US 5,461,417 A · Continuous diffuse illumination method and apparatus

Abstract

The invention pertains to a method and apparatus for providing a continuous, uniform, diffuse lighting environment for use in conjunction with electronic machine vision, or manual microscope inspection systems to inspect specular surfaces such as soldered circuits, ball bearings, reflective packaging, relective packaging, etc. The disclosed invention effectively eliminates apparent variations in surface brightness caused by the reflection of discontinuities in traditional machine vision lighting systems that typically require windows or viewing openings or orifices to allow visual access to the object being observed, thus allowing for a true observation signal from which the effect of surface geometry has been substantially removed. The object being observed is illuminated using a diffuse lighting system that comprises, in combination, an on-observation axis diffuse light source and an off-observation axis light source each controlled under separate brightness control such that a substantially uniform diffuse lighting environment is created over the entire object.

Claims32

Dependent claims

A diffuse lighting device for uniformly illuminating a desired portion of an object (10, 72) when observed along an observing axis extending through an object observing location, said diffuse lighting device comprising:

a surface, for supplying light, defining an opening (20, 48, 50, 52, 68, 103) through which the observing axis (A, 70) passes, said surface being arranged to supply primary diffused light (22, 54, 96, 101, 113, 127, 143) to provide said uniform illumination of the desired portion of the object (10, 72), when placed at the observing location and viewed along said observing axis, except for a portion of the object (10, 72) effected by the opening;
a source (34, 78) for producing secondary diffused light to illuminate the desired portion of the object effected by the opening;
and
a partially reflective mirror (14, 74, 129) for supplying said secondary diffused light (34 78) along the observing axis (A, 70) to uniformly illuminate each portion of the object (10, 72) effected by the opening to produce, when primary diffused light illuminates said surface, said uniform illumination of the desired portion of the object (10, 72) when viewed along the observing axis.

1 more element

A method of uniformly illuminating a desired portion of an object (10, 72) when observed along an observing axis extending through an object observing location, said method comprising the steps of:

defining an opening (20, 48, 50, 52, 68, 103) within a surface, for supplying light, through which the observing axis (A, 70) passes;
arranging said surface to supply primary diffused light (22, 54, 96, 101, 113, 127, 143) to provide said uniform illumination of the object (10, 72) when placed at the observing location and viewed along said observing axis, except for a portion of the object (10, 72) effected by the opening;
providing a source of secondary diffused light to illuminate the desired portion of the object;
and
supplying said second diffused light, via a partially reflective mirror (14, 74, 129), along the observing axis (A, 70) to uniformly illuminate the portion of the object (10, 72) effected by the opening to produce, when primary diffused light illuminates said surface, said uniform illumination of the desired portion of the object (10, 72) when viewed along the observing axis.

2 more elements

A method of uniformly illuminating a desired portion of the object for observation along an observing axis extending through an object observing location, said method comprising the steps of:

defining an opening, through which the observing axis (A, 70) passes, in a surface;
placing the desired portion of the object at the observing location;
illuminating said surface to illuminate the desired portion of the object with primary diffused light to provide uniform illumination of the object, except for a portion of the desired portion of the object effected by the opening, when viewed along the observing axis;
illuminating a diffuser to indirectly illuminate the desired portion of the object with secondary diffused light supplied along the observing axis to illuminate uniformly the portion of the object effected by the opening, when viewed along the observing axis;
and
viewing the desired portion of the object along the observing axis with an observation device.

3 more elements

Dependencies are inferred from the claim text.

Continuous diffuse illumination method and apparatus

Life of this patent

Continuous diffuse illumination method and apparatus

Life of this patent

Abstract

Claims32