Optical device and optical measurement method

An optical device comprising:

• a monochromatic light source;
• a light distribution switching portion configured to reflect monochromatic light emitted from the monochromatic light source in one fan-shaped region among a plurality of fan-shaped regions centered on a central optical axis and transmit the monochromatic light in other fan-shaped regions of the plurality of fan-shaped regions;
• an objective lens configured to condense the light reflected the light distribution switching portion onto an object;
• an aperture stop configured to collect reflected light from the object;
• an imaging lens configured to condense the reflected light from the object, the reflected light having passed through the aperture stop;
• a light receiver on an imaging plane formed by the imaging lens and configured to receive the reflected light from the object and photoelectrically convert the received reflected light;
• and
• a controller configured to instruct the light distribution switching portion to change a region reflecting light over time, and calculate a normal direction of the object based on an electrical signal photoelectrically converted by the light receiver.

An optical device comprising:

• a monochromatic light source;
• a light distribution switching portion configured to transmit monochromatic light emitted from the monochromatic light source in one fan-shaped region among a plurality of fan-shaped regions centered on a central optical axis and block the monochromatic light in other fan-shaped regions of the plurality of fan-shaped regions;
• an objective lens configured to condense the light passing through the light distribution switching portion onto an object;
• an aperture stop configured to collect reflected light from the object;
• an imaging lens configured to condense the reflected light from the object, the reflected light having passed through the aperture stop;
• a half mirror between the objective lens and the imaging lens;
• a light receiver on an imaging plane formed by the imaging lens and configured to receive the reflected light from the object and photoelectrically convert the received reflected light;
• and
• a controller configured to instruct the light distribution switching portion to change a region transmitting light over time, and calculate a normal direction of the object based on an electrical signal photoelectrically converted by the light receiver,
• wherein the half mirror reflects the monochromatic light arriving from the light distribution switching portion in the direction of the objective lens, and transmits the reflected light arriving from the objective lens in the direction of the aperture stop,
• wherein the monochromatic light source is a plurality of monochromatic light sources,
• wherein the light distribution switching portion is further configured to transmit the monochromatic light emitted from the monochromatic light source in the one of the plurality of fan-shaped regions centered on the central optical axis, block light in the other fan-shaped regions of the plurality of fan-shaped regions, and change the fan-shaped region transmitting the monochromatic light over time,
• wherein the controller is further configured to control the light distribution switching portion in which the region transmitting the light is changed over time, control one of the plurality of monochromatic light sources to emit light and simultaneously control other monochromatic light sources not to emit light, and change the monochromatic light source emitting the light over time,
• wherein the controller is further configured to, based on inspecting the object having a plurality of regions having different spectral reflectance characteristics, divide an image captured by the light receiver into a plurality of regions according to arrangement information of the regions, set at least one of an exposure time, a gain, an illumination light amount, and an illumination wavelength of the light receiver so as to suppress a difference in inspection precision caused by the spectral reflectance characteristics based on the spectral reflectance characteristics for each of the plurality of regions, perform calculation of a normal angle and restoration of a three-dimensional shape only in a specific region among the plurality of regions, obtain a three-dimensional shape of an entire field of view by interpolating another region among the plurality of regions by a three-dimensional shape around the region, and inspect flatness.