Device for measuring an optical transmission path with compensation transmitter, absorber and spectrally selective receive path filter

Abstract

Device for measuring an optical transmission line - with at least one transmitter (H, 2, 3, 4) and - with a compensation transmitter (K, 9) and - with one receiver (D, 10) and - with a compensation transmitter cavity (CAV_K, 28) and - with a receiver cavity (CAV_D, 28) and - with a bridge (48, B3) and - with a barrier (17, B) and - with an optical path (49, WK) and - with a reflector (R) and - with at least one first optical transmission path (11) which is only partially part of the device, and - with a second optical transmission path (I2), which is only partially part of the device, and - with a receive path filter (FD), - wherein the at least one transmitter (H, 2, 3, 4) emits light with a transmitter wavelength and - wherein the compensation transmitter (K, 9) emits light with a compensation transmitter wavelength and - wherein the at least one transmitter (H, 2, 3, 4) can transmit into the at least one first transmission path (11) and - wherein an object (O), which is not part of the device, can send light into a second optical transmission path (I2) at the end of the at least one first optical transmission path (11) (I) wherein the at least one optical receive path filter (FD) is located in the second optical transmission path (I2) and - wherein the said compensation transmitter (K, 9) and the receiver (D, 10) are separated by the at least one bridge (48, B3) in such a way that direct irradiation of the receiver (D, 10) by the compensation transmitter (K, 9) is not possible and - wherein the compensation transmitter (K, 9) is placed in the compensation transmitter cavity (CAV_K, 28) and wherein the bridge (48, B3) is part of the wall of the compensation transmitter cavity (CAV_K, 28) and - wherein the receiver (D, 10) is placed in the receiver cavity (CAV_D, 28) and wherein the web (48, B3) is part of the wall of the receiver cavity (CAV_D, 28) and - wherein at least the receiver (D, 10) and the compensation transmitter (K, 9) are optically connected to each other by the at least one optical path (49, WK) in which light can be transferred from the compensation transmitter (K, 9) to the receiver (D, 10) by at least one reflection at the reflector (R) and - wherein at least the transmitter (H, 2, 3, 4) and at least the receiver (D, 10) are separated by at least the barrier (17, B) in such a way that direct irradiation of the receiver (D, 10) by the transmitter (H, 2, 3, 4) is not possible and - wherein the device has an absorber (51, B2, B) and - wherein the absorber (51, B2, B) prevents the emission of light from at least the compensation transmitter (K, 9) in at least one predefined direction and / or in the direction of at least one object (O) to be measured and - wherein the transmitter (H, 2, 3, 4) and the compensation transmitter (K, 9) radiate with different center-of-mass wavelengths and - wherein the receive path filter (FD) has a transmissivity of at least 75% for the wavelength of the light from the transmitter (H, 2, 3, 4), i.e., for the transmitter wavelength, and / or for the wavelength of the radiation to be detected and - wherein the receive path filter (FD) for the wavelength of the light from the compensation transmitter (K, 9), i.e. for the compensation transmitter wavelength, has a transmissivity of at most 25% and - wherein the receiving path filter (FD) has an absorption factor of at least 75% for the wavelength of the light from the compensation transmitter (K, 9), i.e. for the compensation transmitter wavelength.

Description

[0001] The invention relates to a device for measuring an optical transmission path using a special receive path filter and special barriers. Subject matter of the claimed invention

[0002] The invention relates to a device for measuring an optical transmission path. The device comprises at least one transmitter (H, 2, 3, 4), a compensation transmitter (K, 9), a receiver (D, 10), a compensation transmitter cavity (CAV_K, 28), a receiver cavity (CAV_D, 28), a bridge (48, B3), a barrier (17, B), an optical path (49, WK), a reflector (R), at least one first optical transmission path (11), which is only partially part of the device, a second optical transmission path (I2), which is only partially part of the device, and a receive path filter (FD). The at least one transmitter (H, 2, 3, 4) emits light with a transmitter wavelength. The compensation transmitter (K, 9) emits light with a compensation transmitter wavelength. The at least one transmitter (H, 2, 3, 4) can transmit into the at least one first transmission path (11).An object (O), which is not part of the device, can emit light from the end of the at least one first optical transmission path (11) into a second optical transmission path (I2). The at least one optical receiving path filter (FD) is located in the second optical transmission path (I2). The compensation transmitter (K, 9) and the receiver (D, 10) are separated by the at least one bridge (48, B3) such that direct irradiation of the receiver (D, 10) by the compensation transmitter (K, 9) is not possible. The compensation transmitter (K, 9) is located in the compensation transmitter cavity (CAV_K, 28). The bridge (48, B3) is part of the wall of the compensation transmitter cavity (CAV_K, 28). The receiver (D, 10) is located in the receiver cavity (CAV_D, 28). The bridge (48, B3) is part of the wall of the receiving cavity (CAV_D, 28).At least the receiver (D, 10) and the compensation transmitter (K, 9) are optically connected to each other by at least one optical path (49, WK), in which light can be transferred from the compensation transmitter (K, 9) to the receiver (D, 10) by at least one reflection at the reflector (R). At least the transmitter (H, 2, 3, 4) and at least the receiver (D, 10) are separated by at least the barrier (17, B) such that direct irradiation of the receiver (D, 10) by the transmitter (H, 2, 3, 4) is not possible. The device according to the invention is characterized by this. • that the device has an absorber (51, B2, B) and that the absorber (51, B2, B) prevents the emission of light from at least the compensation transmitter (K, 9) in at least one predefined direction and / or in the direction of at least one object (O) to be measured and • that the transmitter (H, 2, 3, 4) and the compensation transmitter (K, 9) radiate with different center-of-mass wavelengths and • that the receive path filter (FD) has a transmissivity of at least 75% for the wavelength of the light from the transmitter (H, 2, 3, 4), i.e., for the transmitter wavelength, and / or for the wavelength of the radiation to be detected, and • that the receive path filter (FD) for the wavelength of the light from the compensation transmitter (K, 9), i.e., for the compensation transmitter wavelength, has a transmissivity of at most 25% and • that the receive path filter (FD) has an absorption factor of at least 75% for the wavelength of the light from the compensation transmitter (K, 9), i.e., for the compensation transmitter wavelength.

