Are All LED Signs Created Equal?

Are All LED Signs Created Equal?
The answer to the question is NO!!!
There are some major differences between LED signs and what you don't know could end up hurting you...in the wallet. If you don't know what to watch out for, you will probably not be happy with your LED sign, maybe not at first, but you will end up unhappy.
The purpose of this page is to give you the tools to make an educated decision regarding purchasing a color LED sign or a monochrome LED sign.
Let's start with the basics of LED signs.
What is an LED
LED stands for Light Emitting Diode. Okay, that still doesn't answer the question, what is an LED?
Basically an LED is a small light bulb. However, it is different from incandescent light bulbs in a few key areas:
· They do not have a filament
· They are more efficient
· They have a longer life span
For those that don't know, the filament in an incandescent light bulb is where the light is produced. The filament is heated with electricity and the result is light; sort of. It would be more accurate to say 'The result is light and heat'. Why is that important? Because the object of a light bulb is to produce light which means the energy/electricity used to produce heat is wasted! Have you ever touched a light bulb that had been on for awhile? It took electricity to make the light bulb hot. When your light bulb uses a filament, there is no way around the wasted heat/electricity.
LEDs do not use filaments. That is why they are more efficient, almost all the electricity is used for making light, not heat! In other words, it doesn't cost an arm and a leg to run an LED sign because the LEDs are so efficient. The old variable message signs which used incandescent bulbs ran up massive electric bills of $500 per month OR MORE. With the advent of the LED in signs those electric bills dropped to $50 or less per month.
The LEDs used in most LED Signs are rated to last approximately 100,000 hours (about 11 years). That is a long time.
In the old days of variable message signs (which used incandescent bulbs not LEDs) operating the sign was very expensive because you had to have a service contract to have the bulbs changed every month. That alone could cost you $200 or more per month. Luckily the long life of LED signs makes those expensive service contracts a thing of the past.
LED Sign Basics
Now that you know what an LED is, there are 3 LED sign industry terms you need to understand.
· Pixel
· Pitch
· Matrix
The individual LEDs are are grouped together in what is known as a 'pixel'. The number of LEDs in each pixel varies. There could be one LED or there could be 25 LEDs in one pixel.
The major factor which determines the number of LEDs in a pixel is the 'pitch' of the pixels in the LED sign. The pitch is the distance from the center of one pixel to the center of the next pixel. The pitch determines how crisp the image will be.
If there are 2 LED signs sitting side by side and each one is the same height and width but they have different pitches, the LED sign with the smaller, tighter pitch, will have more pixels and thus a better resolution.
Selecting the right pitch when you are purchasing an LED sign may save you money as well as getting you the appropriate resolution for your particular application so make sure you read the section on choosing the right size LED sign.
The third term is 'matrix'. The matrix is made up of the number of pixel high and the number of pixels wide of an LED sign is. The matrix is what determines the physical size of the sign. If an LED sign is 24 pixels tall and 96 pixels wide, the matrix is 24x96.
In monochrome led signs and indoor led signs, the matrix determines how many lines of text you can put on the sign as well as how many characters will fit on each line. With color LED signs the matrix determines how much total space you have. A quick word or caution, having the correct height to width ratio is CRITICAL in color LED signs, you should always consult an LED sign professional for help determining the best matrix for a color LED sign.
So to sum it up...
· Groups of LEDs make Pixels
· The distance between pixels, the pitch, determines the resolution
· The number of vertical and horizontal pixels determines the matrix which determines the number of lines in the sign and the number of charcters per line.
Color or Monochrome?
The first question you need to ask yourself is do I need a color LED sign or a monochrome LED sign. Most sign salesmen will tell you that a color LED sign is more effective. I'm not one of those guys. Color can be more effective for some applications but not all applications. The only thing you can say about color LED signs that is true for every application is that it is more expensive than monochrome LED signs.
So how do you know if the additional cost is justified? Ask yourself this question: "Can my product or service be sold with a picture?".
If you sell insurance there are probably no pictures that will help you sell your product, words will sell your product.
If you sell cars you can definately sell your product with pictures.
If you answered "No" then a properly sized monochrome LED sign is probably the way to go. A properly sized monochrome LED sign is just as, if not more, effective as a color LED sign if picures and video are not helpful. You will also save a bundle in aquiring the sign.
If you answered yes, you should consider a color LED sign. They do cost more but if images can help you sell, the additional cost might be justified. Talk to an LED sign professional for help determining if a color LED sign is the way to go.
How big should my LED sign be?
Properly answering this requires a careful review of the location for the sign as well as the specific application. If you talk to a sign salesperson who does not inspect your property and ask questions about your application, be very wary, they are probably more interested in making a sale than in making sure you get the right LED sign.
There are several factors that must be considered. For instance:
· Speed Limit of Traffic
· Lanes of Traffic
· Stop signs or Stop lights
· Viewing Distance
· Sign Height/Elevation
· Content
And the list goes on.
Of all the items listed above, content is the most involved. If you are getting a monochrome LED sign you need to know what you want to say AND the most effective way to say it. Then you must consider the traffic patterns. The speed limit and viewing distance will affect the the viewing time. Your towns sign ordinance can also have an impact here.
Once you have all that information (actually you need more information than that but those are the basics) you can determine your matrix (scroll back up for a review of what the matrix is).
