LiDAR Sensor Pixel Pitch Layout for Wider Peripheral Viewing
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Solution Overview
Problem
Conventional distance measurement devices using two-dimensional array sensors have uniform pixel pitches, leading to reduced sensitivity at the peripheral portions, limiting the measurable distance and viewing angle due to narrower incident angles and decreased light reception.
Innovation Solution
A distance measurement device with a varying pixel pitch in the light receiving element, where the pitch is wider at the peripheral areas, allowing for consistent incident angles and improved light reception across the sensor, reducing sensitivity differences between central and peripheral regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the respective pixels of the two-dimensional array sensor are arranged at a uniform pitch, then the manufacturing is simplified and the structure is regular, but the incident angle of reflected light is narrower at the peripheral portion and the sensitivity drops, limiting the measurable distance and viewing angle
Solution Approach 1:
The patent applies local quality by varying the pitch of unit pixels according to their position in the light receiving pixel area. Specifically, the pitch is set to be wider at positions farther from the central portion and closer to the peripheral portion. This non-uniform pitch distribution compensates for the narrower incident angles at peripheral regions, maintaining consistent sensitivity across the entire sensor array and expanding the measurable viewing angle.
2Device complexity
If the pitch of unit pixels is uniform across the light receiving element, then the device structure is simple and regular, but the measurable viewing angle is narrow due to reduced sensitivity at peripheral portions
Solution Approach 1:
The patent implements local quality by configuring different pitch values for unit pixels based on their spatial location. The pitch is increased toward the peripheral portions of the light receiving pixel area, which compensates for the geometric reduction in incident angle at these locations. This enables the sensor to maintain uniform sensitivity characteristics across the entire field of view, thereby expanding the measurable viewing angle without significantly increasing device complexity.
3Reliability
If a mechanical scanning mechanism is used to scan laser light, then the distance measurement can be performed with a single-pixel light receiving element, but the scanning mechanism is large, expensive, and has poor long-term reliability
Solution Approach 1:
The patent replaces the mechanical scanning mechanism with a two-dimensional array sensor that performs parallel distance measurement across multiple pixels simultaneously. By eliminating the mechanical scanner and using a fixed array of photodetectors arranged with position-dependent pitch, the system achieves improved reliability and reduced device complexity while maintaining the ability to measure distances across a wide field of view.
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 configuration enables a wider viewing angle for measurable distances by maintaining consistent sensitivity across the light receiving element, enhancing the device's range and accuracy.
Implementation Method 1
a light receiving element that receives the laser light reflected by the measurement target on a pixel-by-pixel basis
Implementation Method 2
a laser irradiation unit that irradiates a measurement target with laser light
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A distance measurement device according to the present disclosure includes: a laser irradiation unit that irradiates a measurement target with laser light; and a laser light receiving unit including a light receiving element that receives the laser light reflected by the measurement target on a pixel-by-pixel basis. Furthermore, the pitch of the unit pixels of the light receiving element varies with location in a light receiving pixel area. A mobile apparatus according to the present disclosure is equipped with a distance measurement device having the above configuration.