Extended Depth of Focus AR Display via Convergence Area Control
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Solution Overview
Problem
Conventional augmented reality and virtual reality head-mounted display products face challenges such as eye fatigue and image blurring due to lack of eye accommodation information, leading to poor user experience, especially when displaying 3D objects at close distances, and existing 3D image display apparatuses are hindered by size and volume constraints in providing extended depth of focus.
Innovation Solution
An image display apparatus with an extended depth of focus (DOF) is designed, incorporating a display unit, an optical element unit with a lens and pinhole, and a control unit that adjusts the convergence area size to equalize near and far position image blurs, allowing for a best image point position at the arithmetic mean of the eye's accommodation positions, and includes an eye-tracking system for focal distance adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional 3D image display apparatus uses laser source, optical beam expander, light modulator, pinholes, and lenses to provide parallax images, then depth of focus is extended, but device size and volume increase
Solution Approach 1:
The patent combines the optical element unit (lens and pinhole) with the display unit into a compact integrated structure. The optical element unit is disposed at a predetermined distance from the front surface of the display unit, merging multiple optical functions into a single compact module that extends depth of focus without proportionally increasing device volume.
Solution Approach 2:
The patent introduces a new spatial dimension by positioning the optical element unit at a specific predetermined distance from the display unit front surface, and forming the convergence area at a different distance. This multi-level spatial arrangement allows extended depth of focus while maintaining a compact overall device footprint.
2Device complexity
If conventional HMD products display 3D images without eye accommodation information, then device structure is simplified, but eye fatigue and image blurring occur
Solution Approach 1:
The patent incorporates an eye-tracking system that detects the user's gaze direction and focal distance, providing feedback to the control unit. The control unit then adjusts the convergence area size dynamically based on this feedback, ensuring images remain focused and reducing eye fatigue without significantly complicating the device structure.
Solution Approach 2:
The patent makes the convergence area size adjustable and dynamic rather than fixed. The control unit changes the convergence area size in response to eye accommodation changes, allowing the system to adapt to different viewing distances and reduce image blurring while maintaining relatively simple hardware architecture.
3Manufacturing precision
If projection optical system is used to enlarge image and adjust focus, then image quality is improved, but device volume increases
Solution Approach 1:
The patent segments the optical system into distinct functional units: the display unit, the optical element unit (containing lens and pinhole), and the main optics lens. This segmentation allows each component to be optimized independently for image quality while keeping the overall volume manageable through precise spatial arrangement.
Solution Approach 2:
The patent optimizes specific optical parameters including the predetermined distance between the display unit front surface and the optical element unit, the convergence area size, and the positioning of the main optics lens. By carefully adjusting these parameters, the system achieves high image quality with extended depth of focus without requiring a bulky projection optical system.
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 minimizes eye fatigue and image blurring by extending the DOF, enabling clear visualization of 3D images across a range of distances without significant size or volume increases, thereby enhancing user experience in augmented and virtual reality applications.
Implementation Method 1
an optical element unit disposed to be spaced apart from a front surface of the display unit by a predetermined distance (Dmd) and including a lens and a pinhole
Implementation Method 2
configured to form a convergence area of a virtual image on a pupil of an eye of a user
Implementation Method 3
the size of each of the near and far position image blurs is within 20% of the same value as a size of an image blur due to diffraction
Data Source
AI summary
The present disclosure relates to an image display apparatus with an extended depth of focus (DOF) and a method of controlling the same. The image display apparatus with an extended DOF includes a display unit, an optical element unit disposed to be spaced apart from a front surface of the display unit by a predetermined distance (Dmd) and including a lens and a pinhole that has an opening portion (PDml), a main optics lens disposed to be spaced apart from a front surface of the optical element unit by a predetermined distance (Do) and configured to form a convergence area of a virtual image on a pupil of an eye of a user, and a control unit that performs a control for extending a DOF with respect to the virtual image provided to the user.