Venous positioning projector

A venous positioning projector, comprising:

• an infrared light source module, configured to output a first infrared light to a target surface;
• a light splitting element, disposed on a transmitting path of a second infrared light reflected by the target surface;
• an infrared light image capture module, comprising a filter and an infrared light image capture element, wherein the second infrared light transmitted to the light splitting element is transmitted to the filter through the light splitting element, the filter allows the second infrared light to pass through, and the infrared light image capture element is disposed on the transmitting path of the second infrared light passing through the filter and receives the second infrared light;
• a processor, coupled to the infrared light source module and the infrared light image capture element, wherein the processor generates venous image data according to the first infrared light and the second infrared light;
• a visible light projection module, coupled to the processor and generating a visible light based on the venous image data, wherein the light splitting element is further disposed on a transmitting path of the visible light, and the visible light is transmitted to the target surface through the light splitting element to generate a venous image, wherein
• the infrared light image capture module and the visible light projection module share an optical axis between the light splitting element and the target surface,
• the infrared light source module comprises at least one first light-emitting element and at least one second light-emitting element, the at least one first light-emitting element and the at least one second light-emitting element are disposed on opposite sides of the optical axis, the first infrared light comprises a first light output by the at least one first light-emitting element and a second light output by the second light-emitting element, the first light and the second light have different central wavelengths, the at least one first light-emitting element and the at least one second light-emitting element are turned on in a first time period and a second time period, respectively, the second infrared light comprises a third light and a fourth light that are reflected by the target surface in the first time period and the second time period, respectively, the filter comprises a first filter region and a second filter region, the first filter region allows the third light to pass through and filters the fourth light, the second filter region allows the fourth light to pass through and filters the third light, the first filter region cuts into a transmitting path of the third light in the first time period, and the second filter region cuts into a transmitting path of the fourth light in the second time period, the first time period and the second time period are mutually exclusive,
• wherein the filter rotates about a central axis to switch between different filter regions on the same optical path;
• and
• a transparent protection element, disposed between the light splitting element and the target surface, wherein the transparent protection element is a transparent substrate with a metal oxide layer.