A light source, comprising: an excitation light source; an excited light supplying device; a partially coating film; and a light supplementing device; wherein the excitation light source is configured to emit excitation light, the excited light supplying device is configured to generate excited light under irradiation of the excitation light, the partially coating film is located in a light path of the excitation light and a light path of the excited light, the partially coating film comprises a first area and a second area, the first area is configured to transmit an amount of the excitation light to form a main path light and reflect another amount of the excitation light to form a side path light, an optical axis of the main path light being non-collinear to an optical axis of the side path light, the second area is configured to reflect all incident light, the excited light supplying device is located in a light path of the main path light and deviates from a light path of the side path light, and the excited light supplying device is configured to generate the excited light propagating toward the partially coating film after being excited by the main path light; or the partially coating film is located in a light path of the excitation light and a light path of the excited light, the partially coating film comprises a first area and a second area, the first area is configured to reflect an amount of the excitation light to form a main path light and transmit another amount of the excitation light to form a side path light, an optical axis of the main path light being non-collinear to an optical axis of the side path light, the second area is configured to transmit all incident light, the excited light supplying device is located in a light path of the main path light and deviates from a light path of the side path light, and the excited light supplying device is configured to generate the excited light propagating toward the partially coating film after being excited by the main path light, the light supplementing device is located in the light path of the side path light and configured to perform light homogenization to the side path light and generate supplemental light propagated to the partially coating film, and the supplemental light, after passing through the first area of the partially coating film, is combined with the excited light, wherein the supplemental light supplements the excited light to form a uniform light spot. an excitation light source; an excited light supplying device; a partially coating film; and a light supplementing device; wherein the excitation light source is configured to emit excitation light, the excited light supplying device is configured to generate excited light under irradiation of the excitation light, the partially coating film is located in a light path of the excitation light and a light path of the excited light, the partially coating film comprises a first area and a second area, the first area is configured to transmit an amount of the excitation light to form a main path light and reflect another amount of the excitation light to form a side path light, an optical axis of the main path light being non-collinear to an optical axis of the side path light, the second area is configured to reflect all incident light, the excited light supplying device is located in a light path of the main path light and deviates from a light path of the side path light, and the excited light supplying device is configured to generate the excited light propagating toward the partially coating film after being excited by the main path light; or the partially coating film is located in a light path of the excitation light and a light path of the excited light, the partially coating film comprises a first area and a second area, the first area is configured to reflect an amount of the excitation light to form a main path light and transmit another amount of the excitation light to form a side path light, an optical axis of the main path light being non-collinear to an optical axis of the side path light, the second area is configured to transmit all incident light, the excited light supplying device is located in a light path of the main path light and deviates from a light path of the side path light, and the excited light supplying device is configured to generate the excited light propagating toward the partially coating film after being excited by the main path light, the light supplementing device is located in the light path of the side path light and configured to perform light homogenization to the side path light and generate supplemental light propagated to the partially coating film, and the supplemental light, after passing through the first area of the partially coating film, is combined with the excited light, wherein the supplemental light supplements the excited light to form a uniform light spot.