CN2840920Y

CN2840920Y - Optometry instrument adopting split-screen optical wedge for focusing

Info

Publication number: CN2840920Y
Application number: CN 200520040664
Authority: CN
Inventors: 唐大昌
Original assignee: SHANGHAI DONGMENZI INSTRUMENT & METER Co Ltd
Current assignee: SHANGHAI DONGMENZI INSTRUMENT & METER Co Ltd
Priority date: 2005-04-05
Filing date: 2005-04-05
Publication date: 2006-11-29
Anticipated expiration: 2015-04-05

Abstract

The utility model belongs to the technical field of optical instruments and is an improvement for original optometry instruments, particularly for an optometry instrument by adopting split-screen optical wedges for focusing. Specifically, a split-screen double optical wedge rangefinder is arranged between an image rotation objective lens and an objective lens of the optometry instrument; the rangefinder is composed of two semicircle-shaped optical wedges which are symmetrically arranged. An intersection point of the optometry instrument and an image are in a same plane, so imaging lines on a view finding screen form a continuous and clear straight line during focus adjustment; in other words, the focusing is successful. The imaging lines on the view finding screen form a crossing shape, which means that the focusing is failed so that the focusing is adjusted again. In the terms of human being's visual sense, the judgment whether the two lines are coincident or not is more convenient than the judgment whether the image is clear or not. Therefore, the split-screen double optical wedges are used for the focusing, which improves the precision and the speed of the focusing.

Description

Adopt the eye refractometer of split image wedge focusing

Technical field

This utility model belongs to the optical instrument technical field, is specifically related to a kind of eye refractometer that adopts the split image wedge focusing.

Background technology

Eye refractometer is a kind of people's eyes to be carried out the precision instrument of objective or subjective measurement, and it can measure diopter, post mirror degree and the axle position of eyes, for the eyes diagnosis and treatment with join mirror supplemental characteristic is provided.Eye refractometer adopts Image Information Processing, multinomial new and high technologies such as optical system, intelligent circuit, and light harvesting electromechanics is one, by near infrared light human eye measuring system, gathers and analyze the reflected image on human eye optical fundus, obtains the optometry data through software processes.

Eye refractometer needs tested eyes are carried out detection and location when optometry, promptly determines the eyes measuring basis.

Adopt general image planes localization method in the eye refractometer in the past, promptly tested eyes looked like to be presented on the screen, by optometrist operation eye refractometer, make on the screen eyes look like to transfer to clear after, carry out optometry and measure.Because the clear and definite absolute bound of neither one between picture clear and fuzzy is so be difficult in this way accomplish fast and accurately locate.The location is inaccurate, can influence the optometry certainty of measurement.

Summary of the invention

The purpose of this utility model be to design a kind of can quick, pinpoint eye refractometer to image planes.

The eye refractometer that the utility model proposes, be improvement, promptly in the light path of former eye refractometer, between image rotation object lens and CCD object lens, be provided with one and split the two wedge range finders of picture former eye refractometer, this range finder is made up of two semicircle wedge balanced configurations, the intersection point of wedge and image planes coplane.Its structure is seen shown in Fig. 1 (a).

In this utility model, also can not establish the image rotation object lens, split the two wedge range finders of picture and be set directly between object lens and the CCD object lens, its structure is seen shown in Fig. 1 (b).

In this utility model, the wedge angle of splitting the two wedge range finders of picture is generally 7 °-12 °.

In this utility model, the structure and layout of all the other opticses are similar or identical with original eye refractometer.

This utility model has been broken through original image planes localization method, has adopted to split the two wedge range finders of picture in eye refractometer, and this range finder adopts two semicircular wedge balanced configurations, makes its intersection point and image planes coplane.If a lines picture is arranged, picture point is adjusted on the intersection point of two wedges just, similarly is a straight line clearly on image planes so, and, still on a linear position, the whole screen of finding a view obtains a complete successive again straight line to the picture of incident ray after two wedge refractions.If picture point drop on the wedge intersection point above or below the time, similarly be a fuzzy straight line on the screen then, and the picture of incident ray after two wedges refractions depart from towards both sides respectively, i.e. the broken string of fork about occurring on the wedge.Illustrate that focusing is inaccurate.Concerning people's vision, judge that whether the two wires overlaps than judgement similarly is to deny clearly to make things convenient for manyly, therefore focus and can improve the precision and the speed of focusing greatly with splitting the two wedges of picture.

