Variable-Focus Fresnel Lens for Display Border Reduction
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Solution Overview
Problem
Conventional display technologies suffer from non-light emitting border areas around LCD panels, leading to reduced viewable area, and cause spherical aberration, chromatic aberration, Moire patterns, and image ghosting issues, especially when viewed at large angles due to the use of heavy magnifying lenses or circular Fresnel lenses.
Innovation Solution
A display apparatus comprising a display panel with width-fixed and width-variating pixel zones and a lens with a focus-length-variating portion, where the lens has a planar portion aligned with the width-fixed pixel zone and microstructure groups corresponding to the border and width-variating pixel zones, reducing non-light emitting areas and interference stripes while promoting resolution uniformity and increasing the slant viewing angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a magnifying lens is used to reduce the border area and magnify the viewable area, then the viewable area is increased, but the lens becomes heavy and thick, causing spherical aberration and chromatic aberration
Solution Approach 1:
The lens is divided into multiple zones with different focal lengths, each zone corresponding to different pixel groups on the display panel. This segmentation allows the lens to be thinner while maintaining magnification functionality, reducing both weight and thickness compared to a single thick magnifying lens.
Solution Approach 2:
Different regions of the lens have different optical properties (focal lengths) matched to the local pixel density requirements. The lens structure adapts its focal length locally to correspond with pixel groups of different widths, reducing the need for a uniformly thick lens design.
2Length of stationary object
If a circular Fresnel lens is used to reduce lens thickness and weight, then the lens becomes thinner and lighter, but the periodical structure causes interference stripes and Moire patterns
Solution Approach 1:
The lens transitions from a uniform periodic Fresnel structure to a non-uniform structure where the focal length varies locally to match the pixel group widths. This local adaptation eliminates the periodic interference patterns while maintaining the thin lens advantage.
Solution Approach 2:
The focal length parameter of the lens is changed from a constant value to a spatially varying value that corresponds to the pixel group widths. This parameter variation eliminates Moire patterns while maintaining thin lens characteristics.
3Length of stationary object
If a Fresnel lens with large facet angle is used for magnification, then the lens can be thinner, but darker and lighter stripes and ghosting phenomena occur when viewed at large slant angles
Solution Approach 1:
The lens structure is optimized locally for different viewing angles and positions. The focal length variation across the lens surface compensates for angular deviations, reducing ghosting and stripe artifacts when viewed at slant angles while maintaining thin profile.
4Ease of manufacture
If the pixel widths are kept uniform across the display panel, then the manufacturing is simpler, but the resolution uniformity is poor and the border area cannot be effectively reduced
Solution Approach 1:
The pixel groups have different widths that correspond to different regions of the lens with different focal lengths. This local variation in pixel width, combined with the corresponding lens structure, achieves both resolution uniformity and effective border area reduction.
Solution Approach 2:
The pixel width parameter is varied across different regions of the display panel to match the focal length distribution of the lens. This parameter coordination between pixels and lens achieves uniform resolution while maximizing the viewable area.
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 effectively reduces non-light emitting areas, minimizes interference stripes, and enhances resolution uniformity and viewing angles by using a Fresnel lens with variating focus lengths and non-periodically varying pixel widths, resulting in a thinner and lighter display with reduced aberrations and ghosting phenomena.
Implementation Method 1
a conventional skill is directed to mounting a magnifying lens or circular Fresnel lens above a LCD panel for directly performing 2-dimensional area magnification
Implementation Method 2
The lens of this embodiment has a focus-length-variating portion and a planar portion
Implementation Method 3
the periodical structure of the Fresnel lens may interfere with the pixels area on the LCD panel to cause interference stripes, such as Moire patterns
Data Source
AI summary
A display apparatus is disclosed, and comprises a display panel and a lens. On the display panel, there are a width-fixed pixel zone, a width-variating pixel zone and a border zone arranged sequentially from the center to the edges of the display panel, wherein there are a plurality of width-fixed pixels disposed in the width-fixed zone, and there are a plurality of width-variating pixel groups disposed in the width-variating pixel zone, and the widths of the width-variating pixel groups are present in a first decreasing sequence. The lens has a focus-length-variating portion and a planar portion, wherein the planar portion is aligned with the width-fixed pixel zone, and the focus-length-variating portion is disposed to correspond to the border zone and the width-variating pixel zone. The focus lengths of the focus-length-variating portion corresponding to the width-variating pixel groups are present in a second decreasing sequence.