Segmented Louver for Head-Mounted Display Light Shielding

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Solution Overview

Problem

Head-mounted displays face issues with external light interference causing image quality deterioration and high temperature and humidity accumulation, leading to discomfort and optical element degradation.

Innovation Solution

A louver is integrated into the optical path of the head-mounted display, featuring light shielding portions arranged along concentric circles or arcs, effectively blocking external light while allowing display light to pass through, thereby reducing ghosting and maintaining image quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a light-shielding member surrounds the periphery of the optical path space, then external light is blocked and image quality is improved, but heat and moisture are retained causing high temperature and high humidity

Engineering Contradiction:
Improveexternal light interferenceVSAvoidtemperature inside optical path space
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The light-shielding member is divided into multiple light shielding portions arranged in specific patterns (concentric circles, arcs, or radial lines) rather than forming a continuous enclosure. This segmentation allows light blocking in critical directions while creating gaps for thermal and moisture management

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The light-shielding member provides light shielding only in specific locations and directions where external light interference is most problematic, rather than complete surrounding shielding. The light shielding portions are strategically positioned to block ghosting while maintaining thermal ventilation paths

Inventive Principle:
Principle #3Local quality

2Object-affected harmful factors

If a light-shielding member surrounds the periphery of the optical path space, then external light is blocked and image quality is improved, but moisture accumulates causing fogging and degradation

Engineering Contradiction:
Improveexternal light interferenceVSAvoidoptical element reliability
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The continuous light-shielding enclosure is segmented into discrete light shielding portions with intentional gaps between them. These gaps serve dual purposes: blocking external light in critical directions while allowing moisture to escape and air circulation to prevent fogging

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Light shielding is applied locally only where external light interference causes image quality deterioration, rather than complete surrounding shielding. This localized approach maintains sufficient light blocking performance while preserving moisture management capabilities

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If light shielding portions are added to block external light, then image quality is improved, but device complexity increases

Engineering Contradiction:
Improveexternal light interferenceVSAvoidstructure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The light-shielding member serves multiple functions simultaneously: it blocks external light in critical directions, maintains structural integrity of the optical path space, and enables thermal and moisture management through its segmented design. This multi-functionality reduces the need for separate components

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

Solution Approach 2:

The light-shielding member is integrated with the existing optical path space structure rather than being a separate add-on component. The light shielding portions are positioned to work with the optical element and surrounding structure, combining light blocking functionality with the overall device architecture

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 louver significantly suppresses external light interference, maintaining image quality and preventing high temperature and humidity buildup, enhancing user comfort and optical element longevity.

Implementation Method 1

a louver having a light shielding property is provided below an optical path space of the display light directed to a user's eye

Methodology Applied
Scientific EffectLight shielding: Absorption (EM radiation)

Data Source

PatentEP4075172B1Head mounted display, louver, optical device, and manufacturing method of louver
Publication Date: 2024.12.18 CANON KK
  • EP4075172B1 patent drawingFigure 1
  • EP4075172B1 patent drawingFigure 2
  • EP4075172B1 patent drawingFigure 3A~3C

AI summary

A louver (23) includes light shielding portions (5) made of a light shielding material. The light shielding portions (5) are provided inside a plate-like base portion (2, 3) made of a light transmitting material. In a plan view of a main surface of the plate-like base portion, the light shielding portions (5) are arranged at a predetermined interval (P) so as to sandwich a light transmitting portion. A width (t) of each of the light shielding portions (5) is 9% or less of the predetermined interval (P) between the light shielding portions (5).