Eyepiece Chief Ray Height Control for Wide Eye Box
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Solution Overview
Problem
Conventional optical systems with digital display units lack a conjugate equipment pupil, leading to unsharp images when the eye position deviates from the optimal viewing range, causing discomfort and difficulty in adjusting the eye position without clear guidance.
Innovation Solution
An optical system design that includes a display unit with a defined edge and an eyepiece featuring a lens unit, where the marginal ray light beam's chief ray propagates at specific heights, ensuring a large pupil distance and half field angle, and optionally includes multiple lenses with aspheric surfaces to maintain image quality and provide feedback on eye position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional optical system with digital display unit is used, then the system structure is simple, but the image becomes unsharp when eye position deviates from optimal viewing range
Solution Approach 1:
The optical system is divided into multiple lens groups (first lens group with positive refractive power, second lens group with negative refractive power, third lens group with positive refractive power) that work together to correct optical aberrations and maintain image quality over a larger eye box region
Solution Approach 2:
Different lens groups are designed with specific local optical properties (positive or negative refractive power) to address different aspects of image quality and eye position tolerance in various regions of the optical path
2Ease of operation
If the pupil distance is increased for spectacle wearers, then comfort is improved, but the half field angle and image quality may deteriorate
Solution Approach 1:
The optical system is designed with adjustable components and flexible optical paths that can adapt to different pupil distances, allowing the system to maintain image quality whether the user wears spectacles or not by optimizing the optical configuration for the specific viewing condition
3Manufacturing precision
If multiple lenses with aspheric surfaces are added to maintain image quality, then image sharpness is improved, but device complexity increases
Solution Approach 1:
Aspheric surfaces are incorporated into the lens designs to correct spherical aberration and other optical imperfections, allowing each lens to contribute more effectively to image quality without requiring an excessive number of additional lens elements
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
Enables comfortable viewing for spectacle wearers with a large pupil distance and half field angle, maintaining image quality and providing intuitive feedback on eye position adjustments, thus enhancing user experience.
Implementation Method 1
an eyepiece for observing the image, wherein, as seen in a light incidence direction, the display unit is arranged first, followed by the lens unit
Implementation Method 2
optionally includes multiple lenses with aspheric surfaces to maintain image quality
Data Source
AI summary
The invention relates to an optical system (7) having an optical axis (OA), having a display unit (5) for displaying an image, having an eyepiece (6) for viewing the image, the eyepiece (6) comprising a lens unit (L1). The display unit (5) is designed in such away that a marginal ray light beam (9) emanates from an edge (8) of the display unit (5) and propagates to the lens unit (L1) in a light incidence direction (L). The display unit (5) is arranged first along the optical axis (OA) in the light incidence direction (L), followed by the lens unit (L1) arranged on the optical axis (OA). No further optical unit of the optical system (7) is arranged between the lens unit (L1) and a pupil of the eye (2). The marginal ray light beam (9) has a chief ray (HS). The chief ray (HS) propagates at a first chief ray height (H1) at the lens unit (L1) and at a second chief ray height (H2) at the display unit (5). The first chief ray height (H1) is at least level with the second chief ray height (H2).