Augmented reality systems with dynamic see-through transmittance control

An augmented display system with dynamic see-through transmittance control is disclosed. The augmented display system includes: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen. The tandem EC filter includes a first window having a dominant first transmittance characteristic and a second window having a dominant second transmittance characteristic; and an augmented display transmittance controller configured to individually control the activation of the first window and the second window of the tandem EC filter, wherein the augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance; and apply appropriate drive voltage waveforms to the first window and the second window to achieve the determined transmittance.

TECHNICAL FIELD

Embodiments of the subject matter described herein relate generally to augmented display systems such as augmented reality systems. More particularly, embodiments of the subject matter relate to electronically adjustable filters for use with augmented display systems.

BACKGROUND

A current approach to achieving sunlight readability for augmented reality (AR) display systems is to increase the display brightness to very high levels (e.g., 1000 s of fL (foot-lambert)) to overpower the outside scene brightness to maintain adequate image contrast and readability. This brute force approach may lead to undesirably high power consumption and associated display heat dissipation issues, and display lifetime degradation issues. Use of visible spectrum, switchable optical windows to control the transmission of ambient light can obviate the need for increasing the AR display luminance to undesirably high levels. The desired characteristics of these switchable visible spectrum optical windows for sunlight readable AR display systems include high transmission (>60%), color neutrality in the visible wavelength band, long device lifetime, low power consumption and fast switching speed (˜1 second or less). The current electronic windows have either fast switching speed (e.g., GH-LC, guest-host liquid crystal-based windows with tens of millisecond switching speed) with limited dynamic transmittance range (e.g., <10:1), or high dynamic transmittance range (e.g., gel based electrochromic windows with >100:1 transmittance range) but very slow switching speed (e.g., 10 s of seconds). These limitations make them unsuitable for use in the AR display systems in high ambient lighting conditions such as direct sunlight without significant penalties related to power consumption, heat dissipation, and display lifetime degradation.

Hence, it is desirable to provide electronically switchable visible-spectrum optical windows with high dynamic transmittance range as well as fast switching speed. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.

SUMMARY

In one embodiment, an augmented display system with dynamic see-through transmittance control is disclosed. The augmented display system includes: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen. The tandem EC filter includes a first window having a dominant first transmittance characteristic and a second window having a dominant second transmittance characteristic; and an augmented display transmittance controller configured to individually control the activation of the first window and the second window of the tandem EC filter, wherein the augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance; and apply appropriate drive voltage waveforms to the first window and the second window to achieve the determined transmittance.

In another embodiment, an augmented display system with dynamic see-through transmittance control is disclosed. The augmented display system includes: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen, wherein the tandem EC filter includes a first window that provides a dynamic range of greater than 100:1 with a switching speed of around several seconds or more disposed over a second window with a switching speed of around several milliseconds or less and a dynamic transmittance range of around 10:1; and an augmented display transmittance system controller for individually controlling the activation of the first window and the second window of the EC tandem filter. The augmented display transmittance system controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance, activate only the second window to achieve the determined transmittance, for example through the application of an appropriate drive voltage waveform, when the determined transmittance can be achieved using only the second window, and activate both the first window and the second window, for example through the application of appropriate drive voltage waveforms, when the determined transmittance cannot be achieved using only the second window.

In another embodiment, an augmented display system with dynamic see-through transmittance control is disclosed. The augmented display system includes: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen, wherein the tandem EC filter includes a first window optimized for faster clearing (EC-C) and a second window optimized for faster darkening (EC-D); and an augmented display transmittance controller configured to individually control the activation of the first window and the second window of the tandem EC filter. The augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance and the direction of transition (e.g., darkening or clearing) for the selected augmented display luminance; and activate both the first window and the second window, for example through the application of appropriate drive voltage waveforms, to achieve the determined transmittance.

