Optical inspection method and apparatus
First Claim
1. A method for inspecting an object having upper and lower faces for detecting defects existing on the object, the method comprising:
- a) providing first and second beams of radiation;
b) directing the first beam of radiation onto the object so as to illuminate a first area of the object, and sensing a light component reflected from one face of the object;
c) directing the second beam of radiation onto the object so as to illuminate a second, different area of the object, and sensing a light component transmitted through the upper and lower faces of the object;
d) simultaneously acquiring first and second images of the object, wherein the first image is formed by the reflected light component and the second image is formed by the transmitted light component; and
e) analyzing said first and second images so as to provide data indicative of said defects.
2 Assignments
0 Petitions
Accused Products
Abstract
A method and an apparatus for an optical inspection of an object, having upper and lower faces, so as to detect defects existing on the object. First and second beams of an incident radiation are produced and directed onto the object. A light component of the first incident beam, which is reflected from one face of the object, and a light component of the second incident beam, which is transmitted through the upper and lower faces of the object, are simultaneously sensed. First and second images, formed, respectively by reflected and transmitted light components are acquired and analyzed so as to provide data indicative of the defects.
173 Citations
55 Claims
-
1. A method for inspecting an object having upper and lower faces for detecting defects existing on the object, the method comprising:
-
a) providing first and second beams of radiation;
b) directing the first beam of radiation onto the object so as to illuminate a first area of the object, and sensing a light component reflected from one face of the object;
c) directing the second beam of radiation onto the object so as to illuminate a second, different area of the object, and sensing a light component transmitted through the upper and lower faces of the object;
d) simultaneously acquiring first and second images of the object, wherein the first image is formed by the reflected light component and the second image is formed by the transmitted light component; and
e) analyzing said first and second images so as to provide data indicative of said defects. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 24, 25, 26, 27)
directing the reflected and transmitted light components via an optical system mounted in optical paths of the reflected and transmitted light components onto the first and second image sensors accommodated at one side of the object.
-
-
4. The method according to claim 1, wherein directing the first and second beams of the radiation onto the object further comprise manipulating said first and second beams of the radiation to illuminate first and second parallel spaced-apart corresponding portions of the object.
-
5. The method according to claim 4, wherein each of said first and second portions of the object are in the form of a strip.
-
6. The method according to claim 4, wherein
the first and second beams of the radiation are directed onto the object from the opposite faces thereof; -
the reflected and transmitted light components are directed onto, respectively, first and second image sensors, accommodated at one side of the object, via an optical system mounted in optical paths of the reflected and transmitted light components; and
the first and second portions extend symmetrically relative to an optical axis of said optical system.
-
-
7. The method according to claim 1, wherein
the first and second beams of the radiation are directed onto the object from the opposite faces thereof; - and
the first and second beams of the incident radiation are formed of light having different wavelengths.
- and
-
8. The method according to claim 1, wherein
the first and second beams of the radiation are directed onto the object from the opposite faces thereof; the first and second beams of the radiation are formed of light having different polarizations.
-
9. The method according to claim 4, wherein the first and second images of the first and second portions are in the form of two lines, each having a width “
- a” and
a length “
b”
, the width “
a”
being substantially smaller than the width of the respective portion, a space “
d”
between lines being such as to satisfy the following condition;
- a” and
-
10. The method according to claim 1, wherein the step of providing the first and second beams of the radiation comprises providing first and second light sources each generating a beam of light.
-
11. The method according to claim 1, wherein the step of providing the first and second beams of the radiation comprises providing a light source generating a beam of light and directing the generated beam of light towards the object via a beam splitter, which splits the generated beam of light into the first and second beams of the radiation.
-
12. The method according to claim 1, further comprising the step of:
supporting the object for sliding movement along two orthgonally oriented axes within an inspection plane so as to provide said first and second images of each point of the object.
-
13. The method according to claim 1, wherein the analyzing of the first and second images comprises comparing the images to each other.
-
24. The method according to claim 1, wherein simultaneously acquiring first and second images of the object comprises directing the reflected light component to a first sensor located on a first side of the object and directing the transmitted light component to a second sensor located on said first side of the object.
