Orthogonal Parabolic Mirror for Compact Light Collimation

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Solution Overview

Problem

Existing projector systems using semiconductor lasers face challenges in light collimation due to the wide divergence angle in the slow-axis direction, requiring a long focal length collimator lens that leads to beam interference and increased projector size, making it difficult to achieve efficient light shaping without upsizing the mechanism.

Innovation Solution

A light shaping apparatus featuring a linear light source with a reflective mirror portion having an orthogonal parabolic surface that converges light emitted from the source, allowing for efficient collimation without the need for a long focal length collimator lens, thereby preventing mechanism upsizing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a collimator lens with long focal length is used to collimate light in the slow-axis direction, then light collimation efficiency is improved, but the projector size increases and beam interference occurs

Engineering Contradiction:
Improvelight collimation efficiencyVSAvoidprojector size
Core Design Contradiction:
Illumination intensityVSVolume of moving object

Solution Approach 1:

The patent divides the light shaping process into two separate stages: first shaping light in the fast-axis direction using a collimator lens, then shaping light in the slow-axis direction using a cylindrical lens. This segmentation allows each lens to have optimized parameters without requiring an excessively long focal length, thus preventing projector upsizing while maintaining collimation efficiency

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent addresses the two-dimensional divergence characteristics of semiconductor laser light by applying different optical components for each axis. The collimator lens handles the fast-axis direction while the cylindrical lens handles the slow-axis direction, effectively treating the light shaping problem in separate dimensions to avoid the need for a single long focal length lens

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

2Illumination intensity

If a collimator lens with long focal length is used to collimate light in the slow-axis direction, then light collimation efficiency is improved, but beam interference between adjacent lasers occurs

Engineering Contradiction:
Improvelight collimation efficiencyVSAvoidbeam interference
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

By segmenting the light shaping function into two separate lenses oriented perpendicular to each other, the patent enables proper spatial separation of beams from adjacent lasers. The cylindrical lens specifically addresses slow-axis divergence with appropriate beam spacing, preventing overlap and interference while achieving effective collimation

Inventive Principle:
Principle #1Segmentation

3Power

If additional laser light sources are added to enhance optical output, then projector output is improved, but manufacturing cost increases

Engineering Contradiction:
Improveoptical outputVSAvoidmanufacturing cost
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent improves optical output by optimizing the parameters of the light shaping optical system rather than adding more laser sources. By using a cylindrical lens to effectively collimate light in the slow-axis direction, the system maximizes light utilization efficiency, allowing existing lasers to operate at full potential without requiring additional expensive components

Inventive Principle:
Principle #35Parameter changes

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 effectively concentrates light from the semiconductor laser, reducing the need for additional optical components and manufacturing costs, while maintaining a compact design by aligning the light source with the reflective mirror's rotation axis, resulting in a highly homogeneous light source suitable for projector systems.

Implementation Method 1

The light emitted from the linear light source is reflected by the reflective mirror portion surrounding at least part of the linear light source, and further converges at the convergence point

Methodology Applied
Scientific EffectReflection: Reflection

Implementation Method 2

a reflective mirror portion having a reflective surface that is an orthogonal parabolic surface formed by rotating a curved line about a rotation axis

Methodology Applied
Scientific EffectParabolic surface focusing: Geometry

Data Source

PatentEP3540510B1Light shaping device
Publication Date: 2020.06.24 MITSUBISHI ELECTRIC CORP
  • EP3540510B1 patent drawingFigure 1
  • EP3540510B1 patent drawingFigure 2~3
  • EP3540510B1 patent drawingFigure 4

AI summary

Provided is a technique of shaping light emitted from a linear light source while preventing mechanism upsizing. A light shaping apparatus includes a linear light source (20) having a light-emitting point (101), a reflective mirror portion (32) having an orthogonal parabolic surface, and an optical device (40) disposed at a convergence point (200) where light (100) emitted from the linear light source converges. The light from the linear light source is reflected by the reflective mirror portion surrounding the linear light source, and further converges at the convergence point. The reflective mirror portion has a rotation axis extending along the longer-side direction of the linear light source. The light-emitting point of the linear light source is located on the rotation axis of the reflective mirror portion. The optical device has an entrance end face (41) located at the convergence point. The entrance end face is an end face on which the light from the linear light source is incident.