SU90066A1 - Device for automatic focusing - Google Patents

Description

The subject of the invention is a device for aztomatical sharpness in re-inspecting cameras, looking like ohmic resistances mounted on a camera's CToiii e.

Mechanical inversors used for this purpose: lever-angular, curved, tape, rack-and-pinion, etc. are very cumbersome, complex, difficult to apply) and focus-focus lenses and can be used only in a limited interval of shooting scales.

The proposed device, which represents co6oij electric inverse, eliminates the indicated drawbacks.

FIG. 1 shows the layout of the elements of the device on the front of the camera; in fig. 2-circuit diagram of a device for a camera with a fixed lens stand when solving a formula. in fig. 3- photoelectric ind;: katorkoe device; in fig. 4 - electrical device diagram

for a camera with

fixed CToiJKo ;; Lens when solving

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fng O-electric device layout for a camera with a fixed frosted glass box when solving a formula

--a: in FIG. 6 is an electrical diagram of a device for photo-diarrhea with a fixed frosted glass box when solving the formula Z: -;:. X, -L., - (- 7.

If the proposed device is applied to a reproduction camera with a fixed lens, it can be performed to solve one of the two formulas that determine the relative position of the originator 7, pillar 2, lens 3 and frosted glass box 4 of the reproduction camera 5 (Fig. 1) installed on bed 6: -L- (1)

where: l 1 U l.2 — distance from the planes of the original and the grid-sensitive Glaterial's corresponding to the front and back of the front. ijiOKVcoB obekgiva;

x and x., are the distances from the planes of the original and the photosensitive material, respectively, to the front and rear Heii of the main planes of the lens; f-focus lens distance.

Obviously, x, a l; 2 - l% - {.

Consider a device constructed to solve formula (1).

On the frame 6 of the camera 5 (Fig. 1), two variable ohmic resistances R. and R: J are fixed, the values of which are proportional to the respective distances m and h hg.

The resistances of R., and R ;, are constructed in such a way that - p --- x and g - x ,.

The contact.g is secured on the frosted glass box, and the contact p on the original holder, i.e., is moved along with the 1MT glass box and the original watch holder.

Resistance R. and R ,, are included in the opposite shoulders of the bridge (Fig. 2). The two other arms include equal resistances of the first point of RI and R, the proportional values of the focal length of the lens. To the points a p b connects the source of direct current. An indicator device is connected to the diagonal rd of the bridge. When (or Ifd: TjO), that is, if there is no current in the cd diagonal, the bridge is balanced and the equality is true:

RiR4 R2R: 3a)

The resistances R ,, R. ,, R: i and R are made in the form of tensioned strings, or in the form of a spiral, wound; on the round rod. Resistance bores are proportional. their d. Ri: -; v, l,; R,: s. .-KL, -, kA „where K ,, / i. ,, Az, /t.i- coefficients 11roporg1, ionities (their

size (ohm; mm)

1, and 14 is the length of the resistances K, and R.J in mm;

L and 1.- race t about and p ie by points p /; and hg in mm.

Assuming that l -, -: - / ..% - to - - to.

Then uravpeiiie (:) you can write the following way: 1.1, and ,, ........ ()

Accepted: 1, 14 i

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Pos, -; e substatirovka these values in equation (3), we obtain the formula (). So o6pa30: vi, having seen that it is 11) useful for aiming the camera in sharpness.

Depending on the nostroi principle of the indicator device, there are two possible variants of the EC scheme: 1, the device s: without automatic control and with automatic control.

1) otoapiarata sharpness in the case of the use of the device without automatic control of the axle, 1, 1 is in the following way.

Assume that the camera's main control is a box of 4 MaTOBOio glasses. When the scale of shooting (M- 1: 1) pr-hg -: - f.

When the frosted glass box is mixed manually or by the electric motor by any value (to get a different shooting scale), the balance of the bridge (Fig. 2) is disturbed and the current measured by the indicator in this diagonal is flowing through the diagonal of the bridge cd. The restored balance of the bridge is carried out with the manual movement of the original 7 by hand or with the help of an electric motor (f: 1 d. 1).

