Electro-optical distance meter
AssigneeOptec Co., Ltd.
InventorYoshinori Narutaki
Life of this patent
Estimating the term…
Abstract
An electro-optical distance meter has a light-emitting element that is directed through a shutter to a target and returned from the target to a photodetector. Internal and external optical paths are continuously switched by the shutter with a predetermined time ratio. The internal optical path is used for calibrating the distance being measured. The meter reduces the measurement time and enhances accuracy. In one form, the shutter comprises a disc having a C-shaped opening with an index thereon for providing a reference signal. In another form, the shutter comprises a liquid crystal switch.
Claims11
An electro-optical distance meter for measuring an external optical path comprising:
- a light-emitting element for emitting modulated light to a target;
- a lens in optical alignment with said light-emitting element and said target providing an external optical path;
- a photo-detector element in optical alignment with said target for receiving return light from said target through another lens for providing an external return optical path;
- an internal optical path having a predetermined length and being used for calibrating said external optical path to be measured;
- a continuously rotating shutter disposed in said external and internal optical paths for switching between said external and internal optical paths, said shutter comprising a rotating disc having a C-shaped opening and an index corresponding to a leading angular position of said C-shaped opening;
- a dichroic means disposed in alignment with said shutter having a predetermined inclined angle to the axis of said light-emitting element;
- a stationary means for detecting said index of said rotating disc;
- and
- an electric control means operatively connected to said light-emitting and photo-detector elements and stationary means for performing measurements of said external and internal optical paths in a predetermined time ratio.
An electro-optical distance meter for measuring an external optical path comprising:
- a light-emitting element for emitting modulated light to a target;
- a lens in optical alignment with said light-emitting element and said target providing an external optical path;
- a photo-detector element in optical alignment with said target for receiving return light from said target through another lens for providing an external return optical path;
- an internal optical path having a predetermined length and being used for calibrating said external optical path to be measured;
- a first stationary shutter disposed between said light-emitting element and said lens for switching said external optical path by an electric potential means;
- a dichroic means disposed in optical alignment with said first shutter having a predetermined inclined angle to the axis of said light-emitting element;
- a reflector in optical alignment with said dichroic means in said internal optical path;
- a second stationary shutter disposed between said dichroic means and said reflector in optical alignment in said internal optical path for switching said internal optical path by another electric potential means;
- and
- an electric control means operatively connected to said light-emitting and photo-detector elements and first and second stationary shutters for performing measurements of said external and internal optical paths in a predetermined time ratio.
Dependencies are inferred from the claim text.