How does an F theta lens work?
How does an F theta lens work?
F-theta lenses are designed to focus a laser beam onto a planar image plane. They are often used in a scanning system with two galvanometer mirrors. One mirror is responsible for beam deflection in one direction and the second one for the perpendicular direction.
What does F theta mean?
where L is the diagonal of the square scan field, θ is the maximum deflection angle in radians, and again f is the effective focal length of the lens. By maximizing θ, the focal length can be minimized in a system.
What is focal length of scan lens?
F-Theta Scan Lenses
| Item # | FTH100-1064 | FTH160-1064 |
|---|---|---|
| Effective Focal Length (EFL) | 100 mm | 160 mm |
| Scan Angle (Max) | ±28° | ±28° |
| Scan Length (Max) | 98 mm | 156.4 mm |
| Scan Field (Max) | 70 mm x 70 mm | 110.6 mm x 110.6 mm |
What is a scan lens?
Scanning lenses are constructed to produce a focused spot in a flat field, the position of the spot being proportional to the focal length (f) of the lens and the angle (theta) of the beam entering the lens, giving them the name f-theta lenses. Ideally the size of the focused spot is constant throughout the field.
How do I choose a telecentric lens?
Choosing the right telecentric lens is easy: we must find the magnification under which the image fit the sensor. Example. We need to measure the geometrical feature of a mechanical part (nut) using a telecentric lens and a 2048 x 2048, 5.5 µm sensor.
What is scan lens?
Which lens is used in scanner?
The lens of high-end 35 mm Nikon film scanners like the Coolscan 4000 and 5000 is reported to be a 38 mm f/2. It is designed for use with a thin glass plate covering the sensor, and the specified optical resolution of these scanners is 4000 dpi as well.
How does the Fresnel effect work?
This type of shading is inspired by the Fresnel effect, which describes the amount of reflection and refraction of light on a surface in relation to the viewing angle. A flatter viewing angle on a surface increases the amount of light that is reflected, resulting in the surface appear- ing brighter when lighted (Fig.
What are telecentric lens used for?
Telecentric lenses are often used for precision optical two-dimensional measurements or reproduction and other applications that are sensitive to the image magnification or the angle of incidence of light.
