Which lighting application was one of the first to embrace a mass adoption of LEDs? Signage.

要提到第一个大量采用LED照明应用的要非标识标牌莫属。

Red, orange, yellow, blue, and green LED’s were the first to reach performance levels capable of providing a compelling reason for sign manufacturers to switch from traditional light sources to LED.

LED照明包括橙、黄、蓝、绿等色域，这些达到性能水平的产品，为标识制造商提供了从传统光源到LED照明的切换。

Their unique characteristics—including compact size, ease of installation, resistance to breakage and vibration, good performance in cold temperatures, reduced maintenance costs, long life, and potential for energy savings as compared to the traditional products—drove the high rate of adoption. A few years later, the steep climb in efficiency and overall performance of white LEDs allowed them to enter the mass signage market.

LED照明的特点包括具有紧凑的尺寸、易于安装、耐损坏、防振，不仅在低温下能发挥良好的性能，而且还能降低维护的成本，使用寿命的长度与传统产品相比更长更节能，尤其是白光LED，凭借它们实现的整体性能，使它们迅速在标识行业得到了发挥和应用。

Rapid Adoption

快速采纳

The high efficacy (lumens per watt) performance of white LEDs lead to their rapid adoption into signage and other early adopting mainstream applications such as refrigeration case and roadway lighting. Most of the white light technologies that were developed over the past 130 years, such as high intensity discharge (HID) lamps, have shown an initial rapid increase in efficacy and then many years of very slow improvements.

白光LED整体性能的优越性，迅速成为了发光标识采用的主流应用。过去开发的白光技术，例如高强度放电灯，其效能在初步增长快速，但是它的技术改进却非常缓慢。

Often referred to as the “hockey stick curve" due to its shape, the performance curve of white LED light technology is steep, showing an exponential increase over a very short period of time. White LEDs of today have hit lumen per watt (lm/W) levels that were unheard of only a couple years ago.

白光LED技术通常被称为“曲棍球曲线”，性能像一条陡峭的曲线，在很短的时间内呈指数增长，而今天的白光LED能达到每瓦很高的水平，这是在几年前闻所未闻的。

Some types of discrete phosphor converted white LEDs have surpassed 200 lm/W and have an estimated quantum limit of 255 lm/W with long-term research and development goals to reach 350 lm/W with new methods. The overall efficiency of the complete LED system is, however, less due to other system component losses.

有些类型的磷光体转换白光LED能达到每瓦200流明的光度，但量子的限制为每瓦255流明的光度255lm / W，经过长期研发，目标将达到每瓦350流明的光度。尽管能达到这样的光度，LED系统的总体功效还是会因为其它组件的损耗而降低。

Losses internal to the LED package, electrical, thermal, and optical losses in an LED module, and power supply losses all reduce overall LED system efficiency, but LED systems still have much higher system efficacy than traditional light sources. Additionally, unlike fluorescent or neon, the directional nature of the light from LED sources also contributes to higher overall system efficiencies due to a more efficient use of the light produced.

LED封装内部的损耗、模块中电、热、光的损耗，以及电源的损耗，都会降低LED系统的整体功效，即使这样，LED照明系统仍然比传统光源的效能要高得多。除此之外，与荧光灯或氖灯不同的是，它能有效地利用所产生的光，利用源光的定向特性也能提高它的整体功效。

But what really constitutes a good quality LED that can be effectively integrated into an LED signage module or an LED light engine for a general lighting luminaire? To start, we need some basic understanding of what a light emitting diode (LED) is and how it is manufactured. LEDs are semiconductor diode components that convert electrical current into light (photons).

但是，如何才能组合成优质的LED，集成到标识模块中呢？首先，我们需要了解一些基本的专业知识，知道什么是发光二极管，它又是如何制造，LED是如何将电流转换为光进入半导体二极管组件中。

How Does an LED emit light?

LED如何发光？

· Every LED chip consists of two semiconductor material types:

· 每个LED芯片由两种半导体材料组成：

            N-Type material—extra electrons (negative charge carriers)

N型材料 - 额外电子（负电荷载体）

            P-Type material—holes (positive charge carriers)

P型材料（正电荷载体）

· When voltage is applied, electrons combine with holes to release energy in the form of light and heat.

·施加电压时，电子与孔结合，以光和热的形式释放能量。

LEDs are grown on substrates on which layers are grown atom by atom. After various processing steps, the entire wafer is diced into individual chips. Each wafer can yield thousands of chips. Those chips are placed into a discrete LED package that can then be manufactured into a lighting module. The chip design, fabrication process, and package all contribute to and determine an LED’s performance. New advanced LED designs with improved light extraction and beam-shaping lenses have helped drive better performance.