With the split image wedge focusing, its precision of focusing---separation degree is relevant with the wedge angle.If require focusing precision height, need to increase the wedge angle.When identical error, the wedge angle is big more, and its two-wire separation degree is also big more, just can distinguish by human eye more.But the wedge angle is strengthened, except that the chromatic dispersion that strengthens lines is fuzzy, also can produce outgoing pupil fractional dose strengthens, causing emergent pupil to overlap the district reduces, make the CCD accepter can not accept two-way light beam by two wedges simultaneously, thereby produce the dark space, influence is used, Gu Guangxiejiao should get suitable angle, and this utility model can be taken as 7 °-12 °.

Because it is people's eyes are spheroids, generally proper on eye refractometer with the focusing of garden loop wire bar.The focusing loop wire is the target ring picture of measured's eyes corneal reflex, this picture is focused and has been improved focusing precision and speed greatly with splitting picture pair wedges, promptly improve eyes measuring basis positioning accuracy, thereby also improved the correctness of human eye being carried out objective measurement or subjective measurement.

Description of drawings

Fig. 1 is a structure principle chart of the present utility model.Wherein, Fig. 1 (a) is the image rotation object lens.Fig. 1 (b) is no image rotation object lens.

Fig. 2 is a structural diagrams of the present utility model.

Fig. 3 is for splitting the two wedge range finder wedge mirror diagrams of picture.

Fig. 4 is the focusing effect diagram of this device.Wherein, Fig. 4 (a) staggers for the ring end, and focusing is not enough.Fig. 4 (b) staggers for the ring end, and it is excessive to focus.Fig. 4 (c) aims at for focal length.

Number in the figure: 1 is people's eyeball, and 2 is the infrared target of garden annular, and 3 is lighting source, and 4 is object lens, 5 is the image rotation object lens, and 6 for splitting the two wedge range finders of picture, and 7 is the CCD object lens, and 8 is the CCD accepter, 9 are signal output, and 10 is the infrared mark ring of eyes corneal reflex, and 11 are the screen of finding a view, and α is the wedge angle.

The specific embodiment

Further specify this utility model below by embodiment and accompanying drawing.

As shown in Figure 1, eye refractometer by the infrared target 2 of annular, lighting source 3, object lens 4, image rotation object lens 5, split the two wedge range finders 6 of picture, CCD object lens 7, CCD accepter 8 successively light path connect to form.Wherein, the diameter phi 35mm of the infrared target 2 of annular, ring width 1.5mm, apart from being subjected to inspection eye 37mm, lighting source 3 adopts far-infrared light-emitting diode display.

Focal distance f=the 37mm of object lens 4, with the distance of target be 25mm.

Focal distance f=the 13mm of image-forming objective lens 5, with the distance of object lens 4 be 45mm.

Splitting the two wedge range finders 6 of picture is 8.5mm apart from the distance of imaging len 5.

Focal distance f=the 38mm of CCD object lens 7 is 60mm with splitting the distance that looks like two wedge range finders 6.

CD accepter 8 is 100mm apart from the distance of CCD object lens 7.Assemble by Fig. 1, regulate, promptly obtain this utility model eye refractometer.

During use, the round ring target reflects on the eyes cornea after shining, and is imaged on the split image wedge through object lens 4 and image rotation object lens 5, and is imaged on the CCD target surface by CCD object lens 7, exports on the indicator screen.Mobile eye refractometer makes on the screen garden annular target lines overlap and has just realized the accurate location of eye refractometer to tested eyes measuring distance.

Original eye refractometer is being measured 1500 standard analogs of spending at the moment, and the repeated measure trueness error is 50 degree-75 degree.After the two wedge range finders of picture were split in employing, at the standard analog of measuring 1500 degree at the moment, the repeated measure trueness error was the 12-25 degree.Certainty of measurement greatly improves.In addition, focusing speed is also accelerated greatly.

Claims

1, a kind of eye refractometer that adopts the split image wedge focusing, it is characterized in that between image rotation object lens (5) and CCD object lens (7), being provided with one and split the two wedge range finders (6) of picture, this range finder (6) is made up of two semicircle wedge balanced configurations, the intersection point of wedge and image planes coplane.

2, eye refractometer according to claim 1 is characterized in that splitting the two wedge range finders (6) of picture and is set directly between object lens (4) and the CCD object lens (7), does not change object lens (5) and be not provided with.

3, eye refractometer according to claim 1 and 2 is characterized in that the described light locking angle that splits the two wedge range finders of picture is 7 °-12 °.