US 9,638,799 B2 · Scan mirrors for laser radar

Abstract

Laser radar systems include a pentaprism configured to scan a measurement beam with respect to a target surface. A focusing optical assembly includes a corner cube that is used to adjust measurement beam focus. Target distance is estimated based on heterodyne frequencies between a return beam and a local oscillator beam. The local oscillator beam is configured to propagate to and from the focusing optical assembly before mixing with the return beam. In some examples, heterodyne frequencies are calibrated with respect to target distance using a Fabry-Perot interferometer having mirrors fixed to a lithium aluminosilicate glass-ceramic tube.

Claims43

Dependent claims

A beam pointing system, comprising:

a first rotational stage configured to provide a rotation about a first axis;
a second rotational stage coupled to the first rotational stage, and configured to provide a rotation about a second axis that is not parallel to the first axis;
a rotatable optical element coupled to the second rotational stage;
an optical system situated to provide a probe beam to the rotatable optical element;
and
a stationary optical system configured to be stationary with respect to rotations of the first rotational stage and the second rotational stage, wherein the stationary optical system includes a laser source configured to produce the probe beam and deliver the probe beam to the optical system situated to provide the probe beam to the rotatable optical element.

3 more elements

A beam pointing system, comprising:

a first rotational stage configured to provide a rotation about a first axis;
a second rotational stage coupled to the first rotational stage, and configured to provide a rotation about a second axis that is not parallel to the first axis, wherein the first rotational stage and the second rotational stage include respective encoders;
a rotatable optical element coupled to the second rotational stage, wherein the rotatable optical element is situated to receive the probe beam from the optical system along a propagation axis parallel to the second axis;
an optical system configured so as to be stationary with respect to rotations of the first and second rotational stages and situated to provide a probe beam to the rotatable optical element, the optical system including a photodetector configured to receive a portion of the probe beam returned from a target, wherein the rotatable optical element is situated to receive the probe beam from the optical system along an axis parallel to the first axis, the optical system further including a corner cube that is translatable to adjust a focus distance of the probe beam and an objective lens, wherein the corner cube is situated so as to vary a propagation distance associated with the objective lens;
a camera secured so as to be rotatable about the first axis so as to image a target field of view;
and
a signal processor coupled to the encoders and configured to determine a pointing direction of the probe beam based on encoder signals.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application

13/840,658Filed 15 Mar 2013 · us provisional application

Priority

21 Nov 2012

Published

US 2015/0355327 A110 Dec 2015

Granted

2 May 2017

Term ends

Not estimatedThe source records don’t support an estimate.

Classification13 codes

G01S 17/26
Using transmission of interrupted, pulse-modulated waves: wherein the transmitted pulses use a frequency-modulated or phase-modulated carrier…
G01S 7/4812
Common to transmitter and receiver: transmitted and received beams following a coaxial path
G01S 7/4817
Constructional features, e.g. arrangements of optical elements: relating to scanning
G01S 7/4818
Constructional features, e.g. arrangements of optical elements: using optical fibres

Scan mirrors for laser radar

Life of this patent

Scan mirrors for laser radar

Life of this patent

Abstract

Claims43