Now you need to determine the correct pitch. A smaller/tighter pitch will make the minimum character size smaller.
So, if your LED sign will be viewed from a long distance by people in cars travelling 45mph you will need a larger character size to make sure the traffic can read it. That means you will need a larger pitch.
If your sign will be close to the traffic and the speed limit is 25mph you can use a small character size, and smaller pitch, and your message will still be readable.
Determining the matrix and the pitch is even more complicated if you are getting a color LED sign because you must carefully consider the application as well as the aspect ratio.
As a rule of thumb, with color LED signs, the smaller the matrix and the larger the pitch, the grainier the picture on the LED sign will be.
Viewing distance also plays a role in how high of a resolution you need. If the LED sign will be viewed from a long distance you do not need as much fine detail. The closer the viewer is to the LED sign, the more detail you need. You must carefully consider what kind of content you will putting on the LED sign and the viewing distance.
If all of this seems complicated and possibly a bit overwhelming, don't worry, that is what we are here for. We have a process for going over all the details of your location and application. Then, and only then, we will make a recommendation to you.
Remember, if your LED sign is to big, you wasted money. If your LED sign is to small, you wasted money. Only a properly sized LED sign will give you the most bang for your buck .
Things to watch out for when purchasing an LED sign
The true cost of an LED sign is in the number of individual LEDs in the sign. The size of the box housing the LEDs isn't really important when it comes to pricing, in fact, that box is relatively inexpensive. The circuit boards which control the LED sign aren't the key factor in pricing, like the box they are relatively inexpensive. The key factor is the number of LEDs in the sign.
If you are considering aquiring an LED sign that is 32 pixels high and 96 pixels long and you are looking at two different brands which appear to be almost identical, even the pricing is close, which LED sign is the better bargain? There is one key piece of information you need to start to answer that question: How many LEDs are in each pixel?
Remember, pixels are groups or clusters of individual LEDs. The LED sign in this example has 3072 PIXELS (32 pixels high x 96 pixels wide). If one brand has 8 LEDs in each pixel than you are getting 24,576 LEDs. If the other brand only has 4 LEDs per pixel you are getting 12,288 LEDs.
LED density is a good indicator for comparing LED display performance. Just like your car's engine, more cylinders generally mean more power. More LEDs per pixel generally mean higher brightness and better performance. A low brightness, unreadable LED display will not help you increase your sales because it's less likely your customers will notice and read what you have to say.
The answer is probably getting pretty clear. More LEDs equals more brightness, more clarity, more attention, more customers.
The number of LEDs per pixel is also important because of degradation. Generally speaking, an LED diode will lose about 20% of its initial brightness after the first 2000 hours of use (about 3 months). After that, the LED's brightness degrades very slowly until it dies at the estimated lifetime of 100,000 hours (about 11 years). When shopping for an LED sign, it is important to keep in mind that the manufacturer's claimed display brightness will drop about 20% after 2 to 3 months of operation.Ledman magic screen is specially designed so that the brightness is slowly decayed and RGB color wonderfull matched,so that the white balance is much better.
Another consideration is the viewing angle of the sign. LEDs can put out a single, narrow beam of light like a flashlight, or they can put out a wide beam across a room like a light bulb. LEDs put out about the same amount of light no matter what type they are - but the "high-beam" LEDs with a narrow angle focus more light into one small spot, whereas the "wide angle" LEDs spread their light across the horizon. So, if you were to stand in front of a sign made from "high-beam" LEDs with narrow viewing angles, you would see an extremely bright sign, as long as you stood directly in front of it, but the minute you walked away from the front of the sign, where the "high beam" is focused, you would see nothing but black.
With wide viewing angle LEDs, the image is visible in consistent brightness and uniform colors throughout the entire viewing range of the display. A quality LED sign will have 140º of viewing angle which maintains the highest color accuracy and extends reading times.
There are 3 ways to build LED signs.
The first is to solder the LEDs directly to the circuits boards AND put a plexiglass face over the LED sign face to weather proof it. There are several drawbacks to this method. First the plexiglass shield will cause glare from the sun which will make your sign harder to read during the day. Second, beacuse the LEDs are soldered to the circuit board. If one LED goes out you sign has to be turned off, opened up, and an entire board must be replaced. This will cause a quilting effect in your sign where one section is brighter then the surrounding areas.
The second, and next best method, is to solder the LEDs directly to the circuit board but seal the entire face of the sign, without a plexiglass face shield. This eliminates the sun glare problem but it still has all the other drawbacks of the first method.
The third, and best, method is to use individually sealed pixels. With this method each pixel can be removed individually without turninf off and opening the sign. This eliminates all the drawbacks of the other two methods.
Your biggest hurdle in buying an LED sign
The biggest thing to watch out for is sign sales people. I am not saying they are dishonest, most of them are very honest hard working people. Most of them also lack the experience and/or knowledge to properly size and program an LED sign. They are expert tradesmen who really know how to build and install signs but LED signs have special issues that require special expertise.
Make sure that whoever you are dealing with is an expert at properly sizing and programming LED signs.
If they do not take the time to roll up their sleeves and really dig into your application and circumstances you need to be very wary of them. An LED sign is not a one size fits all, one phone call, purchase. They require careful planning and consideration. Do yourself a favor and talk to a professional.
Talk To A Knowledgeable Expert About An LED Display Sign For Your Business Now!!!