[0003] The Fig. 1, Fig. 2, Fig. 3 and Fig. Section 15 relates to the technical teaching of the invention. The following section further explains the context of the invention. Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13 to Fig. 14 serve this purpose. Introduction and State of the Art

[0004] To recognize three-dimensional gestures such as swiping and approach gestures, sensors are needed that are able to detect the position, movement and orientation of hands.

[0005] Besides the use of cameras, the use of simple LED and photodiode-based concepts is of particular interest due to the associated costs.

[0006] A significant problem known from the prior art is the available installation space. Various methods have been developed to increase the robustness of such optical systems against ambient light and other disturbances.

[0007] Systems are known in the prior art in which a generator (G) produces a transmission signal (S5) that feeds a transmitter (H). For reference to the reference numerals, see the figures and the subsequent description. This transmitter (H) transmits into a receiver (D) after passing through the transmission path to be measured, which consists of at least a first partial transmission path (I1) and a second partial transmission path (I2). The receiver output signal (S0) of the receiver (D) is processed by a controller (CT) into a compensation signal (S3), which feeds a compensation transmitter (K). This K typically transmits a linearly superimposed signal via the transmission path (I3) into the receiver (D).The compensation signal (S3) is generated by the controller (CT) from the receiver output signal (S0) and the transmit signal (S5) in such a way that the transmit output signal (S0) no longer contains any components of the transmit signal (S5) except for a control error and the system noise.

[0008] Such systems, hereinafter referred to as HALIOS systems, are particularly robust against sources of interference, such as sunlight, while simultaneously being robust against contamination and receiver drift (D). Such a HALIOS system is known, for example, from DE 10 2010 014 462 A1 or EP 2 418 512 A1.

[0009] In total, two different basic system variants of Halios systems are known from the prior art, which can also be combined, for example, by switching or weighted adjustment of the control properties. Since the first claim refers to these Halios systems in general, a definition of such prior art Halios systems is given below in order to keep the claims concise.

[0010] A Halios system within the meaning of this revelation is characterized by the fact that i. either in the first variant a. it has at least one signal generator (G) that can generate at least one transmit signal (S5) that controls at least one transmitter (H) that transmits into at least one receiver (D), and b. it has at least one controller (CT) that outputs at least one compensation transmit signal (S3) with which at least one compensation transmitter (K) is controlled, which also transmits superimposed signals into at least one of the said receivers (D), and c. that the said controller (CT) forms at least one of the said compensation transmit signals (S3) from at least one receiver output signal (S0) of the said receiver (D) and at least one of the said transmit signals (S5) and d. and that the controller (CT) controls at least one of the said compensation transmitters (K) by means of the said compensation transmit signal (S3) in such a way that the said receiver output signal (S0) of the said receiver (D) contains no components of the transmit signal (S5) except for a control error and system noise. or in the second variant e. it has at least one signal generator (G) that can generate at least one compensation transmit signal (S3) with which at least one compensation transmitter (K) is controlled, which radiates into at least one receiver (D) and f. it has at least one controller (CT) that outputs at least one transmit signal (S5) that controls at least one transmitter (H) which also transmits superimposed signals into at least one receiver (D), and g. that at least one of the said controllers (CT) forms at least one of the said transmitter signals (S5) from at least one receiver output signal (S0) of one of the said receivers (D) and at least one said compensation transmit signal (S3) and h. and that the controller (CT) controls at least one of the said transmitters (H) by means of at least one of the said transmit signal (S5) such that the receiver output signal of the said receiver (D) contains no components of the compensation transmit signal (S3) except for a control error and system noise or i. that it is a hybrid of the first and second variants and ii. that at least the said optical transmitter (H) can transmit into at least one first transmission path (I1), which is only partially part of the device and iii. that at least one object (O), which is not part of the device, can send light at the end of this first optical transmission path (I1) into at least a second transmission path (I2), which is only partially part of the device, which terminates at at least one of said receivers (D), which is part of the device and iv. that at least this receiver (D) can receive at least the transmitted signal (S5) modified by passing through the first transmission path (I1) and / or the second transmission path (I2) and / or by reflection at the object (O) and converts it into at least one receiver output signal (S0) and v. that one of the said controllers (CT), which is part of the device, outputs at least one signal (S4) which can be used outside the device and vi. that this signaling (S4) represents a representative measured value for at least one property of at least one first transmission path (I1) or a second transmission path (I2) or a representative measured value for at least one property of at least one object (O) at the end of said first transmission path (I1) or at the beginning of said second transmission path (I2) and is output via a signaling (S4) at least on request and vii. that this compensation transmitter (K) transmits into at least one third transmission path (I3) which is entirely part of the device and viii. that at least one of the third transmission paths (I3) terminates at at least one of the said receivers (D) and ix. that at least this receiver (D) can receive at least the signal of the said compensation transmitter (K) superimposed with the signal of at least one of the transmitters (H).

