1、1LCD 设计指导下面的章节提供了LCD玻璃和液晶模块的基本知识,当你开始设计你自己的LCD屏或向厂商提交LCD生产申请时，是特别有用的。LCD 的玻璃基板或模块的类型设计液晶显示器的最基本步骤是决定显示器是否附加驱动电路(如果有则为液晶显示模块，否则只能为液晶显示玻璃基板)。这两种设计方案选择都有其好的一面，也有其坏的一面。当购买一个订制的 LCD 模组，其基本的电子设计工作将会被制造商做。 这显然会节省设计时间而且减少带着一个产品到需要的市场。你能从经验中得到便利，那些经验是我们在我先前的设计中，通过缩短设计周期和送出一个最佳化的产品中获得的。你需要作出最主要的决断是关于界面的类型，标注的
2、串行和平行的界面上最平常的，整合逆光类型的目的。温度范围，视角，浏览模式，对照将被考虑，但他们的决断通常是两个方面的。一块液晶显示器玻璃基板，将设计任务交给使用者，为了要完成你的设计，你需要学习很多关于 LCD 的知识。幸运地是，我们的网站提供应用程序信息和 Web 联结协助，对你可能需要的信息搜寻。购买 LCD 玻璃基板的主要原因是为了减少成本，和提供灵活的设计。该组件需要建立驱动电路的总成本通常小于一个预先建立的模块的成本，只要你对你的现有的 PC 板空间，你将不必支付额外的 PC 板在其上装载显示，并有机会获得成本效益的组装和测试。通过做一个小的预备工作，您的设计将会是一个好的模板，将允
3、许许多具有灵活性的设计师去适应设计从而改变他们的需求。LCD 的图像类型液晶显示屏可以包含字符图像，像素，图形点阵，或任何组合。图标：通过制作一个常规的 LCD，你可以把符合你生产的图像防止在玻璃板上，这些被称为“图标”。这些剪影可以采取的任何图像，你可能需要并计为一个像素或液晶网点形状。段：在 LCD 显示段构成了一个更大的字符，比如在一个七段数字字符段（显示 0-9） ，或 14 段中的一个字母数字字符（显示 0-9 及亚利桑那州）段。点阵：这些点阵，可在几乎任何规模和点计数。字符显示的例子将使用一系列的 5x7点阵创造一个字母数字字符串，或较大的 320 240，使随着变量的大小字母，数
4、字符号的影像图形阵列。液晶的类型和技术使用的技术的类型取决于你正在设计的 LCD 的具体性能。因为许多变化会做得很好的,最终的考虑是成本。所以这里是一个快速分解工艺TN: 低成本生产和视角, 平均,可怜的对比。黑颜色: 灰色。静态优先考虑,但运行良好到一个 32:1 多元化率。 LCD 玻璃的最爱。STN：生产成本和功耗中等，平均可视角度，平均对比度。染色：黑绿色或者深蓝灰2色。高复合率下工作状态良好。液晶显示模块的最爱，高端液晶显示器玻璃基板的选择。FSTN：生产成品中等偏上，电路耗能中等偏上。良好的可视角度，完美的对比度。染色：黑白色。高复合率下工作状态良好。高端液晶显示模块的最爱。阴影：
5、阴影是在显示器画面翻转的影响下形成的，并且只出现在能传送图像的显示器上。这个视觉效果是让背光定义像素打开“打开”(透明)，而“关闭”像素仍然不透明。这种配置在温和且低光照的条件下最佳。浏览模式和偏振器件观看模式控制是通过后方的一套多少所做或所不反光。我们提供的三种模式。反射:在高到中度环境光线条件下,这种类型的偏光片拥有最明亮的外观显示,以可能最高的对比度。不幸的是,它在晚上或者闪电条件是不能阅读的(试想玩游戏的孩子).半反射: (最喜欢光反射解决方案),如果你想要在一个广泛的光线条件下显示,你一般都会想要有一个反射的影像显示,它将会在明亮的阳光下,看起来很好,而且在夜里和在黄昏还会背光.在白
6、天,随着光反射的显示它将不会是不一样的显示,它将会是你能够拥有两者中可以接受的的一个,提供一个非常可以接受的外观.透射:这种显示需要一个工作的背光,除非它的光来自 LCD 后面有一个窗口的设备的光源环境，在被包含的显示器内，背光也许存在压倒高亮度环境的问题。这种类型看起来非常适合室内应用，但在应用方面不是非常好，耗电是一个问题，它需要一个强有力的背光源。请记住，这种偏光片的选择将无法运行，除非有一个积极的背光。偏振器件的同时还受温度的影响，以及被指定选择的偏光镜的质量等级啊的影响。当您已经确定您的环境温度要求，然后您需要选择偏光等级。这里是典型的选择。专业的偏振器件:使用专业的偏振镜可以在室内
7、或者大部分在室内可以应用。这些偏振器件在那些避免过高的气温、日照、和湿度的场合，不仅具有较好的使用,在大多数仪器仪表、办公室和家庭的产品,以及其他的应用场合都有使用。工业硅的偏振器件。因为恶劣的环境下,一套专为户外,极潮湿条件下被使用。我们称这些偏振器件工业等级的偏振器。视野液晶屏部分的视角定义为垂直于屏的中心的上，下，左，右角度。6:00 方向是从下往上看垂直可视平面具有最佳对比度的视角。(最流行的视角)12:00 方向是从上往下看垂直可视平面具有最佳对比度的视角。9:00 方向是从左往右看垂直可视平面具有最佳对比度的视角，(不常用)3:00 方向是从右向左看垂直可视平面具有最佳对比度的视角
8、。(不常用)请牢记在心,视角与直接驱动显示器相比不是那么重要。作为一条基本的规律：复合率越高，视角越重要。同样,如果一个带着偏极片眼镜的人来看你的显示器，你必须在评论部分说明这些，确保一个带着偏极片眼镜的观察者不会困惑。但是记住,报价问题，如果你改变了显示器的最终视角，显示器的价格不应该有太多的变化。3环境问题 温度范围LCD 工作和存储温度单位是应该着重被考虑，因为 LCD 工作温度超过或低于正常工作温度范围会使液晶屏不正常工作(当工作在非正常工作温度时)，甚至会永久损害 LCD(工作在非正常存储温度下)。液晶显示器的正常工作温度范围由液晶显示器液态晶体，偏极片，工作电压和复合率共同决定。这
9、样出，除去仔细研究这些参数的不同组合，下面有列出了一些基本规则，你可以使用这些规则规定你设计的液晶显示器的正常工作温度范围，之后在你选择恰当的液晶显示器液态晶片，偏极片以及工作电压时液晶显示器生产商可以提供帮助。以下静态值是典型的液晶显示器工作范围。液晶显示器 TN 玻璃基板/静态或低复合率时：标准温度范围：-10-+60，最大温度范围：-40-+80，专业温度范围：最低工作温度可达-55，最高工作温度为+110。液晶显示器 TN 显示模块/复用时：标准温度范围：0-+50，最大温度范围：-20-+70，专业温度范围：最低工作温度可达-40，最高工作温度为+90。液晶显示器 TN 和 FSTN
10、 显示模块/复用时：标准温度范围：0-+50，最大温度范围：-20-+70，专业温度范围：最低工作温度可达-40，最高工作温度为+80。还有一点设计者应该注意，确定液晶显示器正常工作范围时，液晶显示器液体晶片和偏极片并不是唯一的限制条件。设计时必须也考虑到可能用到的背光板和控制器 IC 的正常工作温度范围。极片并不是唯一的限制条件。设计时必须也考虑到可能用到的背光板和控制器 IC 的正常工作温度范围。液晶显示模块背光当开发一个液晶显示模块,背光灯可以被添加到光的 LCD 和有几种可供选择,背光液晶模块。要考虑的因素如照明强度，背光板使用寿命，背光板消耗的功率。下面给出现有的背光板并对他们进行简
11、单的比较。LED：LED 背光板要求在照明区域内具有一定的均匀光通量和照度，所以需要采用阵列。这项技术优先由于其各种颜色,强度、寿命长，宽温度范围内,和低电压的要求，因此广受欢迎。该种板的局限是一些配置(大尺寸)的功率消耗，以及对那些相同的照明配置。EL(艾尔)面板：这个板的背光功率很低，但它需要一个高voltag(典型的是120VAC ，400Hz)，并且EL板的使用寿命相对较短，和介质温度范围。冷阴极荧光灯泡：这个背光需要消耗很多的电，应用于较大的液晶显示器。冷阴极荧光灯泡缺点有个很短的寿命,在有限的温度范围内, 振动将减少的寿命，以及其正常工作时需要电压过高。(大于 300VAC ，30
12、-80KHz)LCD 眩光过滤器在液晶显示器前置一个防反射滤波器是可能的，这样提高了液晶显示器在恶劣照明环境下的显示效果。这个防反射滤波器直接和前面的偏极片连接起来，而且该防反射滤波器的前部表面物理和化学是相当粗糙。这个表面使得光波的传播方向没有改变，因此光波可以继续向前传播而不会反射回观察者那方。新的防反光材料，可以减少前表面反射到小于40.3或更少。外形尺寸一般而言，显示器大,价格高。最昂贵的部分的玻璃或模块LCD在大多数情况下是玻璃。制造商通常会使用主控层压板(片玻璃)这是14 “ * 16 “。我们可以产生一个单一的显示器的尺寸,或者我们可以隔断阵列成为成百上千的尺寸较小的显示器。我们
