Optical Module Dust-Proofing via Segmented Members

Solution Overview

Problem

Existing optical modules for head-mounted displays face challenges in achieving dust-proofing and miniaturization while maintaining effective optical performance, as increased housing size is required to accommodate dust-proofing measures, which compromises the size and efficiency of the display device.

Innovation Solution

The optical module incorporates a combination of optical members, including a projection lens, prism mirror, wedge type optical element, and see-through mirror, with a dust-proofing system that uses elastic dust-proof tape to cover gaps between components without a separate case, ensuring dust-proofing and miniaturization by covering the optical members and their interfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a housing covers the unit accommodating optical members to ensure dust-proofing, then dust-proofing is improved, but the housing size increases

Engineering Contradiction:

Improvedust-proofingVSAvoidhousing size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The dust-proofing function is segmented from the housing structure and assigned to separate dust-proof members (first dust-proof member and second dust-proof member) that selectively cover specific regions. This allows dust-proofing without requiring a complete housing enclosure, thereby reducing housing size while maintaining protection where needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dust-proofing function is extracted from the housing and implemented as independent dust-proof members positioned only where dust protection is necessary (covering optical members and their interfaces). This extraction eliminates the need for a bulky enclosing housing while preserving dust-proofing performance at critical locations.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If the unit accommodating optical members is made dust-proof, then dust-proofing is improved, but the unit size increases

Engineering Contradiction:

Improvedust-proofingVSAvoidunit size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

Dust-proofing is applied locally only to the regions containing optical members (projection lens, prism mirror, wedge type optical element) and their interfaces, rather than enclosing the entire unit. The dust-proof members are positioned to cover gaps between optical members and other components, providing targeted protection without increasing overall unit volume.

Inventive Principle:

Principle #3Local quality

3Reliability

If a housing is made dust-proof or water-proof to protect optical members, then dust-proofing is improved, but the housing size increases

Engineering Contradiction:

Improvedust-proofingVSAvoidhousing size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The dust-proofing function is segmented from the housing structure and assigned to separate dust-proof members (first dust-proof member and second dust-proof member) that selectively cover specific regions. This allows dust-proofing without requiring a complete housing enclosure, thereby reducing housing size while maintaining protection where needed.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The dust-proofing function is extracted from the housing and implemented as independent dust-proof members positioned only where dust protection is necessary (covering optical members and their interfaces). This extraction eliminates the need for a bulky enclosing housing while preserving dust-proofing performance at critical locations.

Inventive Principle:

Principle #2Taking out (Extraction)

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 allows for effective dust-proofing and miniaturization of the optical module, preventing stray light and enhancing heat dissipation, while maintaining optical performance and reducing the overall size of the head-mounted display device.

Implementation Method 1

a reflection portion that reflects the image light from the second incident portion toward the second emission portion

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

a combiner that reflects the image light from the third optical member toward a position of a pupil

Methodology Applied

Scientific EffectReflection: Reflection

Data Source

PatentUS11573425B2Optical module and head-mounted display device

Publication Date: 2023.02.07 SEIKO EPSON CORP

AI summary

An optical module includes an image element, a projection lens, a prism mirror, a wedge type optical element, a barrel configured to support the prism mirror and the wedge type optical element, a first combiner configured to deflect image light emitted from the wedge type optical element, a first dust proof member configured to cover a both end region of the projection lens, the prism mirror, and the barrel in a third axis, and cover an end region of the projection lens and the prism mirror located on the prism mirror side in a second axis, and a second dust proof member provided between the projection lens and the barrel.