Light Source Apparatus Phosphor Wheel Mount Angles

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Solution Overview

Problem

Existing light source apparatuses for time divisional projectors face issues with high light intensity at the condensed point, leading to reduced phosphor emission efficiency due to the small diameter of the light condensed position, which can be exacerbated by the need for precise adjustments and high productivity concerns.

Innovation Solution

The light source apparatus varies the mount angles of housings with respect to the supporting member and shifts the collimating lens position relative to the laser diode, allowing lights to be condensed onto different positions on the phosphor wheel, thereby lowering light intensity and density, and simplifying assembly while maintaining high emission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the light from laser light sources is condensed onto the same position on the phosphor, then the brightness uniformity can be improved, but the light intensity at the condensed point becomes too high, reducing phosphor emission efficiency

Engineering Contradiction:
Improvebrightness uniformityVSAvoidphosphor emission efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent divides the single condensed position into multiple condensed positions by introducing multiple laser light sources (first and second laser light sources) that condense light onto different locations on the phosphor. This segmentation distributes the light intensity across multiple points, preventing excessive concentration at one location while maintaining overall brightness uniformity through coordinated control of the multiple sources.

Inventive Principle:
Principle #1Segmentation

2Illumination intensity

If the diameter of the light condensed position is made small, then the brightness intensity can be increased, but the phosphor emission efficiency is reduced due to high light intensity

Engineering Contradiction:
Improvebrightness intensityVSAvoidphosphor emission efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent transitions from concentrating light in a single point (zero-dimensional) to distributing light across multiple positions (spatial distribution in two dimensions). By using multiple laser light sources that condense onto different locations on the phosphor, the system maintains high brightness intensity through the combined output of multiple sources while avoiding excessive intensity at any single point, thus preserving phosphor emission efficiency.

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

3Illumination intensity

If the laser light source is rotated around its optical axis to enlarge the light shape, then the brightness uniformity can be improved, but the rotating direction of each laser diode needs to be adjusted, increasing device complexity

Engineering Contradiction:
Improvebrightness uniformityVSAvoidadjustment complexity
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

Instead of rotating a single laser light source around its optical axis, the patent segments the light source into multiple stationary laser diodes (first and second laser light sources) positioned at different locations. This eliminates the need for rotational adjustment mechanisms while achieving brightness uniformity through the spatial distribution of multiple fixed sources, each emitting in a predetermined direction.

Inventive Principle:
Principle #1Segmentation

4Device complexity

If the light condensed position is kept at the same location for all laser sources, then the optical path can be simplified, but the light intensity becomes too high, reducing phosphor emission efficiency

Engineering Contradiction:
Improveoptical path simplicityVSAvoidphosphor emission efficiency
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The patent applies local quality by assigning different condensed positions to different laser light sources on the phosphor. Each laser source (first and second) has its light condensed onto a specific location, creating localized light intensity distributions that collectively cover the phosphor surface. This approach maintains relatively simple optical paths for each individual source while ensuring that no single location receives excessive light intensity, thereby preserving phosphor emission efficiency.

Inventive Principle:
Principle #3Local quality

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 reduces light density at the condensed point, enhancing phosphor emission efficiency and maintaining productivity by allowing for simple assembly and reduced component complexity.

Implementation Method 1

lights emitted from the plurality of housings are condensed onto different positions on the phosphor wheel by the condenser lens

Methodology Applied
Scientific EffectLight condensation: Focusing

Implementation Method 2

convert wavelength of a blue light from a laser diode into that of a green or red light by using phosphors

Methodology Applied
Scientific EffectPhosphor emission: Photoluminescence

Data Source

PatentEP2990869B1Light source apparatus and projector having light source apparatus
Publication Date: 2018.03.21 NICHIA CORP
  • EP2990869B1 patent drawingFigure 1A~1B
  • EP2990869B1 patent drawingFigure 2A~2C
  • EP2990869B1 patent drawingFigure 3A~3C

AI summary

A light source apparatus (1) and a projector (100) including the light source apparatus are provided. The light source apparatus (1) comprises: a plurality of light sources each source including a laser diode (12) and a collimating lens (13), said collimating lens (13) collimates a light emitted from said laser diode (12) into an approximately collimated beam, a plurality of housings (10) in which said plurality of light sources are placed so that a light is emitted from each of said light source advances approximately in parallel in the same direction, a condenser lens (20) which condenses lights which is emitted from said plurality of housings (10) to a phosphor (32), a phosphor wheel (30) having said phosphor (32), said phosphor wheel (30) transmitting the lights which is emitted from said condenser lens (20), wherein incident angles of the lights emitted from said housings (10) to an optical axis of said condenser lens (20) are made different by varying mount angles of said housings (10) to a supporting member (60).