OPTOELECTRONIC DEVICE AND METHOD

Abstract

An optoelectronic device may include an arrangement having a plurality of emitter elements configured to sequentially emit light of different wavelength ranges. The arrangement may include a plurality of time-of-flight detector elements configured to detect the light emitted by the emitter elements and reflected at a sample and to carry out a measurement for determining the distance of the reflection point of the light at the sample from the respective time-of-flight detector element. The device further includes an evaluation unit configured to generate a three-dimensional image of the sample for each wavelength range emitted by the emitter elements on the basis of the light detected by the time-of-flight detector elements and the distance of the reflection point of the light from the respective time-of-flight detector element and to determine the distribution of a substance in the sample from the images.

Claims

1. An optoelectronic device comprising: an arrangement comprising a plurality of emitter elements configured to sequentially emit light of different wavelength ranges; an arrangement comprising a plurality of detector elements configured to detect the light emitted by the emitter elements and reflected from a sample; wherein the arrangement of the plurality of emitter elements and the arrangement of the plurality of detector elements are arranged in a common housing, wherein the arrangement of the plurality of emitter elements is arranged in a first cavity in the housing and the arrangement of the plurality of detector elements is arranged in a second cavity in the housing, and wherein the first cavity and the second cavity are optically separated from each other by a partition wall; and an evaluation unit configured to generate a two-dimensional single image of the sample for each wavelength range emitted by the emitter elements based on the light detected by the detector elements and to determine an overall image of the sample from the single images, the overall image comprising a plurality of image points, each of which comprises a superposition of the light reflected from the sample and detected by the detector elements.

2. The optoelectronic device according to claim 1, wherein a detector element is associated with each image point and the overall image in that image point contains a superposition of all wavelength ranges detected by that detector element.

3. (canceled)

4. (canceled)

5. The optoelectronic device according to claim 4, wherein the partition wall comprises the same material as the housing.

6. The optoelectronic device according to claim 1, wherein the optoelectronic device is configured as a leadframe package, ceramic package, or chip-size package.

7. The optoelectronic device according to claim 1, wherein an optical lens is arranged in front of the detector elements and/or in front of the plurality of emitter elements.

8. The optoelectronic device according to claim 1, wherein the plurality of emitter elements are configured to emit light in the infrared spectral region.

9. The optoelectronic device according to claim 1, wherein the plurality of emitter elements are configured to emit broadband light, and wherein a wavelength filter is arranged above each of the emitter elements.

10. The optoelectronic device according to claim 1, wherein at least two emitter elements of the plurality of emitter elements are configured to emit light having the same wavelength.

11. The optoelectronic device according to claim 10, wherein a converter element is arranged above at least one of the at least two emitter elements; wherein the converter element is configured to convert the light emitted by the emitter element.

12. The optoelectronic device according to claim 1, wherein electrical connections for the arrangement of the plurality of emitter elements and the arrangement of the plurality of detector elements are formed on a bottom side of the optoelectronic device.

13. The optoelectronic device according to claim 1, further comprising a control unit for controlling the emitter elements and the detector elements.

14. The optoelectronic device according to claim 13, wherein the evaluation unit and the control unit are integrated in a common housing.

15. An optoelectronic device comprising: an arrangement comprising a plurality of emitter elements configured to sequentially emit light of different wavelength ranges; an arrangement comprising a plurality of time-of-flight detector elements configured to detect the light emitted by the emitter elements and reflected from a sample and to determine the distance of the reflection point of the light from the sample from the respective time-of-flight detector element; and an evaluation unit configured to generate a three-dimensional image of the sample for each wavelength range emitted by the emitter elements based on the light detected by the time-of-flight detector elements and the distance of the reflection point of the light from the respective time-of-flight detector element, and to determine the distribution of a substance in the sample from the images.

16. The optoelectronic device according to claim 15, wherein at least a portion of the absorption spectrum of the substance is stored in a memory unit, and wherein the evaluation unit is configured to determine the distribution of the substance in the sample from the images using the at least a portion of the absorption spectrum.