James Chen
Sales Manager
Ledman Optoelectronic Co., Ltd.
Add.: Building 8,Block 2,Baimang Baiwangxin Industrial Zone,XiliTown,
Nanshan District, Shenzhen, P.R.China
Cell: +86-13902944520
Fax:+86-755-86137009
Email: ledtime@gmail..com
Skype: ledmanexpert

FAQ OF LED & LED DISPLAY

1.1 LED是什么
LED是英文Light Emitting Diode的首字母缩写，意思是发光二极管，是一种具有两个电极的半导体发光器件，能直接把电转化为光。
1.1.1LED的特点
体积小、节能、环保、耐震性佳、可靠性高、可塑性好、反应速度快、组件寿命长，等等。
1.1.2LED的分类
A.按发光颜色分
按发光颜色分，可分成红色、黄色、绿色（还可细分成黄绿、标准绿和纯绿）、蓝色、白色等。 B.按发光面特征分
按发光面特征分，则有圆形、椭圆形、矩形、扇形等等。
C.按直径分
按直径分为φ3mm、φ5mm、φ7mm、φ8mm、φ10mm及φ20mm等。
D.按亮度分
分普通亮度(100mcd以下)、高亮度(几百至上千mcd)、超高亮度(上万mcd)。一般亮度LED广泛应用于各种室内显示用途，高亮度LED则适合于户外显示，超高亮度则适用于其他对亮度有更高要求的场合。
E.按亮度分： 直插式和贴片式
1.1.3 LED的参数
二极管具有单向导电性，即加上正向电压时，二极管导通，有电流通过；加上反向电压时，二极管截止，没有电流通过。其主要参数有：
A.(主)波长WD(Dominant Wavelength)
二极管能发出多种不同颜色的光，每种光对应有不同的波长，所以波长是反映光的特性的一个重要参数。
例如：620nm的光为红色光，525nm的光为绿色光，470nm的光为蓝色光。下表是波长与光的对应关系。
暗紫:380-390 标准紫:390-400　 淡 紫:400-410
蓝紫:445-455 深 蓝:455-465　标准蓝:465-475　单蓝:475-495
蓝绿:495-510 标准绿:510-525 草 绿:525-535 普绿:560-570
黄绿:570-580 标准黄:580-590 橙 黄:590-595
黄橙:595-600 标准橙:600-605 橙 红:605-610
淡红:610-620 标准红:620-630 深 红:630-645
B.正向工作电压VF
在正向电压小于某一值时，电流极小，不发光。当电压超过此值后，正向电流迅速增加，发光。IF=20mA时的电压称为正向工作电压。红、黄、黄绿LED的VF值一般在1.8-2.3V，蓝、紫LED的VF值一般在3.0-3.8V。
C.亮度IV
二极管的价格与其亮度有很大关系, 一般LED生产厂商按亮度进行分级，然后分档包装入库,常用单位是mcd。LED的顺向电流越大,则亮度越高；亮度还跟视角有关系,角度越小,亮度越高。
D.最大视角
显然，偏离轴线方向时，光线强度减弱。我们称发光强度值为轴向强度值一半的方向与轴向的夹角为半视角，半视角的两倍大小的角为最大视角，也称半功率角。
1.2 三基色（三原色）
自然界中的各种颜色都可以由红色(Red)、绿色(Green)和蓝色(Blue) 用不同的比例进行组合而得到。因此，称红、绿、蓝三种颜色为三基色，也称三原色。
LED电子显示屏是由许许多多这三种不同颜色的半导体发光二极管组成的显示系统，它通过控制半导体发光二极管的显示方式，可以动态地显示文字、图形、图像、动画、视频等各种信息。
LED显示屏的画面色彩鲜艳、立体感强，静如油画，动如电影，具有很好的广告效果，广泛应用于多种公共场所。
1.3像素(Pixel)
计算机中的图像实际上是由许许多多小点组成的。因为这些小点实在是太多、太密了，所以我们的肉眼根本就感觉不到。这些小点就称为像素，也称像素点，是组成图像的最小单位。
一般计算机屏幕15”的水平方向有1024个小点，垂直方向有768个小点，即整个屏幕由1024*768个小点组成。17” -19” LCD monitor 分辨率达1280x1024
LED显示屏像素组成(Pixel Configration)
目前全彩屏比较流行的有1R1G1B,2R1G1B,2R2G12B,4R2G2B等等。
1.4 像素间距(Pixel Pitch)
显示屏各像素的中心点之间的距离，一般用mm表示。它决定了一个全彩屏的像素数量，又称为点距或点间距，常用P or PH表示。此处的P来自英文单词Pitch的首字母。
可以测得：电脑屏幕的宽度为320mm,那么，在分辨率为1024*768时，相邻两个像素点之间的距离为：320/1024（mm）=0.31（mm）
显然，点间距越小的话，近距离观赏时，图片的细腻程度越好；点间距越大的话，最佳观测距离增大。
市场上常见的有4mm,6mm、8mm、10mm、12mm or 12.5mm、16mm、18mm,20mm、23mm、25mm、28mm,31.25mm、34mm,40mm等等。
△窍门：模块外形尺寸推算
P34模块的宽度(高度)为34*8=272mm
P25模块的宽度(高度)为25*8=200mm
P20模块的宽度为20*16=320mm 高度为20*8=160mm
P16模块的宽度为16*16=256mm 高度为16*8=128mm
P12.5模块的宽度为12.5*16=200mm 高度为12.5*8=100mm
P8大模块的宽度(高度)为8*32=256mm 小模块为8*8=64mm
我们公司P12.5、P16、P20模块为长方形，宽高比为2:1，其余为正方形。
1.5 实像素( Real Pixel)与虚拟像素（Virtual Pixel）
显示单元中每一点的红、绿、蓝显示组成部分均匀分布，以配合像素的混色效果；虚显示点的表征颜色由相邻的红、绿、蓝像素混色构成。
虚拟像素的点是平均分散的，实像素的点是凝聚的。虚拟像素的发光点在灯管间，实像素的发光点在灯管上。
按2红1绿1蓝配出的灯板，如果是实像素、3×5点阵；虚拟效果将成为5×9点阵。换算关系为：单行或单列时： M=2N-1，M：虚拟点； N：实点
整体大屏的显示效果是实像素的显示效果的四倍： n是行灯管数、m是列灯管数时：
实像素显示的像素数是：m×n
虚拟像素的显示的像点是：（2n-1）×（2m-1），这样当m和n足够大时，
就约等于2n×2m,也就是4mn,所以是实像素的四倍

