How can I make a laser circle of 40cm diameter

[Martin R]

I'm not familiar with laser technology but I have heard that the ratio must si 1:1 when it come to distance of the laser and the size of a laser circle.

For example, if the diameter of circle is 40cm, then the distance to the laser must be 40cm.

How can I make a laser circle of 40cm diameter when the laser is on about 120cm distance? Is this possible?

I would be very thankful if anyone could guide me. Need this in an industial production.

 

[Anthony P]

A mirror spinning on a motor shaft will make circles. The mirror is mounted on the end of the shaft and nearly perpendicular to it. The more off axis, the larger the angle of the cone. See "The Laser Cookbook" by Gordon McComb.

 

[Snecho]

By "circle", are you talking about the size of the dot or a literal projection of a circle?