How Laser Projector Works?

Firstly, let’s clarify what is the laser projector.

A few years ago the laser projector couldn’t be anything else than some kind of a laser display system that was use for performing laser shows. Back then only such projectors used laser as source of light.

But as the laser technology developed, lasers became feasible for other sectors of the entertainment industry and very quickly started to replace conventional video projector lamps; mainly due to their short life span. And so the term “laser projector” now also stands for such video projectors, which use laser as their source of light.

But, we at Kvant Lasers develop and manufacture laser display systems. So when we say “laser projector”, we always mean laser display system, show laser light or whatever the lasers for shows are or can be called.

So..how Kvant laser projector works?

The coherent laser light is emitted from the semiconductor laser diode and travels through various optical parts and components, which shape it into even, narrow and low divergence laser beam. All this is happening within a block which we call a laser module.

The laser projector can consist of one or more laser modules of the same or different colours. By mixing different colours together we can get other colours; e.g. mixing red, green and blue laser beams together, and in the correct ratio, will result in the white laser beam.

When the beam leaves the laser module, it is steered towards the scanning system. On this path, it may join with other beams from other laser modules, if there’s more of them in the system.

The scanning system is typically made of two, fast rotating galvos, with tiny mirrors attached to their shafts. The galvos are offset by 90 degrees to each other, which means that each of them controls the beam reflection (movement) on one of the two X and Y axes.
The laser beam hits the first scanner and bounces off it to the 2nd scanner. By working together, the scanners make it possible to move the laser beam into desired position, allowing us to draw all kinds of shapes.
The laser beam (or drawn shape) then travels from the scanners via the output aperture towards the audience.

This all means that whatever comes out from the laser projector and however 3D, static or moving it appears, it’s always made of a single, fast moving laser beam.

The main functions that we control via laser control software to work with lasers effectively are:

• power output of each laser module (intensity)
• blanking of each module within the system (ability to switch laser module ON and OFF)
• movement of X and Y scanners
  

By using these control functions we can change the brightness and colours of beams and drawn shapes, we are able to perform several shapes at once without them being connected together (using blanking to jump from one to another) and to perform static and moving shapes as well as graphic animations.

This is the basic principle of operation of any professional laser projector that is used for laser displays.