Dichroic Mirror Light Synthesis for Projector Brightness

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Solution Overview

Problem

Dichroic mirrors in light source devices for projectors suffer from poor transmittance and reflectance, leading to light loss and a resulting dark image projection due to their properties, which affect the optical efficiency when synthesizing light of different wavelengths.

Innovation Solution

A light source device comprising a first light source emitting excitation light, a second light source emitting light of a first wavelength, a third light source emitting light of a second wavelength, a fluorescent material generating light of a third wavelength, and a dichroic mirror that transmits the first wavelength and reflects the third wavelength, with the dichroic mirror positioned to allow the second wavelength to pass outside without entering, thereby reducing light loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a dichroic mirror is used to synthesize light of different wavelengths, then light synthesis capability is improved, but light loss increases and optical efficiency deteriorates

Engineering Contradiction:

Improvelight synthesis capabilityVSAvoidlight loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent divides the light synthesis function into two separate paths: one path uses the dichroic mirror for wavelengths requiring filtering, while another path allows specific wavelengths to pass outside the dichroic mirror. This segmentation reduces the number of times light interacts with the dichroic mirror, minimizing light loss while maintaining synthesis capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a beam splitter as an intermediary component to separate and redirect specific wavelengths before they reach the dichroic mirror. This intermediary allows certain light paths to bypass the dichroic mirror entirely, reducing light loss while still enabling wavelength synthesis through coordinated optical paths.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a dichroic mirror is used to transmit and reflect light of different wavelengths, then wavelength separation capability is improved, but transmittance and reflectance performance deteriorate

Engineering Contradiction:

Improvewavelength separation capabilityVSAvoidtransmittance and reflectance

Core Design Contradiction:

Adaptability or versatilityVSIllumination intensity

Solution Approach 1:

The optical system is segmented into multiple paths where different wavelength ranges are handled differently. Some wavelengths are separated by the dichroic mirror, while others bypass it entirely, avoiding the inherent transmittance and reflectance losses of the dichroic film while maintaining wavelength separation capability.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If light is transmitted and reflected multiple times by the dichroic mirror, then light synthesis flexibility is improved, but optical efficiency deteriorates

Engineering Contradiction:

Improvelight synthesis flexibilityVSAvoidoptical efficiency

Core Design Contradiction:

Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent segments the light synthesis process into direct paths and reflected paths. By allowing certain wavelengths to travel directly outside the dichroic mirror rather than being transmitted or reflected multiple times, the system maintains synthesis flexibility while significantly reducing the number of optical interactions and improving overall efficiency.

Inventive Principle:

Principle #1Segmentation

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 enhances light utilization by minimizing light loss through the dichroic mirror, resulting in a brighter image projection by ensuring that at least part of the light is synthesized without being transmitted through the dichroic mirror, thus improving the projector's brightness and image quality.

Implementation Method 1

a fluorescent material which receives the excitation light from the first light source to emit generated light of a third wavelength bandwidth different from the first and second wavelength bandwidths

Methodology Applied

Scientific EffectFluorescence: Fluorescence

Implementation Method 2

a dichroic mirror which transmits the light of the first wavelength bandwidth and reflects the light of the third wavelength bandwidth

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 3

a dichroic mirror which can transmit or reflect an arbitrary wavelength, to synthesize the blue light, the green light and the red light from the respective light sources on one image display device

Methodology Applied

Scientific EffectDichroic filter effect: Dichroic Filter

Data Source

PatentUS9194560B2Light source device and projector

Publication Date: 2015.11.24 CASIO COMPUTER CO LTD

AI summary

A light source device includes first to third light sources, a fluorescent material, and a dichroic mirror. The dichroic mirror is constituted so that excitation light emitted from the first light source is transmitted through the dichroic mirror and applied to the fluorescent material, light of a first wavelength bandwidth emitted from the second light source is transmitted through the dichroic mirror and emitted in a predetermined emitting direction, generated light emitted from the fluorescent material is reflected by the dichroic mirror and emitted in the predetermined emitting direction, and at least a part of light of a second wavelength bandwidth from the third light source passes the outside of the dichroic mirror without entering the dichroic mirror, and is emitted in the predetermined emitting direction.