为什么使用虚拟象素？
1、 可以提高显示性能：在同等的灯管数量下，虚拟像素显示相当于四倍的实像素显示的效果。 2、 可以大幅降低整屏的造价：使用虚拟像素大屏可以在同等分辨率下少用四分之一的灯管，而且能达到实像素不少用灯管同等的视觉效果，现在虚拟表贴的全彩大屏的成本主要在灯管上。
3、 使用虚拟像素可以降低人观看时的疲劳感，因为在LED大屏上发光点越是均匀分布，同等面积下发光越是均匀，所以人在观看时的疲劳感就越低。虚拟像素是现在世界最先进LED显示的技术，使用虚拟像素意味着走在世界前列。
虚拟像素在显示纯红色、纯绿色和纯蓝色时与实像素显示的效果一样。因为这是只有相应的单色的灯管是亮的。所以虚拟像素屏在显示混色时有优势。但在现实中显示的纯色的内容相对要少。
1.6 像素密度(Pixel Density)
单位面积上的像素个数称为像素密度，常用每平方米上的像素个数来表示。咱们公司的各种显示屏的像素密度可以推算如下：
像素密度=1000x1000/P2(点间距)
例如P25的像素密度是：1000000/25/25=1600(dot/sqm)
或P20的像素密度是：16*8/(0.32*0.16)=2500(dot/sqm)
显然，像素密度与点距有一一对应的关系，由此可见，用点距也可以表示显示屏的像素密度。点间距越小，像素密度越大。
1.7分辨率(Resolution)
组成一幅图像的像素个数称为分辨率，如：1024*768，1280*1024，1984*1488(2952192约3M)，就反映图像精细程度的指标之一。
数码相机的一个重要参数就是分辨率。很显然，像素越多，图像越清晰、细腻，也就越逼真。
它与显卡的属性相关，目前市场上比较流行的有：
1024x768 15”monitor
1280x1024 17” to 19” monitor
1600x1200
它与控制软件一起决定显示屏的最大尺寸。（当然显卡可以定做，相对价格较高）
1.8灰度等级 (Gray Scale)
众所周知，每种颜色都有深浅之分。以绿色为例，日常生活中就有深绿色、草绿色、浅绿色的说法。就三基色而言，每种基色也有颜色的深浅之分!而且区分得更细、更具体----是用数字来表示的！
为了便于表示，将每种基色的发光亮度按强度大小划分成若干等份，如256等。划分成的等级数就称为灰度级。用于显示视频画面的显示屏，每种基色应具有256级(8bit)的灰度处理能力。
显示屏老化过程中，有时让屏上显示某种基色，其发光亮度由弱逐渐变强(颜色由浅慢慢变深)。这实际上就是在保持同一种颜色的情况下，让基色的灰度发生变化(从0变到255)，此时的灰度等级是256级。这个过程称灰度测试。
某种基色任意时刻的发光强度就称为该基色的灰度，它决定了该种基色此时的颜色深浅。颜色深浅的变化范围则称为灰度等级。
显然，灰度等级越大，颜色区分就越细，表示出的图像就越细腻、逼真！
电脑区分颜色的能力由显卡决定。显卡的设置中包含了颜色质量的设置,这个设置实际上就是调整灰度等级的大小！
1.9 换帧频率及刷新频率 换帧频率:LED显示屏画面信息更新的频率。视频的换帧频率应不小于60帧/s。
刷新频率:LED显示屏显示数据每秒钟被重复显示的次数。体育场馆用图文屏的刷新频率应不小于60Hz，全彩视频显示屏刷新频率应不小于300Hz （户内）; 不小于600Hz(户外)。