17. The optoelectronic device according to claim 15, wherein the arrangement comprising the plurality of emitter elements is arranged in a first cavity and the arrangement comprising the plurality of time-of-flight detector elements is arranged in a second cavity.

18. The optoelectronic device according to claim 15, further comprising a control unit for controlling the emitter elements and the time-of-flight detector elements.

19. The optoelectronic device according to claim 18, wherein the evaluation unit and the control unit are integrated into a common component.

20. The optoelectronic device according to claim 15, wherein the light sequentially emitted by the emitter elements of different wavelength ranges comprises light from the near-infrared spectral range.

21. The optoelectronic device according to claim 15, wherein at least one optical lens is arranged in front of the time-of-flight detector elements.

22. A method for determining the distribution of a substance in a sample, wherein the method comprises: sequentially emitting light of different wavelength ranges via an arrangement comprising a plurality of emitter elements, wherein the light emitted by the emitter elements is reflected from a sample; detecting the light reflected from the sample via an arrangement comprising a plurality of time-of-flight detector elements; determining the distance of the reflection point of the light from the sample from each respective time-of-flight detector element; generating a three-dimensional image of the sample, for each wavelength range emitted by the emitter elements, based on the light detected by the time-of-flight detector elements and the distance of the reflection point of the light from the respective time-of-flight detector element; and determining the distribution of a substance in the sample from the images.

23. (canceled)

24. (canceled)

25. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In the following, non-limiting embodiments are explained in more detail with reference to the accompanying drawings. In these schematically show:

[0049] FIG. 1A an illustration of an embodiment of an optoelectronic device in a top view;

[0050] FIG. 1B a side view of the optoelectronic device of FIG. 1A;

[0051] FIG. 2A an equivalent circuit diagram of a time-of-flight detector pixel;

[0052] FIG. 2B an illustration of the operation of the time-of-flight detector pixel of FIG. 2A;

[0053] FIG. 3 illustrations of three-dimensional reflectance images of an apple and a representation of the distribution of a substance in the apple;

[0054] FIGS. 4A to 4C illustrations of further embodiments of an optoelectronic device in a top view; and

[0055] FIG. 5 an illustration of an optoelectronic device in a side view.

[0056] In the following detailed description, reference is made to the accompanying drawings, which form a part of this description and in which non-limiting embodiments may be practiced are shown for illustrative purposes. Since components of embodiments may be positioned in a number of different orientations, the directional terminology is for illustrative purposes and is not limiting in any way. It is understood that other embodiments may be used and structural or logical changes may be made without departing from the scope of protection. It is understood that the features of the various embodiments described herein may be combined with each other, unless specifically indicated otherwise. Therefore, the following detailed description is not to be construed in a limiting sense. In the figures, identical or similar elements are provided with identical reference signs where appropriate.

DETAILED DESCRIPTION

[0057] FIGS. 1A and 1B schematically show an optoelectronic device 10 in a top view and a side view, respectively. The structure and operation of the optoelectronic device 10 are described below.

[0058] The optoelectronic device 10 includes an arrangement 11 comprising a plurality of emitter elements 12 and an arrangement 13 comprising a plurality of time-of-flight detector elements 14. Furthermore, an evaluation unit and a control unit are integrated in an integrated circuit 15.

[0059] The arrangement 11 with the emitter elements 12 is mounted on the integrated circuit 15, which is arranged together with the arrangement 11 in a first cavity. The arrangement 13 with the time-of-flight detector elements 14 is arranged in a second cavity. In the present embodiment, the time-of-flight detector elements 14 are the pixels of a CMOS time-of-flight camera chip. A camera lens 16 is arranged above the arrangement 13 as a lens.

[0060] During operation of the optoelectronic device 10, the emitter elements 12 sequentially emit light of different wavelengths or wavelength ranges. In the arrangement 11, each of the emitter elements 12 emits light at a wavelength or in a wavelength range that is different from the wavelength or wavelength range of the light emitted by the remaining emitter elements 12.

[0061] The light emitted by the emitter elements 12 is at least partially incident on a sample 17, the contents of which are to be examined by means of the optoelectronic device 10. A portion of the light is reflected from the sample to the camera lens 16. The light passes through the camera lens 16 and falls on the time-of-flight detector elements 14. The outlined path of the light is illustrated by arrows 18 and 19 in FIG. 1B.

