Optical System with Symmetric Film Elements for Miniaturization

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Solution Overview

Problem

Existing optical systems face challenges in miniaturization, high manufacturing costs, and insufficient positive power due to issues with attaching film-shaped reflective linear polarizers to convex lens surfaces, such as air bubbles and wrinkles, which reduce yield and increase costs.

Innovation Solution

The optical system incorporates a half mirror and symmetrically disposed film-shaped optical elements with reflective polarizers and quarter wavelength plates attached to flat lens surfaces, allowing for a compact design with increased positive power and reduced manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a reflective linear polarizer is attached to a convex lens surface, then the optical element can be miniaturized, but manufacturing cost increases and yield decreases due to air bubbles and wrinkles

Engineering Contradiction:

Improveoptical element sizeVSAvoidmanufacturing cost

Core Design Contradiction:

Volume of moving objectVSEase of manufacture

Solution Approach 1:

The patent divides the optical element into separate components: a lens with a flat surface and a reflective linear polarizer as distinct attachable elements. This segmentation allows the polarizer to be attached to a flat surface rather than a convex surface, eliminating the need for complex attaching apparatus and reducing manufacturing difficulty while maintaining miniaturization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of attaching the reflective linear polarizer to a convex lens surface as in conventional designs, the patent inverts the approach by attaching it to a flat lens surface. This inversion resolves the manufacturing issues of air bubbles and wrinkles while preserving the miniaturized optical element design.

Inventive Principle:

Principle #13The other way round (Inversion)

2Volume of moving object

If a reflective linear polarizer is attached to a convex lens surface, then the optical element can be miniaturized, but yield decreases due to air bubbles and wrinkles

Engineering Contradiction:

Improveoptical element sizeVSAvoidyield

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

By segmenting the optical element into a lens and a separate reflective linear polarizer that can be attached to a flat surface, the patent eliminates the reliability issues of air bubbles and wrinkles that occur when attaching to convex surfaces, thereby improving yield while maintaining miniaturization.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent inverts the conventional approach of attaching the polarizer to a convex surface and instead attaches it to a flat surface. This inversion eliminates the harmful effects of air bubbles and wrinkles, improving yield without sacrificing the miniaturized design.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of manufacture

If a reflective linear polarizer is attached to a flat lens surface, then manufacturing cost decreases, but positive power of the optical element becomes insufficient

Engineering Contradiction:

Improvemanufacturing costVSAvoidpositive power

Core Design Contradiction:

Ease of manufactureVSPower

Solution Approach 1:

The patent merges the functions of the lens and the reflective linear polarizer into a single integrated optical element where the polarizer is attached to a flat surface of the lens. This combination maintains ease of manufacture while the lens design compensates to provide sufficient positive power, resolving the contradiction between manufacturing simplicity and optical performance.

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

This configuration enables a miniaturized optical system with enhanced positive power and reduced manufacturing costs, while avoiding issues like air bubbles and wrinkles, thus improving yield and efficiency.

Implementation Method 1

first linearly-polarized light passes through a first reflective linear polarizer and passes through a first phase difference plate to be changed into right handed circularly-polarized light

Methodology Applied

Scientific EffectPhase difference:

Implementation Method 2

Part of the right handed circularly-polarized light is reflected by a partial reflection mirror to be changed into left handed circularly-polarized light

Methodology Applied

Scientific EffectPartial reflection: Reflection

Implementation Method 3

second circularly-polarized light having the second rotation direction being emitted from the third surface; second linearly-polarized light having a second polarization direction perpendicular to the first polarization direction being emitted from the sixth surface

Methodology Applied

Scientific EffectPolarization transformation: Polarisation

Data Source

PatentUS20250138293A1Optical system, display device, and head-mounted device

Publication Date: 2025.05.01 SHARP DISPLAY TECHNOLOGY CORP

AI summary

An optical system includes a half mirror; a first at least one optical element including a first film-shaped optical element to be attached to a first plane; a second at least one optical element including a second film-shaped optical element to be attached to a second plane, disposed at a position symmetric to a position at which the first at least one optical element is disposed with respect to the half mirror, and having a shape symmetric to a shape of the first at least one optical element with respect to the half mirror; and a convex lens.