Optical Wedge Collimator Using Folded Light Path

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Solution Overview

Problem

Conventional optical collimators require a significant volume of space between the light source and the surface from which collimated light exits, making them inconveniently large for certain applications.

Innovation Solution

The use of wedge-shaped light guides, or optical wedges, which employ a folded optical path to allow light to fan out before collimation, reducing the necessary volume and enabling a more compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional optical collimators are used, then effective collimation is achieved, but the device volume increases

Engineering Contradiction:
Improvecollimation effectivenessVSAvoiddevice volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent introduces a folded optical path that utilizes the third dimension (depth) to fold the light path back on itself. This allows the optical path length to be extended in a compact footprint by using vertical space and reflective surfaces, effectively reducing the horizontal volume required while maintaining the necessary optical path length for collimation

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

Solution Approach 2:

The optical components are nested within a compact housing structure where the folded optical path allows light to travel through a compressed sequence of reflections. The optical wedge and reflective surfaces are arranged in a nested configuration that maximizes the optical path length within minimal physical space

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

This approach allows for a reduction in the size of the optical device while maintaining effective collimation, suitable for applications such as backlights for liquid crystal displays and other spatial light modulators, enabling efficient projection and detection of images.

Implementation Method 1

An optical wedge is a light guide that conducts light between one light interface at an end of the wedge and another light interface at a face of the wedge via total internal reflection

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP2467749B1Efficient collimation of light with optical wedge
Publication Date: 2017.12.13 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP2467749B1 patent drawingFigure 1
  • EP2467749B1 patent drawingFigure 2
  • EP2467749B1 patent drawingFigure 3~5

AI summary

Embodiments of optical collimators are disclosed. For example, one disclosed embodiment comprises an optical waveguide having a first end, a second end opposing the first end, a viewing surface extending at least partially between the first end and the second end, and a back surface opposing the viewing surface. The viewing surface comprises a first critical angle of internal reflection, and the back surface is configured to be reflective at the first critical angle of internal reflection. Further, an end reflector is disposed at the second end of the optical waveguide, and includes a faceted lens structure to cause a majority of the viewing surface to be uniformly illuminated when uniform light is injected into the first end and also to cause a majority of the injected light to exit the viewing surface.