Method and apparatus for a fringe direct writing system

• US 6,268,893 B1
• Filed: 03/11/1997
• Issued: 07/31/2001
• Est. Priority Date: 03/11/1996
• Status: Expired due to Fees

• Current Assignee: Viavi Solutions, Inc. (Lumentum Holdings Inc.)
• Original Assignee: American Bank Note Holographics, Inc. (Lumentum Holdings Inc.)
• Inventors: Kang, Der-Kuam, OʼBoyle, Lily
• Primary Examiner(s): Sikes, William L.
• Assistant Examiner(s): Duong, Tai V.
• Application Number:
  US08/815,081
• Time in Patent Office: 1,603 Days
• Field of Search: 349/1, 349/2, 349/4, 349/57, 349/64, 347/239, 347/255, 359/3, 359/9, 359/10, 359/22, 359/30, 359/31, 359/35, 359/900
• US Class Current: 349/2
• CPC Class Codes: G03H 1/0891 Processes or apparatus adapted to convert digital holographic data into a hologram G03H1/2294 takes precedence
• CPC Class Codes: G03H 2001/048 Parallel printer, i.e. a fringe pattern is reproduced

Abstract

A structure and method of operation of a fringe direct writing system to produce a hologram or the like. The apparatus is roughly classified into four parts: an illumination part; an image display and optical imaging part; an optically autofocusing part; and a two dimensional moveable stage part. The method of operation directly images a pattern, which is previously calculated by computer and displayed on the LCD panel, onto a recording material. This method affords the possibility to write a fringe pattern in a large region within a short period of time.

Claims

1. A fringe direct writing system comprising:

a light source for projecting and transmitting light;

an LCD display positioned to receive said transmitted light to alter said transmitted light to produce and project an image;

an imaging lens disposed downstream of said LCD display, said imaging lens manipulating said image for further processing;

an objective lens positioned to receive said image from said imaging lens and project a reduced image onto a photo-material plate, whereby said photo-material plate reacts to said image to form a corresponding image thereon;

a moveable stage capable of selectively moving throughout a two dimensional plane, wherein said photo-material plate is disposed on said moveable stage such that said moveable stage is moved to selectively expose a portion of said photo-material plate to said reduced image; and

a computer to control an operation of said direct writing system, whereby said computer generates a fringe pattern to be displayed by said LCD display, selectively operates a high speed shutter disposed upstream of said LCD display to control an exposure timing; and

selectively controls said moveable stage to facilitate the generation of a predetermined image on said photo-material plate.

2. A fringe direct writing system comprising:

a light source for projecting and transmitting light;

an LCD display positioned to receive said transmitted light to alter said transmitted light to produce and project an image;

an imaging lens disposed downstream of said LCD display, said imaging lens manipulating said image for further processing;

an objective lens positioned to receive said image from said imaging lens and project a reduced image onto a photo-material plate, whereby said photo-material plate reacts to said image to form a corresponding image thereon; and

a rotation diffuser disposed between said light source and said LCD display, wherein said light source comprises a laser light source producing coherent light, said rotation diffuser serving to modulate said coherent light into incoherent light to avoid speckle noise.