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测量电磁辐射是新照明应用（如LED和新世代发射二极管（OLEDS））开发的关键方面。这可以使用辐射法或光度法来传递。
辐射技术是一种明确的科学方法，旨在衡量辐射在太空中的分布。辐射方法与光度计技术明显不同，后者认为人类可以看到辐射的方式，即根据人眼的敏感性随波长的波动。
辐照is the strength of light, which is measured in watts per square meter. For example, light sources that have an irradiance of one Watt/m² at a set distance of green light, are perceived by the human eye as considerably brighter than the same light with an irradiance of one Watt/m² of blue or red light viewed at the same set distance. Knowing this, radiometry can be used to deliver an accurate assessment of light sources.
哪些测量值是辐射测量值？
Radiometry is the discipline of measuring levels of optical radiation in an area of the electromagnetic spectrum. It tends to be confined to the measurement of infrared, visible, and ultraviolet light using specially calibrated optical apparatus.
使用辐射法来描述光源可能很复杂。它需要角，空间和光谱和时间尺寸。当使用辐射指定时，最好先简化可能的要求来使用一些特定的几何和光谱概念。
任何能够产生可测量输出的光敏设备都可以用作辐射计，它们通常会在温度（电气测量）或电性能（电流，电压或电阻）中产生变化。在大多数情况下，检测器的输出与校准标准相关联，以表明检测器准确吸收的光量。
辐射测定法与辐射功率有关，即辐射功率出现光源并撞击表面，即辐射发射（向外）和辐照度或入射辐射。
考虑几何和光谱因子
当测量辐射源的辐射指定时，必须考虑系统的几何和光谱方面。我们不仅要考虑发射或摄入的辐射（光）的力量，而且还考虑了它在表面及其方向上的影响。
如果光源从（扩散）表面发射，则必须考虑发出的光的角度。这些类型的表面是“兰伯特发射器”，因为它们遵守了兰伯特余弦定律的光发射角度。
其他光源可能是从点源（例如气体放电）直接的，这些光源沿各个方向散发出来。在这样的情况下，以三个维度发射的辐射在两个维度上取决于角度范围。这证明了实体角的概念，等于单位球上的圆形区域（您将锥体转换为角度）。这样的计算允许将光能的尺寸和面积等同起来，以提供可再现的测量。
常见的几何描述
辐射指定中的标准几何描述定义为通量，辐照度，辐射强度和辐射。
- 磁通（（瓦特）是从各个方向发出的完整光电能力。通量可以用ulbricht或集成球体测量。从灯泡等物品中排出的光总数称为其通量。它是一个球体，其大小取决于光源的功率和比例。它具有带有光谱仪的内部扩散白色涂层和内部的点光源，通过间接反射率测量光源的总磁通/功率。
- 辐照（（瓦/m2）：这是每单位表面积的表面上撞击的通量。
- 辐射强度（（瓦/sr): Small radiant objects can be treated in radiometry as point sources. For these types of objects, the flux released per unit solid angle is called the intensity (sr =Steradian). Thus, intensity could be seen as the capability of a penlight to provide light onto a faraway target.
- Radiance（（瓦/m2/sr): For bigger radiant sources this is the flux emitted per unit projected area per unit solid angle, this amount is the radiance. Similar to intensity, radiance can fluctuate with the direction from the object to the viewer. Any object with continuous radiance in all directions is labeled Lambertian. Typical examples of Lambertian objects are the surface of a fluorescent light tube and a highly matte sheet of paper.
Geometries can also be demonstrated in their spectroradiometric equivalent. For example, the spectroradiometric flux (瓦特/nm): In this measurement, the spectrum of a light source is defined by its spectral density, in units of power per wavelength. This can also be determined in units of power per frequency.
Measurements like this can also be used to gauge the luminous flux (in lumens) and associate with the response of the human eye. Spectral irradiance, spectral radiant intensity and spectral radiance are similar to their radiometric equivalents, only providing all measurement data per wavelength.
照明行业和辐射测量
In the lighting industry, new light sources such as LEDs and OLEDs are currently being studied. In current LEDs, heating effects have made measurements extremely important. This is because the heat has a direct effect on the spectral power distribution (SPD) of the LEDs and in turn the color output. In these types of studies, the total flux and SPD from a source are normally measured in an integrating sphere. The sphere and radiometer system are usually calibrated using a recognized reference source of known output flux.
