Glossary
ANSI
Acronym for American National Standards Institute. An organization that generates the ANSI Z136.1 Standard for the Safe Use of Lasers and other safety standards for laser users.
Boresight
The boresight is a measure of the deviation of the optical axis of the laser beam with respect to the mechanical axis of the laser housing. All Lasiris™ lasers are boresighted to less than 3 mrad (~0.17°) at a distance of 1 meters.
CCD
Acronym for Charge-Coupled Device. In common terms, it's the semiconductor chip that is used to collect light and convert it into a digital image. The conversion process involves grabbing the collected light from small sections of the chip in a continuous fashion similar to a television screen.
CDRH
Acronym for Center for Devices and Radiological Health. A regulatory organization that publishes legal regulations for medical devices, including laser products, applicable in the U.S.
Collimation
The process by which a divergent beam of radiation is converted to a parallel beam. A diode laser focused at more than ~115 cm (~45 inches) is said to be "collimated" for all practical purposes.
CW
Acronym for Continuous Wave. A term used to describe the output of a laser emitting radiation continuously rather than in short bursts. See Pulsing and power Adjustment for opposite definition.
Depth-of-Field
The depth-of-field (DOF) is defined as the distance through which satisfactory definition can be maintained when a lens is in focus at a particular distance. In other words, this value lets the user know the range over which there will be a significant difference in line thickness. There is a general agreement that "satisfactory definition" is maintained as long as the image size remains smaller than 1.4 times its smallest size. This distance is also called the Rayleigh range. The DOF is therefore equal to twice the Rayleigh range of the focusing system.
Sideview of laser beam. Beyond the Depth-of-Field,
a laser pattern will appear out-of-focus.
Fan Angle
The fan angle F.A. is the angular spread of the laser beam, defined by the equation
FA = 2 Arctan (L/2D)
where L is the length of the line (or pattern) required to illuminate the target and D is the distance between the laser projector and the target. Alternatively, to calculate the length of the line L produced at a projection distance D at a set fan angle F.A., the following formula is applicable:
L = 2D tan (FA/2)
Focus
The focus is the point on the optical axis of a lens or optical system to which parallel rays will converge. All Lasiris single line, multiple line and pattern projectors are focusable, (except for the factory-set LC series lasers), allowing the adjustment of the line thickness (or focus) at the desired projection distance. The projected line has a non-gaussian intensity distribution along its length but remains gaussian across the width. The line thickness is always measured at the 1/e2 points of the gaussian thickness profile. The 1/e2 points correspond to the points where the intensity is approximately 13.9% of the peak intensity (100%).
Most focusable Lasiris lasers come with our unique C-Thru wrench, specially designed to make focus adjustment easy. The focus can be set in three easy steps. The pattern generating head from the laser projector must first be removed; then the focus is adjusted with the C-Thru wrench, and finally, the head is put back in its original place.
Gaussian
Visit our What is a Non-Gaussian Distribution? page.
IEC
Acronym for International Electrotechnical Commission. An organization that publishes the IEC 60825-1 laser safety standard.
Infrared (IR.)
The invisible portion of the electromagnetic spectrum that lies between 0.75 and 1000 µm. All IR. Lasiris™ lasers emit in the region of 780 nm-1550 nm (near IR.).
Interbeam Angle
The interbeam angle is the angular separation between any two lines, dots, or circles projected by our lasers. When specifying a multiple line pattern, it is important to know the desired distance between the lines at a fixed distance. The inter-beam angle is given by the formula:
q = sin -1 (Λ/D)
where D is the period of the diffraction grating, l is the wavelength and q is the interbeam angle.
5-line Laser with diffraction grating (pattern-generator)
Modulation
A change in the output level generated by a change in supplied voltage.
Nanometer
A unit of length in the metric system equal to 10-9 meter.
Non-Gaussian
Visit our What is a Non-Gaussian Distribution? page.
Off-Axis Laser
Laser that is not perpendicular to the surface on which it is projecting laser light. (details)
Spatial Filter
A spatial filter enables a laser beam to be filtered such that noise around the beam is reduced. A beam with a spatial filter will appear "cleaner", with less imperfections.
The spatial filter consists of a focusing lens and a pinhole placed at the focus point of that lens. The beam goes through the lens, gets focused at the pinhole, and the parts of the beam that have diverged from the focus point due to imperfections in the lens or contamination will not go through the pinhole. Optical noise around the beam is thus filtered out.
Structured Light
A term used in Machine Vision applications to describe any light source that projects a known geometric distribution of light. Visit What is Stuctured Light?
Visible
The region of the electromagnetic spectrum which is visible by the human eye. Light in the visible region falls between 400-700 nm.
Wavelength
Electromagnetic energy is transmitted in the form of a sinusoidal wave.
The wavelength is the physical distance covered by one cycle of this wave.
Wavelength is inversely proportional to the frequency.