August 6, 2024
In our daily lives we are surrounded by a huge number of displays and a growing quantity of devices use a display as the primary Human Machine Interface (HMI). In this TOP TECH TALK, we discuss some of the latest technologies available in consumer devices and consider their suitability for incorporation into industrial products.Voice commands, and AI are revolutionizing how we interact with technology.
The traditional methods of interaction - keyboards, touchscreens, and physical buttons - are being complemented, and in some cases replaced, by more intuitive, natural ways of communication. As we step into this new era, the integration of voice command systems with advanced AI is poised to redefine the user experience across industries.
Although considered a mature technology, TN (Twisted Nematic) TFT technology was the dominant technology for years and is still worth a mention as it ‘sets the scene’ for all the other display technologies.
Figure 1, TN How does it work?
As seen in Figure 1 (Source), TN turns light on and off by controlling a twisted helix of liquid crystals. In common with all full color display technologies, each pixel has red, green and blue (RGB) sub-pixel constituents, in this case, in the form of color filters that are individually turned on and off.
In Figure 1a each sub-pixel cell is normally on when no voltage is applied. This is due to the helix arrangement of the crystals bending the light through 90 degrees. The sub-pixel cell, in this case a red one, becomes dark (b) when a voltage is applied to the transparent electrodes due to the crystals aligning with the voltage and preventing the light from passing through from the backlight.
TFT, also referred to as Active Matrix, uses a Thin Film of Transistors inside the display structure to directly control the individual pixels. TN TFT technology is relatively easy to manufacture and is low cost. The display response times are fast and there are no burn-effects or image retention. However, viewing angles are poor which is usually the biggest issue today for industrial use. Added to this, the color accuracy is generally poor due to most designs having 6-bit resolution per sub-pixel color, which gives just 64 different shades of each color - red, green and blue.
In Plane Switching displays offers a big upgrade over traditional TN, because this technology offers the benefit of very wide viewing angles and much higher color accuracy and resolution. The display response times however are slightly longer than for TN.
In terms of structure, the crystals are arranged to switch polarity within the same orientation plane as the display surface, hence the name ‘in-plane switching’.
Contrary to the action of TN; the default state of the crystals blocks the light from the backlight. When an electric current is applied, the crystals re-align with the field and light passes through.
Figure 2, The Structure of IPS LCD
Although IPS is not as power-efficient as TN, new backlight technologies make these displays extremely bright and clear. Importantly, IPS does not suffer any burn-in effects, and combined with its price performance ratio, excellent color accuracy and wide viewing angles it is close to ideal for many industrial use cases.
TOP-electronics distributes the range of IPS TFT displays. They have panel sizes from 1.3-inches to 15.6-inches, and up to 2000nits in terms of brightness (currently). These displays feature exceptional 10 000 : 1 contrast ratios, and are available at a very competitive pricing level.
Not to be confused with Micro LED, Mini LED is actually a backlighting technology which is normally used on large IPS TFT television panels. It uses an array of very small LEDs to provide (currently) several thousand local-area dimming zones on the backlight, which are controlled in concert with the display pixels.
This technique permits the turning off of the backlighting in the black zones, which helps to produce a much blacker effect thereby greatly increasing the contrast ratio.
The LEDs used for this application can be as small as 0.2 mm across, and for this reason the technology is already starting to migrate to some smaller panels where it can be used to good effect. For example, the 2021 iPad Pro uses 10 000 LEDs with 2 500 dimming zones on its 12.9-inch IPS screen.
Over time, as the LEDs become smaller and the driver silicon more readily available, we predict that this technology will also become applicable to Industrial panels as well, because it’s based on IPS and traditional LEDs, there are no burn effects associated.
Figure 3, Quantum Dot Nanocrystal Displays
With the advent of Ultra HD content there is an industry requirement for a display technology with a more accurate color range than existing traditional color filters. Quantum dots are also called nanocrystals and are actually the creation of Bell Labs and date back to the 1980’s. This technology was revived to create a new generation of color filters. Quantum dots are produced with semiconductor technology and use nanoparticle crystals in their construction. As shown in Figure 3, they work at the RGB sub-pixel level by transforming blue (or ultra violet) light sources into red or green light. The blue constituent is made up by having a transparent sub-pixel Quantum dot cell. The backlight used is therefore blue and passes through the IPS LCD to turn off and on each pixel and RGB subpixel.
Since the resulting color is actually a function of the crystal structure, the result is a significantly increased color range providing more natural color rendition and deeper saturation. This can be used in conjunction with local area dimming to provide deeper contrast ratios. There are no burn effects associated with Quantum Dot technology, and because the blue backlight energy is transformed by the quantum dots rather than filtered this produces an increase in image brightness.
We anticipate that as volumes increase and costs reduce that Quantum Dot Technology could well become accepted in the industrial space as a way to get even deeper color resolution in conjunction with IPS technology.
OLED is an abbreviation for Organic Light Emitting Diode. With this technology each pixel and RGB Sub pixel is made up of a tiny light emitting diode that emits light according to the voltage applied. Because OLED is based on an emissive technology, when no voltage is applied to the LED’s, the pixel is truly black since no light is being generated. This means there is an extremely good contrast ratio and both color accuracy and viewing angles are excellent.
