CN201222121Y - Double cross-hair division plate for detecting zoom lens boresight sway - Google Patents

Abstract

The utility model relates to a double-crosshair reticule for detecting shake of the visual axis of zoom lenses. Aiming to solve measurement problems of shaking of the visual axis of zoom lenses with large zoom ratio, a co-centric double-crosshair reticule is designed. Two co-centric crosshairs are scored at the center of the reticule, wherein the ratio of the width and the length of the large crosshair to that of the small crosshair is equal to the zoom ratio of the lens, the small crosshair is totally black while the large crosshair is lighter with 1/3-1/2 grayscale of that of the small crosshair, and the dark small crosshair is used to position the visual axis center of the long focus while the light large crosshair is used to position the visual axis center of the short focus, thereby obtaining high precision detecting result of shake of the visual axis of zoom lenses, and further solving the problem of visual axis shaking detection of zoom lenses with larger zoom ratio which can not be realized by the general method. Accuracy and feasibility of the detector and the detecting scheme are proved by reality, and further, the detecting instrument has simple structure, convenient usage, low cost and considerable value.

Description

The diesis wire division plate that a kind of zoom lens's of detection optical axis rocks

Technical field:

A kind of testing tool that the utility model relates to that optics is debug, use in the optical detection field promptly detects the diesis wire division plate that zoom lens's optical axis rocks.

Background technology:

The optical axis of zoom lens before and after focal length variations rocks and can cause the change in location of image in the visual field, if optical axis target deflects away from the visual field, center, can influence high-acruracy survey or TV and follow the tracks of.So, the zoom lens the design, debug with testing process in, the optical axis rocks and be controlled in certain margin tolerance.

Conventional sense zoom lens's optical axis method of rocking needs following several steps.(see figure 1)

First step:

As shown in Figure 1, it is coaxial arrange to detect parallel light tube, detected zoom lens, reading microscope, settles the crosshair graticule on the parallel light tube focal plane detecting, and the picture of the first crosshair graticule of zoomlens projects on zoom lens's the image planes.

Second step:

Detected zoom lens is adjusted to long burnt, fine setting reading microscope position makes the middle imago that detects parallel light tube crosshair graticule overlap with the graticule center of reading microscope, the reading microscope position (x when noting camera lens and being in long-focus ₁, y ₁).

Third step:

Adjust lens focus to short burnt, repeat second step, the reading microscope position (x when noting camera lens and being in short focal length ₂, y ₂).

The 4th step:

Position (x ₁, y ₁) and position (x ₂, y ₂) distance be exactly long and short Jiao's of zoom lens optical axis rolling momentum, be converted into angle as follows:

For the change multiple proportions is not king-sized conventional zoom lens, long burnt and short Jiao can blur-free imaging for camera lens for the crosshair graticule, measure the center of crosshair picture easily, can encounter problems but detect when the optical axis that becomes the bigger zoom lens of multiple proportions rocks, as shown in Figure 2.

$\frac{H}{F}=\frac{h}{f}---2)$

H: the line thickness that detects the crosshair on the parallel light tube focal plane

H: the crosshair on the zoom lens focal plane is as line thickness

F: detect the parallel light tube focal length

F: zoom lens's focal length

Can release:

$\frac{h_1}{h_2}=\frac{f_1}{f_2}---3)$

h ₁: the graduation printed line was wide when length was burnt,

h ₂: the graduation printed line was wide when weak point was burnt,

f ₁: the camera lens long-focus,

f ₂: the short focal length of camera lens,

Be crosshair on the zoom lens focal plane as line thickness than the focal length variations ratio that equals the zoom lens.The focal length variations ratio of supposing the zoom lens is 15～30 times, and it is clear to detect parallel light tube crosshair graticule imaging when the elongated focal length of camera lens.Crosshair is moderate as line thickness, and crosshair graticule inconocenter is exactly zoom lens's the burnt central visual axis of length.

Behind the zoom, according to formula 3), the crosshair graticule looks like to have dwindled 15～30 times, crosshair has also dwindled 15～30 times as line thickness, because crosshair is too thin as line thickness, the crosshair picture is too little, the great variety of long and short burnt image width, though cause when long-focus, can clearly seeing the crosshair picture clearly, can't when the weak point focal length, observe the crosshair picture, also just can't measure short burnt central visual axis.

Detect more that zoom lens's optical axis of hypermutation multiple proportions rocks, because long and short focus difference is apart from bigger, the contradiction of seeing crosshair graticule picture simultaneously clearly is irreconcilable further.

Micro objective or the eyepiece of changing higher multiple can amplify crosshair graticule picture when short Jiao, but may cause the reading microscope change in location, cause the optical axis to change, bring new error source, the accuracy of detection that reduction zoom lens's the optical axis rocks is so the method should not adopt.