[0011] Based on the Fig. 1, Fig. 2 and Fig. Section 3 briefly explains the state of the art in more detail. Fig. Figure 1 shows a compensating optical sensor system (1) consisting of a transmitter (H), a compensation transmitter (K), and a receiver (D). The transmitter (H) transmits a signal to the receiver (D) via an optical transmission path consisting of a first optical transmission path (I1) and a second optical transmission path (I2). The optical signal is reflected and / or transmitted through the object (O) at the interface between the first optical transmission path (I1) and the second optical transmission path (I2). The compensation transmitter (K) also transmits a signal into a third transmission path (I3), at the end of which the receiver (D) is also located. The two transmission paths typically superimpose in a summing and / or multiplying manner, with summation typically being preferred. In this case, the receiver (D) is represented by a photodiode with a resistor.It should be noted that the drawings are only detailed enough to illustrate the operating principle and enable a qualified person to replicate the proposal. The drawings should therefore generally be understood as rough schematic sketches. The receiver output signal (S0) serves as the input signal for a controller (CT). The transmit signal (S5) used to modulate the transmitter (H) is generated by a generator (G), which in many cases is also part of the controller (CT) in the prior art. The controller (CT) generates a compensation transmit signal (S3) from the receiver output signal (S0) and the transmit signal (S5) used to modulate the transmitter (H). This compensation transmit signal is used to modulate the compensation transmitter (K) in such a way that the receiver output signal (S0) typically contains no components of the transmit signal (S5) except for a control error and signal noise.

[0012] An internal control signal (S4) represents a measure of the optical properties of the object (O), such as distance and / or reflectivity, and / or the properties of the first transmission path (I1) and the second transmission path (I2), such as transmittance and / or light transit time through them. In the prior art, it is common to assume that the optical properties of the third transmission path (I3) are known. Furthermore, the Fig. 1. There are still elements that are not yet disclosed in the published prior art and are explained below. Fig. Figure 2 shows a similar system to that of the Fig. 1 with the difference that here the compensation transmitter (K) is driven by the generator (G) and the transmit signal (S5) is regulated by the controller (CT) so that the receiver output signal (S0) typically contains no components of the compensation transmit signal (S3) except for a control error and signal noise. In addition, the Fig. 2. There are still elements that are not yet disclosed in the prior art and are explained below.

[0013] Various methods for operating such a system and for implementing the controller (CT) are known in the prior art. In particular, it is possible to modulate the transmit signal (S5) used to modulate the transmitter (H) or the compensation transmit signal (S3) used to modulate the compensation transmitter (K) monofrequency or band-limited with a lower cutoff frequency f. min and an upper cutoff frequency f max and a center frequency f mitte =(fmax -f min )2+f min and a bandwidth f b =(f max -f min ) / 2 to operate. It is known that the spectrum of the modulation can be controlled, for example, by using spreading codes.

[0014] In another procedure ( Fig. 3) The transmit signal (S5) used to modulate the transmitter (H) and the compensation transmit signal (S3) used to modulate the compensation transmitter (K) are operated at the same modulation frequency and generated by the controller (CT). However, the duty cycles of the typically rectangular signals (S3, S5) are complementary to each other. This means that the transmitter (H) is always modulated or switched on to a higher transmit power by the transmit signal (S5) whenever the compensation transmitter (K) is attenuated or switched off by the compensation transmit signal (S3), and vice versa. In this case, the controller (CT) does not control the amplitude, but rather the duty cycle of the two signals (S3, S5). The controller receives the transmit clock signal from a generator (G). A corresponding device provides Fig. 3 dar.

[0015] However, the prior art does not specify a method for optimally adjusting the operating point of the compensation transmitter.

[0016] If such a Halios system is to be installed in a single small SMD package, various challenges arise with regard to optics and processability.

[0017] If such a system is to be installed in a single small SMD package, various challenges arise with regard to optics and processability.

[0018] Basically, there are two potential transmission paths between each transmitter H, the object O in the transmission path, and the receiver D: the actual useful path (I1 & I2, I3) and a parasitic transmission path. The light from transmitter H should first be sent from transmitter H to object O and from there reflected back onto the photodiode, the receiver D. However, the light from transmitter H should not fall directly onto the photodiode D. For the light from the compensation diode K, the opposite is true: it should only fall directly onto the photodiode D and, if possible, not be scattered onto object O.

[0019] A major problem in integrating such HALIOS systems into a housing is the suppression of such parasitic couplings. Miniaturization exacerbates this problem, which is referred to below as crosstalk.

[0020] For example, such a Halios system is known from WO 2013 113 456 A1, in which the optical fibers in a circuit board are used as a second transmission path (I2) for coupling the compensation transmitter (K) with the receiver. A disadvantage of this design is, in particular, that it cannot be processed in automated pick-and-place machines. Furthermore, the device must always be manually adapted to the individual needs of the customer.

