Multi-Diode Laser System with Offset Focal Points for Eye Safety
Solution Overview
Problem
Current laser scanning technologies face challenges in increasing laser intensity while adhering to eye safety regulations, particularly the IEC 60825 standard, which limits the aggregated radiation intensity to prevent eye exposure hazards.
Innovation Solution
The solution involves using multiple laser diodes emitting at different wavelengths with offset focal points and dynamic intensity control to ensure that the aggregated radiation intensity exceeds the maximum permissible exposure threshold without simultaneous exposure to the eye, allowing each diode to reach its maximum value independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple laser diodes are used to increase overall intensity, then the total radiation intensity can exceed safety thresholds, but the aggregated radiation intensity must still comply with maximum permissible exposure limits
Solution Approach 1:
The patent divides the laser system into multiple separate laser diodes (e.g., red, green, blue lasers) with offset focal points. Each laser diode operates independently with its own focal point positioned at different locations. This segmentation allows each laser to be controlled separately, enabling the overall system intensity to exceed safety thresholds while each individual laser remains below hazardous levels due to the spatial separation preventing simultaneous eye exposure.
2Illumination intensity
If laser intensity is increased to improve image quality, then brightness and visibility improve, but eye safety regulations limit the maximum permissible exposure
Solution Approach 1:
The patent introduces a spatial dimension offset between multiple laser focal points rather than simply increasing intensity in one dimension. By positioning focal points at different locations (e.g., offset by several millimeters), the system achieves higher overall brightness through multiple sources while maintaining safety compliance because the human eye cannot simultaneously receive hazardous radiation from all offset focal points.
3Adaptability or versatility
If multiple lasers are used to cover color gamut, then color versatility improves, but the aggregated intensity of all lasers must remain within safety limits
Solution Approach 1:
The patent employs multiple laser diodes segmented into different wavelength groups (red, green, blue) to cover the color gamut. Each laser type has its focal point offset from others, creating spatial separation. This allows full color versatility through combination of different lasers while the offset positioning ensures that not all lasers can simultaneously expose the eye, thereby permitting higher individual and aggregate intensities than would be possible with a single focused beam.
Data Source
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Figure 3~4
AI summary
A laser diode projecting apparatus which comprises: at least two laser diodes each emitting radiation towards a respective focal point at a pre-defined wavelength, and wherein the at least two respective focal points are separated from each other by at least an offset distance; and a power controller operative to control the intensity of the radiation emitted from each of the at least two laser diodes; and wherein the aggregated value of the radiation intensity emitted by all of the at least two laser diodes within a predefined period of time, exceeds a threshold value allowed for the maximum permissible exposure to radiation.