In another embodiment, an augmented display system with dynamic see-through transmittance control is disclosed. The augmented display system includes: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen wherein the tandem EC filter includes a gel-based EC window that provides a higher dynamic range (>100:1) but a slower switching speed (˜several seconds) laminated to a LC (Liquid Crystal) based electronic window with a faster switching speed (˜several milli-seconds) and a lower dynamic transmittance range (˜10:1); and an augmented display transmittance controller configured to individually control the activation of the EC window and the LC-based window of the EC tandem filter, wherein the augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the EC window and the LC-based window for a selected augmented display luminance, activate only the LC-based window to achieve the determined transmittance when the determined transmittance can be achieved using only the LC-based window, activate both the LC-based window and the EC window when the determined transmittance cannot be achieved using only the LC-based window, and activate both the LC-based window and the EC window, for example through the application of appropriate drive voltage waveforms.

In another embodiment, an augmented display system with dynamic see-through transmittance control is disclosed. The augmented display system includes: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen, wherein the tandem EC filter includes a first gel-based EC window optimized for faster clearing (EC-C) and a second gel-based EC window optimized for faster darkening (EC-D), wherein the composition of the EC gel and the EC cell design parameters in the EC-C window are optimized to achieve faster clearing and the EC gel and the EC cell design parameters in the EC-D window are optimized to achieve faster darkening times; and an augmented display transmittance controller configured to individually control the activation of the EC-C window and the EC-D window of the tandem EC filter, wherein the augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the EC-C window and the EC-D window for a selected augmented display luminance and the direction of transition (e.g., darkening or clearing) for the selected augmented display luminance, perform a darkening transition by: applying darkening drive voltage algorithms to the EC-D window and the EC-C window simultaneously, when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a darkening voltage drive algorithm to the EC-C window while applying a clearing drive voltage algorithm to the EC-D window until the EC-C window and the tandem EC filter reach the determined transmittance with the EC-D window at maximum transmittance wherein the EC-D window is clear and the EC-C window is controlling the transmittance; and perform a clearing transition by: applying clearing drive voltage algorithms to the EC-D window and the EC-C window simultaneously, and when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a clearing voltage drive algorithm to the EC-D window while applying a darkening drive voltage algorithm to the EC-C window until the tandem EC filter reaches the determined transmittance.

In another embodiment, a tandem electrochromic (EC) filter for use in an augmented display system with dynamic see-through transmittance control is disclosed. The tandem EC filter includes a first window that provides a dynamic range of greater than 100:1 with a switching speed of around several seconds or more disposed over a second window with a switching speed of around several milli-seconds or less and a dynamic transmittance range of around 10:1. The augmented display system includes an augmented display screen; the tandem EC filter disposed over the augmented display screen; and an augmented display transmittance system controller for individually controlling the activation of the first window and the second window of the EC tandem filter. The augmented display transmittance system controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance, activate only the second window to achieve the determined transmittance, for example through the application of an appropriate drive voltage waveform, when the determined transmittance can be achieved using only the second window, and activate both the first window and the second window, for example through the application of appropriate drive voltage waveforms, when the determined transmittance cannot be achieved using only the second window.

In another embodiment, a tandem electrochromic (EC) filter for use in an augmented display system with dynamic see-through transmittance control is disclosed. The tandem EC filter includes a first window optimized for faster clearing (EC-C) and a second window optimized for faster darkening (EC-D). The augmented display system includes: an augmented display screen; the tandem electrochromic EC filter disposed over the augmented display screen; and an augmented display transmittance controller configured to individually control the activation of the first window and the second window of the tandem EC filter. The augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance and the direction of transition (e.g., darkening or clearing) for the selected augmented display luminance; and activate both the first window and the second window, for example through the application of appropriate drive voltage waveforms, to achieve the determined transmittance.

Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the preceding background.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the application and uses. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, summary, or the following detailed description. As used herein, the term “module” refers to any hardware, software, firmware, electronic control component, processing logic, and/or processor device, individually or in any combination, including without limitation: application specific integrated circuit (ASIC), a field-programmable gate-array (FPGA), an electronic circuit, a processor (shared, dedicated, or group) and memory that executes one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.

