Ultra-high contrast dual cell TVs
August 07, 2019
When it comes to TVs, display features such as resolution, colour, contrast and refresh rates are key considerations to consumers. Specifically, buyers may now be looking for high dynamic range (HDR) TVs, which are said to deliver more colours and better contrast levels compared with standard high definition (HD) sets.
Up until now OLED has been perceived as the main technology providing ultra-high resolution and ultra-high contrast. This perception is now challenged by the recent emergence of a dual cell LCD technology that is expected to rival OLED in terms of colour and contrast. In July, Hisense launched its Dual Cell U9E LCD TV which, it claimed, exceeded the peak brightness, colour gamut, colour accuracy and HDR certification requirements of OLED TVs.
So how do these technologies compare?
OLED TVs have been coveted for their excellent colour gamut and high contrast. However OLED TVs come at a premium price and manufacturing costs are around three times higher than for a conventional LCD TV. OLED display production is known for its low yield and high costs associated with the expensive materials and processes used. In terms of display performance, OLED displays have lower brightness than LCDs and are also more susceptible to image burn-in particularly when driven with a high brightness static content such as user interface menus.
Display makers have been working on new technologies that can match the image quality provided by OLED displays but at a more affordable cost.
Dual cell LCDs
LCD TVs have been around for a few decades and today can be easily manufactured in very large sizes at significantly lower price. It is no surprise, then, that LCD TVs have the biggest market share. LCD has reinvented itself many times over the years, and now dual cell LCD gives this technology yet another facet.
In his blog, FlexEnable’s Strategy Director, Paul Cain, explains that in a dual cell structure “one display pixel (cell) is placed on top of a second display pixel. This is equivalent to having two pairs of curtains in your window – akin to a blackout blind. This means a simple, low-cost backlight can be used, and excellent blacks can be achieved.”
The disadvantage of this approach when built on glass is that the display becomes much thicker as four sheets of glass are required which also adds to the cost. For example Hisense U9E TV panel is ~13mm thick, which is still three to four times more than the minimum thickness an OLED TV panel can achieve (LG’s 65” 4K OLED TV is only 2.57mm thick). Priced at ~$2600 the 65” 4K U9E model is ~870 cheaper than the brand’s 65” OLED TV, but possibly still too expensive for the average consumer.
So what would be an alternative approach to making high contrast dual cell TVs that are also much thinner and lower cost?
Making ultra-high contrast dual cell LCDs on plastic
FlexEnable has developed a low-temperature manufacturing approach to making organic LCDs (OLCDs) using organic thin-film transistors (OTFT) built on ultra-thin thin plastic substrates like triacetylcellulose (TAC). This technology can be developed further for the fabrication of ultra-high contrast dual cell OLCDs, bringing additional advantages including thinness, lightness and flexibility. For example the use of 40μm TAC film allows for extremely thin modules even with two cells that can be manufactured in a simpler way (than dual cell glass LCD and OLED) at lower cost with higher optical performance.
TVs are not the only products that can benefit from dual cell OLCD. There is a demand for ever increasing contrast for automotive displays which can be met in several ways using dual cell OLCD. OLCD is not only extremely thin providing advantages in cost, viewing angle and module thickness, but it also retains the conformability and shapeability of the display required for automotive applications.
For more information on OLCD, please get in touch with us at email@example.com.