Polygonal Drum Hologram Replication via Parallel Laser Exposure
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Solution Overview
Problem
Existing methods for producing large numbers of high-quality reflection volume holograms are inefficient due to long exposure times and quality impairments when using rotating drums, leading to high costs and reduced productivity.
Innovation Solution
A method and device utilizing a uniformly rotating polygonal drum with coherent parallel laser exposure, combined with a pressing device to maintain film adhesion and precise guidance, allowing simultaneous exposure of multiple master surfaces and enabling continuous, uniform exposure of large holograms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotating drum is used to continuously expose holograms, then productivity increases, but the incidence angle varies across the exposure area causing quality impairment
Solution Approach 1:
The drum is divided into multiple polygonal surfaces (e.g., square drum with four surfaces), each dedicated to exposing one master hologram. This segmentation allows each surface to be exposed under controlled conditions while the drum rotates to the next surface, maintaining both speed and quality.
Solution Approach 2:
The drum rotates uniformly and continuously, dynamically positioning different polygonal surfaces into the exposure area. This dynamic rotation enables continuous production while maintaining consistent exposure conditions through precise control of the rotation speed and positioning.
2Productivity
If the drum rotates faster to increase productivity, then production speed increases, but the quality of copies deteriorates
Solution Approach 1:
By dividing the drum into multiple polygonal surfaces, the system can rotate faster overall while each individual surface receives adequate exposure time. The segmentation allows parallel processing of multiple holograms, maintaining quality through controlled exposure of each segment.
Solution Approach 2:
The drum rotates continuously without interruption, keeping the exposure process continuous. Multiple master holograms are exposed in sequence on different polygonal surfaces, eliminating idle time while maintaining consistent exposure conditions for each hologram.
3Area of stationary object
If a divergent laser beam is used to expose large master holograms, then the entire area can be exposed, but the incidence angle is not identical across the surface impairing copy quality
Solution Approach 1:
The exposure system is segmented into multiple polygonal surfaces on the drum, each receiving exposure from the laser beam under controlled incidence angles. This segmentation allows the use of a divergent beam to cover large areas while maintaining quality through precise angular control of each segment.
Solution Approach 2:
Each polygonal surface on the drum is designed to receive the laser beam at a specific, controlled incidence angle appropriate for its position. This local quality approach ensures that each area receives optimal exposure conditions even when using a divergent beam to cover large总面积.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly increases productivity while maintaining high-quality hologram reproduction, making large hologram production more economical and efficient.
Implementation Method 1
a holographic film is placed over a master hologram and exposed to light
Implementation Method 2
a coherent parallel radiation which occurs on the entire master surface
Implementation Method 3
a pressing device to maintain film adhesion and precise guidance
Data Source
AI summary
A method and a device are described for producing copies/replica of a volume reflection hologram wherein a holographic film (4) is guided over a drum with polygon cross-section having at least two planar (polygon) master surfaces (3) to each of which at least one master (7) is attached in the circumferential direction, where the film is brought into contact with at least one master hologram (7) and its entire surface is exposed to laser. It is essential that to at least one of the master surfaces (5) with the film guided over it, a laser exposure unit (22) is assigned which allows full exposure of the respective master surface to parallel, coherent laser beams (6), and that the at least one exposure unit (22) follows section wise the rotational movement of the drum by a splitting angle with equal velocity and exposes the corresponding master surface (5) to then be reset quickly again and perform the same angular displacement and exposure together with the next master surface. In this manner, a highly productive multiplication even of large reflection holograms in high quality is possible.