USB microscope
Encyclopedia
A USB microscope is a low-powered digital microscope
which connects to a computer, normally via a USB port. They are widely available at low cost commercially. In essence USB microscopes are a webcam
with a high-powered macro lens and generally do not use transillumination
but rely on incident light instead. As the camera attaches directly to the USB port of a computer eyepieces are not required and the images are shown directly on the monitor. They offer modest magnifications (up to about 200×) without the need to use eyepieces at very low cost, and illumination is in-built.
light) can be used to highlight features of interest in the object. They generally offer a large depth of field
at the cost of a smaller numerical aperture and so amount of light collected.
USB microscopes are most useful when examining flat objects such as coin
s, printed circuit board
s, or documents such as banknote
s. Their use is generally similar to that of stereo microscope
s. USB microscopes offer the great advantage of being much less bulky than a conventional stereo microscope so can be used in the field, attached to a laptop computer.
Digital microscope
A digital microscope is a variation of a traditional optical microscope that uses optics and a charge-coupled device camera to output a digital image to a monitor, sometimes by means of software running on a computer. A digital microscope differs from an optical microscope in that there is no...
which connects to a computer, normally via a USB port. They are widely available at low cost commercially. In essence USB microscopes are a webcam
Webcam
A webcam is a video camera that feeds its images in real time to a computer or computer network, often via USB, ethernet, or Wi-Fi.Their most popular use is the establishment of video links, permitting computers to act as videophones or videoconference stations. This common use as a video camera...
with a high-powered macro lens and generally do not use transillumination
Transillumination
Transillumination is the technique of sample illumination by transmission of light through the sample. Transillumination is used in a variety of methods of imaging.-Microscopy:...
but rely on incident light instead. As the camera attaches directly to the USB port of a computer eyepieces are not required and the images are shown directly on the monitor. They offer modest magnifications (up to about 200×) without the need to use eyepieces at very low cost, and illumination is in-built.
Usage
Images can be recorded and stored similar to a webcam on the computer. The camera is usually fitted with a light source, although extra sources (such as a fiber-opticOptical fiber
An optical fiber is a flexible, transparent fiber made of a pure glass not much wider than a human hair. It functions as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. The field of applied science and engineering concerned with the design and application of...
light) can be used to highlight features of interest in the object. They generally offer a large depth of field
Depth of field
In optics, particularly as it relates to film and photography, depth of field is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image...
at the cost of a smaller numerical aperture and so amount of light collected.
USB microscopes are most useful when examining flat objects such as coin
Coin
A coin is a piece of hard material that is standardized in weight, is produced in large quantities in order to facilitate trade, and primarily can be used as a legal tender token for commerce in the designated country, region, or territory....
s, printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
s, or documents such as banknote
Banknote
A banknote is a kind of negotiable instrument, a promissory note made by a bank payable to the bearer on demand, used as money, and in many jurisdictions is legal tender. In addition to coins, banknotes make up the cash or bearer forms of all modern fiat money...
s. Their use is generally similar to that of stereo microscope
Stereo microscope
The stereo or dissecting microscope is an optical microscope variant designed for low magnification observation or a sample using incident light illumination rather than transillumination. It uses two separate optical paths with two objectives and two eyepieces to provide slightly different viewing...
s. USB microscopes offer the great advantage of being much less bulky than a conventional stereo microscope so can be used in the field, attached to a laptop computer.