Light protection optical systems

Abstract

A light protection optical system for attenuating environment light includes a window disposed between a viewer and an environment having environment light within the visible spectrum. The window includes a window polarizer that preferentially attenuates a first polarization component (P1) of environment light and preferentially transmits a second polarization component (P2) of environment light to produce a polarized environment light. An electronically adjustable polarizer (EAP) is disposed between the viewer and the window, wherein the EAP is configured to receive the polarized environment light. When electronically adjusted to produce a non-attenuating state, the EAP transmits the polarized environment light as eye-entering light having a first environment light transmittance. When electronically adjusted to produce an attenuating state, the EAP attenuates the transmission of the second polarization component (P2) of the polarized environment light to produce eye-entering light having second environment light transmittance that is at least 20% lower than the first environment light transmittance.

Description

LIGHT PROTECTION OPTICAL SYSTEMSCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to, and any other benefit of, U.S. Provisional Patent Application Serial No. 63 / 627,079, entitled LIGHT PROTECTION OPTICAL DEVICES, filed January 31, 2024, the entire disclosure of which is fully incorporated herein by reference.TECHNICAL FIELD

[0002] The present disclosure relates to optical systems that provide protection from high intensity radiation, and in particular, to light protection optical systems capable of blocking bright flashes of intense broadband light or laser light.BACKGROUND

[0003] Variable transmission optical devices, e.g., glasses, goggles, visors, windows, sensors, filters, cameras, or the like, that can quickly change between a high-transmission “clear” state and a low-transmission “dark” state have many advantages over fixed transmission optical devices. An especially useful feature is the ability to make this quick change occur on demand, whether manually, at the touch of a button by the user, or automatically, under the control of a light sensor and an electronic circuit.

[0004] Optical devices can potentially offer protection from high-intensity light, e.g., from narrow beam light sources such as lasers or bright flashes such as from bright explosions or stun grenades. For example, the military, police, first responders, pilots and others can face threats from high-intensity light wielded by hostile persons or devices. Defending against high-intensity light has been difficult and solutions to date have been largely unsatisfactory. For example, a common approach (for green lasers) has been simply to provide a static green-light absorbing strip at a top portion of a face shield. This only provides protection if the person wearing it has their head properly angled. Furthermore, the system will continue to block that region of the spectrum regardless of the presence or absence of the threat. This can lead to color distortions which may not meet the optical requirements for some uses.

[0005] In the case of pilots, a static tinted film that blocks the green laser is undesirable because it can also dim aviator vision and filter out cockpit displays (which commonly emitgreen light), and additionally, impair the pilot’s ability to properly view PAPI (Precision Approach Path Indicator) or VASI (Visual Approach Slope Indicator) lights which require red / white or red / green differentiation.

[0006] In addition, previous technologies do not address bright light flashes which may have a broadband spectrum. Simply shielding a viewer’s eyes cuts off all other visual information, e.g., from a cockpit display.

[0007] Thus, there is a need to provide an optical system that can protect a user’s eyes against intense light while maintaining the ability to see other visual information from devices (displays, control panels, or the like) associated with the environment occupied by the user.SUMMARY

[0008] Described herein is a light protection optical system for attenuating environment light that includes a window disposed between a viewer and an environment having environment light within the visible spectrum. The window includes a window polarizer that preferentially attenuates a first polarization component (Pl) of environment light and preferentially transmits a second polarization component (P2) of environment light to produce a polarized environment light. An electronically adjustable polarizer (EAP) is disposed between the viewer and the window, wherein the EAP is configured to receive the polarized environment light. When electronically adjusted to produce a non-attenuating state, the EAP transmits the polarized environment light as eye-entering light having a first environment light transmittance. When electronically adjusted to produce an attenuating state, the EAP attenuates the transmission of the second polarization component (P2) of the polarized environment light to produce eye-entering light having second environment light transmittance that is at least 20% lower than the first environment light transmittance.

[0009] Also described herein is a light protection optical system for attenuating environment light that includes a window disposed between a viewer and an environment having environment light within the visible spectrum that includes broadband radiation and narrowband radiation, the narrowband radiation having a peak wavelength. The window includes at least one narrow band window polarizer that preferentially attenuates a first polarization component (Pl) of environment light at the peak wavelength and preferentially transmits a second polarization component (P2) of environment light at the peak wavelength to produce a partially polarized environment light. An electronically adjustable polarizer (EAP) is disposed between the viewerand the window and configured to receive the partially polarized environment light. When electronically adjusted to produce an attenuating state, the EAP blocks at least 50% of the partially polarized environment light at the peak wavelength, alternatively at least 80%, and transmits at least 20% (alternatively at least 25%) of the partially polarized environment light at one or more wavelengths at least 50 nm away from the peak wavelength.

[0010] In some embodiments, the EAP is further configured to receive at least one display light from one or more information display systems, wherein the display light includes at least a first polarization component (Pl) and optionally, a second polarization component (P2). When in the attenuating state, the EAP preferentially attenuates the optional second polarization components (P2) of display light while preferentially transmitting the first polarization component (Pl) of the display light such that at least 10% of display light incident on the EAP is transmitted as eye-entering display light.

[0011] In some embodiments, the EAP may be incorporated into eyewear, goggles, or a visor worn by the viewer. Also contemplated herein are methods of using any of the optical systems described herein to attenuate high intensity light originating in the environment, where the method includes switching the EAP from a non- attenuating state to an attenuating state.BRIEF DESCRIPTION OF DRAWINGS

[0012] FIGS. 1A-1D are schematic cross-sectional views of non-limiting examples of a light protection optical system for protection against high-intensity light in its non-attenuating state (FIGS. 1A and 1C) and attenuating state (FIGS. IB and ID).

[0013] FIGS. 2A and 2B are schematic cross-sectional views of a non-limiting example of another light protection optical system in its non-attenuating state (FIG. 2A) and attenuating state (FIG. 2B).

[0014] FIGS 3A - 3C are cross-sectional views of an EAP used in some non-limiting examples of a light protection optical system.

[0015] FIGS 4A - 4D are cross-sectional views of another EAP used in some non-limiting examples of a light protection optical system.

[0016] FIGS. 5A and 5B are cross-sectional views of a non-limiting example of another optical system in its non- attenuating state (FIG. 5A) and attenuating state (FIG. 5B).

[0017] FIGS. 6A and 6B are schematic diagrams of some non-limiting examples of electronic polarization rotators.

[0018] FIGS. 7 and 8 show some non-limiting examples of absorbance or reflectance spectra for window polarizers and EAPs.DETAILED DESCRIPTION

[0019] Note that various embodiments are often described with reference to lasers, but this is simply for convenience and such embodiments also generally apply to other polarized high intensity narrowband radiation sources. For example, the devices and methods of the present application may protect a user or a device from an LED, a surface-mounted diode (SMD), or the like. Further, various embodiments are often described with respect to a bright or explosive flash, but this is simply for convenience and such embodiments also generally apply to other broadband high intensity light sources, whether flash or continuous.

[0020] Regarding various concepts described herein relating to polarization rotators, electronically adjustable polarizers, liquid crystal devices, guest-host systems, and laser protection, reference is made to U.S. Patent Nos. 9,304,333, 11,500,255, 12,117,701, PCT Publication No. 2023 / 086426, and U.S. Application Publication No. 2024 / 0077777, the entire contents of each are incorporated herein by reference for all purposes.

[0021] A few descriptions and definitions are provided below to aid in the discussion of various embodiments. Wherever any conflict may exist, the description found in the embodiments supersedes.

[0022] Unless specifically defined otherwise herein, the definitions for optical parameters such as linear, circular and unpolarized light are the same as those in “Principles of Optics Electromagnetic Theory of Propagation, Interference and Diffraction of Light”, Max Born, et al., Cambridge University Press; 7th edition (October 13, 1999). Similarly, all liquid crystal terminology which is not specifically defined herein is to have the definition as used in Liquid Crystals Applications and Uses, vol.3, edited by B. Bahadur, published by World Scientific Publishing Co. Pte. Ltd., 1992 (“Bahadur”).

[0023] An “absorptive polarizer” as used herein is a polarizer that is configured to absorb a selected polarization of light (e.g., narrow band or wideband absorption, depending on the configuration). In some cases, an absorptive polarizer may be characterized by two axes, anabsorptive axis and a transmissive axis, which are at right angles to each other (or in the case of circularly polarized light, the opposite-handed circularly polarization). For case of description, the two polarization directions of light are referred to as a first polarization (Pl) and a second polarization (P2) - wherein Pl and P2 can be linear, circular or any other type of polarization. The polarization of the light that is parallel to the axis of the absorptive polarizer is absorbed more than the orthogonal (or opposite) polarization component. For example, an “absorptive polarizer with an axis in the x-direction” means that the polarizer will substantially absorb the x- direction polarization of light while substantially allowing y-polarization to propagate (or vice versa). It should be noted that absorptive circular polarizers may be constructed by using a linear polarizer in combination with a quarter wave retarder. Once light is polarized by the polarizer, the quarter wave plate induces a p / 2 phase retardation which turns a linear polarization to a circular polarization. In some cases, an absorptive polarizer may include a liquid crystal host and a dichroic light- absorbing guest provided with a particular alignment.

[0024] A “reflective polarizer” as used herein is a polarizer that will reflect a selected polarization of radiation more than the other. For example, a “reflective polarizer with a reflective axis in the Pl -direction” means that the reflective polarizer will reflect the Pl -direction or component polarization of incident light more than the other P2-direction polarization (or vice versa). In some cases, a reflective polarizer will reflect right-handed circularly or elliptically polarized radiation more than the left-handed component which may be transmitted (or vice versa). A reflective polarizer may be “passive / static” or “active”. In some cases, a reflective polarizer may include a cholesteric liquid crystal (CLC) material. In others, a stack of birefringent material can provide reflective polarizer properties.

[0025] A “passive polarizer” or “static polarizer” refers to a polarizer whose properties are generally fixed and not controllable, e.g., by an electric field. A passive polarizer may be an absorptive polarizer or a reflective polarizer.

