Near-eye Light Field Display Shielding for Ghost Image Interference
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Solution Overview
Problem
Near-eye light field display devices face interference issues due to the human eye movement range being reduced by the micro-lens array, leading to ghost images and a decreased depth of field, especially when the pupil is positioned at the edge of the display's range.
Innovation Solution
Incorporating a micro-lens array with first and second shielding elements, each with shielding regions, to create a pinhole-like effect by reducing the interference between the main and ghost images and increasing the optical depth of field through the use of thin transparent sheets or opaque coatings, ensuring the ratio of micro-lens diameter to lens pitch is less than 0.8.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a micro-lens array is used to pass light field sub-images, then a light field image with depth can be formed, but the micro-lens array generates marginal rays that expand the human eye movement range and cause interference between main and ghost images
Solution Approach 1:
A shielding element is introduced as an intermediary component between the micro-lens array and the display element. This shielding element includes shielding regions that selectively block marginal rays while allowing chief rays to pass through. By positioning the shielding element at a specific distance from the micro-lens array, the patent effectively separates the useful light paths from the harmful marginal rays, eliminating ghost image interference while preserving the depth of field effect
Solution Approach 2:
The shielding element is designed with non-uniform shielding regions that have different properties at different locations. The shielding regions are specifically configured to block only the marginal rays that cause interference, while allowing the central chief rays to pass through unchanged. This localized shielding approach maintains the optical quality where needed while eliminating interference in specific directions
2Use of energy by moving object
If the micro-lens array has a larger lens diameter to improve light transmission, then more light reaches the display element, but the human eye movement range expands further causing increased interference
Solution Approach 1:
The shielding element acts as a mediator that decouples the relationship between lens diameter and interference. By introducing this intermediate component, the system can use larger micro-lens diameters for improved light transmission while the shielding element simultaneously blocks the expanded marginal rays that would otherwise cause interference. This allows the system to optimize light transmission without being constrained by the interference problem
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
This configuration reduces the interference between the main and ghost images, enhances the depth of field, and improves the depth display effect by increasing the aperture value, thereby providing a clearer and more immersive light field experience.
Implementation Method 1
The micro-lens array has multiple micro-lenses connected to each other. The first shielding element is located between the display element and the micro-lens array... The micro-lens array is located on a transmission path of the image beam.
Implementation Method 2
The first shielding regions and the second shielding regions are located on the transmission path of the image beam passing through a junction of the micro-lenses... reducing the interference of the human eye movement range between the main image and the ghost image.
Data Source
AI summary
A near-eye light field display device, including a display element, a micro-lens array, a first shielding element, and a second shielding element, is provided. The display element is configured to provide an image beam. The micro-lens array is located on a transmission path of the image beam. The micro-lens array has multiple micro-lenses connected to each other. The first shielding element is located between the display element and the micro-lens array, and the first shielding element includes multiple first shielding regions. The micro-lens array is located between the first shielding element and the second shielding element. The second shielding element includes multiple second shielding regions. The first shielding regions and the second shielding regions are located on the transmission path of the image beam passing through a junction of the micro-lenses, and a ratio of diameter of the micro-lenses and a lens pitch of the micro-lenses is less than 0.8.