1.1 本规程描述了确定表面光散射量和角分布的程序。特别是，它侧重于测量双向散射分布函数（BSDF）。BSDF是一种方便且被广泛接受的表达光散射水平的方法，可用于多种目的。当考虑反射散射时，它通常被称为双向反射分布函数（BRDF），或当考虑透射散射时，它通常被称为双向透射分布函数（BTDF）。 1.2 BSDF是样本外观的基本描述，许多其他外观属性（如光泽、雾度和颜色）可以根据特定几何和光谱条件下BSDF的积分来表示。 1.3 本实践还介绍了表示角度分辨光散射结果的替代方法，包括方向反射因子、方向透射因子和差分散射函数。 1.4 本规程适用于不透明、半透明或透明样品上的BSDF测量。 1.5 本规程适用的波长包括紫外线、可见光和红外区域。在波长小于约0.2µm（200 nm）的情况下，难以获得合适的光源、探测器和低散射光学元件，使其实际应用复杂化。对于大于15µm（15μm）的波长，衍射效应开始变得重要 这使其在更长波长下的实际应用复杂化。与视觉外观有关的测量仅限于可见波长区域。 1.6 本规程不适用于具有显著荧光的材料。 1.7 本规程适用于任意形状的平面或曲线样品。然而，在讨论和示例中只讨论了一个平面样本。用户有责任定义适当的样品坐标系，以指定样品表面上的测量位置以及非平面样品的适当光束特性。 1.8 本规程未提供将测量的BSDF归因于任何散射机制或散射源的方法。 1.9 本规程不提供将数据从一个波长、散射几何形状、样品位置或极化外推到任何其他波长、散射几何形状、样品位置或极化的方法。用户必须在他或她的应用程序感兴趣的波长、散射几何形状、样本位置和极化处进行测量。 1.10 可以在测量序列中改变任何参数。在测量序列中保持不变的参数在表格数据集或相关文档中报告为标题信息。 1.11 仪器和测量程序是通用的，因此本规程的使用既不排除也不暗示特定仪器。 1.12 对于半导体行业的测量，操作员应参考指南SEMI ME 1392。 1.13 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.14 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 散射的角度分布是表面的一种特性，可能对该表面的中间或最终应用产生直接影响。散射定义了材料的许多视觉外观属性，而分布和波长依赖性的规范对消费品（如汽车、化妆品和电子产品）的适销性至关重要。 光扩散材料用于信息显示应用中，将光从显示元件传播到观察者，此类显示器的性能取决于散射分布的规格。杂散光减少元件，如挡板和墙壁，依赖于具有低漫反射的吸收涂层。镜子、透镜、滤光片、窗口和其他组件的散射会限制光学系统（如望远镜、环形激光陀螺仪和显微镜）中的分辨率和对比度。 4.2 与材料相关的微观结构会影响散射的角度分布，通常可以从该散射的测量结果中推断出特定的性能。例如，粗糙度、材料不均匀性和光滑表面上的颗粒会导致光散射，光散射可用于检测此类缺陷的存在。 4.3 散射光的角度分布可用于模拟或渲染材料的外观。渲染质量在很大程度上取决于对渲染材料的光散射特性的精确测量。

1.1 This practice describes procedures for determining the amount and angular distribution of optical scatter from a surface. In particular it focuses on measurement of the bidirectional scattering distribution function (BSDF). BSDF is a convenient and well accepted means of expressing optical scatter levels for many purposes. It is often referred to as the bidirectional reflectance distribution function (BRDF) when considering reflective scatter or the bidirectional transmittance distribution function (BTDF) when considering transmissive scatter. 1.2 The BSDF is a fundamental description of the appearance of a sample, and many other appearance attributes (such as gloss, haze, and color) can be represented in terms of integrals of the BSDF over specific geometric and spectral conditions. 1.3 This practice also presents alternative ways of presenting angle-resolved optical scatter results, including directional reflectance factor, directional transmittance factor, and differential scattering function. 1.4 This practice applies to BSDF measurements on opaque, translucent, or transparent samples. 1.5 The wavelengths for which this practice applies include the ultraviolet, visible, and infrared regions. Difficulty in obtaining appropriate sources, detectors, and low scatter optics complicates its practical application at wavelengths less than about 0.2 µm (200 nm). Diffraction effects start to become important for wavelengths greater than 15 µm (15 000 nm), which complicate its practical application at longer wavelengths. Measurements pertaining to visual appearance are restricted to the visible wavelength region. 1.6 This practice does not apply to materials exhibiting significant fluorescence. 1.7 This practice applies to flat or curved samples of arbitrary shape. However, only a flat sample is addressed in the discussion and examples. It is the user’s responsibility to define an appropriate sample coordinate system to specify the measurement location on the sample surface and appropriate beam properties for samples that are not flat. 1.8 This practice does not provide a method for ascribing the measured BSDF to any scattering mechanism or source. 1.9 This practice does not provide a method to extrapolate data from one wavelength, scattering geometry, sample location, or polarization to any other wavelength, scattering geometry, sample location, or polarization. The user must make measurements at the wavelengths, scattering geometries, sample locations, and polarizations that are of interest to his or her application. 1.10 Any parameter can be varied in a measurement sequence. Parameters that remain constant during a measurement sequence are reported as either header information in the tabulated data set or in an associated document. 1.11 The apparatus and measurement procedure are generic, so that specific instruments are neither excluded nor implied in the use of this practice. 1.12 For measurements performed for the semiconductor industry, the operator should consult Guide SEMI ME 1392. 1.13 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.14 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 The angular distribution of scatter is a property of surfaces that may have direct consequences on an intermediate or final application of that surface. Scatter defines many visual appearance attributes of materials, and specification of the distribution and wavelength dependence is critical to the marketability of consumer products, such as automobiles, cosmetics, and electronics. Optically diffusive materials are used in information display applications to spread light from display elements to the viewer, and the performance of such displays relies on specification of the distribution of scatter. Stray-light reduction elements, such as baffles and walls, rely on absorbing coatings that have low diffuse reflectances. Scatter from mirrors, lenses, filters, windows, and other components can limit resolution and contrast in optical systems, such as telescopes, ring laser gyros, and microscopes. 4.2 The microstructure associated with a material affects the angular distribution of scatter, and specific properties can often be inferred from measurements of that scatter. For example, roughness, material inhomogeneity, and particles on smooth surfaces contribute to optical scatter, and optical scatter can be used to detect the presence of such defects. 4.3 The angular distribution of scattered light can be used to simulate or render the appearance of materials. Quality of rendering relies heavily upon accurate measurement of the light scattering properties of the materials being rendered.