[0026] An “active polarizer” or an “electronically adjustable polarizer (“EAP”)” or an “electronic Polarizer on Demand” (“e-POD”) refers to a polarizer that can in some way alter the attenuation (e.g., by absorption or reflection) of a selected polarization of light depending on an applied voltage. In some embodiments, when in a non-attenuating state (which may also be referred herein to as a non-activated state or a transmissive state), an active polarizer will not preferentially attenuate (absorb or reflect) either polarization and will transmit light of bothpolarizations. When in an attenuating state (which may also be referred to herein as an activated state or a less transmissive state, the polarizer will preferentially absorb or reflect one polarization and may substantially transmit light of the other polarization. A controller coupled with the active polarizer controls the polarization through the applied voltage (V). In one embodiment, the polarizer is operated in an ON or OFF state. In other embodiments, the polarizer can be set to apply a variable polarization absorption / reflection level using the controller. In some examples, the polarization level of the active polarizer is selected by controlling the voltage (V) applied to the active polarizer. Thus, the device can further include a controller for application of voltage to the electronically adjustable polarizer. Note that in some examples, the active polarizer is in its non- attenuating state when no voltage is applied (V=0) and attenuating when a voltage is applied (V=l). In other examples, the reverse may be true, i.e. the EAP is non-attenuating when a voltage is applied (V=l) and attenuating when no voltage is applied (V=0). In some cases, an EAP may include a graduated active absorptive polarizer as described in 11,500,255, which is incorporated by reference, wherein the intensity of absorptive polarization changes across the device.

[0027] Polarizers (passive, active, absorptive, reflective... etc.) can generally be characterized by an extinction ratio or similar metrics that provide a general measure of how selective the polarizer is at transmitting or blocking one polarization relative to the orthogonal polarization. Herein, when for example it is said that a first polarization (Pl) is “preferentially attenuated” or “substantially attenuated” relative to an orthogonal second polarization (P2) which is “preferentially transmitted” or “substantially transmitted”, it is meant that the ratio of transmittance of P2 (%Tp2) to the transmittance of Pl (%Tpi) (herein, “contrast ratio”) is at least 4:1, but alternatively at least 5:1, 7:1, 10:1, or even higher. Such measurement may be based on transmittance at the polarizer’s wavelength of highest absorbance or reflectance (peak contrast ratio), or alternatively, on an integrated transmittance measured across the wavelength range on which the polarizer is intended to act, i.e., absorb or reflect (integral contrast ratio). Integral contrast ratio may in some cases be measured based on the full-width half-max of the absorbance or reflectance.

[0028] An “active polarization rotator” or an “electronic polarization rotator” refers to a device where alteration of an applied voltage to the device alters the polarization properties of incident polarized radiation. In some embodiments, it may be used as part of an EAP system. Forexample, an electronic polarization rotator may alter the direction of one or two linearly polarized components of the incoming light by a value in a range of 1 to 90 degrees, or any degree therebetween such as more than 80, 70, 60, 50, 40, and so on) changing it so that light exiting the polarizer rotator is changed from a substantially first direction to a substantially second direction polarization within a desired wavelength region. Thus, for example, polarized light having polarization angle 0i entering the polarizer rotator will be turned into polarized light having polarization angle 02. In some cases, the rotator may turn linearly polarized light to elliptical / circular- polarized light. The electronic polarization rotator may function in various ways: in some examples, polarization rotation occurs when the rotator is in the energized (V is not 0, or V=l) state, in other examples, polarization rotation occurs when the rotator or device is in an unenergized (V=0) state.

[0029] “Narrow band” absorption (or reflectance) as used herein, is defined as a spectral absorption band width (or reflectance band width) with a Full Width at Half Max (FWHM) that is less than or equal to 175 nm, or alternatively less than or equal to 165 nm, 155 nm, 120 nm, lOOnm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, 20 nm, or 10 nm where the entire spectral absorption band is typically measured within the visible region of 400 - 700 nm, or alternatively 380 nm - 780 nm.

[0030] ‘ ‘Ultra-Narrow Band” absorption (or reflectance) is a subset of “narrow band” and as used herein is defined as a spectral absorption band width (or reflectance band width) with FWHM that is less than or equal to 88 nm, or alternatively less than or equal to 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30nm, 20 nm, or 10 nm or less where the entire spectral absorption band is typically measured within the visible region of 400 - 700 nm, or alternatively 380 nm - 780 nm.

[0031] ‘ ‘Wide band” absorption (or reflectance) as used herein, may refer to a spectral absorption band width (or reflectance) that is greater than 175 nm, and preferably greater than 180 nm, 185 nm, 190 nm, 195 nm or 200 nm. In some examples, much or all of the absorption band is contained within the range of visible wavelengths, i.e., 380 nm - 780 nm, or alternatively 400 - 700 nm. In other examples, the absorption band may cover other non-visible regions of the electromagnetic spectrum (including UV or IR).

[0032] ‘ ‘Narrowband radiation” refers to radiation incident on the present optical device having a wavelength bandwidth less than 88 nm, alternatively less than 80, 70, 60, 50, 40, 30, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 nm. In some cases, bandwidth may correspond to a full-width-at-half-max (FWHM) of a spectrum of relative radiant power vs. wavelength. “Ultra-narrowhand radiation is a subset of narrowband radiation and refers to the incident light having a bandwidth of less than 40 nm, alternatively less than 30, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 nm.Narrowband radiation, which may optionally be ultra-narrowband radiation, may in some cases include light produced from a laser (laser radiation or laser light), surface-mounted diodes (SMDs) or some LEDs and the like.

[0033] ‘ ‘Broadband light” refers to radiation having a wavelength bandwidth of at least 88 nm, alternatively, at least 100 nm, 175 nm, or 250 nm, e.g., measured as a FWHM of a spectrum of relative radiant power vs. wavelength. In some cases, the spectrum of broadband light includes more than a single band, but there is significant intensity (e.g., at least 50% of a peak intensity) across at least a 100 nm portion of the spectrum. In some cases, broadband light includes visually discernible wavelengths across most or all of the visible light spectrum. In some cases, broadband light may include non-visible regions of the electromagnetic spectrum, e.g., UV or IR.

[0034] “High intensity” light or radiation refers to broadband light or narrowband radiation capable of disrupting the human visual system. For example, high-intensity light is that which may cause startle, distraction, glare, flash blindness, afterimage, photosensitivity, thermal or hemorrhagic lesion, eye damage, vertigo, disorientation, photophobia, headaches, muscle spasms, convulsions, or epileptic seizures. With respect to narrowband radiation, high-intensity light may have an irradiance equivalent to X*MPE, where X is 0.1, 0.5, 0.7, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10, and MPE is the Maximum Permissible Exposure according to ANSI Z136.1. In some cases, high-intensity light may have an irradiance of at least 10’6W / cm2, alternatively at least 10’4W / cm2, 10'3W / cm2, 10'2W / cm2, or lO^ W / cm2.

[0035] “Optical Density” or OD generally refers to the apparent absorbance of radiation measured at a particular wavelength, e.g., at a peak dye absorption wavelength or a peak narrowband radiation wavelength. Percent transmittance (%T) is related to the overall OD at the particular' wavelength through:%T = 10< OD)x 100%.

[0036] ‘ ‘Polarizer” refers to a material, layer, or component that preferentially absorbs or reflects one polarization (e.g., Pl) of incident light more than the other polarization (e.g., P2).

[0037] “Transmission” and “Transmittance” are used interchangeably and mean the percentage of light that is transmitted through a mixture, layer, or device, and which may be referred to herein as a %T. Since broadband radiation includes a range of wavelengths, any reference to transmittance of broadband radiation herein generally refers to the integrated or average transmittance across the visible spectrum unless otherwise noted.

[0038] “Photopic transmittance” or “photopic transmission” refers to the percent transmission of visible light weighted by the spectral response of the day-adapted human eye.

[0039] ‘ ‘Visible light” or the “visible spectrum” refers to a wavelength range of 400 - 700 nm, or alternatively, about 380 nm to about 780 nm.

[0040] FIGS. 1A-1D are schematic cross-sectional views of non-limiting examples of an optical system for protection against high-intensity light in its non- attenuating state (FIGS. 1A and 1C) and attenuating state (FIGS. IB and ID). The optical system of FIGS. 1C and ID is like that for FIGS. 1A and IB, but further illustrates how it may be used in conjunction with display components. For additional perspective, arbitrary XYZ axes are also illustrated. First (Pl) and second (P2) polarization components are also noted, where Pl is generally parallel to the y axis and P2 is generally parallel to the x axis, but such directions are arbitrary and provided simply for illustrative purposes. P2 is generally orthogonal to Pl. For clarity, not all of the part numbers are shown in FIGS. 1B / 1D relative to FIGS. 1A / 1C, but the features are the same unless otherwise noted. Optical system 100 includes a window 110 disposed between a viewer 101 and an environment 181 (or first zone) to be viewed. In some embodiments, part 101 may in particular represent a viewer’s eyes. In some cases, environment 181 may correspond to an “outdoor” ambient environment and the term “window” may correspond to a vehicle windshield, an aircraft canopy, a building window, or the like. Alternatively, window 110 may in some cases correspond to a helmet face shield, a riot shield, or other protective shield, or the like.Environment 181 is not necessarily outdoors and in some cases may be within a building or structure.

[0041] Window 110 may include a substrate or windowpane 111 and a window polarizer 112 which may be a static polarizer, a photochromic or photochromic-dichroic polarizer that activates upon exposure to UV light, or an active polarizer. In the present embodiment, window polarizer 112 absorbs or reflects light polarized along the y-axis (Pl) and transmits light polarized along the x-axis (P2). Note that any reference to “x” and “y” polarizations are arbitraryand simply serve to illustrate the general operation of the optical system. Note that window 110 can “include” a window polarizer 112 in numerous ways and the term is intended convey any functional association. For example, the window polarizer may be provided on an outer surface of the window pane (as shown), be provided on an inner surface, be provided within the window pane (or between multiple panes), be a unitary structure where the pane and polarizer are one, or be spaced apart from the window pane so long the window polarizer occupies most or all of the viewer’s expected optical path for viewing the environment. In some cases, the window polarizer has a surface area that is smaller than the total windowpane - as necessary based on its functionality.

