Phosphor Wheel Defect Detection in Illuminating Devices
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Solution Overview
Problem
Existing illuminating devices face challenges in detecting and addressing deterioration of phosphor layers and reflective mirrors, leading to flickering and changes in color ratios due to defective or degenerated sites, which complicates identifying the cause of these issues.
Innovation Solution
An illuminating device equipped with a photo detector and control unit that detects light passing through the phosphor wheel to determine defects or degeneration in the illuminating light generating members, allowing for precise identification and adjustment of light output to avoid irradiating defective areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If phosphor layer and reflective mirror are welded to metal plate using adhesive, then assembly is simplified and manufacturing is easier, but adhesive degradation causes peeling and deterioration over time
Solution Approach 1:
The patent extracts and removes the adhesive layer from the system by transitioning to a direct bonding method where phosphor layers and reflective mirrors are directly attached to the wheel substrate without adhesive, eliminating the source of degradation and peeling
Solution Approach 2:
The patent replaces the chemical bonding mechanism (adhesive) with a direct physical bonding mechanism (direct welding or bonding), substituting a degradable chemical system with a more stable mechanical/physical system
2Use of energy by moving object
If excitation light is radiated on phosphor layer, then illuminating light is generated, but heat generation deteriorates adhesive and induces peeling
Solution Approach 1:
The patent converts the harmful heat effect into a beneficial indicator by using the heat-generated light emission characteristics to detect deteriorated sites, turning a harmful factor into a diagnostic tool
Solution Approach 2:
The patent implements feedback by using photo detectors to monitor light from deteriorated sites and providing this information back to the control unit, which then adjusts excitation light irradiation to avoid worsening the deterioration
3Measurement precision
If photo detector detects light from deteriorated sites, then defect detection is enabled, but light utilization efficiency decreases
Solution Approach 1:
The patent extracts only the necessary detection function by using photo detectors to detect only light from deteriorated sites rather than collecting all light, minimizing interference with the main light path
Solution Approach 2:
The patent introduces photo detectors as intermediary elements that selectively detect light from deteriorated sites without blocking the main light path, acting as mediators between the phosphor layer and the external detection system
4Power
If excitation light irradiates defective sites, then no output light is generated, but power consumption increases without useful output
Solution Approach 1:
The patent makes the excitation light irradiation dynamic and adaptive by adjusting the irradiation pattern based on real-time detection of deteriorated sites, switching from static full-area irradiation to dynamic selective irradiation
Solution Approach 2:
The patent applies local quality by differentiating the treatment of different areas on the phosphor wheel, providing excitation light only to healthy areas while avoiding deteriorated sites, rather than uniform irradiation across the entire surface
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
Enables effective detection and management of defective or degenerated sites, maintaining light quality and efficiency by preventing wasteful power consumption and ensuring optimal luminance balance in the output light.
Implementation Method 1
a photo detector that is arranged on a second surface side that is opposite to the first surface of the wheel substrate to detect light that passed through the wheel
Implementation Method 2
Phosphor layer 103 includes a red phosphor area formed in the first segment and a green phosphor area formed in the second segment. As the wheel substrate rotates, the blue excitation light (circular polarization) is successively radiated on the first to third segments. In the first segment the phosphor excited by blue excitation light emits red fluorescence.
Implementation Method 3
In the third segments blue excitation light (circular polarization) is reflected by the reflective mirror
Implementation Method 4
The blue excitation light (S-polarization) reflected by dichroic mirror 115 is converted into circular polarization as it passes through quarter-wave plate 108
Data Source
AI summary
An illuminating device includes: a light source emitting excitation light; a wheel including a wheel substrate transmitting the excitation light and an illuminating light generating member provided on the first surface of the wheel substrate to generate illuminating light by the excitation light; a photo detector, arranged on the second surface side that is opposite to the first surface of the wheel substrate, detects light that passed through the wheel; and a control unit that determines whether a defect or degeneration has occurred in the illuminating light generating member, based on the light detected by the photo detector.