QLED vs OLED | Difference between QLED TV and OLED TV
This page compares QLED vs OLED and mentions difference between QLED TV and OLED TV. It mentions comparison between LED and LCD display types including OLED basics,OLED advantages and disadvantages, OLED working.
OLED | Organic Light Emitting Diode
• It is electronic device made by placing series of organic thin films between
the two conductors.
• It works based on principle of electro-luminescence which states a bright light is emitted when electrical current is being
applied.
• OLED structure consists of
Cathode, Emissive Layer, Conductive Layer, Anode and substrate.
• When voltage is applied to OLED, current flows from cathode to the anode through the organic layers.
• Due to above electrons are travelled towards emissive layer and removed from conductive layer.
• Removal of electrons from conductive layer leave out holes which need
to be filled with electrons in emissive layer.
• As a result, holes jump to emissive layer and will re-combine with electrons.
As electrons drop into holes, they release their extra energy as light.
This way, light emission takes place in the OLED device.
QLED | Quantum-dot Light Emitting Diode
Quantum dots are key elements for QLED and IGZO display technologies. Let us understand quantum dots.
What are Quantum dots ?
• They are tiny semiconductor neon scale crystals having size between 2 nm to 10 nm.
• Quantum dots emit colors based on their size and energy gap of materials used. The bigger the dimension, larger is the emitted
wavelength.
• The figure-2 depicts graph of wavelength versus fluorescence.
• Many different semiconductor materials are used to make quantum dots viz.
CdSe, CdS, PbSe, PbS, InAs, InP etc.
• Now-a-days Cadmium-free technologies are used as these technologies generate numerous color combinations
which provide better light efficiency.
• In QLED construction, thin layer of quantum dots is used in front of backlight.
• As shown in the figure-3, 6 layers are used to construct the color image viz. backlight panel,
reflector, polarising filter, TFT array, colour filter glass, quantum dots colour filter and polarising filter.
• Backlight panel: It illuminates LED from side or back of display panel. It uses special source of light
to produce visible image. This light is passed to the reflector.
• Reflector: It enhances uniformity of the illuminance distribution on target region of the image plane.
• Polarising filter: It is used to change the settings of the image passed by the reflector
in order to suppress glare or blur in image. There are various polarisers used in display technology.
• TFT array: It matches size with quantum dots in the color filter and carries out colour re-production.
It handles display of pixels on the screen.
• Colour filters with blue LED can produce billions of colours with peak brightness and better clarity.
• Polarising filter: It gives final touch to display in order to generate crystal clear image of
the screen.
• Refer advantages and disadvantages of quantum dots used in the construction of QLED.
Tabular difference between QLED vs OLED TV types
• OLEDs illuminate the LEDs themselves. Hence OLED do not need any light source.
• QLEDs do not produce light by themselves.
Instead QLEDs use backlight unit for illumination. This light is passed to the reflector as shown in order to have
uniform illumination on the image plane. Quantum dots resist moisture better and hence QLED TV will have longer life.
Moreover due to high resistance to moisture, it does not need expensive vacuum evaporation process.
• Following table mentions basic difference between QLED vs OLED TV types.
| Specifications | OLED TV (nanophotonica) | QLED TV |
|---|---|---|
| Principle | Emissive | Transmissive |
| Backlight | It emits light itself and hence does not require any backlight. | Uses LED backlight |
| Cost | High | Low |
| Power Consumption | Medium | Low |
| Display size | From 55 inches up to 88-inch OLED TVs are available | 100 inches and beyond |
| Life Span | Less | More |
| Viewing angle | Narrow or Wide (OLED with color filters has wide angle, but direct emission RGB OLED uses outcoupling structure which keeps emission purity to very narrow viewing angles). | Wide (QLED emits with equal brightness in all the directions). |
| Switching Speed | Medium | Fast |
| Weight | Thin and Light in weight | Thin and Light in weight |
| Flexibility | Flexible & portable structure | Flexible & portable structure |
This guide provides comparison between QLED vs OLED and their respective TV types.
Comparison between OLED, LED and LCD
Refer OLED vs LED vs LCD>> and LED vs LCD>> which mentions basic comparison between OLED, LED and LCD with respect to their features.
LED, LCD related links
LED vs Laser Difference between LED and LCD 2D LED vs 3D LED CoB LED Active matrix LCD vs Passive Matrix LCD DLP vs LCD
Advantages and Disadvantages of other wireless technologies
What is Difference between
difference between OFDM and OFDMA
Difference between SC-FDMA and OFDM
Difference between SISO and MIMO
Difference between TDD and FDD
FDMA vs TDMA vs CDMA
FDM vs TDM
CDMA vs GSM