Variable Focal Length Exposure System for Alignment Film
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Solution Overview
Problem
Current exposure methods for forming alignment films in optical elements with varying focal lengths struggle to create continuous focal length changes without boundary regions, leading to issues like ghost images and multiple images, especially in high-resolution AR and VR applications.
Innovation Solution
An exposure system with a beam splitter, beam combiner, and focal point-variable focusing elements, including aspherical or cylinder lenses, that allows for continuous focal length changes and precise control of light interference to form alignment patterns without boundary regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional exposure methods are used to form alignment films, then the manufacturing process is simple, but boundary regions appear causing ghost images and multiple images
Solution Approach 1:
The patent applies the Dynamics principle by using a focusing element with continuously variable focal length instead of a fixed focal length lens. This allows the focal length to be dynamically adjusted during exposure, enabling the formation of alignment patterns with continuously varying single periods that eliminate boundary regions and prevent ghost images while maintaining manufacturing precision.
Solution Approach 2:
The patent implements the Parameter changes principle by varying the focal length parameter of the focusing element during the exposure process. This parameter change enables the single period of the alignment pattern to vary continuously across different regions, eliminating the discrete boundary regions that cause ghost images and multiple images in conventional methods.
2Manufacturing precision
If the single period decreases monotonically to vary focal length in plane, then the optical element acts as condenser or divergent lens, but the focal length becomes substantially constant over the entire surface
Solution Approach 1:
The patent uses a focusing element whose focal length can be dynamically varied during exposure, allowing precise control over the single period distribution. This dynamic control enables the creation of focal length distributions that are not limited to monotonic decreases, providing adaptability for different optical designs while maintaining manufacturing precision.
Solution Approach 2:
The patent employs periodic variation of the single period in the alignment pattern, where the single period increases and decreases periodically rather than monotonically. This periodic action creates corresponding periodic variations in focal length across the optical element surface, enhancing adaptability for various optical applications while maintaining precise focal length control.
3Ease of manufacture
If direct drawing exposure method or mask exposure method is used, then alignment pattern can be formed, but boundary regions are created leading to ghost images
Solution Approach 1:
The patent replaces static exposure methods (direct drawing or mask-based) with a dynamic exposure approach using a focusing element with continuously variable focal length. This dynamic method forms alignment patterns without discrete boundary regions, eliminating ghost images while maintaining ease of manufacture through automated focal length modulation during exposure.
Solution Approach 2:
The patent ensures continuity of useful action by using a focusing element that continuously varies its focal length during the exposure process. This continuous variation creates smooth transitions in the alignment pattern without abrupt boundary regions, eliminating ghost images while maintaining the ease of manufacture associated with conventional exposure methods.
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 the formation of alignment films and optical elements with continuous focal length changes, reducing ghost and multiple images, and improving image quality in high-resolution applications like AR and VR.
Implementation Method 1
a beam splitter element that splits light emitted from the light source
Implementation Method 2
a beam combiner element that includes a first surface and a second surface and emits light obtained by combining light transmitted through the first surface and light reflected from the second surface
Implementation Method 3
a focusing element that focuses light
Implementation Method 4
exposure system that generates interference light
Data Source
AI summary
Provided are an exposure system that simply manufactures an alignment film corresponding to an optical element where a focal length continuously changes, a method of forming an alignment film using the exposure system, a method of manufacturing an optical element using the alignment film, and an optical element. The exposure system includes: a light source; a beam splitter that splits light emitted from the light source; a beam combiner that combines the light split by the beam splitter and includes a first surface allowing transmission of light and a second surface reflecting light; focusing elements that is provided upstream of the beam combiner; and a polarization conversion element, in which one or more of the focusing elements have a focal length continuously changes in a direction orthogonal to an optical axis and away from the optical axis, and a ratio of a maximum value to a minimum value of the focal length is more than 1.1.