When 1; the equations (O or (Z)) indicator shows that there is no current in the diagonal, which means: pointing the camera at sharpness. Orpg can be a driving element;

In the case of uapiiaina with an autolab control, the box, - riiaTOBorri crex.ia (manually or with an iomopido electric motor) entails a violation of the axle bridge (Fig. 2). The current in the fd diagonal diagonal is: it is activated when the device is turned on like; 1 is on; the first is to turn on: the lector of the original drive motor. This, or; ginaloder; spruce, HomileP1, is eq / .: (;; 0 time, K. p liOCCTn impose: ravi; weight of the bridge — and this MOMeiiT is the original electric drive motor / off; ; b;) az: 1o with:.; e: 1e is not a great trouble; ; ::) th (; for za.

In the head: simost 1 from the required thickness: Gapom iiHiiepcopa its parameter is selected:; its costructive design 1e. For example, for more accurate automatic; It is possible to set the alphabet and its status as an indicator, according to the scheme given by it. Oh, and a mixture of a mirror / mirror galvage gauge, including one into the diagonal of the bridge, light elemeiteite o and o, iCiOniiiKa light / 6, which is narrow; a beam of light 1 falling onto a galvanometer mirror. AND; Wild mountain device operates as follows: if there is no current in the rd circuit rd, then z {) kalo 7 galvanometer spreads the iriend cooler beam //. Consequently, the beam reflected from the mirror returns to the light source /: /. In MOMeirr, equilibrium is handled in i3 iepi: the tel bridge due to overpasses another 4 frosted glass boxes in either a side or iii, de ged; 1, and g contact, and a galvanotetra mirror 7 is deflected from the initial position and occupies the position shown in FIG. 3 nupktvrom. In this case

, reflected: from a galvanometer mirror, gets on a photoele; 1ent 5 or .9 depending on the direction of the current in the rd circuit. In the photo - lei1gge, a current arises, which piiii is used to turn on the electric motor of the drive of the original holder. The latter is maintained until the bridge equilibrium is restored and the ray // does not return to its original position. The oripshalder drive motor is turned off - the futoa 1pa 1at is brought into focus.

FIG. 4 shows an electrical circuit of ycTpoiicTBa performed to solve equation (2).

As in the best case: RI id .; K,: AL; R ;; / d .; R, 7Л ... (4)

rivc / b: Ij --- fq Л.,; I.

l, -: hg-.v, -f; one,..: . (five)

The gH q contacts are rigidly connected between each other, on one another and fixed on the frosted glass box. Contact / fixed on the holder on the holder.

i.iii equation 1Uvipenogo 1nogo octa we have:

R, -R, R -, - R ,.

G1stav1sh value of resistance from equations (4) and (5), get i:

f-.V .-. Vi (.V. f)

fU, -;. v,) -. x, .. v ,; f - - and finite, 1but we get Lormula (2)

-1 J L X, X,

Consequently, the device constructed according to this scheme (FIG. 4) provides the thread and the cut.

FIG. 5 shows an electrical circuit of the apparatus for a reproduction camera with a fixed frosted glass box.

Suppose that the vedui |, it is the element of the lens stand and, therefore, the slave is the original, ercate, 1b,

The position of the document holder relative to the frosted glass box is determined by the formulas:

2 - A-1 l2 - a (6)

Z r2f -: - xi-r .л, - a (7),

where: rt is the distance between the main planes of the lens.

In the circuit of FIG. O, by which equation (7) is solved, the sliding contacts g and h are rigidly connected to each other and fixed on the lens stand. The segments hg and on are equal to each other and are equal at that time l,.

The segment pr is equal to l-. The sliding contact is fixed on the orginal holder. When the contacts g and p are displaced with the lens stand by the value v.j, the contact p together with the original holder is shifted by xl, l. To restore balance in the bridge circuit.

FIG. 6 shows the scheme, using KOTopoii, equation (6) is solved. The pins g, q, t move at the same time at the same speed, equal to the speed of the lens pole. Moreover, the segments nt - oq -l ,.

The contact p is fixed on the platen and, to restore the balance of the bridge, always switch 1, in such a way that

hp-.z-xi {-x.

The design of the device depends on the type of camera and the required accuracy of work.

PREAMETE OF THE INVENTION

Device for automatic adjustment and sharpness in renoduction photoannarats, made in the form of OMii4ecKHx resistances, mounted on the stand of the camera, in order to ensure mutual polarity {en1; orientation holder, CTOiiKii lens and the 1 atomic glass plane at focusing iia sharpness, ohmic resistances are included in the opposite shoulders of the bridge, in the other two points they are equal to each other and are proportional to the focal length of the lens, and to one diagonal The bridge is connected to a direct current source, and to another - an indicator.

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