Light Source Module Phosphor Wheel Drive Stray Light Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing light source modules in image projection apparatuses face issues with stray light due to diffused fluorescence, which reduces the effectiveness of the light emitted from the phosphor layer and leads to noise such as flare in the projection image.

Innovation Solution

A light source module with a phosphor wheel having a drive section on the phosphor-layer side, where the drive section is configured to rotate the phosphor wheel and includes a light shielding unit comprising a side plate and a drive section to minimize stray light by positioning the drive section on the surface with the phosphor layer, and integrating the lens barrel, side plate, and holder as a single unit to control the distance and improve condensing efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If the phosphor layer is laid on a rotatable phosphor wheel and irradiated with excitation light, then fluorescence is emitted for use in the light source module, but diffused light becomes stray light reducing light effectiveness

Engineering Contradiction:

Improvelight effectivenessVSAvoidstray light

Core Design Contradiction:

Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful diffused light into beneficial directed light by positioning the drive section on the phosphor-layer side to block stray light while the phosphor wheel rotation maintains uniform illumination. The drive section acts as a light shield that transforms potential stray light paths into controlled illumination paths.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent applies local quality by providing the phosphor layer in a recess formed on the phosphor wheel surface at a specific location, rather than uniformly across the entire surface. This localized positioning reduces diffused light in unwanted directions while maintaining effective illumination where needed.

Inventive Principle:

Principle #3Local quality

2Object-generated harmful factors

If the drive section is positioned on the phosphor-layer side of the phosphor wheel, then stray light is reduced, but the structure becomes more complex

Engineering Contradiction:

Improvestray light reductionVSAvoidstructure complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the drive section with the phosphor wheel structure by positioning it on the phosphor-layer side and integrating it with the rotation mechanism. This combination eliminates the need for separate light shielding components, reducing overall structural complexity while maintaining stray light reduction functionality.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The drive section serves multiple functions: it rotates the phosphor wheel to maintain uniform illumination and simultaneously acts as a light shield to block stray light. This multi-functionality reduces the need for additional components, simplifying the overall structure while addressing both illumination uniformity and stray light reduction.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Length of moving object

If the light source module length is minimized for downsizing, then the module becomes more compact, but condensing efficiency may be reduced

Engineering Contradiction:

Improvemodule lengthVSAvoidcondensing efficiency

Core Design Contradiction:

Length of moving objectVSProductivity

Solution Approach 1:

The patent addresses the length-efficiency contradiction by utilizing the radial dimension of the phosphor wheel structure. The phosphor layer is positioned in a recess on the wheel surface, allowing light condensing to occur in the radial direction rather than extending the module length axially. This dimensional change maintains condensing efficiency while minimizing overall module length.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs nesting by placing the phosphor layer within a recess formed on the phosphor wheel surface. This nested configuration allows the light condensing structure to be embedded within the wheel itself, eliminating the need for extended external condensing components and reducing the overall module length while maintaining condensing efficiency.

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 stray light, prevents noise like flare in the projection image, and allows for a downsized light source module by minimizing the length of the light source module, while maintaining high fluorescence condensing efficiency and brightness.

Implementation Method 1

a phosphor wheel having a phosphor layer to emit fluorescence when excited with light emitted from a light source

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Data Source

PatentUS10996458B2Light source module, optical device, and method for producing light source module

Publication Date: 2021.05.04 RICOH CO LTD

AI summary

A light source module including a phosphor wheel having a phosphor layer to emit fluorescence when excited with light emitted from a light source; and a drive section disposed on a phosphor-layer side of the phosphor wheel, the drive section configured to rotate the phosphor wheel.