JPS5921514B2 - Optical system of light wave distance meter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical system for a light wave distance meter that is capable of coaxial reference (simultaneous reference).

Conventional optical rangefinders transmit and receive light through separate objective lenses, which has the disadvantages of large size and complicated operation, and improvements are desired. Ta.

Therefore, the main object of the present invention is to provide a coaxial standard optical distance meter capable of transmitting and receiving light for distance measurement through one objective lens, and to provide a coaxial reference optical distance meter that can perform both light transmission and reception for distance measurement through a single objective lens, and also to improve the optical path length and electric circuit within the optical distance meter device. An object of the present invention is to provide an optical system for a light wave distance meter that enables calibration to eliminate distance measurement errors based on phase changes. The present invention will be explained below using embodiments shown in the drawings.

FIG. 1 is an optical path diagram of an example of the optical system of the optical distance meter of the present invention, and this optical system includes a dichroic mirror 2 behind an objective lens 1, and a focusing lens movable in the optical axis direction, i.e. A reference optical system is formed by arranging a lens 4, a focusing plate 5 used on the imaging plane of this telescope system, and an eyepiece 6.

The dichroic mirror 2 allows the reference light beam to pass through the rear side as it is, but reflects the light wave received by the distance measuring light receiving optical system upward at a right angle. Although this dichroic mirror itself is already known, it is not shown in the figure. In this embodiment, the slopes of a pair of right-angled prisms are brought into contact with each other, and a dichroic surface 2' is formed between the slopes, and the dichroic surface 2' reflects light having a wavelength within a certain range. Light of other wavelengths has the property of being transmitted. The reflecting surface of the dichroic mirror 2 in the present invention passes through the eyepiece lens 1 in the light-receiving optical system for distance measurement, which will be described later.
It is formed so that only the wavelengths of the received light waves that fall on it are reflected, and the light waves of other wavelengths are transmitted. On the left or right side of the upper surface 2a of the dichroic mirror 2 (at a position deviated from the optical path reference of the incident light), there is a right-angled prism 3 having a width (l) smaller than the width (l) of the dichroic mirror 2.
Place. For example, as shown in FIG. 2, a right-angled prism 3 with a width (f) approximately half the width (l) of the dichroic mirror 2 is placed on the left half of the upper surface of the dichroic mirror 2.
are glued and fixed, and an afocal lens 7 and a light transmitting element (for example, a light transmitting diode) 10 are arranged behind the right angle prism 3, and the light transmitting element 10, the afocal lens 7, the right angle prism 3, and the dichroic The mirror 2 and the objective lens 1 form a light transmitting optical system for distance measurement. The distance-measuring light-receiving optical system includes a light-receiving element 11 disposed above the surface 2b opened by the deflection of the right-angle prism 3 and at the focal length of the objective lens 1. The pickup mirror 2 and the light receiving element 11 form a distance measuring light receiving optical system.

Although FIGS. 1 and 2 show a dichroic mirror 2 that bends the distance measuring light wave upward, a dichroic mirror 2 that bends the light wave downward instead of upward is used, and Of course, it is also possible to change the positions of the distance measuring light transmitting optical system and the distance measuring light receiving optical system as appropriate. It is also possible to switch the positions of the light transmitting element and the light receiving element. A calibration optical system is formed between the distance measuring light transmitting optical system and the distance measuring light receiving optical system.

That is, in the specific example shown in FIG. A rectangular prism 12 is arranged to form a calibration optical system. The calibration optical path of the calibration optical system is an optical path from the light transmitting element 10 to the light receiving element 11 via the prism 9 and the prism 12. However, the prism 12 should be placed at a position where it does not block the reflected light receiving optical path of the ranging light receiving optical system from the objective lens 1 to the light receiving element 11, for example, at a position outside the light receiving optical path. Further, the prism frame of the prism 9 is provided with a rotating shaft 8, and the rotating shaft 8 is fixed to the main body of the light wave distance meter (not shown). In the present invention, a target is determined in a reference optical system consisting of an eyepiece lens 6, an afocal lens 4, a dichroic mirror 2, and an objective lens 1.