[0021] Combinations of the Halios principle with various known optical functional elements from optical textbooks are known from DE 10 2010 028 967 A1. In particular, a semi-transparent mirror (reference numeral 80 of DE 10 2010 028 967 A1) is disclosed. DE 10 2010 028 967 A1 identifies the problem that the scattered light from the compensation transmitter (reference numeral 32 of DE 10 2010 028 967 A1), when scattered within the device (reference numeral 82 of DE 10 2010 028 967 A1), can reach the object being measured (reference numeral 22 of DE 10 2010 028 967 A1) and then uncontrollably distort the amplitude of the measurement signal at the receiver (reference numeral 70 of DE 10 2010 028 967 A1).

[0022] From DE 10 2006 003 269 A1, a device and a method for measuring the time of flight of light using a Halios system are known, which can be combined with the technical teaching presented here. The problem of crosstalk between the compensation transmitter and the object reflection signal also exists with this device.

[0023] From DE 100 01 955 A1 a device for using a Halios system as a control element. The above problem of crosstalk between the compensation transmitter and the object reflection signal also exists with this device.

[0024] From EP 2 549 652 A2, an arrangement of LEDs in a Halios system is known. The device suffers from the problem that the compensation LED, which serves as the compensation transmitter, is positioned very close to the receiver and therefore can only be supplied with a very low current. The radiation from the compensation LED thus interferes with the object and consequently with the transmission path between transmitter and receiver, referred to below as the first transmission path (I1). Therefore, it also fails to solve the problem described above.

[0025] A Halios system for measuring the wetting of a disk is known from DE 102 56 429 A1. However, this system also fails to solve the crosstalk problem described above.

[0026] Document EP 2 418 512 A1 relates to an optoelectronic measuring arrangement for compensating for ambient light by means of time-sequentially and phase-shifted clocked transmitting and compensating light sources, a photodiode, an amplifier, a clock generator, a demodulator, and a control unit for zero-drift control of the clock-synchronized input current. It discloses neither structural elements such as separate cavities for the compensating transmitter and receiver with a wall-forming bridge and barrier, nor a defined internal optical path with a reflector between the compensating transmitter and receiver, nor a receiving path filter with the claimed transmission / absorption limits; thus, the structural shielding and spectral-optical filter design of the present device are lacking.

[0027] DE 10 2010 014 462 A1 discloses a control device with an optical sensor unit for user motion detection and consumer control, which uses several transmitting diodes and one receiving diode, processes signal waveforms, and controls consumers such as lamps or blinds via power electronics; structural features such as separate cavities, a bridge, a barrier, a defined internal reflector path, or a specified receiving path filter with transmission / absorption limits are not taught. Claim 1, however, relates to the measurement of an optical transmission path with a transmitter, a compensation transmitter, and a receiver in separate cavities with a bridge / barrier, an optical path including a reflector, and a receiving-side filter with predefined transmissivity and absorption requirements, which clearly distinguishes the teaching functionally and structurally. Task

[0028] The purpose of the proposal is to enable the integration of the various optical sensors and sensor components in a single SMD package, to reduce crosstalk, and to enable optimal illumination and sensitivity of the system. Description of the basic proposal

[0029] The structure and function of the proposed device are described with reference to the attached additional figures.

[0030] To explain the proposal, we will now discuss the technical aspects not disclosed in the published prior art, as these also serve to suppress interference. Many essential elements are already described in documents DE 10 2013 003 791 B4 and WO 2014 131 385 A1, as well as their subsequent international application with the same priority.

[0031] Fig. Figure 1 shows a proposed device. The receiver (D) is symbolized by a photodiode with a series resistor between ground and the supply voltage VDD.

[0032] In addition to the state of the art, among other things, in Fig. Figure 1 shows an optical barrier B that prevents the light from the compensation transmitter, the compensation diode (K), from falling directly onto the object (O). The function of this barrier is as follows: In order for the transmitter (H) to irradiate the object (O) via the first optical transmission path (I1), the barrier (B) must have an optical transmit path window (WH) that is transparent to the radiation, i.e., the wavelength, of the transmitter (H). The wavelength of the transmitter (H) is referred to below as the transmitter wavelength. For the same reason, the barrier (B) must have a second optical receive path window (WD) in the area of ​​the second optical transmission path (I2), which is transparent to the radiation to be detected, and in particular to the wavelength of the radiation to be detected. This wavelength of the radiation to be detected is typically the same wavelength as the radiation of the transmitter (H), i.e., the transmitter wavelength.However, this is not necessarily the case. For example, it is conceivable that the object (O) fluoresces under irradiation from the transmitter (H) and that only this fluorescence is to be measured. In this case, the window in the receive path (WD) is typically chosen so that it is transparent only to the wavelength of this fluorescence radiation, i.e., the fluorescence wavelength. The light from the compensation transmitter (K) should not escape. Therefore, it is advantageous for the receive path window (WD) and the transmit path window (WH) to be opaque to the wavelength of this light from the compensation transmitter (K), i.e., the compensation transmitter wavelength, but preferably absorb it. These windows should also not reflect the light from the compensation transmitter (K) so that the light is eliminated from the system and does not remain in the system through multiple reflections, leading to signal distortions.The receive path window (WD) upstream of the detector must be transparent to the wavelength of the radiation to be detected, typically the transmitter wavelength and / or the fluorescence wavelength, and reliably suppress radiation of the compensation wavelength. In this case, the compensation transmitter (K) advantageously transmits at a different wavelength than the transmitter H. The compensation transmitter wavelength should therefore differ from the transmitter wavelength. The windows are preferably equipped with filters, namely a transmit path filter (FH) for the transmit path and a receive path filter (FD) for the receiver path, to fulfill these transmissivity and reflectivity requirements in an exemplary manner.

