Optical Image Projection Layout Without Beam Splitter Light Loss

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Solution Overview

Problem

The existing HMD device uses 50 to 50 beam splitters, resulting in a total light amount of light beam groups incident on the camera being equal to or smaller than half of that incident on the combiner optic, leading to light loss.

Innovation Solution

An optical system with first and second reflective surface groups, each with a concave shape, allows light beam groups to form overlapping images on an imaging plane, using a prism integrated with light guides to minimize light loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If 50 to 50 beam splitters are used in the combiner optic, then the optical system can reflect and transmit light beam groups, but the total light amount incident on the camera is reduced to half or less

Engineering Contradiction:

Improveoptical combining functionVSAvoidlight amount

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The optical system is divided into separate first and second optical systems, each handling one light beam group independently. This segmentation eliminates the need for a single beam splitter that divides light between multiple paths, thereby reducing light loss while maintaining the optical combining function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The reflective surfaces with concave shapes serve multiple functions: they reflect light beam groups, focus light onto the imaging plane, and enable optical combining without requiring beam splitters. This multi-functionality resolves the contradiction by achieving optical combining while preserving light amount.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple beam splitters are used to combine light beam groups, then the optical system can form images on the imaging plane, but light loss increases significantly

Engineering Contradiction:

Improveimage formation accuracyVSAvoidlight beam group intensity

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The patent replaces the mechanical beam splitter system with an optical system using reflective surfaces. This substitution eliminates the inherent light loss associated with beam splitters while maintaining the ability to form accurate images on the imaging plane.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The reflective surfaces are designed with concave shapes (curved surfaces) rather than flat surfaces. This curvature enables the surfaces to focus light beam groups effectively onto the imaging plane, achieving accurate image formation without the need for multiple beam splitters and their associated light loss.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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

Reduces light loss on the imaging plane by eliminating the need for half mirrors, ensuring efficient light beam group incidence.

Implementation Method 1

a first reflective surface group which reflects the first light beam group to allow the first light beam group to be incident on the imaging plane

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

a second reflective surface group which reflects the second light beam group to allow the second light beam group to be incident on the imaging plane

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

includes at least a first reflective surface with a concave shape... includes at least a second reflective surface with a concave shape

Methodology Applied

Scientific EffectFocusing: Focusing

Data Source

PatentUS20250355258A1Optical system, image projection device, and display position detection device

Publication Date: 2025.11.20 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

An optical system includes: a first optical system for allowing a first light beam group to form a first formation image on an imaging plane; and a second optical system for allowing a second light beam group to form a second formation image on the imaging plane. The first optical system includes a first reflective surface group which reflects the first light beam group to allow the first light beam group to be incident on the imaging plane and includes a first reflective surface with a concave shape. The second optical system includes a second reflective surface group which reflects the second light beam group to allow the second light beam group to be incident on the imaging plane and includes a second reflective surface with a concave shape. The first formation image and the second formation image overlap each other within the imaging plane.