CN101246263A - Double-cross wire division plate for detecting visual axis shake of zoom lens and use method thereof - Google Patents

Abstract

In order to solve the problem for testing big zoom ratio lens visual axis sway, a concentric double cross line reticule is designed, two concentric double cross lines are scored in the center of the reticule, the ratio between the width and the length of the big double cross line and the width and the length of the small cross line is equal to the zoom ratio; the small cross line is completely painted black, the color of the big cross line is lighter, the gray scale thereof is 1/2-1/3 of the small cross line; the long focus visual axis center is positioned with dark small cross line, the short focus visual axis center is positioned with light big cross line, the high accuracy test result of the zoom lens visual axis sway is obtained. The invention solves the problem that the visual axis sway test of zoom lens with big zoom ratio can not be realized by ordinary method. According to the particle application, the correctness and feasibility of the test tool and test program are proved. And the invention has the advantages of simple tool, convenient usage, low cost and considerable value.

Description

Detect diesis wire division plate and using method that zoom lens's optical axis rocks

Technical field:

A kind of testing tool that the present invention relates to that optics is debug, uses in the optical detection field promptly detects graticule and using method thereof 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:

(radian) 1)

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 special a kind of concentric diesis wire division plate of the present invention, 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.

With one group of crosshair location long-focus central visual axis, with another short focal length central visual axis in group crosshair location, whole process need not to change microlens, helps obtaining zoom lens's optical axis and rocks the high Precision Detection result.Therefore, the present invention will provide a kind of hypermutation multiple proportions zoom lens optical axis to rock the crosshair graticule method for making and the using method of detection.

Crosshair graticule concrete structure of the present invention is as follows:

See Fig. 3, at first, determine the graticule center, delineate two concentric cross silks, the decentraction error is rocked the accuracy of detection decision according to zoom lens's optical axis, generally gets 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 1/3 of a little crosshair.

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 invention: the present invention 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.Embodiments of the invention have 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: 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

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

Embodiment:

Embodiments of the invention 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 5, cross silk thread image width 6.

Embodiments of the invention are pressed Fig. 1 and are arranged, 1,25 times of zoom lens to be checked 2, reading microscope 3 and human eyes 4 that become multiple proportions of 550mm parallel light tube are arranged to straight line.

First step:

Detecting the concentric diesis wire division plate of arrangement on parallel light tube 1 focal plane, zoom lens 2 projects the picture of concentric diesis wire division plates on zoom lens 2 the image planes;

Second step:

Detected zoom lens 2 is adjusted to long burnt, fine setting reading microscope 3 positions, 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, the reading microscope 3 position (x when noting camera lens and being in long-focus ₁, y ₁);

Third step:

Adjust zoom lens 2 focal lengths to short burnt, repeat second step, when switching to camera lens weak point focal length, dark little crosshair can't be observed with microscope 3 because size is less, and light grand cross silk becomes clear all the more owing to image height dwindles, locate short focal length central visual axis with it, the reading microscope 3 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:

(radian) 1).

Claims (3)

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 diesis wire division plate that rocks according to the described a kind of zoom lens's of the detection optical axis of claim 1, the decentraction error that it is characterized in that 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.

3, the using method of the diesis wire division plate that rocks of a kind of zoom lens's of detection optical axis is characterized in that the using method of this concentric diesis wire division plate:

First step:

It is coaxial arrange to detect parallel light tube, detected zoom lens, reading microscope, settles concentric diesis wire division plate on the parallel light tube focal plane detecting, and the picture of the first concentric diesis wire division plate of zoomlens projects on zoom lens's the image planes;

Second step:

Detected zoom lens is adjusted to long burnt, the long-focus central visual axis is at first located with dark little crosshair in fine setting reading microscope position, 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, dark little crosshair can't arrive with microscopic examination because size is less, 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, 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:

(radian) 1).

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