Avionics LED Light Box with Photodetector Control
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Solution Overview
Problem
Light-emitting diode (LED) light boxes for liquid crystal displays in avionics suffer from non-uniform illumination due to failures in diodes or power supplies, leading to variations in luminosity, which can impair legibility during critical flight conditions.
Innovation Solution
The light box design features light-emitting diodes organized in alternating rows with independent power supplies, along with photodetectors and color filters to ensure uniformity and maintain sufficient luminosity, using a lightguide with a diffusing optical structure to distribute light evenly across the display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If LEDs are organized in single row with single power supply, then device complexity is reduced, but illumination uniformity deteriorates when diodes fail
Solution Approach 1:
The LED array is divided into multiple rows, with each row supplied by an independent power supply. This segmentation ensures that a failure in one row does not affect other rows, maintaining illumination uniformity and reliability while keeping the overall system manageable through modular power supply units.
Solution Approach 2:
Each row of LEDs is equipped with its own dedicated power supply, creating local independence. This allows each segment of the LED array to operate autonomously, ensuring that localized failures do not propagate to other areas, thereby maintaining overall illumination quality and uniformity.
2Illumination intensity
If fluorescent tubes are used for backlighting, then illumination intensity is sufficient for daytime vision, but volume of light box increases and maintenance requirements increase
Solution Approach 1:
The patent replaces fluorescent tubes with LED technology, substituting the mechanical/electromagnetic fluorescent lighting system with a solid-state LED system. This substitution maintains sufficient illumination intensity for daytime vision while dramatically reducing the volume required and eliminating the need for regular maintenance of fluorescent tubes.
3Illumination intensity
If fluorescent tubes are used for backlighting, then illumination intensity is sufficient for daytime vision, but maintenance requirements increase due to tube lifetime
Solution Approach 1:
The patent replaces fluorescent tubes with LED technology, substituting the mechanical/electromagnetic fluorescent lighting system with a solid-state LED system. This substitution maintains sufficient illumination intensity for daytime vision while eliminating the need for regular maintenance of fluorescent tubes, as LEDs have significantly longer operational lifetimes and no filament degradation issues.
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
This configuration minimizes variations in illumination, ensuring consistent and sufficient light output even if one or more rows of LEDs fail, maintaining readability of avionic displays and allowing for servocontrol of luminance to adjust to varying light conditions.
Implementation Method 1
a lightguide (62) having, on one of the faces (64) turned toward the bottom (52) of the case (51), an optical structure (70) for diffusing the light propagating in the lightguide
Implementation Method 2
an optical structure (70) for diffusing the light propagating in the lightguide
Implementation Method 3
light-emitting diodes (Lnm) placed linearly along at least one of the edges (B1, B2, B3, B4) of the lightguide (41)
Implementation Method 4
light-emitting diodes (Lnm) placed linearly along at least one of the edges (B1, B2, B3, B4) of the lightguide (41), the light emitted by the light-emitting diodes
Implementation Method 5
at least one photodetector delivering a luminous intensity signal corresponding to the light emitted by the box
Data Source
AI summary
A box includes a lightguide in the form of a thin plate having two opposed main faces and at least two edges, the lightguide having a light-diffusing optical structure on one of the faces. Light-emitting diodes are placed linearly along at least one of the edges of the lightguide, the light emitted by the light-emitting diodes illuminates the lightguide via the edge, and is being diffused by that face of the lightguide having the optical structure. The light emitting diodes placed along each of the edges of the lightguide are organized in at least two rows and in such a way that a light-emitting diode in one row supplied by an electric power supply is immediately followed by a light-emitting diode in the other row supplied by another electric power supply.