在设置照明系统时，研究人员必须意识到情况。当计算弥漫性，均匀点亮的照明表面时，（准直的）镜头可以适当地测量光源的特性。但是，如果辐照度来自大型源，例如天窗或房间灯，则可能需要在检测器前面以辐射模式或以辐照模式集成球体的扩散器。根据光学构型的不同，诸如Rhea和Hera之类的探测器以辐照度，辐射功率，辐射通量或辐射率直接校准，以直接读取。
用于放射测量的Admesy的光谱仪
RHEA是一个灵活的平台，用于可配置的光谱测量范围在200至1100 nm之间。它允许以缝隙尺寸，光栅和光学元件的方式进行选择，以允许在现代光学系统中进行辐射测量的自定义光谱测量解决方案。RHEA系列可以使用5、10或20毫米的准直镜，余弦校正器以及纤维连接器（如果需要）配置。
来自Admesy的Rhea系列光谱仪
这Rhea has the adaptability that a spectroradiometer has for OEM integration, display, lighting and appearance measurements in both production and laboratory environments. The system is extremely sensitive, it has excellent linearity and it possesses a cooled high-end CCD detector (-10 °C). The Rhea measures distinct parameters such as CCT, CRI, Yxy, radiometric and photometric, spectrum, PAR. Functions include: auto range, dark current compensation, integrated filter wheel with ND filters and shutter function and a high optical throughput design. More fundamental in radiometry, the system gives internal calculations for the standard parameters.
这赫拉是具有自动范围函数的精确光谱仪，在健壮和紧凑的外壳中具有出色的线性性。光谱范围包括VIS和UV-NIR：380-780 nm，360-830 nm，200-1100 nm。
来自Admesy的HERA系列光谱仪
HERA配有固定的[镜头或余弦校正器]或光纤设置。它旨在测量各种参数，包括XY，CRI，CCT，辐射和光度法，PAR，Spectrum。有一个自动范围的功能，并结合出色的线性和深色电流补偿。HERA的灵活性使其非常适合一系列照明开发应用。
克服LED开发中的新障碍
At present, the LED industry is facing a problem. Heating effects are making it hard to calculate new style LED performance correctly. Measurements that were easy to perform before are now more tricky because the LED junction and phosphors heat up in the course of the measurement.
Even if heating is at a minimum, heated phosphors and junctions create less light, and the emitted light is moved in peak wavelength. This causes the R&D to become more complicated and makes it hard to exchange measurement data that represents the correct use of the light source. Therefore, it is difficult to precisely rate LEDs at their true output.
此外，对LED和固态照明产品的生产过程的固有挑战是与驾驶员相关的视觉特征的变化，例如亮度，颜色和闪烁，这甚至可以在同一生产批处理中发生。为了确保质量和一致性，在开发LED并在整个生产过程中完成100％检查时，衡量这些光学特性至关重要。
HERA和RHEA是LED开发的理想光谱仪。两种光谱仪都具有可靠的室内外壳，可针对恶劣的生产环境进行了优化。这是评估新样式LED的理想选择，在该LED中可能需要进行大量冷却来测试其功能参数。两种设备都具有测试参数范围的灵活性，并处理用于在高通量生产环境中使用的数据。
与星星光度计，Admesy允许以高精度，可重复性和速度进行全面检查。
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参考
- A.V. Arecchi，T。Messadi和R.J. Koshel（2007）。照明现场指南。Spie Press，贝灵汉，华盛顿。
- Rolf R. Hainich, Oliver Bimber, Displays: Fundamentals & Applications, Second Edition
- McCluney，W.R。（1994）。放射线和光度法简介，波士顿和伦敦Artech House，Artech House。
- Smith，W.J。（2007）。现代光学工程，第4版，Spie Press，McGraw-Hill，纽约。
- Wolfe，W.L。（1998）。辐射学简介，Spie Press，Bellingham，Wash
- Jeff Hulett，确保您的轻度测量方法不会低估您的LED，LED的杂志，2017年3月8日
This information has been sourced, reviewed and adapted from materials provided by Admesy.
有关此消息来源的更多信息，请访问Admesy。