Dual active film electrochromic display device

Abstract

A dual active electrochromic device is a combination of at least two working electrodes that contain electrochromic materials and at least one counter electrode where the potentials between each working electrode and a counter electrode are independently supplied. No more than one electrode is reflective. The color of the device results from the additive color of the electrochromic materials and varies according to the potentials applied independently. The electrochromic materials can be electrochromic polymers that are deposited as film on substrates to form the working electrodes. The electrochromic device can be used for display or window applications.

Description

Background technique [0001] Electrochromism is a color change of a material caused by an electrochemical oxidation or reduction reaction. Some electrochromic materials switch reproducibly between chromatic and achromatic states, while others exhibit polychromatic states. Conjugated electroactive polymers are electrochromic materials in which the achievable colors span the entire visible region of the electromagnetic spectrum. In addition, the polymers have electrochromic activation beyond the visible in the ultraviolet, near-infrared, far-infrared and microwave regions of the spectrum. The electrochromism of conjugated electroactive polymers arises from electronic transitions in neutral polymers and those generated during oxidation or reduction. The color of the neutral state of a polymer is determined by the energy difference between the highest occupied molecular orbital (HOMO) making up the valence band and the lowest unoccupied molecular orbital (LUMO) making up the cond...

AI Technical Summary

Problems solved by technology

[0004] Although conjugated conducting polymers offer a large color palette in addition to the transmissive state, the displayed colors in electrochromic devices combining these polymers are generally limited to two states, and it is currently not possible to systematically control a large number of colors.

Given the simultaneous switching of cathodically and anodically colored polymers in additive color combinations in absorbing / transmitting electrochromic devices, many of the currently displayed colors are not particularly suitable for display devices

Additionally, current devices generally do not allow switching between the multicolor state and the transmissive state

Such color control is even more unavailable for reflective devices where only the color of a single electroactive polymer is available

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