| 摘要 |
The present invention relates to a device for facilitating the focusing of a distance meter in which the object is accurately imaged by a lens, and the distance sought is determined by measuring the lens-to-image distance. A screen is used to screen the central rays so that only the edge rays are used for imaging. In addition, a luminous mark is placed on the side of a beam and the image of said mark is refracted into the beam by a reflector and projected on the object by the lens. The reflector is a prism which is located in the screened section of the beam, between the imaging lens and the image of the object. This arrangement is suitable for use when the object to be measured is located in a rock chamber, or the like, in which case it is essential that the object be illuminated.
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