CN1291281A - Objective measurement and correction of optical systems using wavefront analysis - Google Patents

Abstract

A system and method for objective measurement and correction of focusing optical systems comprising optics disposed in the path of the beam which directs the beam through the focusing optical system, e.g., and eye and focuses the beam at its rear portion. The beam is diffusely reflected back and a wavefront analyzer is disposed in the path of the wavefront projected from the optics and calculates the distortions as an estimate of aberrations of the focusing optical system.

Description

Use the objective measurement and the correction of the optical system of wavefront analysis

The present invention relates generally to that optical aberration is measured and correction, more particularly, relate to the objective measurement and the correction of the optical system of the real image focus that has such as the humans and animals eyes.

Optical system with real image focus can receive collimated light, and on focusing on it a bit.Such optical system can find that for example the humans and animals eyes perhaps can be artificial, for example laboratory system, navigational system etc. at occurring in nature.Under any situation, the aberration in optical system can influence the performance of system.By example, will use human eye to explain this problem.

With reference to Figure 1A, represent a perfection or desirable eyes 100, it reflects bump light beam (for the sake of clarity not expression) diffusely from the eye optical system of its retina 102 rear portions (being central fovea 103) through comprising lens 104 and cornea 106.For under relaxation state, promptly be unsuitable for providing the near field to focus on, a kind of so desirable eyes, reflected light (by arrow 108 expressions) leaves eyes 100 according to the plane wave order, its one of represent with straight line 110.Yet eyes have the distortion that causes the ripple that leaves eyes or the aberration of distortion usually.This represents that by the example among Figure 1B the eyes 120 that wherein distort reflect bump light beam (equally for the sake of clarity not expression) from the rear portion of its retina 122 of central fovea 123 diffusely through lens 124 and cornea 126.For the distortion eyes 120, reflected light 128 leaves eyes 120 by the order of distorted wavefront, its one of represent with wave 130.

At present, multiple technology of attempting to provide for patient the improvement eyesight is arranged.The example of this technology comprises that using refraction laser surgery or interior cornea to implant refigure cornea 126 and the implantation of use intraocular lens and correct grinding glasses adds synthetic lens on the optical system to.Under each situation, the treatment for correcting amount is generally by being placed on spectacle plane place (at cornea 126 precontract 1.0-1.5 centimetres) to the sphere of known refracting power and/or cylindrical lens and asking which kind of lens of patient or combination of lenses provide the most clearly vision to determine.This obviously is the very out of true measurement of wavefront 130 real distortions, apply the compensation of single goalpost face, 2 because 1) stride across whole wavefront) test eyesight down in the Discrete intervals (that is diopter unit) of refraction correction, and 3) need to determine, so that determine optical correction by patient's subjectivity.Thereby it is accurate that the conventional method that is used for determining the eyes refraction error not can be used to proofread and correct the technology of eyepiece aberration basically now.

In " the objective automatic refractometer of spatial discrimination ", U.S. Patent No. 5,258,791 is published in 2,1993 on November open a kind of method of measuring eyepiece refraction error by Penney etc.Penney etc. have lectured the use of automatic refractometer, to measure the refraction of eyes at a plurality of discrete positions place that strides across anterior corneal surface.Automatic refractometer is designed to the arrow beam of light of optical radiation be sent to ocular surface and use the retina imaging system to determine that this impinging light beam is to where amphiblestroid.But direction of beam propagation all is independent regulation with respect to the angle of systematic optical axis and impinging light beam to the apparent position of eyes anterior corneal surface.Be incident on the less uncertainty of the light beam spot position on the cornea or error owing to crooked anterior corneal surface exists.To striding across each point of anterior corneal surface incident,, can determine that the eyes corresponding with this surface point reflect by regulating the impinging light beam cornea up to being refracted to impinging light beam on the iris to the angle of central fovea.The adjusting of propagating beam angle can manually realize by patient, if perhaps include the backfeed loop that relates to the cornea imageable element then automatically realized by automatic refractometer.

Penney etc. have further lectured and have determined the use that automatic refractometer is measured when providing emmetropia that is shaped again of suitable anterior corneal surface.This realizes (using the industrial available apparatus of separating) by the accurate measurement that at first obtains the anterior corneal surface profile.Then, use initial cornea profile in each surperficial datum, the measurement refraction at each surface point place, and Snell laws of refraction carry out mathematical analysis, change in the requirement of the surface profile of each datum determining.Combined profile variations then in each datum, to realize striding across single that whole anterior corneal surfaces will apply shaped profile again.

Major limitation by the method for descriptions such as Penney is the independent measurement of cornea profile need to require the snell law analysis of change in refraction.This requirement has significantly increased time and the cost of finishing diagnostic evaluation.And the precision of change in refraction analysis will depend on the precision of profile measurement and the precision that automatic refractometer is measured.In addition, profile " figure " will reduce the precision of the profile that needs correction with respect to any error of the spatial orientation of refraction diagram.

To being limited in the testing site of sequential search on anterior corneal surface by second of the method for descriptions such as Penney.During checking have a mind to or unintentionally eye motion can be incorporated into significant error during refraction measures.Penney etc. attempt by deliberately being included in outside the pupil, promptly in the cornea zone of overlapping iris, measurement point, the detection of this eye motion is provided, wherein the specific interval place in checks sequence obviously is zero from amphiblestroid returning.Yet this method may still allow significantly not detect the eye motion error between such iris reference point.

Check when now, bearing calibration is based on the complete distortion of wavefront 130.The human eye wave aberration is the measurement of eyepiece aberration, after deliberation for many years.A kind of method and system of prior art by Liang etc. at " utilizing the objective measurement of the human eye wave aberration of Hartmann-Shack Wavefront sensor " Journal of the Optical Society of America, volume 11, No.7, in July, 1994, open among the p.p.1949-1957.Liang etc. have lectured use Hartmann-Shack Wavefront sensor, by measuring by the retinal reflex of the laser focusing point on the amphiblestroid central fovea wavefront from the eyes appearance, come the measuring eyepiece aberration.Use has the polynomial wavefront of Zernike and estimates to reconstruct actual wavefront.

Comprise two identical layers of circle lens by disclosed Hartmann-Shack Wavefront sensors such as Liang, layer is so arranged, thereby the lens in every layer are perpendicular to one another.By this way, the two-layer spherical lenslet of two-dimensional array that plays incident light wave is divided into sub-aperture.The light belt that passes each sub-aperture in the focal plane that focuses on the resident lens arra of one of them charge-coupled device (CCD) picture module.

The system of Liang etc. calibrates by desirable optical plane ripple is impinged upon on the optical lens array, thereby benchmark or the imaging of calibration focused spot pattern are on CCD.Because desirable wavefront is the plane, so each spot relevant with desirable wavefront is positioned on the optical axis of corresponding lenslet.When distorted wavefront passed through lenslet array, the image point on CCD moved with respect to the reference pattern that is produced by desirable wavefront.Each slope local that moves with distorted wavefront is that partial derivative is proportional, and this distorted wavefront estimates by means of having the polynomial typical wavefront of Zernike, can be used for reconstituting distorted wavefront.

Yet, only effective for eyes with better eyesight by disclosed systems such as Liang.The eyes that present degree of depth myopia (myopia) cause that focused spot overlaps on CCD, and it is impossible making slope local determine for the eyes with this state thus.Similarly, present the eye reflections focused spot of degree of depth long sight (long sight), thereby they can not strike on the CCD, it is impossible making slope local determine for the eyes with this state equally thus.

The another kind of the system of Liang etc. is limited in the configuration of Hartmann-Shack sensor: lens must be that so that limit uniform lenslet array, thereby whole array is shared a common focal plane, and itself can not produce the distortion of wavefront uniformly.Yet the manufacturing cost relevant with such restriction is sizable.

Thereby owing to above-mentioned institute is restricted, Liang etc. only can realize wavefront measurement for the patient of less classification.These patients can have the vision of moderate distortion at the most.

One object of the present invention is, provide a kind of by wavefront analysis be used for the objective measurement optical system aberration and be used for using this measurement to produce the method and system of optical correction.

Another object of the present invention is, the objective measurement of the eyepiece aberration with dynamic range is provided, and can handle a large amount of this aberrations, so that be used in the practical use.

Another purpose of the present invention is, the method and system that provides a kind of wavefront analysis device that uses simple and cheap structure to be used for objective measurement eyepiece aberration.

In instructions and accompanying drawing, will become clearer below other purposes of the present invention and the advantage.

