Inventor

Keith A. Engstrom

Inventor

Arlington Heights, IL, US

Overview

9→

Patents

1976–1996

Patent span

Electricity

Primary field (CPC H)

Patents· 9 as inventor

Public. Assignee & technology derived from the patent record. Each patent links to its LexDana page.

H03Kprimary

H03KPulse technique21%

G06FElectric digital data processing16%

H03MCoding16%

H04LTransmission of digital information, e.g. telegraphic communication11%

G01LMeasuring force, stress, torque, work, mechanical power, mechanical efficiency, or fluid pressure5%

G11CStatic stores5%

H01HElectric switches5%

H03FAmplifiers5%

H05KPrinted circuits5%

H10FInorganic semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation5%

PatentTitleYear

5,541,623'Temperature compensated opto-electronic circuit and mouse using same'1996 5,446,259'Method for producing opto-electronic circuit using laser-trimming device'1995 4,704,601'Keyboard data entry system with hysteresis'1987 4,611,406'Enclosure for electrical data input apparatus'1986 4,517,553'N-Key rollover keyboard'1985 4,479,392'Force transducer'1984 4,390,866'Keyboard with electronic hysteresis'1983 4,028,696'Double depression magnetic keyswitch'1977 3,978,474'Keyboard with N-key lockout and two-key rollover protection'1976

Career & activity timeline

Assembled from patent assignee/location history and declaration credentials.

1976–1987Patents assigned to ILLINOIS TOOL WORKS (7)· patent assignee history

1976–1983Based in Arlington Heights, IL, US· patent location history

1984Based in Rolling Meadows, IL, US· patent location history

1985Based in River Grove, IL, US· patent location history

1986–1987Based in Barrington, IL, US· patent location history

1995–1996Patents assigned to ALPS ELECTRIC USA (2)· patent assignee history

1995–1996Based in Laguna Niguel, CA, US· patent location history

Inventor activity

Assignee and location history derived from the patent record.

Assignees

Assignee	Patents	Span
ILLINOIS TOOL WORKS	7	1976–1987
ALPS ELECTRIC USA	2	1995–1996

Locations

Location	Patents	Span
Arlington Heights, Illinois, US	3	1976–1983
Laguna Niguel, California, US	2	1995–1996
Barrington, Illinois, US	2	1986–1987
River Grove, Illinois, US	1	1985
Rolling Meadows, Illinois, US	1	1984