Optical Imaging Module With Quadratic Phase Mask
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Solution Overview
Problem
Conventional digital optical imaging systems with extended depth of focus face challenges such as high costs due to additional masks or aspheric lenses, complex design and fabrication processes, and increased complexity in image restoration due to asymmetric and larger point spread functions.
Innovation Solution
An optical imaging system with a specific longitudinal spherical aberration, characterized by a wave-front aberration equation, is used to achieve extended depth of focus, incorporating an optical imaging module, an array type detector, and an image restoration module, which converts captured light images into uniformly blurred images and restores them to clear images with depth of focus, utilizing standard axis symmetric aspheric lenses or whole-spherical lenses for cost-effectiveness and ease of integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional digital optical imaging systems use phase masks with special designs (cubic phase mask) to achieve extended depth of focus, then the depth of focus is improved, but the costs are high and mass production is not feasible due to free-form surface requirements
Solution Approach 1:
The patent changes the phase mask design from a cubic phase function to a quadratic phase function, fundamentally altering the mathematical form to enable manufacturability. This parameter change allows the use of standard rotationally symmetric aspheric surfaces that can be mass-produced using conventional optical manufacturing techniques, while still achieving extended depth of focus through the modified phase transformation.
Solution Approach 2:
The patent replaces expensive, difficult-to-manufacture free-form cubic phase masks with inexpensive, easily manufacturable quadratic phase masks using standard aspheric lenses. These simpler components can be produced at low cost through conventional optical fabrication processes, making the technology economically viable for mass production in consumer electronics.
2Reliability
If conventional digital optical imaging systems use additional masks or free-form aspheric lenses for extended depth of focus, then the depth of focus is improved, but the design and fabrication process is further complicated
Solution Approach 1:
The patent integrates the extended depth of focus function directly into the objective lens by incorporating a quadratic phase function into its design. This allows the objective lens to simultaneously perform both imaging and depth extension functions, eliminating the need for separate phase masks or additional optical components, thereby simplifying the overall system design and fabrication.
Solution Approach 2:
The patent combines the depth extension function with the primary imaging function by integrating the quadratic phase modulation into the objective lens itself. This merging of functions reduces the number of separate components needed, simplifies the optical train, and reduces alignment complexity compared to using separate phase masks.
3Reliability
If conventional digital optical imaging systems use asymmetric and larger point spread function for extended depth of focus, then the depth of focus is improved, but the image restoration process is made more complex
Solution Approach 1:
The patent actually addresses this by creating a symmetric point spread function through the use of rotationally symmetric quadratic phase masks, as opposed to the asymmetric point spread function produced by cubic phase masks. This symmetry simplifies the image restoration process by making the point spread function invariant to rotational transformations, reducing the complexity of deconvolution algorithms.
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 system efficiently extends the depth of focus, maintains a uniform energy distribution of the point spread function, and achieves a higher Strehl ratio, simplifying image restoration and reducing costs by using symmetric lenses, making it suitable for large noise conditions and mass production.
Implementation Method 1
The optical imaging module has a specific longitudinal spherical aberration corresponding to the depth of focus
Implementation Method 2
The array type detector is coupled to the optical imaging module for obtaining an image
Data Source
AI summary
An optical imaging system with extended depth of focus is provided. The optical imaging system includes an optical imaging module, an array type detector and an image restoration module. The optical imaging module has a specific longitudinal spherical aberration corresponding to the depth of focus. The array type detector is coupled to the optical imaging module to obtain a image via the specific longitudinal spherical aberration provided by the optical imaging module. The image restoration module is coupled to the array type detector, wherein the array type detector converts the obtained image to a digitalized image and the image restoration module receives the digitalized image and performs an image restoration operation to the digitalized image to form an image with extended depth of focus.