一． 显示屏系统的硬件组成：
2.1 LED(灯)
LED电子显示屏是由许许多多半导体发光二极管组成的。LED是全彩LED显示屏的最关键部件是LED器件。原因有三：第一，LED是全彩屏整机中使用数量最多的关键器件，每平方米会使用几千至几万只LED；第二，LED是决定整屏光学显示性能的主体，直接影响观众对显示屏的评价；第三，LED在显示屏整体成本中所占比例最大，从30%至70%不等。
LED的选择已经决定了整个显示屏50%以上的质量。如果未能选择好LED，显示屏的其他部件再好也无法弥补显示屏质量的缺陷。
全彩LED显示屏专用LED的品质和参数可归结为以下五大要素：
1、 失效率
由于全彩显示屏由组红、绿、蓝三种LED组成的像素点组成，任一颜色LED的失效均会影响显示屏整体视觉效果。失控像素:发光状态与控制要求的显示状态不相符的LED像素。按照SJ/T11141-2003行业标准的规定，室内屏的像素失控率应不大于万分之三，室外屏的像素失控率应不大于千分之二，且为离散分布。我们控制在万分之一以内。
2、 抗静电能力（ANTI-ESD）
ESD是代表英文ElectroStatic Discharge即"静电放电"的意思。LED是半导体器件，对静电敏感，极易引致静电失效，故抗静电能力对显示屏的寿命至关重要。一般来说，LED的人体静电模式测试失效电压不应低于2000V。我司的LED抗ESD的能力在4000V左右。
3、 衰减特性
红、绿、蓝LED均具有随着工作时间的增加而亮度衰减的特性。LED芯片的优劣、辅助物料的好坏及封装工艺水平的高低决定了LED的衰减速度。一般来说，1000小时、20毫安常温点亮试验后，红色LED的衰减应小于10%，蓝、绿色LED的衰减应小于15%。红、绿、蓝衰减的一致性对全彩LED显示屏日后的白平衡影响很大，进而影响显示屏的显示保真度。
4、亮度
LED亮度是显示屏亮度的重要决定因素。LED亮度越高，使用电流的余量越大，对节省耗电、保持LED稳定有好处。LED有不同的角度值，在芯片亮度已定的情况下，角度越小，LED则越亮，但显示屏的视角则越小。一般应选择100度的LED以保证显示屏足够的视角。针对不同点间距和不同视距的显示屏，应在亮度、角度和价格上找到一个平衡点。
在一定环境照度下，LED显示屏各基色在最高灰度级、最高亮度时的亮度。全彩屏还包括白平衡状态下的亮度。
体育场馆的亮度按照TY/T1001.1-2005行业标准的要求应符合表1的规定并可以调节 表1 显示屏的亮度 单位：cd/㎡

全彩 双色 单色

室外 ≥5000 ≥4000 ≥1000

室内 ≥1000 ≥300 ≥120

5、 一致性
全彩显示屏是由无数个红、绿、蓝LED组成的像素拼成的，每种颜色LED的亮度、波长的一致性决定了整个显示屏的亮度一致性、白平衡一致性、色度一致性。一般来说，显示屏厂家要求器件供应商提供5nm的波长范围及1：1.3的亮度范围的LED，这些指标可由器件供应商通过分光分色机进行分级达到。电压的一致性一般不做要求。
由于LED是有角度的，故全彩LED显示屏同样具有角度方向性，即在不同角度观看时，其亮度是会递增或递减的。这样，红、绿、蓝三种颜色LED的角度一致性将严重影响不同角度白平衡的一致性，直接影响显示屏视频颜色的保真度。要做到红、绿、蓝三种LED在不同角度时亮度变化的匹配一致性，需要在封装透镜设计、原物料选择上严格进行科学设计，这取决于封装供应商的技术水平。法向方向白平衡再好的显示屏，如果LED的角度一致性不好，整屏不同角度的白平衡效果将是糟糕的。LED器件的角度一致性特性可用LED角度综合测试仪测出，对于中、高档显示屏尤为重要。
2.2 模块
模块由LED、灯板、驱动板和塑料外壳等组成，是组装LED显示屏的基本单位。根据点间距的不同，模块多种多样。如 P6、P8、P10、P12.5、P16、P20、P23、P25、P31.25、P34、P37、P40等。

2.3 箱体
为便于显示屏的安装、运行和维护，LED模块以箱体的形式进行组合。每个箱体可以理解为一个小小的显示屏。箱体的尺寸可以根据用户的需要灵活变通。箱体中所含的模块数量也根据用户的需要而定，常见的是4块长、6块高。
箱体内除含LED模块外，还有传送信号的数据排线和为模组供电的开关电源。
箱体内还常常装有接收卡。

外壳防护等级 LED显示屏的外壳防护等级应满足GB4208中的规定。室内屏屏体不低于IP20，室外屏屏体不低于IP33。
防护等级的介绍：IPXX－－第一个X表示防尘等级;第二个X表示防水等级
防尘等级：
0：没有保护
1：防止大的固体侵入
2：防止中等大小的固体侵入
3：防止小固体进入
4：防止物体大于1mm的固体进入
5：防止有害的粉尘堆积
6：完全防止粉尘进入

防水等级 0：没有保护
1：水滴滴入到外壳无影响
2：但外壳倾斜到15度时，水滴滴入到外壳无影响
3：水或雨水从60度角落到外壳上无影响
4：液体由任何方向泼到外壳没有伤害影响
5：用水冲洗无任何伤害
6：可用于船舱内的环境
7：可于短时间内浸水(1min)
8：于一定压力下长时间浸水
例如：IP65表示产品可以完全防止粉尘进入及可用水冲洗无任何伤害。

2.4 显示屏
标准的LED显示屏往往是由多个箱体组成的，分成n行m列。
这些箱体往往是大小完全相同的。少数情况下，也有例外：箱体的高度相同，宽度不同。
当然，也有只由一个箱体组成的显示屏。
2.5 控制系统
要让LED显示屏正常地工作，还需要专门的LED控制和播放软件。通过此种软件，将文字、图像和视频信号送到LED显示屏上显示出来。

DOES IT HELPS?