[0033] To this end, it is useful to define the terms. In the following, transmissivity refers to the factor by which the intensity (energy) of a light beam with a given center-of-mass wavelength is attenuated when passing through a filter or device component, compared to the intensity (energy) of the incident light beam before passing through the object. For example, with an attenuation of 50%, the transmissivity is 50%.

[0034] In the following, reflectivity refers to the factor by which the intensity (energy) of a light beam with a given center-of-mass wavelength is attenuated upon reflection from a filter or device component, compared to the intensity (energy) of the incident light beam before reflection from the object. For example, a reflectivity of 50% indicates an attenuation of 50%.

[0035] In the following, the absorption factor refers to the factor by which the intensity (energy) of a light beam with a given center-of-mass wavelength is attenuated when reflected by a filter or housing component and simultaneously transmitted through this filter or housing component, compared to the intensity (energy) of the incident light beam before reflection from the object. This energy of the light beam thus remains in the filter or housing component and is neither reflected nor transmitted. For example, with a transmissivity of 25% and a reflectivity of 24%, the absorption factor would be 50%.

[0036] With regard to the device, the transmit path filter (FH) should preferably have a transmissivity of optimally 100%, but at least 50% or better at least 75% or better at least 88% or better at least 95% or better at least 98% or better at least 99% for the wavelength of the light of the transmitter (H), i.e. for the transmitter wavelength.

[0037] The transmit path filter (FH) should preferably have a reflectivity of optimally 0%, but at most 50% or better at most 25% or better at most 12% or better at most 5% or better at most 2% or better at most 1% for the wavelength of the light from the transmitter (H).

[0038] The transmit path filter (FH) should simultaneously preferably have a transmissivity of optimally 0%, but at most 50% or better at most 25% or better at most 12% or better at most 5% or better at most 2% or better at most 1% for the wavelength of the light of the compensation transmitter (K), i.e. for the compensation transmitter wavelength.

[0039] The transmit path filter (FH) should simultaneously preferably have an absorption factor of optimally 100%, but at least 25% or better at least 50% or better at least 75% or better at least 88% or better at least 95% or better at least 98% or better at least 99% for the wavelength of the light of the compensation transmitter (K), i.e. for the compensation transmitter wavelength.

[0040] The receiving path filter (FD) should preferably have a transmissivity of optimally 100%, but at least 50% or better at least 75% or better at least 88% or better at least 95% or better at least 98% or better at least 99% for the wavelength of the light from the transmitter (H), i.e. for the transmitter wavelength, or for the wavelength of the radiation to be detected.

[0041] The receive path filter (FD) should simultaneously preferably have a transmissivity of optimally 0%, but at most 50% or better at most 25% or better at most 12% or better at most 5% or better at most 2% or better at most 1% for the wavelength of the light of the compensation transmitter (K), i.e. for the compensation transmitter wavelength.

[0042] The receive path filter (FD) should preferably have an absorption factor of optimally 100%, but at least 25% or better at least 50% or better at least 75% or better at least 88% or better at least 95% or better at least 98% or better at least 99% for the wavelength of the light of the compensation transmitter (K), i.e. for the compensation transmitter wavelength.

[0043] A high absorption factor for the wavelength of the compensation transmitter (K), i.e. the compensation wavelength, is always preferable to increased reflectivity for both filters.

[0044] This ensures that the receiver (D) is always able to receive both the signal from the compensation transmitter (K), i.e., the compensation transmitting diode, and the signal from the transmitter (H). The receiver (D) must therefore be sensitive to both the compensation wavelength and the wavelength of the radiation to be detected, typically the transmitter wavelength and / or the fluorescence wavelength.

[0045] The use of receive path filters is already known from US 2005 0 184 301 A1 (e.g. Fig. 12, reference numbers 85 to 89 of US 2005 O 184 301 A1). However, their task is only the selection of the incoming and previously measured object (e.g. Fig. 18, reference 146 of US 2005 0 184 301 A1) reflected light from a transmitter (e.g. Fig. 18, reference numbers 132-136 of US 2005 0 184 301 A1). Here in the proposed device, however, it is necessary to ensure, firstly, that the comparably reflected light from the transmitter (H) can enter the proposed device and thus reach the receiver (D), and secondly, that the light from the compensation transmitter (K) cannot escape from the system and can be eliminated from the system as quickly as possible, i.e., with as few reflections within the system as possible.

[0046] If the light from the compensation transmitter (K) could escape, the result would be distorted and the basic coupling, which is extensively discussed, for example, in disclosure EP 2 418 512 A1, would depend on the properties of the object (O) to be measured in the transmission path consisting of the first transmission path (I1) and the second transmission path (I2).

[0047] Furthermore, all materials, including filters and optics, within the device should be designed to exhibit an absorption factor of ideally 100%, or at least 25%, or better, at least 50%, or better, at least 75%, or better, at least 88%, or better, at least 95%, or better, at least 98%, or better, at least 99%, in the following three cases: The spectral ranges with low absorption factors are, firstly, the wavelength of the transmitter (H), i.e., the transmitter wavelength; secondly, the wavelength of the compensation transmitter (K), i.e., the compensation wavelength; and thirdly, the wavelength of the radiation to be detected, i.e., for example, the fluorescence wavelength and / or the wavelength of the transmitter (H).

