Spatially Variable Focal Length Optical Device for Field Curvature Compensation
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Solution Overview
Problem
Conventional imaging apparatuses with single-element optical devices suffer from field curvature, leading to distorted images and difficulty in maintaining focus across the image sensor, especially at high distortion rates and varying focal lengths, limiting their ability to emulate human eye resolution and requiring complex design and adjustment.
Innovation Solution
An imaging apparatus with an electrically controllable optical device having spatially variable focal length, comprising at least two electrode layers and a liquid crystal substance, where a control circuit adjusts focal lengths of different portions to compensate for field curvature, allowing for high distortion and improved focus adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional single-element optical devices are used, then the device structure is simple, but field curvature occurs causing image points off-optical axis to be focused before reaching the image sensor
Solution Approach 1:
The optical device is divided into multiple independently controllable optical elements arranged in an array, where each element can be individually actuated to adjust its focal length. This segmentation allows different regions of the optical device to have different focal lengths, compensating for field curvature effects while maintaining a relatively simple overall structure.
Solution Approach 2:
The optical device employs dynamic control through actuators that can real-time adjust the focal length of each optical element based on the object distance. This dynamic adaptability enables the system to maintain accurate focus across the entire image sensor plane for objects at varying distances, resolving the field curvature problem without requiring a complex fixed structure.
2Area of stationary object
If high distortion is produced by optical devices to capture requisite field of view, then the field of view is adequate, but emulating human eye resolution becomes difficult and design complexity increases
Solution Approach 1:
Different optical elements in the array are assigned different focal lengths according to their position, with peripheral elements having shorter focal lengths and central elements having longer focal lengths. This local differentiation allows the system to produce the required distortion for wide field of view while maintaining resolution characteristics that emulate human eye perception, without requiring overly complex design.
3Measurement precision
If focal length is increased for high image resolution, then image resolution is improved, but the field of view captured becomes very narrow at high readout rates
Solution Approach 1:
The optical device segments the imaging function across multiple elements with different focal lengths. Central elements use longer focal lengths for high-resolution central field of view, while peripheral elements use shorter focal lengths to capture the peripheral field of view. This segmentation allows the system to achieve both high image resolution and adequate field of view simultaneously.
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 solution enables the imaging apparatus to capture high-quality, distorted images that emulate human eye resolution, simplifies design, and effectively compensates for field curvature, allowing for accurate focus adjustment across varying distances.
Implementation Method 1
an optical device having a spatially variable focal length, wherein the optical device comprises at least two electrode layers and a liquid crystal substance
Implementation Method 2
a control circuit, coupled to the at least two electrode layers, to be employed to orient molecules of the liquid crystal substance in a given portion of the optical device in a given direction
Data Source
AI summary
An imaging apparatus including: an image sensor having a photo-sensitive surface; an optical device arranged on an optical path of light incidenting on the photo-sensitive surface, the optical device being electrically controllable to have a spatially variable focal length; and a processor configured to: generate and send a drive signal to the optical device to compensate for field curvature of optical device by adjusting focal lengths of different portions of the optical device to different extents, wherein a focal length of a first portion of the optical device is higher than a focal length of a second portion of the optical device surrounding the first portion; and control the image sensor to capture a distorted image of a real-world environment.