[0042] Environment 181 (first zone) may include various types of environment light within the visible spectrum. Some environment light is safe for viewing, but some other environmental light may be high-intensity light (from bright flashes, lasers, or the like) that is disruptive or even hazardous to the viewer. In FIGS. 1A and 1C, environment light that is safe for viewing may include broadband light 160, which may correspond to non-threat multi-color light from an ambient scene. Broadband light 160 is generally not highly polarized and may include both Pl and P2 polarization components (although in some cases, one component may be stronger than the other). The broadband light 160 may, for example, include visible light. Broadband light 160 is received by window polarizer 112 which attenuates a first polarization (Pl - in this case, along the y-axis) and substantially transmits a second polarization (P2- in this case, along the x- axis) to produced polarized broadband light 162 (polarized environment light) that is transmitted into an intermediate region (second zone) 182. In some embodiments, window polarizer 112 may be characterized as having a wide band absorption (or reflection) and may block the first polarization component of light across a substantial portion or all the visible spectrum, or even beyond (e.g., in the IR or UV). Since the y-axis (Pl) polarization component has been eliminated, the intensity of polarized broadband light 162 is lower than broadband light 160 (in some cases by ~ 50%), but the environment is generally still readily viewable.

[0043] An electronically adjustable polarizer (EAP) 140 which is configured (electronically adjustable) to switch between a non-attenuating (or transmissive or non-activated) state, and an attenuating (or less transmissive or activated) state is disposed between viewer 101 and window 110 and receives the polarized broadband light 162. There are numerous options for the construction and operation of the EAP, which may be reflective or absorptive.

[0044] In the non-limiting examples shown in FIGS. 1 A & 1C, EAP 140 is an absorptive electronic polarizer (or “c-POD”) in its non-attenuating state. In its non-attenuating state, EAP 140 generally does not preferentially absorb either polarization, and instead, can substantially transmit light of both polarizations. Note that the arrow within EAP 140 is pointed along the z axis. Throughout the present disclosure, this is intended to represent the case where both polarizations Pl and P2 are substantially transmitted.

[0045] For example, the EAP in its non-attenuating state may transmit at least 10% of incident visible light of either polarization, alternatively at least any of 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%. In some embodiments, EAP 140 in its non-attenuating state, is characterized by a photopic transmission of at least 10%, alternatively at least any of 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or 95%. As such, polarized broadband light 162 is substantially transmitted into a near-eye region between the viewer and the EAP (third zone) 183 as eyeentering broadband light 163a which is received by the viewer 101 (in particular, the viewer’ s eyes). EAP 140 may in some cases be incorporated into eyewear, goggles, a visor, or the like.

[0046] In some embodiments, in its non- attenuating state, at least 10% of incident broadband light 160 is transmitted to the viewer as eye-entering broadband light 163a, alternatively at least any of 20%, 30%, 40%, 45%, 46%, 47%, 48%, 49% or 50%.

[0047] In some embodiments, in its non- attenuating state, at least 10% of polarized broadband light 162 incident on the EAP is transmitted to the viewer as eye-entering broadband light 163a, alternatively at least any of 20%, 30%, 40%, 45%, 46%, 47%, 48%, 49% or 50%. This metric may optionally be referred to as the “first environment light transmittance”.

[0048] In some embodiments, the second zone may further include display light produced from an information display system such as a console, a control panel, an AR display, or the like. The display light is also intended for viewing by the viewer. For example, FIG. 1C includes AR display projector 120 that projects informational display light 121 onto the window 110 (or some other reflective surface between the EAP and the window) which is reflected as AR display light 122 towards EAP 140. In addition, or alternatively, a display console 130 (e.g., a dashboard) produces console display light 132 towards EAP 140. For conciseness, 122 and 132 may each be referred to simply display light. In its non-attenuating state, EAP 140 receives and transmits display light 122 and 132 into the third zone as eye-entering AR display light 123a and eyeentering console display light 133a, respectively, which is received by the viewer 101. Forconciseness, 123a and 132a may each be referred to simply as eye-entering display light. Display light 122 and 132 light may independently include just a few colors or include a broad spectrum of colors. Display light 122 and 132 are both shown as non-polarized light having two polarizations Pl and P2 (e.g. both x- and y-axis polarization components), but in some alternative embodiments, one or both may include just the first polarization (Pl). That is, in the present embodiment, display light 122 and 132 should at least include the first polarization component (e.g., Pl, aligned with the y-axis), and may optionally include the second polarization component (e.g., P2, aligned to the x-axis). In some embodiments, when in its transmissive state, the EAP 140 transmits a substantial portion of the incident display light, for example, at least 10 %, or alternatively, at least any of 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90%.

[0049] FIGS. IB and ID show optical system 100 in its attenuating state (EAP 140b) in response to a change in the voltage applied to the EAP 140 (electronically adjusted) relative to FIGS. 1A / 1C. Note that in the example depicted in the figures, the arrow in 140b is aligned in the y-axis and such an arrow within an EAP signifies that Pl polarized light is generally transmitted while P2 polarized light is substantially attenuated. Throughout the present disclosure, activation of the attenuating state may occur in response to the detection (or anticipation) of an increase in light intensity of environment light, e.g., from high-intensity light from sun glare, a bright flash, a laser or the like. The high-intensity component of environment light may be broadband or narrowband, non-polarized or polarized. In FIGS. IB and ID the environment light includes high-intensity broadband light 160b. For example, in addition to light from an ambient scene, high-intensity broadband light 160b may include intense light from sun glare, a bright flash, an explosion, lightning, a xenon lamp or some other high-intensity light source (natural or artificial, flash or continuous). Window polarizer 112 substantially blocks or attenuates the first polarization component Pl (aligned with the y-axis) and substantially passes the second polarization P2 (aligned to the x-axis) as polarized high-intensity broadband light 162b (high-intensity polarized environment light) into the second zone 182. Note that the intensity of polarized high-intensity broadband light 162b is reduced relative to high-intensity light broadband light 160b due to removal of the first polarization component by the window polarizer. Even so, polarized high-intensity broadband light 162b may still have sufficient intensity to be harmful to the viewer.

[0050] Once in its attenuating state, EAP 140b substantially blocks or attenuates the second polarization (P2) of any incident visible light. In some examples, EAP 140b may be characterized as having a wideband absorbance or reflectance profile in the second polarization so that it absorbs or reflects light across most or all of the visible spectrum. As such, less of the polarized high-intensity broadband light 162b incident on EAP 140b is transmitted as eyeentering broadband light (163b) into the third zone 183 to the viewer 101. The transmittance of the eye-entering broadband light 163b may, relative to incident polarized high-intensity broadband light 162b be reduced by at least 20%, alternatively by at least any of 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, 99.5%, 99.9%, 99.95%, or 99.99%. The amount of reduction selected depends in part on the nature of the environment and the high-intensity broadband light 160b. For example, for brief sun glare, 20% may be sufficient, but for potentially more severe visual disruption situations (e.g., from an intense flash, explosion, or a laser), much larger reductions may be selected, for example, at least 80% or more. In some cases, e.g., where high intensity broadband light 160b is produced by an intense flash, explosion, a laser, or the like, the transmittance of the eye-entering broadband light 163b may be reduced by at least 80% or alternatively, at least any 90%, 95%, 99%, 99.5%, 99.9%, 99.95%, or 99.99% relative to the high intensity broadband light 160b incident on the window.

[0051] When in the attenuating state, the transmittance of the eye-entering broadband light 163b relative to incident polarized high-intensity broadband light 162b may optionally be referred to herein as the “second environment light transmittance”. In some cases, relative to the first environment light transmittance (when the EAP is in its non-attenuating state), the second environment light transmittance may be reduced by at least 20%, alternatively by at least any of 30%, 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, 99.5%, 99.9%, 99.95%, or 99.99%. As previously mentioned, the amount of reduction selected depends in part on the nature of high- intensity broadband light 160b. For example, for brief sun glare, 20% may be sufficient, but for potentially more severe visual disruption situations (e.g., from an intense flash, explosion, or a laser), much larger reductions may be selected, for example, at least 80% or more.

[0052] In some cases, the intensity of the eye-entering broadband light 163b may, relative to incident polarized high-intensity broadband light 162b (or alternatively relative to high-intensity broadband light 160b) be reduced by at least 0.5 OD, alternatively by at least any of 1 OD, 2OD, 3 OD, or 4 OD, or more. As mentioned, the amount of reduction selected depends in part on the light in environment 181.

[0053] In some embodiments, the intensity (W / cm2) of the eye-entering light 163b is such that it is eye-safe - e.g., within the limits set forth in ANSI (or some other relevant standard for eye safety) for being non-harmful to the eye.

[0054] Although not illustrated, the EAP may optionally include 2 or more individually controllable segments (a “segmented EAP”) that receive and act on polarized environment light in spatially separate areas. For example, an environment may include an area of high-intensity light and other areas of normal (not high-intensity) light. If the high-intensity portion of polarized broadband radiation is only incident on half of the EAP, then only that half of the EAP needs to be adjusted to its attenuating state. Instead of 2 segments, the EAP may have 3, 4, 5, 6, 7, 8, 9, 10, or more. There is no particular limit on the number of segments that the EAP may have, but in some cases, it may be useful not to exceed 100 segments ,or alternatively not to exceed 20 segments, so that the electrical control and manufacturing does not become too complex and expensive. For many applications, 20 or fewer segments is typically sufficient.

[0055] In the configuration shown in FIGS. 1C and ID, upon activation, the viewer is protected from the high-intensity light 160b originating in environment 181 and in some cases, is not able to directly view environment 181. An advantage of the present system, however, is that it is designed to allow the viewer to still see the display light (123b, 133b), even when EAP 140b is activated (in its attenuating state). As shown in FIG. ID, EAP 140b blocks the second polarization component of incident display light 122 and 132, but still substantially transmits the first polarization component as eye-entering display light 123b and 133b, respectively. In some embodiments, at least 10% of incident display light is transmitted through the EAP, alternatively, at least any of 20%, 30%, or 40%. In some embodiments, the EAP 140b is characterized by a photopic transmission of at least 10%, alternatively at least any of 20%, 30%, or 40%. The eyeentering display light(s) is more than sufficient for the viewer to see which can provide important information from the display system (e.g., speed, heading, altitude, GPS maps, radar, camera imaging, status lights... etc.) while light from the environment 181 is substantially blocked.

