Virtual Image Phase Array Beveled Edge Transition
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Solution Overview
Problem
Conventional virtual image phase arrays (VIPA) have a wide transition zone between highly-reflective and partially-reflective surfaces, which necessitates a large entrance angle for incoming light, increasing the device's length and manufacturing complexity, and thus its cost.
Innovation Solution
A VIPA design featuring a beveled edge at an acute angle on the transparent support substrate and reflective coatings, forming a narrow transition region, allowing for a smaller entrance angle and reducing the device's length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional mask is used during coating deposition to control the transition zone width, then the transition zone width is controlled, but the mask geometry and deposition shadowing result in a transition zone width of 50 μm or more, increasing the entrance angle and device length
Solution Approach 1:
The patent removes the conventional mask from the coating deposition process entirely. Instead of using a mask to define the transition zone, the invention uses the substrate edge itself as the boundary, eliminating the mask's geometric limitations and shadowing effects that caused wide transition zones.
Solution Approach 2:
The patent transitions from a planar mask-based approach to a three-dimensional edge-based approach. By using the substrate's physical edge at an angle, the transition zone is defined by the geometry of the substrate edge rather than by mask projection, enabling precise control without the shadowing problems of conventional masking.
2Ease of manufacture
If a large transition zone is used to accommodate mask geometry and deposition shadowing, then the coating process is simplified, but the entrance angle must be large, increasing the device length and manufacturing complexity
Solution Approach 1:
The patent eliminates the mask from the manufacturing process, simplifying the coating procedure while simultaneously solving the problem of large transition zones. The substrate edge directly defines the transition zone boundary, removing the need for separate masking steps and mask alignment.
Solution Approach 2:
The substrate edge serves dual purposes: it provides the physical boundary for the coating and simultaneously defines the transition zone width. This self-defining characteristic eliminates the need for external masks and their associated alignment and shadowing problems.
3Length of moving object
If the transition zone width is reduced below 50 μm, then the entrance angle can be reduced and device length shortened, but conventional masking techniques cannot achieve this narrow width due to shadowing effects
Solution Approach 1:
The patent removes the mask-based system that causes shadowing and imprecision, replacing it with a direct geometric definition using the substrate edge. This extraction of the problematic mask element enables narrow transition zones to be achieved with high precision.
Solution Approach 2:
The patent uses the vertical dimension of the substrate edge at an angle to define the transition zone, rather than relying on horizontal mask projections. This dimensional change eliminates shadowing effects and enables precise control of narrow transition zones.
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 narrower transition zone enables a smaller entrance angle for incoming light, reducing the length of the VIPA and associated optics, simplifying manufacturing and lowering costs while maintaining spectral resolution.
Implementation Method 1
the transparent support substrate and the first reflective coating include a beveled edge at an acute angle from the second reflective surface forming a narrow transition region at the edge of the first reflective coating
Implementation Method 2
Light entering the VIPA through the input zone reflects back and forth across a gap formed by substrate between the highly and partially reflective surfaces
Implementation Method 3
The first highly-reflective surface also has an input, anti-reflection zone with an anti-reflection coating, which abuts the highly-reflective coating
Data Source
AI summary
A virtual image phase array (VIPA) includes two parallel surfaces, a first highly-reflective surface with a highly-reflective coating, and a second partially-reflective surface. The first highly-reflective surface also requires an input zone with an anti-reflection coating, which abuts the highly-reflective coating, with a transition zone therebetween. Light enters the VIPA through the input zone, and reflects back and forth between the highly and partially reflective surfaces, gradually leaking out through the partially reflective surface. To minimize the transition zone and thereby minimize the input angle of incidence and maximize the number of reflections per unit of length, the substrate coated with the highly-reflective coating is subsequently polished at an acute angle resulting in the transition zone having the same sharp angle.