[0062] Each of the time-of-flight detector elements 14 measures the intensity of light incident on the respective time-of-flight detector element 14. Furthermore, each of the time-of-flight detector elements 14 performs a measurement which allows to determine the distance between the reflection point of the light at the sample 17 and the respective time-of-flight detector element 14.

[0063] The time-of-flight detector elements 14 may be, for example, CMOS detector pixels 20 that operate according to so-called quadrature modulation. The equivalent circuit of a detector pixel 20 is shown in FIG. 2A.

[0064] The detector pixel 20 includes a photodiode 21 and two capacitors 22 and 23, each of which can be connected between a supply voltage VDD and a ground VSS by means of switches 24 to 26. Switch 24 is connected between the supply voltage VDD and a common node 27. Switches 25 and 26 are connected between the common node 27 and capacitors 22 and 23, respectively.

[0065] The operation of the detector pixel 20 is shown schematically in FIG. 2B. The control unit included in the integrated circuit 15 controls the emitter elements 12 such that an emitter element 12 periodically emits light at a predetermined wavelength or range of wavelengths, as shown in the first line of FIG. 2B. The capacitor 22 is connected to the photodiode 21 during the time that the emitter element 22 emits light, and is disconnected from the photodiode 22 during the rest of the time. In the case of the capacitor 23, the reverse is true, i.e., the capacitor 23 is connected to the photodiode 21 between two successive pulses emitted by the emitter element 12 and is disconnected from the photodiode 21 during the light emission by the emitter element 12. To accomplish this, the control unit controls switches 25 and 26 such that switch 25 is closed during a light pulse and otherwise open, and switch 26 is closed between successive light pulses and otherwise open. Switch 24 is controlled by the control unit such that it is closed during the complete measurement process.

[0066] Based on the above, capacitor 22 is charged by photodiode 21 during the emission of one light pulse, while capacitor 23 is charged by photodiode 21 between the emission of two successive light pulses.

[0067] Since the light emitted from the emitter element 12 is first reflected from the sample 17, it reaches the photodiode 21 with a certain time delay, as shown in the second row of FIG. 2B. This time delay causes capacitor 22 to be periodically charged with an amount of charge Q.sub.1, while capacitor 23 is periodically charged with an amount of charge Q.sub.2. The charges Q.sub.1 and Q.sub.2 are integrated over a predetermined time period 28. Using the ratio of the charges accumulated in the capacitors 22 and 23 during the time period 28, the evaluation unit included in the integrated circuit 15 can determine the time offset of the reflected light pulse and, from this, the distance of the respective detector pixel 20 from the reflection point on the sample 17. In particular, the distance of the emitter elements 12 from the sample 17 is known.

[0068] Consequently, for each wavelength or wavelength range emitted by the emitter elements 12, the evaluation unit has available both the light intensity of the reflected light detected by the time-of-flight detector elements 14 and the distance of the respective time-of-flight detector element 14 from the reflection point on the sample 17. From these data, the evaluation unit generates a spatially three-dimensional image of the sample 17 for each wavelength or range of wavelengths emitted by the emitter elements 12.

[0069] As an example, FIG. 3 shows four three-dimensional reflection images of an apple as sample 17. The four reflection images were taken with light of wavelengths 750 nm, 800 nm, 850 nm and 900 nm. In the present example, the distribution of a substance in the apple is to be investigated, which has an absorption maximum at approximately 850 nm. Consequently, light with this wavelength is strongly absorbed and therefore only slightly reflected, whereas light with other wavelengths is more strongly reflected.

[0070] The absorption spectrum of the substance to be examined or at least a portion of the absorption spectrum is stored in a memory unit to which the evaluation unit has access. With the help of the absorption spectrum and the four three-dimensional reflection images of the apple, the evaluation unit can generate a three-dimensional representation shown in FIG. 3 on the right, which shows the distribution of the substance in the apple. In the representation of FIG. 3, the area with the highest concentration of the substance under investigation is indicated.

