Dual-Wavelength Display Backlight for Circadian Rhythm Control
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Solution Overview
Problem
Conventional display apparatuses do not consider human circadian rhythms, emitting light that can disrupt the body's natural melatonin and serotonin secretion, affecting sleep quality and overall health.
Innovation Solution
Incorporating a backlight unit with two light sources emitting different wavelengths - blue (440-450 nm) and sky blue (475-505 nm) LEDs, controlled by separate power supplies and a processor to adjust current intensity, simulating day and night conditions based on sunrise and sunset detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single light source emitting blue light (440-450 nm) is used in the backlight unit, then the display apparatus can maintain image quality and brightness, but it disrupts human circadian rhythm by suppressing melatonin secretion and affecting sleep quality
Solution Approach 1:
The single blue light source is segmented into two distinct light sources: a first light source emitting blue light (440-450 nm) and a second light source emitting sky blue light (475-505 nm). This segmentation allows independent control of each wavelength range, enabling the system to maintain brightness while avoiding circadian rhythm disruption by adjusting the intensity ratio between the two sources.
Solution Approach 2:
The patent changes the spectral parameters by introducing a second light source with a different wavelength range (475-505 nm). The controller dynamically adjusts the intensity parameters of both light sources based on time of day, ensuring that the combined output maintains adequate brightness while reducing the harmful impact on melatonin secretion during nighttime hours.
2Illumination intensity
If the intensity of blue light is increased to maintain display brightness, then image quality is preserved, but the harmful effect on melatonin secretion and sleep quality is intensified
Solution Approach 1:
The patent changes the spectral composition parameters by adding sky blue light (475-505 nm) to the blue light spectrum. This parameter change allows the system to achieve adequate display brightness through the combined output of both light sources, while the presence of sky blue light reduces the relative intensity of the harmful blue light wavelength range, thereby minimizing melatonin suppression.
Solution Approach 2:
The patent creates a composite light output by combining two different wavelength ranges (blue light and sky blue light) from two separate LED sources. This composite approach produces a combined spectrum that maintains the brightness required for good display quality while reducing the concentration of the most harmful wavelengths that suppress melatonin secretion.
3Object-affected harmful factors
If a backlight unit with two light sources of different wavelengths is used, then healthy melatonin secretion is promoted and circadian rhythm is maintained, but the device complexity increases due to separate power supply parts and control mechanisms
Solution Approach 1:
The controller serves multiple functions: it manages both light sources, adjusts their intensity ratios, detects ambient light conditions, and determines optimal emission patterns based on time of day. This multi-functionality consolidates what could be separate complex systems into a single integrated control unit, managing the dual light source system efficiently without proportionally increasing overall device complexity.
Solution Approach 2:
The patent merges the control of both light sources into a single integrated controller that manages the first and second power supply parts. This consolidation allows coordinated operation of the two light sources, enabling the system to achieve circadian rhythm benefits while avoiding the complexity of completely separate control systems. The merged control structure optimizes the combined output of both wavelengths simultaneously.
4Illumination intensity
If the first light source emits maximum current continuously, then display brightness is maximized, but it causes harmful effects on human health by disrupting circadian rhythm all day long
Solution Approach 1:
The patent implements periodic action by controlling the first light source to emit blue light at maximum intensity during daytime hours and reducing or stopping emission during nighttime hours. The controller uses time-based logic and ambient light detection to determine when to switch between emission modes, creating a periodic pattern that aligns with natural circadian rhythms and eliminates continuous harmful exposure.
Solution Approach 2:
The system transitions from a static maximum emission mode to a dynamic control mode where the intensity and operation of the first light source are continuously adjusted based on ambient light conditions and time of day. This dynamic behavior allows the display to maintain optimal brightness during daytime while automatically reducing harmful emissions during nighttime, adapting to environmental conditions in real-time.
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 display apparatus effectively mimics natural daylight and nighttime conditions, promoting healthy melatonin secretion and serotonin suppression, while maintaining image quality and brightness.
Implementation Method 1
a first light source emitting light of a first wavelength and a second light source emitting light of a second wavelength different from the first wavelength... The first light source may include a plurality of blue LEDs, and the second light source may include a plurality of sky blue LEDs
Data Source
AI summary
An display apparatus may include a liquid crystal; a color filter overlapping the liquid crystal; a backlight unit to supply light to the liquid crystal and including a first light source emitting light of a first wavelength and a second light source emitting a second wavelength different from the first wavelength; a first power supply part to supply a first current to the first light source; a second power supply part to supply a second current to the second light source; and a processor which may control the first power supply part and the second power supply part so that the first and second currents are simultaneously supplied to the first light source and the second light source. The processor may control the first power supply part and the second power supply part so that intensity of the first current supplied to the first light source is different from intensity of the second current supplied to the second light source.