Color Sequential Light Source for Projectors

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Solution Overview

Problem

Conventional projectors that temporarily irradiate blue, red, and green light onto an image-forming element to create color images have complex manufacturing processes due to the need for separate fluorescence areas and angle configurations in the phosphor, leading to complicated control and layout requirements.

Innovation Solution

A light source device with a single light source section that generates color images without separating the phosphor's fluorescence areas, using a light path-switching disk and a color-changing disk to control the irradiation of blue, green, and red light, allowing for simplified manufacturing and layout freedom.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the phosphor is configured with separate fluorescence areas and transmitting areas with different angle sizes, then the projector can generate color images with proper light paths, but the manufacturing process becomes complicated and control becomes difficult

Engineering Contradiction:
Improvecolor image generation capabilityVSAvoidphosphor manufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the phosphor into multiple fluorescence areas (first fluorescence area, second fluorescence area, third fluorescence area) with different tilt angles, and corresponds each area with a dedicated light source (first light source, second light source, third light source). This segmentation allows independent control of each fluorescence region while simplifying the overall manufacturing process by avoiding the need for complex angle-matched transmitting areas.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the phosphor is configured with separate fluorescence areas and transmitting areas, then the light paths can be controlled, but the layout freedom of the optical system is reduced

Engineering Contradiction:
Improvelight path controlVSAvoidoptical system layout freedom
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent introduces a rotatable color-changing disk that dynamically switches between different transmitting areas (first transmitting area, second transmitting area, third transmitting area) with different color transmission characteristics. This dynamic element provides flexibility in light path control while maintaining layout freedom, as the disk can be rotated to different angles to achieve various optical configurations without redesigning the static phosphor structure.

Inventive Principle:
Principle #15Dynamics

3Reliability

If multiple fluorescence areas with different angles are formed on the phosphor, then color image generation is achieved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvecolor image qualityVSAvoidphosphor angle control precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent segments the phosphor into distinct fluorescence areas with specific tilt angles (first fluorescence area with first tilt angle, second fluorescence area with second tilt angle, third fluorescence area with third tilt angle), and pairs each with a dedicated light source. This segmentation approach simplifies manufacturing precision requirements by allowing each area to be optimized independently rather than requiring precise angular control across the entire phosphor surface.

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

Simplifies the manufacturing process of the phosphor and optical system, improving layout flexibility and reducing the complexity of controlling the light source, while maintaining the ability to form color images effectively.

Implementation Method 1

a phosphor configured to generate red fluorescent light and green fluorescent light through irradiation of the excitation light emitted from the light source section

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Implementation Method 2

a color-changing section comprising a rotatable color-changing disk comprising: a first transmitting area configured to transmit blue color light and block the transmission of red and green fluorescent light

Methodology Applied
Scientific EffectSelective light transmission and absorption: Absorption (EM radiation)

Data Source

PatentEP3703364B1Color sequential light source for preventing color mixing and projector using the same
Publication Date: 2024.05.29 RICOH CO LTD
  • EP3703364B1 patent drawingFigure 1
  • EP3703364B1 patent drawingFigure 2~4
  • EP3703364B1 patent drawingFigure 5~6

AI summary

A light source device comprising: a light source section configured to emit excitation light (BP); a phosphor configured to generate fluorescent light (YP) through irradiation of the excitation light (BP) emitted from the light source section; and a color-changing section configured to transmit color light (W(B,Y), RP, GP) having a color different from that of the fluorescent light (YP) emitted from the phosphor, wherein an emission timing of the fluorescent light (YP) in the phosphor is synchronized with a switching timing between the excitation light (BP) and the color light (W(B,Y), RP, GP) by the color-changing section, and the light source section is configured to decrease the brightness of a projection image in the switching timing (1d, 1e) between the excitation light (BP) and the color light (W(B,Y), RP, GP) by the color-changing section.