MEMS Alvarez Tunable Lenses for Fast Multi-Depth Image Capture
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Solution Overview
Problem
Existing light field microscopy systems suffer from low speed image capture or require a large number of image pixels to achieve suitable resolutions, and prior eye imaging techniques for eye-tracking are either slow or bulky, limiting their effectiveness in capturing images at multiple focal lengths.
Innovation Solution
Employing MEMS Alvarez tunable lenses with varying optical powers to focus light onto an image pixel array, combined with single-photon avalanche diodes (SPADs) and processing logic to capture images at different depths of field, enabling high-speed imaging of multiple object planes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If existing light field camera systems are used to capture images at various depths of field, then depth information is obtained, but image capture speed is slow and a large number of image pixels are required
Solution Approach 1:
The patent applies a tunable lens that can dynamically change its focal length to capture images at multiple depths of field. This dynamic optical system allows the camera to adjust focus rapidly between different depths, enabling high-speed capture of light field data without requiring a large number of pixels, thus resolving the contradiction between capture speed and pixel quantity requirements
Solution Approach 2:
The invention changes the optical parameters (focal length) of the lens to capture images at varying depths. By modulating the focal length parameter dynamically, the system can efficiently capture depth information across different planes using the same pixel array, thereby improving capture speed while maintaining adequate resolution without increasing pixel count
2Measurement precision
If a large number of image pixels are used to generate images with suitable resolutions, then image resolution is improved, but device complexity and cost increase
Solution Approach 1:
By using a tunable lens that dynamically adjusts focal length, the system captures high-resolution images at multiple depths without requiring a correspondingly large pixel array for each depth plane. This dynamic focusing capability maintains measurement precision across varying depths while avoiding the complexity increase that would result from using more pixels
Solution Approach 2:
The tunable lens serves multiple functions: it acts as both a focusing element and a depth-selective element. This multi-functionality allows a single optical system to achieve high-resolution imaging across multiple depth planes without requiring separate specialized components for each depth, thereby reducing overall device complexity while maintaining resolution
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 fast and efficient imaging of multiple object planes, such as the cornea, lens, and retina, facilitating improved eye-tracking by generating a light field image with detailed depth information.
Implementation Method 1
MEMS Alvarez tunable lenses, which provide varying optical powers by laterally shifting optical components
Implementation Method 2
drive the plurality of MEMS Alvarez tunable lenses to provide varying optical powers to focus light to the image pixels
Data Source
AI summary
An imaging device includes an image pixel array and a plurality of micro-electro-mechanical systems (MEMS) Alvarez tunable lenses disposed over regions of the imaging pixels. The MEMS Alvarez tunable lenses are configured to be adjusted to varying optical powers to focus image light to the plurality of imaging pixels at varying focus depths. Processing logic is configured to drive the plurality of MEMS Alvarez tunable lenses to provide varying optical powers to focus the image light to the imaging pixels during a plurality of image captures with the imaging pixels.