Color Control in π-Conjugated Organic Polymers for Use in Electrochromic Devices

Head-worn display design is inherently an interdisciplinary subject fusing optical engineering, optical materials, optical coatings, electronics, manufacturing techniques, user interface design, computer science, human perception, and physiology for assessing these displays. This paper summarizes the state-of-the-art in head-worn display design (HWD) and development. This review is focused on the optical engineering aspects, divided into different sections to explore principles and applications. Building on the guiding fundamentals of optical design and engineering, the principles section includes a summary of microdisplay or laser sources, the Lagrange invariant for understanding the trade-offs in optical design of HWDs, modes of image presentation (i.e., monocular, biocular, and stereo) and operational modes such as optical and video see-through. A brief summary of the human visual system pertinent to the design of HWDs is provided. Two optical design forms, namely, pupil forming and non-pupil forming are discussed. We summarize the results from previous design work using aspheric, diffractive, or holographic elements to achieve compact and lightweight systems. The applications section is organized in terms of field of view requirements and presents a reasonable collection of past designs

Head-worn displays: a review

Head-worn adaptive display

An eyepiece includes a mechanical frame adapted to secure a lens and an image source facility above the lens. The image source facility includes an LED, a planar illumination facility and a reflective display. The planar illumination facility converts a light beam from the LED received on a side of the planar illumination facility into a top emitting planar light source, uniformly illuminates the reflective display, and is substantially transmissive to allow reflected light to pass through towards a beam splitter. The beam splitter is positioned to receive the image light and to reflect a portion onto a mirrored surface. The mirrored surface is positioned and shaped to reflect the image light into an eye of a user of the eyepiece thereby providing an image within a field of view, the mirrored surface further adapted to be partially transmissive within an area of image reflectance.

Eyepiece with uniformly illuminated reflective display

An interactive head-mounted eyepiece with an integrated processor for handling content for display and an integrated image source for introducing the content to an optical assembly through which the user views a surrounding environment and the displayed content, wherein the height of the image source is at least 80% of a display active area width of the optical assembly.

See-through near-eye display glasses with a small scale image source

Optimization, preparation, and electrical short evaluation for 30 cm2 active area dual conjugated polymer electrochromic windows

High contrast solid-state electrochromic devices from substituted 3,4-propylenedioxythiophenes using the dual conjugated polymer approach

An electrochromic cell is disclosed which can include a first electrically conducting transparent electrode bonded to an electrochemically formed first electrochromic electrode on the surface of the electrode; a second electrically conducting transparent electrode bonded to an electrochemically formed second electrochromic electrode on the surface of the second electrode and a transparent gel polymer electrolyte formed from one or more macromomoners mixed with a plasticizer and an electrolyte salt, the gel polymer electrolyte in contact with both the first and second electrochromic electrodes; the first and second electrochromic electrodes are separated from each other.

Gel polymer electrolytes

An electrochromic cell of the present invention may include a first electrically conducting transparent electrode bonded to an electrochemically formed first electrochromic electrode on the surface of the electrode; a second electrically conducting transparent electrode bonded to an electrochemically formed second electrochromic electrode on the surface of the second electrode and a transparent gel polymer electrolyte formed from one or more macromomoners mixed with a plasticizer and an electrolyte salt, the gel polymer containing ionic liquids in contact with both the first and second electrochromic electrodes; the first and second electrochromic electrodes are separated from each other

Gel polymers containing ionic liquids

Complementary coloring conducting polymer based electrochromic devices have been designed, fabricated and tested for possible application as a variable attenuation combiner element for a see-through head mounted display or a variable trasnsmissive sand wind dust goggle lens. Electrochromic cells fabricated on both glass and polycarbonate substrates have been demonstrated to meet closely the desired goals of low power consumption, wide transmission range, fast switching speeds and long lifetime. Photopic transmissions of 34% in colored state and 67% in bleached state were achieved in a reproducible manner. The measured switching times are 0.6 sec (colored to bleached state) and 1.9 sec (bleached to colored state). The life cycle testing showed stability up to 92,000 switches. The measured power consumption of the fabricated devices was < 1 mW/cm . The electrochromic technology design effort has identified processes for obtaining the optimum layer thickness and selecting polymers and gel electrolytes necessary to obtain the widest transmission range, fastest switching speed and longest lifetime. Early environmental testing has been performed by subjecting prototype electrochromic cells to temperatures varying from -30°C to + 40°C with the results reported herein. Follow on work includes further optimization of electronic drive schemes as well as field testing of electrochromic lens equipped sand, wind dust goggles.

Bijan Radmard

Papers

Optimization, preparation, and electrical short evaluation for 30 cm2 active area dual conjugated polymer electrochromic windows

High contrast solid-state electrochromic devices from substituted 3,4-propylenedioxythiophenes using the dual conjugated polymer approach

Gel polymer electrolytes

Gel polymers containing ionic liquids

Electrochromic variable transmission optical combiner