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Arabic Outdoor lighting must read- Do you really know how to look at the beam angle of outdoor floodlights?
Many friends asked me that: in the technical requirements for LED night scene outdoor lighting applications, in the lamp efficiency table of white light LED floodlights, Note 1: B10% refers to the beam angle calculated based on 10% of the maximum light intensity value, and B50% refers to the beam angle calculated based on 50% of the maximum light intensity value. What do you mean by B10% in this sentence?
B10% refers to the 10% light intensity angle, also known as the 1/10 light intensity angle. It is often expressed as a Field Angle in English and often translated into a full angle in Chinese. In practical applications, it often appears in the North American IES standard. It is also often seen in the outdoor floodlight specification books of domestic manufacturers. It is also used in the technical requirements for LED night scene lighting applications.
When we look at the beam angle, most of the time we look at the half-intensity angle, which is the angle corresponding to the light intensity value that is half of the maximum light intensity value. Take the following figure as an example. The maximum light intensity value of the light distribution curve in the figure below is 12889cd. I divide the light intensity range into 10 equal parts. In this way, the 50% light intensity value is located at the 5th equal circle. The angle between the intersection of the 5th equal circle and the light distribution curve, the origin is the half-intensity angle. The half-intensity angle of the light distribution curve in the figure below is 29°.
Similarly, to find the 10% light intensity angle, divide the maximum light intensity value into 10 equal parts. Then, measure the angle between the first equal-division circle and the light distribution curve to the line connecting the origin. As shown in the figure below, the 10% light intensity angle in the figure below is 47°.
The above is an explanation of how to read the angle of 10% light intensity angle.
Many people may say that it is still difficult to see with just a light distribution curve. The light distribution curves in paper atlases are displayed very small, and it is difficult to read the angle.
If we have the ies file provided by the manufacturer, it is very convenient to open it with software and read it directly. For example, the light distribution curve above is displayed as shown below when opened with software.
When the software is used to open the parameter reading, the following parameters will be displayed, including the 50% light intensity angle and the 10% light intensity angle. The figure below shows 29.2° and 47.6° respectively, which is consistent with what we read manually.