The subject matter described herein discloses apparatus, systems, techniques and articles for providing electronically switchable visible spectrum optical windows that are capable of wide dynamic range control of the see-through (ambient) scene luminance and can enable sunlight readable augmented display systems (e.g., augmented reality (AR) display systems) with optimum image contrast of the augmented display against the scene luminance. The apparatus, systems, techniques and articles provided herein provide electronically switchable visible-spectrum optical windows with a high dynamic transmittance range as well as fast switching speed that can be used to render augmented display systems, such as AR display systems, useable in a broad range of external/ambient lighting conditions including direct sunlight. These electronically switchable visible-spectrum optical windows may also be used for a variety of other applications including military ground vehicles, and automotive and avionic HUDs. The apparatus, systems, techniques and articles provided herein can enable the use of see-through (e.g., wearable/head mounted) augmented display systems under a wide range of external ambient lighting conditions including direct sunlight. The apparatus, systems, techniques and articles provided herein can provide performance improvements for see-through augmented display systems with high power efficiency, without heat dissipation issues and device lifetime degradation issues. The apparatus, systems, techniques and articles provided herein are applicable to a broad set of augmented display applications including see-through augmented reality (AR) display systems, automotive and avionic heads up displays (HUDs), and military vehicle windows. The apparatus, systems, techniques and articles provided herein can achieve the objective of realizing a high dynamic range transmittance control and fast switching speed using a unique electrochromic (EC) optical filter structure and transmittance control algorithms.

FIG.1Ais a block diagram depicting an example tandem EC filter architecture100for an augmented display system. The example tandem EC filter architecture100comprises a gel-based electrochromic (EC) window102that provides a high dynamic range (>100:1) but slower switching speed (˜several seconds), laminated to a second electronic window104with a faster switching speed (˜several milli-seconds) and lower dynamic transmittance range (˜10:1) such as a Guest-Host LC (Liquid Crystal) device. The example tandem EC filter architecture100provides electronically switchable visible spectrum optical windows capable of wide dynamic range control of the see-through (ambient) scene luminance that can enable sunlight readable augmented display systems with optimum image contrast of the augmented display against the scene luminance.

FIG.1Bis a diagram containing graphs106,108,110and112that schematically illustrates example differences in dynamic transmittance ranges and switching speeds between an example EC filter102and an example LC filter104in the tandem EC filter architecture100. Graph106illustrates that an example gel-based EC window102may take several seconds to darken a scene viewed through the tandem EC filter architecture100through reducing the transmission of external light. Graph108illustrates that the example gel-based EC window102may take tens of seconds to lighten a scene viewed through the tandem EC filter architecture100through increasing the transmission of external light. Graph110illustrates that an example LC electronic window104may take tens of milliseconds to darken a scene viewed through the tandem EC filter architecture100through reducing the transmission of external light. Graph112illustrates that the example LC electronic window104may take tens of milliseconds to lighten a scene viewed through the tandem EC filter architecture100through increasing the transmission of external light. These graphs illustrate that the example LC electronic window104can begin the process of lightening or darkening a scene much quicker (milliseconds) than the example gel-based electrochromic window102(seconds).

The example tandem EC filter architecture100provides an electronically switchable visible-spectrum optical window with high dynamic transmittance range as well as fast switching speed, to enable augmented display systems, such as augmented reality (AR) systems, useable in the broad range of external lighting conditions including direct sunlight. These windows may also be used for a variety of other applications including military ground vehicles, and automotive and avionic HUDs.

FIG.2is a block diagram depicting an example augmented display system200that utilizes a tandem EC filter202disposed over an augmented display screen204(e.g., an augmented reality display screen, an aircraft or land vehicle HUD, and others). The example augmented display system200includes the tandem EC filter202disposed over an augmented display screen204and an augmented display transmittance system controller206coupled to an ambient light sensor208. The tandem EC filter202comprises a gel-based EC window102that provides a high dynamic range (>100:1) but slower switching speed (˜several seconds) laminated to a LC (Liquid Crystal) based electronic window104with a faster switching speed (˜several milli-seconds) and lower dynamic transmittance range (˜10:1). The example augmented display system200may also include an optional manual luminance and/or transmittance adjustment210for manually adjusting the brightness level applied to the augmented display screen204, and/or transmittance level applied to the EC filter202.

