Display Device Blue Filter Segmentation for Melatonin Disruption
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Solution Overview
Problem
Display devices emit light with a peak wavelength of about 460 nm, which can disrupt human sleep patterns by controlling melatonin production, leading to insomnia.
Innovation Solution
A liquid crystal display device is designed with a first blue filter having a peak transmittance at a wavelength shorter than 460 nm and a second blue filter with a peak transmittance at a wavelength longer than 460 nm, arranged alternately with red and green filters to prevent the emission of light at 460 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a conventional blue filter is used in the display device, then the display can show blue colors effectively, but light with a peak wavelength of about 460 nm is emitted which disrupts human sleep patterns
Solution Approach 1:
The blue filter is divided into two separate filters: a first blue filter with peak transmittance at wavelengths shorter than 460 nm and a second blue filter with peak transmittance at wavelengths longer than 460 nm. This segmentation allows the display to maintain blue color representation while eliminating the harmful 460 nm wavelength that disrupts melatonin production.
Solution Approach 2:
Different regions of the blue spectrum are treated differently by using two distinct blue filters with different transmittance characteristics. The first blue filter transmits shorter wavelengths while the second blue filter transmits longer wavelengths, creating localized quality differences that avoid the harmful 460 nm peak while maintaining overall blue color display.
2Object-affected harmful factors
If the blue filter transmittance peak is shifted away from 460 nm, then harmful light emission is reduced, but the blue color display quality may be compromised
Solution Approach 1:
Two blue filters with different transmittance peaks are combined to work together in the same display device. The first blue filter handles the shorter wavelength portion of the blue spectrum while the second blue filter handles the longer wavelength portion, merging their effects to maintain comprehensive blue color display while avoiding the harmful 460 nm wavelength.
Solution Approach 2:
The transmittance peak parameters of the blue filters are changed from a single peak at 460 nm to two separate peaks at wavelengths shorter and longer than 460 nm. This parameter change maintains the overall blue light output necessary for color display while shifting the peak emission away from the harmful 460 nm wavelength that disrupts sleep patterns.
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 device effectively prevents the emission of light at 460 nm, thereby reducing the risk of insomnia and improving sleep quality by using specific filter configurations and light sources.
Implementation Method 1
a first blue filter opposed to the third pixel electrode and having a peak of transmittance at a wavelength shorter than 460 nm
Implementation Method 2
a second blue filter opposed to the fourth pixel electrode and having a peak of transmittance at a wavelength longer than 460 nm
Data Source
AI summary
According to one embodiment, a first substrate includes first to fourth pixel electrodes. A color filter layer includes a red filter opposed to the first pixel electrode, a green filter opposed to the second pixel electrode, a first blue filter opposed to the third pixel electrode and having a peak of transmittance at a wavelength shorter than 460 nm, and a second blue filter opposed to the fourth pixel electrode and having a peak of transmittance at a wavelength longer than 460 nm.