Apparatus and method for capturing an image

Abstract

Apparatus and method for capturing an image having a detection beam path for guiding detection radiation from a sample to a detector having a plurality of detector elements. The detector has no more than ten and, preferably, four or five detector elements; and an evaluation unit, which is configured to carry out an evaluation in accordance with the Airyscan method on the image data captured by means of the detector and which generates a high-resolution image.

Claims

1. Image capturing apparatus comprising a detection beam path for guiding detection radiation from a sample to a detector having a plurality of detector elements, wherein the detector has four or five detector elements; and further comprising an evaluation unit configured to carry out an evaluation in accordance with an Airyscan method on image data captured by means of the detector and which generates a high-resolution image.

2. Apparatus according to claim 1, wherein the detector is arranged in a detector plane that is conjugate to a focal plane.

3. Apparatus according to claim 1, wherein a pinhole with a fixed or variable diameter is arranged in the beam path in a plane that is conjugate to the focal plane.

4. Apparatus according to claim 1, wherein a phase element is arranged in the detection beam path, and incident detection radiation is split into at least two partial beams by effect of the phase element and each of the partial beams is steered to a different detector element of the detector in each case and captured as measurement values.

5. Image capturing method, comprising capturing detection radiation coming from a sample in a detection beam path by means of a detector which has a plurality of detector elements, comprising using a detector which has four or five detector elements and which captures image data and there is confocal parallel sampling of a point spread function; and evaluating the image data captured by means of the detector by means of an evaluation unit and a high-resolution image is generated.

6. Method according to claim 5, further comprising splitting said detection radiation into at least two partial beams and steering each of the partial beams to a different detector element of a detector in each case and captured as image values.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention is described in more detail below on the basis of exemplary embodiments and figures. In detail:

(2) FIG. 1 shows a schematic illustration of a first exemplary embodiment of an apparatus according to the invention;

(3) FIG. 2a shows a schematic illustration of the cathode arrangement of a quadrant PMT detector;

(4) FIG. 2b shows a schematic illustration of the cathode arrangement of a 5-channel detector;

(5) FIG. 3 shows a schematic illustration of a first exemplary embodiment of a phase element with four quadrants;

(6) FIG. 4 shows a schematic illustration of a second exemplary embodiment of an apparatus according to the invention;

(7) FIG. 5 shows a schematic illustration of a second exemplary embodiment of a phase element in the form of a refractive phase mask.

DESCRIPTION OF THE INVENTION

(8) The invention will be explained on the basis of exemplary embodiments, with the same reference signs denoting the same technical units or elements provided nothing else is expressly stated.

(9) A first exemplary embodiment of an apparatus according to the invention is illustrated in FIG. 1 in exemplary fashion and not true to scale. A beam of detection radiation, in particular light in the visible and/or infrared wavelength range, propagates along a beam path 2, in particular a detection beam path 2, of a microscope as apparatus 1 (not illustrated in any more detail) and strikes a pinhole 14. As a result of the effect of the latter, out-of-focus components of the detection radiation are partially removed from the beam path 2 and the beam diameter is restricted. The pinhole 14 can be embodied with a fixed or with a variably adjustable diameter of the passage opening. In addition to partly blocking unwanted radiation components, the pinhole 14 can be used to adapt the beam diameter to the dimensions of the detector 7.

(10) By means of downstream optics 6, which can be substantially more complex than shown in FIG. 1, the detection radiation that has passed through the pinhole 14 is steered to different detector elements 7.1 to 7.4 of a detector 7, which is embodied as a quadrant detector, in the detector plane 8. The image data captured by means of the detector 7 are evaluated by means of an evaluation unit 10 and optionally stored. The evaluation unit 10 is configured to carry out the Airyscan method by virtue of the point spread function (PSF) of the apparatus 1 being sampled in parallel on the basis of the captured image data.

(11) In particular, a quadrant PMT detector (FIG. 2a) with the detector elements 7.1 to 7.4 or a detector with five detector elements 7.1 to 7.5 (FIG. 2b) can be used as detectors 7.