JAMES CHEN

KNOW-HOW OF LED SCREEN PROJECT

· 考虑用户场地所能允许的屏体面积的因素有哪些？

（1） 有效视距与实际场地尺寸的关系；
（2） 像素尺寸与分辩率；
（3） 单元为基数的面积估计；
（4） 屏体机械安装及维护操作空间；
（5） 屏体倾角对距离的影响。

· 用户需要的播放效果有哪些？

（1） 文字显示：视其文字尺寸及分辩需求而定；
（2） 普通视频显示：320×240 点阵；
（3） 数字标准DVD 显示：≥640×480 点阵；
（4） 完整计算机视频：≥800×600 点阵；

· 环境亮度对于屏体有哪些亮度要求？

一般亮度要求如下：
（1） 室内：>800CD/M2
（2） 半室内：>2000CD/M2
（3） 户外（坐南朝北）：>4000CD/M2
（4） 户外（坐北朝南）：>8000CD/M2

· 红绿蓝在白色构成方面有什么样的亮度要求？

红、绿、蓝在白色的成色方面贡献是不一样的。其根本原因是由于人类眼睛的视网
膜对于不同波长的光感觉不同而造成的。经过大量的实验检验得到以下大约比例，供参考设计：
简单红绿蓝亮度比为：3：6：1
精确红绿蓝亮度比为：3.0：5.9：1.1

· 为什么高档全彩显示屏要用纯绿管？

在实际LED 显示屏生产时，应选择发光效率高而又能获得显色丰富鲜艳的三基色
LED 灯管，以使在色度图中的色三角形面积尽可能在且靠近舌形谱色曲线，来满足丰富的彩色和发出足够的亮度而舌形曲线顶尖为515nm 波长光，所以高档LED 显示屏选用波长接近于515nm 的纯绿色光LED 管，例如选用520nm、525nm 或530nm 波长光的LED 灯管。

· 在明确亮度及点密度的要求条件下，如何计算机单管的亮度？

计算方法如下：（以两红、一绿、一蓝为例）
红色LED 灯亮度：亮度（CD）/M2÷点数/M2×0.3÷2
绿色LED 灯亮度：亮度（CD）/M2÷点数/M2×0.6
蓝色LED 灯亮度：亮度（CD）/M2÷点数/M2×0.1
例如：每平米2500 点密度，2R1G1B，每平米亮度要求为5000 CD/M2，则：
红色LED 灯亮度为：5000÷2500×0.3÷2=0.3
绿色LED 灯亮度为：5000÷2500×0.6÷2=1.2
蓝色LED 灯亮度为：5000÷2500×0.1=0.2
每像素点的亮度为：0.3×2+1.2+0.2=2.0 CD

· 为什么选用DVI 显示接口标准？

（1） DVI 显示卡接口是符合计算机国际标准的显示接口；
（2） 无需打开机箱，即可方便安装；
（3） 显存高，动态画面显示能力强；
（4） 软硬件兼容能力强；
（5） 支持所有操作系统及应用软件，显示灵活方便；
（6） 大批量生产，成本低，维护方便。

· 显示屏能不能用笔记本控制，为什么？

不能。笔记本电脑的显卡是内置的，无法实现与控制系统的连接，目前京东方有一款笔记本现在带DVI接口，可以实现笔记本控制。

· 全彩屏使用日亚管与使用国产管除价格外有哪些区别？

（1）管芯：日亚公司自主生产管芯，国产管一般使用美国或台湾公司的管芯；
（2）封装：日亚公司自主封装，国内无生产工厂，国产管封装厂家较多；
（3）一致性：日亚管同批管芯波长相差较小，一致性好，国产管一致性相对较差；
（4）使用寿命：日亚管使用寿命相对较长，国产管衰减比较严重；

· 室内模块全彩屏与贴片全彩屏有什么区别？

（1）发光部分：模块全彩屏的显示模块一般为黄绿的，纯绿的模块价格较贵；贴片全彩屏一般使用纯绿管芯；
（2）显示效果：模块全彩屏像素点视觉感觉较粗，亮度较低，容易有马赛克现象；贴片全彩屏一致性较好，亮度较高；
（3）维护：模块全彩不易维护，整块模块更换成本较高；贴片全彩易维护，可进行单灯维修更换；

