US 11,754,679 B2
Electro-optical distance meter
Nobuyuki Nishita, Tokyo (JP); Takashi Takahashi, Tokyo (JP); Tatsuya Kojima, Tokyo (JP); and Saki Horita, Tokyo (JP)
Assigned to TOPCON CORPORATION, Tokyo (JP)
Filed by TOPCON CORPORATION, Tokyo (JP)
Filed on Mar. 26, 2019, as Appl. No. 16/365,523.
Claims priority of application No. 2018-061906 (JP), filed on Mar. 28, 2018.
Prior Publication US 2019/0302233 A1, Oct. 3, 2019
Int. Cl. G01S 7/48 (2006.01); G01S 7/481 (2006.01); G02B 26/00 (2006.01); G01S 17/10 (2020.01)
CPC G01S 7/4814 (2013.01) [G01S 17/10 (2013.01); G02B 26/005 (2013.01)] 5 Claims
OG exemplary drawing
 
1. An electro-optical distance meter comprising:
a light source configured to emit light for distance measurement;
a detector configured to receive the light and generate a distance measurement signal;
an external optical path configured to guide the light from the light source to a target as measurement light;
an internal optical path configured to guide the light from the light source directly to the detector as reference light in the same direction as the external optical path;
a calculator configured to determine a distance from the distance measurement signal, and configured to transmit a switching signal for switching between the external optical path and the internal optical path; and
a plate-like liquid shutter configured to select, based on the switching signal, one of the external optical path or the internal optical path as the optical path through which the light from the light source travels, by switching a region of light-blocking liquid,
wherein the plate-like liquid shutter is disposed such that one region of the plate-like liquid shutter is located across the external optical path and one other region of the plate-like liquid shutter is located across the internal optical path, the plate-like liquid shutter being comprised of a single electrowetting device capable of switching the region of the light-blocking liquid between the one region and the one other region of the plate-like liquid shutter in response to application of voltage.