JPS60135880A - Light wave distance measuring apparatus - Google Patents

Abstract

PURPOSE:To attain to enhance distance measuring accuracy by facilitating assembling adjustment, by such simple constitution that an auxiliary lens is arranged between a light path divider and integrally arranged transmitted and received light reflective members and reflective surfaces of both reflective parts are mutually crossed at right angles. CONSTITUTION:A light path divider 6 having a dichroic mirror surface D reflecting infrared rays but transmitting visible light is arranged between an objective lens 1 and a focusing lens 2 and infrared rays used in measuring a distance are totally reflected by an incident surface 6a and transmit an emitting surface 6c while visible light for collimation transmits an emitting surface 6b. A negative lens 7 is provided between the light path divider 6 and integrally arranged transmitted and received light reflective members 8, 9 to form an afocal system and transmitting and receiving light paths due to both reflective members 8, 9 together cross the optical axis of the objective lens 1 at right angles and arranged on the same straight line. Therefore, because the element groups of each optical system are made independent so as to interpose parallel luminous flux being a boundary therebetween and easy assembling adjustment is enabled, distance measuring accuracy can be enhanced by simple constitution.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to a light wave distance measuring device in which the objective lens of a reference optical system is also used as a light wave distance measuring optical system. The present invention relates to a coaxial type optical distance measuring device in which the other semicircular side is used for receiving light.

(Background of the Invention) Conventionally, various types of light wave distance measuring devices have been known in which the objective lens of the reference optical system is also used as a light wave distance measurement optical system, and various types of light wave distance measurement optical system configurations have been put into practical use. There is. In order to maintain high distance measurement accuracy, it is of course necessary to prevent noise light from being mixed into the received light, but it is also necessary to precisely align the transmitting optical path and the receiving optical path. The manufacturing, assembly, and adjustment involved great difficulties. Further, in order to facilitate adjustment, it is possible to provide a dedicated section for each optical system, but this tends to result in a complicated configuration and the overall configuration of the device to become large.

(Objective of the Invention) The object of the present invention is to provide excellent distance measurement accuracy while also providing easy assembly and
An object of the present invention is to provide a light wave distance measuring device that is easy to adjust and has a simple configuration.

(Summary of the Invention) The present invention has a reference optical system in which an objective lens, a focusing lens, and an eyepiece are arranged in sequence, an optical path splitter arranged between the objective lens and the focusing lens, and an optical path splitter arranged between the objective lens and the focusing lens. A transmitted light reflecting member and a received light reflecting member are integrally arranged on the optical axis of the objective lens in an optical path branched by an optical path splitter, and a light source that supplies transmitted light to the transmitted light reflecting member and the receiving unit. In a coaxial optical wave quasi-single-range device having a light receiving member that receives a light beam from a light reflecting member, between the optical path splitter and the transmitted light reflecting member and the received light reflecting member that are integrally arranged, By arranging an auxiliary lens, the objective lens and the auxiliary lens form an afocal system, and the incident surfaces of the transmitted light reflecting member and the received light reflecting member are orthogonal to each other. .

(Example) Hereinafter, the present invention will be explained based on Examples.

FIG. 1 is an optical path diagram showing the configuration of an embodiment of a light wave distance measuring device according to the present invention. Objective lens (1), focusing lens (2)
), an erecting prism (3), a focusing plate (4), and an eyepiece (5) are arranged in this order to constitute a reference optical system.

An optical path splitter (6) having a dichroic mirror surface for reflecting infrared light and transmitting visible light is arranged between the objective lens (1) and the focusing lens (2).

The optical path splitter (6) consists of a rectangular prism P1 and a trapezoidal prism P that are bonded together with an inclined surface serving as a dichroic mirror surface.
2, an entrance surface (62) perpendicular to the optical axis A of the objective lens (, 1), and a first exit surface (6b) parallel to this.
have. The dichroic ink mirror surface, which serves as a semi-transparent mirror surface, has the function of reflecting infrared light and transmitting visible light at the same time.The infrared light reflected here is totally reflected on the incident surface (6a), and then passes through the table. The light passes through the second exit surface (6c) corresponding to the slope of the shape prism P2. Therefore, the first exit surface (6
Visible light for reference is emitted from b), and the second exit surface (6c
) emits infrared light for distance measurement.

Here, the incident angle θ of the dichroic ink mirror surface, that is, the angle between the optical axis A of the objective lens (1) and the normal to the dichroic mirror surface is determined as follows.

First, regarding the lower limit of θ, in order to make the optical path splitter compact, the incident surface (6a) of the optical path splitter separates the incident light flux from the objective lens (1) and the reflected light flux from the dichroic mirror surface. They must be superimposed, and for this purpose the entrance surface must be a transparent total reflection surface rather than a mirror surface. Therefore, subject to the restriction of the critical angle at the entrance plane (6a),
When the refractive index of the prism P2 is n, as θ becomes smaller, the optical path of the ranging light exiting the optical path splitter (6) becomes nearly parallel to the optical axis of the reference optical system;
This makes it difficult to arrange the distance measuring optical element group including the transmitted light reflecting member (8), the received light reflecting member (9), the transmitting lens (11), the receiving lens (12), and the like.

