How do beam splitters help colour television cameras produce red green and blue images?

In colour television cameras, beam splitters—specifically dichroic mirrors—are used to separate incoming light into the three primary colours: red, green, and blue.12

Rather than using a single sensor with a filter pattern, traditional high-quality colour cameras employ an optical system that directs the image onto three separate sensors (such as charge-coupled devices or camera tubes). The beam-splitting system uses colour-selective mirrors that reflect light of one specific colour while transmitting the remaining wavelengths.12

By combining these mirrors with additional colour filters to refine the selection, the system directs a distinct blue image to the first sensor, a green image to the second, and a red image to the third. Because the optical system ensures each sensor receives an identical image of the same geometric shape, the camera can generate three separate electrical signals that represent the primary colour components of the scene. These signals are then processed to produce a full-colour image.2