiving optical axis 13. It depends only on the inclination of the lens barrel 16, that is, the twist caused by the rotation of the lens barrel 15 and the lens barrel 16. This can be minimized by using a mechanism that suppresses rotation at the joint, for example, by using a guide pin, or by arranging the mounting bolts at the time of joining unevenly. The narrow band filter 7 may be placed in either the lens barrel 15 or the lens barrel 16, but if the parallel white light is moved from the lens barrel 16 side to the lens barrel 15 side and is passed through the filter 7, the reception optical axis can be seen. it can.

Embodiment 2. Next, a second embodiment of the present invention will be described. In FIGS. 3 and 4, 15 is a lens barrel holding the objective lens 1, 16 is a pinhole 4 and a relay lens 5.
And a narrow-band filter 7 and a relay lens 6, and a lens barrel for fixing a light-receiving element support plate 10 having a light-receiving element 9 attached to one end face thereof. The lens barrel 15 and the lens barrel 16 connect the objective lens 1 and the pinhole 4 respectively. Can be joined and separated by facing each other.

Next, the operation will be described. The light propagating through the medium is condensed on the pinhole 4 on the focal plane of the objective lens 1. The receiving field of view at this time is the objective lens 1.
To the pinhole 4 and the diameter of the pinhole 4. The light that has passed through the pinhole 4 is collimated by the relay lens 5 that is placed away from the pinhole 4 by its focal length. The narrow band filter 7 converts the received light that has become parallel light.
Incident perpendicularly to, and after selecting the wavelength with the narrow band filter 7,
The light is condensed again by the relay lens 6, the light receiving portion 12 of the light receiving element 9 is arranged at the focal position of the relay lens 6, and the received light is photoelectrically converted. Here, the objective lens 1 is held by the lens barrel 16, and the pinhole 4 to the relay lens 6 are held by the lens barrel 16.

When the position of the light receiving element 9 is adjusted, FIG.
With the lens barrel 15 and the lens barrel 16 separated from each other, light is input from the pinhole 4 and the light receiving element support plate 10 having the light receiving element 9 attached thereto is moved within the support plate mounting surface of the lens barrel 16.
The support plate 10 is placed at a position where the output of the light receiving element terminal 11 is maximum.
Is fixed to the lens barrel 16 and is aligned. This is because adjustment of the position of the light receiving element 9 in the direction of the reception optical axis 13 becomes unnecessary if the size of the lens barrel 3 is defined so that the light receiving unit 12 becomes the focal plane of the relay lens 6. The light entering through the pinhole 4 may be white light having a wavelength that can be transmitted by the filter 7 as scattered light that illuminates the entire pinhole.

When adjusting the reception optical axis 13, for example,
When it is used in a laser side distance device and is intended to be aligned with the laser transmission axis, the light receiving element 9 together with the support plate 10 are attached to the lens barrel 1.
6, the light is input from the light receiving element 9 side, and the optical axis formed by the collimator 14 and the receiving optical axis 13 are provided outside the objective lens 1.
This is confirmed by adjusting the position and angle of the collimator 14 so that are parallel to each other. At this time, the reception optical axis 13
Coincides with the center of the pinhole image. The adjustment is performed by moving and fixing the position of the lens barrel 16 with respect to the lens barrel 15. At this time, if the joint between the lens barrel 15 and the lens barrel 16 is made parallel to the focal plane of the objective lens 1, the pinhole 4 moves on the focal plane and the receiving field of view does not change.

[0021]

As described above, according to the present invention, the receiving optical axis can be confirmed without removing the light receiving element from the receiving optical system, and it is possible to eliminate the need to readjust the light receiving element mounting position after the confirmation. There is.

Further, according to the present invention, there is an effect that the position of the light receiving element can be adjusted by the white scattered light and the receiving optical axis can be adjusted.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a diagram showing a receiving optical axis confirmation operation according to the second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a light receiving element position adjusting method according to a second embodiment of the present invention.

FIG. 5 is a diagram showing a conventional example.

FIG. 6 is a diagram showing a receiving optical axis confirmation method of a conventional example.

[Explanation of symbols]

 1 Objective Lens 4 Pinhole 5 Relay Lens 6 Relay Lens 7 Narrow Band Filter 9 Light-Receiving Element 10 Light-Receiving Element Support Plate 11 Light-Receiving Element Terminal 12 Light-Receiving Section 13 Receiving Optical Axis 14 Collimator 15 Lens Barrel 16 Lens Barrel

Claims (2)

[Claims] 1. A two-group relay lens provided on the opposite side of the objective lens from a pinhole at the focal position of the objective lens, a narrow band filter provided between the relay lenses, and a focus of the relay lens. In a receiving optical system including a light receiving element provided at a position, a lens barrel can be divided between the relay lens and the narrow band filter, and the receiving optical axis can be confirmed using the objective lens side of the divided relay lens. A receiving optical system characterized by the above. 2. A two-group relay lens provided on the opposite side of the objective lens from a pinhole at the focal position of the objective lens, a narrow band filter provided between the relay lenses, and a focus of the relay lens. In a receiving optical system including a light receiving element provided at a position, a lens barrel is divided between the pinhole and the objective lens, and a relay lens side is used from the divided pinhole to determine the receiving optical axis and the light receiving element position. A receiving optical system characterized in that it can be checked and adjusted.