Birefringent Device for Ring-Shaped Side Peak Attenuation
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Solution Overview
Problem
Optical systems and cameras struggle to produce pleasant bokeh due to uncontrolled ring-shaped side peaks in out-of-focus point spread functions, which are influenced by optical aberrations, leading to undesirable blurred image edges.
Innovation Solution
Incorporating a birefringent device in the optical path of the lens unit, which selectively attenuates the ring-shaped side peak in the out-of-focus point spread function by varying polarization-dependent phase alterations, minimizing side peaks while maintaining in-focus image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a lens unit is designed to limit depth of focus, then bokeh effect is enhanced, but out-of-focus portions appear with ring-shaped side peaks causing unpleasant blurred edges
Solution Approach 1:
A birefringent device is introduced as an intermediary element in the optical path between the lens unit and the image sensor. This device selectively attenuates the ring-shaped side peak in the out-of-focus point spread function by introducing polarization-dependent phase alterations, thereby improving bokeh quality without changing the lens unit itself
Solution Approach 2:
The birefringent device changes the polarization state parameters of light passing through the optical system. By varying the polarization-dependent phase alteration, the device selectively modifies the out-of-focus point spread function to reduce ring-shaped side peaks while maintaining in-focus image quality
2Manufacturing precision
If additional lenses are added to correct optical aberrations, then image quality improves, but device complexity and weight increase
Solution Approach 1:
The patent replaces additional mechanical lens elements with a birefringent device that uses polarization-dependent phase modulation to correct optical aberrations. This substitution reduces the number of physical lenses required while achieving similar or better image quality control
3Shape
If apodization masks are used to control bokeh, then ring-shaped side peaks are reduced, but light loss occurs
Solution Approach 1:
The birefringent device introduces polarization-dependent phase transitions in the optical path, creating different phase shifts for different polarization states. This allows selective attenuation of ring-shaped side peaks through interference effects without absorbing light, thereby avoiding the light loss associated with apodization masks
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 birefringent device effectively reduces ring-shaped side peaks by at least 25% in the out-of-focus point spread function, resulting in a more pleasant bokeh without additional lenses or loss of light, thus enhancing image quality without adverse impact on autofocus systems.
Implementation Method 1
A birefringent device in an optical path of the optical system is adapted to selectively attenuate the ring-shaped side peak in the out-of-focus point spread function of the lens unit
Implementation Method 2
The phase alteration attenuates a ring-shaped side peak in the out-of-focus point spread function of the lens unit by at least 25 percent
Data Source
AI summary
An optical system (110) includes a lens unit (112) with a plurality of lenses. An out-of-focus point spread function of the lens unit (112) includes an annular intensity distribution with at least one ring-shaped side peak at a radial distance to a center point. A birefringent device (115) in an optical path of the optical system (110) is adapted to selectively attenuate the ring-shaped side peak in the out-of-focus point spread function of the lens unit (112).