[0048] This applies especially to wavelengths that produce a signal when irradiated into the receiver (D).

[0049] The materials used for the housing walls should have an absorption factor of ideally 100%, but at least 25%, or better, at least 50%, or better, at least 75%, or better, at least 88%, or better, at least 95%, or better, at least 98%, or better, at least 99%. This does not apply to optically transparent parts, such as lenses, etc.

[0050] This applies especially to wavelengths that produce a signal when irradiated into the receiver (D).

[0051] To prevent the transmitter (H) from directly radiating into the receiver (D), a further barrier (B2), such as that known from EP 2 418 512 A1, is useful. This prevents this or at least lengthens the optical path or otherwise attenuates the unwanted direct signal.

[0052] To ensure that the compensating transmitter (K) can only reach the receiver (D) via reflection from a reflector (R), the receiver is housed in a compensating transmitter cavity (CAV_K) and thus surrounded by a third optical barrier (B3). This barrier features a compensating path window (WK) through which the compensating transmitter (K) can illuminate the receiver (D), which is located in its own receiver cavity (CAV_D), via a reflector (R). The compensating path window (WK) simultaneously functions as an aperture, preventing light from the compensating transmitter (K) from entering other optical paths, such as those that might terminate on the object (O). This is particularly important if the wavelength selectivity of the previously mentioned filters (FD, FH) is insufficient. Fig. Figure 2 shows the proposed device accordingly Fig. 1, where, in contrast to the Fig. 1 the transmitter (H) is regulated instead of the compensation transmitter (K).

[0053] Fig. Figure 3 shows the proposed device accordingly Fig. 1 and Fig. 2, where, in contrast to the Fig. 1 and Fig. 2 the transmitter (H) and the compensation transmitter (K) are controlled by the controller (CT).

[0054] The elements that correspond to the state of the art have been explained above.

[0055] Fig. Figure 4 shows the proposed device in an exemplary top view. In the exemplary device (1), for example, there are three LEDs (2, 3, 4) as transmitters (H) and a photodiode (10) as a receiver (D). Of course, more receivers and a different number of transmitters can be selected. The controller (CT) and, if necessary, the generator (G) must then be adjusted accordingly. The photodiode (9) receives the light reflected back from the transmitters in the form of the LEDs (2, 3, 4) by the object (O). The object (O) is in the Fig. 4 is not shown and is conceptually located above the plane of the drawing in the direction of the viewer. Furthermore, the device (1) contains an integrated preamplifier (8). The device (1) also contains the compensation transmitter (K) in the form of the compensation transmitting diode (9). All elements (2, 3, 4, 10, 9, 8) are mounted on the top of a common connection frame. The electrical connection is made by bonding, preferably gold wire bonding. A barrier (17) is also shown, which acts as a further barrier (B2) that optically separates the transmitters in the form of the LEDs (2, 3, 4) as transmitters (H) from the photodiode (10), which is the receiver (D). Above each of the transmitting diodes (2, 3, 4) is a lens (5, 6, 7) that serves to shape the light beam.

[0056] The packaging technology used is that of a Molded Interconnection Device (MID). In this process, a three-dimensionally formed leadframe is overmolded with injection-molded material. The advantage of this MID technology is the ability to directly implement electrical circuits that would otherwise typically be manufactured using PCB or FPCB technology, without the need for additional materials, solely through the use of a special leadframe structure.

[0057] An integrated evaluation circuit (12) (IC) is placed on the underside of the connection frame for controlling the transmitters in the form of LEDs (2, 3, 4), evaluating the signals from the photodiode (10), controlling the compensation transmitting diode (9), and communicating with the computer of the user system (via S4), for example, a mobile phone. The evaluation circuit (12) thus typically contains the controller (CT). The contacts (e.g., 14) of this evaluation circuit (12) are connected to the contacts (e.g., 13) of the connection frame by bonding. The evaluation circuit (12) is preferably located in a recess of the housing so that the bond wires are covered by the molding compound after potting. However, due to the special shape of the connection frame, soldering on this side of the housing is still possible.For handling during assembly, recesses (16) are provided in this example to prevent scratching of the contacts (11) when using a suitable gripping tool that uses these recesses as clamping points.

[0058] As mentioned above, a key problem to be solved is the suppression of parasitic coupling between the transmitters in the form of the LEDs (2, 3, 4) and the receiver in the form of the photodiode (10). For this purpose, the housing has an optical barrier (17) that lengthens the optical path between the transmitters in the form of the LEDs (2, 3, 4) and the photodiode (10), thus reducing coupling via parasitic paths.

[0059] The optical barrier (17) can be designed in a relatively large number of degrees of freedom. In particular, the said barrier (17) can be provided with slightly beveled walls to ensure that the entire housing can be easily removed from an injection mold.

[0060] Fig. Figure 5 shows again the exemplary position and shape of the additional barrier (17) on the top of the housing from two different sides. This lengthens the parasitic optical path.