OLED technology comes in two flavors with AMOLED and PMOLED, meaning active or passive matrix, which describes whether the drive transistors are placed in the structure of display or externally respectively.
Figure 4, The Structure of OLED
One of the challenges with OLED is that it can suffer from problems of burn-in, which means that if the same image is displayed for a long time the pixels that are lit up could become ‘burned’ and no longer produce as much light as the others, leaving traces on the screen which are visible when the screen images changes. There have been a lot of developments over the years to mitigate these effects and these do now work to great effect, but unfortunately burn-in is still an underlying concern for this technology, as is the higher production cost.
Recent innovations include the creation of WRGB sub pixels on some OLED panels with an additional White sub-pixel, which is used with the RGB sub-pixels to augment the brightness, However, improvements in traditional backlighting technology means that IPS TFT has the edge in terms of brightness.
Panel and tooling costs for AMOLED are comparatively high compared to TFT, and despite the many advantages, AMOLED and PMOLED displays are not so widely adopted in industrial use cases, primarily because of burn-in and lifetime concerns.
Electronic paper, also electronic ink, e-ink or electrophoretic display, are display devices that mimic the appearance of traditional ink on paper, offering high visibility in direct sunlight and ultra-low power consumption. Unlike conventional flat panel displays that emit light, an electronic paper display reflects ambient light like paper. E-paper displays are commonly found in e-readers and e-ink price tags.
Transflective displays represent a unique class of display technology designed to address the inherent trade-off between readability in various lighting conditions and energy efficiency. These displays are engineered to combine the advantages of both reflective and transmissive display modes, making them well-suited for applications such as e-readers, smartwatches, and outdoor devices.
Transflective displays are capable to function in both reflective and transmissive modes. This dual-mode operation enables the display to adapt to different lighting conditions, providing enhanced visibility in various environments. In reflective mode, transflective displays rely on ambient light to illuminate the screen. They use minimal power, making them highly energy-efficient and ideal for outdoor use.
Reflective displays offer excellent visibility in bright conditions, including direct sunlight. When light conditions are less favorable, such as indoors or in low-light environments, transflective displays can switch to transmissive mode. In this mode, they use a backlight to enhance visibility. This mode ensures that the display remains readable even when external light is insufficient.
Voice command technology has emerged as a significant trend in HMI, offering a hands-free, efficient way to control devices. This technology is particularly transformative in environments where manual operation is challenging, such as in automotive, industrial automation, and smart home systems. By using natural language processing (NLP), voice command systems can understand and execute complex instructions, making them an invaluable tool in modern HMI.
ARK-X, a leading supplier in this space, provides state-of-the-art voice command solutions designed to seamlessly integrate with various devices and applications. Their solutions are engineered to offer high accuracy in noisy environments, ensuring reliable performance even in the most demanding conditions.
The integration of AI with voice command systems takes HMI to the next level. AI-driven voice recognition systems are not only capable of understanding spoken commands but can also adapt to user preferences over time. This personalized interaction enhances user satisfaction and drives more intuitive and efficient operations.
Moreover, AI enables voice command systems to interpret contextual information, allowing machines to make informed decisions autonomously. For example, in an industrial setting, a machine equipped with AI and voice recognition can adjust its operations based on verbal feedback from the operator, improving both safety and productivity.
While voice commands and AI are transforming HMI, display technology remains a crucial component of the interface. Modern displays serve as the visual bridge between the user and the machine, providing real-time feedback and critical information.
The future of display technology is headed towards more interactive and adaptive screens, capable of responding to voice commands and AI-driven insights. For instance, a machine operator could use voice commands to bring up specific data on a screen, with the display adjusting dynamically based on the context of the operation. This level of integration between voice commands, AI, and display technology creates a more fluid and responsive HMI.
IPS looks likely to remain a core technology for industrial panels certainly for the immediate future. There are many reasons for this: The excellent price verus performance ratio plus wide viewing angles and large contrast ratios combined with the very good color rendition and lack of burn-in concerns. Added to all of this, developments in backlighting technology have steadily made the panels brighter and brighter, which has further expanded market appeal as well opening up new use cases.
Technologies such as mini-LED backlighting and quantum dots are gaining momentum in the consumer segment to further push the envelope of what IPS can do. As these technologies becomes more accepted, available and widespread, we predict they could start to find application in the industrial market segment further contributing to the dominance of IPS as the premier display technology for industrial use cases for many years going forward.
The fusion of voice command technology with AI and advanced display systems represents a significant leap forward in HMI. As these technologies continue to evolve, we can expect to see more intuitive, efficient, and user-friendly interfaces across various sectors. Our partners are at the forefront of this transformation, providing innovative voice command solutions that pave the way for the next generation of human-machine interactions. As the industry continues to innovate, the synergy between voice, AI, and display technologies will play an important role in shaping the future of HMI.
For more information on TOP's technologies, reach out to [email protected], or give us a call at +31 (0)180 - 580 492
Image Source: Elze, Tobias & Tanner, Thomas. (2012). Temporal Properties of Liquid Crystal Displays: Implications for Vision Science Experiments. PloS one. 7. e44048. 10.1371/journal.pone.0044048.