A light wave for distance measurement emitted from the light transmitting element 10 is emitted from the objective lens 1 to the corner prism via the afocal lens 7, the right angle prism 3, and the dichroic mirror 2. The reflected light wave reflected from the corner prism is bent at a right angle by the dichroic mirror 2 via the objective lens 1, and is passed through the area where the right angle prism 3 is not present, that is, the open surface 2b of the dichroic mirror 2, and is passed through the light receiving element, e.g., the light receiving diode 10. to form an image. Therefore, in order to eliminate distance measurement errors due to phase changes in the optical path length in the optical system of a light wave distance meter and phase changes in the electric circuit, it is necessary to use a calibration optical system to detect errors due to phase changes. Fix it.

That is, during distance measurement, the two-sided reflective prism 9 of the calibration optical system is rotated about the rotation axis 8, and is moved and rotated to a position where it does not block the transmitting light wave of the distance measuring light transmitting optical system. At the time of calibration, the two-sided reflective prism 9 is rotated to a position where the light transmission light wave is blocked, that is, a position where a calibration optical path is formed. The light transmission light wave emitted from the light transmission element 10 is 2
The light is reflected at a right angle by the first reflecting surface 9aVC} of the surface reflecting prism 9, further reflected toward the right-angle prism 12 by the second reflecting surface 9b, and reflected toward the light-receiving element 11 via the right-angle prism 12, thereby forming a calibration optical path. Both the light wave received by the light receiving element 11 of the distance measuring light receiving optical system and the calibration light wave are compared to detect a phase shift. As described above, the present invention combines both the light waves of the light transmitting optical system for distance measurement and the light receiving optical system for distance measurement into one.
It is possible to measure distance using a coaxial standard like two objective lenses, and it is also possible to calibrate to eliminate distance measurement errors due to phase changes in the optical path length within the optical distance meter device and phase changes in the electric circuit. This has the effect of making it possible to obtain a light wave distance meter optical meter.

[Brief explanation of the drawing]

FIG. 1 is an optical path diagram showing one embodiment of the optical system of a light wave distance meter according to the present invention, and FIG. 2 is an enlarged perspective view of the dichroic mirror shown in FIG. 1. 1... Objective lens, 2... Dichroic mirror,
2a... Surface in the refraction direction of the distance measuring light wave in the dichroic mirror, 2b... Opening surface, 3... Right angle prism, 4... Focusing lens (non-focal lens), 5... Focal point Plate, 6... Eyepiece, 7... Afocal lens, 8.
... Rotation axis of the prism frame, 9... Calibration prism, q
... Frame body, 10... Light transmitting element, 11... Light receiving element, 12... Right angle prism.

Claims (1)

[Claims] 1. Behind the objective lens 1, a dichroic mirror 2, a focusing lens 4, a focusing plate 5, and an eyepiece lens 6 are arranged to transmit the reference beam as it is to the rear and reflect the distance measuring light wave at right angles. A reference optical system is formed, and a rectangular prism 3 having a width smaller than the dichroic mirror 2 is fixed to one side of the surface 2a located in the right angle reflection direction of the received light wave for distance measurement in the dichroic mirror 2. Afocal lens 7 and light transmitting element 1 are placed behind the right angle prism.
A light transmitting optical system for distance measurement is formed by a light transmitting element 10, an afocal lens 7, a right angle prism 3, a dichroic mirror 2, and an objective lens 1. A light-receiving element 11 is arranged above the open surface 2b formed by the deviation of the object lens 1 and at the focal length of the objective lens 1, and the objective lens 1, dichroic mirror 2, and light-receiving element 11 form a light-receiving optical system for distance measurement. A two-sided reflective prism 9 is rotatably installed between the afocal lens 7 and the light transmitting element 10, and a two-sided reflective prism 9 is rotatably installed between the two-sided reflective prism and the light receiving element 11 so that the light receiving optical system is not blocked. the second reflective surface 9 of the two-sided reflective prism 9.
An optical system for a light wave rangefinder, characterized in that a right-angle prism 12 is disposed at a position corresponding to b, and a calibration optical system is formed by a light transmitting element 10, a dihedral reflection prism 9, and a right-angle prism 12.