[0056] In some embodiments, the EAP 140 / 140b surface area is smaller than window polarizer 112 . For example, relative to the EAP surface area, the surface area of the window polarizer islarger by a factor of at least 2x, 5x, lOx, 20x, 50x, lOOx, or even more. As such, the system is relatively simple to make and operate because a large area EAP can be difficult and expensive to manufacture. Further, the present work has found that smaller area EAP devices take much less time to switch to an activated state than a large area EAP. Activation time can be critical when protecting from sudden high-intensity light. Thus, not only does the present disclosure provide a unique, cost effective, and manufacturable light protection system, it is also highly effective due to its rapid switching.

[0057] Some additional embodiments are discussed below, and unless otherwise noted, may have similar advantages or properties as described with respect to FIGS. 1 A- ID. Note that, for simplicity, only AR display light is explicitly illustrated in these additional embodiments, but the optical systems may optionally include (in addition or instead) informational display light from a display console or the like.

[0058] FIGS. 2A and 2B are schematic cross-sectional views of a non-limiting example of an optical system in its non- attenuating state (FIG. 2A) and attenuating state (FIG. 2B). For additional perspective, arbitrary XYZ axes are illustrated along with first (Pl) and second (P2) polarization components. For clarity, not all of the part numbers are shown in FIG. 2B, but the features are the same as in FIG. 2A unless otherwise noted. Optical system 200 includes a window 210 disposed between a viewer 201 and an environment 281 (or first zone) to be viewed. In some embodiments, part 201 may in particular represent a viewer’s eyes.

[0059] Window 210 may include a substrate or windowpane 211 and a window polarizer 212 which may be a static polarizer, or in some cases, a photochromic I photo-dichroic polarizer that activates upon exposure to UV light, or in some cases, an active polarizer. In the present embodiment, window polarizer 212 absorbs or reflects light polarized along the y-axis (Pl) and transmits light polarized along the x-axis (P2). Note that any reference to “x” and “y” polarizations are arbitrary and simply serve to illustrate the general operation of the optical system.

[0060] Environment 281 (first zone) may include various types of environment light within the visible spectrum as previously explained with respect to FIGS. 1A - ID. Environment light that is safe for viewing may include broadband light 260, e.g., non-threat light from an ambient scene. Broadband light 260 is generally not highly polarized and may include both Pl and P2 polarization components (although in some cases, one component may be stronger than theother). The broadband light 260 may, for example, include visible light. Broadband light 260 is received by window polarizer 212 which attenuates a first polarization (Pl - in this case, aligned to the y-axis) and transmits a second polarization (P2 - in this case, aligned to the x-axis) to produced polarized broadband light 262 (polarized environment light) that is transmitted into an intermediate region (second zone) 282. Since the y-axis polarization component has been eliminated, the intensity of broadband light 262 is lower than broadband light 260 (in some cases by ~ 50%), but the environment is generally still readily viewable.

[0061] An electronically adjustable polarizer (EAP) 240 is disposed between viewer 201 and window 210 which is configured to receive the polarized broadband light 262. In the present embodiment, EAP 240 includes an electronic polarization rotator 242 and a static polarizer 244, which may be reflective or absorptive. Static polarizer 244 generally transmits light having a first polarization, Pl - (in this case, along the y-axis) and blocks light having a second polarization P2 (in this case, aligned to the x-axis). P2 is generally orthogonal to Pl. In FIG. 2A, EAP 240 is in its non-attenuating state so that the electronic polarization rotator 242 receives polarized broadband light 262 (having the second polarization) and rotates its polarization (e.g., by 90 degrees) to produce rotated polarized broadband light 262pl that now aligns with the first polarization axis. Rotated polarized broadband light 262pl is received by the static polarizer 244 and is substantially transmitted into the third zone 283 (near-eye region) as eye-entering broadband light 263 which is received by the viewer 201 (in particular, the viewer’s eyes).

[0062] The second zone may optionally include display light produced from an information display system such as a console, a control panel, an AR display, or the like. The display light is also intended for viewing by the viewer. For example, FIG. 2A includes AR display projector 220 that projects informational display light 221 onto window 210 (or some other reflective surface positioned between the EAP and the window) which is reflected as non-polarized display light 222 towards EAP 240. Display light 221 and 222 may be non-polarized light having both x- and y-axis (P2 and Pl) polarization components. Although EAP 240 in its non-attenuating state may also produce rotated display light 222a, it is of no practical consequence and the first polarization component (after rotation) will pass through the static polarizer 244 into the third zone as eye-entering display light 223.

[0063] FIG. 2B shows optical system 200 in its attenuating state. For example, a voltage applied to the EAP 240 (in particular to the electronic polarization rotator 242b) has beenchanged relative to FIG. 2A, so that it is now in its attenuating state (EAP 240b). Activation of the attenuating state may occur in response to the detection (or anticipation) of an increase in light intensity of the environment light, e.g., from high-intensity light from bright flash or a laser or the like. The high-intensity component of environment light may be broadband or narrowband, non-polarized or polarized. In FIG. 2B, the environment light includes high- intensity broadband light 260b. For example, in addition to light from an ambient scene, high- intensity broadband light 260b may include intense light from sun glare, a bright or super-bright flash, an explosion, lightning, a xenon lamp, or some other high-intensity light source (natural or artificial, flash or continuous) Window polarizer 212 preferentially blocks the first polarization component Pl (aligned with the y-axis) and passes the second polarization P2 (aligned to the x- axis) as polarized high-intensity broadband light 262b (high-intensity polarized environment light) into the second zone 282. Note that the intensity of polarized high-intensity broadband light 262b is reduced relative to broadband 260b due to removal of the first polarization component by the window polarizer. Even so, high-intensity broadband light 262b may still have sufficient intensity to be harmful to the viewer.

[0064] In its attenuating state, the electronic polarization rotator 242b is electronically adjusted so that high-intensity polarized broadband light 262b passes as polarized broadband light 262p2 having its polarization orthogonal to the static polarizer 244. In some cases, this may mean there is no rotation by the electronic polarization rotator 242, or alternatively, it is simply a different amount of rotation relative to its non-activated state of FIG. 2A. Once set to its attenuating state, EAP 240b substantially blocks broadband radiation having the second polarization P2 (e.g., aligned to the x-axis). As such, less of the potentially harmful polarized broadband light 262b incident on EAP 240b is transmitted as eye-entering broadband light 263b into the third zone 283 to the viewer 201. Optional display light 222b (FIG. 2B) may also be rotated differently than 222a (FIG. 2A), but it is of no practical consequence and the first polarization component (after rotation) is again transmitted through the static polarizer 244 as eye-entering display light 223b. Note that when display light 222 is non-polarized having about equal x- and y-(P2 and Pl) polarization component intensities, the intensity of transmitted eye-entering display light 223b (attenuating state) will about the same as the intensity of eye-entering display light 223 (nonattenuating state). Thus, the viewer can still observe display light even while being protected from the high-intensity light 260 originating in environment 281, and in some cases, theperceived intensity of the display light is maintained which may provide a less disruptive experience for the viewer.

[0065] The transmittances and metrics of eye-entering broadband light 263 and 263b may be as previously described with respect to FIGS. 1A - ID. Similarly, the transmittances and metrics of eye-entering display light 223 and 223b may be as previously described with respect to FIGS. 1A - ID.

[0066] In the above embodiments, the static polarizer 244 is shown oriented to pass the first polarization component Pl (aligned to the y-axis). However, the static polarizer can instead be aligned to the x-axis at some angle between the x- and y-axes. In light of the disclosure of FIGS. 2 A and 2B, one of ordinary skill will understand that the operation of the electronic polarization rotator can be modified accordingly to produced non-activated and activated states. Although not illustrated, EAP 240 may be a segmented EAP as previously described.

[0067] In some cases, the optical system can protect a viewer from both high-intensity broadband radiation and high-intensity narrowband radiation, e.g., from lasers or the like. FIGS 3A - 3C are simplified cross-sectional schematics to illustrate some non-limiting examples of such optical systems. In these embodiments, the system may be as generally described with respect to FIGS. 1A - ID, but for clarity, the AR display projector, window (windowpane and window polarizer), and viewer are not illustrated in order to focus on the operation of the EAP.

[0068] Referring to FIG. 3A, EAP 340 includes a stack of three electronic polarizers (e.g., three e-PODs) that are individually addressable, 340R, 340G, and 340B. As shown here, each e- POD is shown in its non-attenuating state and will substantially transmit incident light of both polarizations. For example, optional non-polarized display light 322 is transmitted as eyeentering display light 323, and polarized broadband light 362 (polarized environment light, not high intensity) is transmitted as eye-entering broadband light 363.

[0069] In FIG. 3B, each e-POD is in its attenuating state. e-POD 340R substantially blocks red light having the second polarization, but will transmit red light of the first polarization along with other non-red (e.g. blue and green) light of either polarization. Similarly, 340G substantially blocks green light having the second polarization, but will transmit green light of the first polarization along with non-green (e.g. blue and red) light of either polarization. Further, 340B substantially blocks blue light having the second polarization, but will transmit blue light of the first polarization along with non-blue (e.g. green and red) light of either polarization.Together, 340R, 340G, and 340B may substantially block high intensity polarized broadband light 362b (high-intensity polarized environment light) so that only a small amount is transmitted as eye-entering broadband light 363b. While the second polarization component of optional display light 322 is absorbed, the first polarization component of display light 322 is transmitted as eye-entering display light 323b. As such, this configuration can protect a viewer from high- intensity broadband light while still permitting display light to be seen. However, since this configuration of the EAP employs various layers with selective absorption bands, it is more flexible.

