From Kindles to Protecting Tanks: The Different Uses for Electrophoretic Displays

From Kindles to Protecting Tanks: The Different Uses for Electrophoretic Displays

Dr Matthew Roberts - Senior Consultant, Data Exploitation

By: Matthew Roberts
Senior Consultant, Data Exploitation

6th September 2017

Home » DSEI

Most people have heard of a Kindle or an e-reader: a device that uses an electronic paper display to allow users to read on a paper-like display in bright sunlight. What many people won’t have heard of is the other uses for this technology.

The display technology used in e-readers is usually an electrophoretic display (an ‘EPD’). EPDs work by suspending charged pigments in a fluid contained within a capsule. A voltage can be applied between electrodes on either side of the capsule in order to move the pigment. This configuration can vary, but typically a clear fluid is used with black and white pigments. The white pigments are positively charged and the black pigments are negatively charged. Varying the voltage moves the pigments to control how much of each pigment type is at the visible surface of the microcapsule. The pigments at the visible surface determine how much light is reflected and therefore how white that part of the display looks.

This is a very different approach to producing an image compared to the display technology used in TVs, laptops, and mobile phones which typically use liquid crystal displays (LCDs) or organic light-emitting diode (OLED) displays. LCD and OLED technologies alter the amount of light that is emitted. An EPD, on the other hand, is a reflective technology.

Reflective display technologies don’t need to compete with sunlight in order to be visible outdoors. This is why it is much easier to read an e-reader than a smartphone when in direct sunlight. In addition to this, EPD technology allows text and images to be displayed in such a way that doesn’t require power to maintain the image (you only need power to move the pigments).

The combination of these two properties makes for a very compelling technology for low power displays that can be used both indoors and outdoors. The applications of this technology are more varied than some people might realise. For example, EPD technology has been used in electronic supermarket price labels, indoor signs, bus timetables, bracelets, and watches. There have even been attempts to incorporate EPD display technology into phone cases and shoes.

Plextek has experimented with using the same technology to create an adaptive visual camouflage system for vehicles. We essentially use thin and flexible EPD panels to cover a vehicle with displays that are low power and visible in daylight conditions. To use an emissive display to achieve this would require huge amounts of power (and produce a lot of heat)! It would also need careful control of the brightness to blend in, whereas, the reflective nature of EPDs naturally varies in brightness as lighting conditions change.

Most EPDs create a greyscale image. We have used a colour filter array to convert black and white into shades of green and yellow. It’s a bit like putting colour overhead projector acetate over a piece of paper. The colour gamut that is produced is surprisingly flexible, ranging from light green and cream to dark green and dark brown.

This allows us to display a wide variety of camouflage schemes that are similar to those found on military vehicles. We can even display pictures and text, such as messages relating to humanitarian aid. A scheme can be changed in seconds. The versatility that this provides is very different to the traditional method of repainting a vehicle in order to change the scheme. The new capability that it provides allows schemes to be chosen that work well in one environment rather than finding a compromise for the range of environments that might be encountered.

The possibilities don’t stop there. Colour EPD technology is currently being developed, where more pigment colours are used in each capsule instead of an overlay. This will enable EPDs to cover a much richer colour gamut enabling new applications such as tablet PCs with daylight readable low power screens and large colour billboards that can be updated remotely and consume significantly less power than emissive versions.

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Most people have heard of a Kindle or an e-reader: a device that uses an electronic paper display to allow users to read on a paper-like display in bright sunlight. What many people won’t have heard of is the other uses for this technology.

The display technology used in e-readers is usually an electrophoretic display (an ‘EPD’). EPDs work by suspending charged pigments in a fluid contained within a capsule. A voltage can be applied between electrodes on either side of the capsule in order to move the pigment. This configuration can vary, but typically a clear fluid is used with black and white pigments. The white pigments are positively charged and the black pigments are negatively charged. Varying the voltage moves the pigments to control how much of each pigment type is at the visible surface of the microcapsule. The pigments at the visible surface determine how much light is reflected and therefore how white that part of the display looks.

This is a very different approach to producing an image compared to the display technology used in TVs, laptops, and mobile phones which typically use liquid crystal displays (LCDs) or organic light-emitting diode (OLED) displays. LCD and OLED technologies alter the amount of light that is emitted. An EPD, on the other hand, is a reflective technology.

