Luminescent tube features are divided into round light, […]
Luminescent tube features are divided into round light, square light, rectangular, surface light tube, lateral tube, surface mount with a miniature tube. According to the diameter of the circular lamp is divided into φ2mm, φ4.4mm, φ5mm, φ8mm, φ10mm and φ20mm and so on. In foreign countries, a φ3 mm LED is usually designated T-1; a φ5 mm is denoted as T-1 (3/4); and a φ4.4 mm is designated T-1 (1/4) [6-8]. The angular distribution of circular luminous intensity can be estimated from the half-value angle. There are three types of luminous intensity distribution:
1) High directivity. Generally pointed epoxy package, or with metal reflective cavity package, and without scattering agent. Half-value angle of 5 ° ~ 20 ° or less, with a high directivity, can be used for local lighting, or photodetector together to form an automatic detection system.
2) Standard. Usually for indicator light, the half-value angle is 20 ° ~ 45 °.
3) Scattering type. This is a larger viewing angle indicator with a half-value angle of 45 ° to 90 ° or greater and a high amount of scattering agent.