Paper Batteries, Blue Quantum Dots, and Other Enabling Technologies from CES 2023

Innovations from research labs aim to inspire new generations of consumer products

3 min read
Closeup of fingers pinching a thin white rectangle which has 3 black rounded rectangles inset

This paper fuel cell will soon be powering temperature and humidity trackers and smart bandages

Tekla S. Perry

CES, the huge annual conference, showcase, and deal-making venue for the international consumer electronics industry, is not just about shiny new gadgets. It’s also about what’s under the hood—or at least what researchers and developers hope will be inside a whole host of devices some day.

Here, in no particular order, are four such enabling technologies I spotted at CES 2023. It may be a year—or two, or never—before they show up in products, but all are worth watching.

Nanosys’s eyesafe blue quantum dots

A glass vial full of a glowing liquid

Adding these blue quantum dots to the traditional red and green arrays used in TV and computer displays will reduce the potential for eye damage


Nanosys, the manufacturer of quantum-dot films used in television displays from several major manufacturers, is aiming to dial down viewers’ exposure to blue light without sacrificing picture quality, by adding a blue quantum dot to its current red-and-green quantum-dot array.

Briefly, in the now-ubiquitous QLED technology, quantum dots are used to improve color quality by tuning light to precise wavelengths. These LCD-based displays typically use an array of blue LEDs as a backlight along with a quantum-dot film that converts some of that light into the red and green frequencies used to make up an RGB (red-green-blue) image, passing the blue light through unchanged.

But there is growing concern that constant exposure to blue light, due to hours of screen time every day, can cause problems over time, contributing to macular degeneration, cataracts, and other eye problems. In the shorter term, it can disrupt sleep.

Solutions to date have involved physical filters for displays, coatings for glasses, and software settings that allow changes to the white point (which makes images look a little yellow).

Nanosys says adding a blue quantum dot to the current red and green array won’t cost much (less than 10 percent more) and can reduce the harm caused by blue light without sacrificing colors or contrast. Its zinc selenide QD absorbs blue light from what is believed to be the most harmful range of wavelengths—425 to 445 nanometers—and reemits it in the 460-to-480-nm range.

The company unveiled its blue-shifting quantum dots at CES last week and says it will be ready to manufacture them in quantity before the end of the year. If and when such technology shows up on retail shelves is up to TV manufacturers.

BeFC’s paper batteries

BeFC, a spinout of the French National Center for Scientific Research (CNRS), is ready to ramp up production of paper batteries for use in sensors and other IoT devices. The company says these biofuel-based cells, which combine stored glucose with oxygen extracted from the air to generate electricity, can produce energy equivalent to a coin-cell battery. The company said that 10 to 12 products that use BeFC’s technology are in development by a variety of manufacturers. Several of those products—including a temperature and humidity tracker and a smart bandage—are due to come to market soon.

Lumus’s reflective waveguide for smart glasses

The Lumus Z-Lens reflective waveguide technology is ready to enable smaller and lighter AR glasses, the company says. This isn’t Lumus’s first attempt to become the go-to supplier of optical technology for AR wearables, but the new architecture allows for a vastly smaller image projector. And the technology that goes into smart glasses is going to have to be as small and light as possible if these devices are ever to appeal to consumers.

Typical waveguides are diffractive, that is, they break incoming light into its red, green, and blue wavelengths, then redirect and reassemble it. Lumus instead uses an array of tiny mirrors to redirect images from a projector to the eye while allowing 90 percent of light coming in from the real world to get through. The company says its reflective technology is better, preserving brightness and keeping images more precisely aligned than its diffractive competitors. Lumus also indicated that its approach allows direct bonding to lenses, making prescription AR glasses easier to produce.

The basic technology has been used in military helmets for more than a decade, but the twist announced at CES is a change in the configuration of the waveguide to expand the image in two directions, not just one.

Lumus is ready to take this technology into mass production later this year and expects to see it available in consumer products in 2025.

Ixana’s through-the-body low-power communications technology

Ixana, a spinout of Purdue University, is looking for wearable device makers to adopt its through-the-body low-power communications technology. Associate Professor Shreyas Sen and his colleagues wrote about their then work in progress in the December 2020 issue of IEEE Spectrum. They called their invention Electro-Quasistatic Human Body Communication; they’ve now tagged the commercial version Wi-R, and Sen says it’s ready for prime time.

This extremely low-power (sub-hundred microwatt) technology uses the conductive properties of the body to create a broadband communications bus. It will be perfect for use with AR glasses, Sen says, easily transmitting video from a camera in lightweight glasses to a processor worn elsewhere without draining the wearable’s battery. The company has announced that an evaluation kit is available for preorder.

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The Inner Beauty of Basic Electronics

Open Circuits showcases the surprising complexity of passive components

5 min read
A photo of a high-stability film resistor with the letters "MIS" in yellow.
All photos by Eric Schlaepfer & Windell H. Oskay

Eric Schlaepfer was trying to fix a broken piece of test equipment when he came across the cause of the problem—a troubled tantalum capacitor. The component had somehow shorted out, and he wanted to know why. So he polished it down for a look inside. He never found the source of the short, but he and his collaborator, Windell H. Oskay, discovered something even better: a breathtaking hidden world inside electronics. What followed were hours and hours of polishing, cleaning, and photography that resulted in Open Circuits: The Inner Beauty of Electronic Components (No Starch Press, 2022), an excerpt of which follows. As the authors write, everything about these components is deliberately designed to meet specific technical needs, but that design leads to “accidental beauty: the emergent aesthetics of things you were never expected to see.”

