The problem was that Passive Matrix" was slower to refresh and so the images were "ghosty" as they moved quickly across the screen, and video frame-rates couldn't be high or there would be lost frames. Since the controller needed to send signals down the entire matrix at one time, row by row, the entire matrix took relatively long to make a change, and by the time the bottom rows were done making the change, the top rows were falling behind the frame-rate. So then "Dual-Scan Passive Matrix" was devised, which divided up the rows of pixels into two sets, where every even row was controlled by one controller, and the odd rows by another. This allowed for much faster refresh rates and also for smoother transitions of image changes, leading to less "Ghosting".
"Active Matrix" was devised to change the state of the pixel (the angle of the crystals), between open and shut rapidly to reduce ghosting to almost negligible.
Then came LED which removed the slower LCD technology, removed the need for back-lighting, and allowed for much brighter displays, higher contrast ratios, wider viewing angles, less power consumption, and far faster refresh rates.
And yes, your description of LED Displays also being "Active Matrix" is correct. LED Displays are Active Matrix by nature, since each LED is backed by its own controlling transistor.
OLEDs are more efficient for two reasons...one, they use less power for the same number of lumens, and two, they use less power while at low light output levels. Non-Organic LED use nearly as much power at dramatically muted brightness as they do at full brightness. Since even while showing "black" LEDs AND OLEDs are actually "on" and activated (to keep the time to go from muted to bright minimized), they both use power, but OLEDs use far less power at the muted levels, so overall two displays, OLED and LED, displaying the same image, should show very different power consumption...and the OLED would be the winner for power efficiency at the same light levels.
And your observations are correct...the comparison is at the same light level outputs. Since OLEDs are able to produce more lumens, they can be "turned down" to reduce power consumption. But we as owners wanted MORE light, so we could see them in bright light, for instance...so they really are not "turned down" as they could be and would need to be to compare to LED displays in general. As a result, a present day OLED Display may consume comparable power with an image displayed, it will be markedly brighter at the same power level. On the other hand, at a rest state, or when there is a lot of dark screen areas, the OLED would consume considerably less power than a comparable LED Display.
For Pentile Displays, it wasn't so much a reduction in power as the primary purpose, as it was a reduction in the number of subpixels needed to produce a comparable resolution...which eventually results in less power consumption. Here's some great info on that technology from Wikipedia:
"PenTile Matrix" (a neologism from penta-, meaning "five" and tile) describes the geometric layout of the prototypical subpixel arrangement developed in the early 1990s. The layout consists of a quincunx comprising two red subpixels, two green subpixels, and one central blue subpixel in each unit cell. It was inspired by biomimicry of the human retinawhich has nearly equal numbers of L and M type cone cells, but significantly fewer S cones. As the S cones are primarily responsible for perceiving blue colors, which do not appreciably affect the perception of luminance, reducing the number of blue subpixels with respect to the red and green subpixels in a display does not reduce the image quality.This layout is specifically designed to work with and be dependent upon subpixel rendering that uses only one and a quarter subpixel per pixel, on average, to render an image. That is, that any given input pixel is mapped to either a red-centered logical pixel, or a green-centered logical pixel.
PenTile was invented by Candice H. Brown Elliott. The technology was licensed by the company Clairvoyante from 2000 until 2008, during which time several prototype PenTile displays were developed by a number of Asian liquid crystal display (LCD) manufacturers. In March 2008, Samsung Electronics acquired Clairvoyante’s PenTile IP assets. Samsung then funded a new company, Nouvoyance, Inc. to continue development of the PenTile technology.
PenTile RGBG layout used in AMOLED displays uses green pixels interleaved with alternating red and blue pixels. The human eye is most sensitive to green, especially for high resolution luminance information. The green subpixels are mapped to input pixels on a one to one basis. The red and blue subpixels are subsampled, reconstructing the chroma signal at a lower resolution. The luminance signal is processed using adaptive subpixel rendering filters to optimize reconstruction of high spatial frequencies from the input image, wherein the green subpixels provides the majority of the reconstruction. The red and blue subpixels are capable of reconstructing the horizontal and vertical spatial frequencies, but not the highest of the diagonal. Diagonal high spatial frequency information in the red and blue channels of the input image are transferred to the green subpixels for image reconstruction. Thus the RG-BG scheme creates a color display with one third fewer subpixels than a traditional RGB-RGB scheme but with the same measured luminance display resolution. This is similar to the Bayer filter commonly used in digital cameras.
Last edited by FoxKat; 07-26-2012 at 10:04 PM.
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Yeah true but with the announcement that the Q is gonna have a unlovkable boot loader let's pray and hope Moto comes through with our HD. No negative comments lol, I don't want anyone to ruin my hopes hahaOriginally Posted by jgmecarter
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