According to the present invention, energy source produces radiation laser beam.Be arranged in the optical system in the beam path, directing light beams is by Focused Optical system, for example eyes of its rear diffusion reflector effect.Light beam is as the wavefront of the radiation by Focused Optical system, and the reflected back diffusely from the rear portion impinges upon on the optical system.When wavefront when Focused Optical system occurs, optical system wavefront to project on the wavefront analysis device with the direct corresponding of wavefront.The wavefront analysis device is arranged in from the path of the wavefront of optical system projection, and calculates the distortion of wavefront, as the estimation of the eyepiece aberration of Focused Optical system.The wavefront analysis device comprises a Wavefront sensor, and this sensor is connected to analyte sensors data with on the processor that re-constructs the wavefront that comprises its distortion.

In one embodiment, radiation is optical radiation, and uses a planar array of a plate and light activated element to realize Wavefront sensor.This plate generally is opaque, but has the transmittance array of apertures that a selectivity allows bump light therefrom pass through.This plate is arranged in the path of wavefront, thereby wavefront is partly by the transmittance aperture.The planar array of element is parallel to this plate arranges, and separates the distance of selection with plate.Each part of passing the wavefront in one of transmittance aperture shows the geometric configuration that covers unique a plurality of elements.In another embodiment, Wavefront sensor comprises the planar array of the two-dimensional array and an element of a spherical lenslet.The lenslet array definition is from one focal length focal plane far away.Lenslet array is arranged in the wavefront path that wherein part of wavefront is therefrom passed.The planar array of element is parallel to lenslet array arranges, and separates a chosen distance that is independent of focal length with lenslet array.Be similar to the first embodiment Wavefront sensor, each part of wavefront shows the geometric configuration that covers unique a plurality of elements.Ignore and use which kind of Wavefront sensor, the distance between element planar array and opaque plate or lenslet array can change, and gains with the slope measurement of regulating Wavefront sensor, and improves the dynamic range of system thus.

The another kind of measure that dynamic range improves is provided by Focused Optical system.Focused Optical system comprises with the fixed position and remains on first and second lens in the path of light beam and wavefront.In the path of light beam and wavefront, between lens, arrange the arrangement of optical element.Optical element is adjustable, to change the optical path length between lens.

If wish optical correction, then distortion is converted to optical correction, if this optical correction is placed in the path of wavefront, cause then that wavefront is approximate to occur with plane wave.Optical correction can have the form of lens or from the amount of eyes ablation corneal material.

Figure 1A is the synoptic diagram that light is reflected into the desirable eyes of plane wave front from its retina;

Figure 1B is the synoptic diagram that the aberration eyes are arranged that light is reflected into distorted wavefront from its retina;

Fig. 1 C is the synoptic diagram with respect to the distorted wavefront of reference plane, is illustrated in wavefront error or the optical path difference of the direction of propagation as the function of lateral separation;

Fig. 1 D be with respect to the synoptic diagram of the distorted wavefront of the tangent reference plane of corneal plane;

Fig. 2 is the rough schematic view that is used for determining the system of eyepiece aberration according to essential characteristic of the present invention;

Fig. 3 is the synoptic diagram of an embodiment of the Hartmann-Shack wavefront analysis device that uses in the present invention;

Fig. 4 is the stereographic map that comprises from the part of the pinhole imaging plate of the Wavefront sensor of Fig. 3 embodiment and light activated element planar array, wherein represents the reflection of the wavefront sheet relevant with the aberration eyes are arranged, and compares with wavefront sheet or the plane wave front relevant with calibration;

Fig. 5 is the planimetric map of the indicating area on the light activated element planar array relevant with corresponding aperture;

Fig. 6 is the synoptic diagram of another embodiment of the wavefront analysis device that uses in the present invention;

Fig. 7 is the synoptic diagram that is suitable for one embodiment of the present of invention of ophthalmology use; And

Fig. 8 is the side view of cornea, and expression is as the thickness of the corneal material that will be ablated by the optical correction of the present invention's generation.

By the property said example, the present invention is described with respect to diagnosis and correction human eye.Yet, should be appreciated that technology of the present invention is applicable to any optical system with real image focus, this focus can (maybe can be suitable for) from optical system rear portion reflected back radiation diffusely focused spot by optical system as radiated wave before.Thereby the present invention can be for being human or animal's eyes of patient that live or dead or satisfying usefulness about any artificial optical system of real image focus.

With reference to the eyes example with by means of the synoptic diagram shown in Fig. 1 C, the method for using wavefront analysis to determine suitable optical correction will be introduced.For convenience's sake, define a coordinate system, upwards, positive y is outside from drawing, and positive z is to the right along the direction of propagation in drawing for wherein positive x.Distorted wavefront 130 can with mathematical method be described as W (x, y).

Measurement in a kind of method of wavefront 130 distortions is, determine from the reference plane 131 (being similar to desirable wavefront 110) at eyes known distance z0 place when distance z 0 is traversed in the forward position of wavefront 130 at each (x, y) the space interval △ z between the some place of distorted wavefront 130.This shows in Fig. 1 C, and is described as with mathematical method

△z(x，y)=z ₀-w(x，y) (1)

These △ z measure the inappropriate optical path difference that definition is caused by the aberration of test eye.Suitable correction comprises removes these optical path differences.Ideally, carry out this correction at reference plane 131 places.

According to proofreading and correct therapy (that is, cornea tissue is ablated, synthetic lens interpolation etc.),, then can directly calculate (x, y) the coordinate place quantity of material removing or add if the refractive index of the material of discussing is known at each.For various procedures, implant or ceratotomy radially as intraocular lens, during process, can carry out this analysis that has repeatedly, so that the feedback information about the suitable terminal point of process to be provided.

According to illustrative example, (x y) is the result of eyes aberration to the poor △ z between distortion and desirable wavefront.The ideal of these aberrations is proofreaied and correct and is comprised and introduce negative △ z (x is y) in the optical path difference at reference plane 131 places.Remove tissue if methods of treatment comprises from anterior corneal surface by laser ablation, selecting for the logic of reference plane 131 location so is surperficial tangent (that is z, with cornea 126 ₀=0).This schematically is illustrated among Fig. 1 D, and wherein the bending of cornea 126 is amplified for the purpose of clear widely in order to show.Carry and the eye tracking system by a laser beam then, as at U.S. Patent Application Serial Number No.08/232, disclosed the sort of in 615, along cornea at each (x, y) the coordinate place can carry out ablation independently, this patented claim was owned by identical grantor of the present invention on April 25th, 1994, and was included in here by reference.

(x, y) the suitable cornea ablation depth at lateral coordinates place is provided by following formula in little error range any

△z(x，y)／(n _c-1) (2)

N wherein _cIt is the reflectivity or 1.3775 of cornea tissue.The method of describing in detail below is by at first measuring the slope local in wavefront 130, promptly in reference plane 131 the horizontal δ W at a plurality of somes place of x and y direction (x, y)/δ x and δ W (x, y)/δ y; And produce then W with slope consistent with experiment determined value most probable (x, mathematical description y), calculating △ z (x, y).A kind of such slope δ W (x ₀, y ₀)/δ x is illustrated among Fig. 1 D.In doing so, wavefront 130 comes from the fact on the just bending after reference plane 131 (cornea) surface owing to measure distorted wavefront 130 at reference plane 131 places, introduces less error.This error is similar to the error that the prior art method with Penney discussed above etc. runs into.Error E _x(x, y) be measurement plane (that is, reference plane 131) be in each (x, y) position in x side upward to the lateral shift of crooked anterior corneal surface.Like error is understood for any correction that relates to the curved optical surface.Error is generally with (x, y) displacement and the local wavefront error increase of leaving the point of contact.

For at arbitrary coordinate, (x for example ₀, y ₀), (x y), by this position being throwed back the initial point on the cornea 126, can obtain error E in each measuring position of locating to measure _x(x, numerical value y).This can use Fig. 1 D to explain with mathematical method.For simplicity, explain that assumption error is only in drawing, promptly by y=y ₀The plane of definition comprises that the y scale error is very simple on mathematics but analysis expanded to.At z from anterior corneal surface to reference plane ₀In the reference plane at (x ₀, y ₀) quantification of the line L that propagates of the tracking wavefront element locating to measure is $L\left(x\right)=z_0-\frac{(x-x_0)}{\mathrm{\δW}(x_0,y_0)/\mathrm{\δx}}--\left(3\right)$

If by expression formula S (x ₀, y ₀) anterior corneal surface in the plane of the figure that describes, so by obtaining at L (x) and S (x ₀, y ₀) between joining, can find the initial point that is used for the wavefront element.On mathematics, this requirement is obtained and is satisfied L (x ＇)=S (x ₀, y ₀) value x ＇.Then as E _x(x ₀, y ₀)=x ＇-x ₀Provide error E _x(x ₀, y ₀).Analysis is expanded to consideration will produce for E in the error of y direction _ySimilar expression formula, E wherein _y(x ₀, y ₀)=y ＇-y ₀If influential, then pass through handle at each (x, y) the aberration correction amount of the being displaced sideways E of coordinate place calculating _x(x, y) and E _y(x y) can compensate these lateral errors.