· 户外屏能不能用表贴LED，为什么？

不能。户外屏安装结构要求严格，贴片LED 无法适应户外的恶劣环境；
户外屏亮度要求较高，目前贴片LED 无法达到户外屏的亮度要求。

· 户外屏的生产周期为什么比较长？

（1）原料采购：LED 灯管采购周期较长，尤其进口管芯，订货周期需4—6 周；
（2）生产工艺复杂：需经过PCB 设计、罩壳制作、灌胶、调白平衡等；
（3）结构要求严格：一般为箱体设计，需考虑防风、防雨、防雷等。

· 如何帮助用户选择适合的显示屏？

（1）显示内容的需要；
（2）可视距离、视角的确认；
（3）屏体分辩率的要求；
（4）安装环境的要求；
（5）成本的控制；

· 显示屏一般的长宽比例是多少？

图文屏：根据显示的内容确定；
视频屏：一般为4：3 或接近4：3；理想的比例为16：9。

· 一套控制系统能够控制的点数？

通讯屏A 卡：单色、双色1024×64
通讯屏B 卡：单色：896×512 双色：896×256
DVI 双色屏：1280×768
DVI 全彩屏：1024×512

· 显示屏的安装要求？

供电要求：供电接线点应在屏体尺寸之内
220V 市电供电，火线0 线接地线；
380V 市电供电，三火线一0 线接地线；
火线与0 线导线截面积相同；
10 千瓦以上显示屏应加降压启动设备。
通讯要求：通讯距离是以通讯线长为定义。
要以所安装显示屏的型号所用通讯线长度标准来安装通讯线。
通讯线禁止与电源线在同一线管内走线。
安装要求：显示屏安装左右水平，不准许后倾
吊装要加装上下调节杆
壁挂安装前要装前倾脱落钩
落地安装要加定位支撑螺栓。

· 显示屏的尺寸设计一般考虑哪些因素？

在设计屏体大小时,有三个重要的因素:
(1) 显示内容的需要；
(2) 场地空间条件；
(3) 显示屏单元模板尺寸（室内屏）或象素大小（户外屏）。

· 显示屏耗电指标与电源要求有哪些？

显示屏的耗电量分为平均耗电量和最大耗电量。平均耗电量又称工作电量，是平时实际耗电量。最大耗电量是启动时或全亮等极端情况时的耗电量，最大耗电量是交流电供电（线径，开关等）必须考虑的要素。平均耗电量一般为最大耗电量的1/3。
显示屏属大型精密电子设备，为了安全使用及可靠工作，其AC220V 电源输入端或与其相连计算机的AC220V 电源输入端必须接地。
注：计算机的AC220V 电源输入接地端已与计算机机壳相连。

· 户外屏设计及安装应考虑哪些问题？

户外屏的主要问题如下:
（1）显示屏安装在户外，经常日晒雨淋，风吹尘盖，工作环境恶劣。电子设备被淋湿或严重受潮会引起短路甚至起火，引发故障甚至火灾，造成损失；
（2）显示屏可能会受到雷电引起的强电强磁袭击；
（3） 环境温度变化极大。显示屏工作时本身就要产生一定的热量，如果环境温度过高而散热又不良，集成电路可能工作不正常，甚至被烧毁，从而使显示系统无法正常工作；
（4） 受众面宽，视距要求远、视野要求广；环境光变化大，特别是可能受到阳光直射。
针对以上特殊要求，户外显示屏必须做到：
（1） 屏体及屏体与建筑的结合部必须严格防水防漏；屏体要有良好的排水措施，一旦发生积水能顺利排放；
（2） 在显示屏及建筑物上安装避雷装置。显示屏主体和外壳保持良好接地，接地电阻小于3 欧姆，使雷电引起的大电流及时泄放；
（3） 安装通风设备降温，使屏体内部温度在-10℃～40℃之间。屏体背后上方安装轴流风机，排出热量；
（4） 选用工作温度在-40℃～80℃之间的工业级集成电路芯片，防止冬季温度过低使显示屏不能启动。；
（5） 为了保证在环境光强烈的情况下远距离可视，必须选用超高亮度发光二极管；
（6） 显示介质选用新型广视角管，视角宽阔，色彩纯正，一致协调,寿命超过10万小时。显示介质的外封装为目前最流行的带遮沿方形筒体，硅胶密封，无金属化装配；其外型精致美观，坚固耐用，具有防阳光直射、防尘、防水、防高温、防电路短路“五防”特点。

How to calculate white balance

Full color video screen

1.General requirement
— RGB FFP matching well
— RGB VA matching well
— Even colour and brightness distribution
2. The brightness ratio of RGB to achieve white balance
R : G : B = 3 : 6 : 1
3. How to convert the screen brightness into LED lamp brightness?
3.1 Pitch size
The distance between the centres of two pitches.
The most popular pitch size: 10mm, 12mm, 16mm, 20mm, 25mm….
3.2 Screen brightness
1 nit = 1cd/m2
3.3 RGB combination
The most popular combinations are: 1:1:1, 1:2:1, 2:1:1 or 2:2:1
3.4 How to calculate briefly the LED brightness if customer’s screen is 16mm pitch with 5000nit?
— The numbers of pixel in 1m2
Numbers of pixel = 1m2 / (16mm x 16mm x 10-6) = 3906 pcs/ m2
— The brightness of each pixel
Brightness of each pixel = 5000nit / 3906 pcs/ m2= 1.28 cd/pcs
— If the RGB combination is 1:1:1, the IV of RGB will be
Red = 1.28 x 30% x 1000 = 384mcd
Greed = 1.28 x 60% x 1000 = 768mcd
Blue = 1.28 x 10% x 1000 = 128mcd


DOES IT MAKE SENSE ?

