rCBLUS Lireruture Ten rules for naval display design
Dual phosphor system for CRT
Rules for the design of man-computer dialogues in naval alphanumeric status displays are laid out in a study by the UK Admiralty Marine Technology Establishment. The guidelines are in ten stages and are followed up by three suggested standards.
'A product whose time has come' is RCA's description of the colour CRT. The company has recently entered the high resolution colour display tube market with the introduction of a 13 V tube described in the RCA house journal. The dot matrix screen has a triad spacing of 0.31 mm on a black matrix with two phosphor systems. A full spectrum colour phosphor similar to that used in conventional colour TVs is used for general graphics presentations, and a second, high brightness light blue, phosphor can highlight specific text data,
Considerations for the status displays, or totes as they are termed, start with system task and subtask specifications. Tote pages are then built up, and here care must be taken to ensure a logical sequence and groupings of pages and their layout, according to the report. This is the seed of the 'tote tree'. Following the stages suggested, the tree design should make the resultant task design compatible with system requirements. The standards propose that a map of the tote tree be provided on one tote page and that the user should have something on each page to tell him which pages can be immediately accessed. The tote tree structure should be compatible with expected page usage patterns and so facilitate the display use during operations. M.A. Tainsh Ergonomics 25 (1982) 683
Are you sitting comfortably? A study into VDU workstations by the State Farm Mutual Automobile Insurance Companies in Bloomington, Illinois, has shown the importance of the user being able to make adjustments to his surroundings. Test participants showed a marked preference for terminals where they could adjust the height, angle and distance of the screen and keyboard. They also liked adjustable shairs with contoured seats and back rests with heights and angles which they could set for themselves. T. J. Springer Appl Ergonornics 12 (1982) 211
According to RCA the standard blue chromaticity results in bad legibility of displayed information. This problem can be surmounted by using the standard blue phosphor with both the blue and the green guns. This gives a desaturated colour which is easier to see, but also gives rise to convergence problems. The RCA light blue system avoids both disadvantages to give highly legible alphanumerics and a usable colour area for graphic displays~
R.L. Barbin, T.F. Simpson, B.G. Marks RCA Eng 27 4 (1982) 23
Better mix on LC TV Toshiba's liquid crystal TV has, say workers at the company's electron device development laboratory, a 20 : 1 contrast ratio, 30 ms response time and more than eight grey shades. The improvements have been achieved as a result of work into different nematic LC mixture properties. They conclude that a LC material of birefringence greater than 0.14 and a viscosity lower than 3 mPa s (30 centipoise) must be synthesized by blending LCs of different classes to meet the above parameters. Parallel LC molecular alignment is preferred over perpendicular alignment because response time is cut. Doping of donor
and acceptor dopants to LCs is needed for improved contrast and d c operating lifetime. The Toshiba TV set prototype uses a MOS FET matrix with reflective mode dynamic scattering liquid crystals. The nematic LCs used in the experiments all showed negative dielectric anisotropy and were from phenylcyclohexane, phenylcyclohexanoate, phenyl benzoate, Schiff base and azoxybenzene classes and their mixtures.
S. Matsumoto, K. Mizunoya, H. Tomii Mol Cryst Liq Cryst 87 (1982) 53
The light pen -- too much muscle?
Inputs fail user tests Ergonomic tests on three different input methods to a display revealed all to be less than ideal, but for different reasons. The three input techniques, used in conjunction with TV displays for text-processing in a command and control centre, were a light pen, a touch panel and function keys. The light pen failed on the muscle activity required to use it, the function keys and touch panel on oculographical activity - the amount an operator needs to keep shifting his line of sight. The results, say the test organizers, indicate the need for anthropometric and physiological work system design. In the particular case considered human abilities had not been considered in designing the control centre.
E. Haider, H. Luczak, W. Rohmert Appl Ergonomics 13 (1982) 163
DISPLAYS. J A N U A R Y 1983