手机屏幕显示技术AMOLED和LCD对比(译)

关于屏幕显示技术的讨论集中在 QHD (译者注:Quad HD, 2560x1440 俗称的2K显示屏)显示和将来潜在4K手机和平板,AMOLED 和 LCD 两种技术之间的争斗讨论也如当初一样激烈。LCD 依靠令人印象深刻的 Oppo Find 7 和 LG G3 产品带领用户进入 QHD 时代,但是 AMOLED 的成长逐渐对 LCD 的统治产生威胁,因为最新的 Nexus 6,Moto X ,和高端的三星产品都使用了 AMOLED 技术。

关于哪种技术好,或者关于购买哪种屏幕显示技术手机的争辩一直在升温。如果你关心这两个技术,不妨往下读一读。

Display technology talk may be focused on the move over to QHD displays and a potential future full of 4K smartphones and tablets, but the battle between AMOLED and LCD designs is raging as fiercely as ever. LCD brought us into the QHD age through the impressive Oppo Find 7 and LG G3, but AMOLED is a growing threat to LCD’s dominance, as the latest Nexus 6, Moto X, and high-end Samsung devices are all packing the rival technology.

Debate still rages about which is the best and whether you should base your smartphone purchasing habits on such a technology. If you’re interested to know what all the fuss is about and how your smartphone’s display technology might be altering your viewing experience, then do read on.

It’s all in the design 设计的不同

争论的核心集中在子像素技术(sub-pixel technology)的实现的不同, 子像素技术是将数字数据转换到可视形式的一种技术。 这两种截然不同的实现方法导致了结果的轻微差异,这些差异体现在颜色的精确性,深颜色,最高亮度值和电池使用效率上面。

The heart of the debate revolves around two quite different approaches to sub-pixel technology, designed to convert digital data into a format that you can see. These two unique implementations lead to slightly different results when it comes to accurate color reproduction, deep blacks, peak brightness levels, and battery efficiency.

LCD

LCD是两种技术中的老技术,但是这意味着这项技术有足够的时间完善自己。你可以发现LCD技术被用在了很多高端手机和平板上,像 LG G3 , HTC One (M8) and Sony Xperia Z 产品线。第一款有着 QHD 显示的 Oppo Find 7 同样也是使用了LCD技术。

LCD is the older of the two display technologies, but if anything this means that the technology has had plenty of time to mature. You’ll find LCD displays in high-end smartphones and tablets, such as the LG G3, HTC One (M8) and Sony Xperia Z line-ups. The first QHD display, found in the Oppo Find 7, was also based on LCD technology.

LCD代表着液晶显示( Liquid Crystal Display ) ,虽然并没有很多这项技术的具体技术实现细节。但是,最重要的是这项技术建立在棘手的偏振光(polarized light)和颜色过滤(color filter )基础上。

LCD stands for Liquid Crystal Display, although this doesn’t really give us too much of a hint about how the technology actually works. Rather, the principle is based on polarized light, which is the tricky part, and a color filter.

颜色过滤被用于确定像素的颜色值,标准的红绿蓝三原色。这三种颜色能够混合到一起形成其他所有的颜色。偏振光被用来控制单独每个像素值的亮度。

The color filter is simply used to determine the color of the pixel, from the standard red, green, or blue base colors. These can then be mixed together in various quantities to recreate all of the colors in between. The polarized light filters are used to control the individual brightness of each colored pixel.

LCD pixel construction

Polarization filters and 和 cystal调整通光量,颜色滤波器控制可见光谱

Polarization filters and the cystal adjust how much light reaches the display’s surface, while the color filter controls the spectrum the light that is seen.

Polarization 通过使用一组滤波器,一个水平一个垂直平面来阻止光线。事实上,原始光线在不同方向都有振动, polarization 使得光线只在一个方向传播。在不同方向振动的原始光不仅能够通过水平滤波器还能通过垂直的滤波器。水平偏振光不能通过垂直的滤波器,反之亦然。通过组合垂直和水平的滤波器,或者两个相互垂直的滤波器,光线被完全遮住,这就是最原始的LCD像素的状态。

Polarization blocks light through the use of a couple of filters, one in the horizontal and one in the vertical plane. Essentially, the original light source has waves oscillating in every direction, the polarization filters cut this down to just a single direction. The original light, with waves in all directions, can pass through either a horizontal or vertical filter, albeit somewhat dimmer, as it contains the components for both axis. However, horizontal polarised light cannot pass through a vertical filter, or vice versa, as it does not contain any light in the correct plane. By combining one vertical and one horizontal filter, or any two filters at 90 degrees to each other, the light can be completely blocked, which is the default state of an LCD pixel.

