Printed Electronics card with piezo-powered indicator

I came across a recently granted patent that describes a printed card such as a business card with a display that is powered by a built-in piezo power source. This is a neat printed electronics application that gets around the problem of needing a battery to operate any device such as an indicator or display printed on the substrate. Although there are “printed electronics” batteries they tend to require encapsulated electrolytes to fabricate them and so are not entirely compatible with low-cost printing processes.

The patent is US8959734 and was published on 24th Feb 2015. It has a priority date of 16th Dec 2010. Details of the inventors and assignee are summarised below along with the abstract:

Inventors: Daniel; Jurgen H. (San Francisco, CA), Ng; Tse Nga (Mountain View, CA)

Assignee: Palo Alto Research Center Incorporated (Palo Alto, CA)

Abstract

An interactive card or the like employs a piezoelectric charge generator (piezo-strip) for temporarily driving an indicator. The piezo-strip may be displaced (bent) in order to generate charge to drive the indicator. Printed electronic processes are utilized to produce the indicator and/or the piezoelectric charge generator. An indicator is formed on a substrate by way of a printed electronics process. A displaceable region of piezoelectric material associated with the said substrate is formed by way of a printed electronics process. Electrical interconnections are formed on said substrate by way of a printed electronics process. The electrical interconnections connecting said indicator and said first region of piezoelectric material such that displacement of said first region of piezoelectric material generates a voltage therein that is provided to said indicator in order to actuate said indicator and thereby indicate the displacement of said first region of piezoelectric material.

The drawings give a pretty good idea of the invention and its construction. I’ve reproduced two sets of figures below to show this but there are more in the patent that you can view.

Fig1_Fig2 Fig5_Fig6

FIG. 1 is an illustration of a display-capable business card with piezo-strip according to an embodiment of the present disclosure.

FIG. 2 is an illustration of the display-capable business card with piezo-strip according to FIG. 1, showing the deflection of the piezo-strip and the resulting actuation of an indicator.

FIG. 5 is a photograph of a display-capable business card with piezo-strip and template over an indicator according to another embodiment of the present disclosure.

FIG. 6 is a photograph of the components of the display-capable business card with piezo-strip and template over an indicator shown in FIG. 5.

Claim 1 provides the legal statement that defines the invention:

1. A method of forming an interactive card with indicator on a substrate, comprising: forming said indicator on said substrate by way of a printed electronics process; forming a displaceable region of piezoelectric material associated with said substrate by way of a printed electronics process; forming electrical interconnections on said substrate connecting said indicator and said first region of piezoelectric material such that displacement of said first region of piezoelectric material generates a voltage therein that is provided to said indicator in order to actuate said indicator and thereby indicate the displacement of said first region of piezoelectric material, said electrical interconnections formed by way of a printed electronics process, wherein said first region of piezoelectric material is formed over a piezo-strip region of said substrate; and partially disconnecting said piezo-strip region from said substrate in order to permit displacement of said piezo-strip region independently from the remainder of said substrate.

Phil’s comments:

Piezo technology does offer quite a few opportunities for where a brief amount of power is required to trigger a device. This patent describes one use illustrated above but also extends the ideas to other applications such as switches or sensors that can indicate if vibration or bending has happened. Another application detects liquid levels by sensing where the liquid moves a series of vertical flaps on the sensor by its swirling action. I have not seen any commercial applications of this but am aware of a Swiss company that uses the piezo effect to produce a keyboard and they recently demonstrated this integrated with one of Plastic Logic’s electrophoretic displays (see here).

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