ANY QUESTION,PLEASE FEEL FREE TO CONTACT WITH ME.

JAMES CHEN FROM LEDMAN

PRODUCT RANGE

LED COMPONENTS

MAGIC SCREEN LED FOR FULL COLOR DISPLAY SOLUTION

100 degree 2R1PG1B SOLUTIONLL

2508TLHR4-A02 5mm,oval,624nm,typical 550mcd

LL2508PVPG4-A02 5mm,oval,525nm,typical 1800mcd

LL2508PLBL4-A02 5mm,oval,470nm,typical 450mcd

(2R1PG1B=1SET)

100 degree 1R1PG1B SOLUTION

LL2508JQHR4-A02 5mm,oval,624nm,typical 1200mcd

LL2508PVPG4-A02 5mm,oval,525nm,typical 1800mcd

LL2508PLBL4-A02 5mm,oval,470nm,typical 450mcd

(1R1PG1B=1SET)

100 degree 2R1PG1B SOLUTION

LL2410TLHR4-A02 4mm,oval,624nm,typical 400mcd

LL2410PVPG4-A02 4mm,oval,525nm,typical 1400mcd

LL2410PLBL4-A02 4mm,oval,470nm,typical 350mcd

(2R1PG1B=1SET)

100 degree 1R1PG1B SOLUTIONLL

2410JQHR4-A02 4mm,oval,624nm,typical 1100mcd

LL2410PVPG4-A02 4mm,oval,525nm,typical 1400mcd

LL2410PLBL4-A02 4mm,oval,470nm,typical 350mcd

(1R1PG1B=1SET)

80 degree 2R1G1B SOLUTION

LL2410TLHR4-802 4mm,oval,624nm,typical 650mcd

LL2410PVSG4-802 4mm,oval,515nm,typical 1800mcd

LL2410PLBL4-802 4mm,oval,470nm,typical 400mcd

(2R1G1B=1SET)

80 degree 1R1G1B SOLUTION

LL2410JQHR4-802 4mm,oval,624nm,typical 1400mcd

LL2410PVSG4-802 4mm,oval,515nm,typical 1800mcd

LL2410PLBL4-802 4mm,oval,470nm,typical 400mcd

(1R1G1B=1SET)

1W,3W HIGH POWER LED SERIES

IN THE MEANTIME,WE HAVE SMD SOLUTIONS:

3528 SERIES,5050 SERIES, 3-IN-1 RGB ,SINGLE COLOR,SUPER BRIGHT WHITE COLOR SEIRES

OVAL LED MODULES & DISPLAYSERIES:

PITCH 10MM,12.5MM,16MM,20MM,23MM,25MM,31.25MM,34MM,40MM.....

SMD LED MOUDLES & DISPLAY SERIES:

PITCH 4MM,6MM,8MM,10MM,16MM,20MM

LES STRIPS FOR WHOLE BUILDING DECORATION:

PITCH 62.5MM 3R2G2B & 4R4G4B SOLUTION

James Chen
Sales Manager
Ledman Optoelectronic Co., Ltd.
Add.: Building 8,Block 2,Baimang Baiwangxin Industrial Zone,XiliTown,
Nanshan District, Shenzhen, P.R.China
Cell: +86-13902944520
Fax:+86-755-86137009
Email: ledtime@gmail.com
MSN: jameschen@ledman.cn
Skype: ledmanexpert

LED VIDEO SCREEN,PANTALLAS DE LED,EKRAN DIODOWY PROFESSIONAL

We, Ledman Optoelectronic Co. Ltd, is a leading LED and LED display manufacturer in China.
Our Advantages:
1. Our registered capital is more than 2 million USD.We focus on LED and LED display long term business.
2. We are located in Hi-tech Park of city center,Shenzhen,China.We are highly supported by the Bureau of Science and Technology of Shenzhen City.
3. We are TOP 500 members of bank of China.
4. We have more than 13 years technology background on LED.
5. We have patent technology on LED and LED display and honoured as Chinese "Nichia".
6. We have state-of-art automated productions line for both LED and LED display,which control the product in high quality level and reduce the man-made failure to the minimum.
7. We have CE,ETL,ROHS,ISO9001,ISO14001 certificates.Our products are made according to USA and European standards.
8. Our LED production failure rate is less than 30PPM;In our LED display,the LED failure rate is less than 5PPM.
9. We are members of Chinese Optoelectronic Association since 2004 and ISA (International Sign Association) since 2005.10.Our products have been exported world-widely and owns high reputation.
11.We keep on innovation on high quality products and technology.

Whenever you have demands on LED or LED screen,just come back to me.Ledman will offer you the best quality LED screen with good price and on time service.

James Chen
Sales Manager
Ledman Optoelectronic Co., Ltd.
Add.: Building 8,Block 2,Baimang Baiwangxin Industrial Zone,XiliTown,
Nanshan District, Shenzhen, P.R.China
Cell: +86-13902944520
Fax:+86-755-86137009
Email: ledtime@gmail.com

MSN: jameschen@ledman.cn
Skype: ledmanexpert