LCD polarized light

两个相互垂直的偏振光滤波器能完全挡住光线, LCD 显示利用旋转液晶来使光线通过。
Two polarized filters angled at 90 degrees from each other completely block light. LCD displays use a twisted crystal to match polarity so that light can pass the second filter when desired. Source.

接下来就是液晶部分。在水平和垂直像素之间有可以加点方法关闭打开的阵列液晶。当液晶打开并且将光线转动90度的时候,意味着水平过滤过的光能够通过第二个垂直滤波器。每一个像素的水晶被一个晶体管控制并且可以在短时间内开关多次实现不同亮度的调节。现在我们能够调节每一个像素的颜色和单独控制每一个像素的亮度了。

This is where the liquid crystal part comes in. In between the horizontal and vertical pixels there is a nematic liquid crystal that can be switched “on or off” electronically. When the crystal is on it is twisted and rotates the light around 90 degrees, meaning that the horizontally filtered light can also pass through the second vertical filter. Each pixel’s crystal is controlled by a transistor and can be switched on and off multiple times each second in order to give the appearance of different brightness levels. We can now filter light into different colors and control the individual brightness of each pixel.

在所有像素后面的背光产生白光用来给每一个像素提供亮度和颜色的光源。背光也可以用来调整整体显示的亮度。
The backlight that sits behind all of the pixels produces white light that is filtered for brightness and color in each pixel. The backlight can also be used to adjust the overall brightness of the display.

可以想象,通过这种技术产生颜色的方法有点tricky,LCD 显示技术因此着可能不能产生完美颜色的缺点。 阻挡部分光通过第一层滤波器造成损失,并且可能有潜在的漏光现象。

As you can imagine, reproducing the right colors through all this technology can be a little tricky and LCD displays therefore can sometimes suffer from less than perfect color reproduction. There are compromises to be had when it comes to blocking a portion of the light through the first polarization filter and with potential leakage from the backlight bypassing the filtering stage.

AMOLED

AMOLED 相较于 LCD 是一门新的技术,他的名字给了我们一个很好的提示,提示这项技术是怎么运作。OLED是很重要的一部分。AMOLED 显示技术不使用背光和很多的像素级滤波器, AMOLED 显示技术使用成千上万独立可控的 organic-LED 。

AMOLED is a newer technology than LCD and its name also gives us a really good hint as to how it works. OLED is the really important part. Rather than a single backlight and lots of pixel filters, AMOLED displays use millions of individually controlled organic-LED light sources.

AMOLED 名字中的AM 代表 active-matrix , 它可以简单的理解成用来控制每一个LED像素的晶体管。active-matrix 通过晶体管持续不断的驱动单独的LED ,即使其他LEDs在改变状态,而另一面 passive-matrix 通过 x , y 轴数组控制,意味着必须刷新整行阵列才能改变一个像素值。

The AM part of the name stands for active-matrix, which simply refers to the switching transistor technology used to control each LED pixel. An active-matrix continues to drive an individual LED through a transistor even when other LEDs change states, while a passive-matrix is controlled through an X and Y axis array, meaning that you have to refresh either the row, column, or both just to change the state of a single pixel.

OLED structure

OLEDs 是半导体光,因此有阳极和阴极。亮度由通过部件的电流决定。
OLEDs are semiconductor light sources, which feature anodes and cathodes for electron flow. The brightness is determined by the electron current passing through the component. Source.

AMOLED 显示技术比较容易解释,但是制造并不是那么容易。AMOLED 不通过背光和一系列滤波器显示颜色,而是通过单独微小的LEDs灯,红绿蓝来产生一系列的颜色。 每一个LED像素的亮度由背部晶体中通过的电流控制,而电流又被晶体中的栅极电压决定。 OLEDs 通过在阴阳极中间的发射层发出光线,电子填补“holes”通过光子释放能量。
光线的颜色依赖发射层organic molecule的种类。 更高的电流意味着更多电子通过阴极,导致更多的“holes”被填充,更多的光子以光的形式释放。

AMOLED displays are a little easier to picture than and LCD panel, although not necessarily easier to manufacturer. Rather than a backlight and grids of filters for each color, AMOLED makes use of individual tiny colored LEDs, red, green, and blue, to create a wide range of colors. The brightness of each LED pixel is controlled by the current provided through the backplane transistor, which is adjusted via the transistor’s gate voltage. The OLEDs emits light in the emissive layer between the anode and cathode, where electrons fill “holes” and give up their energy as a photon. The color of the light depends on the type of organic molecule in the emissive layer. A higher current means more electrons passing from the cathode, which results in more holes filled and more photons given off as light.