[0070] For example, referring to FIG. 3C, EAP 340 is activated in a different configuration where only e-POD 340G is activated to block green light having the second polarization. For example, in addition to optional non-polarized display light 322 and polarized broadband light 362 (polarized environment light, not high intensity), high intensity polarized narrowband radiation such as a green laser 372 (high-intensity polarized environment light) is also incident on EAP 340 Note that only the second polarization component of the green laser is transmitted by the window polarizer (not shown). By activating 340G, most of the green laser light is substantially blocked and only a small (safe) amount may be transmitted as eye-entering narrowband radiation 373. The green P2 component of polarized broadband light 362 is also substantially blocked, but red and blue components are transmitted as eye-entering broadband light 363c. With respect to display light 322, the P2 component of green light is substantially blocked, but the Pl component of green is transmitted along with much of the red and blue light of both polarizations (Pl and P2) to produce eye-entering display light 323c. In this way, a viewer can be protected from dangerous laser light, but still see the display light and much of the broadband light that originated in the first zone.

[0071] FIGS 4A - 4D illustrate another configuration, focusing on the EAP. Here, the EAP 440 includes a stack of two e-POD devices, 440wb and 440G. e-POD 440wb may be designed in its attenuating state to substantially block the second polarization component P2 of broadband light, e.g., across much or all of the visible spectrum. e-POD 440wb may be characterized as having a wide band absorbance (wide-band blocking). e-POD 440G on the other hand is designed in its attenuating state to substantially block the second polarization component of narrowband radiation, e.g., high-intensity narrowband radiation, such as from a green laser. In its completely non-attenuated state (FIG. 4A), both e-PODs substantially transmit visible light ofeither polarization across. If a laser is detected, 440G may be activated to its attenuating state to substantially block it (FIG. 4B), but the viewer will still observe (optional) display light and broadband light originating from the first zone as explained elsewhere with respect to other embodiments. If high-intensity broadband light is detected and converted to polarized high- intensity broadband light, 440wb may be activated to block it (FIG. 4C), but the viewer will still be able to see display light as explained elsewhere with respect to other embodiments. If both high-intensity broadband light and narrowband radiation are detected, both e-PODs may be activated (FIG. 4D). Although just activating 440wb may in some cases be enough to block laser light in addition to the high-intensity broadband light, in this case activating 440G provides additional safety by additionally absorbing the green laser light. A viewer will still be able to see display light as explained elsewhere.

[0072] In some cases, an optical system may be designed primarily to protect against high- intensity narrowband radiation such as lasers. FIGS. 5A and 5B are schematic cross-sectional views of a non-limiting example of an optical system in its non- attenuating state (FIG. 5A) and attenuating state (FIG. 5B). Optical system 500 includes a window 510 disposed between a viewer 501 and an environment 581 (or first zone) to be viewed.

[0073] Window 510 may include a substrate or windowpane 511 and a at least one narrow band window polarizer 512G which may be a static polarizer or an active polarizer. Narrow band polarizers may also be referred to as wavelength- selective polarizers. Although the window polarizer may in some other cases have a wide band absorbance / reflectance profile, in the present embodiment, window polarizer 512G may be characterized as having a narrow band window polarizer and may preferentially attenuate (reflect or absorb) the first polarization component of only a portion of the visible spectrum, e.g., the green, and preferentially transmits the second polarization component. The absorption / reflectance spectrum and peak absorbance / reflectance may, for example, be matched to a peak intensity wavelength common high-intensity narrowband radiation (e.g., lasers) that a viewer may encounter. In one nonlimiting example, it may be particularly suited to block the first polarization component of green light having a peak intensity wavelength centered near 532 nm, a typical laser radiation peak wavelength. In the present embodiment, window polarizer 512G will substantially transmit blue and red light of both polarizations and the second polarization of green light.

[0074] Environment 581 (first zone) may include various types of environment light within the visible spectrum as previously explained with respect to FIGS. 1A - ID. Environment light that is safe for viewing may include broadband light 560, e.g., non-threat light from an ambient scene. Broadband light 560 is generally not highly polarized and may include both Pl and P2 polarization components (although in some cases, one component may be stronger than the other). The broadband light 560 may, for example, include visible light. Broadband light 560 is received by window polarizer 512G which attenuates a first polarization Pl (in this case, along the y-axis) of the green portion of the broadband light and transmits a second polarization P2 (in this case, along the x-axis) of the green light, and also transmits both polarizations of red and blue to produce partially polarized broadband light 562 (polarized environment light) that is transmitted into an intermediate region (second zone) 582.

[0075] An electronically adjustable polarizer (EAP) 540G is disposed between viewer 501 and window 510 which is configured to receive the partially polarized broadband light 562. There are numerous options for the construction and operation of the EAP, which may be reflective or absorptive. In FIG. 5A, EAP 540G is a narrow band absorptive electronic polarizer (also referred to as a wavelength-selective electronic polarizer) in its non- attenuating state. In this state, EAP 540G generally does not preferentially absorb either polarization, but instead, can substantially transmit light of both polarizations across the visible spectrum. As such, partially polarized broadband light 562 is transmitted into a near-eye region (third zone) 583 between the viewer and the EAP as eye-entering broadband light 563 which is received by the viewer 501 (in particular, the viewer’s eyes).

[0076] The second zone may optionally include display light produced from an information display system such as a console, a control panel, an AR display, or the like. The display light is also intended for viewing by the viewer. For example, FIG. 5A includes AR display projector 520 that projects informational display light 521 onto window 510 (or some other reflective surface between the window and the EAP) which is reflected as display light 522 towards EAP 540G. In its non- attenuating state, EAP 540 receives and transmits display light 522 into the third zone as eye-entering display light 523 which is received by the viewer 501. The display light may include just a few colors or a broad spectrum of colors. Display light 522 is shown as non-polarized light having both x- and y-axis polarization components (P2 and Pl), but in some alternative embodiments, it may include just Pl (aligned to the y-axis).

[0077] FTG. 5B shows optical system 500 in its attenuating state. For clarity, not all of the part numbers arc shown in FIG. 5B, but the features arc the same as in FIG. 5A unless otherwise noted. For example, a voltage applied to the EAP 540G has been changed relative to FIG. 5A (electronically adjusted), so that it is now in its attenuating state (EAP 540Gb). This change in voltage may occur in response to the detection (or anticipation) of high-intensity narrowband radiation such as a laser 570 (e.g., a green laser). It is common for lasers to be highly polarized. If by chance, laser light 570 was incident with its polarization aligned to the y-axis, it would be substantially blocked. However, as shown, if it has a polarization oriented somewhere between the x- and y-axes, or an orientation in the x-axis (P2) then the laser light 570 will be transmitted as polarized laser light 572 (high-intensity polarized environment light) having the second polarization. It may be reduced in intensity relative to laser light 570, but may still be harmful.

[0078] Once activated to its attenuating state, EAP 540Gb substantially blocks narrowband radiation (e.g., green laser light) having the second polarization P2. EAP 540Gb may be characterized as having a narrow band absorbance profile tuned especially for the incident narrowband radiation. As such, very little of the polarized laser light 572 incident on EAP 540Gb passes through as eye-entering laser light (573) into the third zone 583 and to the viewer 501. The intensity of eye-entering laser light 573 may, relative to incident laser light 570 (or alternatively relative to laser light 572) be reduced by at least 20%, or alternatively by at least any of 40%, 50%, 60%, 70%, 80%, 90%, 95%, 99%, 99.5%, 99.9%, 99.95%, or 99.99%. The intensity of the eye-entering laser light 573 may, relative to incident laser light 570 (or alternatively relative to laser light 572) be reduced by at least 0.5 OD, alternatively by at least any of 1 OD, 2 OD, 3 OD, or 4 OD

[0079] Thus, upon activation, the viewer is protected from the high-intensity light originating in environment 581. Further, since only the second polarization component of green light is blocked when EAP 540Gb is activated, all polarizations of blue and red light in addition to the first polarization of green light present in display light 522 and in partially polarized broadband light 562 are transmitted as eye-entering display light 523b and as eye-entering broadband light 563b. Thus, even while being protected from laser light, a viewer can still see the environment light and display light with only a minor but acceptable loss or change of color fidelity.

[0080] In some cases, when electronically adjusted to its attenuating state, the EAP blocks at least 50% of the partially polarized environment light at the peak wavelength (alternatively atleast any of 60%, 70%, 80%, 90%, 99%, 99.9%, or 99.99%) and transmits at least 20% of the partially polarized environment light at one more wavelengths at least 50 nm away from the peak wavelength (alternatively at least any of 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, or 90%). In a non-limiting example, the EAP may block at least 80% of the green light and transmit at least 25% of blue light or red light.

[0081] Although not illustrated, the window 510 may further include a wide band window polarizer, e.g., if both laser and high-intensity bright broadband light are expected in the environment. Also not illustrated, the window may include a second narrow band window polarizer that preferentially attenuates a first polarization component of light at a second wavelength, e.g., at least 10 nm away from the peak absorption / reflection of narrow band window polarizer 512G. For example, the second narrow band window polarizer may be designed to block red or blue laser light, but otherwise operate in a manner similar to that described with respect to narrow band window polarizer 512G. Although not illustrated, EAP 540G may be a segmented EAP as previously described.

[0082] In some embodiments, e.g., as discussed in FIGS. 2A and 2B, an electronic polarization rotator may be present to electronically change the angle of polarization. The operation depends on the layers used and the location of the incident and transmitted light on the Poincare Sphere. FIG. 6A is a schematic diagram of an electronic polarization rotator 620A, according to some embodiments. In this configuration, a stack of 2 static quarter waveplates 624 and 625 whose axis are at 90 degrees to each other sandwiches an electronically controllable waveplate 626 with the axis at 45 degrees to the principal axis of the two quarter waveplates. The electronically controllable waveplate may include electronically controllable polarization-rotating liquid crystal cell disposed. Such devices are known in the art and sometimes referred to as an electronically controlled birefringence (ECB) liquid crystal device. Application of the voltage to the electronically controllable waveplate will act on the arbitrary linear polarization of incident light to produce a desired (rotated) linear transmitted polarized radiation that is received by the static polarizer 244 (FIGS. 2 A and 2B).

