Diffractive Optical Element for Hologram Exposure
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Solution Overview
Problem
Current methods for producing holograms in mass production are complex, slow, expensive, and prone to errors due to the use of multiple optical components and stepwise exposure processes.
Innovation Solution
A device and method utilizing a diffractive optical element to shape laser radiation, eliminating the need for a Powell lens, scanner, and aperture, allowing for simultaneous exposure of multiple areas and simplifying the optical structure, enabling efficient and robust hologram generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a Powell lens, scanner, and aperture are used to shape and direct the laser beam, then the hologram can be exposed with controlled area and shape, but the device complexity increases and the exposure process becomes slow and stepwise
Solution Approach 1:
The patent removes the Powell lens, scanner, and aperture from the optical system, extracting only the essential function of beam shaping. This is achieved by using a simplified optical arrangement with a laser source that directly projects the beam through a hologram master to the recording material, eliminating unnecessary components while maintaining exposure area control.
Solution Approach 2:
The patent makes the optical system multi-functional by using a single optical arrangement that can both shape the laser beam and enable simultaneous exposure of multiple areas. The system can adapt to different exposure requirements without requiring separate components for each function, thereby reducing overall device complexity.
2Manufacturing precision
If a scanner with rotating mirror is used to move the laser beam across the hologram master, then the exposure area can be defined, but the exposure process becomes stepwise and slow
Solution Approach 1:
The patent eliminates periodic scanning motion and replaces it with a static optical arrangement that enables simultaneous exposure. The laser beam is projected directly onto the hologram master and recording material without requiring sequential scanning, thereby converting a periodic process into a continuous one and significantly improving exposure speed.
Solution Approach 2:
The patent ensures continuous exposure action by removing the scanner and its associated stepwise motion. The laser beam continuously illuminates the hologram master and recording material simultaneously, maintaining constant useful action throughout the exposure process rather than interrupting it for sequential scanning.
3Manufacturing precision
If multiple optical components are used in the beam path, then the hologram can be generated with controlled parameters, but the cost increases and the system becomes prone to errors
Solution Approach 1:
The patent extracts and removes unnecessary optical components from the beam path, keeping only the essential elements required for hologram generation. This reduction in component count directly decreases the number of potential failure points and alignment issues, thereby improving system reliability while maintaining sufficient control over hologram parameters.
Solution Approach 2:
The patent achieves hologram parameter control through changes in the optical arrangement configuration rather than through multiple active components. By adjusting the positions and orientations of the remaining optical elements, the system maintains precise control over exposure parameters while minimizing the number of components that could introduce errors.
4Manufacturing precision
If stepwise exposure is used to cover the area to be copied, then the exposure can be controlled, but the production time increases
Solution Approach 1:
The patent merges multiple sequential exposure steps into a single simultaneous exposure operation. By using a static optical arrangement that projects the laser beam directly onto the entire hologram master and recording material at once, the system combines what was previously separate time-consuming steps into one efficient operation, thereby reducing production time while maintaining exposure control.
Solution Approach 2:
The patent prepares the optical arrangement in advance to enable direct projection onto the entire exposure area. The optical components are pre-positioned and configured so that when exposure begins, the entire area is illuminated simultaneously without requiring preliminary scanning or sequential positioning, thereby eliminating time loss associated with stepwise preparation.
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 simplifies the hologram generation process, reduces costs and errors, and allows for the simultaneous production of multiple holograms on security documents in a single work step, enhancing efficiency and robustness.
Implementation Method 1
a diffractive optical element (22) arranged in a beam path of an optical arrangement (20) such that laser radiation (5) emitted by the laser radiation source (21) and transmitted through the diffractive optical element (22) is focused onto at least one further beam plane (17) in a beam path of the optical arrangement (20), thereby illuminating at least one further exposure area (10)
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a device (1) for generating a hologram, comprising an optical arrangement (20), wherein the optical arrangement (20) has at least one laser radiation source (21), a diffractive optical element (22), and a master image (23) along an optical axis, in or on which a holographic recording material (8) to be exposed and a hologram master (9) can be arranged, and wherein the diffractive optical element (22) is configured to focus a laser radiation (5) emitted by the laser radiation source (21) and transmitted through the diffractive optical element (22) onto a beam plane (17) in a beam path of the optical arrangement (20) in a focal plane (24), thereby irradiating an exposure area (10) that corresponds to an area (25) to be exposed for generating the hologram. The invention further relates to an associated method.