Under the situation of human corneal, lateral error in most of the cases is insignificant.The tangent initial point place of cornea tissue and reference plane 131 therein, error is zero.For human corneal, it is spherical that tissue is approximately, and has the bending radius of about 7.5-8.0mm.The correction treatment radius generally is not more than 3mm, and the local wavefront bending radius almost always surpasses 50mm (20 dioptric refraction error).The lateral error little 40mm of local wavefront bending radius under 3mm treatment radius for 50mm.

For certain ophthalmic procedures, during trimming process, also can use wavefront analysis repeatedly to provide the feedback information of usefulness.An example of this use is in cataract operation, wherein can carry out wavefront analysis to eyes after the placement of lens implantation (IOL) within the eye.This analysis helps to distinguish the IOL that whether inserts suitable refracting power, perhaps whether should use different refracting power IOL.Another example that repeats wavefront analysis is during ceratoplasty, wherein deliberately twists eye's cornea by the mechanical tension that changes around its edge.Here, repeat wavefront analysis and can be used for selectedly, the instrument of the best surface bending that obtains being used for best eyesight is provided thus in the tension variation degree of locating to produce around every of cornea.

For with carry out wavefront analysis such as the compatible mode of above-mentioned trimming process those, must measure the apart amount of the component of wavefront 130 with respect to the respective component part of plane or desirable wavefront.System and method of the present invention just, even the aberration eyes are significantly arranged for those that comprise that those present major defect such as serious myopia and long sight, also allow objective with measure this separation exactly.

For estimation of the present invention or measure portion, patient's pupil should be diffused into approximate 6 millimeters or bigger ideally, i.e. the typical sizes of human pupil under low-light (level).By this way, when using the cornea maximum region, estimate eyes, thereby consider the maximum available angle diaphragm area of patient's eyes by any correction that this measurement produces.(use a small amount of of cornea in sight, wherein pupil is significantly less, for example on 3 millimeters magnitude.) by in the low-light (level) environment such as the darkroom, implementing measure portion of the present invention, can produce diffusion naturally.By making with medicament also can produce diffusion.

Referring now to Fig. 2, the rough schematic view of the system of the present invention of its primary element is described in expression, and generally with label 10 indications.System 10 comprises the laser instrument 12 that is used for producing optical radiation, is used for producing the minor diameter laser beam.Laser instrument 12 generally is the laser instrument of a generation to the wavelength of eye-safe and the collimation laser light of power (by dotted line 14 expressions).For ophthalmic applications, suitable wavelength comprises from the whole visible spectrum of about 400-710 nanometer with from the infrared spectrum of about 710-1000 nanometer.Although the operation in visible spectrum generally is best (because these are wherein the condition of eyes work), can be provided in advantage in certain purposes near infrared spectrum.For example, if patient does not know to measure, then patient's eyes may more loosen.With the Wavelength-independent of optical radiation, should be in ophthalmic applications the grade of Power Limitation to eye-safe.For laser emission, suitable eye-safe exposure grade can find in the United States Federal's performance standard that is used for laser product.If analyzing is to carry out on the optical system rather than on eyes, check that then wavelength coverage should be included in the indicative energy range of system in logic.

In order to select the minor diameter collimation heart portion of laser light 14, can use an iris ring 16 to block except that all laser light 14 of using by the present invention the laser beam 18 of wishing size.According to the present invention, laser beam 18 can have in the scope of about 0.5-4.5 millimeter, the 1-3 millimeter is typical diameter.The eyes of serious aberration require than small diameter optical beam, and only have the eyes of slight aberration to estimate with diameter beam of heap of stone.Output according to laser instrument 12 is dispersed, and can locate a lens (not shown) to optimize collimation in beam path.

Laser beam 18 is to pass the light beam of Polarization-Sensitive beam splitter 20 directional focusing optical systems 22 on the way.Optical system 22 operations are to focus on laser beam 18 rear portion of eye retina 122 through the optical system (for example, cornea 126, pupil 125 and lens 124) of eyes 120.(should be appreciated that, may be non-existent for the patient's lens 124 that carry out the cataract process, yet this does not influence the present invention).In the example that shows, optical system 22 laser beam 18 or be a small light spot near the central fovea 123 places imaging of eyes, the sensitiveest in vision of these place's eyes.Attention can be reflected another part that small light spot leaves retina 122, so that determine the aberration relevant on the other hand with people's vision.For example, if flare leaves the zone of retina 122 around central fovea 123, then can estimate the special aberration relevant with people's peripheral vision.In all cases, decide the size of hot spot, on retina 122, to form nearly diffraction-limited image.Thereby the hot spot that is produced by laser beam 18 at central fovea 123 places is no more than about 100 microns on diameter, and general on 10 microns magnitude.

The scattered reflection of the laser beam of returning from retina 122 18 is illustrated in Fig. 2 with solid line 24, the wavefront of the radiation that indication is returned through eyes 120.Wavefront 24 bumps and the optical system 22 of passing on the way arrive Polarization-Sensitive beam splitter 20.When wavefront 24 leaves retina 122, wavefront 24 since reflection and diffraction go partially with respect to laser beam 18.Thereby wavefront 24 turns at Polarization-Sensitive beam splitter 20 places, and points to a wavefront analysis device 26, as Hartmann-Shack (H-S) wavefront analysis device.In general, wavefront analysis device 26 is measured the slope of wavefront 24, promptly at a plurality of (x, y) partial derivatives of relative x in lateral coordinates place and y.This partial derivative information is used for re-constructing or be similar to original wavefront by means of the mathematic(al) representation such as Zernike polynomial expression weighting sequence.

The purpose that is used for the above regulation polarization state of incoming laser beam 18 and beam splitter 20 is, reduces to arrive the stray laser radiant quantity of the Sensor section of wavefront analysis device 26.In some cases, stray radiation when with from wishing that radiation that target (for example, retina 122) is returned may be enough little when comparing, thereby above polarization regulation is unnecessary.

The present invention can be suitable for the defects of vision of wide region, and reaches a new dynamic range grade according to the measuring eyepiece aberration like this.By means of now the optical system 22 of explanation and/or the Wavefront sensor of wavefront analysis device 26 being realized that partly dynamic range improves.

In the embodiment that shows, optical system 22 comprises one first lens 220, level crossing 221, a Porro mirror 222 and one second lens 224, and all these is along the access arrangements of laser beam 18 and wavefront 24.First lens 220 and second lens 224 are the identical lens that remain on the fixed position.Porro mirror 222 can linear movement as indicated by arrow 223, to change the optical path length between lens 220 and 224.Yet should be appreciated that, the invention is not restricted to the concrete layout of level crossing 221 and Porro mirror 222, and other optical arrangement can be used between lens 220 and 224, to change the optical path length between it.

By the eyes 120 among the wide beam source (not shown) replacement Fig. 2 that uses the collimated light of simulating perfect plane wave, can distinguish " zero position " of Porro mirror 222.Detect the light of collimation by with a light beam telescope laser beam being expanded to the diameter of the one-tenth image plane that covers wavefront analysis device 26 and regulating Porro mirror 222 up to wavefront analysis device 26, can realize such provenance.Attention can be calibrated with diopter by the variation of the optical path length that Porro mirror 222 produces, and proofreaies and correct so that the almost spherical diopter that below will further explain to be provided.

Comprise a wavefront analysis device that improves the most preferred embodiment of wavefront sensing apparatus by utilization, can further improve the dynamic range of system 10.To explain a kind of such wavefront sensing apparatus now by means of Fig. 3 and 4.In Fig. 3, the wavefront analysis device comprises: an opaque imaging plate 32 has and passes one of them hole array 34; The planar array 36 of a light sensor is as charge-coupled image sensor element 38; And a processor 40, be connected on the planar array 36 of element 38.The combination of plate 32 and planar array 36 comprises unique Wavefront sensor of this embodiment.Plate 32 remains parallel to planar array 36, and is spaced from a separating distance F.As below will further explaining, can change separating distance F to regulate the gain of sensor.In order to do like this, planar array 36 is connected on the positioning equipment 42, for example, has the conventional mechanical linear positioner of accurate locomitivity, this positioning equipment 42 can be regulated the position of planar array 36 with respect to plate 32, to change separating distance F as being indicated by arrow 43.With regard to hole array 34, each of hole 34 all has identical size and dimension since easy to manufacture generally be circular.In the example that shows, square formation geometric configuration is used for hole array 34, but can use other array geometry.

