DEVICE FOR DETECTING A GEOMETRY OF A DROP ARRANGED ON A SAMPLE SURFACE

Abstract

A device for detecting a geometry of a drop arranged on a sample surface includes a metering apparatus comprising a liquid reservoir and an outlet opening and a plurality of light sources configured to direct light onto a surface of the drop of liquid. A camera is configured to detect a reflection of the light from the surface of the drop of liquid. The device includes a housing including a recess that forms a cavity that is configured to be separated from external surroundings when the housing is arranged on the sample surface. The plurality of light sources are arranged in the cavity and cover a solid angle of at least π/2 sr when viewed from a point on the sample surface. At least a portion of the metering apparatus is positioned inside the cavity.

Claims

1. A device for detecting a geometry of a drop arranged on a sample surface, comprising: a metering apparatus comprising a liquid reservoir and an outlet opening, wherein the metering apparatus is configured to apply a drop of liquid on the sample surface; a plurality of light sources configured to direct light onto a surface of the drop of liquid; and a camera configured to detect a reflection of the light from the surface of the drop of liquid; and a housing including a recess that forms a cavity, wherein the cavity is configured to be separated from external surroundings when the housing is arranged on the sample surface, wherein the plurality of light sources are arranged in the cavity, wherein the plurality of light sources cover a solid angle of at least π/2 sr when viewed from a point on the sample surface, and wherein at least a portion of the metering apparatus is positioned inside the cavity.

2. The device according to claim 1, wherein the plurality of light sources comprise multiple first light sources and multiple second light sources, wherein the multiple first light sources are smaller than the multiple second light sources.

3. The device according to claim 1, wherein the plurality of light sources comprise multiple first light sources and multiple second light sources, wherein the multiple first light sources are arranged at shorter distances from one another than are the multiple second light sources.

4. The device according to claim 3, wherein the multiple first light sources are arranged such that they are imaged on a sensor of the camera by means of a reflection from the sample surface on which the housing is arranged.

5. The device according to claim 3, wherein the multiple second light sources are arranged such that they are not imaged on a sensor of the camera by means of a reflection from the sample surface on which the housing is arranged.

6. The device according to claim 1, wherein at least some of the plurality of light sources are arranged on a lateral surface of a cylinder or cone.

7. The device according to claim 1, wherein at least some of the plurality of light sources are arranged on a flexible circuit board that is coupled to the housing.

8. The device according to claim 7, further comprising control electronics configured to control the plurality of light sources positioned on the flexible circuit board.

9. The device according to claim 1, wherein at least some of the plurality of light sources are image points of an OLED screen.

10. The device according to claim 1, wherein at least some of the plurality of light sources emit infrared light.

11. The device according to claim 1, wherein the metering apparatus is configured to apply the liquid onto the sample surface as one of a continuous jet or a succession of droplets.

12. The device according to claim 1, wherein the metering apparatus is configured to transport the liquid onto the sample surface in a direction that extends substantially perpendicularly to the sample surface.

13. The device according to claim 1, wherein the outlet opening is formed at one end of a metering tube that protrudes into the cavity.

14. The device according to claim 1, wherein the metering apparatus comprises a movable portion on which the outlet opening is arranged, and wherein the movable portion is configured to be at least partially moved out of the cavity.

15. The device according to claim 1, wherein the housing comprises an adapter fastened to the housing and a receiving portion for a sample, wherein the receiving portion includes a defined geometry.

16. The device according to claim 1, further comprising an additional camera configured to detect a reflection of the light sources from the surface of the drop, wherein the camera and the additional camera comprise different viewing directions.

17. The device according to claim 16, further comprising a distance measuring apparatus configured to determine a distance between the device and the sample surface, wherein the distance measuring apparatus comprises a laser configured to direct a laser light onto the sample surface, and wherein the laser light is detected by at least one of the camera and the additional camera.

18. The device according to claim 1, wherein the camera comprises a sensor including a sensor plane, a lens including a lens plane and an object plane extending along the sample surface, wherein the sensor plane, the lens plane, and the object plane intersect in a common straight line.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The invention is explained in greater detail below with reference to exemplary embodiments represented in figures, in which:

[0034] FIG. 1 schematically illustrates a cross-sectional representation of an embodiment of a device for detecting a geometry of a drop arranged on a sample surface; and

[0035] FIG. 2 is a photograph of another embodiment of the device for detecting a geometry of a drop arranged on a sample surface.

DETAILED DESCRIPTION OF THE INVENTION

[0036] FIG. 1 shows a sample 10 having a flat sample surface 12 on which a device 14 is arranged. The device 14 serves to detect a geometry of a drop 16 arranged on the sample surface 12. The device 14 comprises a housing 18, on the underside 20 of which feet 22 are arranged, which feet each form a contact point and which are in contact with the sample surface 12 in the arrangement shown. The housing 18 is therefore in a defined position relative to the sample surface 12. The housing 18 comprises a recess 24, which is not shown in more detail in FIG. 1. When the housing 18 is arranged on the sample surface 12, said recess 24 forms a cavity 26 which is separated from the surroundings.

[0037] Moreover, the device 14 comprises a metering apparatus 28. The metering apparatus 28 comprises a liquid reservoir 30 and an outlet opening 32, which is arranged at a lower end of a metering tube 34 and protrudes into the cavity 26. By means of the metering apparatus 28, liquid can be applied onto the sample surface 12 in the form of a continuous jet from the liquid reservoir 30. The jet direction 36 is oriented approximately perpendicularly to the sample surface 12.

