CN1206514C - Wavefront sensor - Google Patents

Abstract

The present invention discloses an integrated hartmann diaphragm wavefront sensor manufactured by a micro-optical technology or a binary optical technology, which is an integrated chip composed of a microlens array and a back irradiating CCD detector, wherein more than 2*2 pixels are irradiated in a pixel region of the photosensitive target surface of the CCD detector by sub lens units of the microlens array. The structure of the present invention ensures that the relative position between the microlens array and the CCD detector is completely fixed; a complicated coupling installation and modulation technology is avoided, the structure is simple and stable, and the influence of vibration on the precision of the sensor is reduced; the present invention can work under the severe conditions and can be used for self adaptive optical systems.

Description

A kind of Wavefront sensor

Technical field

The present invention relates to a kind of Wavefront sensor, relate in particular to a kind of Hartmann wave front sensor of new construction.Hartmann wave front sensor is a kind of dynamic wavefront detecting instrument.Hartmann wave front sensor adopts aperture segmentation element and concentrating element that incident wavefront is divided into sub-aperture, again it is focused on the ccd detector photosensitive target surface, form spot array, by computing machine the hot spot signal that ccd detector receives is handled, obtained the corrugated error signal of incident wavefront.

Background technology

Existing Hartmann wave front sensor adopts the structure of microlens array and ccd detector coupling usually.34 21 phases of volume of " applied optics " periodical that July 20 nineteen ninety-five, U.S. optics association published the 4186th page the disclosed a kind of Hartmann wave front sensor of " key property of a Hartmann and shear interference Wavefront sensor relatively " literary composition, promptly adopt this structure, being coupled by mechanical mechanism by microlens array and ccd detector constitutes.(list of references: Byron M.Welsh, Brent L.Ellerbroek, Micheal C.Roggemann, Timothy L.Pennington " Fundamentalperformance comparison of a Hartmann and a shearing inteferometerwave-front sensor " 20 July, 1995 APPLIED OPTICS Vol.34, No.21 4186-4195) defective of this Hartmann wave front sensor is: complex structure, volume are big, firmly degree is relatively poor relatively; When especially under the situation of vibration is arranged, working, be easy to generate relative displacement between microlens array and the ccd detector, the precision susceptible to; Owing to there is coupling mechanism, its installation, debugging be difficulty very.

Summary of the invention

The objective of the invention is to overcome the deficiencies in the prior art and provide a kind of simple in structure, stable, precision is not subject to the integrated form Hartmann wave front sensor of vibration effect.

Purpose of the present invention can realize by following technical measures: Hartmann wave front sensor is made up of microlens array and back lighting type CCD detector, the photosensitive target surface of the focal plane of microlens array and back lighting type CCD detector overlaps, described Hartmann wave front sensor is the integrated chip that is made of back lighting type CCD detector and the microlens array that is made into thereon, one dimension or two-dimentional microlens array that the front of integrated chip is made up of a plurality of sub-lens, its reverse side is the photosensitive target surface of back lighting type CCD detector; Microlens array and sub-lens have different shape, and sub-lens is mapped in the pixel region corresponding on the photosensitive target surface of ccd detector and comprises n * m pixel, wherein, n=1～N is arranged, m=1～M, and must satisfy min (N * M) ≮ (2 * 2).

Purpose of the present invention can realize by following technical measures: the microlens array of Hartmann wave front sensor can be a binary micro fresnel lens array, also can be the continuous surface microlens array, can also be the graded index microlens array.

Purpose of the present invention also can realize by following technical measures: the sub-lens of Hartmann wave front sensor graded index microlens array is a right cylinder, and the refractive index of each sub-lens changes at the mind-set edge from the circle of cylindrical cross section in gradient.

The present invention compared with prior art has following advantage: integrated form Hartmann wave front sensor disclosed in this invention, adopt micro-optic technology or binary optical technique directly microlens array to be produced on the back lighting type CCD detector, constitute the Hartmann wave front sensor integrated chip.Microlens array and back lighting type CCD detector are integrated in one, and the relative position between the two is completely fixed, and is simple in structure, and stability is high, and precision is not vulnerable to vibration effect, can be in operate as normal under the mal-condition; Owing to do not need coupled structure between microlens array and the back lighting type CCD detector, avoided complicated coupling technique simultaneously.This integrated form Hartmann wave front sensor, its microlens array and the sub-lens that is comprised can be made into different shape as required, can adapt to the difformity of incident wavefront; And advantages such as wavefront error is obtained conveniently, speed is fast, the applicable wavelengths scope is big are arranged, can be widely used in ADAPTIVE OPTICS SYSTEMS.

Description of drawings

Fig. 1 is the structural representation of the embodiment of the invention one integrated form Hartmann wave front sensor.

Fig. 2 is the left view of Fig. 1.

Fig. 3 is the right view of Fig. 1.