13、的策略是在这块压层板上最大限度的放置单个显示器。因此我们推荐显示器尺寸,提供给我们的客户最大玻璃的利用率。5LCD Design GuideThe following sections provide basic information on LCD glass and LCD modules, which is useful when you start designing your own LCD or submit requests to LCD manufacturers.Types of LCD Products - Glass or ModulesThe most fundamen
14、tal decision to make is whether the display will have the drive circuitry attached (module), or not (glass only). There are advantages and disadvantages to each approach.When purchasing a Custom LCD Module, the basic electronic design work will be done by the manufacturer. This obviously saves desig
15、n time and reduces the manpower needed to bring a product to market. You can benefit from the experience we have gained during our previous designs to shorten the design cycle and deliver an optimized product. The major decisions you need to make are the interface type, with standard serial or paral
16、lel interfaces being the most common, and the type of integrated backlighting desired. The temperature range, viewing angle, viewing mode, and contrast will need to be considered, but those decisions are common to both approaches.A glass only design puts the design burden on the end user. You will n
17、eed to learn a great deal about LCDs in order to complete your design. Luckily, our website provides Application Information and Web Links to assist you in the search for the information you may need.The main reasons to buy just the LCD glass are to reduce costs, and provide design flexibility. The
18、total cost of the components necessary to build the drive circuitry is typically less than the cost of a pre-built module, and as long as you have space on your existing PC board, you wont have to pay for an extra PC board on which to mount the display, and have access to cost effective assembly and
19、 test. By doing a little homework, your design will work just as well as a module, and will allow the flexibility most designers need to adapt their design to ever changing demands.Types of LCD ImagesThe LCD can contain character icons, segments, graphic dot arrays, or any combination.Icons: By maki
20、ng a custom LCD, you can place images on the glass that specifically complement your produce, these are called “Icons“. These silhouettes can take the shape of any image you may need and count as one pixel or dot on the LCD. Segments: Segments on an LCD display make up a larger character, such as a
21、segment in a seven segment numeric character (displays 0-9), or a segment in a 14 segment alpha-numeric character (displays 0-9 & A-Z).Dot Arrays: These dot arrays can be made in almost any size and dot count. Examples would be character displays that use a series of 5x7 dot arrays to create a strin
22、g of alphanumeric 6characters, or the larger 320 x 240 graphic arrays that make images along with variable size alpha-numeric characters.Types of Liquid and TechnologyThe type of technology used is determined by the specific performance requirements you set for the display that you are designing. Si
23、nce several variations will do a fine job, the ultimate consideration is cost. So here is a quick breakdown of the technologies we offer.TN: Low production and NRE costs, poor viewing angle, average contrast. Coloration: Black on Gray. Static preferred, but operates well up to a 32:1 Multiplex rate.
24、 LCD Glass favorite.STN: Medium production and NRE costs, average viewing angle, average contrast. Coloration Black on Green, or Dark Blue on Gray. Works well at high Multiplex rates. LCD Module favorite,high end LCD glass choice.FSTN: Medium high production and NRE costs. Good viewing angle, excell
