John P Schaefer

US Patent:

58382399, Nov 17, 1998

Filed:

Sep 10, 1996

Appl. No.:

8/712059

Inventors:

Howard Stern - Greenlawn NY
John Schaefer - Coram NY
Fereydoun Maali - New York NY

Assignee:

Robotic Vision Systems, Inc. - Hauppauge NY

International Classification:

G08B 1902

US Classification:

340583

Abstract:

A presence of a polarization altering substance on a specular surface is detected by transmitting light from a single strobed light source to the surface over a transmitting path and receiving the transmitted light from the surface. An intensity of the light is measured in both an optical non-isolator state and an isolator state by a same detector by delaying the non-isolated return light for a definite period of time before measuring it with the detector. The measured isolated and non-isolated intensities are converted to logarithmic form, range corrected, and compared to reference data established for the specific specular surface being investigated to detect the presence or absence of the polarization altering substance. Attenuation and backscattering effects of scattering and/or absorbing interference in the transmitted light are compensated so that the reference table is entered at the correct point. Using different intensities of transmitted light increases the dynamic range of the system.

US Patent:

6069565, May 30, 2000

Filed:

Oct 9, 1998

Appl. No.:

9/169619

Inventors:

Howard Stern - Greenlawn NY
John Schaefer - Coram NY
Fereydoun Maali - New York NY

Assignee:

Rosemount Aerospace Inc. - Burnsville MN

International Classification:

G08B 1902

US Classification:

340583

Abstract:

A presence of a polarization altering substance on a specular surface is detected by transmitting light from a single strobed light source to the surface over a transmitting path and receiving the transmitted light from the surface. An intensity of the light is measured in both an optical non-isolator state and an isolator state by a same detector by delaying the non-isolated return light for a definite period of time before measuring it with the detector. The measured isolated and non-isolated intensities are converted to logarithmic form, range corrected, and compared to reference data established for the specific specular surface being investigated to detect the presence or absence of the polarization altering substance. Attenuation and backscattering effects of scattering and/or absorbing interference in the transmitted light are compensated so that the reference table is entered at the correct point. Using different intensities of transmitted light increases the dynamic range of the system.

US Patent:

20200357704, Nov 12, 2020

Filed:

Nov 6, 2018

Appl. No.:

16/762011

Inventors:

- Wilmington MA, US
John Schaefer - Miller Place NY, US

Assignee:

Onto Innovation Inc. - Wilmington MA

International Classification:

H01L 21/66
G01B 11/06

Abstract:

Systems and methods for measuring a dimension of a 3D structure of a semiconductor device, such as height of a pad or bump supported by a film layer. The methods can include obtaining raw data implicating a height of the 3D structure with a laser triangulation sensor and adjusting the raw data with a compensation factor that accounts for effects of the film layer and a thickness of the film layer.