As shown in Figure 4, when wavefront 24 impinges upon on the plate 32, pass hole 34 with a slice or the part of the wavefront 24 of arrow 25 indication, to illuminate planar array 36.For first order, the generation image that is formed by each such wavefront sheet 25 is the positive shade of respective aperture 34.Yet diffraction is not to be taken place by the diameter D in each hole 34, the wavelength X of light source (being wavefront 24) and the mode that the separating distance F between plate 32 and planar array 36 determines.By positioning equipment 42 change value F, to regulate gain, as following further explanation according to concrete patient.

Note using solid panel or the film of making by the photochromics such as photoetching film, the function that provides by the plate 32 that has hole 34 also can be provided.Under such a case, hole array 34 replaces by clash into the shaping transmittance array of apertures that time thereon passes it when light.The remainder of a kind of like this plate or film is lighttight.The advantage that is realized by such an embodiment is, can easily make the transmittance aperture, with consistent with any desirable shape.

Produce each wavefront sheet 25 howsoever, the present invention measures the angular deflection amount of each the wavefront sheet 25 relevant with the wavefront sheet that is produced by plane wave front.This sees the most clearly in Fig. 4, and wherein the calibration of light or plane wave front generate the wavefront sheet (being orthogonal to plate 32) by arrow 112 expressions, and this wavefront sheet illuminates how much spots 114 on planar array 36.On the contrary, suppose the above-mentioned distorted wavefront of wavefront 24 expression, wavefront sheet 25 will present the angular deflection amount relevant with (calibration) wavefront sheet 112.Angular deflection causes that wavefront sheet 25 impinges upon how much spots 27 on the planar array 36, departs from (calibration) spot 114.According to the present invention, measure bias with respect to the centre of form 116 and 29 of spot 114 and 27 respectively.In two-dimensional plane array 36, the centre of form 29 (generally) all deflection on the x of array 36 and y direction.Thereby, provide by △ x/F and △ y/F respectively in the angular deflection on each of x and y direction.

In this most preferred embodiment, lens 220 and 224 are identical as described above.Yet, in some purposes, may wish to amplify or reduce wavefront at the Wavefront sensor place.This can be by using different focal lens 220 and 224 and thereby the conditioning equipment size realize.Estimate for eyes, the object plane of equipment should be ideally with can be tangent by the corneal plane that various devices are realized.Thereby, at each point at the object plane place of optical system 22 very near corresponding to the identical point on the cornea (but, lateral shift a little being arranged) because cornea is crooked.The plate 32 of wavefront analysis device 26 (or one-tenth image plane of any Wavefront sensor part) is positioned on the focal plane of lens 220.By this way, object plane always with the corresponding direction of wavefront image that occurs from cornea 126 on imaging on plate 32.This is real, and the optical path length between lens 220 and 224 is irrelevant.For this structure several advantages are arranged, one of them is the very good planar array that the light activated element that can buy from market is arranged, with 6 millimeters corresponding zones of central circular of imaging and cornea.To explain additional advantage now.

The purpose of plate 32 (or any Wavefront sensor part one-tenth image plane) is that a wavefront 24 is dispersed as at planar array 36 places each independently wavefront sheet of (according to the direction of propagation) measurement.Because in most preferred embodiment, image in object plane is not amplified or reduced to optical system 22, thus at the point at object plane place corresponding to identical point at the image plane place of optical system 22.For the Porro mirror 222 that is arranged on its " zero position ", the direction that wavefront 24 each sheet are advanced at the object plane place is replicated in the image plane place of wavefront analysis device 26 exactly.For example, if the wavefront sheet of a position in object plane with respect to advancing away from optical axis with 20 ° angle with optical axis perpendicular to object plane, then the wavefront sheet at the same position place is also advanced away from optical axis with 20 ° angle in image plane.

The people who notes myopia will produce a kind of like this wavefront, thereby will be to the centre convergence of array 36 by the wavefront sheet of plate 32 isolation.The hyperope will produce a kind of like this wavefront, thereby be dispersed by the wavefront sheet that plate 32 is isolated.Thereby the people with remarkable collimation error becomes and is difficult to estimate that (myopia) perhaps overflows (long sight) planar array 36 at planar array 36 places because the wavefront sheet can overlap.

In the present invention, three kinds of methods that are used for compensating this serious aberration are arranged.First method is to utilize a kind of Wavefront sensor with significantly little light activated element 38 and significantly big hole 34 (or any other transmission aperture).In this method, use the measurement that can proceed to each wavefront sheet of acceptable accuracy for the little value of F.Second method is, along optical axis plane of motion array 36 to change separating distance F for plate 32.For people, near plate 32 plane of orientation arrays 36, to keep projection wavefront sheet to separate well and on planar array 36 with serious aberration.For medium aberrations, energy plane of motion array 36 to increase the separating distance F for plate 32, is measured more accurately.The advantage that plane of motion array 36 changes for the separating distance F of plate 32 is, easily realizes wavefront analysis for any position.The third method that compensates serious aberration in the present invention is the optical path length that changes between lens 220 and 240.Mobile Porro mirror 222 will not influence the position that wavefront hits plate 32, but will change the angular deflection that projection wavefront sheet passes plate 32, i.e. △ x/F and △ y/F.Reduce the center that optical path length between lens 220 and 240 is tending towards the wavefront sheet is pulled to planar array 36, compensate long sight thus.The optical path length of increase between lens 220 and 240 will be tending towards the border extended of wavefront sheet to planar array 36, compensate for myopia thus.Changing the degree of the angular deflection relevant with each wavefront sheet, is that it leaves the distance of optical axis and the linear function that Porro mirror 222 leaves the amount of movement of its zero position.

In order to determine to impinge upon the centre of form of the hot spot on the array 36 exactly, must provide the fine structure of element 38 with respect to spot size.In other words, each luminous point must cover a plurality of elements 38.In this most preferred embodiment,, the element of unique quantity is distributed to each hole 34 in order clearly to determine the centre of form of each spot with respect to the spot that causes by another one hole 34.In Fig. 5, indicate " range of distribution " by coarse grid line 39.Should be appreciated that gridline 39 is not the actual physics border between the element 38, but represent unique appointed area of comprising a plurality of elements 38 to show simply.Can utilize other centre of form countermeasures that do not need array 36 to divide like this.

Because Wavefront sensor of the present invention does not focus on minimum to each wavefront sheet in the surface of array 36, thus illuminate the element 38 of larger amt by each how much spot, thus can be to determine the centre of form of each spot than previously possible more high precision.

By means of the wavefront analysis device that replaces plate 32 (Fig. 3) with a two-dimensional array 33 of identical spherical lenslet, also can implement the present invention, as shown in Figure 6.In order to realize advantage of the present invention, array 33 is located like this by positioning equipment 42, thereby separating distance F is independent of the focal plane focal length F of definition by the array 33 of dotted line 35 expressions.In other words, each the wavefront sheet (for example the wavefront sheet 37) that passes the sub-aperture of array 33 reduces on size (for example diameter), if but needn't equal focal distance f as separating distance F then can occur, 36 places take minimum at array.Thereby, in practice, array 33 is positioned to for the sufficient density on planar array 36 concentrates on the light in each wavefront sheet on the zone, and still illuminates a large number of element 38 (as described above), so that determine the deflection of the spot centre of form with full accuracy.

With the structure-irrelevant of Wavefront sensor, processor 40 calculates each bidimensional centre of form of each spot that is produced by wavefront 24.For the bidimensional centre of form side-play amount (with respect to the centre of form of calibration spots) of each appointed area relevant with respective aperture 34 (or sub-aperture of array 33) divided by separating distance F, produce a slope local matrix of wavefront, i.e. (the x at 34 centers in the hole, y) the δ W (x at coordinate place, y)/and δ x and δ W (x, y)/δ y.For simplicity, these respectively by P (x, y)=δ W (x, y)/δ x and Q (x, y)=δ W (x, y)/δ y indication.

There is the several different methods that is used for using partial derivative data computation original (distortion) wavefront.A kind of receivable method is the method for being used in above-mentioned paper by Liang etc., wherein uses Zernike polynomial approximation wavefront.This is a kind of standard analytical techniques of describing in many pieces of optical articles, as " optical principle " Pergamon Press at M.Born and E.Wolf etc., and Oxford, England is in 1964.By example, Zernike polynomial expression method will be discussed here.Yet, should be appreciated that other mathematical methods also can be used in the approximate distorted wavefront.

