Vehicle Ambient Lighting Notch Filter for Off-State Glow Prevention
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Solution Overview
Problem
Conventional vehicle lighting devices using phosphorescent materials unintentionally emit visible light due to excitation by external light sources, such as sunlight or artificial light, even when the devices are turned off.
Innovation Solution
Incorporating a notch filter at the second side of the lighting element to block external light wavelengths within the excitation range of the phosphorescent material, preventing unintentional excitation and light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a phosphorescent material is used to generate visible light in response to LED excitation light, then the lighting device can emit controlled visible light, but the device unintentionally emits visible light when external light sources (sunlight or artificial light) excite the phosphorescent material
Solution Approach 1:
A notch filter is introduced as an intermediary component between the external light source and the phosphorescent material. The filter selectively transmits wavelengths outside the excitation range while blocking excitation wavelengths, thereby preventing unintentional phosphorescent excitation by external light sources while allowing controlled excitation by the LED light source
Solution Approach 2:
The solution applies selective wavelength filtering at a specific location (the second side of the lighting element) to achieve different optical properties for different wavelength ranges. The notch filter creates local quality differentiation by allowing certain wavelengths to pass while blocking others, enabling the phosphorescent material to respond only to the LED light source and not to external light sources
2Device complexity
If the lighting device uses external light sources to excite the phosphorescent material, then the device structure can be simpler, but the lighting output becomes uncontrolled and power consumption increases
Solution Approach 1:
The notch filter acts as a mediator that enables the system to maintain simplicity while achieving reliable control. By filtering out excitation wavelengths from external light sources, the filter ensures that only the LED light source can excite the phosphorescent material, thereby maintaining controlled lighting output without requiring complex control mechanisms
Solution Approach 2:
The invention converts the potentially harmful effect of external light sources (which cause uncontrolled phosphorescent excitation) into a beneficial situation. The notch filter transforms external light from a source of interference into a controlled input, allowing the system to maintain simplicity while ensuring that external light does not compromise lighting control reliability
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
Effectively prevents unwanted light emission by blocking external light sources' excitation wavelengths, ensuring controlled light output and reducing power consumption through controlled ON/OFF cycles.
Implementation Method 1
a LED light source configured to emit excitation light of an excitation wavelength range
Implementation Method 2
a phosphorescent material configured to emit visible emission light of an emission wavelength range in response to being illuminated with the excitation light emitted by the LED light source
Implementation Method 3
at least one notch filter arranged at the second side of the at least one lighting element and configured to filter light in or of the excitation wavelength range out of light emitted by a light source external to the at least one lighting element
Data Source
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AI summary
An aspect of the present invention relates to a lighting device (1) for an ambient lighting system (100) of a vehicle (200), comprising: at least one lighting element (10, 20, 30) having a first side (11, 21, 31) and an opposite second side (12, 22, 32) facing a viewer (V) of the lighting device (1), the at least one lighting element (10, 20, 30) comprising: a LED light source (13, 23, 33) configured to emit excitation light (EX1, EX2, EX3) of an excitation wavelength range; a phosphorescent material (14, 24, 34) configured to emit visible emission light (EM1, EM2, EM3) of an emission wavelength range in response to being illuminated with the excitation light (EX1, EX2, EX3) emitted by the LED light source (13, 23, 33), the phosphorescent material (14, 24, 34) being arranged between the first and the second side (11, 21, 31; 12, 22, 32) of the at least one lighting element (10, 20, 30); and at least one notch filter (15, 25, 35) arranged at the second side (12, 22, 32) of the at least one lighting element (10, 20, 30) and configured to filter light in or of the excitation wavelength range of the excitation light (EX1, EX2, EX3) out of light emitted by a light source (40) external to the at least one lighting element (10, 20, 30) and incident in direction of the second side (12, 22, 32) of the at least one lighting element (10, 20, 30) on the phosphorescent material (14, 24, 34). Further aspects relate to a vehicle lighting system and a vehicle comprising said vehicle lighting system.