Pancake Lens Assembly With Folded Optics for Wearable Image Quality
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Solution Overview
Problem
Wearable electronic devices face challenges in providing good image quality while being miniaturized and lightweight due to limited lens configurations and increased refraction or scattering of light in pancake lens structures.
Innovation Solution
A lens assembly with a pancake lens structure that includes at least four lenses, a first polarizing plate, a beam splitter, and quarter-wave plates to guide visual information, allowing for aberration control and improved image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a pancake lens structure is used to miniaturize the wearable device, then the device size and weight are reduced, but light refraction and scattering increase causing degraded image quality
Solution Approach 1:
The lens assembly is divided into multiple lens units (first lens unit, second lens unit, third lens unit) with different optical functions. Each unit is optimized independently to control specific aberrations while contributing to the overall compact design, allowing miniaturization without sacrificing image quality
Solution Approach 2:
The patent employs composite lens structures combining different materials with distinct refractive indices and Abbe numbers. This allows precise control of chromatic and spherical aberrations within the compact pancake lens configuration, maintaining image quality while reducing device size
2Manufacturing precision
If the number of lenses is increased to improve image quality, then aberration control is enhanced, but the device becomes more complex and larger
Solution Approach 1:
Each lens unit is designed to perform multiple optical functions simultaneously. For example, the first lens unit not only focuses light but also corrects spherical aberration, while the second lens unit addresses both chromatic aberration and field curvature. This multi-functionality reduces the total number of lenses needed
Solution Approach 2:
The patent utilizes the optical path length dimension by implementing a folded optical path with reflective surfaces. This allows achieving the equivalent optical performance of a larger lens system within a compact form factor, reducing device complexity while maintaining image quality
3Manufacturing precision
If the optical path length is extended to improve image quality, then aberration control is enhanced, but the device length increases
Solution Approach 1:
The optical path is folded back on itself using reflective surfaces, transforming a linear optical path into a compact folded configuration. This extends the effective optical path length for aberration control while keeping the physical device length short, resolving the contradiction between optical performance and compact form factor
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 lens assembly provides miniaturized and lightweight wearable devices with enhanced image quality by extending the optical path length and reducing light scattering, thereby reducing user fatigue.
Implementation Method 1
a lens assembly configured to focus or guide the visual information output from the display
Implementation Method 2
a first polarizing plate disposed on an eye side surface of one of the at least four lenses
Implementation Method 3
a beam splitter disposed on a display side surface of the n th lens
Implementation Method 4
quarter-wave plates to guide visual information, allowing for aberration control and improved image quality
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
According to one embodiment of the present disclosure the wearable electronic device may comprise a lens assembly for focusing or guiding, on or to both eyes of a user, visual information that is output from a display. In one embodiment, the lens assembly can include: at least four lenses sequentially arranged in the direction toward the display along an optical axis; a first polarizing plate disposed on a user eye-side surface of one (hereinafter, referred to as "n-th lens") of the at least four lenses; a beam splitter disposed on a display-side surface of the n-th lens; and a second polarizing plate disposed on an eye-side surface of a user of an (n+1)-th lens disposed between the n-th lens and the display while being adjacent to the n-th lens from among the at least four lenses. In one embodiment, the first polarizing plate can reflect at least some of the visual information that is output from the display, and the beam splitter can reflect at least some of the visual information reflected by the first polarizing plate. Other various embodiments are also possible.