Speak briefly, (x y) is expressed as each polynomial weighted sum wavefront W $W(x,y)=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{C}_i{Z}_i(x,y)--\left(4\right)$

C wherein _iBe weighting coefficient, and Z _i(x y) is high Zernike polynomial expression to certain rank.About the upper limit n of summation is to be used for the polynomial quantity of Zernike of approximate true wavefront, promptly high-order, function.If the high-order that m is to use, so

n=(m+1)(m+2)／2 (5)

At many pieces of optical articles, as the above-mentioned books of Born and Wolf, the middle polynomial derivation of Zernike of having described high extremely any rank n.

To explain a kind of possibility method of determining that the spot centre of form and Zernike weighting coefficient calculate now.In the direction of the unit normal of each 34 center, hole the centre of form based on the spot on element 38.Because each spot will illuminate a plurality of elements to change brightness, so can use standard amplitude weighting centroid calculation to obtain the center of each spot.Each centre of form must measure twice, once is used for vertical collimated light, and is used for the wavefront that will analyze once more.Certainly, the institute of imaging simultaneously spottiness between each exposure period.

Can use and repeatedly expose inappropriate eye alignment or the eye motion of checking between each time exposure period.If the eye motion between exposure period can not be by obtaining repeatedly to expose successfully analysis, system 10 can enlarge by the interpolation of an eye tracker 25 so.A kind of may the placement of eye tracker 25 is illustrated among Fig. 2.Yet, should be appreciated that, can be placed on other places in the system 10 to eye tracker 25.A kind of such eye tracker is at above-mentioned U.S. Patent Application Serial Number No.08/232, and is open in 615.By this way, even during limited eye motion amount, also can carry out wavefront analysis.

The single calibration exposes the relative sensitivity that also can be used for determining each element.This is carrying out in collimated light uniformly by means of removing plate 32.Write down the response of each element then.

For each transmittance aperture (for example the hole 34), the centre of form under the collimation situation is used from the effect of the special-purpose initial point in concrete hole.Determine by the direction of the wave surface corresponding for the skew (as observed this coordinate system) that each hole is caused by wavefront 24 from " initial point " to the centre of form with this hole.(m, ((m, n) the P value of the individual centre of form is to be used for the so for m, n) the x component of the individual centre of form, and F is that plate separates n) to be the if △ is x

P(m，n)=δx(m，n)／δz=△x(m，n)／F (6)

The corresponding expression formula that is used for Q is

Q(m，n)=δy(m，n)／δz=△y(m，n)／F (7)

Thereby, each P (m, n) and Q (m, n) expression for each hole 34 (x, y) (x is y) with respect to the partial derivative of x and y for coordinate W.M rank Zernike for original wavefront is approximate, uses experiment definite P and Q then in following formula, to press the suitable C of following calculating _iWeighting coefficient $P(m,n)=\frac{\mathrm{\δW}(x,y)}{\mathrm{\δx}}=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{C}_i\frac{\mathrm{\δ}{Z}_i(x,y)}{\mathrm{\δx}}--\left(8\right)$ $Q(m,n)=\frac{\mathrm{\δW}(x,y)}{\mathrm{\δy}}=\underset{i=0}{\overset{n}{\mathrm{\Σ}}}{C}_i\frac{\mathrm{\δ}{Z}_i(x,y)}{\mathrm{\δy}}--\left(9\right)$

(m n)/the error minimum of the actual wavefront slope that δ zach makes left-hand side in above formula between being similar to the Zernike of right-hand side, can obtain being used for the optimum value of weighting coefficient by using least square approximation.

At a kind of calculating centre of form (x _c, y _c) possible method in, the reserved area or the (i of its arrays 36 distributed in each hole 34 _{M, m}± △ i, j _{M, m}± △ j).This square of a plurality of light activated elements is big must to be enough to make the adjacent holes image to be invaded never, and comprises all illuminations from this hole.This square comprises j element of 4 △ i* △.

If specified arrays 36

c _{K, l}=(x _c(i, j), y _c(i, j)), k, l=0 ... 2 △ l, △ j, and be △ x=△ y=d about the gap at center, the element responds of measurement be V (k, l) and relative response is R (k, 1), so as i, the x component x of j function _cBe x _c(i, j)=[Σ _{K, l}V (k, l) * R (k, l) * d*k]/[Σ _{K, l}V (k, l) * R (k, l)] (10)

And as i, the y component y of j function _cBe y _c(i, j)=[Σ _{K, l}V (k, l) * R (k, l) * d*l]/[Σ _{K, l}V (k, l) * R (k, l)] (11)

Then, if (x _C0(i, j), y _C0(i, j)) is for (i, j) " the initial point centre of form " in hole promptly forms in vertical collimated light, and (x _Cw(i, j), y _Cw(i, j)) is the corresponding centre of form of obtaining for the wavefront that will measure, so relatively centre of form skew (x _Cr(i, j), y _Cr(i, j)) obtains by following

(x _cr(i，j)=x _cw(i，j)-x _c0(i，j) (12)

(y _cr(i，j)=y _cw(i，j)-y _c0(i，j) (13)

Value P (i, j) and Q (i, j) definite by following formula

P(i，j)=x _cr(i，j)／F (14)

With

Q(i，j)=y _cr(i，j)／F (15)

Secondly use surperficial partial derivative P for the hole center array of plate 32 (i, j) and Q (i j) calculates description original wavefront W (x, suitable Zernike polynomial expression weighting coefficient y).This passes through the interpretation for 7 * 7 quadrate arrays in hole 34 now.Yet, should be appreciated that, can use the hole array of other size and dimensions.

At first, by following formation one 1 * 98 matrix (being column matrix) PQ (k)

PQ(k)=P(7i+j)，j=0…6，i=0…6，k=0…48 (16)

PQ(k)=Q(7i+j)，j=0…6，i=0…6，k=49…98 (17)

Make j for each i circulation, i.e. PQ (18)=P (2,5).

Matrix PQ multiply by transition matrix TM with by the following Matrix C that obtains from the left side

c=TM*PQ (18)

Wherein TM 98 widely takes advantage of 14 high matrixes, and C is 1 wide 14 high matrix or the column vectors of taking advantage of.C is a Matrix C _kK=1 ..., 14, thereby for least squares error,

w(x，y)=Σ _kC _k*Z _k(x，y) (19)

And for giving set aperture, for example 6 millimeters pupil aperture calculates TM.

Function Z in formula (19) _k(x y) is the Zernike polynomial expression.There is not standard convention about its sequence.Thereby, for consistance, importantly, use identical sequence to be produced as the set C that derivational matrix TM selects _kThey occur in the group of phase same order, and this is the best result amount in group, and the item sum in single order increases with exponent number.For example, in quadravalence is analyzed, use up to 4 and comprise 4 exponent number (less Z ₀The individual event on-rank 0 is a constant 1, is described in the reference position of Z direction group).Because wavefront 24 is along Z (with the light velocity) motion,, and can ignore this so this " piston item " only is described in any skew among the Z.5 initial rank (0,1 ..., 4) and comprise 15 functions that comprise the piston item.

Thereby, in the example that shows, calculate C _k14 values as 14 polynomial coefficients of Zernike.By example, a kind of this rank that are used for calculating TM provide in table 1, and it comprises Zernike polynomial expression and its partial derivative.

Table 1

Zernike (x, y) polynomial expression expansion by rank 4

Order of a polynomial 0

z(0) +1

dz(0)／dx?0．0

dz(0)／dy?0．0

Order of a polynomial 1

z(1) +y

dz(1)／dx?0．0

dz(1)／dy?+1

z(2) +x

dz(2)／dx?+1

dz(2)／dy?0．0

Order of a polynomial 2

z(3) -1+2y ²+2x ²

dz(3)/dx +4x

dz(3)/dy +4y

z(4) +2xy

dz(4)/dx +2y

dz(4)/dy +2x

z(5) -y ²+x ²

dz(5)/dx +2x

dz(5)/dy -2y

Order of a polynomial 3

z(6) -2y+3y ³+3x ²y

dz(6)/dx +6xy

dz(6)/dy -2+9y ²+3x ²

z(7) -2x+3xy ²+3x ³

dz(7)/dx -2+3y ²+9x ²

dz(7)/dy +6xy

z(8) -y ³+3x ²y

dz(8)/dx +6xy

dz(8)/dy -3y ²+3x ²

z(9) -3xy ²+x ³

dz(9)/dx -3y ²+3x ²

dz(9)/dy -6xy

Order of a polynomial 4

z(10) +1-6y ²+6y ⁴-6x ²+12x ²y ²+6x ⁴

dz(10)/dx -12x+24xy ²+24x ³

dz(10)/dy -12y+24y ³+24x ²y

z(11) -6xy+8xy ³+8x ³y

dz(11)/dx -6y+8y ³+24x ²y

dz(11)/dy -6x+24xy ²+8x ³

z(12) +3y ²-4y ⁴-3x ²+4x ⁴

dz(12)/dx -6x+16x ³

dz(12)/dy +6y-16y ³

z(13) -4xy ³+4x ³y

dz(13)/dx -4y ³+12x ²y

dz(13)/dy -12xy ²+4x ³

z(14) +y4-6x2y ²+x ⁴

dz(14)/dx -12xy ²+4x ³

dz(14)/dy +4y ³-12x ²y

C in the polynomial selection regulation formula of ordering Zernike (19) _kExplanation, therefore and be defined in the TM matrix all order.Therefore, must after selecting, calculate the TM matrix.Below explanation is used for the generation of the TM matrix of case illustrated.