On the other hand, regarding the upper limit of θ, ■ The larger θ is, the thickness in the optical axis direction of the optical path splitter for branching the optical path of the ranging optical system from the optical path of the reference optical system, that is, the thickness of the incident surface (6a
) and the first exit surface (6b) becomes large, making the reference optical system elongated. Also, ■ Point Q, where the optical axis of the distance measuring optical system reflected by the dichroic mirror surface intersects the entrance surface (6a) as a total reflection surface, is the point Q where the optical axis of the distance measuring optical system reflected by the dichroic mirror surface intersects with the incident surface (6a), which is the total reflection surface. Since it is far from the axis, the second prism P2 becomes large and the entire device becomes large. Furthermore, ■ Thin [1 as well known in 4 technologies]
Furthermore, if the incident angle θ is large (the characteristics of the guichroic mirror will deteriorate, the incident angle cannot be made very large, and manufacturing becomes difficult).

From the above point of view, it is desirable that the angle θ between the normal line of the dichroic mirror surface and the optical axis of the objective lens be set in the range of 15° <θ ~ 45°; In the example, θ is 3
A 0 degree configuration was adopted.

Now, on the optical path of the ranging optical system branched by the optical path splitter (6) consisting of a prism having a gicchroic mirror surface as described above, there is a negative lens (7) as an auxiliary lens.
), and the objective lens (1) and this negative lens form a so-called Galilean afocal system. Therefore, a beam of light from an object at infinity that enters the objective lens (1) becomes a parallel beam of light after exiting from the negative lens (7).

On the optical path of such a parallel light beam, a transmitted light reflecting member (8) for reflecting the transmitted light and a received light reflecting member (9) for reflecting the received light with the optical axis A as a boundary are provided. It is being The transmitted light reflecting member (8) has an entrance surface (8a) and an exit surface (8b) that are orthogonal to each other, and the 45-degree slope (8C) is coated with silver which has high reflectance in the infrared region and visible region. It has a mirror on the back. It is sufficient for this reflective surface to reflect only the infrared region for light wave distance measurement, but it is more convenient to make adjustments in the visible range for manufacturing adjustments. It is also effective to increase the reflectance of The transmitted light reflecting member (8) is joined and supported by a slope (8C) to a 45-degree first slope (9a) formed on the received light reflecting member (9).

The received light reflecting member (9) is arranged in a direction opposite to the first slope (9a).
It has a second slope (9b) formed on the surface reflective surface at an angle of 5 degrees, and this second slope (9b) is a surface mirror on which a thin film is deposited to maximize the reflectance of infrared light for distance measurement. It is formed as. The optical path of the transmitted light and the optical path of the received light by both reflecting members are arranged so that they are perpendicular to the optical axes of the objective lens (1) and the negative lens (7) and are located on the same straight line.

The transmitting light optical path and the receiving light optical path, which are branched from each other by the transmitting light reflecting member (8) and the receiving light reflecting member (9), still maintain a parallel light flux, and there is a positive transmitting lens in the transmitting light optical path. (11), a receiving positive lens (12) is arranged in each receiving light optical path. A light emitting diode (10) as a light source is provided on the focal point of the positive lens for transmission (1), and a positive lens for reception (12)
A photodiode (13) is placed on the focal point as a light receiving member.
) is provided. Here, a light source (10), a transmitting lens (11), a transmitting light reflecting member (8), a negative lens (7)
, the optical path splitter (6), and the objective lens (1) form the transmission optical path of the ranging optical system.
6), a negative lens (7), a received light reflecting member (9), a receiving lens (12), and a light receiving member (13) form a receiving optical path of the ranging optical system. Further, the light receiving member (13) is connected from the light source (10) to the transmitting lens (11) and the receiving lens (12).
) forms a reference light path. In this embodiment, the inclination angles of the reflective surfaces of the transmitted light reflecting member (8) and the received light reflecting member (9) were both 45 degrees with respect to each incident surface, but the angle is not limited to this angle. Without,
As long as the reflective surfaces of both reflective members are perpendicular to each other, the optical axes of the transmitting lens (11) and receiving lens (12) can be aligned on the same straight line, so that the reference light optical system can be connected to the transmitting and receiving destination optical system. It can be completely shared with a part of the reference light optical path, and there is no need to provide any dedicated member as the reference light optical path, resulting in an extremely simple configuration.

