With the evolution of display technology, consumers today have come to demand lifelike picture reproduction and true, saturated colors. This has spurred the development of new (and better) color space standards, with the BT2020 protocol being the most recent standard to be developed. It’s also the color standard that comes closest to replicating the natural color space as comprehended by the human eye, covering roughly 76% of the spectra. Serving as the best pathway to achieve BT2020 compliance in industrial displays is quantum dot technology.
This article aims to establish a thorough understanding of the quantum dot technology, expanding on its fundamental principles of operation, manufacturing and implementation in the industrial display space.
Quantum Dot Technology Fundamentals
What are quantum dots?
Quantum dots get their name from their effectively zero-size dimensions; they are tiny speck of semiconductor particles having diameter of 2-10 nm. They contain 15-150 atoms. Because of their small size, they exhibit unique electrical and optical properties,which make them useful for numerous applications. One such application includes the manufacturing of industrial displays.
What specific property makes quantum dots useful for manufacturing industrial displays?
When illuminated, quantum dots emit light of highly specific frequencies. This enables manufacturers to produce displays that offer more saturated colors.
How do quantum dots emit light?
Quantum dots emit light through the phenomenon of photo luminescence.
Basically, what happens is, when quantum dots are exposed to light, the electrons present in the atoms of quantum dots, absorb the light and are excited to a higher energy band (called the conduction band). This is immediately followed by the process of relaxation, where the excited electrons fall back to the lower energy band (called the valence band). Since, there is an energy difference (called band gap) between conduction band and valence band, the falling electrons release the excess energy in form of photons. These photons are what we see as visible light. The band gap determines the wavelength of the emitted light.
Image author: Boettge
What makes quantum dots special?
The phenomenon of photo luminescence can also be observed in other semiconductors and semiconductor devices such as LEDs.
So, what exactly does make quantum dots special (or unique)?
There are two things that make quantum dots unique:
- First, quantum dots can be tailored to produce light of different wavelengths even when manufactured from the same element. This isn’t the case with other semiconductor devices where the wavelength is a function of the type of element the device has been manufactured from.
- Second, quantum dots emit light waves that have a narrow spectral bandwidth, accounting for the higher color saturation observed in images produced by quantum dot displays.
These unique characteristics of quantum dots can be explained by the highly quantized electronic states that make up the atomic structure of quantum dots.
In regular semiconductors and semiconductor devices, the energy bands are very close to each other, sometimes even overlapping. As quantum dots are smaller in size, they have fewer atoms which makes the gap betweentheir bands much wider. The electronic states are, therefore, also much more discrete and quantized for quantum dots. This facilitates production of a wider color gamut. Furthermore, by controlling the size of quantum dots, manufacturers can produce dots having different discrete energy levels which enable them to tailor these dots to emit light of required wavelengths.
Implementation of Quantum Dot Technology in Industrial Displays
Quantum dots are typically employed in LED-backlit LCD industrial displays, embedded either on top of the light-guide plate or in display glass just on top of the liquid crystal (LC) layer. It’s also worth noting that when used in industrial displays, manufacturers coat quantum dots with a semiconductor shelland modify their surface with functional ligands to protect them against the effects of photobleaching, photoluminescence blinking and auger recombination. This treatment is a vital step in the implementation of quantum dots while manufacturing industrial displays.
Industrial displays incorporated with quantum dots are known for their:
- High peak brightness
- Wider color gamut
- Excellent color accuracy
- Lower energy consumption needs
This completes our detailed discussion of quantum dot technology and its use in industrial displays. If you have any question that you would like to ask about quantum dot displays or quantum dot technology in general, feel free to reach out; REVO will be happy to answer them.
REVO is a global supplier of high-performing industrial display solutions. The company works with electronic device OEMs, contract manufacturers and independent electronic distributors, providing them with high quality displays for their specialty product design needs. For more details, please call 1-866-738-6797 or visit the company’s official website.