Thermochromic LED Structure Suppressing Blue Light Leakage
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Solution Overview
Problem
White LEDs experience reduced light emission efficiency and excessive blue light leakage as they approach the L70 threshold, leading to potential eye injury and the need for premature replacement, as existing technologies fail to effectively manage heat-induced color changes and blue light emission.
Innovation Solution
A blue light leakage-suppressing LED structure incorporating a thermochromics material that changes hue when the LED reaches high temperatures, reducing brightness and blocking blue light emission, thereby protecting eyes and indicating the need for replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the LED operates continuously to maintain brightness, then the service life is extended, but blue light leakage increases causing eye injury risk
Solution Approach 1:
The patent applies a thermochromic material that changes color from transparent to blue when the LED junction temperature reaches the L70 threshold. This color change mechanism provides visual warning of excessive blue light emission, allowing users to replace the LED before eye injury occurs, thus resolving the contradiction between extended service life and blue light safety
Solution Approach 2:
The thermochromic material acts as an intermediary indicator between the LED's internal temperature state and the user's perception. It translates the invisible thermal condition (L70 threshold) into a visible color change, enabling users to take preventive action against blue light exposure while maximizing the LED's usable lifespan
2Illumination intensity
If the LED operates at high temperature to maintain luminous flux, then the brightness is sustained, but the correlated color temperature increases causing blue light emission
Solution Approach 1:
The thermochromic material changes color in response to the LED's correlated color temperature increase. When the CCT rises above 9000K indicating excessive blue light emission, the material turns blue, providing visual feedback that allows users to balance luminous flux requirements against color temperature safety limits
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
The solution effectively reduces blue light exposure and notifies users to replace the LED before it malfunctions, enhancing energy efficiency and user safety by incorporating a thermosensitive material that changes color and reduces light permeability when the LED approaches the L70 threshold.
Implementation Method 1
a thermochromics material that changes hue when the LED reaches high temperatures
Implementation Method 2
an optical fuse coating formed of a thermosensitive material and applied to an outer surface of the light output lens
Data Source
AI summary
A blue light leakage-suppressing LED structure for emitting white light includes at least one LED chip, an encapsulation element, a light output lens, and an optical fuse coating formed of a thermosensitive material; or includes at least one LED chip and an encapsulation element formed of a mixture of an encapsulation material and a thermosensitive material; or includes at least one blue LED chip, a fluorescent powder layer, an isolation region, an optical fuse layer, and a light output lens. Thanks to the hue changing property of the thermosensitive material, the LED structure can reduce the intensity of its short-wavelength light component and its overall brightness significantly before reaching the L70 threshold, after passing which the LED structure will emit excessive blue light. Thus, the user is protected from overexposure to blue light and will be reminded to replace the LED structure when the LED structure is about to malfunction.