SU1120400A1 - Automatic focusing device - Google Patents

Abstract

AUTOMATIC FOCUSING DEVICE, containing sequential; but an optically coupled radiation source, a first lens, a beam splitter, and a lens with a switching mechanism, as well as a first two-cell photoreceiver optically coupled to the beam splitter, and a second lens and a second two-area photodetector, two differential amplifiers, and the first lens of them are connected to the outputs of the first two-area photodetector, and the inputs of the second are connected to the outputs of the second photodetector, characterized in that, in order to improve the accuracy of the fuk7, By compensating for the influence of the radiation pattern of the radiation source, the first and second summing amplifiers and analog dividers, as well as the third differential amplifier, the inputs of the divisible first and second analog dividers are connected to the outputs of the corresponding differential amplifiers, the deltgl inputs are through () ) summing amplifiers - with the outputs of the first and second two-area photodetectors, and the outputs of the analog dividers through the third differential amplifier with united with the operating mechanism of the lens.

Description

The invention relates to the field of computer technology, in particular, to the technique of optical recording for reproducing information, and can be used in B devices for recording and reproducing video / or audio information on optical media, as well as in the composition of the optical device 3-1 of our device. -Have digital information reproduction.

A device for the creation of radiation is known, which contains and;} radiation, the first beam splitter, a form of information channel and a focus tracking channel for the lens, the tracking channel containing the first lens and a turning mirror, and the information channel - the second lens, the second and third beacon. and two-power photodetector P.

The disadvantage of the device is the dependence work; the defocus sensor from the misalignment of an ontic beam arising due to non-fluctuations of the radiation source, the direction of the radiation source,

The most close to the invention of the gr :: technical essence and achievable: the result is an automatic focusing device, containing a series of O; tic sz zanly source ipucheni. the first lens, the beam splitter and .iv with and with the 1st mechanism of displacement, as well as optically engaged; g; with the sprint divide of the first DExxIOlda. photo receiver and optically coupled with a beam splitter and a second lens and a second photodetector, two differential amplifiers, the input of the first kkhh connected to the outputs of the first two-continuous photodetector, and the inputs of the second output terminal of the second phototransfer;

The only known device: TWA is the dependence of the output signal of a first-time differential differential amplifier, which is an OUTPUT signal-3 sensor of the auto-amplifying system, on the drift of the frame; and, 1, the power of the source and; joking. since r; when the axis of the radiation source is changed, even: three, precise focusing of the beam on the carrier is informed, and the signal of the datacard appears from the zero, i.e. prk

of works; ai4 from the regulation system introduces 1: defocus, compensate for. change in the signal of the sensor 1rokkhod 1II or or fluctuations of the bottom I; .4i if-5b nap;: 1ar ;; e1 is;

Tse.t: -. Y H oGj-jeTefi:; I in; shets tovi iJiCHHe TOHiioci-n photogrowing by -compR1; ag, in; in; and neither) L octua ;; s; i; -iа: pa-isbi of the directivity of the source L / C,

Goal Achievement of te ;, that in the VCT the automatic focusing, spd, str1, its poleedovatovat-plu optically sls.1e radiation source, lens; a beam splitter and a lens .. 1SG1s; r1 itel ";; M mechanism of displacement, also optically connected ;; l (GOO; 1deto1Ei:; and the first two-way photodynamic, optically and optically; splitters second lens n the second dzhushshadadn1 th photodetector., two differential amplifiers l, and the inputs of the first of them are connected to the outputs - the first two-way photodetector 1nik, and the second, you are the second - with B; lhsdam, -1 E-gogp pho -; opt} and (; minik 5 vnsdsl, iJ and the second summarize 1: 1;; :: force-t-el and anal:; g-svye.eliteli, so the third bottom of the ncialm v-r-1I-gel, entrance delimst of the first to analogue divisors with G | ed11) Lena with outputs corresponding to) g; their d - ((kb |; xncill | Gyp amplifiers, the inputs of the small cell through the corresponding gum; -guide1; hy e amplification n - with outputs of the first and second two-stage photo-holders in 5 and outputs analog of the digital dividers through: the third differential-1; 1 - the amplifier has connection with the gel mechangism of the transceiver: and the object -j,

