Tunable Liquid Crystal Panel for 3D Sensing
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Solution Overview
Problem
Current 3D sensing technologies, such as structured illumination, are limited by fixed focal lengths in projection lenses, which restrict the range of object resolution and are inefficient in terms of light usage, and the combination of flood and structured light systems in mobile devices is bulky and costly.
Innovation Solution
Incorporating a liquid crystal lens module with variable focal length in structured light projectors and a tunable liquid crystal panel to switch between structured and flood lights, enabling adjustable focusing and integration of both systems into a single unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed focal length projection lens is used in structured illumination, then the system structure is simple, but the range of object resolution is limited
Solution Approach 1:
The patent applies a liquid crystal lens module that can dynamically adjust its focal length between at least two different focusing states, allowing the structured light projector to resolve objects at different distances without changing the physical lens structure, thus improving adaptability while maintaining relatively simple system architecture
Solution Approach 2:
The patent changes the optical parameter (focal length) of the projection lens by using a liquid crystal lens module with variable focal length, enabling the system to adjust its focusing capability to resolve objects at different distances, thereby expanding the range of object resolution
2Adaptability or versatility
If an apodized lens is added to create a multifocal system, then the focusing range is improved, but light efficiency and resolution deteriorate
Solution Approach 1:
The patent introduces a liquid crystal lens module as an intermediary component between the light source and the diffractive optical element, which can selectively focus light at different focal lengths without the light loss associated with apodized lenses, thereby maintaining light efficiency while expanding focusing range
Solution Approach 2:
The patent uses a liquid crystal lens module that can change its focal length parameter dynamically, allowing the system to switch between different focusing states without the permanent optical modifications required by apodized lenses, thus preserving light efficiency while improving focusing range
3Measurement precision
If separate flood light and structured light systems are used for 3D face recognition, then recognition accuracy is improved, but device size and cost increase
Solution Approach 1:
The patent merges the flood light system and structured light system into a single integrated device by incorporating a liquid crystal lens module that can switch between flood light mode and structured light mode, thereby maintaining recognition accuracy while reducing device size and component count
Solution Approach 2:
The patent creates a multi-functional light projector that can operate in both flood light mode (for initial detection) and structured light mode (for precise 3D recognition) using the same optical path and liquid crystal lens module, eliminating the need for separate dedicated systems and reducing overall device complexity
4Adaptability or versatility
If a liquid crystal lens module with variable focal length is used, then the focusing range is enhanced, but device complexity increases
Solution Approach 1:
The patent uses a liquid crystal lens module that provides dynamic focal length adjustment capability, allowing the system to adapt to different object distances by changing the focal length parameter without adding multiple physical lenses or complex mechanical adjustment mechanisms, thus enhancing focusing range while keeping the device structure relatively compact
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 enhances the focusing range of structured light projectors, reduces device size and cost, and allows for efficient 3D sensing in mobile devices by integrating flood and structured light systems.
Implementation Method 1
The liquid crystal lens module is disposed on at least one of the path of the light beam and a path of the structured light and capable of controlling between at least two focusing state
Implementation Method 2
The diffractive optical element is disposed on a path of the light beam and configured to generate diffraction patterns so as to form the structured light
Data Source
AI summary
A tunable light projector including a light source, a fixed optical phase modulator, a tunable liquid crystal panel, and a driver is provided. The light source is configured to emit a light beam. The fixed optical phase modulator is disposed on a path of the light beam and configured to modulate phases of the light beam. The tunable liquid crystal panel is disposed on the path of the light beam from the fixed optical phase modulator and configured to switch the light beam between a structured light and a flood light. The driver is electrically connected to a first electrode layer and a second electrode layer of the tunable liquid crystal panel and configured to change a voltage difference between the first electrode layer and the second electrode layer, so as to switch the light beam between the structured light and the flood light.