Fig. 4 is the principle schematic of the integrated form Hartmann wave front sensor of the embodiment of the invention one.

Fig. 5 is the structural representation of the embodiment of the invention two integrated form Hartmann wave front sensors.

Fig. 6 is the left view of Fig. 5.

Fig. 7 is the right view of Fig. 5.

Fig. 8 is the structural representation of the embodiment of the invention three integrated form Hartmann wave front sensors.

Fig. 9 is the right view of Fig. 8.

Figure 10 is the coordinate of the sub-lens axial cross section of embodiment three graded index microlens arrays.

Figure 11 is the refractive index distribution curve of the sub-lens of embodiment three graded index microlens arrays.

Embodiment

The invention will be further described below in conjunction with drawings and Examples.

As shown in Figure 1, the integrated form Hartmann wave front sensor of the embodiment of the invention one comprises binary micro fresnel lens array 1 and back lighting type CCD detector 2.Back lighting type CCD detector 2 is a kind of electrooptical devices, is made on a substrate by integrated circuit technology by photosensitive unit, transparency electrode etc., and the photosensitive target surface 3 of its photosensitive unit is positioned at the back side of substrate.Microlens array 1 is made on the substrate of back lighting type CCD detector 2 by micro-optic technology or binary optical technique, become the Hartmann wave front sensor integrated chip, the photosensitive target surface 3 of microlens array 1 and back lighting type CCD detector 2 lays respectively at two sides of integrated chip, the back side of integrated chip is the photosensitive target surface 3 of ccd detector 2, one dimension or two-dimentional microlens array 1 that its front is made up of a plurality of sub-lens 4.Accurately determine the relative position between microlens array 1 and the ccd detector 2 when designing and producing, guarantee that the focal plane of microlens array 1 and the photosensitive target surface 3 of ccd detector 2 overlap.

As shown in Figure 2, the one-dimensional array formed by two sub-lens 4 of binary micro fresnel lens array 1.Sub-lens 4 is binary micro fresnel lenses of the stepped ramp type of micro-optic technology or binary optical technique making.In the focal plane of lens 4 are focal planes of microlens array 1.As shown in Figure 3, have eight pixels 5 on the photosensitive target surface 3 of back lighting type CCD detector 2, corresponding with the full aperture of incident wavefront.Two sub-lens 4 that binary micro fresnel lens array 1 comprises are divided into two sub-apertures with the incident wavefront full aperture.Each sub-lens 4 is mapped on the photosensitive target surface 3 of ccd detector 2, comprises (2 * 2) individual pixel 5 in its pairing pixel region.

As shown in Figure 4, when inciding the integrated form Hartmann wave front sensor before the random wave, be divided into the plurality of sub wavefront by microlens array 1.Assemble through sub-lens 4 respectively before the divided wavelet, on the photosensitive target surface 3 of back lighting type CCD detector 2, form sub-aperture hot spot; Sub-aperture hot spot is formed spot array.Center (the x of hot spot _i, y _i) calculate by 1. formula:

$x_i=\frac{\underset{m=1}{\overset{M}{\mathrm{\Σ}}}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{x}_{\mathrm{nm}}{I}_{\mathrm{nm}}}{\underset{m=1}{\overset{M}{\mathrm{\Σ}}}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{I}_{\mathrm{nm}}},y_i=\frac{\underset{m=1}{\overset{M}{\mathrm{\Σ}}}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{y}_{\mathrm{nm}}{I}_{\mathrm{nm}}}{\underset{m=1}{\overset{M}{\mathrm{\Σ}}}\underset{n=1}{\overset{N}{\mathrm{\Σ}}}{I}_{\mathrm{nm}}},---\left(1\right)$

In the formula, x _Nm, y _NmBe respectively (n, m) individual pixel 5 is at the coordinate of X, Y direction, and sub-lens 4 is mapped on the photosensitive target surface of ccd detector, comprises n * m pixel 5 in its pairing pixel region, wherein, n=1～N is arranged, m=1～M is (among the embodiment one, n=N=2, m=M=2), I _NmBe (n, m) the spot intensity value of individual pixel 5 outputs.

The position that can calculate all hot spots by 1. formula.Then, obtain wavefront slope g according to 2. formula _Xi, g _Yi:

$g_{\mathrm{xi}}=\frac{x_i-x_0}{\mathrm{\λf}},g_{\mathrm{yi}}=\frac{y_i-y_0}{\mathrm{\λf}}---\left(2\right)$

(in the formula, (x ₀, y ₀) demarcate the spot center reference position that Hartmann sensor obtains for the standard flat ripple; During Hartmann sensor probing wave front-distortion, spot center is displaced to (x _i, y _i)), realize the detecting function of Hartmann wave front sensor to distorted wavefront.