Output from the ambient light sensor208is used by the augmented display transmittance system controller206to determine the transmittance required from the switchable tandem EC filter202for a selected display luminance for the augmented display screen204for achieving a desired image contrast. If the commanded transmittance change can be accommodated by the LC filter104alone, then the augmented display transmittance system controller206can control the LC filter104alone to affect the required transmittance control very quickly (in a few 10 s of milli-sec). If the transmittance change required is larger than that which the LC filter104alone can achieve, both the by LC filter104and EC filter102are activated by the augmented display transmittance system controller206(e.g., by applying the appropriate/corresponding drive voltage waveforms). The augmented display transmittance system controller206can use this same transmittance control procedure both for window darkening as well as for window clearing transitions, because the LC filter104can switch an order of magnitude faster than the EC filter102can switch for both the darkening and clearing transitions.

The augmented display transmittance system controller206includes at least one processor and a computer-readable storage device or media encoded with programming instructions for configuring the controller206. The processor may be any custom-made or commercially available processor, a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), an auxiliary processor among several processors associated with the controller, a semiconductor-based microprocessor (in the form of a microchip or chip set), any combination thereof, or generally any device for executing instructions.

The computer readable storage device or media may include volatile and nonvolatile storage in read-only memory (ROM), random-access memory (RAM), and keep-alive memory (KAM), for example. KAM is a persistent or non-volatile memory that may be used to store various operating variables while the processor is powered down. The computer-readable storage device or media may be implemented using any of a number of known memory devices such as PROMs (programmable read-only memory), EPROMs (electrically PROM), EEPROMs (electrically erasable PROM), flash memory, or any other electric, magnetic, optical, or combination memory devices capable of storing data, some of which represent executable programming instructions, used by the controller206.

The augmented display transmittance system controller206is configured to individually control the of the EC window and the LC-based window of the EC tandem filter. In particular, the augmented display transmittance system controller206is configured to: determine from an ambient light sensor output the transmittance required from the EC window102and the LC-based window104for a selected augmented display luminance, activate the LC-based window104to achieve the determined transmittance when the determined transmittance can be achieved using only the LC-based window104, activate both the LC-based window104and the EC window102when the determined transmittance cannot be achieved using only the LC-based window104, and activate both the LC-based window104and the EC window102, for example, by applying appropriate drive voltage waveforms.

Thus, the example augmented display system200provides a tandem EC filter202that provides wide dynamic transmittance range using the EC filter102, and a fast response (e.g., ˜30 milli-sec) using the LC filter104. While the maximum transmittance of the tandem EC filter202is expected to be somewhat lower than that available from the single EC filter102alone, the tandem EC filter202nonetheless would provide a transmittance that is higher than a general transmittance requirement of >70%, as both the LC filter104and the EC filter102in the tandem EC filter202can achieve a transmittance of >85% with appropriate antireflection coatings applied.

FIG.3Ais a block diagram depicting an example tandem EC filter300for an augmented display system. The example tandem EC filter300comprises a stack of 2 electrochromic (EC) filters, a first filter (EC-C)302that is optimized for faster clearing and a second filter (EC-D)304that is optimized for faster darkening. By optimizing the composition of the EC gel and the EC cell design parameters, the design can be optimized to achieve either faster clearing or faster darkening times. The example tandem EC filter architecture300provides electronically switchable visible spectrum optical windows capable of wide dynamic range control of the see-through (ambient) scene luminance that can enable sunlight readable augmented display systems with optimum image contrast of the augmented display against the scene luminance.

FIG.3Bis a diagram containing graphs306,308,310and312that schematically illustrates example differences in dynamic transmittance ranges and switching speeds between the example first filter (EC-C)302and the example second filter (EC-D)304in the tandem EC filter architecture300. Graph306illustrates that an example first filter (EC-C)302may take tens of seconds to darken a scene viewed through the tandem EC filter architecture100through reducing the transmission of external light. Graph308illustrates that the example first filter (EC-C)302may take several seconds to lighten a scene viewed through the tandem EC filter architecture300through increasing the transmission of external light. Graph310illustrates that an example second filter (EC-D)304may take several seconds to darken a scene viewed through the tandem EC filter architecture300through reducing the transmission of external light. Graph312illustrates that the example second filter (EC-D)304may take several tens of seconds to lighten a scene viewed through the tandem EC filter architecture300through increasing the transmission of external light.