Notice that the quadravalence analysis is an example, rather than unique possibility.The Zernike that can proceed to any rank analyzes.In general, rank are high more, and the result on test point is accurate more.Yet the accurate fitting of a polynomial on test point is not necessarily wished.This seemingly closing has typical interference characteristic: unless the surface itself is not to be higher than the accurate polynomial expression that is used for the surface fitting rank by chance, otherwise the accurate match at all points of separation place causes the thrass between match point.In other words, in polynomial expression surface match, can produce the average fit of difference for general purpose function in the accurate match at limited quantity point place.For the ophthalmic applications of said system, computer simulation proposes six rank Zernike analysis can produce best result.

By from Zernike is approximate, deducting a constant, realize simply re-constructing △ z (x, y) the optical path difference information calculated from the Zernike of wavefront.The value of constant will depend on △ z (x, expected characteristics y).According to proofreading and correct the method (for example, laser ablation, lens interpolation etc.) that aberration is selected, for example can wish △ z (x, maximum y), on average or minimum value be set to equal zero.

Explain the generation of transition matrix TM now for the case illustrated of 7 * 7 array holes in the plate 32.At each point (x _i, y _j) locate, the tangent of normal component is P (x _i, y _j) and Q (x _i, y _j), wherein

P(x _i，y _j)=δW(x _i，y _j)／δx (20)

With

Q(x _i，y _j)=δW(x _i，y _j)／δy (21)

These are combined with formula (11),

P(x _i，y _j)=∑ _kC _kδW(x _i，y _j)／δx (22)

With

Q(x _i，y _j)=∑ _kCkδW(x _i，y _j)／δy (23)

Each can be applicable to 49 kinds of (i, j) combinations.These are combined into is 98 single-row vectorial PQ that element is high, for example one 98 * 1 matrix.Define two Matrix C _k(14 height * 1 is wide) and M _{K, (ij)}(14 wide * 98 height)

(M _k，(i，j))=δZ _k(x _i，y _j)／δx；δZ _k(x _i，y _j)／δy (24)

Wherein the x derivative be initial 49 the row and the y derivative be last 49 the row.Then, can be rewritten as Matrix Formula to formula (19)

(PQ)=(M)(C) (25)

Wherein top 49 row of M are δ W (x _i, y _i)/δ y.

According to the Zernike coefficient on the surface that is used for being described by the array of 14 C, the expression in the formula (25) provides quadrature component.These are accurately, but do not guarantee that actual whole surface energy is by such coefficient arrays description.Thereby, if supposition is described in the receivable tolerance limit, promptly allow remaining error after least squares error is determined, can consider formula (26) so, so that impliedly define column vector C according to all known math matrix M and the vectorial PQ of measurement.The method that realizes this scheme under minimal condition is as follows.

At first, formula (25) on the left side multiply by the transposition M of M ^TThereby,

(M ^T)(PQ)=(M ^T)(M)(C)=(S)(C) (26)

Wherein

S=M ^TM (27)

Being square and symmetric matrix, for example is dimension 14 * 14 (for each element, 98 sum of products).A kind of like this matrix has inverse matrix, unless its determinant of coefficient is zero.Because this is separately based on the Zernike polynomial expression, and they are independent of each other, so determinant is a non-zero, thereby define an inverse matrix S ^-1Secondly, formula (25) on the left side multiply by S ^-1To produce

(8 ^-1)(M ^T)(PQ)=(s ^-1)(8)(C)=(I)(C)=C (28)

Then, mathematics transition matrix (being independent of measurement) is

(TM)=C(S ^-1)(M ^T) (29)

And can produce " best fitted " array of the C of self-metering PQ by simple matrix multiple

(c)=(TM)(PQ) (30)

In order clearly to estimate eyes,, wavefront 24 must be incident on simultaneously on the planar array 36 because illuminating institute's spottiness of planar array 36.Speed realizes by pulsation or switch laser source (being laser instrument 12), thereby the duration of pulse is less than the saccade interval of eyes, promptly several milliseconds.Alternatively, it is continuous to keep lasing light emitter, and can switch wavefront 24, seeming resembles wavefront pulse less than the duration of eyes jerking movement.Thereby as shown in Figure 2, shutter 50 can be positioned in the path of laser beam 18 before eyes 120, perhaps in the path of wavefront 24 before wavefront analysis device 26.

The enforcement of the present invention that is suitable for clinical use schematically illustrates in Fig. 7, and generally with label 11 indications.Similarly label be used for describing with respect to system 10 in those components identical described above.Thereby, do not further describe similar elements and its function.

A double color laser optical splitter 52 is inserted between beam splitter 20 and the optical system 22, and the fixed target optical system 60 and the viewing optical system 70 of optical fractionation are incorporated in the system 11 each other by 50/50 beam splitter 54 with handle.On function, the fixed target optical system provides the visible light of target shape for eyes 120.The visible light that is produced by fixed target optical system 60 is reflected by double color laser optical splitter 50, and direction is by optical system 22.

Should be appreciated that fixed target optical system 60 can be implemented in every way.By example, represent such embodiment, and comprise a visible light source 61, light diffuser 62, target 63, field stop 64, lens 65 and an aperture 66.Light source 61 and light diffuser 62 are used to provide the even illumination of fixed target 63.Field stop 64, lens 65, and aperture 66 contact optical systems 22 use, present to (patient) eyes 120 with sharp image fixed target.

On function, viewing optical system 70 allows the technician to observe and conclusive evidence eyes estimation procedure.Although the various enforcements of viewing optical system 70 are possible, represent a kind of such enforcement by example.In Fig. 7, viewing optical system 70 comprises field-of-view lens 71, lens 72, aperture 73, lens 74, reaches gamma camera 75.A ring illumination lamp 80 is placed on the front of eyes 120, so that illuminate eyes in order to observe and/or take purpose.

From the output of wavefront analysis device 26, for example the Zernike of formula (19) launches, and can use in every way.For example, can use output to come continuously or monitor periodically the carrying out or the effect of ophthalmic procedures.This output also can be used for producing the optical correction for eyes 120.Optical correction makes wavefront 24 seem and is approximately plane wave.As mentioned above, optical correction can be implemented in every way.Under each situation, the output of wavefront analysis device 26 is input to a processor 90, and processor 90 launches the Zernike of formula (19) to convert to the form that is suitable for as one of possibility optical correction enforcement.(function of processor 90 also can be implemented at processor 40 places of wavefront analysis device 26).

Processor 90 can use some from the Zernike coefficient of the expansion of formula (19), produces the standard ball cylinder correction that is used for lens grinding machine 92, to produce conventional optical lens, for example is used for the lens, contact lens of glasses etc.Processor 90 also can subtract 1 to the refractive index that the Zernike that the aberration wavefront is arranged re-constructs divided by cornea 126, to calculate on cornea in each corresponding (x, y) amount of corneal material of position ablation.The amount of corneal material in each position is input to a laser beam delivery system, and this system generally has eye tracking ability 94, as at above-mentioned U.S. Patent Application Serial Number No.08/232, as described in 615.Laser beam is carried and eye tracker 94 be placed to the optical axis of system 11 in line.The eye tracker of this element partly allows the unnecessary eye motion of system's 11 responses.Laser beam is carried and eye tracker 94 generally focuses on cornea 126 or eyes 120 places to the short pulse of ablative laser light or " shooting ", to remove the material of specific thickness t in each position.This schematically illustrates in Fig. 8, and wherein the not correction surface of cornea 126 is indicated with label 126A, and the correction surface of cornea 126 is indicated by label 126B after ablating.

