Crossword clues for pinhole
pinhole
Longman Dictionary of Contemporary English
Wiktionary
alt. A small hole, of a size that could have been made by a pin n. A small hole, of a size that could have been made by a pin
WordNet
n. a small puncture that might have been made by a pin
Wikipedia
Pinhole may refer to:
-
Pinhole (optics), a small hole used as an optical aperture
- Pinhole camera, a camera that uses a pinhole to form an image instead of a lens
- Pinhole glasses, a visual aid
- Pinhole occluder, a medical device used in measuring visual acuity
- Pinhole (band), a rock band from Liverpool, England, later to become The Dead 60s
- Pinhole (song), a song by Japanese rock band Ogre You Asshole
- Firewall pinhole, in computer networking, a port that is opened through a firewall for a particular application
A pinhole is a small circular hole, as could be made with the point of a pin. In optics, pinholes with diameter between a few micrometers and a hundred micrometers are used as apertures in optical systems. Pinholes are commonly used to spatially filter a beam (such as a laser beam), where the small pinhole acts as a low-pass filter for spatial frequencies in the image plane of the beam.
A small pinhole can act as a lens, focusing light. This effect is used in pinhole cameras. This effect is also used in pinhole occluders, which are used by ophthalmologists, orthoptists and optometrists to test visual acuity. The same principle has also been applied as an alternative to corrective lenses: a screen of pinholes is mounted on an eyeglass frame and worn as pinhole glasses.
A pinhole is a small hole, usually made by pressing a thin, pointed object such as a pin through an easily penetrated material such as a fabric or a very thin layer of metal. Similar holes made by other means are also often called pinholes. Pinholes may be intentionally made for various reasons. For example, in optics pinholes are used as apertures to select certain rays of light. This is used in pinhole cameras to form an image without the use of a lens. Pinholes on produce packaging have been used to control the atmosphere and relative humidity within the packaging.
In many fields, however, pinholes are a harmful and unwanted side-effect of manufacturing processes. For example, in the assembly of microcircuits, pinholes in the dielectric insulator layer coating the circuit can cause the circuit to fail. Therefore, "[t]o avoid pinholes that might protrude through the entire thickness of the dielectric layer, it is a common practice to screen several layers of dielectric with drying and firing after each screening", thereby preventing the pinholes from becoming continuous.
Usage examples of "pinhole".
Behind the plane where the interference pattern forms, Afshar places a lens that forms an image of each pinhole at a second plane.
Then Afshar measures the difference in the light received at the pinhole images with and without the wires in place.
In fact the Misses Graves had already arrived when she left, and no sooner had she gone when Miss Pinhole, who did a lot of dressmaking for Miss Fielding, rang the bell.
Pinhole penetrations of the black object by micrometeorites should not be much of a problem, since the occulter could be designed to self-seal around small penetrations.
Moreover, even if the occulter developed many pinholes, the diffraction effects would spread the penetrating light over an area much larger than the images of interest, reducing its effect.
For fifty tals I let three units of light shine full in the pinhole, then one unit for one xat, and for twenty-five tals nine units.
The wood was covered in pinholes and here and there rusted metal pins still stuck out of it, attaching blackened shards which were all that remained of some covering material.
The lasers were meant to implode a deuterium pellet at the shell's heart and direct the resulting plasma down a pinhole pathway aligned with the axis of the gun barrel.
The Oldest One was like a hydraulic engineer transfixed at the base of a hydroelectric dam, watching a thin needle of water spurt hundreds of meters into the air, out of an almost invisible pinhole.
There was nothing wrong with the idea of a pinhole camera eye, whose retina was composed of olfactory nerve endings rather than the rods and cones of photosensitive organs.
They photograph through perforations : half a dozen pinholes and the lens can see perfectly.
Other crustaceans have a compound eye like insects (really a bank of lots of tiny eyes), while other molluscs, as we have seen, have a lensed camera-eye like ours, or a pinhole camera-eye.
It looks at the stream of frames (individual still images) coming from the pinhole camera and notices that, although the total amount of data in those frames is rather large, the difference from one frame to the next is tiny.
I ask each of my students to make a pinhole camera like this, and to experiment with it.
It seemed like she was straining to see through these narrow apertures in order to magnify her field of view--much in the manner of a pinhole camera.