Liquid crystal cell assembly and method for detection enhancement
OwnerTigran Galstian, Van Vladimir Galstianinventors
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Abstract
Simple and cost-effective measurement of polarization components or the complete PSoL (the so-called Stokes parameters) is achieved without any mechanical movements or deformation by using liquid crystal elements. A transmission of a first polarization of light is greater than a transmission of a second orthogonal polarization of light and transmission of the second polarization is greater than 5%. In another of the different states, the device has different levels of transmission of the first and second polarizations of light. At least two orthogonal polarization component values characterizing the light can be resolved by comparing an intensity of light captured in a plurality of the different states.
Claims20
A light polarization modulation device comprising:
- at least one active liquid crystal element that, in response to a control signal, changes a propagation of light in a polarization-dependent manner in different states,
- wherein, in one of said different states, said device has a transmission of a first polarization of light greater than a transmission of a second orthogonal polarization of light and transmission of said second polarization is greater than 5%, and in another of said different states, said device has different levels of transmission of said first polarization of light and said second polarization of light than in said one of the different states;
- wherein at least two orthogonal polarization component values characterizing said light can be resolved by comparing an intensity of light captured in a plurality of said different states.
A polarization modulation and detection device comprising:
- a polarization modulation device comprising:
- at least one active liquid crystal element that, in response to a control signal, changes a propagation of light in a polarization-dependent manner in different states,
- wherein, in one of said different states, said device has a transmission of a first polarization of light greater than a transmission of a second orthogonal polarization of light and transmission of said second polarization is greater than 5%, and in another of said different states, said device has different levels of transmission of said first polarization of light and said second polarization of light than in said one of the different states;
- wherein at least two orthogonal polarization component values characterizing said light can be resolved by comparing an intensity of light captured in a plurality of said different states;
- at least one photodetector for receiving light passing through said at least one active liquid crystal element and producing an intensity signal;
- and
- a controller providing said control signal, receiving said intensity signal and providing at least one polarization state value characterizing said light by comparing said intensity signal in said different states.
A method of manufacturing product involving machine vision, the method comprising:
- providing a light polarization modulation and detection device comprising:
- a polarization modulation device comprising:
- at least one active liquid crystal element that, in response to a control signal, changes a propagation of light in a polarization-dependent manner in different states,
- wherein, in one of said different states, said device has a transmission of a first polarization of light greater than a transmission of a second orthogonal polarization of light and transmission of said second polarization is greater than 5%, and in another of said different states, said device has different levels of transmission of said first polarization of light and said second polarization of light than in said one of the different states;
- wherein at least two orthogonal polarization component values characterizing said light can be resolved by comparing an intensity of light captured in a plurality of said different states;
- at least one photodetector for receiving light passing through said at least one active liquid crystal element and producing an intensity signal;
- and
- a controller providing said control signal, receiving said intensity signal and providing at least one polarization state value characterizing said light by comparing said intensity signal in said different states;
- performing object detection using an image from said image sensor and said at least one polarization state value characterizing said light in said image from said image sensor;
- and
- using said object detection in quality control to reject or to release said product.
Dependencies are inferred from the claim text.