Abstract: A multi-shade video conversion system is described to provide an enhanced "Macintosh SE/30" computer to display multi-shade images on the "SE/30" internal CRT. The conventional "SE/30" computer has a microprocessor motherboard, an expansion slot, and an internal CRT. An internal CRT amplifier apart from the motherboard normally receives and responds a binary video signal from the microprocessor motherboard to drive the internal CRT. The conversion system comprises a video frame buffer expansion board, a replacement analog CRT amplifier, and replacement cabling. The frame buffer expansion board generates an analog video signal which is selected provided to the replacement CRT amplifier, allowing multi-shade images to be displayed in the internal CRT. The frame buffer expansion board also has an auxiliary video output port to drive an external CRT. The replacement cabling supplies the motherboard binary video signal to the expansion board rather than to the replacement CRT amplifier.

Abstract: An apparatus to modulate the intensity of a pixel displayed on a screen focused optical energy from a broadband source onto a reflective first face of a planar member. The first face is disposed in said first propagation path at a selected angle thereto to direct optical energy along a second propagation path. A planar mirror is disposed in the second propagation path. The plane of the mirror is actuatable to orientate the mirror within a range of angles to said second propagation path between a first angle limit and a second angle limit. A second focusing lens disposed in the second propagation path to focus optical energy reflected from the first face onto the mirror.

Abstract: A graphic image is displayed on a CRT screen according to the coordinate data which is sequentially read out of a memory. The memory comprises a first storage area which stores character image coordinate data and a second storage area which stores graphic image data such as signal wave. The ratio of addressing times for the first and second storage areas of the memory is set to 1:n. Accordingly, the graphic image is irradiated on the CRT screen n times more than that of one character image. Since the irradiation period of time of each spot is defined by a clock pulse width, there is no irradiation variation from one spot to another spot.