Displays news

Fibre opt ics i l luminates facias Fibre optics is being used for instrument facia illumination by R H Technical Industries. The day- light-viewable lighting comprises a ribbon laminate of optical fibres, typically 15 fibres/3 mm width, which is abraded to allow selec- five transmission of light along the length of the flexible laminate. Precise abrading of the fibre assures uniformity of illumination at correct points along the total length of the fibre optic laminate.

Advantages cited by the manu- facturer include the low voltage required, compared with existing methods of total dial/switch illumi- nation; facias can be custom designed for specific applications; the light source is cold and uniform; the light source can be located a convenient distance from the display; the facias are typically only 0.5 nun thick; and the temperature range is -40°C to + 80°C.

Several applications are suggested by the manufacturer. The fibre optic light-guided lami- nate is itself laminated to the rear of a self-supporting polyester/ polycarbonate dial or filter.

Operating from a single source of fight, which may be some distance from the display, the whole of the dial legend is illuminated without risk of heat distortion from bulbs. The designer can, therefore, dramatically reduce the instru- ment cluster depth, and, for auto° motive displays, can actually incorporate it into the dashboard assembly.

In illuminating LCDs, fibre optics offers complete rear illumi- nation of portable instrumentation, and constant readability of the dis-

play. It replaces less effective high-voltage systems currently used for this purpose.

The existing method of rear illu- mination for membrane switches, while effective, cannot easily be incorporated into a portable unit. Fibre optics, however, offers multiple colour choice, and strong uniform lighting in every kind of membrane switch construction. The fibre optic laminate is inserted between the switch cir- cuitry and the graphic overlay.

R H Technical Industries Limited, Easton Lane, Winchester, Hampshire S02~ 7RR, tiE.

A b r a d e d optical f ibres are u s e d b y RHTI to i l luminate facia panels , such as car dashboards

V'DUs are safe

The visual display unit is given a clean bill of health by a Health and Safety Executive (HSE) booklet, W o r k i n g with VDUs. The lO-page booklet answers a series of ques- tions, commonly asked by VDU users concerned about the effects on their health.

Perhaps the question most asked in this regard is, can VDU radiation be harmful to health? HSE says that radiation from a VDU is much less than that from natural environmental sources, such as the sun, and is well below the levels considered harmful.

Much of the rest of the publi- cation emphasizes this point, things such as eyestrain, head- aches, and neck, shoulder and

arm pains being attributed to the way in which VDUs are used, rather than to the machines them- selves.

The author of the booklet, Dr Colin Mackay, said, 'Planning and a sensible approach to operating procedures and timings will pre- vent most problems arising. There is no need to resort to protective gadgets or to feel afraid of the VDU. Properly used, it is a useful tool. What we have to avoid is new-technology sweatshops where the working environment is hostile and conditions make for problems. It is not the machine at fault in most cases, but the way in which it is used.'

In answer to recent fears of the risks of VDUs to pregnant women,

the HSE says that, 'The latest studies have not been able to show a link between miscarriage or birth defect and VDUs. In the population as a whole, one in five to one in ten known pregnancies ends in miscarriage. Occasionally, however, a group will show a much higher or lower level than these average figures. Higher levels have been reported among groups of VDU operators, but investigations show that they are not peculiar to VDU work and are to be expected on the basis of statistical chance rather than a result of VDU work.'

Health and Safety Executive, Regina House, 2S9/g69 Old Marylebone Road, London N~I 5RR, UE.

DISPLAYS, JANUARY 1986 49