[0083] If incident polarized radiation is circular or elliptical, an alternative construction can be made as shown in FIG. 6B as electronic polarization rotator 620B. In this embodiment, the first static quarter waveplate can be replaced with another electronically controllable waveplate 627. In this case, if the incident light has circular or elliptical polarization, the waveplate can be tunedto impart any phase (including, but not limited to, 0 degrees) to the incident light to produce the desired rotated polarized radiation.

[0084] For the optical system to operate effectively, the window polarizer and the EAP should act on (absorb / reflect) at least partially overlapping regions of electromagnetic radiation in the visible spectrum. For example, if the window polarizer is a narrow band type acting only on green light, the EAP should preferably act on at green light (and optionally also on red and / or blue). If the window polarizer is a broad band type acting across much of the visible spectrum, e.g., red, green, and blue, then the EAP should act on at least one of the red, green, and blue regions, but optionally on two or all three of these regions. That is, in some cases, the window polarizer and the EAP may each absorb or reflect different but overlapping regions of electromagnetic radiation and produce a useful optical system. Some of the most effective embodiments may occur when they each absorb or reflect substantially the same region of electromagnetic radiation.

[0085] The degree of similarity or difference between the window polarizer and EAP spectral envelopes can be quantified in many ways. In one non-limiting way, as shown in FIG. 7, the Pl absorbance or reflectance spectrum of a window polarizer 712 may be characterized by a fullwidth half-max wavelength range 717 (“WP bandwidth range” 717). Similarly, the P2 absorbance or reflectance spectrum of an EAP 740 in its attenuating state may be characterized by a full- width half-max wavelength range 747 (“EAP bandwidth range” 747). These spectra are non-limiting examples for general explanatory purposes and the absorbance / reflectance intensities are in arbitrary units to compare some non-limiting spectral shapes. The absolute absorbance / reflectance intensity of the window polarizer may in some cases be very different from the EAP. The WP bandwidth range 717 in the present embodiment extends from about 440 nm to 720 nm (280 nm FWHM bandwidth). The EAP bandwidth in the present embodiment extends from about 460 nm to 730 nm (270 nm FWHM bandwidth). The overlap range is 460 nm to 720 nm (260 nm FWHM overlap). In this example, about 96% of the EAP bandwidth range overlaps with the WP bandwidth range. Further, about 93% of the WP bandwidth range overlaps the EAP bandwidth range.

[0086] FIG. 8 is similar to FIG. 7, but there is less overlap. In FIG. 8, the WP bandwidth range 717 extends from about 420 nm to 610 nm (190 nm FWHM bandwidth) and the EAP bandwidth range extends from about 510 nm to 730 nm (220 nm FWHM bandwidth). The overlap range is510 nm to 610 nm (100 nm overlap). In this example, about 45% of the EAP bandwidth range overlaps with the WP bandwidth range. Further, about 53% of the WP bandwidth range overlaps with the EAP bandwidth range.

[0087] Although the non-limiting examples of FIGS. 7 and 8 use wide band polarizers, the same analysis can be applied to narrow band polarizers. In some cases, the window polarizer and the EAP may be said to absorb or reflect substantially the same region of electromagnetic radiation when at least 80% of the EAP bandwidth range overlaps the WP bandwidth range, and when at least 80% of the WP bandwidth range also overlaps with the EAP bandwidth range. In some cases, the window polarizer and the EAP may be said to absorb or reflect different but overlapping regions when the above conditions for “substantially the same region” are not satisfied, but there is at least 5% overlap between the EAP bandwidth range and the WP bandwidth range or there is at least 5% overlap range between the WP bandwidth range and the EAP bandwidth range.

[0088] In another analysis, the overlap range may be compared to a combined FWHM range encompassed by the polarizers together. Referring again to FIG. 7, the FWHM overlap range was 260 nm. The combined FWHM range encompassed by the polarizers together extends from 440 nm to 720 nm (combined FWHM range of 280 nm). In some cases, the window polarizer and EAP may be said to absorb or reflect substantially the same region of electromagnetic radiation when the ratio of the FWHM overlap range to the FWHM combined range is at least 0.8. In some cases, the window polarizer and the EAP may be said to absorb or reflect different but overlapping regions when the ratio of the FWHM overlap range to the FWHM combined range is less than 0.8 but at least 0.05.

[0089] While various embodiments have been discussed with respect to the visible spectrum for polarized narrowband radiation and non-polarized broadband radiation, the methods and devices can be applied to narrowband wavelengths and broadband spectra in the infrared or ultraviolet.

[0090] Still further embodiments herein include the following non-limiting enumerated embodiments.

[0091] Enumerated embodiment 1. A light protection optical system for attenuating environment light, the system including: a window disposed between a viewer and an environment including environment light within the visible spectrum, wherein the windowincludes a window polarizer that preferentially attenuates a first polarization component (Pl ) of environment light and preferentially transmits a second polarization component (P2) of environment light to produce a polarized environment light; and an electronically adjustable polarizer (EAP) disposed between the viewer and the window, wherein the EAP is configured to receive the polarized environment light, wherein, when electronically adjusted to produce a nonattenuating state, the EAP transmits the polarized environment light as eye-entering light having a first environment light transmittance, and wherein, when electronically adjusted to produce an attenuating state, the EAP attenuates the transmission of the second polarization component (P2) of the polarized environment light to produce eye-entering light having second environment light transmittance that is at least 20% lower than the first environment light transmittance.

[0092] Enumerated embodiment 2. The optical system of enumerated embodiment 1, wherein the EAP is further configured to receive at least one display light from one or more information display systems, wherein the display light includes at least a first polarization component (Pl) and optionally, a second polarization component (P2), wherein, when in the attenuating state, the EAP preferentially attenuates the optional second polarization components (P2) of display light while preferentially transmitting the first polarization component (Pl) of the display light such that at least 10% of display light incident on the EAP is transmitted as eye-entering display light.

[0093] Enumerated embodiment 3. The optical system of enumerated embodiment 2, wherein the display light includes the second polarization component (P2).

[0094] Enumerated embodiment 4. The optical system of enumerated embodiment 2 or 3, wherein the information display system includes an augmented reality display, a console, or a control panel.

[0095] Enumerated embodiment 5. The optical system according to any of enumerated embodiments 2 - 4, wherein the second environment light transmittance is at least 50% lower than the first environment light transmittance, optionally at least 80% lower.

[0096] Enumerated embodiment 6. The optical system according to any of enumerated embodiments 1 - 5, wherein the attenuating state is produced in response to the presence or threat of high-intensity environment light.

[0097] Enumerated embodiment 7. The optical system of enumerated embodiment 6, wherein the high-intensity environment light includes laser light, light from a bright explosion, or both.

[0098] Enumerated embodiment 8. The optical system according to any of enumerated embodiments 1 - 7, wherein the window polarizer is a static polarizer.

[0099] Enumerated embodiment 9. The optical system according to any of enumerated embodiments 1 - 7, wherein the window polarizer is an active polarizer, or a photochromic or photochromic-dichroic polarizer that activates upon exposure to UV light.

[0100] Enumerated embodiment 10. The optical system according to any of enumerated embodiments 1 - 9, wherein the window polarizer is an absorptive polarizer.

[0101] Enumerated embodiment 11. The optical system according to any of enumerated embodiments 1 - 9, wherein the window polarizer is a reflective polarizer.

[0102] Enumerated embodiment 12. The optical system according to any of enumerated embodiments 1 - 11, wherein the window polarizer is a wide band polarizer.

[0103] Enumerated embodiment 13. The optical system of enumerated embodiment 12, wherein the window polarizer preferentially absorbs or reflects at least 10% of the first polarization component (Pl) of the environment light across a wavelength range of 400 nm to 700 nm.

[0104] Enumerated embodiment 14. The optical system according to any of enumerated embodiments 1 - 13, wherein the window polarizer is a narrow band polarizer.

[0105] Enumerated embodiment 15. The optical system according to any of enumerated embodiments 1 - 14, wherein the window polarizer has peak contrast ratio of at least 5:1.

[0106] Enumerated embodiment 16. The optical system according to any of enumerated embodiments 1 - 15, wherein the window polarizer has an integral contrast ratio of at least 5:1

[0107] Enumerated embodiment 17. The optical system according to any of enumerated embodiments 1 - 16, wherein the EAP includes an active absorptive polarizer, optionally a graduated active absorptive polarizer.

[0108] Enumerated embodiment 18. The optical system of enumerated embodiment 17, wherein the active absorptive polarizer has a wide band absorbance.

[0109] Enumerated embodiment 19. The optical system of enumerated embodiment 17, wherein the active absorptive polarizer has a narrow band absorbance.

[0110] Enumerated embodiment 20. The optical system according to any of enumerated embodiments 1 - 19, wherein the EAP includes a stack of two or more active absorptive polarizers.

[0111] Enumerated embodiment 21 . The optical system of enumerated embodiment 20, wherein at least two of the active absorptive polarizers of the stack have different spectral absorption profiles.

[0112] Enumerated embodiment 22. The optical system of enumerated embodiment 20 or 21, wherein one of the active absorptive polarizers of the stack has a peak absorption wavelength that is at least 10 nm away from a peak absorption wavelength of another active absorptive polarizer in the stack.

[0113] Enumerated embodiment 23. The optical system of enumerated embodiment 20, wherein at least two of the active absorptive polarizers of the stack have substantially the same spectral absorption profile.

[0114] Enumerated embodiment 24. The optical system of enumerated embodiment 20 or 23, wherein one of the active absorptive polarizers of the stack has a peak absorption wavelength that is within 10 nm of a peak absorption wavelength of another active absorptive polarizer in the stack.

[0115] Enumerated embodiment 25. The optical system according to any of enumerated embodiments 1 - 24, wherein the EAP includes an electronic polarization rotator.

[0116] Enumerated embodiment 26. The optical system according to any of enumerated embodiments 1 - 25, wherein the window polarizer and the EAP each absorb or reflect substantially the same region of electromagnetic radiation.