From a book that spans the wide world of electronics, what we at IEEE Spectrum found surprisingly compelling were the insides of things we don’t spend much time thinking about, passive components. Transistors, LEDs, and other semiconductors may be where the action is, but the simple physics of resistors, capacitors, and inductors have their own sort of splendor.

High-Stability Film Resistor

A photo of a high-stability film resistor with the letters "MIS" in yellow.

All photos by Eric Schlaepfer & Windell H. Oskay

This high-stability film resistor, about 4 millimeters in diameter, is made in much the same way as its inexpensive carbon-film cousin, but with exacting precision. A ceramic rod is coated with a fine layer of resistive film (thin metal, metal oxide, or carbon) and then a perfectly uniform helical groove is machined into the film.

Instead of coating the resistor with an epoxy, it’s hermetically sealed in a lustrous little glass envelope. This makes the resistor more robust, ideal for specialized cases such as precision reference instrumentation, where long-term stability of the resistor is critical. The glass envelope provides better isolation against moisture and other environmental changes than standard coatings like epoxy.

15-Turn Trimmer Potentiometer

A photo of a blue chip
A photo of a blue chip on a circuit board.

It takes 15 rotations of an adjustment screw to move a 15-turn trimmer potentiometer from one end of its resistive range to the other. Circuits that need to be adjusted with fine resolution control use this type of trimmer pot instead of the single-turn variety.

The resistive element in this trimmer is a strip of cermet—a composite of ceramic and metal—silk-screened on a white ceramic substrate. Screen-printed metal links each end of the strip to the connecting wires. It’s a flattened, linear version of the horseshoe-shaped resistive element in single-turn trimmers.

Turning the adjustment screw moves a plastic slider along a track. The wiper is a spring finger, a spring-loaded metal contact, attached to the slider. It makes contact between a metal strip and the selected point on the strip of resistive film.

Ceramic Disc Capacitor

A cutaway of a Ceramic Disc Capacitor
A photo of a Ceramic Disc Capacitor

Capacitors are fundamental electronic components that store energy in the form of static electricity. They’re used in countless ways, including for bulk energy storage, to smooth out electronic signals, and as computer memory cells. The simplest capacitor consists of two parallel metal plates with a gap between them, but capacitors can take many forms so long as there are two conductive surfaces, called electrodes, separated by an insulator.

A ceramic disc capacitor is a low-cost capacitor that is frequently found in appliances and toys. Its insulator is a ceramic disc, and its two parallel plates are extremely thin metal coatings that are evaporated or sputtered onto the disc’s outer surfaces. Connecting wires are attached using solder, and the whole assembly is dipped into a porous coating material that dries hard and protects the capacitor from damage.

Film Capacitor

An image of a cut away of a capacitor
A photo of a green capacitor.

Film capacitors are frequently found in high-quality audio equipment, such as headphone amplifiers, record players, graphic equalizers, and radio tuners. Their key feature is that the dielectric material is a plastic film, such as polyester or polypropylene.

The metal electrodes of this film capacitor are vacuum-deposited on the surfaces of long strips of plastic film. After the leads are attached, the films are rolled up and dipped into an epoxy that binds the assembly together. Then the completed assembly is dipped in a tough outer coating and marked with its value.

Other types of film capacitors are made by stacking flat layers of metallized plastic film, rather than rolling up layers of film.

Dipped Tantalum Capacitor

A photo of a cutaway of a Dipped Tantalum Capacitor

At the core of this capacitor is a porous pellet of tantalum metal. The pellet is made from tantalum powder and sintered, or compressed at a high temperature, into a dense, spongelike solid.

Just like a kitchen sponge, the resulting pellet has a high surface area per unit volume. The pellet is then anodized, creating an insulating oxide layer with an equally high surface area. This process packs a lot of capacitance into a compact device, using spongelike geometry rather than the stacked or rolled layers that most other capacitors use.

The device’s positive terminal, or anode, is connected directly to the tantalum metal. The negative terminal, or cathode, is formed by a thin layer of conductive manganese dioxide coating the pellet.

Axial Inductor

An image of a cutaway of a Axial Inductor
A photo of a collection of cut wires

Inductors are fundamental electronic components that store energy in the form of a magnetic field. They’re used, for example, in some types of power supplies to convert between voltages by alternately storing and releasing energy. This energy-efficient design helps maximize the battery life of cellphones and other portable electronics.

Inductors typically consist of a coil of insulated wire wrapped around a core of magnetic material like iron or ferrite, a ceramic filled with iron oxide. Current flowing around the core produces a magnetic field that acts as a sort of flywheel for current, smoothing out changes in the current as it flows through the inductor.

This axial inductor has a number of turns of varnished copper wire wrapped around a ferrite form and soldered to copper leads on its two ends. It has several layers of protection: a clear varnish over the windings, a light-green coating around the solder joints, and a striking green outer coating to protect the whole component and provide a surface for the colorful stripes that indicate its inductance value.

Power Supply Transformer

A photo of a collection of cut wires
A photo of a yellow element on a circuit board.

This transformer has multiple sets of windings and is used in a power supply to create multiple output AC voltages from a single AC input such as a wall outlet.

The small wires nearer the center are “high impedance” turns of magnet wire. These windings carry a higher voltage but a lower current. They’re protected by several layers of tape, a copper-foil electrostatic shield, and more tape.

The outer “low impedance” windings are made with thicker insulated wire and fewer turns. They handle a lower voltage but a higher current.

All of the windings are wrapped around a black plastic bobbin. Two pieces of ferrite ceramic are bonded together to form the magnetic core at the heart of the transformer.

This article appears in the February 2023 print issue.