Rotationally Symmetric Phase Plate with Asymmetric Ring Zones
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Solution Overview
Problem
Conventional optical phase masks are non-rotationally symmetric, making them incompatible with many rotationally symmetric optical lenses, which limits the design error tolerance and results in an inability to achieve a deep depth of field or focus due to uneven light flux distribution along the optical axis.
Innovation Solution
A rotationally symmetric optical component with multiple ring zones demarcated by concentric circles, featuring concave or convex cross-sections that are asymmetric in the radial direction, ensuring uniform light distribution and compatibility with axially symmetric optical lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a non-rotationally symmetric optical phase mask is used to expand depth of field, then the depth of field is expanded, but the permissible range of design error is reduced due to the need for both axial displacement and rotational adjustment
Solution Approach 1:
The patent applies asymmetry by introducing a asymmetric shape parameter 'a' in the ring zone configuration, where the ring zone has different radial widths at different angular positions. This asymmetric design allows the optical phase mask to maintain rotational symmetry compatibility with standard optical lenses while achieving uniform PSF distribution along the optical axis, thereby expanding depth of field without requiring precise rotational alignment or reducing design error tolerance.
2Duration of action of stationary object
If an axially symmetric optical phase mask with multiple ring zones is used to make PSF distribution uniform, then the depth of focus is enlarged, but the total amount of light flux through the outer part is larger than through the inner part, preventing equalization of PSF
Solution Approach 1:
The patent applies local quality by varying the radial width of the ring zone as a function of angular position. Specifically, the ring zone has a first radial width at a first angular position and a second radial width at a second angular position, where these widths are different. This local variation in ring zone dimensions compensates for the uneven light flux distribution, allowing equalization of PSF across different regions while maintaining overall rotational symmetry.
Solution Approach 2:
The patent changes the geometric parameters of the ring zone by introducing an asymmetric shape parameter 'a' that controls the radial width variation. By adjusting this parameter and other dimensional parameters, the design achieves a balance between light flux distribution and PSF uniformity, enabling both deep depth of focus and equalized light distribution without requiring complex multi-component systems.
3Reliability
If conventional optical phase masks are used, then phase modulation is achieved, but rotational symmetry compatibility with optical lenses is lost, requiring additional adjustment mechanisms
Solution Approach 1:
The patent achieves universality by designing an optical phase mask that simultaneously maintains rotational symmetry compatibility with standard optical lenses and provides the necessary phase modulation for depth of field extension. The ring zone configuration with varying radial widths creates a system that works with conventional lens designs without requiring special alignment procedures or additional adjustment mechanisms, making it universally applicable to standard optical systems.
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 configuration allows for a deep depth of field or focus, reducing the need for rotational adjustments and enhancing design accuracy, while maintaining image quality with minimal blurring across the focus range.
Implementation Method 1
an optical phase mask for modulating a phase of light is disposed in an optical system
Implementation Method 2
one ring zone has a concave or convex cross section, and is divided into an inner part and an outer part by a circle having maximum values or minimum values of the convex/concave
Data Source
AI summary
To provide an optical component (phase plate) capable of acquiring an image of a deep depth of field or focal position, and an imaging device using it. What is provided is the optical component that includes multiple ring zones demarcated by multiple concentric circles, and is configured to be rotationally symmetric to a center of the concentric circles. Cross sections of the ring zones on a plane being parallel to a direction perpendicular to the concentric circles and including the center have concave or convex shapes. Each of the concave or convex shapes of the cross sections of the ring zones is asymmetric to a centerline of a width of each of the ring zones in a radial direction of the concentric circles.