25、ent contrast. Coloration Black on White. Works well at high Multiplex rates. Higher end LCD Module favorite.Negative Image: This is an effect that reverses the image on the display and is only offered with transmissive displays. The visual effect is to allow the backlight to define the pixels turned
26、 “on“ (transparent), while the “off“ pixels remain opaque. This configuration works best in moderate to low light conditions.Viewing Mode and PolarizersThe viewing mode is controlled by the rear polarizer, and how much it does or does not reflect light. We offer three modes.Reflective: This type of
27、polarizer gives the display the brightest appearance in high to moderate ambient light conditions, with the highest contrast ratio possible. Unfortunately, it will be difficult to read at night or under changing lightning conditions (think Game Boy).Transflective: (Favorite solution) If your display
28、 must be readable under a wide range of lighting conditions, you will generally want a transflective display so that it will look very good in the bright sunlight, but will also be back-lightable at twilight and at night. The tradeoff with a transflective display is that it will not look as good as
29、a reflective display during the day, and it will not look as good as a transmissive display at night. It will however enable you to have an acceptable compromise between the two, and provides a very acceptable appearance.Transmissive: This display needs to have a working backlight, unless it gets it
30、s light from being a “window“ type of device where the area behind the LCD has a light source room ambient light. Where it is in a contained display, the backlight may have a problem overpowering high ambient light. This type of display looks great for an indoor application, but is not very good in
31、applications where power consumption is a problem and it needs a strong backlight. Remember, this choice of polarizer will not operate unless there is an active backlight.The polarizers are also affected by temperature, and a quality grade must be specified when choosing a polarizer. After you have
32、determined your environmental temperature requirements, you then need to choose the polarizer grade. Here are your typical choices.7Commercial Grade Polarizers: Displays which will be indoors, or mostly indoors, can use commercial grade polarizers. These polarizers will hold up very well when used i
33、n most instrumentation, office and home products, and other applications where the products will be protected from high temperature, sunlight, and humidity.Industrial Grade Polarizers: For harsh environments, a polarizer specifically designed for outdoor, extremely humid conditions should be used. W
34、e call these polarizers industrial grade.Viewing DirectionThe viewing direction of a LCD part is defined as the angles above, below, left, and right of the point-of-view that is perpendicular to the center of the display.6:00 viewing direction has optimum contrast from below the perpendicular viewin
35、g plane (most popular).12:00 viewing direction has optimum contrast from above the perpendicular viewing plane.9:00 viewing direction has optimum contrast to the left side of the perpendicular viewing plane (uncommon).3:00 viewing direction has optimum contrast to right side of the perpendicular vie
36、wing plane (uncommon).Please keep in mind that viewing direction is less important for a direct drive display. As a general rule, the higher the multiplex rate, the more important the viewing direction becomes. Also, if your display is going to be viewed by a person wearing polarized sunglasses, you
