Liquid nitriding is a subcritical surface enhancement process with one of the longest track records of success of any case hardening technology.

Magnificationformula Biology

DLC coating hardness can range from 2500 HV to 4500 HV depending on the type of DLC coating including the choice of underlayer.

According to this formula, the smaller the F number (brighter) of lens, the smaller the pixel pitch of sensor and the larger the optical magnification (enlargement) the narrower the depth of field. Incidentally, “depth of field DoFi” is applicable to short object distance case such as machine vision, however, the depth is significantly different between the front side and the back side of the object in long object distance case such as surveillance camera. In this case, “depth of field DoFi” is found with “depth of focus DoFo” and “Newton’s lens formula”3.

Magnificationformula for mirror

CERTESS® CARBON is a tradename of HEF Group for DLC coatings. Depending on your application, there are different options that can be provided within the family of CERTESS® CARBON coatings. Some of these include:

“Distance of distinct vision” is the distance between eyes and object in which we can see the object clearly without tension or fatigue. It is supposed to be 250 mm (=4 diopter) since ancient age. The reason that 25 – 30 cm distance is recommended for book reading is also distinct vision distance. By the way, elasticity and adjustability of eye lens is getting lower as aging and object can hardly be seen unless locating it further than distance of distinct vision. This is so called Presbyopia.

DLC coatings are deposited at relatively low temperatures below 200°C. HEF’s specific deposition technology allows us to deposit these coatings at around 170°C. With our plasma enhancement technology, HEF is able to deposit at such low temperatures to ensure no distortion or change in core properties of the component being coated. Thus, precision components with tight dimensional tolerances can be DLC coated without any concerns.

”Longitudinal magnification α” is a ratio of “minute transfer amount ⊿x’” of image against “minute transfer amount ⊿x” of object along optical axis. In other words, it means sensitivity on focus out.

Magnification ofconvexlensis positive or negative

Ratio of length change by optical system is called “magnification”. Taking lenses used in photo or machine vision are included in “Image forming optical system”. In the term of “magnification m”, there are “lateral Magnification β” and “longitudinal magnification α”. β indicates ratio in size of concerned object and image while α indicates ratio in optical axis. These will be explained in next chapter. In case of magnification in size, it is called “equal magnification”, “1-fold magnification” or “1x” if image and object are the same in size. The value is more than1 such as “2-fold magnification”, “2 power” or “2x” in case of expansion while it is less than 1 such as “0.5-fold magnification” or “0.5x” in case of shrinking. Furthermore, the sign of magnification (Lateral magnification, β) is negative (-: minus) as image is usually inverted.

In the machine vision field, optical magnification is important to select taking lens or to consider optical system. However, it is not well known and sometimes confused that magnification has a meaning other than imaging magnification, generally known, which indicates size ratio of object and image. We would like to explain, here, a concept and applications of magnification clearly.

Magnification ofconvexlens

Therefore, longitudinal magnification α is the square of lateral magnification β in case amount of object movement is comparatively small.

PVD coatings involve the deposition of thin (2-10 microns; 0.0001" – 0.0004") films on the surface of tools and components.

Magnification of a lensformula

DLC coatings are generally applied after a PVD underlayer such as Ti, Cr, CrN or WCC or a combination of them has first been deposited on the component surface. The selection of the underlayer depends on various factors such as hardness of the component surface (substrate), bonding characteristics with the substrate, load bearing requirements of the application, etc. The choice of underlayer is determined case by case primarily based on the application and performance requirements.

Let “permissible circle of confusion CoC” be larger one of “pixel pitch Ppix” or “airy disk diameter Dairy”. “Depth of field DoFi” can be found with dividing “depth of focus DoFo” by “longitudinal magnification α”.

