Self-Aligned Light Angle Sensor Using PtSi PIN Photodiodes
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Solution Overview
Problem
Traditional optical angle sensors require lenses, which consume space, increase costs, and reduce light collection efficiency due to trenches used in lens-less detectors, making them less effective for precise angular measurements in compact devices.
Innovation Solution
A self-aligned light angle sensor design using Schottky platinum silicide (PtSi) PIN photodiodes with an intrinsic layer and a metal light block, eliminating the need for lenses and trenches, allowing for precise angular measurements without calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical lenses are used in angle sensors, then light focusing capability is improved, but device height and manufacturing cost increase
Solution Approach 1:
The patent removes the optical lens from the angle sensor system entirely, extracting the focusing function and replacing it with a direct geometric mapping approach where the aperture position relative to the photodetector array provides angular information without requiring light concentration
Solution Approach 2:
The patent replaces the optical mechanical system (lens) with a geometric arrangement system, where the spatial relationship between aperture and photodetectors directly encodes angular information through trigonometric relationships, eliminating the need for optical focusing components
2Measurement precision
If trenches are used in lens-less detectors to isolate photodetectors, then angular measurement capability is improved, but light collection efficiency decreases
Solution Approach 1:
The patent applies local quality by making the photodetector isolation regions selective - the aperture region maintains high light transmission quality while the peripheral isolation regions provide electrical separation, ensuring that light collection occurs primarily in the optimized aperture area without trench-induced losses
Solution Approach 2:
The patent transitions from two-dimensional planar photodetector arrangements to a three-dimensional geometric configuration where the aperture is positioned at a specific height above the photodetector array, creating angular sensitivity through vertical spacing rather than horizontal trench separation
3Measurement precision
If calibration procedures are implemented for zero angle alignment, then measurement accuracy is improved, but manufacturing complexity and time increase
Solution Approach 1:
The patent implements self-alignment through symmetric geometric design - the aperture is positioned equidistantly relative to left and right photodetector pairs, and the vertical arrangement ensures that normal incident light (zero angle) automatically produces equal signals on opposite photodetectors, providing self-calibrating zero-angle reference without external intervention
Solution Approach 2:
The patent uses controlled asymmetry in the signal processing - while the physical geometry is symmetric for self-alignment, the measurement algorithm intentionally creates asymmetric differential signals (left-minus-right) that directly represent angular deviation from the self-aligned zero position, converting geometric symmetry into measurement asymmetry
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 provides improved light collection efficiency and reduced manufacturing complexity, enabling precise angular measurements in compact devices without the need for calibration, thus addressing the limitations of traditional optical angle sensors.
Implementation Method 1
Schottky platinum silicide (PtSi) PIN photodiodes
Data Source
AI summary
Aspects of the embodiments are directed to non-contact systems, methods and devices for optical detection of objects in space at precise angles. This method involves the design and fabrication of photodiode arrays for measuring angular response using self-aligned Schottky platinum silicide (PtSi) PIN photodiodes (PN-diodes with an intrinsic layer sandwiched in between) that provide linear angular measurements from incident light in multiple dimensions. A self-aligned device is defined as one in which is not sensitive to photomask layer registrations. This design eliminates device offset between “left” and right” channels for normal incident light as compared to more conventional PIN diode constructions.