PCR light source:For the irradiation end of the rapid PCR instrument, if the diameter of 5/8/10mm in-line LED is used, the optical path is shown in Figure 1 after optimized design. The light emitted by the in-line LED is first collimated by a plano-convex glass lens, and then passed through a tape Filter the light through the filter, and finally condense the light into the fiber through a glass spherical lens. Plano-convex glass lens and filter, glass ball lens fiber pass light, numerical aperture NA = 0.56. Separation between filter and glass ball lens = 3-5mm. The light spot at the end face of the fiber is shown in Figure 2. ZEMAX simulation found that the energy utilization rate of light is about 25.658%, compared with the packaged SMD LED (the energy utilization rate of light is about 85%)