In the basic configuration of such a distance measuring optical system, there is a background between the received light reflecting member (9) and the receiving lens (12) for cutting light of wavelengths other than the received light that enters as noise. A light cut filter (14) is arranged. In order to switch between the transmission light and the reference light, an optical path switcher (15) rotatable about a rotation axis eccentric from the optical axis of the transmission lens connects the light source (10) and the transmission lens (
A rotating filter (16) is provided between the receiving lens (11) and the receiving lens (12) to equalize the intensity of the received light and the reference light.
) and the light receiving member (13). Also,
A light shielding plate arranged along the optical axis of the objective lens (1) and the negative lens (7) so that the transmitted light does not directly enter the receiving optical path or the reference optical path, and the reference light does not enter the receiving optical path. (17) is provided. As shown in the side view of FIG. 2(A) and the plan view of FIG. 2(B), the light shielding plate (17) has an opening (17a) in the center for passing the reference light.
, and a portion (1) near the optical axis at the end on the negative lens (7) side.
7b) is formed at a bent portion to prevent the light beam near the optical axis from entering the receiving optical path.

between the transmitting lens (11) and the negative lens (7), between the negative lens (7) and the receiving lens (12), and between the transmitting lens (
11) and the receiving lens (12) are parallel systems, which has the following advantages.

First, in general, regarding transmission optical systems, assuming that the size of the light source is constant, the shorter the focal length of the transmission optical system as a whole, the larger the transmission angle, which widens the allowable range for distance measurement. However, in the configuration of the present invention, by changing the focal length of the transmitting lens (11), it is possible to shorten the focal length of the transmitting optical system as a whole without significantly changing the total length of the transmitting optical system. , there is a high degree of freedom in designing the basic configuration.Secondly, since the ranging light is infrared light, it is necessary to remove the background light cant filter (14) when adjusting the ranging optical system. , because a background light cut filter is placed in the parallel light beam,
There is no focus shift or optical axis shift due to the insertion and removal of this filter, and it is possible to perform sufficient adjustment for infrared light through visible light observation. Moreover, since the light beam incident on the background light cut filter is neither convergent nor diverging, there is no risk of being adversely affected by the angular characteristics of the multilayer thin film forming this filter. Thirdly, since the optical path of the reference optical system is shared by a part of the transmitting optical system and a part of the receiving optical system, the structure is simple and does not require a dedicated member as the reference optical system. Since the light source (10) and the light receiving member (13) are arranged on the same optical axis, adjustment can be made extremely easily and accurately.

If the light source and the light receiving member are arranged on the same straight line, and also on the same plane as the plane containing the optical axis of the reference optical system, the reference optical system and the distance measuring optical system can be integrated. Even if the reference telescope is configured in a vertical direction, the width of the reference telescope barrel will not be increased, and the same restrictions apply to configuring the reference telescope to be rotatable in the vertical plane relative to the main body of the device, similar to the general Odoride. No.

In the above embodiment, the light source was transmitted and the light receiving member was placed at the focal position of the lens (11), and the light receiving member was placed at the focal position of the receiving lens (12), but the light source and the light receiving member could not be placed directly at each focal position. Needless to say, it is possible to configure the optical fiber to guide each light beam without using an optical fiber.

(Effects of the Invention) As described above, according to the present invention, the important elements of the distance measuring optical system, such as the light source, the light receiving member, the transmitted light reflecting member, and the received light reflecting member, are integrated on the parallel optical path by the auxiliary lens. Since these element groups are arranged in parallel, it is possible to separate and independently assemble and adjust these element groups using the parallel light beam as a boundary. After that, these important elements can be attached to the main body, which has a reference optical system including an objective lens, focusing lens, etc., an optical path splitter, and an auxiliary lens, which have been assembled separately. It is possible to easily assemble and adjust each member with high precision. Moreover, since there is no need to provide a dedicated member such as a reference light optical path for light wave distance measurement, the entire apparatus can be made compact without complicating the structure.

[Brief explanation of the drawing]

FIG. 1 is an optical path diagram showing the configuration of an embodiment of a light wave distance measuring device according to the present invention, and FIGS. 2 (A) and (B) are a side view and a plan view of a light shielding plate provided in the distance measuring optical system. . [Explanation of symbols of main parts] 1... Objective lens 2... Focusing lens 5... Eyepiece lens 6... Optical path splitter 7... Negative lens 8...
- Transmitted light reflecting member 9... Received light reflecting member 10...
Light source 11... Transmission lens 12... Receiving lens 13
... Light-receiving material applicant Takashi Watanabe, agent of Nippon Kogaku Kogyo Co., Ltd.

Claims (1)

[Claims] It has a reference optical system in which an objective lens, a focusing lens, and an eyepiece are arranged in sequence, and an optical path splitter is arranged between the objective lens and the focusing lens, and an optical path split by the optical path splitter is a transmitted light reflecting section +4 and a received light reflecting member which are integrally arranged on the optical axis of the objective lens, and a light source that supplies transmitted light to the transmitted light reflecting member and receives a luminous flux from the received light reflecting member. In the coaxial light wave ranging device having a light receiving member, an auxiliary lens is disposed between the optical path splitter and the integrally arranged transmitting light reflecting member and receiving light reflecting member. : A light wave ranging device characterized in that an afocal system is formed by the J objective lens and the auxiliary lens, and the reflecting surfaces of the transmitted light reflecting member and the received light reflecting member are orthogonal to each other. .