Reflective display technologies don’t need to compete with sunlight in order to be visible outdoors. This is why it is much easier to read an e-reader than a smartphone when in direct sunlight. In addition to this, EPD technology allows text and images to be displayed in such a way that doesn’t require power to maintain the image (you only need power to move the pigments).

The combination of these two properties makes for a very compelling technology for low power displays that can be used both indoors and outdoors. The applications of this technology are more varied than some people might realise. For example, EPD technology has been used in electronic supermarket price labels, indoor signs, bus timetables, bracelets, and watches. There have even been attempts to incorporate EPD display technology into phone cases and shoes.

Plextek has experimented with using the same technology to create an adaptive visual camouflage system for vehicles. We essentially use thin and flexible EPD panels to cover a vehicle with displays that are low power and visible in daylight conditions. To use an emissive display to achieve this would require huge amounts of power (and produce a lot of heat)! It would also need careful control of the brightness to blend in, whereas, the reflective nature of EPDs naturally varies in brightness as lighting conditions change.

Most EPDs create a greyscale image. We have used a colour filter array to convert black and white into shades of green and yellow. It’s a bit like putting colour overhead projector acetate over a piece of paper. The colour gamut that is produced is surprisingly flexible, ranging from light green and cream to dark green and dark brown.

This allows us to display a wide variety of camouflage schemes that are similar to those found on military vehicles. We can even display pictures and text, such as messages relating to humanitarian aid. A scheme can be changed in seconds. The versatility that this provides is very different to the traditional method of repainting a vehicle in order to change the scheme. The new capability that it provides allows schemes to be chosen that work well in one environment rather than finding a compromise for the range of environments that might be encountered.

The possibilities don’t stop there. Colour EPD technology is currently being developed, where more pigment colours are used in each capsule instead of an overlay. This will enable EPDs to cover a much richer colour gamut enabling new applications such as tablet PCs with daylight readable low power screens and large colour billboards that can be updated remotely and consume significantly less power than emissive versions.

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Millimetre Wave Radar: A New Skyline for Autonomous UAS

Millimetre Wave Radar: A New Skyline for Autonomous UAS

James Henderson - Consultant, Antennas & Propagation

By: James Henderson
Consultant, Antennas & Propagation

23rd August 2017

Home » DSEI

When people talk about what technology is going to be available in the future, most 10-year-olds will imagine a world where we’re all flying around with jet packs on our backs, or being waited on by Humanoid robots. But as an engineer involved in cutting-edge technology, I like to think about a more realistic short-term answer to such a question.

One of the biggest developments over the past decade has been in enabling the autonomy of road vehicles and, whilst various technology companies are promising self-driving cars in the near future, the smaller step of driver aids has become the norm for modern cars. As with most large scale industry advances where huge sums of money are invested in their development, new technologies often open up opportunities to other industries.

This has certainly been the case with the development of cheap millimetre wave (mm-wave) devices. These have come off the back of automotive radar modules for adaptive cruise control and automatic braking assistance. But rather than looking for large vehicles in lanes on the motorway, there are many alternative applications for a mm-wave radar sensor, both for use in civil and military scenarios.

For me, the futuristic application which this enables is that Unmanned Aerial Systems (UAS) could soon be the common method for automatically delivering all manner of items. From completing takeaway meal orders to medi-kit drops for personnel on the front line – I may not be alone in having this vision but I can say that I’ve played a part in their development.

However, enabling the ability of autonomous flight for small UAS is not a trivial task. There are many difficulties involved with allowing swarms of UAS to safely navigate through the concrete jungle of an urban environment. They would need to avoid buildings, power lines, trees, and potentially other UAS on different errands.

This is especially difficult in a military context, where the environment could be hostile, complex and contested. Operations can take place day, night and in all weather conditions – this would be the case for the last mile resupply requirement (as stated in this most recent Defence and Security Accelerator competition).

For both scenarios, this requires a 3-dimensional situational awareness by detecting small objects, potentially out to hundreds of metres with a level of positional accuracy to allow a fast moving UAS to navigate through a cluttered environment. In this scenario, a low size, weight and power sensor is critical to its success, and pushing radar to operate at mm-wave frequencies could be the solution.