Lensformula

DLC coatings are used for many of the applications that have been highlighted for PVD coatings, in general – except for cutting tools which are exposed to high operating temperatures. DLC coatings are especially useful where a combination of both wear and friction reduction is required. DLC coatings also offer a cosmetically pleasing black finish. Typical applications include:

As taking lens in image forming optical system shoots real image, “Lateral magnification β”, size ratio, can be calculated by direct measurement of object and image. On the other hand, in case of tele scope and binoculars, real image made by objective lens is seen as virtual image through eyepiece. They are in a special optical system as incident light and outgoing light is parallel to optical axis. In this optical system, called “afocal system” or “no focus optical system”, “angular magnification γ”, which is a ratio of inclination angle u’ between light from object and optical axis to inclination angle u’between light to image and optical axis, is used for magnification m.1

This means that object can be seen in the same size as if observer comes close to it in 1/γ distance. As magnification gets bigger, the structure becomes bigger as well as viewable range becomes narrower and image becomes darker because “exit pupil” becomes smaller. Binoculars with specifications of 6 to 8-foldmagnification and 30 – 42 mm in diameter2 is manly used for bird watching for its portability. While that with specifications of 7 – 18-foldmagnification and 50 – 70 mm in diameter is mainly used for star watching. Binoculars of high magnification are usually used with tripod to mount. Meanwhile, that of around 10-foldmagnification with stabilizing mechanism is getting popular for theater use recently. Exit pupil is calculated with formula as “lens diameter ÷ magnification”, and it get hard to see if it is smaller than eye pupil. Because of this reason, binoculars with exit pupil of more than 3 mm are used in daytime, and that with more than 5 mm is used in nighttime or dark place. Binoculars with compact size and high magnification are sold as popular type. Due to smaller exit pupil, their view might be dark or visibility might be lost by eye movement (black out). Careful use is required for these types of binoculars.

Coefficient of friction is a system property. It is generally the ratio of the frictional force to the normal force when two bodies interact with each other. Deposition of DLC coatings helps with friction reduction of the system for applications involving smooth, interacting surfaces. Lubrication plays a key role in this property as well. Typical friction coefficient range for such systems with DLC coated surfaces can be around 0.1 to 0.2 in a dry-condition and less than 0.1 in a lubricated condition.

Magnification of a lenscalculator

Magnifying glass is also in optical system to see virtual image. Magnification m can be calculated as a ratio of “distance of distinct vision of 250 mm” and “focal length of f”.

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In case of general object distance in machine vision, the formula can be easily found with above mentioned “longitudinal magnification α” because “depth of field DoFi” is “depth of focus DoFo” which is shifted to object side through lens.

Magnificationformula forlensin termsoffocal length

DLC coatings are deposited using a Plasma Assisted Chemical Vapor Deposition (PACVD) method. Unlike PVD method that involves physically depositing the solid target material source on the component surface, PACVD on the other hand involves a precursor gas source (hydrocarbon) that is broken down into carbon and hydrogen atoms in plasma, deposited as DLC on the component surface in an amorphous fashion.

HEF bushings are recognized worldwide for their excellent frictional and anti-seizure properties, and ability to withstand high loads.

In case of zoom lens, used in digital camera or video camera, magnification of 3x, 6x or 30x are indicated. This is called “zoom ratio” and it means ratio between focal length of longer side (tele side) and shorter side (wide side). For example, zoom ratio of zoom lens which focal length can be adjusted 8 – 80 mm is 10x.

DLC stands for Diamond-Like Carbon. This is a special family of thin-film coatings that provide the high hardness like diamond (due to its tetragonal structure) and low lubricity like graphite (due to its hexagonal structure). DLC though, is amorphous in nature i.e. it does not have a crystal structure, however, offers combined advantages in spite of its overall random arrangement of carbon atoms.

Total coating thickness including the underlayer is uniform and generally in the range of 2 to 5 microns. The exact coating thickness within this range is determined based on the application and performance requirement.

Yes. DLC coating can be removed or stripped if required. While the DLC layer can be removed within the same coating chamber using a reactive plasma-based process, removal of the PVD underlayer(s) requires components to be immersed in a chemical solution for a certain time period. The components may require additional polishing before recoating. This is generally discussed with the customer on a case-by-case basis. HEF has the capabilities to offer these services, if required.