Curved Optical Element for Compact Head-Worn Display
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Solution Overview
Problem
Conventional imaging optics for display devices, such as those designed for head-worn glasses, face challenges in achieving a compact design due to the large optical path length and structural volume required for conventional optical components like lenses and prisms, making it difficult to create an ergonomically acceptable and aesthetically pleasing device.
Innovation Solution
The design incorporates an optical element with an entry surface that serves as a reflection surface via total internal reflection, eliminating the need for multiple lenses and prisms, and allowing for a compact structure by using a single optical element made of plastic or glass without air gaps, which can be in direct contact with the spectacle lens for permanent adjustment and reduced stray light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical components (lenses and prisms) are used to achieve the necessary optical path length and imaging function, then the imaging function is satisfied, but the construction volume becomes too large to be accommodated in the temple of spectacles
Solution Approach 1:
The patent merges multiple separate optical components (lenses and prisms) into a single integrated optical element. This optical element combines the functions of multiple components while reducing the overall construction volume, allowing the system to be accommodated in the temple of spectacles while maintaining the necessary optical path length and imaging function.
Solution Approach 2:
The patent employs a nested structure where multiple optical functions are embedded within a single optical element. The optical element contains integrated optical paths and functional zones that perform multiple operations (refraction, reflection, total internal reflection) in a compact, nested arrangement, significantly reducing the required volume.
2Reliability
If multiple separate optical components are used, then the optical path can be established, but the device complexity and number of components increase
Solution Approach 1:
The patent combines multiple optical components into a single integrated optical element, reducing the number of separate parts from multiple lenses and prisms to one unified component. This merging maintains all necessary optical paths and functions while significantly simplifying the overall device complexity.
Solution Approach 2:
The single optical element performs multiple functions that previously required separate components: refraction, reflection, total internal reflection, and image guidance. This multi-functional design eliminates the need for multiple specialized components, reducing device complexity while maintaining optical reliability.
3Ease of manufacture
If air gaps are present between optical components, then assembly is easier, but stray light and refraction issues increase
Solution Approach 1:
The patent merges optical components into a single monolithic optical element, eliminating air gaps between separate components. This integration removes the source of stray light and unwanted refraction that occurs at air-optical interface boundaries, while the single-piece construction maintains ease of manufacture through conventional optical fabrication techniques.
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 solution enables a compact and efficient imaging optics system that maintains necessary optical path length and imaging functionality, reducing the need for additional optical components and minimizing refraction and stray light, thus enhancing the ergonomics and aesthetics of the display device.
Implementation Method 1
the entrance surface serves as a reflective surface for guiding the generated image. Reflection can be achieved, for example, by means of total internal reflection.
Implementation Method 2
The imaging optics are designed to guide the generated image, which is fed to the optical element via the entrance surface, within the optical element, couple it into the spectacle lens, guide it to the output section, and couple it out via the output section
Data Source
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Figure 3~4
Figure 5~6
AI summary
The invention relates to an imaging optical unit for a display device that can be placed on the head of a user and generates an image, having an optical element (8) which has an entry surface (F1), and having a spectacle lens (3, 4) which has an input coupling section (15) and an output coupling section (16) spaced apart therefrom, wherein the imaging optical unit (7) is suitable to guide the generated image fed to the optical element (8) via the entry surface (F1) in the optical element (8), to couple said image from the latter into the spectacle lens (3, 4), in which the image is guided as far as the output coupling section (16) and is coupled out via the output coupling section (16) in order to generate a virtual image, wherein the optical element (8), besides the entry surface (F1), has at least one reflective surface (F2, F3, F4, F6; F2, F7, F6, F8), at which the generated image is reflected for guidance in the optical element (8), and an exit surface (F6), via which the generated image is coupled out of the optical element (8) and is guided to the output coupling section (15) of the spectacle lens (3, 4), wherein the entry surface (F1), the at least one reflective surface (F2, F3, F4, F6; F2, F7, F6, F8) and/or the exit surface (F6) is/are designed to be curved, such that the optical element (8) has an imaging property.