Structured Optical Surface Diffracts Light to Fill Pixel Gaps
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Solution Overview
Problem
Pixelated displays often exhibit gaps between adjacent pixels and sub-pixels, leading to optical artifacts known as the screen-door effect, which can be objectionable to viewers, especially in head-mounted displays.
Innovation Solution
A structured optical surface is provided, featuring a plurality of three-dimensional structures formed by the intersection of at least first and second Fresnel patterns. This surface images sub-pixels onto an image surface as corresponding imaged sub-pixels spaced apart by a corresponding imaged gap and diffracts light to partially fill the imaged gap without overlapping the imaged sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a pixelated display surface is used, then the display can be manufactured with discrete pixels and sub-pixels, but gaps appear between adjacent pixels and sub-pixels causing the screen-door effect
Solution Approach 1:
A structured optical surface is introduced as an intermediary element between the pixelated display surface and the viewer's eye. This optical surface includes multiple diffractive structures that redirect light from sub-pixels into the gap regions, effectively filling the visual gaps without requiring physical filling materials or structural modifications to the display itself.
Solution Approach 2:
The patent replaces the mechanical approach of physically filling gaps between pixels with an optical solution. Instead of using materials or structures to block gaps mechanically, the invention uses diffractive optical elements to redirect light waves into gap regions, substituting mechanical gap-filling with optical light redirection.
2Object-affected harmful factors
If light is diffracted to fill the gaps between sub-pixels, then the screen-door effect is reduced, but light may overlap with imaged sub-pixels
Solution Approach 1:
The structured optical surface is designed with spatially varying diffractive structures where different regions have different diffractive properties. The structures are configured to redirect light specifically into gap regions while maintaining distinct optical paths that prevent overlap with imaged sub-pixels, achieving local differentiation of optical functions.
Solution Approach 2:
The patent utilizes angular dispersion and spatial frequency modulation in the diffractive structures to control light propagation in multiple dimensions. By designing the diffractive patterns with specific spatial frequencies and orientations, the system achieves precise control over where light is redirected, filling gaps in one dimension while avoiding overlap in other dimensions.
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 structured optical surface effectively reduces the screen-door effect by partially filling the gaps between imaged sub-pixels with diffracted light, thereby improving the visual quality of pixelated displays.
Implementation Method 1
the structured optical surface diffracts light so that the diffracted light at least partially fills the imaged gap without substantially overlapping any of the at least two imaged sub-pixels
Implementation Method 2
substantially refracts a different second portion of the incident light so that the substantially refracted light makes an oblique angle with the structured optical surface
Data Source
AI summary
A structured optical surface and an optical imaging system including the structured optical surface is described. The structured optical surface includes a plurality of structures formed by an intersection of at least first and second Fresnel patterns, such that when the structured optical surface is incorporated in an optical imaging system comprising a pixelated display surface with at least one pixel comprising at least two sub-pixels spaced apart by a gap, the structured optical surface images the at least two sub-pixels onto an image surface as at least two corresponding imaged sub-pixels spaced apart by a corresponding imaged gap, and the structured optical surface diffracts light so that the diffracted light at least partially fills the imaged gap without substantially overlapping any of the at least two imaged sub-pixels.