Compact HMD Optical System Using Transmissive Reflective Lenses
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Solution Overview
Problem
Existing head mount display (HMD) optical systems face challenges in achieving a wide field of view, high optical performance, and a compact size while maintaining image quality, due to limitations in the design of folding optical systems with a single lens, which results in increased overall length and weight, leading to user discomfort.
Innovation Solution
The optical system comprises a first lens with a transmissive reflective surface, a second lens with a quarter waveplate, and a third lens with a transmissive reflective surface, where the second lens is positioned between the reflective surfaces, allowing the light beam to transmit through and be reflected multiple times, reducing overall length and preventing light leakage, and enabling high magnification and optical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a folding optical system with a single lens is used, then the overall optical length is reduced, but the image quality cannot be improved
Solution Approach 1:
The optical system is divided into three separate lenses (first lens, second lens, third lens) instead of using a single lens. Each lens is positioned at specific locations with defined optical paths, allowing the system to achieve both compact length and improved image quality through distributed optical elements that can be individually optimized
Solution Approach 2:
The patent introduces transmissive reflective surfaces that operate in a different dimensional aspect of light control. These surfaces combine reflection and transmission properties in a way that adds a new dimension to optical path management, enabling compact folding while maintaining image quality through multi-dimensional light control
2Manufacturing precision
If the optical system uses multiple lenses and reflective surfaces, then image quality is improved, but the overall length and weight increase
Solution Approach 1:
The optical elements are arranged in a nested configuration where the second lens is positioned between the first and third lenses, and the transmissive reflective surfaces are integrated at specific positions. This nested arrangement allows multiple optical functions to be combined in a compact space, reducing overall length while maintaining high image quality through multiple lenses
Solution Approach 2:
The patent employs adjustable optical elements including a variable focus lens and transmissive reflective surfaces that can dynamically control light paths. This dynamic capability allows the system to optimize image quality while maintaining a compact form factor, as the optical elements can be adjusted to achieve best performance without increasing overall dimensions
3Manufacturing precision
If the optical system uses multiple lenses and reflective surfaces, then image quality is improved, but the weight increases
Solution Approach 1:
Each lens and reflective surface is designed with specific local optical properties optimized for its particular function in the system. The transmissive reflective surfaces are positioned at critical locations where they provide maximum optical benefit, allowing high image quality with minimal material usage and reduced overall weight through localized optimization
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 provides a compact optical system with high optical performance, reducing user burden by maintaining a short overall length, minimizing weight, and enhancing image quality while allowing for inner focusing and diopter adjustment, thus providing a more comfortable and realistic viewing experience.
Implementation Method 1
a first lens having a first transmissive reflective surface on the display surface side, a second lens, and a third lens having a second transmissive reflective surface on the pupil surface side
Implementation Method 2
A quarter waveplate is provided to a surface on the pupil surface side of the second lens
Implementation Method 3
The light beam from the display surface transmits through the third lens and the second lens in this order, is reflected by the first transmissive reflective surface toward the display surface
Data Source
AI summary
An optical system is configured to guide a light beam from a display surface to a pupil surface, and includes, in order from a pupil surface side to a display surface side, a first lens having a first transmissive reflective surface on the display surface side, a second lens, and a third lens having a second transmissive reflective surface on the pupil surface side. A quarter waveplate is provided to a surface on the pupil surface side of the second lens. The second lens and the third lens are spaced apart from each other. The light beam from the display surface transmits through the third lens and the second lens in this order, is reflected by the first transmissive reflective surface toward the display surface, transmits through the second lens, and is reflected toward the pupil surface by the second transmissive reflective surface, transmits through the second lens and the first lens in this order, and enters the pupil surface.