TechTheDay

JDI or Japan Display Inc. has developed an LCD module that can mimic the kind of power efficiency associated with OLED displays. It also features the clever RGBW pixel arrangement pioneered by Sony. This advancement in LCD display technology promises significantly lower power consumption and better efficiency.

The Specs

Japan Display Inc’s new LCD is a 7-inch (17.8 cm) panel with a wide UXGA resolution or 1,200×1,920 px. This resolution translates to a pixel density of 431 pixels per inch (ppi). As mentioned, it incorporates two technologies that are aimed at lowering power consumption without sacrificing brightness. It has four subpixels that add the white (W) to the standard red, blue, and green (RGB) sub-pixel colors of typical LCDs.

The display is an LTPS IPS type that is only 1.16 mm thick. It has an NTSC ratio of 72% and a contrast ratio of 1:2,200. Surface luminance is measured at 500 cd/m² for the low power mode but it can reach a peak brightness of 1000 cd/m² in outdoor mode. Power consumption is at 690 mW with 550 mW required for the backlight and 140 mW for the panel. Viewing angle is above 160°.

WhiteMagic

WhiteMagic is a proprietary display technology developed by Sony, involving a pixel arrangement that has 4 sub-pixels in lieu of the standard 3. Instead of the traditional RGB array of sub-pixels, it includes a 4th white sub-pixel. This white sub-pixel ensures better brightness and purer whites. Most images—especially web pages—displayed on mobile screens are white or light in color. White sub-pixels allow more light to pass through, making it easier for LCD screens to produce brighter images with the same level of brightness.

This display is deemed to be a good solution for the poor visibility of displays outdoors. It can cut display power consumption by up to 50% when displaying whites and light images. This display technology debuted on the Sony Xperia P handset.

Local Dimming Backlight

According to JDI, local dimming backlight can cut WhiteMagic display power consumption further by up to 20% by analyzing and processing the images being shown on the display to appropriately adjust the backlight. Local dimming is not a newly created technology. It has been used in television displays for a number of years now. However, it has not been used on mobile display yet.

There  are different ways to implement  local dimming but it is mostly done through LED backlighting positioned on the edges. Edge-lit displays make use of multiple LEDs to illuminate the images to be displayed on screen from the sides. If the image has dominantly dark or pitch black parts concentrated in certain parts, some of the LED backlights can be turned off. In standard LCDs, the backlight continue to light up at the same level of brightness regardless of the color, contrast, or darkness of the image.

What These Mean to LCD Tech

The combination of WhiteMagic and local dimming makes it possible for LCD displays to be as efficient as OLEDs. Right now, Samsung’s OLED displays are becoming the benchmark for excellent mobile displays, having come close to the brightness levels of LCDs and having almost completely addressed the excessive saturation and color inaccuracy issues. With JDI’s WhiteMagic and local dimming, LCD display tech can once again claim superiority. WhiteMagic keeps brightness at high levels while local dimming allows the display to consume significantly lower power especially when using such device cases as the Samsung S View and LG’s QuickWindow. These two cases only show a part of the screen that should be the only part being illuminated by the backlighting. These cases work well with OLED displays but tend to make less sense when used with standard LCDs without local dimming.

JDI earlier announced the development of a WXGA 7-inch display that also applies the local dimming and WhiteMagic technologies. Except for the resolution and power consumption details, the upcoming 7-inch UXGA panel is largely similar and is guaranteed to provide a great frugal display for small tablets.

It’s a little disappointing that it’s only now that the combination of WhiteMagic and local dimming is being exploited. These two display technologies have already been in existence  for years. It’s not certain if JDI’s impressive new 7-inch displays will make it to real devices within this year but, hopefully, they do as it would be a big waste ignoring them while pursuing the unnecessary Quad HD displays for mobile phones.