LED在以原子的基底上形成，将整个晶片切成单独的芯片，每个晶片可以产生数千个芯片，将这些芯片放置在分立的LED中，然后就可以制成照明模块了。芯片设计、制造工艺和封装都对LED的性能有着重要的影响。此外，还有一种光束成形的透镜也是有助于提高LED的性能。

Achieving White Light

LED实现白光的方式

The light that is produced from an LED is generated in a very narrow wavelength band, meaning that the light is typically a saturated color. The semiconducting material used in an LED determines its wavelength or color of light. Because of this, there is really no such thing as an LED that by itself emits white light.

LED发出的光是在非常窄的波带中产生，这意味着光的颜色非常饱和。用于LED的半导体材料决定着波长和颜色。那么，LED是如何实现白光的呢？

White light from LEDs is most widely achieved through the use of a blue LED chip combined with a phosphor, similar to the way a fluorescent lamp operates. The phosphor layer absorbs a portion of the blue light and emits light at longer wavelengths. The phosphor concentration defines how much of the blue light is converted. The phosphor can be applied over the LED die, such as an encapsulation or coating process, or placed at some distance from the blue source, such as a remote phosphor approach.

LED实现白光通常以荧光灯结合蓝色LED芯片的方式非常广泛，类似制作荧光灯的操作方式，当荧光体吸收一部分蓝光，会发出波长较长的光（荧光体浓度决定蓝光被转换的数量）。此外，荧光体可以施加在LED的管芯上，例如，封装或涂覆工艺等。

Again, the LED chip design, package design, and phosphor conversion all contribute to the overall efficacy (lm/W) performance of the LED. In signage applications there are other performance characteristics of LEDs that are important, such as thermal resistance, robustness to the environment, color over angle, chromaticity shift and lumen depreciation over time, to name a few.

除此之外，LED芯片的设计、封装设计和荧光粉转换都有助于提高LED的整体功效。在标识应用中，LED的其他性能也相当重要，例如热阻，对环境的稳定性，颜色的布局，色度的退变都有着影响。

LM-80 Test Data

LM-80测试数据

LED package manufacturers provide long term lumen depreciation and color stability data at various operating currents and temperatures in a test report called LM-80. This information can be used to extrapolate estimated life performance of an LED in real world applications. It is from this information, along with the thermal properties of the LED in the sign module into which it is built, that a sign module manufacturer can estimate long term life performance of a sign module.

LED封装制造商从LM-80的测试报告中，能掌握在各种工作电流和温度下，LED照明的流明衰减程度和颜色稳定性的数据。根据该数据，以及LED在标识模块中的热性能，标识制造商可推断出正在应用中的LED照明的寿命。

The biggest enemy affecting long-term performance of the LED is heat. Heat can affect multiple components of an LED package resulting in more rapid lumen depreciation and chromaticity shift over time. The faster the lumen depreciation, the shorter the effective life of the LED as depicted in the figure below.

按使用寿命长短来看，影响LED的因素要属热量，热量可以影响LED的多个部件，从而加速色度的衰减，流明衰减得越快，LED的有效寿命会越短。

In choosing a discrete LED package supplier for making LED sign modules, what does a reputable manufacturer look for in relation to LED quality? Here are a few of the more important properties:

标识制造商在选择使用LED来制造标识时，他们会从以下一些重要的属性来判断LED的质量和功效：

· Energy efficiency

· 能源效率

· Thermal resistance

· 耐热性

· Durability

· 持久性

· Lumen Maintenance

· 修理维护

· Chromaticity Shift

· 色彩转换

· Light Distribution

· 光线分布

· Color over Angle (color distribution)

· 颜色布局

· Color Consistency

· 色调一致性

What does this all mean to the sign maker, and how do you know what you are getting in your LED sign module? Well, ask questions. Know what LED is used in the module you buy. Understand the thermal limitations of the module. The difference between a sign module made with a quality LED and one made with one of suspect quality performance can be the difference between a happy, loyal, long-term customer and the other kind.

LED的每一种属性对于标识制造商来说都非常重要，他们需要了解清楚在LED标识模块中的组成部分，模块中使用的是什么类型的LED。我们相信，为客户提供一个质量可靠LED照明，彼此才能建立起一种快乐而长期的合作关系。