Edge-Lit Dust Cover Assembly for Electrochromic Window Reflection Control
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Solution Overview
Problem
Electrochromic or electro-optic windows exhibit increased spectral reflectivity in a darkened or opaque state, leading to visible reflections that can be irritating to observers, particularly in aircraft windows.
Innovation Solution
A window assembly with a dust cover assembly that includes edge-lit light sources, such as LEDs, integrated into a light transmitting sheet, which emits diffuse light to overpower specular reflections from the electro-optic element, reducing perceivable spectral reflectance by adjusting the intensity of illumination based on the electro-optic element's transmissivity and ambient light conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electrochromic windows are darkened to a opaque state, then the transparency is adjusted from fully-transparent to fully-opaque, but spectral reflectivity increases and reflections become visible and more perceptible
Solution Approach 1:
The patent applies the 'Blessing in disguise' principle by converting the harmful spectral reflectivity into a beneficial diffuse reflection. The dust cover assembly, which normally would just be a protective element, is transformed into an active optical component that emits diffuse light to counteract the harmful specular reflections from the electrochromic glass, thereby turning a potential aesthetic defect into a functional feature that improves optical appearance
Solution Approach 2:
The dust cover assembly serves as an intermediary element between the electrochromic glass and the external environment. It mediates the optical interaction by introducing a diffusely reflecting surface that intercepts and redistributes the reflected light, preventing direct specular reflections from reaching observers while maintaining the darkened state of the electrochromic glass
2Object-generated harmful factors
If dust cover assembly is illuminated with edge-lit light sources, then diffuse light is emitted to overpower specular reflections, but device complexity increases
Solution Approach 1:
The dust cover assembly is designed to perform multiple functions: it provides protective coverage for the electrochromic glass, serves as a structural element of the window assembly, and functions as an active optical component for diffuse reflection. By integrating these functions into a single component, the patent avoids adding separate elements that would increase complexity while achieving the desired optical effect
Solution Approach 2:
The patent merges the protective dust cover function with the optical diffusion function into a single integrated assembly. The light transmitting sheet is incorporated into the dust cover structure itself, combining what could have been separate components (protective cover + lighting system) into one unified element, thereby minimizing the increase in device complexity
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 diffuse illumination from the dust cover assembly significantly reduces the appearance of specular reflections, maintaining a perceivable level of reflectance below 30%R, thereby enhancing the optical appearance and comfort by minimizing the 'black mirror' effect in electrochromic windows.
Implementation Method 1
emits diffuse light to overpower specular reflections from the electro-optic element
Implementation Method 2
light sources (34) disposed at edges of a light transmitting sheet (36). The light sources (34) are configured to transmit light into the sheet (36) to illuminate the sheet (36) in a particular color and with a particular intensity
Data Source
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AI summary
A window assembly includes a pressure pane and a bezel proximate a periphery of the pressure pane and defining an inner opening. The bezel includes an inner wall with a channel. An electro-optic element is disposed in the inner opening and is received in the channel of the inner wall. The electro-optic element operates between a transmissive condition and a dimmed condition. A surface of the electro-optic element exhibits a first level of spectral reflectivity at least when in the dimmed condition. The assembly further includes a dust cover assembly proximate the bezel. The dust cover assembly including a light transmitting sheet and a plurality of light sources disposed at edges of the light transmitting sheet and to emit light into the light transmitting sheet to illuminate the light transmitting sheet with a diffuse light.