US 7,253,910 B2 · Optical measuring device

Abstract

An optical measuring device capable of improving the precision of detection of contamination on a protective glass is disclosed. With threshold values as large as 90%, 50%, 10% of a peak value of a scan signal, measured values Q90, Q50, Q10 of a dimension of a work to be measured are derived, respectively. It is determined whether a difference between the measured value Q90 and the measured value Q50 (or a variation of the measured value) is equal to or larger than a predetermined reference value. (B)-(D) show the presence of contamination on the protective glass, equal to or larger than the reference value. (A) shows the absence of contamination, lower than the reference value. It is then determined whether a difference between the measured value Q50 and the measured value Q10 is equal to or larger than a predetermined reference value. (D) shows the presence of thick contamination on the protective glass, equal to or larger than this reference value. Accordingly, a buzzer is driven and a red lamp is turned on to give the alarm to the operator to remove the contamination immediately.

Claims13

Dependent claims

An optical measuring device, comprising:

a projector means operative to use a collimated beam derived from a beam emitted from a light-emitting element to repeatedly scan a scan region in which a work to be measured locates;
a photoreceptor element operative to receive a beam transmitted through said scan region to provide a scanned signal;
a binarized signal generator means configured to binarize said scanned signal with a plurality of different threshold values to generate a plurality of binarized signals;
an arithmetic means operative to calculate on the basis of said binarized signals a measured value associated with said work to be measured;
a decision means operative to compare a plurality of measured values calculated at said arithmetic means on the basis of said binarized signals to determine whether an abnormality arises on an optical path of said beam from said light-emitting element to said photoreceptor element;
and
a notice means operative to notice said abnormality if said decision means determines that said abnormality arises.

4 more elements

An abnormality detecting method operative to detect an abnormality in an optical measuring device, said optical measuring device comprising:

a projector means operative to use a collimated beam derived from a beam emitted from a light-emitting element to repeatedly scan a scan region in which a work to be measured locates;
a photoreceptor element operative to receive a beam transmitted through said scan region to provide a scanned signal;
a binarized signal generator means configured to binarize said scanned signal to generate a binarized signal;
and
an arithmetic means operative to calculate on the basis of said binarized signal a measured value associated with said work to be measured,
said method comprising:
a binarized signal generating step generating in said binarized signal generator means a plurality of binarized signals using a plurality of threshold values,
a decision step comparing a plurality of measured values calculated on the basis of each of a plurality of said binarized signals to determine whether an abnormality arises on an optical path of said beam from said light-emitting element to said photoreceptor element;
and
a notice step noticing said abnormality by outputting a notice signal indicating that said abnormality arises.

7 more elements

Dependencies are inferred from the claim text.

Optical measuring device

Life of this patent

Optical measuring device

Life of this patent

Abstract

Claims13