Black is the new black

Written by David Shapton

RedSharkBlack is the new black

A new nano material promises to transform camera, lens and display technology

Photography is about light, but more than that, it's about contrast: the difference between light and the absence of it.

Without sufficient contrast, it's impossible to reproduce a scene accurately. Fortunately our eyes are very good at making a good job out of a bad one. Most of the scenes we look at are not optimally lit.

What prompted this article is news of a new material, made out of carbon nanofibres, that somehow absorb virtually all light that hits it. This is pretty revolutionary and it, or anything like it, has the potential to transform cameras and lenses.

Apparently when you look at this material, it's not just a piece of black cloth; it actually looks like you're staring into nothing. Virtually none of the light that hits it is reflected.

And that's the important thing.

Think of some black things you've familiar with: a blackboard, a black cat, or perhaps your television when it's turned off.

Not really black

Well, none of those are really black. You can still take pictures of each of them. A blackboard still reflects some light.  A black cat is pretty black, but you can still see the fur. And a turned-off television? It's not back at all - not even slightly.

That's the problem. Even supposedly black objects still reflect a lot of light. The only way you can achieve a true black is by blocking all light sources, like in a darkroom. But then that's no good for photography either, because it's a condition that's called "Dark".

As we said before, the important thing for photographs is the contrast, or the difference, between light and dark.

Even traditional means to get a black background like black velvet cloth still aren't perfect, although they may point, in part, to the way the new material works.

Let's have a look at how "perfect black" might help us in professional imaging, starting with the display and working backwards.

Have you ever seen those massive outdoor advertising displays that show a moving picture - usually in prominent public places where the advertising "footfall" justifies the huge cost of the screens? They're incredibly bright in order to beat the strong light that's typical outside. But that's not the only reason they're bright.

When you see these screens turned off, you absolutely don't get a black rectangle. Far from it. If anything, they tend to look silver, or light grey. This is hardly going to give you great contrast. So the extreme light output of these advertising boards is as much to provide contrast relative to their own backgrounds as to combat intense incident lighting.

If you could coat the spaces between the LED pixels on these screens you'd get an enormous increase in contrast, and you'd probably be able to run them cooler and more economically as well.

Even OLEDs

The same applies to virtually any type of display screen - even OLED. While capable of showing extreme blacks in the dark, the minute you look at these screens in bright daylight, they lose some of their advantage.

Let's move back up the delivery chain to lenses and the optical space inside cameras. If you were able to coat the inside of these spaces with a zero-reflectivity material, virtually all stray light would be trapped. Any light reflected inside a lens or camera will degrade the image, and if this can be almost completely abolished, lenses would see their performance rise significantly.

Astronomers will presumably love the new material as it will make future telescopes even more sensitive (the ability to resolve distant objects is as much a function of the telescope's ability to distinguish between light and dark as its optical resolving power).

The new, hyper-black material is called Vantablack, and is made by UK company Surrey NanoSystems.

Read their press release in full after the break

Sensitive electro-optical imaging and target-acquisition systems will achieve new levels of  range and sensitivity performance thanks to a UK company’s breakthrough in developing a ‘super black’ material to be launched at the Farnborough International Air Show.

Surrey NanoSystems’ Vantablack® is revolutionary in its ability to be applied to light-weight, temperature-sensitive structures such as aluminium whilst absorbing 99.96% of incident radiation, believed to be the highest-ever recorded.

 “Vantablack is a major breakthrough by UK industry in the application of nanotechnology to optical instrumentation.  For example, it reduces stray-light, improving the ability of sensitive telescopes to see the faintest stars, and allows the use of smaller, lighter sources in space-borne black body calibration systems. Its ultra-low reflectance improves the sensitivity of terrestrial, space and air-borne instrumentation”, said Ben Jensen, Chief Technology Officer, Surrey NanoSystems.

Vantablack is the result of applying Surrey NanoSystems’ patented low-temperature carbon nanotube growth process to the UK Technology Strategy Board’s ‘Space for Growth’ programme, working alongside the National Physical Laboratory and Enersys’ ABSL Space Products division. The manufacture of `super-black` carbon nanotube-based materials has traditionally required high temperatures, preventing their direct application to sensitive electronics or materials with relatively low melting points. This, along with poor adhesion, prevented their application to critical space and air-borne instrumentation. The two year development and test programme was completed in December 2013, during which period Surrey NanoSystems successfully transferred its low-temperature manufacturing process from silicon to aluminium structures and pyroelectric sensors. As part of the programme, qualification to European Cooperation on Space Standardisation (ECSS) standards was also achieved.

Vantablack has the highest thermal conductivity and lowest mass-volume of any material that can be used in high-emissivity applications. It has virtually undetectable levels of outgassing and particle fallout, thus eliminating a key source of contamination in sensitive imaging systems. It withstands launch shock, staging and long-term vibration, and is suitable for coating internal components, such as apertures, baffles, cold shields and Micro Electro Mechanical Systems (MEMS) –type optical sensors.

 “We are now scaling up production to meet the requirements of our first customers in the defence and space sectors, and have already delivered our first orders. Our strategy includes both the provision of a sub-contract coating service from our own UK facility, and the formation of technology transfer agreements with various international partners”, said Jensen.

As a spin-off from its work in applying nanomaterials to semiconductor device fabrication, Surrey NanoSystems’ manufacturing process also enables Vantablack to be applied to flat and three-dimensional structures in precise patterns with sub-micron resolution.  Vantablack is manufactured using Surrey NanoSystems’ NanoGrowth®-Catalyst systems at the company's state of the art R&D centre in East Sussex, UK.

 

Tags: Technology

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