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Ultrawide Transmission Range for Variable Transmission Eyewear (VTE)


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Directed Energy, Microelectronics OBJECTIVE: An active, variable transmission eyewear on a ballistic substrate with ultrawide transmission range that can switch reversibly and automatically between high (≥70%) and low-transmission states. DESCRIPTION: Soldiers are subjected to quickly changing light conditions, such as inside a dark building versus outside in the sun, within a single mission. The pupil can take a few 10s of seconds to fully acclimate to changing light levels [1]. Additionally, low-energy laser threats such as dazzlers are encountered in the field [2]. Soldiers already have issued (approved) variable transmission eyewear (VTE) on the Authorized Protective Eyewear List (APEL), but the current systems do not provide the required transmission range in a single lens. These are the e-Tint CTRL MS1 Spectacle and the e-Tint CTRL MG1 Goggle. Due to insufficient transmission range, these two designs are currently being fielded with both a variable transmission lens (for use in variable lighting conditions encountered during daytime operations, such as going in and out of buildings) and a standard, high transmittance clear lens for nighttime operations. Based on Soldier feedback during testing, the decision to field a standard clear lens in conjunction with the transition lens was made by eye protection subject matter experts at Product Manager Soldier Protective Equipment. Soldiers commented that the transition lens was too dark for nighttime use [3]. In addition, this creates undue cognitive burden on the Soldier decreasing their situational awareness. In addition, Soldiers may choose to forgo the protection altogether, which puts their eyes at even higher risk. A solution to this problem is active variable transmission eyewear with ultrawide transmission range, i.e., from 10% to 70%, or more, transmission. Previous efforts at active VTE have struggled to achieve much higher than 60% clear state transmission as certain layers have contributed to high parasitic optical losses. VTE with very low transmission in the dark state can also function as laser eye protection for low-energy threats. The proposed VTE solution should address the following requirements. Variable transmission prototypes must be manufacturable on a ballistic substrate and continue to provide other eyewear functions including anti-fragmentation, anti-scratch, anti-fog, and anti-ballistic. Variable transmission proposals should retain high optical quality. Approaches should be color neutral. While an eyewear is not required in the early Phases, proposals should keep an eye on technologies and approaches amenable to the eyewear platform. Proposals should either have a roadmap to meet or exceed the standard fielded U.S. military combat eye protection requirements, per MIL-PRF-32432. The VTE must reversibly switch repeatedly. It should go to clear state (high transmission) when powered off or fails. Active VTE prototypes should be aware of power needs of proposed solution and work to minimize power requirements. For instance, if a battery is part of a submitted design, then a single charge should last at least 72 hours and be fully borne on the eyewear frame. Ideally switching times should be less than a second, with 250 ms being the objective. Comfort of the VTE should be considered which includes weight, distribution of mass, retention on face, and compatibility with other headgear. PHASE I: During Phase I, the contractor shall research and develop innovative approaches to ultrawide variable transmission. Proposed solutions should exceed current variable transmission range of 12—65%. Proposed solutions must show how they can achieve higher than 70% clear-state transmission in a single lens. Proposed solutions must be amenable to military relevant eyewear substrates. For the purposes of Phase I, demonstrations may include switchable devices and/or eyewear prototypes that exhibit active variable transmission. Through Phase I, the contractor should provide monthly progress reports detailing technical and programmatic results. End products shall include an end-of-phase report with conceptual drawings and a proof-of-concept prototype. End-of-phase report shall include, but not limited to, the following: variable transmission range achieved, power consumption, switching speed, color appearance (i.e., chromaticity), construction of lens and variable transmission layers, electronic schematics, material composition. Ability to enhance situational awareness and increase lethality while preserving existing vision protection capabilities (i.e., be equal to or better than standard fielded U.S. military combat eye protection, per MIL-PRF-32432) should be supported with sound reasoning and substantial evidence. PHASE II: During Phase II contractor shall address in detail the technical approach and design of the technology chosen in Phase I. Engineering challenges associated with the technological approach should be noted. Minimum required deliverable for the Phase II shall be a switchable active variable transmission eyewear prototype. Dark state transmission should be equal to or less than 15%. Target clear state transmission is greater than 85%. Prototype shall be on a military relevant substrate. Power shall be on-board prototype. Technical report shall detail optical characteristics (including transmission range and ANSI Z87.1 optical performance), electrical and power characteristics (including power consumed, battery life), and testing associated with MIL-PRF-32432 (i.e., ballistic fragmentation, anti-scratch). PHASE III DUAL USE APPLICATIONS: The end-state of this technology is for a single combat eye protection for all levels of illumination and provide some protection against laser dazzler threats. Further potential military applications include other headgear platforms that have a need for VTE. Civilian markets for this technology include law enforcement operations, environmental and agricultural markets, and outdoor recreational uses REFERENCES: 1. ANSI/ISEA Z87.1-2015 American National Standard Occupational and Educational Personal Eye and Face Protection Devices 2. MIL-PRF-32432A, Performance Specification: Military Combat Eye Protection System 3. Authorized Protective Eyewear List (APEL) 4. ATC-11772, "Developmental Test (DT) of the Soldier Protection System (SPS) Human Factors Assessment II (HFA 2) Transition Combat Eye Protection (TCEP) System", Richardson, Elizabeth N., Gearin, Steven G., (2015) KEYWORDS: Eyewear; variable transmission; laser protection; PPE
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