Optoelectronic Sensor Arrangement and Optical Measuring Method

Abstract

In an embodiment an optoelectronic sensor arrangement includes a carrier substrate, an illuminating device, a frequency-selective optical element and a photodetector, wherein the illuminating device and the photodetector form a stacked arrangement on or with the carrier substrate, wherein the frequency-selective optical element is arranged between the illuminating device and the photodetector, wherein the photodetector is arranged in a cavity of the carrier substrate which is covered by the illuminating device and/or the frequency-selective optical element, and wherein the frequency-selective optical element includes a divider mirror and an optical filter.

Claims

1.-19. (canceled)

20. An optoelectronic sensor arrangement comprising: a carrier substrate; an illuminating device; a frequency-selective optical element; and a photodetector, wherein the illuminating device and the photodetector form a stacked arrangement on or with the carrier substrate, wherein the frequency-selective optical element is arranged between the illuminating device and the photodetector, wherein the photodetector is arranged in a cavity of the carrier substrate which is covered by the illuminating device and/or the frequency-selective optical element, and wherein the frequency-selective optical element comprises a divider mirror and an optical filter.

21. The optoelectronic sensor arrangement according to claim 20, wherein the photodetector is located rearwardly of the illuminating device such that electromagnetic radiation received by the photodetector passes through the illuminating device before reaching the photodetector.

22. The optoelectronic sensor arrangement according to claim 20, wherein the frequency-selective optical element is configured to shield the photodetector from electromagnetic radiation emitted by the illuminating device.

23. The optoelectronic sensor arrangement according to claim 20, wherein the divider mirror is a Bragg mirror whose maximum reflectivity is at a wavelength corresponding to a wavelength λ.sub.e of a maximum of a spectral distribution of electromagnetic radiation emitted by the illuminating device.

24. The optoelectronic sensor arrangement according to claim 20, wherein the optical filter is a long-pass filter whose cut-on wavelength λ.sub.c is greater than a wavelength λ.sub.e of a maximum of a spectral distribution of electromagnetic radiation emitted by the illuminating device.

25. The optoelectronic sensor arrangement according to claim 20, wherein the illuminating device is arranged in a direction of its main radiation direction above the photodetector.

26. The optoelectronic sensor arrangement according to claim 20, wherein an overlapping direction of the stacked arrangement is oriented in a direction of a surface normal of the carrier substrate.

27. The optoelectronic sensor arrangement according to claim 20, wherein the photodetector is surrounded by the carrier substrate and/or an electromagnetic radiation-absorbing material such that radiation received by the photodetector passes exclusively through the frequency-selective optical element.

28. The optoelectronic sensor arrangement according to claim 20, wherein the illuminating device is embedded in a reflective material.

29. The optoelectronic sensor arrangement according to claim 20, wherein the illuminating device is an optoelectronic surface emitter or an optoelectronic edge emitter.

30. The optoelectronic sensor arrangement according to claim 29, wherein the illuminating device is a light-emitting diode or a laser-emitting diode.

31. The optoelectronic sensor arrangement according to claim 20, wherein the illuminating device and the photodetector are arranged on the same side of the carrier substrate.

32. The optoelectronic sensor arrangement according to claim 20, wherein the illuminating device and the photodetector are located on different sides of the carrier substrate and an optical window is arranged in the carrier substrate between the illuminating device and the photodetector.

33. The optoelectronic sensor arrangement according to claim 20, wherein the illuminating device and/or the photodetector is a flip-chip mounting element.

34. An optical measuring device comprising: a fiber-optic element optically coupled to the optoelectronic sensor arrangement according to claim 20.

35. An optical measuring method, the method comprising: coupling electromagnetic radiation generated by an illuminating device arranged on a carrier substrate into a fiber-optic element; and returning at least a portion of the radiation backscattered in the fiber-optic element to a photodetector which forms a stacked arrangement with the illuminating device on or with the carrier substrate, wherein the photodetector is located rearwardly of the illuminating device such that the electromagnetic radiation received by the photodetector passes through the illuminating device and through a frequency-selective optical element arranged between the illuminating device and the photodetector before reaching the photodetector.

36. The method according to claim 35, wherein the frequency-selective optical element exclusively transmits electromagnetic radiation which is frequency-shifted with respect to the electromagnetic radiation emitted by the illuminating device.

