In mechanical optical comparators small displacements of the measuring plunger are amplified starting by a system consisting of pivoted levers. The amplified mechanical movement is further by an easy optical system involving the projection of a picture.
The usual arrangement employed in such the system causes a plane reflector to till about an axis and therefore the image of an index is projected on a scale on the inner surface of a ground glass screen.
Optical magnification system provides high degree of measuring precision due to reduction of moving members and better wear resistance qualities. The optical magnification is also free from bending, friction, wear etc…
Advantages of optical comparator
- Optical comparators are capable of giving a high degree of measuring precision due to high magnification and therefore the reduction of moving members to minimum.
- Further these posses better wear resistance qualities, as the only wearing members are the plunger and its guide and the mirror pivot bearing.
- The optical comparators are that provision of an illuminated scale enables readings to be taken without regard to the room lighting conditions.
- The point of importance in Mechanical comparator is that the mirror used must be of front reflection type there are two reflected images, one each from front and back.
- Thus the reflected image is not well defined one as one bright and other blurred images are observed.