FIG.4is a block diagram depicting an example augmented display system400that utilizes a tandem EC filter402disposed over an augmented display screen404(e.g., an augmented reality display screen, an aircraft or land vehicle HUD, and others). The example augmented display system400includes the tandem EC filter402disposed over an augmented display screen404and an augmented display transmittance system controller406coupled to an ambient light sensor408. The tandem EC filter402comprises a first gel-based EC window (EC-C)302optimized for faster clearing and a second gel-based EC window (EC-D)304optimized for faster darkening, wherein the composition of the EC gel and the EC cell design parameters in the EC-C window are optimized to achieve faster clearing and the EC gel and the EC cell design parameters in the EC-D window are optimized to achieve faster darkening times. The example augmented display system400may also include an optional manual luminance and/or transmittance adjustment410for manually adjusting the brightness level applied to the augmented display screen404, and/or transmittance level applied to the EC filter402. Output from the ambient light sensor408is used by the augmented display transmittance system controller406to determine the transmittance required from the switchable tandem EC filter402for a selected display luminance for the augmented display screen404for achieving a desired image contrast.

The augmented display transmittance system controller406includes at least one processor and a computer-readable storage device or media encoded with programming instructions for configuring the controller406. The processor may be any custom-made or commercially available processor, a central processing unit (CPU), a graphics processing unit (GPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), an auxiliary processor among several processors associated with the controller, a semiconductor-based microprocessor (in the form of a microchip or chip set), any combination thereof, or generally any device for executing instructions.

The computer readable storage device or media may include volatile and nonvolatile storage in read-only memory (ROM), random-access memory (RAM), and keep-alive memory (KAM), for example. KAM is a persistent or non-volatile memory that may be used to store various operating variables while the processor is powered down. The computer-readable storage device or media may be implemented using any of a number of known memory devices such as PROMs (programmable read-only memory), EPROMs (electrically PROM), EEPROMs (electrically erasable PROM), flash memory, or any other electric, magnetic, optical, or combination memory devices capable of storing data, some of which represent executable programming instructions, used by the controller406.

The augmented display transmittance system controller406is configured to individually control the first filter (EC-C)302and the second filter (EC-D)304of the EC tandem filter402. In particular, the augmented display transmittance system controller406is configured to: determine from an ambient light sensor output the transmittance required from the EC-C window302and the EC-D window304for a selected augmented display luminance and the direction of transition (e.g., darkening or clearing), for the selected augmented display luminance, and apply an appropriate darkening algorithm or lightening algorithm to control the activation of the first filter (EC-C)302and the second filter (EC-D)304of the EC tandem filter402.

To perform a darkening transition, the augmented display transmittance system controller406is configured to: apply darkening drive voltage algorithms to the EC-D window304and the EC-C window302simultaneously; and when the transmittance value of the tandem EC filter402approaches close to the determined transmittance, continue applying a darkening voltage drive algorithm to the EC-C window302while applying a clearing drive voltage algorithm to the EC-D304window until the EC-C window302and the tandem EC filter402reach the determined transmittance with the EC-D window304at maximum transmittance wherein the EC-D window304is clear and the EC-C window302is controlling the transmittance. This will allow for faster clearing using the EC-C window if clearing is subsequently desired.

To perform a clearing transition, the augmented display transmittance system controller406is configured to: apply clearing drive voltage algorithms to the EC-D window304and the EC-C window302simultaneously; and when the transmittance value of the tandem EC filter402approaches close to the determined transmittance, continue applying a clearing voltage drive algorithm to the EC-D window304while applying a darkening drive voltage algorithm to the EC-C window302until the tandem EC filter402reaches the determined transmittance.

FIG.5is a process flow chart depicting an example process500in an example augmented display system for achieving wide dynamic range transmittance control as well as fast switching. In the example process500, the ambient light sensor input is used to determine the transmittance change required as well as the direction of transition (darkening or clearing), for a selected augmented display luminance (operation502).

When a darkening transition is required, the example process500includes applying darkening drive voltage algorithms to the EC-D filter and EC-C filter simultaneously (operations504). As the stack transmittance value approaches close to the commanded value, the example processes500continuing to apply a darkening voltage drive algorithm to the EC-C filter, while applying a clearing drive voltage algorithm to the EC-D filter, such that the EC-C filter (and the stack) reaches the targeted lower transmittance condition with the EC-D filter at a maximum transmittance condition. At this condition, the EC-D filter is clear, and the EC-C filter controls the dark state stack transmittance until the next change is commanded. As the tandem EC device transitions to the commanded lower transmittance level, at a fast speed, aided by a fast darkening time of the EC-D filter, both the EC-C filter and the EC-D filter are placed respectively under lower and higher transmittance conditions. In this condition the tandem EC device can respond to further clearing or darkening transition commands, at a fast speed.

