Laser Projector Safety Lens for Audience Beam Divergence
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Solution Overview
Problem
Current audience scanning projectors lack automatic power level control in different regions of the scan field and can be fooled into believing a safe condition exists, even when it is not, due to their reliance on scan-fail monitors that only monitor beam position change, not actual position, leading to potential hazards from concentrated beam power.
Innovation Solution
Incorporating a safety lens with adjustable optical power downstream the scanner to increase beam divergence only within the audience area, ensuring higher power usage while maintaining safety standards, and providing a fail-safe arrangement by projecting high divergence beams if the lens is removed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a scan-fail monitor is used to monitor beam position changes, then the projector can detect unsafe conditions, but it can be fooled into believing a safe condition exists when it is not
Solution Approach 1:
The patent introduces a safety lens as an intermediary optical element between the scanner and the audience area. This lens passively enforces beam divergence requirements without requiring complex active monitoring or control systems, thereby improving reliability while avoiding increased complexity
Solution Approach 2:
The safety lens is designed to be self-regulating based on beam position. When the beam is in the audience area, the lens automatically provides the required divergence; when the beam is above the audience area, the lens effect is naturally bypassed. This eliminates the need for complex active control systems
2Object-affected harmful factors
If beam divergence is increased within the audience area, then retinal damage is prevented, but beam power is reduced
Solution Approach 1:
The safety lens creates different beam qualities in different spatial regions. In the audience area, the lens produces high divergence beams that are safe for viewing. Above the audience area, the beam maintains low divergence for effective mirror targeting. This local differentiation resolves the contradiction between safety and power
3Adaptability or versatility
If a safety lens is added downstream the scanner, then beam divergence is controlled in different regions, but device complexity increases
Solution Approach 1:
The patent changes the optical parameter (divergence) by introducing a lens with specific focal length characteristics. The lens parameter is chosen so that its effect is naturally spatially differentiated - providing divergence where needed and being bypassed where not needed - thereby achieving adaptability without complex control systems
4Reliability
If the projector defaults to high divergence when the safety lens is removed, then safety is maintained and tampering is prevented, but beam power and effectiveness are reduced
Solution Approach 1:
The system is designed so that removal of the safety lens automatically triggers a fallback mode that produces high divergence beams. This preliminary anti-action prevents the harmful effect of tampering (lens removal) by ensuring safety is maintained even when the lens is absent, though at the cost of reduced beam effectiveness
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 solution allows for higher laser power usage within the audience area while ensuring safety by increasing beam divergence, preventing retinal damage and meeting Class 1 safety standards, while also enabling clear beam targeting above the audience and maintaining clarity of the projected effect.
Implementation Method 1
Incorporating a safety lens with adjustable optical power downstream the scanner to increase beam divergence only within the audience area
Data Source
AI summary
A laser light projector includes a laser beam generated by a laser light source, a scanner associated with the laser light source and having one or more moving mirrors capable of scanning the laser beam along X-Y coordinates, a scan-fail monitor and a safety-lens. The safety-lens includes at least one optical power, and is positioned and arranged for increasing the safety of the projected light within audience areas by increasing beam divergence in the audience, while keeping beam divergence low above the heads of the audience, thus allowing mirror targeting to occur.