[0117] Enumerated embodiment 27. The optical system according to any of enumerated embodiments 1 - 25, wherein i) the absorbance or reflectance of the window polarizer is characterized by a full-width half-max wavelength range (“WP bandwidth range”), ii) the absorbance or reflectance of the EAP is characterized by a full- width half-max wavelength range (“EAP bandwidth range”), iii) at least 80% of the EAP bandwidth range overlaps with the WP bandwidth range, and iv) at least 80% of the WP bandwidth range overlaps with the EAP bandwidth range.

[0118] Enumerated embodiment 28. The optical system according to any of enumerated embodiments 1 - 25, wherein the window polarizer and the EAP absorb or reflect different but overlapping regions of electromagnetic radiation.

[0119] Enumerated embodiment 29. The optical system according to any of enumerated embodiments 1 - 25 or 28, wherein i) the absorbance or reflectance of the window polarizer ischaracterized by a full-width half-max wavelength range (“WP bandwidth range”), ii) the absorbance or reflectance of the EAP is characterized by a full- width half-max wavelength range (“EAP bandwidth range”), iii) there is less than 80% overlap for at least one of the EAP bandwidth range relative to the WP bandwidth range or the WP bandwidth range relative to the EAP bandwidth range, and iv) there is at least 5% overlap for at least one of the EAP bandwidth range relative to the WP bandwidth range or the WP bandwidth relative to the EAP bandwidth range.

[0120] Enumerated embodiment 30. The optical system according to any of enumerated embodiments 1 - 29, wherein the window polarizer and the EAP each absorb or reflect a radiation band chosen from: broadband, narrowband, or ultra narrowband radiation.

[0121] Enumerated embodiment 31. The optical system according to any of enumerated embodiments 1 - 30, wherein the window forms part of a vehicle windshield, aircraft canopy, protective shield, a helmet, or a building structure.

[0122] Enumerated embodiment 32. The optical system according to any of enumerated embodiments 1 - 31, wherein the EAP is incorporated into eyewear, goggles, or a visor worn by the viewer.

[0123] Enumerated embodiment 33. The optical system according to any of enumerated embodiments 1 - 32, wherein the EAP includes at least two individually controllable segments that receive the polarized environment light in spatially separate areas.

[0124] Enumerated embodiment 34. A method of using the optical system according to any of enumerated embodiments 1 - 33, the method including switching the EAP from the nonattenuating state to the attenuating state.

[0125] Enumerated embodiment 35. A light protection optical system for attenuating environment light, the system including: a window disposed between a viewer and an environment including environment light within the visible spectrum including broadband radiation and narrowband radiation, the narrowband radiation having a peak wavelength, wherein the window includes at least one narrow band window polarizer that preferentially attenuates a first polarization component (Pl) of environment light at the peak wavelength and preferentially transmits a second polarization component (P2) of environment light at the peak wavelength to produce a partially polarized environment light; and an electronically adjustable polarizer (EAP) disposed between the viewer and the window, wherein the EAP is configured toreceive the partially polarized environment light, wherein, when electronically adjusted to produce an attenuating state, the EAP blocks at least 50% of the partially polarized environment light at the peak wavelength and transmits at least 20% of the partially polarized environment light at one or more wavelengths at least 50 nm away from the peak wavelength.

[0126] Enumerated embodiment 36. The optical system of enumerated embodiment 35, wherein the EAP blocks at least 80% of the partially polarized environment light at the peak wavelength and transmits at least 25% of the partially polarized environment light at one or more wavelengths at least 50 nm away from the peak wavelength.

[0127] Enumerated embodiment 37. The optical system of enumerated embodiment 35 or 36, wherein the EAP blocks at least 90%, or optionally at least 99%, of the partially polarized environment light at the peak wavelength.

[0128] Enumerated embodiment 38. The optical system according to any of enumerated embodiments 35 - 37, wherein the EAP transmits at least 35%, or optionally at least 55%, of the partially polarized environment light at one or more wavelengths at least 50 nm away from the peak wavelength.

[0129] Enumerated embodiment 39. The optical system according to any of enumerated embodiments 35 - 38, wherein the EAP is further configured to receive at least one display light from one or more information display systems, wherein the display light includes at least a first polarization component (Pl) and optionally, a second polarization component (P2), wherein, when in the attenuating state, the EAP preferentially attenuates the optional second polarization components (P2) of display light while preferentially transmitting the first polarization component (Pl) of the display light such that at least 10% of display light incident on the EAP is transmitted as eye-entering display light.

[0130] Enumerated embodiment 40. The optical system of enumerated embodiment 39, wherein the display light includes the second polarization component (P2).

[0131] Enumerated embodiment 41. The optical system of enumerated embodiment 39 or 40, wherein the information display system includes an augmented reality display.

[0132] Enumerated embodiment 42. The optical system according to any of enumerated embodiments 39 - 41, wherein the information display system includes a console or a control panel.

[0133] Enumerated embodiment 43. The optical system according to any of enumerated embodiments 35 - 42, wherein the attenuating state is produced in response to the presence of the narrowband radiation.

[0134] Enumerated embodiment 44. The optical system according to any of enumerated embodiments 35 - 43, wherein the narrowband radiation includes laser light.

[0135] Enumerated embodiment 45. The optical system according to any of enumerated embodiments 35 - 44, wherein the at least one narrow band window polarizer is a static polarizer, an absorptive polarizer, or a reflective polarizer.

[0136] Enumerated embodiment 46. The optical system according to any of enumerated embodiments 35 - 45, wherein the window further includes a wide band window polarizer.

[0137] Enumerated embodiment 47. The optical system according to any of enumerated embodiments 35 - 46, wherein the peak wavelength corresponds to a first peak wavelength, and the window further includes a second narrow band window polarizer that preferentially attenuates a first polarization component (Pl) of environment light at a second peak wavelength and preferentially transmits a second polarization component (P2) of environment light at the second peak wavelength, wherein the second peak wavelength is at least 10 nm away from the second peak wavelength.

[0138] Enumerated embodiment 48. The optical system of enumerated embodiment 47, wherein the environment light further includes second narrowband radiation having a peak wavelength corresponding to the second peak wavelength.

[0139] Enumerated embodiment 49. The optical system of enumerated embodiment 47 or 48, wherein, when electronically adjusted to produce the attenuating state, the EAP blocks at least 50%, or optionally at least 80%, of the partially polarized environment light at the second peak wavelength and transmits at least 20%, or optionally at least 30%, of the partially polarized environment light at one or more wavelengths at least 50 nm away from the second peak wavelength.

[0140] Enumerated embodiment 50. The optical system according to any of enumerated embodiments 35 - 49, wherein the at least one narrow band window polarizer has peak contrast ratio or an integral contrast ratio of at least 5 : E

[0141] Enumerated embodiment 51 . The optical system according to any of enumerated embodiments 35 - 50, wherein the EAP includes an active absorptive polarizer, optionally a graduated active absorptive polarizer.

[0142] Enumerated embodiment 52. The optical system of enumerated embodiment 51, wherein the active absorptive polarizer has a wide band absorbance.

[0143] Enumerated embodiment 53. The optical system of enumerated embodiment 51, wherein the active absorptive polarizer has a narrow band absorbance.

[0144] Enumerated embodiment 54. The optical system according to any of enumerated embodiments 35 - 53, wherein the EAP includes a stack of two or more active absorptive polarizers.

[0145] Enumerated embodiment 55. The optical system of enumerated embodiment 54, wherein at least two of the active absorptive polarizers of the stack have different spectral absorption profiles.

[0146] Enumerated embodiment 56. The optical system of enumerated embodiment 54 or 56, wherein one of the active absorptive polarizers of the stack has a peak absorption wavelength that is at least 10 nm away from a peak absorption wavelength of another active absorptive polarizer in the stack.

[0147] Enumerated embodiment 57. The optical system of enumerated embodiment 54, wherein at least two of the active absorptive polarizers of the stack have substantially the same spectral absorption profile.

[0148] Enumerated embodiment 58. The optical system of enumerated embodiment 54 or 57, wherein one of the active absorptive polarizers of the stack has a peak absorption wavelength that is within 10 nm of a peak absorption wavelength of another active absorptive polarizer in the stack.

[0149] Enumerated embodiment 59. The optical system according to any of enumerated embodiments 35 - 58, wherein the EAP includes an electronic polarization rotator.

[0150] Enumerated embodiment 60. The optical system according to any of enumerated embodiments 35 - 59, wherein the at least one narrow band window polarizer and the EAP each absorb or reflect substantially the same region of electromagnetic radiation.

[0151] Enumerated embodiment 61. The optical system according to any of enumerated embodiments 35 - 60, wherein the EAP in its attenuating state is characterized by a maximumabsorbance or reflectance wavelength that is within 10 nm of the peak wavelength, optionally within 5 nm of the peak wavelength.

[0152] Enumerated embodiment 62. The optical system according to any of enumerated embodiments 35 - 60, wherein the at least one narrow band window polarizer and the EAP each absorb or reflect different but overlapping regions of electromagnetic radiation.

[0153] Enumerated embodiment 63. The optical system according to any of enumerated embodiments 35 - 59 or 62, wherein the EAP in its attenuating state is characterized by a maximum absorbance or reflectance wavelength that is at least 10 nm away from the peak wavelength, and wherein an amount of attenuation by the EAP at the peak wavelength is at least 5%, optionally at least 10%, of an amount of attenuation by the EAP at its maximum absorbance or reflectance wavelength.

[0154] Enumerated embodiment 64. The optical system according to any of enumerated embodiments 35 - 63, wherein the window forms part of a vehicle windshield, aircraft canopy, protective shield, a helmet, or a building structure.

[0155] Enumerated embodiment 65. The optical system according to any of enumerated embodiments 35 - 64, wherein the EAP is incorporated into eyewear, goggles, or a visor worn by the viewer.

[0156] Enumerated embodiment 66. The optical system according to any of enumerated embodiments 35 - 65, wherein the EAP includes at least two individually controllable segments that receive the polarized environment light in spatially separate areas.

[0157] Enumerated embodiment 67. A method of using the optical system according to any of enumerated embodiments 35 - 66, the method including switching the EAP from a nonattenuating state to the attenuating state.

