The article introduced a kind to be based on laser interference to measure grow and the arm of hard disk flexibility of trigonometry sine principle curves angle to survey a system, this system changes the measurement of angle the displacement of the lines that to measure interference the optical path difference in smooth road changes, undertake handling to interfering stripe through corresponding circuit, realized the measurement to old point of view thereby. With before similar system photograph is compared, this system has a structure simple, measure precision the tall, range that measure part is big, easily the characteristic such as digitlization. 1, attitude of static state of arm of flexibility of magnetic head of introductive hard disk is measured is hard disk the crucial working procedure in producing a course, does the main measurement technique on the tradition have: ? そ of arm spread of grave of Shan of obstruct of Pu of lift up of of of つ of mildew arm spread is embedded however if sensor of type of bar of synchronized of capacitance type angle and angular displacement sensor, induction, magnetism measures horn to wait a moment,? of Tun of beach of humerus of ⒙ of dispute a huge legendary turtle uses sensor of electromagnetism of electromagnetism principle job. But, below some circumstances, traditional measurement technique and technology undertake to old point of view or angular displacement high accuracy is measured cannot satisfy a requirement well. Well-known, very wide application already was won in interfering a technology to be measured in nicety, especially the development of the occurrence of laser and laser technology, the application in making this technology is measured in nicety was broken through before the limitation of the illuminant with because shortage is high good sex of brightness, monochromatic, promoted the interferometer application in measure greatly, one of main measures that the nicety in making use light-wave to interfere a technology to undertake metrical making scientific research and production gradually thereby measures. Moreover, because chip part is very small, can be out of shape below the action that contacts force and produce very big measurement error, can undertake detecting with blame contact method only so. Angle can express those who be length to compare, the change of length can interfere the variation that stripe counts to express with laser, accordingly, the blame contact that the article put forward a kind to be based on laser interference to measure senior technology surveys horny system of stretch to hard disk magnetic head arm curve a circumstance to undertake metrical, the system is formed and measure a principle to undertake corresponding analysis to its. 2, the system that systematic introduction uses laser to interfere a technology to measure angle of bend to spend is very much. Popularly, this kind of system basically reachs signal to handle by detector of laser, interferometer, photoelectricity circuit and show the system that print is comprised, graph the 1 compositive principle block diagram that is this kind of system. 3, measure a principle this angle interferometer is the instrument that uses laser interference to measure displacement and trigonometry sine principle to measure point of view. If the graph is shown 2 times, the movable type of classics of laser light beam that laser １ gives out changes illuminator to 2 reflex to prismatic implement 3, stimulate beam of light to be divided two. Shoot along smooth road A all the way to referenced lens 5, all the way classics of B of edge smooth road 5 prism 4 change direction, shoot to target pyramid prism 6, next these two bundles of light are returned by former road prismatic implement 3 generate interference. Pyramid prism 5, 6 be secured to be in rotate workbench 7 on. When measuring, target lens and couplet of firm of the target that be measured, referenced lens is fixed do not move, when target lens moves along with the object that be measured, the optical path difference of two beam of light produces change namely, interference stripe also will produce light and shade to change alternately. If use photoelectricity detector to receive, when the object that be measured is mobile, circuit of the class after photoelectricity detector will receive the shift of stripe and be being passed changes his the pulse that it is report, be opposite through reversible computation system pulse computation in order to achieve the goal of metric angle. When Nextpage is measured, classics of a bundle of laser is prismatic implement 3 be become two bundles by cent, lens of their classics reference 5 with target lens 6 hind return along former road, nodding O place to encounter afresh prismatically, criterion two bundles of smooth optical path difference are Δ 2 N of 1 ＝ (L2-L1) in type, n is airy refractive index, l2 is target lens the 6 distances that arrive to nod O prismatically, l1 is referenced lens the 5 distances that arrive to nod O prismatically. When measuring an end, target lens 6 had moved after H, be in the position of 6 ′ . Right now the optical path difference of two beam of light is Δ 2 N of 2 ＝ (L2 ＋ H - L1) １ of Δ of 2 NH ＋ is measuring ＝ to begin and end this paragraph of time in, the Δ of ＝ of Δ of metabolic quantity D of optical path difference 2 - 2 NH of Δ １ ＝ optical path difference every change a wavelengh, interference stripe changes alternately with respect to light and shade, the Δ of D of ＝ of K of frequency of interference stripe change that in measuring a process, answers relatively with D Δ / 0 ＝ of λ in 0 type of 2 NH/ λ , λ 0 for wavelengh of laser light-wave center. After measures so that interfere stripe metabolic frequency K, can by on type gets H of the length that be measured. In be measured actually, use interference stripe counting method, measure make in the begining tally buy 0, measure the indication of the tally when the end is the stripe that answers relatively with H of the length that be measured to count K namely. But on type is written for λ of H ＝ K / in 2 type, 0 ／ of λ ＝ λ N, λ is laser light-wave the wavelengh in air. Be like foregone target lens radius R, can beg a ／ of ArcsinH of ＝ of α of A of the horn that be measured according to trigonometry sine relation in R type, r is prism radius. The measurement of this kind of device limits can amount to 95 ° , measure precision to be able to amount to ± 0.
3 ″ . Because we want the angle of bend of arm of metrical flexibility of hard disk magnetic head to spend,be more than 95 degrees, use the means that measures its supplementary angle so, final measurement R of ／ of =180º- ArcsinH of eventuate α ′ . 4, the main factor that measures precision to affect this system to measure precision has: Wave of valid area, laser measures pyramid prism longly of refractive index of error, air measure an error to wait, one brief analysis is done with respect to this a few respects respectively below. It is the valid area of pyramid prism. By the graph 2 knowable, pyramid prism 5, the 6 installation on workbench can produce an error, target lens 6 also can produce athletic error when roll, the heat that causes workbench as a result of the change of environmental temperature in working process goes up cold shrink etc, can bring about incident beam of light and pyramid prism not perpendicular, cause thereby measure an error. Measure precision to rise, when installing pyramid prism, perhaps adjusting prismatic implement when the position, want to accomplish exact location, accomplish incident light and prism as far as possible perpendicular; at the same time, maintain as far as possible measure environmental constant temperature, prevent heat to bilge cold shrink, also can reduce this kind of error. 2 it is laser wavelengh. The expression that measures an outcome by this system that measure part is knowable, laser wavelengh has very apparent effect to measuring result precision, measure precision to rise, we can consider to use firm frequency in laser illuminant place implement, raise laser to output the stability of frequency, reduce the error that laser wavelengh measures thereby. 3 it is air refractive index. The influence of air refractive index is any measurement the system is inevitable, because this needs to determine accurately the refractive index of ambient air, decrease right all round the generation that airy disturbs to swift current in order to decrease, avoid as far as possible from this and the become shake and causes metric error that interferes stripe. Integrated above each element, pass experimental test and verify, the measurement of this system that measure part precision can amount to ± 0.
3 ″ , angle of bend of arm of flexibility of magnetic head of basic contented hard disk spends horny precision to ask. 5, theory of interference of epilogue application laser measured a principle to undertake an analysis to laser angle, the attitude of static state of arm of flexibility of hard disk magnetic head that put forward a kind to be based on laser interference to measure chief principle surveys a system, built stretch arm angle of bend to spend horny mathematical model. CNC Milling