HMD Display Scattering Layer Layout for Screen Door Reduction
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Solution Overview
Problem
Conventional head-mounted displays (HMDs) suffer from a 'screen door' effect due to the area between neighboring pixels being displayed in black when an enlarged image is implemented, leading to reduced light efficiency and image quality.
Innovation Solution
A display apparatus with a substrate featuring pixel and non-pixel areas, pixel electrodes, a scattering layer with varying light scattering rates, an encapsulation layer with an inorganic stack structure, and a light-shielding layer to improve light efficiency by scattering incident light and preventing color mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a lens is used to enlarge the image in HMD, then a wide viewing angle is realized, but a screen door effect occurs and light efficiency is reduced
Solution Approach 1:
The display surface is segmented into pixel areas and non-pixel areas, with the scattering layer selectively positioned to cover only the non-pixel areas. This segmentation allows light to pass through pixel areas directly while scattering light from non-pixel areas, eliminating the screen door effect without compromising the enlarged image quality provided by the lens.
Solution Approach 2:
A scattering layer is introduced as an intermediary element between the pixel electrodes and the viewer. This scattering layer acts as a mediator that selectively scatters light from non-pixel areas while allowing light from pixel areas to pass through, thereby eliminating the screen door effect and improving light efficiency simultaneously.
2Ease of manufacture
If the scattering layer covers the entire pixel area, then the screen door effect is eliminated, but light efficiency is reduced
Solution Approach 1:
The scattering layer is applied with local quality differentiation: it is present in non-pixel areas to scatter light and eliminate the screen door effect, while it is absent or minimized in pixel areas to allow direct light transmission. This localized application ensures that each area has the appropriate optical property for its function.
Solution Approach 2:
The scattering layer is segmented to cover only specific regions (non-pixel areas) rather than the entire display surface. This segmentation strategy eliminates the screen door effect in areas where it occurs while preserving light transmission in pixel areas, thereby maintaining high light efficiency.
3Device complexity
If conventional display structure is used, then manufacturing is simple, but image blurring occurs between neighboring pixels
Solution Approach 1:
A light-shielding layer is introduced as an intermediary element positioned between neighboring pixel areas. This layer acts as a barrier that prevents light from one pixel area from spreading into adjacent non-pixel areas, thereby eliminating image blurring while maintaining a relatively simple overall structure.
Solution Approach 2:
The harmful optical interaction between neighboring pixels is extracted or removed by introducing the light-shielding layer. This layer takes out the unwanted light spread between pixels, preventing image blurring while keeping the display structure relatively simple and manageable.
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 solution enhances light efficiency and reduces the 'screen door' effect, resulting in improved image quality and reduced image blurring in head-mounted electronic devices.
Implementation Method 1
a scattering layer on the plurality of pixel electrodes, and including a plurality of non-scattering areas respectively at a central portion of each of the plurality of pixel areas, and a plurality of scattering areas respectively between neighboring non-scattering areas
Implementation Method 2
a layer of the insulating layer that is closest to the buffer layer may include an inorganic layer having a refractive index that is greater than a refractive index of the buffer layer
Data Source
AI summary
A display apparatus includes a substrate including a plurality of pixel areas spaced from each other, and a plurality of non-pixel areas respectively located between neighboring pixel areas, a plurality of pixel electrodes respectively located in at least a part of the plurality of pixel areas, and a scattering layer on the plurality of pixel electrodes, and including a plurality of non-scattering areas respectively at a central portion of each of the plurality of pixel areas, and a plurality of scattering areas respectively between neighboring non-scattering areas.