The Fujifilm X-Pro1 interchangeable lens camera (MILC) has been announced and one of the lesser-known features is the shooter’s main 3-inch RGBW LCD panel. The ‘W’ stands for white, which is in addition to the standard red, green and blue subpixels normally found in LCD panels. Because of the extra white subpixel, the display is quoted as having 1,230k dots (640 x RGBW x 480).
While trying to find out more information on this new panel I stumbled upon a new LCD panel made by Sony, and trademarked as WhiteMagic. Sony began marketing this type of panel in October 2011, with a model number ACX432AKM, for digital cameras. From a first look I am pretty confident this is the LCD panel inside the Fujifilm X-Pro1.
What makes this RGBW WhiteMagic LCD panel special? Well the extra white subpixel makes the screen brighter and more efficient. This has two benefits. First off you can reduce the backlight’s power consumption by around 50% or in a different mode you can double the screen’s brightens for better viewing outdoors. For a digital camera, it means you can have better battery life while shooting indoors, or improve the camera’s usability outdoors.
In most LCD panels, white light from the screen’s backlight source (be it CFL or LED) passes through red, green and blue color filters for each subpixel, which block a large amount of light. The three resulting additive primary colors are then ‘mixed’ together to create a broad array of colors. White color is then formed by adding the red, green and blue together and having the backlight on full whack. Obviously, this is an inefficient way of going about it, since the panel first filters out large parts of the spectrum from the white backlight and then adds the result to recreate white.
In an RGBW panel, the additional white subpixel does not have any color filter over it, and an increased amount of light now passes through. Using some intelligent signal processing, each pixel can now become brighter using the same backlight as before. So, under the same power consumption you can get a brighter screen, or turn down the backlight and save power for the same brightness as in a standard RGB LCD screen.
WhiteMagic can operate in these two modes. In low power mode, brightness is 470 cd/m² with 225mW power consumption and in outdoors mode, brightness goes up to 1,000 cd/m² with 400mW consumption. Sony is hoping to also market WhiteMagic technology for mobile devices, like smartphones.
Adding a white subpixel is not something new, Nouvoyance PenTile RGBW LCD screens have existed for a while now, with the same benefits as the Sony WhiteMagic. In PenTile RGBW however, there are 2 subpixels per pixel, e.g. red and green as one pixel and then blue and white as another. To create different colors, pixels borrow colors from adjacent pixels. Because of this, there is a significant degradation in image quality as you lose color data. If I am reading Sony’s paper correctly, this is not the case with WhiteMagic. In WhiteMagic, each pixel has all four subpixels to itself, and hence the 640 x 480 resolution panel is quoted as having 1,230,000 dots.
You can read more about the Fujifilm X-Pro1 in our initial coverage here.
[Sony WhiteMagic]