When a clearing transition is required, the example process500includes applying selected clearing drive voltage algorithms to the EC-C filter and the EC-D filter simultaneously. As the transmittance approaches close to the commanded value, the example processes500includes continuing to apply a clearing voltage drive algorithm to the EC-D filter such that it reaches a targeted transmittance value, while a darkening voltage drive algorithm is applied to the EC-C filter until the desired stack transmittance is achieved. At the time the tandem EC device is switched to its commanded transmittance condition, both the EC-D filter and the EC-C filter are placed in a condition to switch fast upon subsequent commands for either clearing or darkening transitions.

Detailed drive algorithms can be optimized for the EC-C filter and the EC-D filter in the stack to transition the stack transmittance from any transmittance to any other desired transmittance level (from fully dark to fully clear and vice versa) with a fast switching speed. As an additional level of augmented system optimization particularly for use in on-the-move operations (during mounted or dismounted operations) and rapidly changing ambient light conditions (such as in entering a cave or exiting a cave), multiple light sensors may be used to detect external (ambient) light conditions near and far with light sensors aimed at the near range and at a distant (upcoming) range, to prepare the EC filter stack for enhanced response time.

Described herein are apparatus, systems, techniques and articles for providing electronically switchable visible spectrum optical windows capable of wide dynamic range control of the see-through (ambient) scene luminance that can enable sunlight readable augmented display systems with optimum image contrast of the augmented display against the scene luminance. In one embodiment, an augmented display system with dynamic see-through transmittance control is provided. The augmented display system comprises: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen. The tandem EC filter comprises a first window having a dominant first transmittance characteristic and a second window having a dominant second transmittance characteristic; and an augmented display transmittance controller configured to individually control the activation of the first window and the second window of the tandem EC filter, wherein the augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance; and apply appropriate drive voltage waveforms to the first window and the second window to achieve the determined transmittance.

These aspects and other embodiments may include one or more of the following features. The dominant first transmittance characteristic may comprise a dynamic range of greater than 100:1. The dominant second transmittance characteristic may comprise a switching speed of around several milli-seconds or less. The tandem EC filter may comprise a first window that provides a dynamic range of greater than 100:1 with a switching speed of around several seconds or more disposed over a second window with a switching speed of around several milli-seconds or less and a dynamic transmittance range of around 10:1. The augmented display transmittance system controller may be configured to activate only the second window to achieve the determined transmittance, for example through the application of an appropriate drive voltage waveform, when the determined transmittance can be achieved using only the second window. The augmented display transmittance system controller may be configured to activate both the first window and the second window, for example through the application of appropriate drive voltage waveforms, when the determined transmittance cannot be achieved using only the second window. The first window may comprise a gel-based EC window. The second window may comprise a LC (Liquid Crystal) based electronic window. The dominant first transmittance characteristic may comprise faster clearing. The dominant second transmittance characteristic may comprise faster darkening. The augmented display transmittance system controller may be configured to determine from an ambient light sensor output the direction of transition (e.g., darkening or clearing) for the selected augmented display luminance. The first window may comprise a first gel-based EC window optimized for faster clearing (EC-C) wherein the composition of the EC gel and the EC cell design parameters in the first window are optimized to achieve faster clearing. The second window may comprise a second gel-based EC window optimized for faster darkening (EC-D) wherein the composition of the EC gel and the EC cell design parameters in the second window are optimized to achieve faster darkening times. The augmented display transmittance controller may be configured to perform a darkening transition by: applying darkening drive voltage algorithms to the EC-D window and the EC-C window simultaneously; and when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a darkening voltage drive algorithm to the EC-C window while applying a clearing drive voltage algorithm to the EC-D window until the EC-C window and the tandem EC filter reach the determined transmittance with the EC-D window at maximum transmittance wherein the EC-D window is clear and the EC-C window is controlling the transmittance. The augmented display transmittance controller may be configured to perform a clearing transition by: applying clearing drive voltage algorithms to the EC-D window and the EC-C window simultaneously, and when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a clearing voltage drive algorithm to the EC-D window while applying a darkening drive voltage algorithm to the EC-C window until the tandem EC filter reaches the determined transmittance.