Summary of the invention:

Rock the problem that to see the crosshair picture in the testing process simultaneously clearly for the zoom lens's optical axis that solves hypermutation multiple proportions in the background technology, the utility model has designed a kind of concentric diesis wire division plate, by delineate two concentric cross silks in the heart in a graticule, the length of two kinds of crosshairs, width and gray scale have certain variation.

Therefore, the utility model will provide a kind of hypermutation multiple proportions zoom lens optical axis to rock the concentric diesis wire division plate of detection.

Concentric diesis wire division plate concrete structure of the present utility model is as follows:

See Fig. 3, at first, determine the graticule center, delineate two concentric cross silks, the decentraction error of diesis wire division plate is rocked the accuracy of detection decision according to zoom lens's optical axis with one heart, generally gets 0.0005mm-0.001mm.

The width of the width of grand cross silk and length and little crosshair and length ratio equal the change multiple proportions of camera lens; The complete blacking of little crosshair, grand cross silk more light, gray scale is about the 1/3-1/2 of little crosshair.

Utilize concentric diesis wire division plate, detect zoom lens's optical axis routinely and rock 4 steps detections of method:

At first with dark little crosshair location long-focus central visual axis, this moment, light grand cross silk did not influence the dark little crosshair of microscopic examination.

When switching to camera lens weak point focal length, dark little crosshair is because size is less can't to be arrived with microscopic examination, and light grand cross silk is located short focal length central visual axis because image height dwindles and becomes clear all the more with it, finishes the optical axis that detects the zoom lens and rocks.

Advantage of the present utility model: the utility model proposes the optical axis that becomes the bigger zoom lens of multiple proportions and rock testing tool and using method.By special concentric diesis wire division plate, use the identical large and small crosshair in center to determine that zoom lens's the optical axis changes at long and short focal length respectively.The optical axis that has solved the bigger zoom lens of the change multiple proportions that can't realize according to a conventional method rocks detection.Embodiment of the present utility model has proved the correctness and the feasibility of this testing tool and detection scheme by the practical application in certain zoom lens's measurement.And instrument is simple, and is easy to use, with low cost, is worth considerable.

Description of drawings:

Fig. 1 zoom lens's the optical axis rocks the layout synoptic diagram: parallel light tube 1 among the figure, zoom lens 2 to be checked, and reading microscope 3, human eye 4,

Fig. 2 diesis silk thread imaging synoptic diagram: h ₁: the graduation printed line was wide when length was burnt, h ₂: the graduation printed line was wide when weak point was burnt, f ₁: camera lens long-focus, f ₂: the short focal length of camera lens, crosshair live width H, cross silk thread image width h.

Fig. 3 concentric diesis wire division plate synoptic diagram of the present utility model

Embodiment:

Embodiment of the present utility model such as Fig. 1, Fig. 2, shown in Figure 3,1,25 times of zoom lens to be checked 2 who becomes multiple proportions of 550mm parallel light tube, reading microscope 3, human eye 4, crosshair live width H, cross silk thread image width h.

Embodiment of the present utility model presses Fig. 1 and arranges, 1,25 times of zoom lens to be checked 2 who becomes multiple proportions of 550mm parallel light tube, and reading microscope 3 and human eye 4 are arranged to straight line.

Special concentric diesis wire division plate is placed on the focal plane of 550mm parallel light tube 1, the zoom lens is adjusted to long burnt position, human eye 4 is observed by reading microscope 3, and the visual center of reticule of reading microscope is overlapped with the little crosshair of special diesis wire division plate.Record reading microscope position (x at this moment ₁, y ₁).Adjust zoom lens 2 again to short burnt position, if reading microscope 3 visual center of reticules do not overlap with the grand cross silk of special diesis wire division plate, fine setting reading microscope position is to (x ₂, y ₂).

The optical axis that calculates the zoom lens with following formula rocks:

Claims (2)

1 one kinds are detected the diesis wire division plate that zoom lens's optical axis rocks, it is characterized in that:

At the graticule center, delineate two concentric cross silks, make concentric diesis wire division plate;

The width of the width of grand cross silk and length and little crosshair and length ratio equal the change multiple proportions of camera lens;

The complete blacking of little crosshair, grand cross silk more light, gray scale is the 1/3-1/2 of little crosshair;

2. the graticule that rocks according to the described a kind of zoom lens's of the detection optical axis of claim 1 is characterized in that the decentraction error of concentric diesis wire division plate is rocked the accuracy of detection decision according to zoom lens's optical axis, generally gets 0.0005mm-0.001mm.

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