According to the present invention, stride across the aperture of tested cornea, for example 6 millimeters circles that during eyes are measured the pupil of eyes are diffused into are stipulated recession thickness t.Outside predetermined processing circle, can add the mixed zone that reduces that part ablates, reducing the acute variation of cornea bending, and therefore alleviate decline.Laser beam delivery system 94 is removed thickness t, to realize optical correction, i.e. anterior corneal surface 126B of Jiao Zhenging.Notice that optical correction is not relevant with final cornea profile, but remove corneal material, consider the optical correction of all eyepiece aberrations of eyes with realization.This is important, because the surface configuration of cornea can be independent of the correction of requirement, because the vision of eyes depends on a plurality of factors except that the cornea bending.Therefore, being used for the best cornea surface topography of optimum visual can be away from rule aspect following: it must compensate other surperficial errors of eyes.Thereby obviously the present invention can be used to provide the anterior corneal surface correction except that conventional sphere and/or cylinder correction.

Advantage of the present invention has a plurality of.Provide a kind of fully objectively method that is used for the measuring eyepiece aberration.This method is effective for the defects of vision of wide region.Thereby the present invention has very big practicality in various clinical applications.For example, the Zernike coefficient of calculating can be used for producing the complete objective lens arrangement or the corneal correction that can realize by means of laser ablation.In addition, each of Wavefront sensor embodiment provides the high accuracy that is better than prior art with respect to measuring wavefront deflection.And, become separating distance between image plane and the light activated element planar array by being adjusted in sensor simply, can be according to this Wavefront sensor of gain-adjusted.

Objective measurement of the present invention also will be found very big practicality for a large amount of purposes that wherein " patient " can not provide the feedback that is required by conventional eyes diagnosis.For example, the present invention can be used for estimating not have any patient's who shows communication skill eyes, as the optical system of baby, animal, dead sample and any construction, because the present invention is need be from the objective analysis of any estimation of " object ".What all were essential is that the object eyes are suitably located, thereby can obtain the suitable optical access to eyes.

It is unique identification field that the present invention also can be used in the Zernike coefficient that determine every eyes.So, the present invention is that very big practicality can be found in any other useful field in enforcement field, credit card/bank safety or positive identification.

Although described the present invention, multiple conspicuous change and modification are arranged according to of the present invention telling about for the professional who is familiar with present technique with respect to its specific embodiment.Therefore should be appreciated that, in the scope of appended claims book, except that specifically described, can implement the present invention.

As new by what the United States Patent (USP) certificate was protected be with requirement hope:

Claims (50)

1. system comprises:

An energy source is used for producing radiation laser beam;

Optical system, be arranged in the path of described light beam, be used for guiding described light beam by making a Focused Optical system of its rear diffusion reflector effect, wherein said light beam is as before passing through the radiated wave of described Focused Optical system, the reflected back diffusely from described rear portion, impinging upon on the described optical system, optical system by with impinge upon described optical system on the described wavefront of direct corresponding projection of described wavefront;

A wavefront analysis device is arranged in from the path of the described wavefront of described optical system projection, and the distortion that is used for calculating wavefront is estimated as the aberration of described Focused Optical system.

2. system according to claim 1, wherein said energy source comprises:

A collimation laser device is used for producing collimation laser light; And

An iris ring is arranged in the path of described collimation laser light throwing the collimation heart portion of described collimation laser light, and wherein said collimation heart portion has diameter at about 0.5 millimeter described radiation laser beam to about 4.5 millimeters scopes.

3. system according to claim 1, wherein said radiation is optical radiation, and wherein said Focused Optical system comprises:

One first lens remain in one first fixed position in the path of described light beam and described wavefront;

One second lens remain in one second fixed position in the path of described light beam and described wavefront; And

A kind of arrangement of optical element, be arranged in the path of described light beam and described wavefront between described first lens and described second lens, the described arrangement of optical element is adjustable, so that change the optical path length between described first lens and described second lens.

4. system according to claim 3, wherein said wavefront analysis device comprises a Wavefront sensor that is used for described wavefront is divided into a plurality of optical radiation light beams, the focal plane of wherein said first lens is at described Wavefront sensor place, and a focal plane of wherein said second lens is at the object plane place of described Focused Optical system.

5. system according to claim 3, wherein said Focused Optical system is that eyes and wherein said wavefront analysis device comprise a Wavefront sensor that is used for described wavefront is divided into a plurality of optical radiation light beams, the focal plane of wherein said first lens is at described Wavefront sensor place, and the focal plane of wherein said second lens is at the pupil place of described eyes.

6. system according to claim 1, wherein said wavefront analysis device is a Hartmann-Shack wavefront analysis device.

7. system according to claim 1, wherein said radiation is optical radiation, and wherein said wavefront analysis device comprises:

A plate is lighttight except that the array in the transmittance aperture that allows bump light therefrom to pass, and described plate is arranged in the path of described wavefront, and all parts of wherein said wavefront are passed the described array in transmittance aperture;

A planar array of light activated element, be parallel to that described plate is arranged and separate the distance of a selection with described plate, each of described part of wherein passing the described wavefront of one of described array in transmittance aperture illuminates the geometric configuration of covering from unique a plurality of elements of the described planar array of element; And

A processor is connected on the described planar array of element, is used for according to the described distortion of the centroid calculation of each described geometric configuration.

8. system according to claim 7, wherein each the transmittance aperture in the described array in transmittance aperture has the size that is equal to.

9. system according to claim 7, wherein each the transmittance aperture in the described array in transmittance aperture is circular.

10. system according to claim 7, wherein the described array in transmittance aperture is a quadrate array.

11. system according to claim 7 further comprises the device of the described chosen distance between the described planar array that is used for being adjusted in described plate and element.

12. system according to claim 11, wherein said radiation is optical radiation, and wherein said Focused Optical system comprises:

One first lens remain in one first fixed position in the path of described light beam and described wavefront;

One second lens remain in one second fixed position in the path of described light beam and described wavefront; And

A kind of arrangement of optical element, be arranged in the path of described light beam and described wavefront between described first lens and described second lens, the described arrangement of optical element is adjustable, so that change the optical path length between described first lens and described second lens.

13. system according to claim 1, wherein said radiation is optical radiation, and wherein said wavefront analysis device comprises:

A two-dimensional array of spherical lenslet, limit a focal plane, this focal plane is away from focal length of described two-dimensional array of spherical lenslet, the described two-dimensional array of spherical lenslet is arranged in the path of described wavefront, and all parts of wherein said wavefront are passed the described two-dimensional array of spherical lenslet;

A planar array of light activated element, the described two-dimensional array that is parallel to spherical lenslet arranges and is spaced from a chosen distance that is independent of described focal length, and each of described part of described wavefront of wherein passing the described two-dimensional array of spherical lenslet illuminates the geometric configuration of covering from unique a plurality of elements of the described planar array of element; And

A processor is connected on the described planar array of CCD element, is used for according to the described distortion of the centroid calculation of each described geometric configuration.

14. system according to claim 13 further comprises the device of the described chosen distance between the described planar array of the described two-dimensional array that is used for being adjusted in spherical lenslet and element.

15. system according to claim 14, wherein said optical system comprises:

One first lens remain in one first fixed position in the path of described light beam and described wavefront;

One second lens remain in one second fixed position in the path of described light beam and described wavefront; And

A kind of arrangement of optical element, be arranged in the path of described light beam and described wavefront between described first lens and described second lens, the described arrangement of optical element is adjustable, so that change the optical path length between described first lens and described second lens.

16. system according to claim 1, wherein said Focused Optical system is any eyes, and further comprises the device that is used for making the described light beam conduct duration pulse generation littler than the jerking movement interval of described eyes.

17. system according to claim 1, wherein said Focused Optical system is any eyes, and further comprise be used for making described wavefront as than the little at interval duration pulse of the jerking movement of described eyes to described wavefront analysis device device shown.

18. system according to claim 1, wherein said Focused Optical system is any eyes, and comprise that further a shape that is used for according to target produces the fixed target generator of visible light, described fixed target generator is so arranged, thereby described visible light guides through described optical system, and wherein said visible luminous energy is seen by described eyes.

19. system according to claim 1 further comprises a converter that is used for described distortion is converted to optical correction, if this converter is placed in the path of described wavefront, described wavefront is seemed be approximately plane wave.

20. system according to claim 19, wherein said converter is transformed into described distortion on the lens arrangement, and wherein realizes described optical correction according to described lens arrangement by lens.