[0071] FIGS. 4A to 4C schematically show three embodiments of an optoelectronic device 100 in a top view. FIG. 5 schematically shows an optoelectronic device 100 in a side view. The structure and operation of the optoelectronic device 100 are described below.

[0072] The optoelectronic device 100 includes an arrangement 110 configured as an array comprising a plurality of emitter elements 120, and an arrangement 130 comprising a plurality of detector elements. In this regard, the arrangement of the plurality of detector elements is shown only as a block comprising multiple detector elements (not shown). The detector elements may be formed, for example, by the pixels of a CMOS camera chip.

[0073] The arrangement 110 with the emitter elements 120 is arranged in a first cavity 162. The arrangement 130 with the detector elements is arranged in a second cavity 163. The two cavities are separated from each other by a partition wall 166, in particular optically separated from each other. The two cavities and the partition wall 166 are formed by a housing 164, in which the arrangement 110 with the emitter elements 120 and the arrangement 130 with the detector elements are arranged. Furthermore, an evaluation unit not shown here and a control unit may also be arranged in the housing 164.

[0074] During operation of the optoelectronic device 100, the emitter elements 120 sequentially emit light of different wavelengths or wavelength ranges at least partially onto a sample. For example, an optical lens 160 in front of the plurality of emitter elements may be configured to project the light emitted by the emitter elements onto the sample to be examined. The optoelectronic device 100 can then be used to examine constituents of the sample. A portion of the light is reflected from the sample to a further optical lens 161. The light passes through the further optical lens 161 and falls on the arrangement 130 comprising the detector elements. The further optical lens 161 in front of the plurality of detector elements may be configured to image the image of the sample under investigation, in particular the light reflected from the sample under investigation, onto the detector elements. Each of the detector elements then measures the intensity of the light falling on the respective detector element.

[0075] Referring to FIG. 4A, in the arrangement 110, each of the emitter elements 120 emits light at a wavelength or in a wavelength range that is different from the wavelength or wavelength range of the light emitted by the other emitter elements 120.

[0076] In contrast, the arrangement 110 shown in FIG. 4B also comprises emitter elements 120a, 120b, 120c, 120d that emit light at the same wavelength or in the same wavelength range, respectively.

[0077] As shown in FIG. 4C, the arrangement 110 comprises four segments 165 of emitter elements 120, each of the emitter elements 120 of each segment 165 emitting light at a wavelength or in a wavelength range that is different from the wavelength or wavelength range of the light emitted by the other emitter elements 120 of the segment 165.

[0078] According to FIG. 5, the housing 164 comprises an opening above the two cavities 162, 163, on each of which one of the two optical lenses 160, 161 is arranged. The housing comprises a circumferential step in the housing for mounting the two optical lenses 160, 161, in which the two optical lenses 160, 161 are inserted. As shown in FIG. 5, the partition wall 166 is part of the housing 164 and, in particular, may be of the same material as the housing and integral therewith. In particular, the partition wall 166 optically separates the first cavity 162 with the arrangement 110 with the emitter elements 120 arranged therein from the second cavity 163 with the arrangement 130 with the detector elements arranged therein.

LIST OF REFERENCE SIGNS

[0079] 10 optoelectronic device [0080] 11 arrangement [0081] 12 emitter element [0082] 13 arrangement [0083] 14 Time-of-Flight Detector Element [0084] 15 integrated circuit [0085] 16 camera lens [0086] 17 sample [0087] 18 arrow [0088] 19 arrow [0089] 20 CMOS detector pixel [0090] 21 photodiode [0091] 22 capacitor [0092] 23 capacitor [0093] 24 switch [0094] 25 switch [0095] 26 switch [0096] 27 node [0097] 28 period [0098] 100 optoelectronic device [0099] 110 arrangement [0100] 120 emitter element [0101] 120a emitter element [0102] 120b emitter element [0103] 120c emitter element [0104] 120d emitter element [0105] 130 arrangement [0106] 160 optical lens [0107] 161 optical lens [0108] 162 first cavity [0109] 163 second cavity [0110] 164 housing [0111] 165 segment [0112] 166 partition wall