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Expired Canadian patentCanada

Variable proportional fill flash

CA 1180746 A · Owner: Polaroid Corporation · Inventors: Rodriguez, Marie T.; Lim, James K.; Coppa, Richard J.

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

A photographic exposure and flash fire control system initially measures ambient scene light and subsequently utilizes the results of that measurement to control the amount of artificial illumination provided during the exposure interval. The initial measurement of ambient scene light below a first select level provides for a maximum flash output while conversely the initial measurement of ambient scene light above a second select level greater than the first select level provides for minimum flash output. The initial measurement of ambient scene light between the aforementioned first and second levels provides for a flash output which progressively varies between the aforementioned minimum …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted January 8, 1985. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended January 8, 2002.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledJanuary 9, 1981
GrantedJanuary 8, 1985
Term endedJanuary 8, 2002
Patent numberCA 1180746 A
Classification (IPC)G03B15/05 +1 more

Timeline

Timeline From CIPO dates

1982198519881991199419972000Application filedJan 9, 1981Patent grantedJan 8, 1985Term endedJan 8, 2002

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.