As shown in Figure 5, the integrated form Hartmann wave front sensor of embodiment two is the integrated chip that comprises continuous surface microlens array 6 and back lighting type CCD detector 7.The photosensitive target surface 8 of continuous surface microlens array 6 and back lighting type CCD detector 7 lays respectively at the front and back of integrated chip, and the relative position between the two guarantees by processing.As shown in Figure 6, the two-dimensional array that continuous surface microlens array 6 is made up of seven sub-lens 9 is shaped as circle.Sub-lens 9 is hexagonal continuous surface lenticules, and its focal plane also is the focal plane of continuous surface microlens array 6, overlaps with the photosensitive target surface 8 of ccd detector 7.As shown in Figure 7, have 28 pixels 10 on the photosensitive target surface 8 of back lighting type CCD detector 7.Seven sub-lens 9 are divided into seven sub-apertures with the full aperture of incident wavefront.Each sub-lens 9 is mapped on the photosensitive target surface 8 of ccd detector 7, comprises (2 * 2) individual pixel 10 in its pairing pixel region.

Incident wavefront is cut apart, is focused on the photosensitive target surface 8 of ccd detector 7 through continuous surface microlens array 6, forms spot array.By 1. calculate the position (x of all hot spots with embodiment one described formula _i, y _i).Then, 2. obtain wavefront slope g according to embodiment one described formula _Xi, g _Yi, the detecting function of realization Hartmann wave front sensor.

As shown in Figure 8, the integrated form Hartmann wave front sensor of the embodiment of the invention three, the integrated chip of forming by graded index microlens array 11 and back lighting type CCD detector 12.The front and back of integrated chip is respectively the photosensitive target surface 13 of graded index microlens array 11 and back lighting type CCD detector 12.The photosensitive target surface 13 of the focal plane of graded index microlens array 11 and ccd detector 12 overlaps.Graded index microlens array 11 is made up of the matrix that four sub-lens 14 are arranged in 2 row * 2 row.Sub-lens 14 is divided into four sub-apertures with the full aperture of incident wavefront.As shown in Figure 9, have 16 pixels 15 on the photosensitive target surface 13 of back lighting type CCD detector 12.Each sub-lens 14 is mapped on the photosensitive target surface 13 of ccd detector 12, comprises (2 * 2) individual pixel 15 in its pairing pixel region.

As shown in Figure 8, the sub-lens 14 of graded index microlens array 11 is for mixing the graded index lenticule of other material.Before being split into wavelet during incident wavefront process graded index microlens array 11, the refractive index of wavelet prefactor lens 14 changes in gradient and converges on the photosensitive target surface 13 of back lighting type CCD detector 12.Among the embodiment three, graded index sub-lens 14 is right cylinder (can also be other shapes), right cylinder is that radius is that (Figure 10 represents the coordinate of sub-lens 14 axial cross sections for the circle of r perpendicular to the cross section of optical axis, 17 is the radius r of cross section circle), the refractive index n of each sub-lens 14 mind-set edge from the circle of cross section changes in gradient, its refractive index distribution curve is (ordinate is represented the refractive index n of sub-lens 14 among Figure 11, and horizontal ordinate is represented the radius r of sub-lens 14 cross section circles) as shown in figure 11.

Incident wavefront forms spot array after cutting apart convergence through graded index microlens array 11 on the photosensitive target surface 13 of ccd detector 12.By 1. calculate the position (x of all hot spots with embodiment one described formula _i, y _i).Then, 2. obtain wavefront slope g according to embodiment one described formula _Xi, g _Yi, realize the detecting function of Hartmann wave front sensor to distorted wavefront.

Claims (3)

1, a kind of Hartmann wave front sensor, form by microlens array (1) and back lighting type CCD detector (2), the photosensitive target surface (3) of the focal plane of microlens array (1) and back lighting type CCD detector (2) overlaps, it is characterized in that: described Hartmann wave front sensor is the integrated chip that is made of back lighting type CCD detector (2) and the microlens array (1) that is made into thereon, one dimension or two-dimentional microlens array (1) that the front of integrated chip is made up of a plurality of sub-lens (4), its reverse side is the photosensitive target surface (3) of back lighting type CCD detector (2); Microlens array (1) and sub-lens (4) have different shape, each sub-lens (4) is mapped in the pixel region corresponding on the photosensitive target surface (3) of ccd detector (2) and comprises n * m pixel, wherein, n=1～N is arranged, m=1～M, and must satisfy min (N * M) ≮ (2 * 2).

2, Hartmann wave front sensor according to claim 1, it is characterized in that: described microlens array can be a binary micro fresnel lens array (1), also can be continuous surface microlens array (6), can also be graded index microlens array (11).

3, Hartmann wave front sensor according to claim 1 and 2, it is characterized in that: the sub-lens (14) of described graded index microlens array (11) is a right cylinder, and the refractive index of each sub-lens (14) changes at the mind-set edge from the circle of described cylindrical cross section in gradient.

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