Optical Display Assembly With Prism Light Path Alignment for AR Viewing

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Solution Overview

Problem

Intelligent wearable devices such as AR and VR glasses often suffer from the issue of users pulling the sides apart, leading to suboptimal viewing angles for projected images due to the human head's shape, which is narrow in the front and wide in the back.

Innovation Solution

The optical display assembly incorporates an optical-mechanical module, an optical transmission element, and a light path altering element, with a specific angle and positioning to ensure light projection aligns with the user's optimal viewing angle, using a light path altering element to adjust the light path and maintain a predetermined distance for optimal image viewing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the optical-mechanical module is positioned to project images, then the image can be displayed, but the user's viewing angle becomes suboptimal due to head shape

Engineering Contradiction:
Improveviewing angleVSAvoidhead shape
Core Design Contradiction:
Ease of operationVSShape

Solution Approach 1:

The patent introduces a light path altering element (prism) as an intermediary between the optical-mechanical module and the user's eye. This prism redirects the light path at a specific angle to compensate for the user's head shape and viewing position, ensuring optimal viewing angle without requiring the module to be positioned perfectly for the user's anatomical constraints

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent adjusts the light path parameters by introducing a light path altering element that changes the direction and angle of light transmission. By modifying these optical parameters, the system compensates for the fixed geometric constraints imposed by the user's head shape, enabling optimal viewing despite the narrow front and wide back proportions

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the light path is adjusted to align with optimal viewing angle, then viewing comfort improves, but the device structure becomes more complex

Engineering Contradiction:
Improveviewing angle alignmentVSAvoidoptical assembly structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent segments the optical system into distinct functional components: the optical-mechanical module for image generation, the light path altering element for angle adjustment, and the optical transmission element for light delivery. This segmentation allows each component to perform its specific function independently, making the overall complex light path adjustment manageable through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The light path altering element serves as a simple intermediary component that bridges the optical-mechanical module and the user's eye. Rather than redesigning the entire optical system, this single intermediary element handles the complex light path redirection, minimizing the increase in overall device complexity while achieving optimal viewing angle alignment

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the image is projected at a specific angle, then viewing comfort is improved, but the field of view may be obstructed

Engineering Contradiction:
Improveviewing comfortVSAvoidfield of view obstruction
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent carefully adjusts the light path parameters (angle and direction) through the light path altering element to achieve optimal viewing comfort while maintaining an open field of view. By optimizing these parameters, the system ensures that the projected image is visible and comfortable without blocking the user's natural visual field

Inventive Principle:
Principle #35Parameter changes

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 users to view projected images at optimal angles without obstructing their field of view, enhancing user experience and safety in specific scenarios by ensuring the image is visible at the correct angle without blocking vision.

Implementation Method 1

The optical transmission element is configured to receive light on the first surface and reflect the light in an interior between the first surface and the second surface

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

The light path altering element is configured to receive the light and cast the light onto the first surface

Methodology Applied
Scientific EffectRefraction: Refraction

Data Source

PatentEP4134729B1Optical display assembly and intelligent wearable device
Publication Date: 2026.03.04 GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP LTD
  • EP4134729B1 patent drawingFigure 1
  • EP4134729B1 patent drawingFigure 2
  • EP4134729B1 patent drawingFigure 3

AI summary

Provided are an optical display assembly (100) and an intelligent wearable device (1000). The optical display assembly (100) includes an optical-mechanical module (10), an optical transmission element (20), and a light path altering element (30). The optical-mechanical module (10) is configured to cast light for projecting an image. The optical transmission element (20) includes a first surface (21), a second surface (23) opposite to the first surface (21), and a third surface (25) connecting the first surface (21) with the second surface (23). The optical transmission element (21) is configured to receive the light on the first surface (21) and reflect the light in an interior between the first surface (21) and the second surface (23). The first surface (21) is at a first angle (γ) with respect to a light-emitting surface (11) of the optical-mechanical module (10). The light path altering element (30) is disposed between the optical transmission element (20) and the optical-mechanical module (10) and configured to receive the light and cast the light onto the first surface (21). The light exits the first surface (21). A distance between the third surface (25) and a center of a position at which the light exits the first surface (21) is within a predetermined range.