Polarized VCSEL Array with Diffractive Optical Element for Biometric Authentication
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Solution Overview
Problem
Existing authentication systems in mobile devices require cutouts in the display for cameras, reducing the available display area and increasing hardware costs and complexity.
Innovation Solution
An optoelectronic apparatus that emits an infrared light pattern and flood light using a single projector, with a refractive and/or diffractive optical element and a polarization-sensitive beam splitter, allowing for biometric face authentication without visible camera cutouts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two independent VCSEL arrays are used for flood and dot projection, then both illumination functions are achieved, but the emissive area increases requiring larger transparent areas
Solution Approach 1:
The patent merges flood and dot projection functions into a single VCSEL array by using a diffractive optical element to split the light into different diffraction orders. The zeroth order provides flood illumination while first and second orders create dot patterns, eliminating the need for separate VCSEL arrays and reducing the required transparent area.
Solution Approach 2:
A single VCSEL array is designed to perform multiple functions simultaneously - flood illumination and dot projection - by utilizing different diffraction orders of the same light source. This multi-functional approach reduces hardware complexity and minimizes the transparent area requirement while maintaining both illumination capabilities.
2Adaptability or versatility
If two independent VCSEL arrays are used for flood and dot projection, then both illumination functions are achieved, but hardware complexity and costs increase
Solution Approach 1:
The patent combines flood and dot projection into a single integrated system using one VCSEL array and a diffractive optical element. This merging eliminates the need for separate control circuits, mounting structures, and alignment mechanisms required for two independent arrays, thereby reducing hardware complexity and manufacturing costs.
Solution Approach 2:
The single VCSEL array with diffractive optical element serves as a universal illumination device that can generate both flood and dot patterns. This multi-functional design reduces the overall component count, simplifies the optical train, and lowers system complexity while maintaining the versatility needed for authentication.
3Adaptability or versatility
If two independent VCSEL arrays are used for flood and dot projection, then both illumination functions are achieved, but the number of semitransparent areas increases from 1 to 2
Solution Approach 1:
The patent merges both illumination functions into a single optical path that passes through one semitransparent display area. The diffractive optical element separates the light into different orders within the same physical space, allowing both flood and dot projections to exit through the same display region rather than requiring separate transparent areas.
4Adaptability or versatility
If VCSELs are placed with offset from optical axis to achieve flood and dot projection, then both functions are achieved, but field of illumination does not coincide
Solution Approach 1:
The diffractive optical element acts as an intermediary that takes the light from a single on-axis VCSEL array and redirects it into different diffraction orders. This intermediary component enables both flood and dot projection functions while maintaining precise alignment of the fields of illumination, eliminating the need for offset VCSEL placements and the associated alignment precision requirements.
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 secure biometric face authentication with a maximized display area by using semitransparent display areas for optical components, reducing hardware requirements and costs.
Implementation Method 1
The diffractive optical element is configured for diffracting light from the at least one array of light emitters into a plurality of diffraction orders
Implementation Method 2
The refractive optical element is configured for focusing light from the at least one array of light emitters onto the display region
Implementation Method 3
The polarization beam splitter is configured for separating light into a first polarization component and a second polarization component
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An optoelectronic apparatus (112) configured for emitting at least one infrared light pattern comprising a plurality of infrared light beams and for emitting infrared flood light is proposed, comprising: - at least one refractive and/or diffractive optical element (114); - at least one polarization-sensitive beam splitter (116); - at least one light emitter structure (118) comprising at least one first array (120) of light emitters and at least one second array (122) of light emitters, wherein the first array (120) is configured for emitting light with a first polarization and the second array (122) is configured for emitting light with a second polarization, different from the first polarization, - at least two illumination paths comprising a light pattern illumination path and a flood light illumination path, wherein the light pattern illumination path comprises a pattern light source (124) comprising one of the first array (120) or the second array (122), wherein the pattern light source (124) is arranged at a back focal length of the optical element (114), wherein the optical element (114) is configured for collimating and/or replicating light from the pattern light source (124), thereby forming the pattern light source (124) configured for emitting the infrared light pattern, wherein the flood light illumination paths comprises a flood light source (126) comprising the other one of the first array (120) or the second array (122), wherein the flood light source (126) is arranged with an offset to the back focal length of the optical element (114), wherein the optical element (114) is configured for defocusing light from the flood light source (126), thereby forming the flood light source configured for emitting the infrared flood light, wherein a reflection plane of the beam splitter (116) is oriented such that light emitted from one of the pattern light source (124) or the flood light source (126) passes through the beam splitter (116) unaltered to the optical element (114) and that light emitted from the other one of the pattern light source (124) or the flood light source (126) gets reflected towards the optical element (114).