| 摘要 |
<p>To study and measure visual fields, a CRT displays to a patient fixation points anywhere in the field and a test stimulus movable and with brightness adjustable over 10000:1; background brightness also adjustable. Characters and graphics can also be displayed. A second CRT is provided as the practitioner's monitor. Main components of the central processor controlling the display are microprocessor (1), RAM (2) and EPROM (3) holding program, instruction decoder (4) and buffers (5, 6). Other components not shown are 9 video generator including character patterns stored in an EPROM, character memory and a clock locked to the one in the microprocessor (1); a video mixer including fixation point generator and D/A converters passing signals for setting the brightness of the best stimulus and background; and a video output amplifier combining the test stimulus, fixation point and background signals together with facilities for erasure. <IMAGE></p> |
