3D Image Element With Fan-Like Pulse Light Conversion
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Solution Overview
Problem
Conventional three-dimensional image elements and optical radar devices face challenges in detecting objects at short distances with high accuracy and low cost, particularly in automotive applications, due to reduced light intensity and increased background noise, and struggle with scanning entire fields of view efficiently.
Innovation Solution
A three-dimensional image element with a light receiving unit featuring avalanche photodiodes in a two-dimensional matrix pattern, pixel storage elements with binary counters for pulse integration, and a signal processing circuit that reads data in parallel, combined with an optical radar device using pulse light illumination, optical scanning, and fan-like pulse light conversion for wide field coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scanning type optical radar is used to increase laser beam intensity at the object, then measurement precision is improved, but device complexity and cost increase due to mechanical scanning components
Solution Approach 1:
The patent replaces the mechanical scanning mirror with an optical conversion unit that uses optical elements (lenses or mirrors without moving parts) to scan the laser beam across the field of view. The light receiving unit includes pixels arranged in a matrix that detect reflected light from different angular positions, eliminating the need for mechanical oscillation while maintaining scanning functionality and measurement precision.
2Ease of manufacture
If a single-radiation type optical radar is used to reduce device complexity, then ease of manufacture is improved, but measurement precision deteriorates due to reduced laser beam intensity at the object
Solution Approach 1:
The patent transitions from a single-pixel detector to a two-dimensional matrix array of pixels. This dimensional expansion allows simultaneous detection of reflected light from multiple angular positions across the field of view, enabling the system to maintain high measurement precision without requiring high beam intensity or mechanical scanning.
Solution Approach 2:
The patent employs periodic pulse radiation of laser light through the optical conversion unit, which scans the beam across the field of view in a systematic sequence. This periodic scanning allows the single-radiation type system to collect distance information from all field of view regions over one cycle, maintaining measurement precision while keeping the device simple.
3Measurement precision
If TCSPC method is used to improve measurement precision, then distance accuracy is improved, but device complexity increases due to large circuit scale required in each pixel
Solution Approach 1:
The patent combines multiple pixels into integrated pixel units that collectively perform flight time measurement. Instead of requiring complex TCSPC circuits in each individual pixel, the system integrates the detection functions across the pixel matrix, reducing the circuit scale per pixel while maintaining overall measurement precision through the collective data from multiple pixels.
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 low-cost detection of object distances at short ranges before final pulse counting, improving accuracy and efficiency in detecting objects across a wide field of view without the need for complex mechanical scanning systems.
Implementation Method 1
pixels each including an avalanche photodiode that detects light in a Geiger mode
Implementation Method 2
an optical conversion unit to convert scanned pulse light into fan-like pulse light
Data Source
AI summary
A three-dimensional image element and an optical radar device that have low cost and are capable of detecting a distance to a measurement object at a close distance before a final result of counting the number of pulses is acquired are realized. A pixel storage element has a plurality of binary counters that integrate the number of electrical pulses at mutually different timings and the reading of data by a signal processing circuit and the integration are able to be performed in parallel.