Method and apparatus for correcting light non-uniformity in an LCD photographic printer

Claim 1

An apparatus for printing an image onto a photosensitive media, comprising: a) a light source for producing an exposure light; b) an imaging active matrix liquid crystal display for producing an image through which said exposure light passes for printing said image onto a photosensitive material; c) a correction active matrix crystal display positioned between said imaging active matrix liquid crystal display said light source for correcting non-uniformity in said optical exposure system; and d) means for determining the intensity distribution of said exposure light and for controlling said corrective active matrix display in response thereto.

Claim 2

An apparatus for printing an image onto a photosensitive media, comprising: a) a light source for producing an exposure light; b) an imaging active matrix liquid crystal display for producing an image through which said exposure light passes for printing said image onto a photosensitive material; c) a correction active matrix crystal display positioned between said imaging active matrix liquid crystal display said light source for correcting non-uniformity in said optical exposure system; and d) means for determining the intensity distribution of said exposure light and for controlling said corrective active matrix display in response thereto.

Claim 11

A method for correcting light non-uniformity of an imaging system which uses an active matrix liquid crystal to expose an image on photosensitive media by passing exposure light through said active matrix liquid crystal display and a corrective active matrix liquid crystal display for correcting the exposure light intensity, said method comprising the steps of: a) measuring the light intensity distribution of the light passing through said active matrix liquid crystal for obtaining a first distribution value; b) comparing said first distribution value with a predetermined light intensity distribution; c) determining corrective intensity distribution values for driving said corrective liquid crystal; d) applying said corrective values to said corrective active matrix liquid crystal display; and e) repeating steps a), b), and c) until measured distribution values are within predetermined limits.

Claim 12

A method for correcting light non-uniformity of an imaging system which uses an active matrix liquid crystal to expose an image on photosensitive media by passing exposure light through said active matrix liquid crystal display and a corrective active matrix liquid crystal display for correcting the exposure light intensity, said method comprising the steps of: a) measuring the light intensity distribution of the light passing through said active matrix liquid crystal for obtaining a first distribution value; b) comparing said first distribution value with a predetermined light intensity distribution; c) determining corrective intensity distribution values for driving said corrective liquid crystal; d) applying said corrective values to said corrective active matrix liquid crystal display; and e) repeating steps a), b), and c) until measured distribution values are within predetermined limits.

Claim 13

A method of calibrating a printing apparatus which uses an active matrix liquid crystal to expose an image on photosensitive media by passing exposure light through said active matrix liquid crystal display and a corrective active matrix liquid crystal display for correcting the exposure light intensity, said method comprising the steps of: a) placing said corrective active matrix liquid crystal display in the clear mode; b) placing said imaging active matrix liquid crystal display at a first intensity setting; c) measuring said intensity distribution of said exposure light so as to obtain a first pixel gain map of said exposure light for said first setting; d) placing said imaging active matrix liquid crystal matrix display at a second intensity setting different from said first intensity setting; e) measuring said intensity distribution of said exposure light so as to obtain a second pixel gain map of said exposure light for said second setting; f) using said first, and second pixel maps so as to obtain a system response; g) determining a corrective map for use in calculating corrective values for said corrective active matrix liquid crystal display; and h) applying said corrective values to said corrective active matrix liquid crystal display.

Claim 14

A method of calibrating a printing apparatus which uses an active matrix liquid crystal to expose an image on photosensitive media by passing exposure light through said active matrix liquid crystal display and a corrective active matrix liquid crystal display for correcting the exposure light intensity, said method comprising the steps of: a) placing said corrective active matrix liquid crystal display in the clear mode; b) placing said imaging active matrix liquid crystal display at a first intensity setting; c) measuring said intensity distribution of said exposure light so as to obtain a first pixel gain map of said exposure light for said first setting; d) placing said imaging active matrix liquid crystal matrix display at a second intensity setting different from said first intensity setting; e) measuring said intensity distribution of said exposure light so as to obtain a second pixel gain map of said exposure light for said second setting; f) using said first, and second pixel maps so as to obtain a system response; g) determining a corrective map for use in calculating corrective values for said corrective active matrix liquid crystal display; and h) applying said corrective values to said corrective active matrix liquid crystal display.

Claim 16

A method of calibrating a printing apparatus which uses an active matrix liquid crystal to expose an image on photosensitive media by passing exposure light through said active matrix liquid crystal display and a light exposure corrective device for correcting the exposure light intensity at discrete locations, said method comprising the steps of: a) placing said imaging active matrix liquid crystal display at a first intensity setting; b) measuring said intensity distribution of said exposure light so as to obtain a first pixel gain map of said exposure light for said first setting; c) placing said imaging active matrix liquid crystal matrix display at a second intensity setting different from said first intensity setting; d) measuring said intensity distribution of said exposure light so as to obtain a second pixel map of said exposure light for said second setting; e) using said first and second pixel maps so as to obtain a system response; f) determining a corrective gain map for use in calculating corrective values for said corrective active matrix liquid crystal display; and g) applying said corrective values to said light corrective device.

Claim 17

A method of calibrating a printing apparatus which uses an active matrix liquid crystal to expose an image on photosensitive media by passing exposure light through said active matrix liquid crystal display and a light exposure corrective device for correcting the exposure light intensity at discrete locations, said method comprising the steps of: a) placing said imaging active matrix liquid crystal display at a first intensity setting; b) measuring said intensity distribution of said exposure light so as to obtain a first pixel gain map of said exposure light for said first setting; c) placing said imaging active matrix liquid crystal matrix display at a second intensity setting different from said first intensity setting; d) measuring said intensity distribution of said exposure light so as to obtain a second pixel map of said exposure light for said second setting; e) using said first and second pixel maps so as to obtain a system response; f) determining a corrective gain map for use in calculating corrective values for said corrective active matrix liquid crystal display; and g) applying said corrective values to said light corrective device.