[0061] Of particular importance are the integrated microlenses in the form of lenses (5, 6, 7, 40). These are positioned above the transmitters in the form of LEDs (2, 3, 4) and the photodiode (10). This shows Fig. 6. The lenses (5, 6, 7, 40) are made of an optically transparent material. On the transmitter side, the lenses (5, 6, 7, 40) ensure the alignment and shape of the light beam (36, 37, 38) emitted by the respective transmitter in the form of the LEDs (2, 3, 4). Fig. 9) in a preferred direction. The centers of gravity (18, 20, 22) of the transmitters in the form of the LEDs (2, 3, 4) are typically offset relative to the respective optical axis (19, 21, 23) of the associated lens (5, 6, 7). Depending on the amount and orientation of the offset of the respective lens (5, 6, 7), the orientation of the beam lobe (36, 37, 38) of the associated transmitter in the form of the associated LED (2, 3, 4) changes. The size and focal length of the respective lens (5, 6, 7) determine the shape of the respective beam lobe (36, 37, 38). The lenses (5, 6, 7, 40) do not necessarily have to be cylindrically symmetrical. It is conceivable that they could also have other shapes, for example, elliptical. The lenses (5, 6, 7, 40) can also have more than two focal lengths. A Fresnel lens design is particularly preferred. Such lenses can be manufactured, for example, by injection molding from transparent plastics.The transparency refers to the radiation used for transmission and reception. Similarly, lenses (40) can be used on the receiver side to form a sensitivity beam. Here, too, the centers of gravity (24) of the photodiodes (10) can be offset relative to the optical axis (25) of the associated lens (40), analogous to the radiation beam forming method described above for the transmitting diodes. In the example in . Fig. However, in Figure 6, this center of gravity (24) and the point of incidence of the optical axis (25) are located one above the other. As explained, this is not necessarily the case depending on the application.

[0062] It is particularly advantageous if the sensitivity lobe(s) are shaped in such a way that the overlap of the sensitivity lobes and the radiation lobes in the area of ​​interest above the sensor is maximized. This maximizes the sensitivity of the system, which is important, for example, for motion detection.

[0063] If the system is to be used for gesture recognition, for example, it is advantageous for the beam lobes (36, 37, 38) to point in different directions. For instance, with three beam lobes, they would each point in directions rotated 120° around the axis perpendicular to the top surface. In this case, a slight overlap of the beam lobes is beneficial, but this overlap should preferably not exceed 60°. Therefore, a beam lobe should not be wider than 240°. The sensitivity lobe should cover the entire relevant area.

[0064] It is particularly advantageous if the respective lens (40) of the respective receiver (D) (photodiode (10)) is transparent only to the wavelengths used for the transmitters in the form of LEDs (2, 3, 4). Furthermore, the wavelengths of the transmitters in the form of LEDs (2, 3, 4) do not have to be identical. It is conceivable that different colors or wavelengths are deliberately chosen for several transmitters in the form of LEDs (2, 3, 4). This makes it possible to produce a miniaturized color sensor. For example, the receiver (D), i.e., the photodiode (10), can be sensitive to optically visible light of all colors and infrared light, and the transmitters in the form of LEDs (2, 3, 4) can consist of three LEDs of the colors red [first LED (2)], blue [second LED (3)], and green [third LED (4)]. For example, an infrared LED can be used as a compensation transmitter (D) and a compensation transmitting diode (9).

[0065] Fig. Figure 7 shows a cross-section through the device. In the case of the exemplary device, the connecting frame is guided on two levels (27, 26). This allows components of different heights to be processed.

[0066] A wall (52) surrounds the cavities (28) into which the components (2, 3, 4, 8, 9, 10, 12) are inserted. On the side of the transmitters (2, 3, 4, 9) and receivers (10), the cavity (28) is typically filled with a transparent potting compound (50) with a high refractive index. In the area of ​​the compensation diode (9), this potting compound (50) is further covered by an optical cover (51), which will be described later.

[0067] Fig. Figure 8 shows a horizontal section through the device. Various leads (29), which are part of the connection frame, are visible. The transmitters (2, 3, 4) are mounted on die pads (32, 33, 34), typically by gluing or soldering. The latter is advantageous when high thermal power needs to be dissipated. The position of the barrier (17) is also shown for better orientation. Some of the leads (29) connect to contacts (11) of the device (1). Internal connections are possible, but they require a support, which is removed after the molding process. The compensation diode (9) is also mounted on a suitable die pad (35). Similarly, the photodiode (10) is mounted on its associated die pad (31), and the preamplifier (8) is mounted on its die pad (30).

[0068] Fig. Figure 9 shows again the various exemplary directions (36, 37, 38) of the radiation lobes of the transmitting diodes (2, 3, 4) of the device (1) and the associated lenses (5, 6, 7, 40). For better orientation, the barrier (17) is again shown.

[0069] To optimize the coupling of light into the lens (5, 6, 7) on the transmitting side, it is advantageous if the underside (41) of the lens (5, 6, 7) is not arranged perpendicular to the lens axis (19, 21, 23), but is tilted at an angle α relative to this perpendicular surface (43). This shows Fig. 10. It has been shown that an angle of 18° for α is particularly advantageous when the transmitting diode is moved 15° off-axis. The lens, for example, has a diameter of approximately 200 µm.

[0070] Fig. Figure 11 shows another horizontal cross-section through the device (1). The recesses (16), which facilitate handling during assembly, are visible. The transmitters (2, 3, 4) are housed in separate transmitter cavities (53, 54, 55). These provide good optical decoupling. The compensation transmitter (K) also has a compensation transmitter cavity (CAV_K), here cavity (57) with the compensation diode (9), which is separated from the corresponding receiver cavity (CAV_D), here cavity (56) for the photodiode (10), by a bridge (48). In a region (49), however, the height of this bridge (48) is modified so that light from the compensation transmitter (K), here the compensation diode (9), can reach the receiver (D), i.e., the photodiode (10), as described below. The cavities are optically open upwards except for the compensation transmitter cavity (CAV_K), here the cavity (57) of the compensation transmitting diode (9).