因为没有滤波器作用到光源, AMOLED 显示技术能够比LCD提供更加精确的颜色,更广的对比度,并且能够通过调节单个像素来节省电量而不是像LCD那样保持背光常亮。 但是最高亮度下电流的峰值总是比LCD 显示技术高。 AMOLED也同样面临着这样的问题, 随着使用,organic-LED 降解,会导致烧屏或者屏幕部分颜色损失。

Due to the lack of filtering applied to the light sources, AMOLED displays can provide high accuracy colors, a wider contrast ratio than LCD, and can save battery through dimming individual pixels rather than leaving a backlight always-on. However, peak current draw for at high brightness levels is often higher than LCD displays. AMOLED also suffers from problems with organic-LED degradation over-time, which can lead to burn-in and/or color loss over parts of the screen.

还要一提的是, Super AMOLED 只是三星提出的一个概念,它指在显示层中加入了触摸数字转换器,而不是在像素层上加入单独的一层。这样的好处是光线反射更少,是的亮度的峰值有了稍微的提高,但是本质上并没有改变这项显示技术。

For the record, Super AMOLED is just Samsung’s term for an AMOLED display which has the touch digitizer built into the display rather than in a separate layer on top of the pixels. This has the added benefit of reflecting less light and allowing for a slightly higher peak brightness, but does not change the underlying display technology.

Which one is the best?

评判两种截然不同的显示技术显然是件困难的事情,因为两者都能产生非常好的显示效果。我们同样考虑到了两种显示技术中像素的准确性,两种技术都能够显示很大范围的颜色,白色,黑色的显示同样出色。

It is impossible to judge a display based solely on the type of display technology used, as both can produce excellent results. Instead, we also have to consider the accuracy and calibration of the pixels in each display, both types can range from high to poor levels of color, white, and black reproduction.

(这一段比较拗口,不翻译了)

The arrangement of pixels is a major factor that is mostly independent of the display technology type. PenTile RGBG, prevalent among AMOLED displays, “unevenly” distributes light through extra green pixels, which has had mixed reviews in the past. However, some LCD displays have adopted PenTile RGBW, with an extra white pixel, in order to allow for a higher peak brightness as the cost of some color fidelity. With investment, development, and fine-tuning over the years, some of these unorthodox pixel arrangements are showing excellent results.

sub-pixel layout
AMOLED and LCD technologies are just part of the story. RGB sub-pixel layouts and sizes also determine how well a display reproduces colors.

两种显示技术都有其优劣点。LCD引领着手机市场进入QHD时代,但是三星的galaxy note 4 有着很接近QHD的解析度。过去多年中无数多的测试显示三星高端Super AMOLED能够产生比LCD显示更精确的颜色。 Galaxy Note 4 有着目前市场上最精确的屏幕显示,但是和市场上最好的LCD显示技术比较也很难找到显著的差别。

Both display types have their own pros and cons. Resolution wise, LCD has the lead earlier this year due to its use in the first QHD smartphones. However, Samsung’s Galaxy Note 4 has closed the resolution gap. Numerous test conducted over the past few years has found that Samsung’s high-end Super AMOLED tends to reproduce colors more accurately than the best mobile LCD displays. The Galaxy Note 4 has the most accurate mobile display currently available, according to DisplayMate, although it is doubtful that the differences are hugely noticeable compared with the best LCD displays.

AMOLED 正逐渐变成市场上智能手机和平板显示的主流技术,但是LCD,在可预见的未来,依然占有一席之地。

AMOLED is becoming an increasingly popular smartphone and tablet display technology, with good reason, but LCD won’t be going anywhere in the foreseeable future.

原文链接:http://www.androidauthority.com/amoled-vs-lcd-differences-572859/

Related Articles

Quote Of The Day