Abstract
In an embodiment, an optoelectronic measuring device 1ncludes a first detector configured to provide a first detector signal, a second detector configured to provide a second detector signal, wherein each of the first detector and the second detector is configured to detect electromagnetic radiation, a signal difference determiner configured to generate a difference signal by subtracting the second detector signal from the first detector signal and a spectral filter arranged in a beam path upstream of the second detector, wherein the spectral filter is configured to filter the electromagnetic radiation before detection by the second detector, wherein the optoelectronic measuring device is configured to measure an intensity of the electromagnetic radiation impinging on the optoelectronic measuring device.
Claims
1.-15. (canceled)
16. An optoelectronic measuring device comprising: a first detector configured to provide a first detector signal; a second detector configured to provide a second detector signal, wherein each of the first detector and the second detector is configured to detect electromagnetic radiation; a signal difference determiner configured to generate a difference signal by subtracting the second detector signal from the first detector signal; and a spectral filter arranged in a beam path upstream of the second detector, wherein the spectral filter is configured to filter the electromagnetic radiation before detection by the second detector, wherein the optoelectronic measuring device is configured to measure an intensity of the electromagnetic radiation impinging on the optoelectronic measuring device.
17. The optoelectronic measuring device of claim 16, wherein the first detector, at least in a portion of its sensitive spectral range, has an identical type of spectral sensitivity in comparison with the second detector.
18. The optoelectronic measuring device of claim 16, wherein the spectral filter is not arranged in a beam path upstream of the first detector so that the spectral filter is not configured to filter the electromagnetic radiation before detection by the first detector.
19. The optoelectronic measuring device of claim 16, wherein the first detector or the second detector comprises a silicon photodiode.
20. The optoelectronic measuring device of claim 16, wherein the spectral filter is intensity attenuating to an extent of at least 50% in a green spectral range.
21. The optoelectronic measuring device of claim 16, wherein the spectral filter is configured so that a mean square deviation between a spectral sensitivity normalized to one of the difference signal for the electromagnetic radiation and a spectral sensitivity V normalized to one of a human eye according to Commission Internationale de l'Eclairage (CIE) 18.2-1983 is less than a mean square deviation between a spectral sensitivity normalized to one of the first detector signal or of the second detector signal for the electromagnetic radiation and a spectral sensitivity normalized to one of a human eye according to CIE 18.2-1983.
22. The optoelectronic measuring device of claim 16, wherein the spectral filter comprises a filter material selected from C.sub.19H.sub.10Cl.sub.2N.sub.6Na.sub.2O.sub.7S.sub.2, a maleimide, a crystal violet, a cyanine dye, gold nanoparticles, or colloidal quantum dots.
23. The optoelectronic measuring device of claim 16, wherein the spectral filter comprises a spin-coated filter material.
24. The optoelectronic measuring device of claim 16, wherein the first detector and the second detector are arranged relative to one another in such a way that a distance between a detection surface of the first detector and a detection surface of the second detector is less than or equal to 5 mm.
25. The optoelectronic measuring device of claim 16, wherein the first detector and the second detector are arranged relative to one another in such a way that a main detection direction of the first detector and a main detection direction of the second detector are at an angle of at most 30 degrees with respect to one another.
26. The optoelectronic measuring device of claim 16, further comprising an optical radiation distributing means configured to distribute the electromagnetic radiation impinging on the optoelectronic measuring device between the first detector and the second detector.
27. A method for measuring the intensity of the electromagnetic radiation, the method comprising: measuring, by the optoelectronic measuring device of claim 16, the intensity of the electromagnetic radiation.
28. A display device comprising: the optoelectronic measuring device of claim 16, wherein the optoelectronic measuring device is configured to detect an ambient brightness and the display device; and a controller configured to control a display brightness of a display element of the display device depending on the difference signal.
29. A motor vehicle comprising: the optoelectronic measuring device of claim 16, wherein the optoelectronic measuring device is configured to detect an ambient brightness; and a controller configured to control a display brightness of a display element of the motor vehicle depending on the difference signal, or control a headlight or a position luminaire of the motor vehicle depending on the difference signal.
30. A method for measuring an intensity of electromagnetic radiation, the method comprising: detecting, by a first detector, the electromagnetic radiation and providing a first detector signal; detecting, by a second detector, the electromagnetic radiation and providing a second detector signal, wherein the electromagnetic radiation is filtered by a spectral filter before detection by the second detector; and generating a difference signal between first detector signal and second detector signal by subtracting the second detector signal from the first detector signal.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0046] Various exemplary embodiments of the solution according to the invention are explained in greater detail below with reference to the drawings.
[0047] In the figures
[0048] FIG. 1 shows an optoelectronic measuring device 1n accordance with a first exemplary embodiment;
[0049] FIG. 2 shows an optoelectronic measuring device 1n accordance with a second exemplary embodiment;
[0050] FIG. 3 shows a distance and an orientation of the detectors of the optoelectronic measuring device 1n accordance with the second exemplary embodiment;
[0051] FIG. 4 shows an optoelectronic measuring device 1n accordance with a third exemplary embodiment;
[0052] FIGS. 5a-5e show spectral sensitivities in association with the optoelectronic measuring device 1n accordance with the third exemplary embodiment;
[0053] FIG. 6 shows a measuring method;
[0054] FIG. 7 shows a display device; and
[0055] FIG. 8 shows a motor vehicle.
DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0056] The optoelectronic measuring device 1 in accordance with the first exemplary embodiment illustrated in FIG. 1 comprises a first detector 10 and a second detector 20. These detectors are both configured to detect electromagnetic radiation L and in the process each outputs a radiation-intensity-dependent detector signal. In this case, the first detector signal of the first detector 10 is transmitted to a signal difference determiner 30 via a first data line 13 and a second detector signal of the second detector 20 is transmitted to the signal difference determiner 30 via a second data line 23. As an alternative thereto, the detector signals can also be transmitted by radio or by means of light signals, for example. The signal difference determiner 30 generates a difference signal by subtracting the second detector signal from the first detector signal. Both detectors 10, 20 detect the electromagnetic radiation L, as mentioned, although a spectral filter 24 is arranged in a beam path S upstream of the second detector 20, such that the electromagnetic radiation is filtered by means of the spectral filter 24 before detection by the second detector 20. In the present exemplary embodiment, the spectral filter 24 is not arranged in the beam path upstream of the first detector 10, such that in the present exemplary embodiment, the electromagnetic radiation S is not filtered by the spectral filter 24 before detection by the first detector 10.
[0057] The optoelectronic measuring device 1 in accordance with a second exemplary embodiment as illustrated in FIG. 2 is constructed analogously to that of the first exemplary embodiment, but comprises further component parts. It additionally comprises a signal output 31, at which the difference signal is output and can be tapped off. This can be done in an electrically conductive manner or by radio or optionally by means of light signals. A control unit 3 is connected to the signal output 31, which control unit suitably processes the difference signal and is not part of the measuring device 1. The control unit 3 can be an interface of a personal computer, for example, by means of which the difference signal is evaluated.
[0058] In the case of the measuring device 1 indicated in FIG. 2, a radiation distributing means 40 is furthermore arranged in the beam path S upstream of the first detector 10 and the second detector 20. Said means is a diffusing plate, which diffusely scatters the incident electromagnetic radiation L, such that both the first detector 10 and the second detector 20 detect the electromagnetic radiation L.
[0059] Instead of or in addition to the diffusing plate, by way of example, an optical wavelength could also be used in order to guide the electromagnetic radiation L to the first and second detectors 10, 20.
[0060] FIG. 3 schematically illustrates the distance and the orientation of the two detectors 10, 20 of the second exemplary embodiment with respect to one another. A distance d between the detection surfaces 11, 21 of the two detectors is just 1 mm and the detection surfaces 11, 21 are at the same time so small that all points of the first and second detection surfaces 11, 21 are situated at a distance r from one another of less than or equal to 3 mm, such that both the first detector 10 and the second detector 20 detect the electromagnetic radiation L. Furthermore, the first detector and the second detector are arranged relative to one another in such a way that a main detection direction 12 of the first detector 10 and a main detection direction 22 of the second detector 20—apart from manufacturing tolerances—are parallel, such that both the first detector 10 and the second detector 20 detect the electromagnetic radiation L.
[0061] The optoelectronic measuring device 1 in accordance with a third exemplary embodiment as illustrated in FIG. 4 is constructed analogously to the optoelectronic measuring device 1 in accordance with the second exemplary embodiment. In the present case, the first detector 10 consists of a silicon photodiode boa and the second detector 20 consists of a silicon photodiode 20a structurally identical thereto. The signal difference determiner 30 comprises an operational amplifier 132 connected with the aid of the resistor 133 in such a way that it regulates a voltage present at the output 31 such that as a result the difference voltage at its two inputs (designated by + and − in FIG. 4) is regulated to zero. The radiation distributing means 40 is not illustrated in the third exemplary embodiment of an optoelectronic measuring device 1 but it can be present. Furthermore, the silicon photodiodes boa, bob can be arranged as described in association with FIG. 3.
[0062] FIG. 5a illustrates the spectral sensitivity g.sub.1(λ) of the first silicon photodiode boa of the third exemplary embodiment normalized to one. The second silicon photodiode bob structurally identical thereto has the same spectral sensitivity in principle. However, the spectral filter 24 is disposed upstream of said silicon photodiode and brings about a wavelength-dependent intensity attenuation, also called spectral intensity attenuation a(λ), of the electromagnetic radiation L. In the present case, said spectral filter is a spectral filter 24 consisting of the commercially available filter material QXL® 570 C2 maleimide. The spectral sensitivity g.sub.2(λ)—likewise illustrated as normalized to one in FIG. 5a—of the second silicon photodiode 20a in combination with the spectral filter 24 is therefore equal to a spectral sensitivity of the second silicon photodiode 20a without spectral filter 24 multiplied by the factor 1−a(λ). The aforementioned spectral sensitivity of the second silicon photodiode 20a without spectral filter is not directly illustrated in FIG. 5a, but corresponds to the illustrated spectral sensitivity g.sub.1(λ) of the first silicon photodiode boa owing to the two silicon photodiodes 10a, 20a being structurally identical. The spectral sensitivity g.sub.3(λ)=g.sub.1(λ)−g.sub.2(λ) of the difference signal which is obtained by subtracting the second detector signal from the first detector signal and is output at the signal output 31 is likewise illustrated as normalized to one in FIG. 5a. It is particularly high for wavelengths around 555 nm, that is to say in a range in which the spectral filter attenuates the intensity of the electromagnetic radiation L greatly or even to the extent of boo percent.