21. system according to claim 19, wherein said optical system is eyes, and wherein said converter described distortion is converted to will be from the amount of the corneal material of the complex geometric shapes of described eyes ablation, described system further comprises a laser beam delivery system, this laser beam delivery system is used for shining described eyes by means of the ablate wavelength of described corneal material and a plurality of minor diameter laser beam pulses of power, wherein realizes described optical correction by the corneal material of removing described amount.

22. system according to claim 21, wherein said laser beam delivery system comprises that further one is used for monitoring described eye motion and is used for regulating eye tracker with the position of the corresponding described a plurality of minor diameter laser beam pulses of described motion.

23. system according to claim 19, wherein said optical system is eyes, and wherein said converter changes the regulation that described distortion converts the bending of described eyes anterior corneal surface to, and, realize described optical correction wherein by changing the described anterior corneal surface bending that forms described eyes again according to described regulation.

24. system according to claim 1, wherein said optical system are eyes, and further comprise an eye tracker that is used for monitoring the motion of described eyes.

25. an optical wave-front sensor comprises:

A plate is lighttight except that the array in the transmittance aperture that allows bump light therefrom to pass, and described plate is arranged in the path of described wavefront, and all parts of wherein said optical wavefront are passed the described array in transmittance aperture; And

A planar array of light activated element, be parallel to that described plate is arranged and separate the distance of a selection with described plate, each of described part of wherein passing the described wavefront of one of described array in transmittance aperture illuminates the geometric configuration of covering from unique a plurality of elements of the described planar array of element.

26. optical wave-front sensor according to claim 25, wherein each the transmittance aperture in the described array in transmittance aperture has the size that is equal to.

27. optical wave-front sensor according to claim 25, wherein each the transmittance aperture in the described array in transmittance aperture is circular.

28. optical wave-front sensor according to claim 25, wherein the described array in transmittance aperture is a quadrate array.

29. optical wave-front sensor according to claim 25 further comprises the device of the described chosen distance between the described planar array that is used for being adjusted in described plate and element.

30. optical wave-front sensor according to claim 25 further comprises on the described planar array that is connected to element, is used for determining the processor of the centre of form of each described geometric configuration.

31. a method comprises step:

Produce an optical radiation light beam;

By means of Focused Optical system described light beam is focused in the eyes, to be a focused spot that forms the limited image of nearly diffraction at place, described eye retina rear portion to described light beam imaging, wherein said beam spread ground returns from retinal reflex, before passing through the radiated wave of described eyes;

Allow described wavefront to impinge upon on the described Focused Optical system;

By means of described Focused Optical system, by with impinge upon described Focused Optical system on the described wavefront of direct corresponding projection of described wavefront; And

Use is arranged in a wavefront analysis device from the path of the described wavefront of described Focused Optical system projection, calculates and the relevant distortion of described wavefront of throwing from described Focused Optical system.

32. method according to claim 31, wherein said generation step comprises:

Produce collimation laser light; And

Select one of described collimation laser light collimation heart portion, as having diameter at about 0.5 millimeter described optical radiation light beam to about 4.5 millimeters scopes.

33. method according to claim 31, wherein said focus steps comprises step:

One first lens are fixed in the primary importance in the path of described light beam and described wavefront;

One second lens are fixed in the second place in the path of described light beam and described wavefront; And

A kind of arrangement of optical element is positioned in the path of described light beam and described wavefront between described first lens and described second lens; And

Regulate the position of the described arrangement of optical element, so that change the optical path length between described first lens and described second lens.

34. method according to claim 33, wherein said wavefront analysis device comprises a Wavefront sensor that is used for described wavefront is divided into a plurality of optical radiation light beams, the described step of wherein fixing described first lens comprises the step that the focal plane of described first lens is arranged in described Wavefront sensor place, reaches the described step of wherein fixing described second lens and comprises the step that the focal plane of described second lens is arranged in the pupil place of described eyes.

35. method according to claim 31, wherein said wavefront analysis device comprises: a plate, except that the array in the transmittance aperture that allows bump light therefrom to pass is lighttight, described plate is arranged in the path of described wavefront, and all parts of wherein said wavefront are passed the described array in transmittance aperture; A planar array with light activated element, be parallel to that described plate is arranged and separate the distance of a selection with described plate, each of described part of wherein passing the described wavefront of one of described array in transmittance aperture illuminates the geometric configuration of covering from unique a plurality of elements of the described planar array of element, and described method further comprises regulates the step of described chosen distance with the gain of regulating described wavefront analysis device.

36. method according to claim 35, wherein said focus steps comprises step:

One first lens are fixed in the primary importance in the path of described light beam and described wavefront;

One second lens are fixed in the second place in the path of described light beam and described wavefront; And

A kind of arrangement of optical element is positioned in the path of described laser beam and described wavefront between described first lens and described second lens; And

Regulate the position of the described arrangement of optical element, so that change the optical path length between described first lens and described second lens.

37. method according to claim 31, wherein said wavefront analysis device comprises: a two-dimensional array of spherical lenslet, limit a focal plane, this focal plane is away from focal length of described two-dimensional array of spherical lenslet, the described two-dimensional array of spherical lenslet is arranged in the path of described wavefront, and all parts of wherein said wavefront are passed the described two-dimensional array of spherical lenslet; A planar array with light activated element, a chosen distance that is not equal to described focal length is arranged and be spaced to the described two-dimensional array that is parallel to spherical lenslet, each of described part of described wavefront of wherein passing the described two-dimensional array of spherical lenslet illuminates the geometric configuration of covering from unique a plurality of elements of the described planar array of element, the described planar array of element has the hole array that passes wherein, and described method further comprises regulates the step of described chosen distance with the gain of regulating described wavefront analysis device.

38. according to the described method of claim 37, wherein said focus steps comprises step:

One first lens are fixed in the primary importance in the path of described light beam and described wavefront;

One second lens are fixed in the second place in the path of described light beam and described wavefront; And

A kind of arrangement of optical element is positioned in the path of described light beam and described wavefront between described first lens and described second lens; And

Regulate the position of the described arrangement of optical element, so that change the optical path length between described first lens and described second lens.

39. method according to claim 31 further comprises the step of the described light beam that opens circuit, thus pilot pulse by described Focused Optical system, described pulse has the duration littler at interval than the jerking movement of described eyes.

40. method according to claim 31 comprises that further the step of the described wavefront that opens circuit, described wavefront show to described wavefront analysis device, as the duration pulse littler at interval than the jerking movement of described eyes.

41. method according to claim 31 further comprises step:

Shape according to target produces visible light; With

Guide described visible light by described Focused Optical system, wherein said visible luminous energy is seen by described eyes.

42. method according to claim 31 further comprises the step that described distortion is converted to optical correction, if this optical correction is placed in the path of described wavefront, described wavefront is seemed be approximately plane wave.

43. according to the described method of claim 42, wherein said optical correction is in the lens mode.

44. according to the described method of claim 42, wherein said optical correction is in the mode from described eyes ablation amount of corneal material.

45. according to the described method of claim 42, wherein said optical correction is the mode with the bending of the described eyes anterior corneal surface of provisioning change.

46. method according to claim 31 further comprises the step that the pupil of described eyes is diffused into the size that is issued at the low-light (level) environment, realizes described diffusing step before described focusing, permission and projection step.

47. method according to claim 31 further comprises step:

On described eyes, carry out ophthalmic procedures; And

After described ophthalmic procedures has begun, the step of carrying out described generation, focusing, permission, projection and calculating at least once, to monitor of the influence of described ophthalmic procedures to described eyes.

48. method according to claim 31, wherein said calculation procedure comprise the step of calculating the Zernike coefficient relevant with described distortion.

49. a method comprises step:

Optical access to the eyes of the object that can not clearly communicate by letter is provided;

Produce an optical radiation light beam;

By means of Focused Optical system described light beam is focused in the described eyes, to be a focused spot that forms the limited image of nearly diffraction at place, described eye retina rear portion to described light beam imaging, wherein said beam spread ground returns from retinal reflex, before passing through the radiated wave of described eyes;

Allow described wavefront to impinge upon on the described Focused Optical system;

By means of described Focused Optical system, by with impinge upon described Focused Optical system on the described wavefront of direct corresponding projection of described wavefront; And

Use is arranged in a wavefront analysis device from the path of the described wavefront of described Focused Optical system projection, calculates and the relevant distortion of described wavefront of throwing from described Focused Optical system.

50. a method of proofreading and correct the ocular vision defective comprises step:

The distortion of the wavefront of the light of the definition initial point scattered reflection of measurement from the described eye retina, described distortion indication should be removed corneal material in accurate location on described eyes anterior corneal surface amount is to eliminate described distortion approx; And

In the ablate described amount of described eyes corneal material of described accurate location.

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