A light module, comprising: a support body, wherein the support body has a light path channel; a substrate, wherein the substrate is connected to the support body and is located at one end of the light path channel, the substrate is provided with a light source, and the light source is located in the light path channel; and a light-transmitting element, wherein the light-transmitting element is connected to the support body, so as to seal an opening at the other end of the light path channel; wherein a side face of the light-transmitting element that faces towards the light source is provided with a first electrical contact point, a second electrical contact point, and a photosensitive coating capable of converting light energy of the light source into electrical energy, the first electrical contact point and the second electrical contact point are electrically connected by the photosensitive coating, and the first electrical contact point and the second electrical contact point are configured to connect to a detection module, so that the detection module detects a value of a voltage across the first electrical contact point and the second electrical contact point; and a region that corresponds to the light path channel and that is on the side face of the light-transmitting element that faces towards the light source is a light-transmitting region, the light-transmitting region is provided with an optical structure region and at least part of the region of the photosensitive coating, and the photosensitive coating and the optical structure region do not overlap; characterised in that the first electrical contact point and the second electrical contact point are located on a same side of the optical structure region, and the photosensitive coating is provided in a strip shape around the optical structure region. a support body, wherein the support body has a light path channel; a substrate, wherein the substrate is connected to the support body and is located at one end of the light path channel, the substrate is provided with a light source, and the light source is located in the light path channel; and a light-transmitting element, wherein the light-transmitting element is connected to the support body, so as to seal an opening at the other end of the light path channel; wherein a side face of the light-transmitting element that faces towards the light source is provided with a first electrical contact point, a second electrical contact point, and a photosensitive coating capable of converting light energy of the light source into electrical energy, the first electrical contact point and the second electrical contact point are electrically connected by the photosensitive coating, and the first electrical contact point and the second electrical contact point are configured to connect to a detection module, so that the detection module detects a value of a voltage across the first electrical contact point and the second electrical contact point; and a region that corresponds to the light path channel and that is on the side face of the light-transmitting element that faces towards the light source is a light-transmitting region, the light-transmitting region is provided with an optical structure region and at least part of the region of the photosensitive coating, and the photosensitive coating and the optical structure region do not overlap; characterised in that the first electrical contact point and the second electrical contact point are located on a same side of the optical structure region, and the photosensitive coating is provided in a strip shape around the optical structure region.