(12) A phase element 4 can be disposed upstream of the detector (FIGS. 3, 4) in order to reduce or even avoid unwanted light losses at the webs 7S (only some of which have been labeled in exemplary fashion) which separate the detector elements 7.1 to 7.n from one another.

(13) The phase element 4 can be subdivided into a plurality of partial areas 4.1 to 4.4 (FIG. 3). The phase element 4, for example a phase mask, can be subdivided into four quadrants of equal size, which each deflect the light away from the center of the phase element 4, as symbolized in FIG. 3 by arrows. The arrows schematically represent partial beams 5.1 to 5.4 caused by the effect of the phase element 4. In the case of the simplest design of the phase element 4, the quadrants are faces that are tilted with respect to one another or prisms with surfaces that are tilted with respect to one another, which thus generate lateral beam offsets or beam deflections.

(14) While the split of the radiation into the partial beams 5.1 to 5.4 is brought about by a uniform deflection of components of the radiation by means of the phase element 4, a phase element 4 in which refraction/diffraction (depending on setup) in the central region of the phase element 4 is avoided can be used if use is made of a detector 7 with five detector elements 7.1 to 7.5 (see FIG. 2b).

(15) In a second exemplary embodiment of the apparatus according to the invention, a beam, in particular a light beam of detection radiation, propagates along a beam path 2 and strikes a phase element 4 which is embodied as a phase mask in this case (FIG. 4). In further embodiments, the phase element can be embodied in the form of a grating, for example. As a result of the effect of the phase element 4, the radiation is split into, for example, four partial beams 5.1 to 5.4, of which only the partial beams 5.1 and 5.2 are shown in the beam path so as to have a better overview.

(16) The partial beams 5.1 to 5.4 are steered by means of optional downstream optics 6 to different detector elements 7.1 to 7.4 of the detector 7 in the detector plane 8 and are imaged there in four spots 9 (see image insert). By way of example, a quadrant PMT detector, a quadrant photodiode, a quadrant APD/SPAD detector, arrays of MPPC/SiPM elements or a 5-channel detector can be used as detector 7, which captures the measurement values of the respective partial beams 5.1 to 5.4 (partial beams 5.1 to 5.5 in the case of a 5-channel detector) and transmits these to the evaluation unit 10. Measurement values of a set or dynamically selected number of detector elements 7.1 to 7.4 (detector elements 7.1 to 7.5 in the case of a 5-channel detector) can be combined in this case by calculation in the evaluation unit 10 (“binning”).

(17) A control unit 11, which is connected to the evaluation unit 10, can optionally be present. If necessary, required corrections to the position of the phase element 4 in the beam path 2 can be identified and the control commands required to carry out the corrections can be generated. The control commands are used to control a drive unit 12 and the alignment and relative position of a component 13 (indicated in the illustration) holding the phase element 4 is altered relative to the beam path 2.

(18) To generate a phase element 4, for example a quadrant phase mask, plane-parallel plates, for example, can be tilted and the refractive effect of the plates caused thereby can be used. Alternatively, use can be made of a refractive design, in respect of which a schematic example is indicated in FIG. 5. The continuous profile brings about imaging of four spots 9 in the detector plane 8, as already described in relation to FIG. 4.

(19) A diffractive design of the phase element 4 can be chosen in further embodiments. Diffractive designs are usually producible in a simpler and more cost-effective manner than refractive designs.

(20) While the invention has been illustrated and described in connection with currently preferred embodiments shown and described in detail, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. The embodiments were chosen and described in order to best explain the principles of the invention and practical application to thereby enable a person skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.

REFERENCE SIGNS

(21) 1 Apparatus 2 Beam path, detection beam path 3 Optical axis 4 Phase element 4.1 to 4.n Partial areas (of the phase element 4) 5.1 to 5.n Partial beam 6 Optics 7 Detector 7.1 to 7.n Detector element 7S Web 8 Detector plane 9 Spot 10 Evaluation unit 11 Control unit 12 Drive unit 13 Component 14 Pinhole