Method for writing holograms

• US 4,510,575 A
• Filed: 08/24/1982
• Issued: 04/09/1985
• Est. Priority Date: 08/24/1982
• Status: Expired due to Fees

• Current Assignee: Baybank Middlesex
• Original Assignee: Aerodyne Corporation
• Inventors: Caulfield, H. John, Mueller, Peter F.
• Primary Examiner(s): NOT, DEFINED
• Application Number:
  US06/410,901
• Time in Patent Office: 959 Days
• Field of Search: 364/521, 364/518, 364/524, 364/525, 364/488-491, 350/3.83, 350/3.84, 350/3.6, 350/3.75, 350/3.74
• US Class Current: 358/1.1
• CPC Class Codes: G03H 1/08 Synthesising holograms, i.e. holograms synthesized from objects or objects from hologramsusing electric digital computers G06F; G06T
• 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: Y10S 359/90 Methods

Abstract

A micro graphic representation such as a hologram is formed by directing from a computer to a display surface signals to form a very small portion of the graphic representation of the display surface, focusing a micro image of the display on a recording element, mechanically moving the recording element to a new position, optically measuring the new position and signalling the computer the precise new position and then sending to the display surface next signals to form on the display surface a next very small portion of the graphic representation with the position of the next portion modified to compensate for the difference between the measured position and the required position. The piece-by-piece display is repeated a large number of times to record an entire graphic representation. One embodiment of the invention is a hologram writer.

Claims

1. A method of forming a hologram comprising

storing in a computer a program corresponding to a hologram to be produced in precise geometric arrangement throughout said hologram,

forming on an electronic display surface in response to signals from said computer corresponding to said stored program a first portion of said pattern and optically projecting said first portion in micro size to a precisely positioned portion of a photoreceptor,

mechanically moving said photoreceptor with respect to said electronic display surface essentially the required pattern distance for the projection of a next portion of said pattern and optically sensing the distance of the mechanical motion,

forming on said electronic display surface a next portion of said pattern while compensating in the position on said electronic display surface for the difference between the sensed portion of said photoreceptor and the required position of said receptor, and

repeatedly repeating a large multiplicity of times the steps of mechanically moving said photoreceptor, sensing the distance of motion, forming a next image on said display surface and compensating for the difference between sensed position and required position to form an entire hologram having constant geometric characteristics throughout the hologram.

2. A method of hologram writing comprising programming to a computer system information corresponding to hologram fringes, separating the program into a large multiplicity of cell portions corresponding to a large multiplicity of hologram segments, directing from the computer to a cathode ray tube control signals sequentially for each of said individual cell portions, focusing from said cathode ray tube to a fine resolution photographic plate each of separate images of said cell portions in micro size, and moving said film between each successive cell portion to present for each cell portion a new corresponding plate area so that each cell portion is precisely positioned on said plate at the location for said cell portion in the hologram.