Understanding Glare: Causes, Effects, and Observations

[danong]

I have a question about phenomena of glare.

I had read about an article saying that the glare is caused by the effect of fraunhoffer diffraction;

However from my observation is that, even in the near field diffraction, it still occurs the same effect as glare,
the only difference is that the source of illumination is not from sun but artificial light.

And i had referred to some wiki citing that glare is the effect of over-illuminance,
so is that glare is valid for all diffraction patterns rather than just far-field diffraction?

My conclusion is that glare effects is existed everywhere, the only difference is that the illumination-ratio of light source in contrast to environmental illuminance rate.


Your help is much appreciated,
Thanks in advance and have a nice day.

God Bless.



Regards,
Daniel.

 

[AndyW]

Dear Daniel,

Thank you for your question about the phenomenon of glare. I can provide some clarification on the causes of glare and how it relates to diffraction.

Firstly, it is important to understand that glare is a subjective perception of discomfort or annoyance caused by excessive or uncontrolled brightness. It can occur in both natural and artificial lighting conditions, and is not limited to diffraction patterns.

In terms of diffraction, Fraunhofer diffraction is indeed a phenomenon that can contribute to glare. This occurs when light waves pass through an opening or aperture, causing them to diffract and create a pattern of bright and dark areas. In the case of sunlight, this could be seen as a diffraction pattern caused by the sun passing through tree branches or a window frame, resulting in the perception of glare.

However, as you mentioned, diffraction can also occur in artificial lighting, such as from light fixtures or screens. This can also contribute to glare, as the light waves are not evenly distributed and can cause discomfort to the viewer.

Additionally, as you mentioned, glare can also be caused by over-illuminance, which is when the intensity of light is too high for the environment or task at hand. This can occur in both natural and artificial lighting and can contribute to the perception of glare.

In conclusion, glare is a complex phenomenon that can be caused by a combination of factors, including diffraction and over-illuminance. It is not limited to far-field diffraction and can occur in both natural and artificial lighting conditions. I hope this helps to answer your question.

 

[sir-pinski]

Thank you for your question and for sharing your observations on the phenomenon of glare. Glare is a complex phenomenon that can be caused by various factors, including diffraction, over-illumination, and contrast between light sources and the surrounding environment. While Fraunhofer diffraction is one possible cause of glare, it is not the only one, and as you pointed out, artificial light sources can also produce glare similar to that caused by the sun.

In terms of whether glare is valid for all diffraction patterns, it is important to note that diffraction itself is not the only factor in causing glare. Other factors such as the direction and intensity of the light source, the reflectivity of the surrounding surfaces, and the sensitivity of the observer's eyes also play a role in the perception of glare. Therefore, it is possible for glare to occur in both far-field and near-field diffraction patterns, depending on these other factors.

You are correct in saying that glare can be observed in various environments and lighting conditions. It is important to consider the ratio of light sources to the surrounding environment in determining the severity of glare. This is why glare may be more noticeable in artificially lit environments compared to natural outdoor settings.

I hope this helps answer your question and provides a better understanding of the complex nature of glare. Thank you for your interest in this topic and have a great day. God bless.