More often than not, radio engineers choose to go up in frequency to utilise the large amounts of available bandwidth, particularly for communication systems where users are demanding ever increasing data rates, but for this application, there’s another advantage. For high definition radar to achieve small angular resolution, the antenna needs to be large with respect to the wavelength. Therefore, increasing the frequency (which will reduce the wavelength) allows us to keep the same resolution in a smaller size.

At Plextek, we have been capitalising on the small wavelength of these mm-wave devices to design a complete radar front end on a single 10 x 10 cm circuit board. This minimises size and weight, but also system complexity, where transmit and receive antennas are inherently aligned on a flat panel.

There are many difficulties with working at higher mm-wave frequencies which primarily come from the increased precision required in every aspect of the design, as well as handling the higher loss associated with high-frequency systems. But the extra effort required is sure to be worth it if it means the Poppadoms in my Indian take away are still warm when they arrive cradled underneath an autonomous UAS. Or those vital supplies are delivered efficiently to personnel engaged in combat operations to maintain operational tempo and enable successful mission outcomes.

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When people talk about what technology is going to be available in the future, most 10-year-olds will imagine a world where we’re all flying around with jet packs on our backs, or being waited on by Humanoid robots. But as an engineer involved in cutting-edge technology, I like to think about a more realistic short-term answer to such a question.

One of the biggest developments over the past decade has been in enabling the autonomy of road vehicles and, whilst various technology companies are promising self-driving cars in the near future, the smaller step of driver aids has become the norm for modern cars. As with most large scale industry advances where huge sums of money are invested in their development, new technologies often open up opportunities to other industries.

This has certainly been the case with the development of cheap millimetre wave (mm-wave) devices. These have come off the back of automotive radar modules for adaptive cruise control and automatic braking assistance. But rather than looking for large vehicles in lanes on the motorway, there are many alternative applications for a mm-wave radar sensor, both for use in civil and military scenarios.

For me, the futuristic application which this enables is that Unmanned Aerial Systems (UAS) could soon be the common method for automatically delivering all manner of items. From completing takeaway meal orders to medi-kit drops for personnel on the front line – I may not be alone in having this vision but I can say that I’ve played a part in their development.

However, enabling the ability of autonomous flight for small UAS is not a trivial task. There are many difficulties involved with allowing swarms of UAS to safely navigate through the concrete jungle of an urban environment. They would need to avoid buildings, power lines, trees, and potentially other UAS on different errands.

This is especially difficult in a military context, where the environment could be hostile, complex and contested. Operations can take place day, night and in all weather conditions – this would be the case for the last mile resupply requirement (as stated in this most recent Defence and Security Accelerator competition).

For both scenarios, this requires a 3-dimensional situational awareness by detecting small objects, potentially out to hundreds of metres with a level of positional accuracy to allow a fast moving UAS to navigate through a cluttered environment. In this scenario, a low size, weight and power sensor is critical to its success, and pushing radar to operate at mm-wave frequencies could be the solution.

More often than not, radio engineers choose to go up in frequency to utilise the large amounts of available bandwidth, particularly for communication systems where users are demanding ever increasing data rates, but for this application, there’s another advantage. For high definition radar to achieve small angular resolution, the antenna needs to be large with respect to the wavelength. Therefore, increasing the frequency (which will reduce the wavelength) allows us to keep the same resolution in a smaller size.

At Plextek, we have been capitalising on the small wavelength of these mm-wave devices to design a complete radar front end on a single 10 x 10 cm circuit board. This minimises size and weight, but also system complexity, where transmit and receive antennas are inherently aligned on a flat panel.

There are many difficulties with working at higher mm-wave frequencies which primarily come from the increased precision required in every aspect of the design, as well as handling the higher loss associated with high-frequency systems. But the extra effort required is sure to be worth it if it means the Poppadoms in my Indian take away are still warm when they arrive cradled underneath an autonomous UAS. Or those vital supplies are delivered efficiently to personnel engaged in combat operations to maintain operational tempo and enable successful mission outcomes.

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Armor Integrity Monitoring System (AIMS)

AIMS – Body Armour Smart Sensor for the Tactical Environment

Bede O'Neill - Business Development Consultant, Defence

By: Bede O’Neill
Business Development Consultant, Defence

16th August 2017

Home » DSEI

Throughout the ages, from earliest forms of protective shields, such as leather panels, chain mail to full armoured suits – body armour has always played a crucial role in protecting the lives of combatants. Modern day armed forces personnel wear configurations that can typically include ceramic body armour plates. Ceramic plates are highly effective at minimising the effects of projectiles presenting much greater stopping power than the soft armour variants typically found in lightweight ballistic vests. Whilst ceramic armour is hard and lightweight, its inherent design is to disperse the kinetic energy and, therefore, the penetration ability of the projectile by fracturing.