37. The method according to claim 35, wherein a wavelength of the backscattered radiation depends on an elongation state of the fiber-optic element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In the following, exemplary embodiments of the invention are explained in connection with figure representations. These show, in each case schematically, the following:

[0016] FIG. 1 shows a cross-sectional view of an optoelectronic sensor arrangement according to embodiments;

[0017] FIG. 2 illustrates the optical measuring method according to embodiments;

[0018] FIG. 3 shows an optical measuring device according to Embodiments,

[0019] FIG. 4 a cross-sectional view of a second embodiment of the optoelectronic sensor arrangement; and

[0020] FIG. 5 a cross-sectional view of a third embodiment of the optoelectronic sensor arrangement.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0021] FIG. 1 represents a first embodiment of the optoelectronic sensor arrangement 1 in a schematically simplified cross-sectional view. Shown is a stacked arrangement 5 of an illuminating means 3 in the form of a light emitting diode, a frequency-selective optical element 6 and a photodiode 4 on a carrier substrate 2. The overlapping direction 10 of the stacked arrangement 5 corresponds to the direction of the surface normal of the carrier substrate 2. Here, seen in the main radiation direction 9, the illuminating means 3 lies above the frequency-selective optical element 6, which in turn is arranged above the photodiode 4.

[0022] The stacked arrangement 5 is laterally enclosed by a reflective material 11 in concave mirror form and an optical barrier 19 in such a way that electromagnetic radiation from the upper side 13 of the illuminating means 3 can take place in the main radiation direction 10. The frequency-selective optical element 6 arranged on the back side of the illuminating means 3 comprises a divider mirror 7 in the form of a Bragg mirror whose maximum reflectivity is for a wavelength corresponding to the wavelength λ.sub.e of the maximum of the spectral distribution of the electromagnetic radiation emitted by the illuminating means 3. The further part of the frequency-selective optical element 6 is formed by an optical filter 8 arranged under the divider mirror 7, which is designed as a long-pass filter whose cut-on wavelength λ.sub.c is greater than the wavelength λ.sub.e of the maximum of the spectral distribution of the electromagnetic radiation emitted by the illuminating means 3.

[0023] The photodetector 4 is enclosed by a layer of electromagnetic radiation-absorbing material 11 and the opaque carrier substrate 2 in such a way that the radiation to be detected reaches the photodetector 4 exclusively through the frequency-selective optical element 6 of the stacked arrangement 5. In this way, the measuring method illustrated in FIG. 2 can be realized.

[0024] The illumination of a measuring object 20 by the illuminating means 3 is shown with a spectral distribution whose maximum lies at a wavelength of λ.sub.e. At least a portion of the light backscattered by the measuring object 20 comprises a wavelength of λ.sub.f which is frequency shifted with respect to the wavelength λ.sub.e, wherein λ.sub.f>λ.sub.e is assumed. By choosing the cut-on wavelength λ.sub.c of the optical filter 8 to be λ.sub.f>λ.sub.c>λ.sub.e, only the light backscattered from the measuring object 20 reaches the photodetector 4. If the optical measuring device shown schematically simplified in FIG. 3 is used for the measurement with a fiber-optic element 16 to which an optoelectronic sensor arrangement 1 is optically coupled, the frequency shift of the backscattered radiation with wavelength λ.sub.f depends on the strain state of the fiber-optic element 16, which can be determined by the signal at the photodetector 4.

[0025] FIG. 4 shows a schematically simplified cross-sectional view of a second embodiment of the optoelectronic sensor arrangement 1. The same reference signs are used for the components corresponding to the first embodiment. The arrangement of the photodetector 4 in a cavity of the carrier substrate 2 is shown, which is covered by the divider mirror 7 of the frequency-selective element 6 and the illuminating means 3 in such a way that all the radiation incident on the photodetector 4 must pass through the illuminating means 3 and the frequency-selective optical element 6.

[0026] The contacting 17.2 of the illuminating means 3 is from the back side, so that a flip-chip mounting element can be used. Accordingly, the photodetector 4 can be formed by a flip-chip mounting element if, as shown in FIG. 4, the contacting 17.3 from the carrier substrate back side is realized by a via connection in the bottom of the cavity.

[0027] FIG. 5 shows a schematically simplified cross-sectional view of a third embodiment of the optoelectronic sensor arrangement 1. This has an arrangement of the illuminating means 3 on a first side of the carrier substrate 2, while the photodetector 4 is placed on the opposite substrate side. Accordingly, the carrier substrate 2 is additionally part of the stacked arrangement 5, which comprises the illuminating means 3, the frequency-selective optical element 6 and the photodetector 4. In this case, the photodetector 4 is surrounded by an opaque component made of an electromagnetic radiation-absorbing material 14 and radiation can only enter the measuring area through an optical window 15 in the carrier substrate 2, which is covered by the illuminating means 3 and the frequency-selective optical element 6. For the shown embodiment, the illuminating means 3 and the photodetector 4 can advantageously be realized by flip-chip mounting elements, the contacts 17.4 and 17.5 of which originate from the respective assigned side of the carrier substrate 2.

[0028] Although the invention has been illustrated and described in detail by means of the preferred embodiment examples, the present invention is not restricted by the disclosed examples and other variations may be derived by the skilled person without exceeding the scope of protection of the invention.