Optimizing performance parameters for switchable polymer dispersed liquid crystal optical elements
First Claim
1. A method for switching a holographic diffraction grating via a switching field between a first diffraction efficiency and a second diffraction efficiency comprising:
- orienting the holographic diffraction grating such that an internal angle of p-polarized light incident thereon satisfies the following condition for a switching field of zero, wherein θ
ρ
is the angle of incidence of a reference wave of the incident light and ε
xx(1) and ε
zz(1) are the x and z components of the modulation of the dielectric tensor for a material comprising the holographic diffraction grating and the holographic diffraction grating has a first diffraction efficiency; and
applying a switching field greater than zero in order to switch the holographic diffraction grating to a second diffraction efficiency.
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Abstract
Described herein are the materials, mechanisms and procedures for optimizing various performance parameters of HPDLC optical devices in order to meet differing performance requirements. These optimization tailoring techniques include control and independent optimization of switchable HPDLC optical devices to meet the demanding requirements of anticipated applications for, inter alia, the telecommunications and display industries. These techniques include optimization of diffraction efficiency, i.e., index modulation, polarization dependence control, haze, cosmetic quality, control of response and relaxation time, voltage driving for on and off switching, and material uniformity. This control and independent optimization tailors properties of switchable HPDLC optical devices according to the specific requirements of the application of the switchable HPDLC optical device. The invention disclosed herein retains the desirable attributes of the multi-functional acrylate system for forming HPDLC optical devices, but adds new materials to the acrylate system and/or new process control to the recording to optimize performance parameters as may be needed for specific applications. This results in high optical quality switchable holograms with good diffraction efficiency and low, stable switching voltage.
200 Citations
20 Claims
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1. A method for switching a holographic diffraction grating via a switching field between a first diffraction efficiency and a second diffraction efficiency comprising:
-
orienting the holographic diffraction grating such that an internal angle of p-polarized light incident thereon satisfies the following condition for a switching field of zero, wherein θ
ρ
is the angle of incidence of a reference wave of the incident light and ε
xx(1) and ε
zz(1) are the x and z components of the modulation of the dielectric tensor for a material comprising the holographic diffraction grating and the holographic diffraction grating has a first diffraction efficiency; andapplying a switching field greater than zero in order to switch the holographic diffraction grating to a second diffraction efficiency. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for switching an inverse mode holographic polymer dispersed liquid crystal grating, the method comprising the steps of:
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orienting a holographic diffraction grating so that an internal incident angle of p-polarized light at zero field satisfies wherein θ
ρ
is the angle of incidence of a reference wave of the incident light and ε
xx(1) and ε
zz(1) are the x and z components of the modulation of the dielectric tensor for a material comprising the holographic diffraction grating.- View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for switching an inverse mode holographic polymer dispersed liquid crystal grating, the method comprising the steps of:
-
orienting a holographic diffraction grating so that an internal incident angle of p-polarized light at zero field satisfies wherein θ
ρ
is the angle of incidence of a reference wave of the incident light and δ
xx(1) land ε
zz(1) are the x and z components of the modulation of the dielectric tensor for a material comprising the holographic diffraction grating, wherein when a field is applied, ∈
xx(1) increases while ∈
zz(1) decreases.
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Specification