Laser Projection Module Stepped Housing for Full-Screen Depth Sensing

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Solution Overview

Problem

Current mobile phone designs with structured light schemes are limited by the volume of the structured light unit and the immaturity of under-screen structured light technology, resulting in a low screen-to-body ratio and a large occupied area on the front panel, hindering the realization of a full screen.

Innovation Solution

A laser projection unit with a housing and diffraction element design that includes a stepped face and notches to mount the display screen, allowing the laser projection unit to occupy a small area on the front panel while improving the screen-to-body ratio, and incorporating a depth camera with a laser projection unit and imaging unit to project and receive laser for depth information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional structured light unit is used in mobile phone design, then depth measurement function is achieved, but the screen-to-body ratio is reduced and front panel area is occupied

Engineering Contradiction:
Improvedepth measurement functionVSAvoidfront panel occupied area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent integrates the laser projection unit and imaging unit within a compact housing structure where components are nested together. The laser emitter, collimating element, diffractive optical element, and imaging sensor are arranged in a nested configuration that minimizes the overall footprint on the front panel while maintaining full depth measurement functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a planar arrangement of depth sensing components to a three-dimensional stacked configuration. By utilizing vertical space and arranging components along the optical axis rather than spreading them across the front panel, the design achieves compact integration that preserves screen-to-body ratio while enabling complete structured light depth measurement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If under-screen structured light technology is used, then front panel area is saved, but the technology is immature and may not provide reliable depth measurement

Engineering Contradiction:
Improvefront panel occupied areaVSAvoiddepth measurement function
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent divides the depth measurement system into distinct functional modules: a laser projection unit with separate optical elements (collimating element, diffractive optical element) and an imaging unit with sensor array. This segmentation allows each component to be optimized for its specific function, ensuring reliable depth measurement while maintaining compact form factor suitable for mobile device integration.

Inventive Principle:
Principle #1Segmentation

3Area of stationary object

If laser projection unit components are made compact, then screen-to-body ratio is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvefront panel occupied areaVSAvoidcomponent alignment precision
Core Design Contradiction:
Area of stationary objectVSManufacturing precision

Solution Approach 1:

The patent combines multiple optical elements (laser emitter, collimating element, diffractive optical element) and the imaging sensor into a single integrated housing structure. This merging approach establishes fixed spatial relationships between components, reducing the need for high-precision manual alignment during assembly while maintaining compact dimensions that improve screen-to-body ratio.

Inventive Principle:
Principle #5Merging (Combining)

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 design enhances the screen-to-body ratio by minimizing the area occupied by the depth camera and laser projection unit, enabling a full-screen display on mobile devices.

Implementation Method 1

a laser projection unit with housing and diffraction element

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 2

The laser projection unit is used to project a laser outwards

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 3

The imaging unit is used to receive a reflected laser

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3975525B1Laser projection module, depth camera and electronic device
Publication Date: 2023.10.25 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP3975525B1 patent drawingFigure 1
  • EP3975525B1 patent drawingFigure 2a~2b
  • EP3975525B1 patent drawingFigure 3

AI summary

A laser projection module (10), a depth camera (100), and an electronic device (1000) are provided. The laser projection module includes a housing (12) and a diffraction element (14). The housing (12) includes a first sub-housing (121) and a second sub-housing (122). The first sub-housing (121) includes a top face (123) coupled to the second sub-housing (122). The second sub-housing (122) includes a side face (124), and the side face and the top face (123) cooperatively form a stepped face and define a first notch (21). The diffraction element (14) is mounted in the second sub-housing (122).