3D Projection Display Synchronization for Luminance Uniformity
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Solution Overview
Problem
Spectroscopic 3D image display devices experience non-uniformity in luminance due to differences in fluorescence yield of phosphors caused by varying wavelengths of blue light emitted from light sources, affecting viewing quality.
Innovation Solution
A spectroscopic 3D image display device with two projection type image display devices, each using light sources with different central wavelengths of blue light, controlled by a system controller to emit blue light at varying output powers in a time-division manner, synchronized with phosphor wheel rotation, to enhance luminance uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If blue laser light sources with different central wavelengths (445 nm and 465 nm) are used to generate colored light for left-eye and right-eye images, then stereoscopic 3D image display is achieved, but non-uniformity in luminance occurs due to different fluorescence yields of phosphors at different excitation wavelengths
Solution Approach 1:
The system uses a phosphor wheel that rotates periodically to alternately expose different phosphor regions to the blue laser light. The phosphor wheel contains multiple phosphor segments (yellow, cyan, magenta) arranged in a circular pattern, and its rotation enables time-division multiplexing of different color channels, achieving stereoscopic 3D display while managing luminance variations through periodic action
Solution Approach 2:
The system dynamically adjusts the output power of the blue laser light source based on the rotation position of the phosphor wheel and the specific phosphor segment being excited. By varying the laser power in real-time according to the phosphor's fluorescence characteristics at different wavelengths, the system compensates for luminance non-uniformity and maintains consistent brightness across different color channels and eyes
2Device complexity
If a single blue laser light source is used for both left-eye and right-eye image generation, then device complexity is reduced, but it becomes impossible to achieve spectroscopic 3D effect requiring different wavelengths
Solution Approach 1:
The system merges the functions of multiple light sources into a single blue laser light source by using a rotating phosphor wheel to create different color outputs. The phosphor wheel acts as a wavelength converter, transforming the single blue wavelength into multiple effective wavelengths (yellow, cyan, magenta) that are then used for stereoscopic 3D display, thus combining multiple light source functions into one device
Solution Approach 2:
The phosphor wheel serves as an intermediary between the single blue laser light source and the requirement for multiple wavelengths. It converts the blue light into different color bands through selective phosphor excitation, enabling the system to achieve spectroscopic 3D effect without needing multiple separate light sources with different wavelengths
3Ease of manufacture
If blue light with central wavelength of 465 nm is used, then the light source can be easily obtained, but the fluorescence yield of phosphors drops significantly compared to 445 nm wavelength
Solution Approach 1:
The system changes the operational parameters of the blue laser light source dynamically. Instead of using a fixed wavelength, the system adjusts the wavelength selection (between 445 nm and 465 nm) and output power based on which phosphor segment is currently being excited. This parameter adjustment optimizes the fluorescence yield for each phosphor type while maintaining ease of manufacture through a single laser source
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
Improves luminance uniformity of light forming images for both eyes by reducing the difference in fluorescence yield between phosphors, thereby enhancing viewing quality.
Implementation Method 1
a phosphor wheel configured to receive the blue light, allow the blue light to pass through, and create fluorescent light excited by the blue light received from the light source
Data Source
AI summary
A spectroscopic 3D image display device according to the present disclosure includes: at least one first projection type image display device that uses first illumination light to display an image; at least one second projection type image display device that uses second illumination light to display an image; and a system controller that carries out control so that the first and second projection type image display devices are synchronously driven. A light source device of the first projection type image display device emits, with prescribed output power, first blue light having the central wavelength λa, and switches the intensity of the output power and emits third blue light. A light source device of the second projection type image display device emits, with prescribed output power, second blue light having the central wavelength λb. The central wavelengths λa, λb, and λc satisfy λb≤λc<λa.