Phosphor Layer Regulates Blue Light Wavelength for Rec. 709
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Solution Overview
Problem
Conventional 445-nm laser projectors experience significant color shift due to their blue light source not conforming to the CIE coordinate of Rec. 709, impacting display gamut, and existing methods to adjust blue light wavelength are inefficient and costly, requiring additional filters and optical pathway modifications.
Innovation Solution
A method involving a single-color light source with a phosphor layer, where the light transmits through the phosphor layer to generate a second chromatic light with a longer wavelength, and the residual and second chromatic lights are mixed to produce a third chromatic light with a regulated wavelength, using a phosphor material like Ba1-xSi2O2N2:Eux, to adjust the blue light source's CIE coordinate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional 445-nm blue light source is used to excite phosphor, then the projector can operate with a simple optical path, but the blue light source produces significant color shift and does not conform to the CIE coordinate of Rec. 709
Solution Approach 1:
A phosphor conversion layer is introduced as an intermediary between the 445-nm blue light source and the display optical path. This layer converts a portion of the blue light to other wavelengths, enabling the system to achieve Rec. 709 compliance without modifying the original blue light source or adding complex optical components.
Solution Approach 2:
The patent changes the spectral parameters of the blue light source by using a phosphor conversion layer with specific characteristics (emission peak wavelength, quantum efficiency, thickness). By adjusting these parameters, the combined spectrum of converted and residual blue light achieves the desired CIE coordinates while maintaining optical path simplicity.
2Manufacturing precision
If additional filters and optical pathway modifications are used to adjust blue light wavelength, then color accuracy can be improved, but product cost and device complexity increase
Solution Approach 1:
Instead of using additional filters and modifying the optical pathway, the patent uses a phosphor conversion layer as a mediator that achieves color adjustment in a single location within the light source module, thereby avoiding increased device complexity.
Solution Approach 2:
The patent combines the functions of wavelength conversion and color regulation into a single phosphor conversion layer, merging multiple potential components (filters, waveplates, additional optical elements) into one integrated solution that reduces overall device complexity.
3Manufacturing precision
If additional filters and optical components are added to regulate light wavelength, then color rendering can be improved, but product cost increases
Solution Approach 1:
The phosphor conversion layer serves as a cost-effective intermediary that achieves color rendering improvement without requiring expensive additional filters and optical components, thereby reducing overall product cost.
Solution Approach 2:
By carefully selecting phosphor materials with specific emission characteristics and optimizing the conversion layer parameters, the patent achieves desired color rendering at lower cost compared to using multiple precision optical components and filters.
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 method effectively regulates the blue light source to approach the CIE coordinate of Rec. 709, enhancing color rendering without the need for additional filters or optical pathway changes, thereby reducing product costs and improving color accuracy.
Implementation Method 1
transforming a part of the first chromatic light to a second chromatic light through the phosphor layer, and emitting the residual first chromatic light, wherein the wavelength of the second chromatic light is longer than the wavelength of the first chromatic light
Data Source
AI summary
The disclosure provides a method for regulating a light wavelength of a projection device. The method comprises the following steps. A single-color light source is provided and emits a first chromatic light. A phosphor layer is formed on an optical path of the single-color light source, so that the first chromatic light transmits the phosphor layer. The phosphor layer transforms a part of the first chromatic light to a second chromatic light, and emits the residual first chromatic light. The residual first chromatic light is further mixed with the second chromatic light to generate a third chromatic light. The wavelength of the third chromatic light is regulated by adjusting the proportion of the luminous intensity of the residual first chromatic light and the second chromatic light.