In another embodiment, an augmented display system with dynamic see-through transmittance control is provided. The augmented display system comprises: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen, wherein the tandem EC filter comprises a first window that provides a dynamic range of greater than 100:1 with a switching speed of around several seconds or more disposed over a second window with a switching speed of around several milli-seconds or less and a dynamic transmittance range of around 10:1; and an augmented display transmittance system controller for individually controlling the activation of the first window and the second window of the EC tandem filter. The augmented display transmittance system controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance, activate only the second window to achieve the determined transmittance, for example through the application of an appropriate drive voltage waveform, when the determined transmittance can be achieved using only the second window, and activate both the first window and the second window, for example through the application of appropriate drive voltage waveforms, when the determined transmittance cannot be achieved using only the second window.

These aspects and other embodiments may include one or more of the following features. The first window may comprise a gel-based EC window. The second window may comprise an LC (Liquid Crystal) based electronic window. The tandem EC filter may comprise a gel-based EC window laminated to an LC based electronic window.

In another embodiment, an augmented display system with dynamic see-through transmittance control is provided. The augmented display system comprises: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen, wherein the tandem EC filter comprises a first window optimized for faster clearing (EC-C) and a second window optimized for faster darkening (EC-D); and an augmented display transmittance controller configured to individually control the activation of the first window and the second window of the tandem EC filter. The augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance and the direction of transition (e.g., darkening or clearing) for the selected augmented display luminance; and activate both the first window and the second window, for example through the application of appropriate drive voltage waveforms, to achieve the determined transmittance.

These aspects and other embodiments may include one or more of the following features. The first window may comprise a first gel-based EC window optimized for faster clearing (EC-C) wherein the composition of the EC gel and the EC cell design parameters in the first window are optimized to achieve faster clearing. The second window may comprise a second gel-based EC window optimized for faster darkening (EC-D) wherein the composition of the EC gel and the EC cell design parameters in the second window are optimized to achieve faster darkening times. The augmented display transmittance controller may be configured to perform a darkening transition by: applying darkening drive voltage algorithms to the EC-D window and the EC-C window simultaneously; and when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a darkening voltage drive algorithm to the EC-C window while applying a clearing drive voltage algorithm to the EC-D window until the EC-C window and the tandem EC filter reach the determined transmittance with the EC-D window at maximum transmittance wherein the EC-D window is clear and the EC-C window is controlling the transmittance. The augmented display transmittance controller may be configured to perform a clearing transition by: applying clearing drive voltage algorithms to the EC-D window and the EC-C window simultaneously, and when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a clearing voltage drive algorithm to the EC-D window while applying a darkening drive voltage algorithm to the EC-C window until the tandem EC filter reaches the determined transmittance.

In another embodiment, an augmented display system with dynamic see-through transmittance control is provided. The augmented display system comprises: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen wherein the tandem EC filter comprises a gel-based EC window that provides a higher dynamic range (>100:1) but a slower switching speed (˜several seconds) laminated to a LC (Liquid Crystal) based electronic window with a faster switching speed (˜several milli-seconds) and a lower dynamic transmittance range (˜10:1); and an augmented display transmittance controller configured to individually control the activation of the EC window and the LC-based window of the EC tandem filter, wherein the augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the EC window and the LC-based window for a selected augmented display luminance, activate only the LC-based window to achieve the determined transmittance when the determined transmittance can be achieved using only the LC-based window, activate both the LC-based window and the EC window when the determined transmittance cannot be achieved using only the LC-based window, and activate both the LC-based window and the EC window, for example through the application of appropriate drive voltage waveforms.

