Carey’s Selenium Camera

Divide the picture into independent sensing points.

Boston civil servant George Carey proposed a complete television concept in 1877. An optical image would fall on multiple selenium elements. Each element would respond to brightness at one small part of the scene and provide an electrical value for a corresponding element at the receiver.

The concept was technologically impractical at large scale because it required many individual connections and precise matched elements. Yet its spatial architecture anticipated later image-sensor arrays.

Light, cathode rays and communication begin to converge.

Eugen Goldstein coined the term cathode rays for the glow produced in evacuated tubes. Alexander Graham Bell's photophone used light to transmit sound, while Bell and Edison both considered systems that might send images as well as audio.

These were not finished televisions, but they supplied three essential ideas: light can carry information, light can alter an electrical property, and an image can be divided into measurable locations.

A camera is a map of brightness values.

Modern CCD and CMOS sensors integrate millions of photosensitive sites on one semiconductor chip. Carey's proposal lacked the electronics to scan and amplify such an array, but the conceptual step—representing an image as local electrical samples—remains fundamental.