As a result, it is imperative that the ceramic body armour plate is regularly checked to verify the integrity of the ceramic structure and without specialist x-ray analysis it can be very difficult to spot this damage. The consequence of x-ray analysis as an integral element of maintenance support is a prolonged inspection cycle.

To address this issue, Plextek have developed a sensor system that removes the need for regular x-ray analysis. The Armour Integrity Monitoring System (AIMS) uses a small low power inertial sensor to detect impact events sustained by the plate. The wearer of the armour can then use a smartphone with near-field communication (NFC) to interrogate the AIMS sensor to check for plate damage following an impact event.

With an estimated five year operating life, the AIMS sensor is truly a ‘fit and forget’ device that can be retrofitted to existing ceramic body armour stocks. Whilst each plate requires only one AIMS monitoring sensor, a single smartphone can be used to check the condition of an entire deployed fleet of plates.

What AIMS delivers to the user is a first line confidence test to verify that their ballistic protection is fit for use. Previously only confirmed by x-ray analysis, AIMS provides an immediate status update ensuring that personnel have the protection that they deserve.

The introduction of AIMS to an existing fleet significantly drives down the equipment whole life costs by removing the logistic and unit costs incurred when dispatching body armour back to the Original Equipment Manufacturer (OEM) for specialist x-ray analysis. As an active monitoring sensor, AIMS continues to provide an updated status of the body armour even if it has been in storage for a significant period since the last x-ray.

A truly smart sensor for the tactical environment, AIMS can be reconfigured to record multiple impact events. This information, presented on the smart phone app, can be used by medical professionals to help understand the trauma that the user has experienced. This valuable data could be used to help triage patients and diagnose the possibility and likely severity of internal injuries.

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Throughout the ages, from earliest forms of protective shields, such as leather panels, chain mail to full armoured suits – body armour has always played a crucial role in protecting the lives of combatants. Modern day armed forces personnel wear configurations that can typically include ceramic body armour plates. Ceramic plates are highly effective at minimising the effects of projectiles presenting much greater stopping power than the soft armour variants typically found in lightweight ballistic vests. Whilst ceramic armour is hard and lightweight, its inherent design is to disperse the kinetic energy and, therefore, the penetration ability of the projectile by fracturing.

As a result, it is imperative that the ceramic body armour plate is regularly checked to verify the integrity of the ceramic structure and without specialist x-ray analysis it can be very difficult to spot this damage. The consequence of x-ray analysis as an integral element of maintenance support is a prolonged inspection cycle.

To address this issue, Plextek have developed a sensor system that removes the need for regular x-ray analysis. The Armour Integrity Monitoring System (AIMS) uses a small low power inertial sensor to detect impact events sustained by the plate. The wearer of the armour can then use a smartphone with near-field communication (NFC) to interrogate the AIMS sensor to check for plate damage following an impact event.

With an estimated five year operating life, the AIMS sensor is truly a ‘fit and forget’ device that can be retrofitted to existing ceramic body armour stocks. Whilst each plate requires only one AIMS monitoring sensor, a single smartphone can be used to check the condition of an entire deployed fleet of plates.

What AIMS delivers to the user is a first line confidence test to verify that their ballistic protection is fit for use. Previously only confirmed by x-ray analysis, AIMS provides an immediate status update ensuring that personnel have the protection that they deserve.

The introduction of AIMS to an existing fleet significantly drives down the equipment whole life costs by removing the logistic and unit costs incurred when dispatching body armour back to the Original Equipment Manufacturer (OEM) for specialist x-ray analysis. As an active monitoring sensor, AIMS continues to provide an updated status of the body armour even if it has been in storage for a significant period since the last x-ray.

A truly smart sensor for the tactical environment, AIMS can be reconfigured to record multiple impact events. This information, presented on the smart phone app, can be used by medical professionals to help understand the trauma that the user has experienced. This valuable data could be used to help triage patients and diagnose the possibility and likely severity of internal injuries.

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