[0063] FIGS. 5b, 5c, 5d and 5e show, with reference to exemplary embodiment 3 in FIG. 4, corresponding spectral sensitivities g.sub.1(λ), g.sub.2(λ) and g.sub.3(λ) for other filter materials, in each case in combination with the silicon photodiodes boa, 20a of exemplary embodiment 3. In these figures:
[0064] FIG. 5a: concerns, as mentioned, a spectral filter consisting of the commercially available filter material QXL® 570 C2 maleimide;
[0065] FIG. 5b: concerns a spectral filter consisting of a dye of the crystal violet type,
[0066] FIG. 5c: concerns a spectral filter consisting of nanoparticles of gold having a typical diameter of 80 nm, said nanoparticles being embedded in a matrix,
[0067] FIG. 5d: concerns a spectral filter consisting of a cyanine dye of the Cy3 type, and
[0068] FIG. 5e: concerns a spectral filter consisting of the commercially available filter material Procion® Red MX-5B.
[0069] The filter materials mentioned above can be spin-coated in particular onto a filter carrier or onto the second silicon photodiode 20a.
[0070] All of the spectral sensitivities g.sub.3(λ) normalized to one of the difference signals as shown in FIGS. 5a to 5e have greater similarity to the likewise shown spectral sensitivity V(λ) normalized to one of the human eye in accordance with the standard CIE 018.2-1983 than the spectral sensitivity g.sub.1(λ) normalized to one of a silicon photodiode. In particular, the mean square deviation between a spectral sensitivity g.sub.3(λ) normalized to one of the difference signal and the spectral sensitivity V(λ) normalized to one of the human eye in accordance with CIE 018.2-1983 is less than the mean square deviation between the spectral sensitivity normalized to one of the first detector signal g.sub.1(λ) and the spectral sensitivity V(λ) normalized to one of the human eye in accordance with CIE 018.2-1983.
[0071] FIG. 6 illustrates a method for measuring the intensity of the electromagnetic radiation L, which method is suitable for the above-described exemplary embodiments of the optoelectronic measuring device.
[0072] The method comprises the step S0: “Start”.
[0073] The method furthermore comprises step S1: “Detecting the electromagnetic radiation L by means of the first detector 10, 10a”. A first detector signal dependent on the intensity of the electromagnetic radiation is provided in this case.
[0074] The method furthermore comprises step S2: “Detecting the electromagnetic radiation L by means of the second detector 20, 20a, wherein the electromagnetic radiation L is filtered by means of the spectral filter 24 before detection by the second detector 20”. A second detector signal dependent on the intensity of the electromagnetic radiation is provided in this case.
[0075] The method furthermore comprises step S3: “Generating the difference signal”. In this case, the second detector signal is subtracted from the first detector signal by means of the signal difference determiner 30. Furthermore, in this case, the resulting difference signal can be output via the signal output 31.
[0076] The method furthermore comprises step SE: “End”.
[0077] As described above, the control unit 3 can be an interface of a personal computer, by means of which e.g. the difference signal is evaluated in a measurement laboratory. Furthermore, the measuring device 1 described above in accordance with the exemplary embodiments described above can also be used in a display device 200, for example. Such a display device 200 is illustrated by way of example in FIG. 7. It comprises a display element 201 in the form of a display and also a measuring device 1 in accordance with one of the exemplary embodiments 1 to 3 described above. The latter is arranged for detecting an ambient brightness. The display device 200 furthermore comprises a control unit 3, which, depending on the difference signal, increases the display brightness of a display element 201 as the ambient brightness increases, such that the display element 201 is very readable in bright surroundings and does not produce glare in dark surroundings. In the present case here the spectral sensitivity of the measuring device 1 is adapted to the sensitivity curve of the human eye by the spectral filter 24.
[0078] The display device 200 can be part of a telephone, tablet, of a smartphone or of a motor vehicle 210, for example.
[0079] Such a motor vehicle is illustrated in FIG. 8. In this case, the measuring device 1 is arranged in the region of the windshield in order here to detect ambient brightness, in particular the intensity of insolation. The display 201 is arranged such that it is visible to the driver, and the control unit 3 is situated in the engine compartment. In the present case, the control unit is not just configured to control the display brightness as described above in association with FIG. 6. Rather, the headlights 211 and the position luminaires 212 of the motor vehicle 210 are furthermore also controlled depending on the difference signal, such that the headlights 211 and the position luminaires 212 are switched off when there is high ambient brightness and are switched on when there is low ambient brightness.
[0080] 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.
