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What is electrochromic glass and how does it work?
The OnePlus Concept One is a pretty standard concept handset, apart from one rather nifty feature. The Concept One uses electrochromic glass to hide and reveal the phone’s triple camera lenses. Taking just 0.7 seconds to turn the glass from opaque to transparent. Clearly, this is predominantly a style thing, but OnePlus also says it the glass controls the amount of light reaching the camera.
Although the Concept One won’t hit store shelves, OnePlus is looking into using the tech in future devices. So what can we expect from any future gadgets that make use of electrochromic glass and how does it all work?
What is electrochromic glass?
Electrochromic glass certainly isn’t a new technology. You may also know it as smart glass or dynamic glass. It’s been around for years and its applications range from tintable windows to skylights, and is even used to make “curtain walls.” You may have seen examples inside swanky offices, hotels, or onboard luxury airplanes.
These windows improve viewing comfort and reduce energy costs by controlling light passing through the glass. Either blocking it completely or acting as a partial filter. This allows you to keep heat in or out of predominantly glass buildings more effectively. Reducing the energy consumption required for air-conditioning and heating.
The only real drawback of electrochromic glass is price — it’s quite expensive to produce. We certainly won’t see affordable smartphones spend their limit budgets on pointless fancies like this. It’s also not as clear as standard glass, which perhaps isn’t the best fit for camera modules.
How does it work?
Electrochromic glass actually comes in either glass or plastic forms, but the key component is essentially the same with both. Two or more chemical substrates, or layers, applied to the glass control the transparency of the sheet. There are a few ways to construct these layers, such as a combination of conducting electrodes and a reflective electrochromic compound, the use of photochemicals, or electrochromic dyes controlled by current.
With the former, electrons pass between the two electrodes by reversing the voltage between them. The electrons react with the other chemicals in the layer, exciting their reflective properties and thereby turning the glass opaque. Moving the electrons out of the chemical layer returns the glass to transparency.
Electrochromic films also come in varieties not unlike LCD displays. Here, light polarizing and liquid crystal layers control the amount of light passing through the glass. Applying a voltage changes the orientation of the liquid crystal molecules, blocking light from passing through them. OnePlus is likely using this technology, as it’s the fastest type.
Despite the name, electrochromic glass only requires a very small amount of power to work. A low voltage is required only briefly to switch the glass to and from opaque. Power isn’t required to keep the glass in any particular state, keeping energy consumption to a minimum.
Electrochromic glass is a neat engineering feat that has a few useful applications. Including, perhaps, for our gadgets too. Whether or not the idea takes off in smartphones remains to be seen, but the OnePlus Concept One certainly showcases a cool new use case for smart glass.