Tunable Light Projector Switching Structured and Flood Light
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Solution Overview
Problem
Current 3D sensing technologies, such as structured illumination, are limited by the need for multiple systems like flood light and structured light, which increase cost and volume in mobile devices, and suffer from fixed focal lengths that restrict the range of resolvable distances.
Innovation Solution
A tunable light projector using a tunable liquid crystal panel to switch between structured light and flood light, integrating both systems into a single unit, reducing device size and cost by controlling the light beam with a driver and electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flood light system and a structured light system are both used to achieve 3D face recognition, then the recognition accuracy is improved, but the device occupies large space and becomes costly
Solution Approach 1:
The patent merges the flood light system and structured light system into a single integrated projector by combining a flood light module and a structured light module sharing common components (light source, optical path, sensor), thereby reducing device volume and cost while maintaining dual functionality for accurate face recognition
Solution Approach 2:
The integrated projector is designed to perform multiple functions: it can operate as a flood light projector for initial detection and as a structured light projector for precise 3D mapping, allowing one device to replace two separate systems
2Device complexity
If a fixed focal length projection lens is used in structured illumination, then the system structure is simplified, but the distance range of resolvable objects is limited to a small range
Solution Approach 1:
The patent replaces the fixed focal length lens with a variable focal length projection lens that can dynamically adjust its focusing distance, enabling the system to resolve objects at different distances while maintaining a relatively simple overall structure
Solution Approach 2:
The projection lens parameters (focal length) are made changeable to adapt to different object distances, allowing the structured light system to maintain focus and resolution across a wider range of distances without significantly increasing system complexity
3Adaptability or versatility
If an apodized lens is added to the lens group to produce a multifocal system, then the distance range is extended, but light efficiency, 2D diffraction pattern points and resolution are reduced
Solution Approach 1:
Instead of using a static apodized lens that permanently reduces resolution, the patent employs a variable focal length lens that can dynamically adjust to provide sharp focus at different distances, maintaining high resolution and light efficiency across the extended distance range
Solution Approach 2:
The lens parameters are made dynamically adjustable rather than statically modified, allowing the system to optimize resolution and light efficiency for each focusing distance without the permanent degradation caused by apodization
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
The tunable light projector effectively reduces the volume and cost of devices by enabling both structured and flood light functions in a single system, enhancing the range of resolvable distances without compromising light efficiency or resolution.
Implementation Method 1
a liquid crystal layer (130) disposed between the first substrate (110) and the second substrate (112)
Implementation Method 2
a fixed optical phase modulator disposed on a path of the light beam and configured to modulate phases of the light beam
Data Source
AI summary
A tunable light projector including the following is provided. A light source is configured to emit a light beam. A fixed optical phase modulator is disposed on a path of the light beam and is configured to modulate phases of the light beam. A tunable liquid crystal panel is disposed on the path of the light beam and a partial region of the tunable liquid crystal panel is configured to electrically switch the light beam between a structured light and a flood light. A driver is configured to control the light source and control the tunable liquid crystal panel to switch the light beam between the structured light and the flood light. The tunable liquid crystal panel includes: a first substrate; a second substrate; a liquid crystal layer; a first electrode layer; and a second electrode layer.