Projection Light Core Layout for Shorter Optical Paths

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Solution Overview

Problem

Existing projection systems have a complex optical path that increases their size, making them unsuitable for miniaturization.

Innovation Solution

A projection optical core that utilizes an optical splitting assembly with intersecting dichroic mirrors to split the light beam once into monochromatic beams, reducing the optical path length and incorporating a reflector group and image modulation modules to enhance integration and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If multiple optical components are used to split light beams in existing projection systems, then the light beam can be separated into monochromatic beams, but the optical path length increases and the system size becomes large

Engineering Contradiction:
Improveoptical path lengthVSAvoidnumber of optical components
Core Design Contradiction:
Length of moving objectVSDevice complexity

Solution Approach 1:

The patent combines multiple optical splitting functions into a single integrated optical splitting assembly. The first and second dichroic mirrors work together in one assembly to split the input light beam into blue, green, and red monochromatic beams simultaneously, eliminating the need for multiple separate optical components and reducing the overall optical path length.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses the intersecting arrangement of dichroic mirrors at different angular orientations to achieve multi-dimensional light beam splitting. The first dichroic mirror splits light into blue and yellow beams, while the second dichroic mirror further splits the yellow beam into green and red beams, utilizing spatial dimensionality to accomplish complex beam separation in a compact configuration.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of stationary object

If a compact optical path is designed to reduce projection system size, then miniaturization can be achieved, but the optical path length may be insufficient for proper light beam manipulation

Engineering Contradiction:
Improveprojection system sizeVSAvoidoptical path length
Core Design Contradiction:
Volume of stationary objectVSLength of moving object

Solution Approach 1:

The patent employs a folded optical path design where the light beam undergoes multiple reflections between mirrors and passes through the optical splitting assembly in a compact three-dimensional arrangement. The optical path is folded back on itself, allowing sufficient interaction length for beam splitting while maintaining a small overall system volume.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The optical components are arranged in a nested configuration where the optical splitting assembly is positioned within the folded optical path, and mirrors are arranged to reflect beams through the assembly multiple times in a compact space, effectively nesting optical functions within a small volume.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 solution effectively reduces the size of the projection system while improving integration and imaging quality by minimizing the optical path length and enhancing the purity and polarization of the light beams.

Implementation Method 1

The optical splitting assembly includes a first dichroic mirror and a second dichroic mirror

Methodology Applied
Scientific EffectDichroic reflection: Dichroic Filter

Implementation Method 2

the reflector group is configured to reflect the projection light beam to the image modulation module

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 3

the reflector group is configured to reflect the projection light beam to the image modulation module

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4726469A1Projection light core, projection system, and related device
Publication Date: 2026.04.15 HUAWEI TECH CO LTD
  • EP4726469A1 patent drawingFigure 1
  • EP4726469A1 patent drawingFigure 2a
  • EP4726469A1 patent drawingFigure 2b

AI summary

A projection optical core, a projection system, and a related device are provided, which can reduce a length of an optical path of the projection optical core, thereby reducing a size of the projection optical core and improving integration of the projection optical core. The projection optical core includes an optical splitting assembly, a reflector group, and an image modulation module. The optical splitting assembly includes a first dichroic mirror and a second dichroic mirror, and the first dichroic mirror intersects with the second dichroic mirror. The optical splitting assembly is configured to split an input light beam to obtain a projection light beam. The projection light beam includes a blue light beam, a green light beam, and a red light beam. The reflector group is configured to reflect the projection light beam to the image modulation module, the optical splitting assembly intersects with a reference plane, there is a first angle between a transmission direction of the input light beam and the reference plane, there is a second angle between the reference plane and a transmission direction of the projection light beam emerging from the reflector group, and an absolute value of the first angle is less than an absolute value of the second angle. The image modulation module is configured to modulate the projection light beam to obtain an imaging light beam.