In another embodiment, an augmented display system with dynamic see-through transmittance control is provided. The augmented display system comprises: an augmented display screen; a tandem electrochromic (EC) filter disposed over the augmented display screen, wherein the tandem EC filter comprises a first gel-based EC window optimized for faster clearing (EC-C) and a second gel-based EC window optimized for faster darkening (EC-D), wherein the composition of the EC gel and the EC cell design parameters in the EC-C window are optimized to achieve faster clearing and the EC gel and the EC cell design parameters in the EC-D window are optimized to achieve faster darkening times; and an augmented display transmittance controller configured to individually control the activation of the EC-C window and the EC-D window of the tandem EC filter, wherein the augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the EC-C window and the EC-D window for a selected augmented display luminance and the direction of transition (e.g., darkening or clearing) for the selected augmented display luminance, perform a darkening transition by: applying darkening drive voltage algorithms to the EC-D window and the EC-C window simultaneously, when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a darkening voltage drive algorithm to the EC-C window while applying a clearing drive voltage algorithm to the EC-D window until the EC-C window and the tandem EC filter reach the determined transmittance with the EC-D window at maximum transmittance wherein the EC-D window is clear and the EC-C window is controlling the transmittance; and perform a clearing transition by: applying clearing drive voltage algorithms to the EC-D window and the EC-C window simultaneously, and when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a clearing voltage drive algorithm to the EC-D window while applying a darkening drive voltage algorithm to the EC-C window until the tandem EC filter reaches the determined transmittance.

In another embodiment, a tandem electrochromic (EC) filter for use in an augmented display system with dynamic see-through transmittance control is provided. The tandem EC filter comprises a first window that provides a dynamic range of greater than 100:1 with a switching speed of around several seconds or more disposed over a second window with a switching speed of around several milli-seconds or less and a dynamic transmittance range of around 10:1. The augmented display system comprises an augmented display screen; the tandem EC filter disposed over the augmented display screen; and an augmented display transmittance system controller for individually controlling the activation of the first window and the second window of the EC tandem filter. The augmented display transmittance system controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance, activate only the second window to achieve the determined transmittance, for example through the application of an appropriate drive voltage waveform, when the determined transmittance can be achieved using only the second window, and activate both the first window and the second window, for example through the application of appropriate drive voltage waveforms, when the determined transmittance cannot be achieved using only the second window.

These aspects and other embodiments may include one or more of the following features. The first window may comprise a gel-based EC window. The second window may comprise a LC (Liquid Crystal) based electronic window. The tandem EC filter may comprise a gel-based EC window laminated to a LC based electronic window.

In another embodiment, a tandem electrochromic (EC) filter for use in an augmented display system with dynamic see-through transmittance control is provided. The tandem EC filter comprises a first window optimized for faster clearing (EC-C) and a second window optimized for faster darkening (EC-D). The augmented display system comprises: an augmented display screen; the tandem electrochromic EC filter disposed over the augmented display screen; and an augmented display transmittance controller configured to individually control the activation of the first window and the second window of the tandem EC filter. The augmented display transmittance controller is configured to: determine from an ambient light sensor output the transmittance required from the first window and the second window for a selected augmented display luminance and the direction of transition (e.g., darkening or clearing) for the selected augmented display luminance; and activate both the first window and the second window, for example through the application of appropriate drive voltage waveforms, to achieve the determined transmittance.

These aspects and other embodiments may include one or more of the following features. The first window may comprise a first gel-based EC window optimized for faster clearing (EC-C) wherein the composition of the EC gel and the EC cell design parameters in the first window are optimized to achieve faster clearing. The second window may comprise a second gel-based EC window optimized for faster darkening (EC-D) wherein the composition of the EC gel and the EC cell design parameters in the second window are optimized to achieve faster darkening times. The augmented display transmittance controller may be configured to perform a darkening transition by: applying darkening drive voltage algorithms to the EC-D window and the EC-C window simultaneously; and when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a darkening voltage drive algorithm to the EC-C window while applying a clearing drive voltage algorithm to the EC-D window until the EC-C window and the tandem EC filter reach the determined transmittance with the EC-D window is at maximum transmittance wherein the EC-D window is clear and the EC-C window is controlling the transmittance. The augmented display transmittance controller may be configured to perform a clearing transition by: applying clearing drive voltage algorithms to the EC-D window and the EC-C window simultaneously, and when the transmittance value of the tandem EC filter approaches close to the determined transmittance, continue applying a clearing voltage drive algorithm to the EC-D window while applying a darkening drive voltage algorithm to the EC-C window until the tandem EC filter reaches the determined transmittance.