Thomas G Pitts

US Patent:

44144768, Nov 8, 1983

Filed:

Jun 19, 1981

Appl. No.:

6/275203

Inventors:

Edward L. Maddox - Lexington MA
Thomas E. Pitts - Warren RI

Assignee:

SW Industries, Inc. - Providence RI

International Classification:

G01N 2188

US Classification:

250563

Abstract:

An optical sensing system that detects the angular orientation of weft threads in a moving web of a textile has a sensor array that receives light transmitted through the web from a light source. The sensor array is preferably a single monolithic chip that includes a radial pattern of photosensitive areas that each generate an electrical signal proportional to the total intensity of the light incident on the area. The areas are elongated and narrow so the moving shadow of a weft thread passing over the area will modulate the output signal. The modulation is strongest when the thread is generally aligned with the area. Electronic circuitry generates a DC signal associated with each area that is proportional both to the magnitude and frequency of the modulation of the signal. The circuitry also compares these signals, selects the largest one, and generates an analog output voltage characteristic of the area associated with the largest signal. The circuitry optionally further includes a feedback circuit responsive to the selected maximum signal which controls a variable power supply for the light source and a switched gain amplifier responsive to extremes of light source voltage level.

US Patent:

46563601, Apr 7, 1987

Filed:

Oct 19, 1984

Appl. No.:

6/662701

Inventors:

Edward L. Maddox - Lexington MA
Thomas E. Pitts - Warren RI

Assignee:

SW Industries, Inc. - Providence RI

International Classification:

G01N 2186

US Classification:

250571

Abstract:

An optical sensing system that detects the angular orientation of weft threads in a moving web of a textile has a sensor array that receives light transmitted through the web from a light source. The sensor array is preferably a single monolithic chip that includes a radial pattern of photosensitive areas that each generate an electrical signal proportional to the total intensity of the light incident on the area. The areas are elongated and narrow so the moving shadow of a weft thread passing over the area will modulate the output signal. The modulation is strongest when the thread is generally aligned with the area. Electronic circuitry generates a DC signal associated with each area that is proportional both of the magnitude and frequency of the modulation of the signal. The circuitry also compares these signals, selects the largest one, and generates an analog output voltage characteristic of the area associated with the largest signal. The circuitry optionally further includes a feedback circuit responsive to the selected maximum signal which controls a variable power supply for the light source and a switched gain amplifier responsive to extremes of light source voltage level.