Electro-optic element with integrated capacitive touch screen functionality
Inventors
Turnbull, Robert R. • Niu, Xiaoxu
Assignees
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Publication Number
US-12443064-B2
Publication Date
2025-10-14
Expiration Date
Abstract
An electro-optic element including: (i) an electrochromic medium; (a) a first electro-optic conductive layer that is substantially transparent disposed to one side of the electrochromic medium; (b) a second electro-optic conductive layer disposed to another side of the electrochromic medium; (c) a capacitive touchscreen conductive layer disposed on an opposite side of the first electro-optic conductive layer as the electrochromic medium, the capacitive touchscreen conductive layer comprising a pattern and being substantially transparent; (d) a capacitive touchscreen insulating layer disposed between the capacitive touchscreen conductive layer and the first electro-optic conductive layer; and (e) electrical circuitry configured (i) to drive the capacitive touchscreen conductive layer and at least one of the first electro-optic conductive layer and the second electro-optic conductive layer together with substantially in-phase AC voltage and (ii) to provide an input DC voltage difference between the first electro-optic conductive layer and second electro-optic conductive layer is substantially constant.
Core Innovation
An electro-optic element integrates an electrochromic medium between a first electro-optic conductive layer and a second electro-optic conductive layer. The first electro-optic conductive layer is substantially transparent and disposed to one side of the electrochromic medium, while the second electro-optic conductive layer is disposed to another side of the electrochromic medium. A capacitive touchscreen conductive layer that comprises a pattern and is substantially transparent is disposed on an opposite side of the first electro-optic conductive layer as the electrochromic medium.
The electro-optic element further includes a capacitive touchscreen insulating layer disposed between the capacitive touchscreen conductive layer and the first electro-optic conductive layer. Electrical circuitry drives the capacitive touchscreen conductive layer and at least one of the first electro-optic conductive layer and the second electro-optic conductive layer together with substantially in-phase alternating current (AC) voltage. Simultaneously, the circuitry provides an input DC voltage difference between the first electro-optic conductive layer and the second electro-optic conductive layer that is substantially constant through all points in time of a sampled period of time for a set level of optical transmission through the electrochromic medium.
The described circuitry electrically isolates the electro-optic conductive layers from touchscreen-ground effects at a selected AC frequency or frequency range, thereby reducing capacitive loading and improving signal-to-noise ratio and touch sensitivity. The document also describes operating behavior using in-phase AC waveforms while maintaining a substantially constant, in-phase DC voltage difference to preserve electrochromic operation and set optical transmission.
Claims Coverage
The document includes two independent claims. Across these claims, the inventive features focus on an electro-optic element architecture that integrates a patterned, substantially transparent capacitive touchscreen layer with an electrochromic stack, and on an operating drive scheme that uses substantially in-phase AC with a substantially constant DC voltage difference, including electrically isolating the electro-optic conductive layers via a frequency selection.
Electro-optic stack with transparent electrochromic electrodes and patterned capacitive touchscreen
An electro-optic element comprising an electrochromic medium, a first substantially transparent electro-optic conductive layer disposed to one side of the electrochromic medium, a second electro-optic conductive layer disposed to another side of the electrochromic medium, and a patterned substantially transparent capacitive touchscreen conductive layer disposed on an opposite side of the first electro-optic conductive layer as the electrochromic medium
Capacitive touchscreen insulating layer between touchscreen conductive and electro-optic electrode
A capacitive touchscreen insulating layer disposed between the capacitive touchscreen conductive layer and the first electro-optic conductive layer
In-phase AC drive with substantially constant DC difference for set optical transmission
Electrical circuitry configured to drive the capacitive touchscreen conductive layer and at least one of the first electro-optic conductive layer and the second electro-optic conductive layer together with substantially in-phase alternating current (AC) voltage while simultaneously providing an input DC voltage difference between the first electro-optic conductive layer and the second electro-optic conductive layer that is substantially constant through all points in time of a sampled period of time for a set level of optical transmission
Electrically isolate electro-optic conductive layers by driving at a selected AC frequency or range
Driving the first electro-optic conductive layer and the second electro-optic conductive layer at a frequency or range of frequencies that electrically isolates the first electro-optic conductive layer and the second electro-optic conductive layer
Overall, the independent claims cover an electrochromic electro-optic element integrating a patterned, substantially transparent capacitive touchscreen layer separated by a capacitive touchscreen insulating layer, together with circuitry that drives touchscreen and electro-optic conductive layers using substantially in-phase AC while maintaining a substantially constant DC voltage difference for set optical transmission, and driving at a selected AC frequency or range to electrically isolate the electro-optic conductive layers.
Stated Advantages
Improves signal-to-noise ratio (SNR) and touch sensitivity.
Preserves electrochromic operation by maintaining a substantially constant, in-phase DC voltage difference while using substantially in-phase AC voltages.
Reduces capacitive loading by electrically isolating the electro-optic conductive layers from touchscreen-ground effects at a selected AC frequency or frequency range.
Documented Applications
Use in operating an electro-optic element that integrates an electrochromic medium with a capacitive patterned touchscreen and circuitry that drives the touchscreen and electro-optic electrodes with in-phase AC while maintaining an optical transmission set level.
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