Often science fictions predict the actual inventions of science and technology. For instance, 20,000 leagues under the sea was written in 1870, while submarines were in highly experimental stage and not at all successful, and stories about flying in rockets into space appeared long before the first manned space flights. Just so, dangerous and mysterious beams were well known in fiction long before the first laser beams were actually discovered in 1960. Star trek, quick off the mark in 1966 used beams and ray guns, but this sort of idea goes right back to Tolstoy in the 1920’s, Jules Verne in 1896 and HG Wells in 1898. Lasers used in weaponry are supposedly still in the experimental stage, but for quite a long time now, lasers have revolutionised the building trade.
LASER is an acronym for Light Amplification by Stimulated Emission of Radiation. It is believed that ‘Oscillation’ would be more correct than ‘Amplification’……… but, who wants to use the word LOSER?
When lasers were first developed, it was believed that the ray had potential danger. Indeed even low powered lasers are hazardous to eyesight. Lasers are usually labelled with a number that identifies the class of potential danger it may have.
• The kind of laser used in CD players is considered safe as it is enclosed. [This is type l/1]
• Laser pointers up to 1 mW are considered safe, as the normal blink reflex will protect the eye. [This is type ll/2]
• Lasers up to 5 mW hold a slight risk to eyes. One should never stare into this beam. [This is type llla/3R]
• The type lllb/3B laser damages eyes immediately.
• The type lV/4 laser is dangerous and can cause eye and skin damage. It is used in industrial and scientific applications.
When lasers are used for cutting, protective eyewear and gloves should be used. This is not normally necessary for pointers and construction laser beams.
Have a look at most ‘pre-laser’ houses and you will see quite amazing irregularities in walls, corners, tiles and even woodwork. That is because builders and artisans were reliant on short spirit levels, plumb lines and their own ‘by eye’ judgement. Today the accuracy of building is almost ensured. To start with. there were simple hand held lasers with spirit levels to hold against surfaces and shoot out a beam. Even these made a huge difference to the accuracy and alignments. But today, a wide variety of laser tools have been developed. These give the builders the reference lines that are critical to absolute accuracy. The wide variety of different types means that there is a laser tool for every application. Most of the latest technological tools are self levelling. Some are suitable for indoor use; others have a laser ray that is clearly visible for outdoor use. Some are useful for short distances, while others cover much longer distances. There are even some that have laser rays in multiple directions, when set up in one spot. This ensures that the angles are marked out correctly in relation to one another.
For any laser measuring device need in