US 6,549,874 B2Granted

Distance measuring device

AssigneeSeiko Precision Inc.

InventorsHiroyuki Saito, Kenji Hyakutake

Life of this patent

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Abstract

A distance measuring device is provided with regulating circuit for removing offset voltages. Before conducting distance measurement, the regulating circuit outputs a reference voltage on the basis of offset voltages of an amplifier and an integrating circuit used to amplify and integrated reflected light from an object. The regulating circuit comprises a D/A converter for outputting an analog voltage. A value representing the offset voltages is stored and, at the time of distance measurement, the reference voltage is set based on the stored value. The integrating circuit integrates two outputs of the amplifier based on near-side and far-side light receiving means, and uses a calculating device to find a distance to the object based on the integrated output voltages of the integrating circuit.

Claims20

Dependent claims

A distance measuring device comprising:

light projecting means for irradiating light onto an object undergoing distance measurement;
light receiving means for receiving light irradiated by the light projecting means and reflected by the object generating two outputs that vary in value depending upon a position of received light;
an amplifier for separately amplifying the two outputs of the light receiving means on the basis of a reference voltage;
a regulating circuit for regulating the reference voltage so that the reference voltage has a desired value;
an integrating circuit for integrating outputs of the amplifier and producing an integrated outputs;
and calculating means for calculating a distance to the object undergoing distance measurement based on integrated outputs of the integrating circuit corresponding to the two outputs of the light receiving means;
wherein the regulating circuit regulates the reference voltage on the basis of offset voltages of the amplifier and of the integrating circuit, so that an output of the amplifier reduces effects of the offset voltages on the calculated distance.

4 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/772,013Filed 29 Jan 2001
Priority: JP 2000-01990628 Jan 2000
Published: US 2002/0032543 A114 Mar 2002
Granted: 15 Apr 2003
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G01S 17/46
Systems determining position data of a target: indirect determination of position data
G01S 7/4861
Receivers: circuits for detection, sampling, integration or read-out
G01S 17/88
Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems: lidar systems specially adapted…
G01S
Radio direction-finding