-
25. The method according to claim 1, wherein simultaneously acquiring first and second images of the object comprises directing the reflected light component to a first multi-element sensor and directing the transmitted light component to a second multi-element sensor.
-
26. The method according to claim 25, wherein said first multi-element sensor is a first charge coupled device (CCD) having a plurality of pixels, and said second multi-element sensor is a second charge coupled device (CCD) having a plurality of pixels.
-
27. The method according to claim 25, wherein said first multi-element sensor is a first time delay integration (TDI) sensor, and said second multi-element sensor is a second time delay integration (TDI) sensor.
-
14. An apparatus for optical inspection of an object, having upper and lower faces, so as to detect defects existing on the object, the apparatus comprising:
-
i. an illumination system providing first and second beams of radiation simultaneously directed respectively onto a first area of the object and a second, different area of the object;
ii. a sensing system mounted in the vicinity of the object and simultaneously sensing a light component of the first beam reflected from the upper face of the object and a light component of the second beam transmitted through the upper and lower faces of the object and providing output signals representative thereof;
iii. a light directing system directing the reflected and transmitted light components onto the sensing system; and
iv. a processor coupled to the sensing system for receiving the output signals;
representative of the reflected and transmitted light components and for analyzing the signals so as to provide data indicative of said defects.- View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23)
-
-
28. A method for inspecting an object having upper and lower faces for detecting defects existing on the object, said method comprising:
-
a) providing first and second beams of radiation;
b) directing the first beam of radiation onto the object and sensing a light component reflected from one face of the object;
c) directing the second beam of radiation onto the object and sensing a light component transmitted through the upper and lower faces of the object;
d) simultaneously acquiring first and second images of the object, wherein the first image is formed by directing the reflected light component to a first sensor located on a first side of the object and the second image is formed by directing the transmitted light component to a second sensor located on said first side of the object; and
e) analyzing said first and second images so as to provide data indicative of said defects. - View Dependent Claims (29, 30, 31, 32, 33, 34)
-
-
35. An apparatus for optical inspection of an object, having upper and lower faces, so as to detect defects existing on the object, the apparatus comprising:
-
i. an illumination system providing first and second beams of radiation simultaneously directed onto the object;
ii. a sensing system mounted in the vicinity of the object and comprising a first sensor located on a first side of the object and a second sensor located on said first side of the object for simultaneously sensing a light component of the first beam reflected from the upper face of the object and a light component of the second. beam transmitted through the upper and lower faces of the object and providing output signals representative thereof;
iii. a light directing system directing the reflected and transmitted light components;
onto the sensing system; and
iv. a processor coupled to the sensing system for receiving the output signals representative of the reflected and transmitted light components and for analyzing the signals so as to provide data indicative of said defects. - View Dependent Claims (36, 37, 38, 39, 40, 41)
-
-
42. A method for inspecting an object having upper and lower faces for detecting defects existing on the object, said method comprising:
-
a) providing first and second beams of radiation;
b) directing the first beam of radiation onto the object and sensing a light component reflected from one face of the object;
c) directing the second beam of radiation onto the object and sensing a light component transmitted through the upper and lower faces of the object;
d) simultaneously acquiring first and second images of the object, wherein the first image is formed by directing the reflected light component to a first multi-element sensor and the second image is formed by directing the transmitted light component to a second multi-element sensor; and
analyzing said first and second images so as to provide data indicative of said defects. - View Dependent Claims (43, 44, 45, 46, 47, 48)
-
-
49. An apparatus for optical inspection of an object, having upper and lower faces, so as to detect defects existing on the object, the apparatus comprising:
-
i. an illumination system providing first and second beams of radiation simultaneously directed onto the object;
ii. a sensing system mounted in the vicinity of the object and comprising first and second sensors each comprising a respective multi-element sensor, said first and second sensors respectively and simultaneously sensing a light component of the first beam reflected from the upper face of the object and a light component of the second beam transmitted through the upper and lower faces of the object and providing output signals representative thereof;
iii. a light directing system directing the reflected and transmitted light components onto the sensing system; and
iv. a processor coupled to the sensing system for receiving the output signals representative of the reflected and transmitted light components and for analyzing the signals so as to provide data indicative of said defects. - View Dependent Claims (50, 51, 52, 53, 54, 55)
-
Specification