Miniature Structured Light Illuminator Using Microlens Array
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Solution Overview
Problem
Conventional structured light illumination systems for 3-D imaging and gesture recognition face limitations in brightness and resolution due to light loss and the need for large arrays of low-power surface emitting LEDs or VCSELs, which are not suitable for compact handheld devices.
Innovation Solution
A miniature optical module integrating surface emitting light sources with a microlens array to generate structured light patterns with minimal intensity loss and distortion, using a compact design suitable for handheld devices, allowing for varied beam deflection and pattern generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional structured light illumination systems use large arrays of surface emitting LEDs or VCSELs, then illumination intensity can be increased, but device size and complexity increase making them unsuitable for compact handheld devices
Solution Approach 1:
The patent combines the light source array with a microlens array in an integrated structure where each microlens is positioned directly over corresponding light emitting elements. This merging eliminates the need for separate illumination and focusing systems, achieving compact form factor while maintaining high illumination intensity through efficient light coupling and directional control.
Solution Approach 2:
The microlens array is nested within or directly coupled to the light source array structure, with each microlens positioned over individual or groups of light emitting elements. This nesting approach allows the focusing function to be embedded within the illumination system itself, reducing overall device volume while preserving both brightness and spatial control capabilities.
2Ease of manufacture
If separate pattern generators such as masks or DOEs are used, then structured light patterns can be generated, but significant light loss occurs affecting brightness and resolution
Solution Approach 1:
The patent extracts the pattern generation function from separate physical masks or DOEs and implements it directly through the microlens array structure itself. The microlenses are arranged in specific patterns and can be selectively activated to generate structured light patterns without requiring additional opaque masking elements that would block and lose light.
Solution Approach 2:
The microlens array serves multiple functions simultaneously: it focuses light to increase illumination intensity, defines the structured light pattern geometry, and enables selective region activation. This multi-functionality eliminates the need for separate pattern generation components that would cause light loss through absorption or blocking.
3Power
If VCSEL arrays are used as light sources, then higher illumination intensity can be achieved, but the need for large arrays of low-power sources increases device complexity
Solution Approach 1:
The patent merges VCSEL light emitting elements with corresponding microlenses in an integrated array structure where each VCSEL is paired with or grouped under a microlens. This combination allows individual low-power VCSELs to be efficiently focused and directed, achieving high overall illumination intensity without requiring an excessively large number of elements, thereby reducing array complexity.
Solution Approach 2:
The microlens array provides localized focusing and beam shaping for specific regions or individual VCSEL elements within the array. This local optical control allows selective activation and optimization of different array regions, enabling high illumination power in specific areas of interest while keeping the overall device complexity manageable through regional rather than global optimization.
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 solution enables high-resolution, high-power structured light patterns with improved brightness and polarization control, suitable for compact devices like smartphones and tablets, enhancing 3-D imaging and gesture recognition capabilities.
Implementation Method 1
integrating surface emitting light sources with a microlens array to generate structured light patterns
Implementation Method 2
A miniature optical module integrating surface emitting light sources with a microlens array to generate structured light patterns with minimal intensity loss and distortion, using a compact design suitable for handheld devices, allowing for varied beam deflection and pattern generation
Data Source
AI summary
A miniature structured light illuminator is provided. The miniature structured light illuminator uses a semiconductor surface emitting array including VCSEL or RC-LED array and an array of microlens elements to generate a wide range of structured light illumination patterns. The emission beam from a surface emitter array may be selectively directed, steered, focused or expanded, by applying a lateral displacement of the microlens array, such that centers of the emission beam and microlens array are misaligned. Emitted beams may be directed through small optical components to project the structured light pattern to a distant plane. The surface emitting arrays may be configured in addressable form to be activated separately for continuous or pulsed operation with very fast pulses having <100 ps risetime. A compact structured light illuminator module with projection optics is provided in very small physical size (˜6×6×3 mm3) suitable to configure in a handheld device.