1982
Sinclair files patent for the Spectrum display system
Sinclair Research files a patent application covering the innovative display system used by the ZX Spectrum.
The invention, titled “Display for a Computer”, was developed by Richard Altwasser and assigned to Sinclair Research Ltd. It describes a method of generating a colour television display using relatively simple hardware, combining pixel information with separate colour and attribute data.
The system was an important part of the ZX Spectrum's design. Rather than storing a complete colour value for every individual pixel, the Spectrum stored the pixel pattern separately from the colour attributes. Each 8×8 pixel character cell had an attribute byte specifying its foreground and background colours, together with the BRIGHT and FLASH properties.
This approach dramatically reduced the amount of memory required for the display while still allowing the Spectrum to produce a colourful television picture using inexpensive hardware.
The patent's technical drawings show the circuitry used to combine the pixel and attribute information and generate the colour video signal. The design became one of the defining technical characteristics of the ZX Spectrum.
The patent therefore provides an interesting insight into the engineering behind the computer just one day before the ZX Spectrum was officially launched.
The invention, titled “Display for a Computer”, was developed by Richard Altwasser and assigned to Sinclair Research Ltd. It describes a method of generating a colour television display using relatively simple hardware, combining pixel information with separate colour and attribute data.
The system was an important part of the ZX Spectrum's design. Rather than storing a complete colour value for every individual pixel, the Spectrum stored the pixel pattern separately from the colour attributes. Each 8×8 pixel character cell had an attribute byte specifying its foreground and background colours, together with the BRIGHT and FLASH properties.
This approach dramatically reduced the amount of memory required for the display while still allowing the Spectrum to produce a colourful television picture using inexpensive hardware.
The patent's technical drawings show the circuitry used to combine the pixel and attribute information and generate the colour video signal. The design became one of the defining technical characteristics of the ZX Spectrum.
The patent therefore provides an interesting insight into the engineering behind the computer just one day before the ZX Spectrum was officially launched.
