Angled Reflector Depth Camera for Compact Laser Safety
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Solution Overview
Problem
Conventional depth cameras for time flight systems face challenges in miniaturization due to laser safety requirements, which necessitate increased size to maintain Class 1 laser safety, making them unsuitable for small form factor applications like display devices.
Innovation Solution
A depth camera design featuring a light source with an angled reflector that redirects and expands the light beam to increase the emission spot size while maintaining Class 1 laser safety, allowing for a smaller form factor by positioning the light source and reflector to manage the distance in a direction that is less restrictive for the device's dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diffusion optic is placed perpendicular to the emission path to increase the effective emission spot size for Class 1 laser safety, then laser safety is improved, but the camera depth dimension increases making it unsuitable for small form factor applications
Solution Approach 1:
The patent changes the orientation of the diffusion optic from perpendicular to the emission path (conventional approach) to at an acute angle (e.g., 30-60 degrees) relative to the emission path. This angular reorientation allows the light to travel a longer path through the diffusion optic, effectively increasing the emission spot size for laser safety while keeping the device depth compact by utilizing the lateral dimension instead of the depth dimension.
2Power
If the light source power is increased to improve depth detection performance, then detection capability is improved, but the emission spot size must be larger to maintain Class 1 laser safety, increasing device size
Solution Approach 1:
The diffusion optic serves as an intermediary element between the light source and the external environment. By positioning it at an acute angle to the emission path, it mediates the light propagation, extending the effective emission area through increased optical path length within the diffusion medium, thereby enabling high power operation while maintaining laser safety.
3Reliability
If the distance between the light source and diffusion optic is increased to expand the emission spot size for laser safety, then Class 1 laser safety is achieved, but the device form factor increases beyond acceptable limits for display bezels
Solution Approach 1:
Instead of increasing the distance D along the depth direction (which increases device volume), the patent reorients the diffusion optic at an acute angle to the emission path. This allows the light to traverse a longer effective path through the diffusion material, expanding the emission spot size in a direction that does not significantly increase the device's external dimensions, thus maintaining compact form factor while achieving laser safety.
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
Enables the creation of a low-profile depth camera that can fit into tight spaces of display devices while ensuring Class 1 laser safety, allowing for smaller dimensions without compromising performance.
Implementation Method 1
an angled reflector for redirecting the beam of light from the natural emission path to a required direction of emission
Implementation Method 2
receiver optics for receiving and focusing the returning portions of the beam of light onto the detector array
Data Source
AI summary
The use of one or more angled or curved and diverging light pipes or reflectors placed in a light source's, e.g. diode's, emission path at appropriate distances, angles and divergence, such that a diode's emission spot size is modified and or redirected from the diode's natural emission path to alternative planes at angle to the diode's natural emission path so that a diode emission safe spot size can be achieved on any plane at angle to the original diode natural emission path at minimum distances from the diode's point of emission.