NEC Display Technology explained

When looking for a suitable display many engineers download data sheets from websites on different manufacturers panels and then try to compare the common elements that effect display readability, these being Viewing Angle, Brightness and Contrast ratio.All of these elements are commonly quoted on data sheets but the criteria on how these measurements are taken can be very different.

Most specifications include details on viewing angle yet these figures cannot show the prospective user what the display looks like over the viewing angle range. One issue to look out for here is the colour shift that can take place as the user moves there line of sight through the viewing cone. This can have a dramatic effect on the view ability of a display as images can appear to change colour which may have an effect on the end users interpretation of the information on the screen.

Super Fine Technology TFT

NEC have a range of TFT panels that use Super Fine Technology (SFT) TFT technology. Here the fluids molecular make up induces the LC molecules to line up evenly and rotate horizontally when a voltage is applied. The rotation angle of the LC molecules change according to the voltage level applied which effects the amount of light transmitted. The liquid crystal molecules are always horizontal, so they appear the same size from the front. The result is that even if you change the angle at which you view the display there is little colour deviation or brightness change.

Another advantage of the SFT technology is that as LC molecules tend to rotate more smoothly in the horizontal plane, and as SFT rotates them in this plane, the result is that response time is relatively fast, regardless of the magnitude of shift in grey scale. Another key factor to consider when choosing a display is the luminance and wide colour gamut, one problem here is that normally one was possible at the expense of the other.

Conventional panel design uses colour filters within the panel construction to convert the white light from the backlight to colour the pixel. If a colour filter with high colour purity is used to improve the colour reproduction range then this will reduce the transmissivity and therefore the brightness. Conversely if you use a colour filter with high transmissivity then brightness will increase at the expense of colour rendition. However the results in this area with SA-SFT technology are impressive with high luminance/transmissivity possible whilst still maintaining 72% NTSC ratio colour Gamut.

Panels featuring SFT are:

15inch . . . NL10276BC30-17 (UA-SFT)
12.1inch . . NL8060BC31-20
10.4inch . . NL8060BC26-27, NL6448BC33-53
8.4inch . . .NL10276BC16-01, NL6448BC26-08D

ST-NLT Technology
Design Engineers who have to design the man-machine interface on products that are used in environments where the ambient light levels are very high i.e. outside applications, have always faced problems with finding a display that can be read by the user.

Some third part suppliers have introduced panels where they have removed the factory fitted backlight and fitted a high bright solution taking screen brightness’s up to fight off the effect of the high ambient conditions. These solutions have there place but the panel cost increases dramatically and to drive the brighter backlight you need more power, more power also means more heat for the designer to dissipate from the enclosure. The other problem being that the power required to run these panels negates their use in battery powered applications.

NEC has developed a technology called ST-NLT. This innovative approach boosts the efficiency of the backlight and minimises the surface reflection of the ambient light. This transmissive technology is capable of producing a high-contrast image even in bright outdoor light found on sunny days. The image has a wider colour reproduction range than reflective LCD making it an ideal choice to display bright vibrant colour in any ambient condition. Couple this with a much lower power consumption than high bright screens and at last we have a display solution for outdoor battery powered applications.

This technology has been applied across range of screen sizes including:

12.1 inch . . NL8060BC31-32
8.4inch . . . NL8060BC21-03, NL6448BC26-09C
6.5inch . . . NL6448BC20-20
5.5inch . . . NL3224BC35-22

LED Backlight Technology
NEC announces several new a-Si TFT-LCD modules incorporating newly designed LED units that achieve both long operating life and low power consumption in the backlight systems. These new products enhance NEC’s core product lineup of TFT LCD devices featuring high luminosity, long-life, low power consumption and small footprint.Recently, the demand for LCD modules equipped with white LEDs in the backlight system has risen rapidly in various
industrial fields. NEC responds on these requirements with a range of brand-new display devices. By incorporating highly luminescent, highly efficient white LEDs into the backlight system, which eliminates the need for an inverter circuit, NEC has been able to reduce power consumption in new display devices by partially more than 30% compared to modules that use
a cold-cathode fluorescent lamp (CCFL). The white LED backlight system also enables thickness and weight to be reduced bymore than 15% compared to conventional modules equipped with CCFL-based backlight systems.

Long-Life and Low-Power White LED Unit
The newly designed white LED units, optimized by NEC LCD Technologies’ proprietary optical and structural technology, out perform conventional cold-cathode fluorescent lamps (CCFL) in terms of operating life or mechanical size. They boast high reliability that is ideal for display devices in industrial equipment exposed to severe environmental conditions. In addition, all new modules reduce power consumption by more than 20 percent compared to conventional CCFL backlight systems.
Compatibility
Most of the new modules are compatible with NEC LCD Technologies’ conventional standard products of the same size in relation to outer dimensions, position of mounting holes, and screen center. Each also maintains signal compatibility with conventional products. Thus, the modules can be replaced easily without the need to change their peripheral appliances. In
accordance with NEC´s product policy, most of the LED backlight units are replaceable.

Wide operating temperature range
A wide operating temperature range guarantees operation even in extreme conditions. Moreover, the luminance of the white LED backlight performs exceptionally well under low temperatures, even from initial startup.