Oblique illuminator for inspecting manufactured substrates

摘要

One embodiment relates to an oblique illuminator. The oblique illuminator includes a light source emitting a light beam, a first reflective surface, and a second reflective surface. The first reflective surface has a convex cylindrical shape with a projected parabolic profile along the non-powered direction which is configured to reflect the light beam from the light source and which defines a focal line. The second reflective surface has a concave cylindrical shape with a projected elliptical profile which is configured to reflect the light beam from the first reflective surface and which defines first and second focal lines. The focal line of the first reflective surface is coincident with the first focal line of the second reflective surface. The first and second focal lines of the second reflective surface may be a same line in which case the elliptical curvature is a projected spherical profile. Other embodiments, aspects and features are also disclosed.

主权项

1. An oblique illuminator comprising:
a light source emitting a light beam; a first reflective surface having a convex cylindrical shape with a projected parabolic profile which is configured to reflect the light beam from the light source and which defines a focal line; and a second reflective surface having a concave cylindrical shape with a projected elliptical profile which is configured to reflect the light beam from the first reflective surface and which defines first and second focal lines, wherein the focal line of the first reflective surface is coincident with the first focal line of the second reflective surface, wherein the projected elliptical profile of the second reflective surface is configured such that the second focal line of the second reflective surface lies on a surface of a target substrate, and wherein the light beam reflected from the second reflective surface impinges on the target surface at an oblique angle.