37、 must specify this in the comment section to ensure that the display will not look blank to an observer wearing polarized sunglasses. However keep in mind that for quoting purposes, the price of the display will not change much (usually only a few cents) if you change your mind for the final viewing
38、 direction of the display.Environmental Considerations - Temperature RangeThe operating and storage temperature range of an LCD are important considerations, since operating outside of those ranges will result in a display that is not readable (outside operational range) or permanently damage the LC
39、D (outside storage range). The combination of the LCD fluid, polarizers, operational voltage, and multiplex rate determine the temperature range of the part. So instead of going through the different combinations of these parameters, here are some general guidelines you can use when specifying the t
40、emperature range of your LCD, and manufacturer can then assist you in the process of selecting the correct fluid, polarizers, and voltage for your application. These values are typical operating temperature ranges.LCD TN Glass / Static or Low Multiplex Rates: Standard Temp Range: -10C to +60C, Wide
41、Temp Range: -40C to +80C, Specialized Temp range: down to -55C, or up to +110CLCD TN Modules / Multiplexed: Standard Temp Range: -0C to +50C, Wide Temp Range: -20C to +70C, Specialized Temp range: -40C to +90CLCD STN & FSTN Modules / Multiplexed: Standard Temp Range: 0C to +50C, Wide Temp Range: -20
42、C to +70C, Specialized Temp range: -40C to +80C8Another note to remember is the LCD Glass and Polarizers are not the only limiting factors in the temperature range of the LCDs. You also need to take into consideration the temperature limitations of the backlight and controller ICs that may be presen
43、t along with the LCD.LCD Module BacklightingWhen developing an LCD Module, a backlight can be added to light the LCD and there are several options available to backlight a LCD module. The considerations in backlighting a display are the lighting intensity, life of the backlight, and the power it con
44、sumes. Here is a quick comparison of the backlights available.LED: Offered in both edge and array lit, this technology is preferred due to its variety of colors, intensity, long life (100K Hrs), wide temperature range, and low voltage requirements. The downsides are the power consumption of some con
45、figurations (large sizes), and the uniformity of the lighting for those same configurations.EL Panel: This backlight is very low power, but it requires a high voltage (120VAC 400Hz Typically) and it has a relatively short life (half intensity life 300VAC 30-80KHz).LCD Glare FilterIt is possible to p
46、ut an anti-reflective filter over the front of a display to improve viewability in harsh lighting conditions. This filter is bonded directly to the front polarizer of the display and its front surface either physically or chemically roughened. This surface re-direct the light waves so that they cont
47、inue traveling forward instead of reflecting back toward the observer. New anti-reflective materials can reduce the front surface reflections to less than 0.3% or less.Physical SizeIn general, the larger the display, the higher the price. The most expensive part of the Glass or Module LCD in most ca
48、ses is the glass. Manufacturers usually use a master laminate (Sheet of glass) which is 14“ x 16“. We can produce a single display that size, or we can partition the array into hundreds of smaller displays . Our strategy is to maximize the number of individual displays which we can get onto this laminate. We therefore recommend display sizes that give our customers maximum glass utilization.
