Laser Projection Module Temperature Drift Control

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Solution Overview

Problem

The high temperature generated by the laser emitter during operation leads to temperature drift, affecting its performance and causing inaccuracies in depth image acquisition due to excessive heat, which existing technologies have not adequately addressed.

Innovation Solution

A laser projection module that includes a temperature detection element adjacent to the laser emitter to monitor and adjust its power, reducing heat generation and minimizing performance degradation by incorporating a collimation element, diffractive optical element, and a substrate assembly with specific hole configurations for efficient temperature detection and heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the laser emitter operates at high power, then the projection brightness and depth image quality are improved, but the temperature drift increases affecting performance

Engineering Contradiction:
Improveprojection brightnessVSAvoidlaser emitter temperature
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The patent implements a feedback mechanism where a temperature detection element continuously monitors the laser emitter's temperature and sends signals to the control circuit, which adjusts the driving current in real-time to maintain stable operation and prevent temperature drift

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The control circuit dynamically adjusts the driving current parameter based on temperature feedback, changing the electrical input to the laser emitter to compensate for temperature-induced performance variations and maintain consistent projection brightness

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the laser emitter generates excessive heat, then the temperature drift affects depth image acquisition accuracy, but reducing power decreases projection brightness

Engineering Contradiction:
Improvedepth image acquisition accuracyVSAvoidlaser emitter temperature
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

The temperature detection element provides continuous temperature feedback to the control circuit, enabling real-time adjustment of driving current to maintain the laser emitter within an optimal temperature range for accurate depth image acquisition

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent proactively prevents temperature drift by implementing preemptive temperature monitoring and control, adjusting the driving current before excessive temperature rise occurs to maintain measurement precision

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Measurement precision

If the temperature detection element is placed close to the laser emitter, then temperature detection accuracy is improved, but the detection element is exposed to excessive heat

Engineering Contradiction:
Improvetemperature detection accuracyVSAvoidheat exposure to detection element
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a heat dissipation structure as an intermediary between the laser emitter and the temperature detection element, allowing the detector to remain close enough for accurate measurement while the heat dissipation structure shields it from excessive heat exposure

Inventive Principle:
Principle #24Intermediary (Mediator)

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 effectively reduces heat-related performance issues in the laser emitter, enhancing the accuracy of depth image acquisition by maintaining optimal operating temperatures and preventing temperature drift, thus improving the reliability of the laser projection module.

Implementation Method 1

a temperature detection element (50) arranged adjacent to the laser emitter (10)

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a collimation element (20) configured to collimate the laser emission

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

a diffractive optical element (30) configured to diffract the laser collimated by the collimation element (20) to form a laser pattern

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP3540877B1Laser projection module, depth camera and electronic device
Publication Date: 2022.12.21 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP3540877B1 patent drawingFigure 1~2
  • EP3540877B1 patent drawingFigure 3~4
  • EP3540877B1 patent drawingFigure 5~6

AI summary

A laser projection module, a depth camera and an electronic device are provided. The laser projection module includes a laser emitter, a collimation element, a diffractive optical element and a temperature detection element. The laser emitter is configured to emit laser. The collimation element is arranged in a laser emission direction of the laser emitter and configured to collimate the laser. The diffractive optical element is arranged in a position subsequent to the collimation element along the laser emission direction of the laser emitter, and configured to diffract the laser collimated by the collimation element to form a laser pattern. The temperature detection element is arranged adjacent to the laser emitter and configured to detect a temperature of the laser emitter.