1.1 本试验方法包括测量由透明部件（如飞机挡风玻璃和雨篷）施加的光线的角度偏差。结果不受横向位移的影响，并且可以在相对较短的光程长度内执行该过程。这不是裁判标准。这是一种通过透明窗口测量角度偏差的简便方法。 1.2 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。 1.3 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====== 5.1 衡量透明部件光学质量的一个指标是其角度偏差。过度的角度偏差或整个零件的角度偏差变化可能会导致通过零件观看的场景发生可见失真。 在某些飞机透明度应用领域，即配备平视显示器（HUD）的飞机，角度偏差及其检测和量化至关重要。HUD可能需要严格控制位于HUD组合玻璃和外部环境之间的透明部分（挡风玻璃或顶篷）的光学元件。配备HUD或类似设备的军用飞机需要精确了解挡风玻璃或顶篷对图像位置的影响，以保持武器瞄准精度。 5.2 两个光学参数可以改变图像位置。 第一个是横向位移，它是相对于视线倾斜的任何透明度所固有的。横向位移的影响在距离上是恒定的，很少超过一英寸的分数。第二个参数，角度偏差，通常由透明表面的楔形或非平行性引起。角度偏差的影响与偏差角度的切线有关，因此图像位置位移的幅值随着图像和透明度之间的距离而增加。因此，角度偏差的量化是两个参数中更为关键的。 这两个参数如所示 图X1.1 .

1.1 This test method covers measuring the angular deviation of a light ray imposed by transparent parts such as aircraft windscreens and canopies. The results are uncontaminated by the effects of lateral displacement, and it is possible to perform the procedure in a relatively short optical path length. This is not intended as a referee standard. It is one convenient method for measuring angular deviations through transparent windows. 1.2 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. 1.3 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 ====== 5.1 One of the measures of optical quality of a transparent part is its angular deviation. It is possible that excessive angular deviation, or variations in angular deviation throughout the part, will result in visible distortion of scenes viewed through the part. Angular deviation, its detection, and quantification are of extreme importance in the area of certain aircraft transparency applications, that is, aircraft equipped with Heads-up Displays (HUD). It is possible that HUDs will require stringent control over the optics of the portion of the transparency (windscreen or canopy) which lies between the HUD combining glass and the external environment. Military aircraft equipped with HUDs or similar devices require precise knowledge of the effects of the windscreen or canopy on image position in order to maintain weapons aiming accuracy. 5.2 Two optical parameters have the effect of changing image position. The first, lateral displacement, is inherent in any transparency which is tilted with respect to the line of sight. The effect of lateral displacement is constant over distance, and seldom exceeds a fraction of an inch. The second parameter, angular deviation, is usually caused by a wedginess or nonparallelism of the transparency surfaces. The effect of angular deviation is related to the tangent of the angle of deviation, thus the magnitude of the image position displacement increases as does the distance between image and transparency. The quantification of angular deviation is then the more critical of the two parameters. Both parameters are illustrated in Fig. X1.1 .