[0038] Moreover, the device 14 comprises a camera 38, which has a lens 40 and a sensor 42. A viewing direction 44 of the camera 38 is indicated by a dashed line and directed onto the drop 16. In the arrangement shown, the sensor 42 is located in a sensor plane 48, the lens 40 is located in a lens plane 46, and the sample surface 12 is located in an object plane 50. As schematically shown, the three planes 46, 48, 50 intersect in a common straight line 52 or point.

[0039] A plurality of light sources is arranged inside the cavity 26, including multiple first light sources 54 and multiple second light sources 56, 58, 60. The first light sources 54 are smaller than the second light sources 56, 58, 60 and are also arranged at shorter distances from one another than the second light sources 56, 58, 60.

[0040] The first light sources 54 and the second light sources 56 are arranged on a flexible circuit board 62, which is glued in a planar manner to a support part (not shown) of the housing 18. The flexible circuit board 62 extends along a lateral surface of an elliptical cylinder, which is not visible in the cross-section of FIG. 1.

[0041] The second light sources 58 are arranged on a first rigid circuit board 64 and the second light sources 60 are arranged on a second rigid circuit board 66. The second rigid circuit board 66 comprises a through-opening 68, behind which the camera 38 is arranged. An additional opening 70 is located between the flexible circuit board 62 and the second rigid circuit board 66. The metering tube 34 protrudes through said opening 70 and into the cavity 26.

[0042] The flexible circuit board 62 also comprises a through-opening 76, behind which a cross laser 78 is arranged. The cross laser 78 is arranged such that it projects a cross onto the sample surface 12 in the region of the drop 16, as indicated by the lines 80.

[0043] The recess 24 in the housing 18 is substantially lined by the first rigid circuit board 64, the second rigid circuit board 66, and the flexible circuit board 62. The cavity 26 above the sample surface 12 is approximately dome-shaped, wherein the first rigid circuit board 64 is oriented approximately perpendicularly to the sample surface 12 and the second rigid circuit board 66 forms a ceiling portion arranged obliquely with respect to the sample surface 12. The remaining wall surface of the recess 24 is covered by the flexible circuit board 62, which is more clearly visible in FIG. 2.

[0044] FIG. 2 shows an embodiment of a device that is configured to substantially correspond to the device 14 from FIG. 1. In particular, in this case, there is also a flexible circuit board 62, which is arranged on a developable surface, namely an elliptical cylinder lateral surface. A housing 18 having an underside 20 is also clearly visible. In the example of FIG. 2, the recess 24 formed in the housing 18 is also substantially lined by a first rigid circuit board 64, a second rigid circuit board 66, and the flexible circuit board 62. These three circuit boards 64, 66, 62 are arranged as described with reference to FIG. 1.

[0045] It can be seen in FIG. 2 that the second rigid circuit board 66 comprises two through-openings 68, 82. The camera 38 (not visible) is located behind the through-opening 68 and an additional camera (not visible either) is located behind the through-opening 82. The metering apparatus 28 having the metering tube 34 is also clearly visible.

[0046] Moreover, FIG. 2 shows an additional circuit board 84, which is arranged on the side of the first rigid circuit board 64 that is facing away from the cavity 26 and which contains control electronics (72). The first light sources 54 are arranged in two groups in a matrix-like manner. The first group 86, which is bordered by a dashed line, is arranged such that, when the housing 18 is arranged on a reflective, flat sample surface 12, the light emitted by the associated first light sources 54 is detected by the camera 38 behind the through-opening 68 after being reflected on the reflective surface. The same applies to the first light sources 54 of the second group 88, the light from which is reflected into the additional camera located behind the other through-opening 82.

[0047] Each of the groups 86, 88 of first light sources 54 extends over a solid angle range of approximately π/12 sr. The entirety of the first and second light sources 54, 56, 58, 60 extends over a solid angle range of approximately 3/2 π sr. In both cases, as explained, the solid angle range is viewed from a point on a flat sample surface 12, in particular from the point at which the drop 16 is applied.

LIST OF REFERENCE SIGNS

[0048] 10 Sample

[0049] 12 Sample surface

[0050] 14 Device

[0051] 16 Drop

[0052] 18 Housing

[0053] 20 Underside

[0054] 22 Foot

[0055] 24 Recess

[0056] 26 Cavity

[0057] 28 Metering apparatus

[0058] 30 Liquid reservoir

[0059] 32 Outlet opening

[0060] 34 Metering tube

[0061] 36 Jet direction

[0062] 38 Camera

[0063] 40 Lens

[0064] 42 Sensor

[0065] 44 Viewing direction

[0066] 46 Lens plane

[0067] 48 Sensor plane

[0068] 50 Object plane

[0069] 52 Common straight line

[0070] 54 First light source

[0071] 56 Second light source

[0072] 58 Second light source

[0073] 60 Second light source

[0074] 62 Flexible circuit board

[0075] 64 First rigid circuit board

[0076] 66 Second rigid circuit board

[0077] 68 Through-opening

[0078] 70 Opening

[0079] 72 Control electronics

[0080] 76 Through-opening

[0081] 78 Laser

[0082] 80 Lines

[0083] 82 Through-opening

[0084] 84 Additional circuit board

[0085] 86 First group of first light sources

[0086] 88 Second group of first light sources