[0158] The specific details of particular embodiments may be combined in any suitable manner without departing from the spirit and scope of embodiments of the invention. However, other embodiments of the invention may be directed to specific embodiments relating to each individual aspect, or specific combinations of these individual aspects.

[0159] The above description of example embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations arc possible in light of the teaching above.

[0160] In the preceding description, for the purposes of explanation, numerous details have been set forth in order to provide an understanding of various embodiments of the present technology. It will be apparent to one skilled in the art, however, that certain embodiments may be practiced without some of these details, or with additional details.

[0161] Having described several embodiments, it will be recognized by those of skill in the art that various modifications, alternative constructions, and equivalents may be used without departing from the spirit of the invention. Additionally, a number of well-known processes and elements have not been described in order to avoid unnecessarily obscuring the present invention. Additionally, details of any specific embodiment may not always be present in variations of that embodiment or may be added to other embodiments.

[0162] Unless otherwise noted, a phrase that recites a range of values is inclusive of the end values, for example, “between X and Y,” “range of X to Y,” “from X to Y,” “from X - Y”, each includes X and Y. Similarly, unless otherwise noted, the phrase “up to Y” includes Y and the phrase “down to X” includes X. Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither, or both limits are included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included.

[0163] As used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a method” includes a plurality of such methods and reference to “the layer” includes reference to one or more layers and equivalents thereof known to those skilled in the art, and so forth. The invention has now been described in detail for the purposes of clarity and understanding. However, it will be appreciated that certain changes and modifications may be practiced within the scope of the appended claims.

[0164] All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes. None is admitted to be prior art.

[0165] Listing of Reference Numerals in Figures100 - optical system101 - viewer110 - window111 - windowpane112 - window polarizer120 - AR display projector121 - informational display light122 - AR display light123a - eye-entering AR display light123b - eye-entering AR display light130 - display console132 - console display light133a - eye-entering console display light133b - eye-entering console display light140 - electronically adjustable polarizer (EAP) in its non- attenuating state140b - EAP in its attenuating state160 - broadband light160b - high-intensity broadband light162 - polarized broadband light (polarized environment light)162b - high-intensity polarized broadband light163a - eye-entering broadband light163b - eye-entering broadband light181 - environment (first zone)182 - intermediate region (second zone)183 - near-eye region (third zone)200 - optical system201 - viewer210 - window21 1 - windowpane212 - window polarizer220 - AR display projector221 - informational display light222 - display light222a - display light222b - display light223 - eye-entering display light223b - eye-entering display light240 - EAP in its non- attenuating state240b - EAP in its attenuating state242 - electronic polarization rotator242b - electronic polarization rotator244 - static polarizer260 - broadband light260b - high-intensity broadband light262 - polarized broadband light (polarized environment light)262b - polarized high-intensity broadband light262pl -polarized broadband light262p2 -polarized high-intensity broadband light263 - eye-entering broadband light263b - eye-entering broadband light281 - environment (first zone)282 - intermediate region (second zone)283 - near-eye region (third zone)322 - non-polarized display light323 - eye-entering display light323b - eye-entering display light323c - eye-entering display light340 - EAP340R - red-blocking electronic polarizer (e-POD)340G - green-blocking e-POD340B - blue-blocking c-POD362 - polarized broadband light362b - polarized high-intensity broadband light363 - eye-entering broadband light.363b - eye-entering broadband light363c - eye-entering broadband light372 - green laser light373 - eye-entering narrowband radiation (green laser light)440 - EAP440wb - wide-band-blocking e-POD440G - green-blocking e-POD500 - optical system501 - viewer510 - window511 - windowpane512G - narrow band window polarizer520 - AR display projector521 - informational display light522 - display light523 - eye-entering display light523b - eye-entering display light540G - EAP in its non-attenuating state540Gb - EAP in its attenuating state560 - broadband light562 - partially polarized broadband light563 - eye-entering broadband light563b - eye-entering broadband light570 - green laser light572 - polarized laser light573 - eye-entering laser light581 - environment (first zone)582 - intermediate region (second zone)583 - near-eye region (third zone)620A - electronic polarization rotator 620B - electronic polarization rotator624 - static quarter waveplate625 - static quarter waveplate626 - electronically controllable waveplate627 - electronically controllable waveplate 712 - spectrum of window polarizer717 - WP bandwidth range740 - spectrum of EAP in its attenuating state747 - EAP bandwidth range

Claims

CLAIMSWhat is claimed is:

1. A light protection optical system for attenuating environment light, the system comprising: a window disposed between a viewer and an environment comprising environment light within the visible spectrum, wherein the window comprises a window polarizer that preferentially attenuates a first polarization component (Pl) of environment light and preferentially transmits a second polarization component (P2) of environment light to produce a polarized environment light; and an electronically adjustable polarizer (EAP) disposed between the viewer and the window, wherein the EAP is configured to receive the polarized environment light, wherein, when electronically adjusted to produce a non-attenuating state, the EAP transmits the polarized environment light as eye-entering light having a first environment light transmittance, and wherein, when electronically adjusted to produce an attenuating state, the EAP attenuates the transmission of the second polarization component (P2) of the polarized environment light to produce eye-entering light having second environment light transmittance that is at least 20% lower than the first environment light transmittance.

2. The optical system of claim 1, wherein the EAP is further configured to receive at least one display light from one or more information display systems, wherein the display light comprises at least a first polarization component (Pl) and optionally, a second polarization component (P2), wherein, when in the attenuating state, the EAP preferentially attenuates the optional second polarization components (P2) of display light while preferentially transmitting the first polarization component (Pl) of the display light such that at least 10% of display light incident on the EAP is transmitted as eye-entering display light.

3. The optical system of claim 2, wherein the display light comprises the second polarization component (P2).

4. The optical system of claim 2, wherein the one or more information display systems comprise an augmented reality display, a console, a control panel, or any combination thereof.

5. The optical system of claim 1 , wherein the second environment light transmittance is at least 80% lower than the first environment light transmittance.

6. The optical system of claim 1, wherein the window polarizer is a static polarizer.

7. The optical system of claim 1, wherein the window polarizer is an active polarizer, or wherein the window polarizer is a photochromic or photochromic-dichroic polarizer that activates upon exposure to UV light.

8. The optical system of claim 1, wherein the window polarizer is an absorptive polarizer or a reflective polarizer.

9. The optical system of claim 1, wherein the window polarizer is a wide band polarizer.

10. The optical system of claim 1, wherein the window polarizer is a narrow band polarizer.

11. The optical system of claim 1, wherein the EAP comprises an active absorptive polarizer.

12. The optical system of claim 11, wherein the active absorptive polarizer has a wide band absorbance.

13. The optical system of claim 11, wherein the active absorptive polarizer has a narrow band absorbance.

14. The optical system of claim 1, wherein the EAP comprises a stack of two or more active absorptive polarizers.

15. The optical system of claim 14, wherein at least two of the active absorptive polarizers of the stack have different spectral absorption profiles.

16. The optical system of claim 14, wherein at least two of the active absorptive polarizers of the stack have substantially the same spectral absorption profile.

17. The optical system of claim 1, wherein the EAP comprises an electronic polarization rotator.

18. The optical system of claim 1, wherein the window polarizer and the EAP each absorb or reflect substantially the same region of electromagnetic radiation.

19. The optical system of claim 1, wherein the window polarizer and the EAP absorb or reflect different but overlapping regions of electromagnetic radiation.

20. The optical system of claim 1 , wherein the window polarizer and the EAP each absorb or reflect a radiation band chosen from: broadband, narrowband, or ultra narrowband radiation.

21. The optical system of claim 1, wherein the window forms part of a vehicle windshield, aircraft canopy, protective shield, a helmet, or a building structure.

22. The optical system of claim 1, wherein the EAP is incorporated into eyewear, goggles, or a visor worn by the viewer.

23. The optical system of claim 1, wherein the EAP comprises at least two individually controllable segments that receive the polarized environment light in spatially separate areas.

24. A method of using the optical system of claim 1, the method comprising switching the EAP from the non-attenuating state to the attenuating state.

25. A light protection optical system for attenuating environment light, the system comprising: a window disposed between a viewer and an environment including environment light within the visible spectrum comprising broadband radiation and narrowband radiation, the narrowband radiation having a peak wavelength, wherein the window comprises at least one narrow band window polarizer that preferentially attenuates a first polarization component (Pl) of environment light at the peak wavelength and preferentially transmits a second polarization component (P2) of environment light at the peak wavelength to produce a partially polarized environment light; and an electronically adjustable polarizer (EAP) disposed between the viewer and the window, wherein the EAP is configured to receive the partially polarized environment light, wherein, when electronically adjusted to produce an attenuating state, the EAP blocks at least 50% of the partially polarized environment light at the peak wavelength and transmits at least 20% of the partially polarized environment light at one or more wavelengths at least 50 nm away from the peak wavelength.

26. The optical system of claim 25, wherein the EAP blocks at least 80% of the partially polarized environment light at the peak wavelength and transmits at least 25% of the partially polarized environment light at one or more wavelengths at least 50 nm away from the peak wavelength.

27. The optical system of claim 25, wherein the EAP blocks at least 90% of the partially polarized environment light at the peak wavelength.

28. The optical system of claim 25, wherein the EAP is further configured to receive at least one display light from one or more information display systems, wherein the display light comprises at least a first polarization component (Pl) and optionally, a second polarization component (P2), wherein, when in the attenuating state, the EAP preferentially attenuates the optional second polarization components (P2) of display light while preferentially transmitting the first polarization component (Pl) of the display light such that at least 10% of display light incident on the EAP is transmitted as eye-entering display light.

29. The optical system of claim 28, wherein the information display system comprises an augmented reality display, a console, a control panel, or any combination thereof.

30. The optical system of claim 25, wherein the EAP comprises at least two individually controllable segments that receive the polarized environment light in spatially separate areas.

31. The optical system of claim 25, wherein the window forms part of a vehicle windshield, aircraft canopy, protective shield, a helmet, or a building structure, and wherein the EAP is incorporated into eyewear, goggles, or a visor worn by the viewer.

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