Alternating opaque and clear quadrants meet at a defined centre. The intersecting boundaries provide horizontal and vertical edge references.
Specify optical glass or fused silica, overall dimensions, thickness, pattern-side orientation and the clear aperture. Define transmission, reflectance or optical density at the working wavelength when optical contrast is critical.
Four sectors help an operator distinguish left/right and up/down displacement during centring. Sector symmetry and the centre opening affect how a target can be compared with the reference.
Optical references in measuring instrumentsThe glass supplies visible boundaries. A quadrant photodiode instead measures light in four sensing areas and produces electrical signals; the two parts have different functions even when their layouts look similar.
Position the pattern at the intended focal planeAlternating opaque and clear quadrants meet at a defined centre. The intersecting boundaries provide horizontal and vertical edge references.
Use alternating quadrants for centring and directional alignment where a sharp contrast transition around the common intersection is useful.
A quadrant reticle divides the optical field into directional reference sectors. It supplies visible geometry; a quadrant photodetector supplies electrical measurements from separate sensing areas.
Line width, centre opening, axis length, orientation marks and mounting diameter can be matched to the visible field.
A patterned glass reference component with the selected graduations, outline and mounting dimensions, accompanied by the specified inspection records.
Orthogonal contrast boundaries for centre and orientation checks.
Quadrant alignment reticles divide the field around a centre to support position, axis and offset assessment.
Define quadrant boundaries and the central reference for the optical task; relate them to the mounting datum.
Quadrant layout, centre, gaps, line width, active field, film side and outline.
A crosshair gives centre and direction. Quadrant structures also distinguish regions, helping judge which way a target is displaced.