The device contains a source; radiation, first lens 2, lens 3; HocHTcyib 4 information, the second 5s-gadelitele,: n; nz 6, the first two-way CSCH photoelectric camera / s feelings TjibKbiMH: shoi (henchmen / a to 7i: J-IMHU 3 times; ate between n; -; m, the second one; .zdgyy photo-opriem ik 9 with chuvs-tz:; - 5telbtvbiN-M Tzadki 9a and 9o and line 10 p-a del and meyuu kimk, Btor (zy and third. differentiation-: 5 {Ie amplifiers I - -I 3 5 first and second summing u forces and te and 14 y, 15, first and second a (first,; and both 16 and 17, the first displacement actuator of the lens. The device works as follows. The radiation of the source 1 passes the lens 2, reflects The splitter is focused by the second lens 6 on the sensitive areas 9a and 96 of the two-area photodetector 9 with the dividing line 10, and the part of the radiation passing the beam splitter is focused by the lens 3 on the sensitive surface of the information carrier 4. Reflecting from the carrier, the radiation passes the lens 3 a second time, and being reflected from the beam splitter 5, it falls on the sensitive areas 7a and 76 of the two-area photodetector 7. Offset dy, the beam axis in the plane of the two-area photodetector in the direction perpendicular to the section line 8 between its parts depend both on the change in defocusing of the lens and on the fluctuation oi of the axis of the radiation pattern (the radiation source pattern), which can be written as Y (lk, di where K is the coefficient determining the dependence of the beam axis displacement on the defocusing U, which determines the dependence of the displacement on the drift of the axis of the DN. The output signal of the differential amplifier 1 (Ugjj,,), which produces a signal proportional to the difference in the photocurrent of parts 7a and 76 of the photodetector 7, is proportional to the offset of the beam axis relative to the separation line, the coefficient taking into account the power loss on the optical elements, the reflection factor of the splitter 5 and the carrier 4, the sensitivity of the photodetector 7; the power of the radiation source beam, the output signal of summing amplifier 14 does not depend on the displacement of the beam and is proportional to the power incident on the photodetector and „KjP. The output signal of the analog divider 16 is proportional to the displacement and does not depend on the power and - K 16 - 16 u K (g, is the gain factor of the analog divider 16. The beam offset d (in the plane of the photodetector 9 depends only on the fluctuation of the DN source K, da. By analogy with the previous output signal of the summing amplifier 15 does not depend on the beam displacement and is proportional to the power incident on the photodetector 9. The output signal C2 of the differential amplifier 12 is equal to 12 j — the coefficient taking into account the optical power density on the optical elements; divider 5 and photodetector sensitivity 9. Given (4), (7), as well as (I) and. (5) for the output signal of the differential amplifier 13, which generates the difference signal of analog dividers .1 7 and 18, you can write U , .K, K dй -K K2dot-K K do6 (9) whence when choosing the gain factors of analog dividers according to the condition b we get and, i.e. the output signal of the differential amplifier 13 depends only on the defocus of the lens and does not depend on fluctuation DN axis of the source of study. Thus, the resulting ascent focusing due to out-of-flatness or axial beating of the nose leads to the appearance of a signal and the output of the differential amplifier 13, which is proportional to

defocusing 5 which is uggshl. ispolitelSch) 1g-1 by the mechanism 8, moving the lens in the direction that compensates for defocusing, and in the course of work of the fluke-v chi ocsi DN source -; nick to the same hryvnyyd1d 1 to the same; The output of & x with :: - to an о in at a lot of deposits /: it 16 k / th e changes their signal-sig.a: 1g: k does not affect the operation of the system a:; somatic focusing,

The introduction of analog de-Itayas (and 17, ensuring the independence of signals from optical MotiHocTb, k; it is necessary because the reflection coefficient wears. R; 4 {Formation can vary 3 for example, depending on the reshins the work of the recording device: when the carrier is detected, the carrier has a reflection factor, and, if information is available, it is different, therefore, to ensure the system operation: 1, the signal transmission coefficients on both sources ;;: and: r-; (,) :; .С у-: ilite: 1IK} iie: i a smg:; (ijui ivJec; oft power, fasting, etc. f (U; -o1C) iom1shki,: 1 - / stooys.ke ai thematic f / - y: iitii M,: ic s ;; depot ::.; arg 6; in qyg: -, gigroportsionl;;. .: - ::;:;:;;; 3. I: enik, FOR uggli: yd: al ;; :: ola fosloguggy LN; For ka: l; l; - blyd normalgngo funk: Lh .;,:; ag1. l: dd holim :; obes: furnace: 1a; next, the source system is a single source;,:. - iij-iocKo :: fb photodetector 7

-s-l .; l,; (lily lepi - flat; stol 1111;;; - LIKP h. This is the condition P of the FLOOR: l:::; oo 1 with GS715uk) Bi: i: i6opo: -: fiapa -.-ro: - 1KGGL .. h and p, ;; is the distance from the ling (mg lllllight photoprints; emnik 9 and

 2, Lly: l: cm conditions foL; HHa. h, | p: l: 1me 3p1 rays in the photo -: Reem .. hlch 7 and 9; provides ide: i:. 3 a: lgsim (zstey ihodnn.); l; als1; dlifferential g usiL: I1e.e she

and from the .ManreifHfi axis of the onion otio: / g.: l: o Lt.Mugl R. calcult between mellalt w. ; -O1 namelml-: ov large range -1 i; icr n IK a.

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Claims (1)

AUTOMATIC DEVICE. FOCUSING comprising a follower-but optically coupled with the source of radiation iz ^1, a first lens, a beam splitter and a lens with the actuator displacement, and optically coupled with the beam splitter and the first dvuhgshoschadny photodetector optically coupled to each other and the second beam splitter and a second lens dvuhploschadny photodetector, two differential amplifier, wherein the first inputs of which are connected to outputs of the first photodetector dvuhpposchad ¹ Nogo and second inputs - outputs a second photoreceiver nick, wherein h o, in order to increase the accuracy of focus by compensating for the influence of fluctuation pattern of the radiation source, it entered the first and second summing amplifiers and analog Suitable divisors, and a third differential amplifier, the inputs of the dividend of the first and second analog dividers are connected to the outputs of the corresponding differential boiling ¹ amplifiers, the inputs of the divider through the corresponding summing amplifiers - with the outputs of the first and second two-area photodetectors, and the outputs of analog dividers through the third diff A potential amplifier is connected to the actuator for moving objects. I I 20 -, 00 i