Polygonal Prism Cavity Projection Apparatus for Wide Field of View

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Solution Overview

Problem

Current near-eye light field display technologies, such as DLP and MEMS systems, face limitations in projection field of view due to small digital micromirror device sizes, leading to high costs and difficult assembly requirements, which restrict the viewing angle and increase implementation costs.

Innovation Solution

A projection apparatus with a polygonal prism projection cavity, a scanning motor, and a reflection layer that performs rotary scanning, enhancing the projection angle of view through a convex reflective surface and diffusion layer, allowing for larger scanning ranges and improved image clarity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the size of digital micromirror device (DMD) is increased to enlarge projection FOV, then projection FOV is improved, but manufacturing difficulty and cost increase significantly

Engineering Contradiction:
Improveprojection FOVVSAvoidmanufacturing difficulty
Core Design Contradiction:
Area of stationary objectVSEase of manufacture

Solution Approach 1:

The patent transitions from a flat mirror surface to a three-dimensional polygonal prism cavity structure. The light source moves within the cavity and reflects off the inner walls, utilizing spatial dimensionality to achieve a wider projection FOV without requiring a larger flat DMD surface. This dimensional transformation allows the system to overcome the manufacturing limitations of large-size DMDs.

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

Solution Approach 2:

The patent divides the projection cavity into multiple polygonal surfaces (inner walls) that can independently reflect light. Instead of relying on a single large mirror, the system segments the reflection function across multiple smaller surfaces, making the system more manufacturable while achieving a larger effective projection area through the cumulative effect of multiple reflections.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the maximum rotation angle of the mirror is increased to enlarge projection FOV, then projection angle of view is improved, but the mechanical complexity and cost increase

Engineering Contradiction:
Improveprojection FOVVSAvoidmechanical complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent replaces the traditional single-axis rotation mechanism with a multi-dimensional polygonal cavity structure. Instead of rotating a mirror to change the projection angle, the system uses the fixed geometric configuration of the polygonal prism cavity to provide multiple reflection paths, achieving a wider projection FOV without increasing mechanical rotation complexity.

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

Solution Approach 2:

The patent substitutes the mechanical rotation system with an optical path design based on the polygonal cavity geometry. The light source's movement and reflection off the stationary polygonal surfaces replace the need for large-angle mirror rotation, reducing mechanical complexity while maintaining or improving projection capabilities.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Area of stationary object

If fiber scanning with micro motor is used to achieve large projection angle of view, then projection FOV is improved, but assembly requirements and implementation costs increase

Engineering Contradiction:
Improveprojection FOVVSAvoidassembly requirements
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent extracts the scanning function from the mechanical micro motor system and integrates it into the optical cavity design. By using the light source's movement within the polygonal cavity and the cavity's geometric properties, the system achieves scanning functionality without requiring a separate micro motor and optical fiber assembly, thereby reducing assembly complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the scanning mechanism with the projection cavity structure itself. The polygonal prism cavity serves both as the projection chamber and as the scanning element, eliminating the need for separate scanning components like micro motors and optical fibers, thus reducing assembly requirements and implementation costs.

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

The solution achieves a larger projection angle of view, enhancing the display effect and meeting user viewing requirements while reducing costs by utilizing a more efficient and cost-effective design.

Implementation Method 1

a convex reflective surface

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

diffusion layer

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3270223B1Projection apparatus and method
Publication Date: 2023.04.05 HUAWEI TECH CO LTD
  • EP3270223B1 patent drawingFigure 1~2
  • EP3270223B1 patent drawingFigure 3~4

AI summary

Embodiments of the present invention disclose a projection apparatus, including: a projection cavity, a light source, a scanning motor, and a processor. The light source and the scanning motor are located inside the projection cavity, and the processor is connected to both the light source and the scanning motor. A reflection layer is disposed on a scanning mirror of the scanning motor, where the reflection layer is configured to reflect light emitted by the light source. The embodiments of the present invention have advantages of an enlarged reflection range of light and an expanded projection angle of view.