Optical Distance Measuring Device Using Segmented Pixel Array

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Solution Overview

Problem

Conventional optical distance measuring devices are complex and costly, requiring sophisticated electronics and optics for accurate distance measurement, especially when measuring small or large distances, and often have limited dynamic range and signal-to-noise ratio.

Innovation Solution

A simplified optical distance measuring device with a light source that emits time-modulated light, using non-automatically focusing optics and a detection system where multiple pixels are illuminated simultaneously, allowing for independent evaluation of detection signals and optimization of signal-to-noise ratio through variable pixel configurations and distance determination devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional optical distance measuring devices use sophisticated electronics and focusing optics to achieve accurate distance measurement, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidelectronic component complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection surface is divided into multiple pixels arranged in a matrix, where each pixel independently detects light intensity. This segmentation allows the system to achieve spatially resolved distance measurements without requiring complex focusing optics, as each pixel captures information from a specific direction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The detector with multiple pixels serves multiple functions: it detects both the intensity and spatial distribution of reflected light, enabling distance measurement without separate imaging optics. The same pixel array that captures spatial information also performs the distance measurement function

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If three-dimensional cameras use imaging optics to map each surface area onto a pixel for spatially resolved distance measurement, then measurement precision is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvespatially resolved distance measurementVSAvoidoptical system manufacturing
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The detection surface is divided into multiple pixels arranged in a matrix, where each pixel independently detects light intensity. This segmentation allows the system to achieve spatially resolved distance measurements without requiring complex focusing optics, as each pixel captures information from a specific direction

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system uses a simplified optical path where reflected light is directly projected onto the pixel array without complex imaging optics. Each pixel effectively captures a 'copy' of the spatial information from the target surface, enabling manufacturing simplification while maintaining spatial resolution capability

Inventive Principle:
Principle #26Copying

3Measurement precision

If very short light pulses are emitted and very fast detection electronics are used to measure transit time, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvetransit time measurement accuracyVSAvoiddetection electronics speed requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system changes the measurement parameter from direct transit time measurement using ultra-fast electronics to phase shift measurement of continuously modulated light. By modulating the light intensity at a specific frequency and measuring the phase difference between transmitted and received signals, the system achieves accurate distance measurement with less demanding electronics

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The light intensity is modulated periodically over time, and the phase shift between the transmitted and detected light signal is used to determine the transit time. This periodic modulation approach allows accurate measurement using standard electronics rather than requiring ultra-fast detection capabilities

Inventive Principle:
Principle #19Periodic action

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 reduces the complexity and cost of electronic components, increases dynamic range, and optimizes signal-to-noise ratio, enabling accurate distance measurement across various ranges with reduced chip area and optical adjustment requirements.

Implementation Method 1

The returning light reflected or scattered by the aimed target object is at least partially detected by the device

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

The returning light reflected or scattered by the aimed target object is at least partially detected by the device

Methodology Applied
Scientific EffectLight scattering: Scattering

Implementation Method 3

a transit time of a light pulse can be measured from emission to detection and the distance to the target object can be calculated therefrom

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 4

the intensity of a light beam can be modulated periodically over time and a phase shift between the transmitted and the detected light signal can be used to determine the transit time

Methodology Applied
Scientific EffectLight intensity modulation: Phase Modulation

Implementation Method 5

Each of the pixels has a number of light-sensitive elements that convert incident light into electrical detection signals

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentEP2475957B2Optical distance measuring device
Publication Date: 2018.02.28 ROBERT BOSCH GMBH
  • EP2475957B2 patent drawingFigure 1
  • EP2475957B2 patent drawingFigure 2
  • EP2475957B2 patent drawingFigure 3~4

AI summary

The invention relates to a measuring device (10) for optically measuring a distance to a target object (15). Said measuring device (10) comprises an emitter device (12) for emitting an optical measuring beam (13) to the target object (15), a capturing device (14) comprising a detection surface (66) for detecting an optical beam (16) returned by the target object (15) and an evaluation device (36). Said detection surface (66) has a plurality of pixels, each pixel having at least one light-sensitive element and each of the plurality of pixels is connected to the evaluation device (36). Said emitting device and the capturing device are configured in such a manner that the optical measurement beam returned by the target object simultaneously illuminates a plurality of pixels. Said evaluation device is configured in such a manner that detection signals of a plurality of pixels are guided to at least one of the plurality of distance determining devices, based on the fact that the distance determining device determines distance data which is in correlation with the distance between the measuring device and the target object. Said evaluation device is designed such that the distance between the measuring device and the target object which is to be determined is based on an evaluation of distance data, which is determined by the plurality of distance determining devices.