[0071] The previously mentioned problem of optimal optical coupling between the compensation transmitter (K), here the compensation diode (9), and the receiver (D), here the photodiode (10), remains. This coupling is addressed in the Fig. 12 and Fig. 13 discussed.

[0072] Fig. Figure 12 shows a cross-section of the exemplary device (1) through the compensation transmitter (K), here the compensation diode (9), and the receiver (D), here the photodiode (10). The receiver (D), here the photodiode (10), must be illuminated by the light from the compensation transmitter (K), here the compensation diode (9), preferably from above and not from the side, since the light-sensitive layers of the photodiode (10) are typically located on its surface. This problem is solved in the exemplary device (1) by the compensation transmitter (K), here the compensation diode (9), emitting light upwards.

[0073] Due to the different refractive index between the transparent potting compound (50) and air, light is reflected back into the housing. This reflection occurs when the angle of incidence of the light from the compensation transmitter (K), here the compensation transmitting diode (9), on the interface of the transparent potting compound (50) is so shallow that total internal reflection occurs. This reflected light then naturally falls, as desired, from above onto the receiver (D), the photodiode (10) (see also Fig.13) Light that can travel directly from the compensation transmitter (K), here the compensation transmitting diode (9), to the receiver (D), the photodiode (10), could be scattered by it, fall onto the object (O) to be measured, and fall back onto the photodetector (10), thus interfering with the measurement signal (S4) and the controller (CT). This is prevented by a third barrier (B3), the aforementioned bridge (48), which separates the receiver cavity (CAV_D), here the cavity (56) of the photodiode (10), from the compensation transmitter cavity (CAV_K), here the cavity (57) of the compensation transmitting diode (9). Only light from the compensation transmitter (K), here the compensation transmitting diode (9), which has been reflected at the boundary layer of the transparent cover material (28), can thus fall on the receiver (D), here the photodiode (10).The opening (49) above the bridge (48) for this desired transmission from the compensation transmitter cavity (CAV_K), here cavity (57), to the receiver cavity (CAV_D), here cavity (56), is designed such that the transmitted light illuminates as exclusively as possible the receiver (D), here the photodiode (10). The area (49) thus functions almost like an optical waveguide.

[0074] To prevent indirect irradiation of the object (O) by the compensation transmitter K (compensation transmitting diode (9)), it is necessary to eliminate the light that is not emitted by total reflection onto the receiver (D), here the photodiode (10), from the system of the device (1) as quickly as possible.

[0075] For this purpose, the material of the housing of the device (1) is preferably made of a material that absorbs all radiation in the wavelength ranges in which this radiation can escape from the housing and in all wavelength ranges in which the transmitters, the LEDs (2, 3, 4) and the compensation diode (9) emit.

[0076] Therefore, all surfaces should be as matte as possible to diffusely scatter the small amount of light that is nevertheless reflected. This does not apply to optical surfaces such as the upper boundary layer of the transparent potting compound (50), where total internal reflection is intended, and the surfaces of the optical windows (WD, WH) or filters (FD, FH) or lenses (5, 6, 7, 40).

[0077] Furthermore, an absorber, the optical cover (51), is applied to the upper boundary layer, which absorbs the radiation from the compensation transmitting diode (9), which is not reflected by total internal reflection onto the receiver (D), here the photodiode (10), and would therefore escape uncontrollably from the housing of the device (1), and thus eliminates it from the system.

[0078] The angles and shapes of the housing surfaces should be designed in such a way that multiple reflections cannot result in a light path that ends on the receiver (D), here the photodiode (10).

[0079] Another problem that arises is the reflection at the receiver (D), here the photodiode (10), itself. For the light to enter the receiver (D), here the silicon of the photodiode (10), it must be irradiated at an angle that is as perpendicular as possible, since the speed of light in the material of the receiver (D), and in particular in the silicon of the photodiode (10), is considerably lower than in the waveguide.

[0080] For this purpose, it is advantageous, but not absolutely necessary, to tilt the mounting platform (31) of the receiver (D), here the photodiode (10), relative to the mounting platform (35) of the compensation transmitter (K), here the compensation transmitting diode (9). This tilting would lead to a reduced sensitivity of the receiver (D), here the photodiode (10), with respect to receiving optical radiation reflected back from the object (O). Therefore, it is further advantageous to optimize the coupling into the receiver (D), here the photodiode (10), by means of an inclined prism, as for the transmitters (H), here the transmitting diodes (2, 3, 4).

[0081] Finally, it must be noted that the receiver (D), and in this case specifically the photodiode (10), which is typically made of silicon, may be transparent to a portion of the radiation. In this case, light can be reflected from the underside of the receiver (D), i.e., the photodiode (10). While this increases the efficiency of the receiver, i.e., the photodiode (10), it ultimately leads to a distortion of the receiver output signal (S0). Therefore, it is advantageous to attach the receiver (D), i.e., the photodiode (10), to the mounting platform (31) with an adhesive that absorbs wavelengths that can pass through the receiver (D), i.e., the photodiode (10).

[0082] Finally, the operating point setting will be briefly discussed. A second barrier (B2) is typically located between the transmitter (H) and the compensation transmitter (K), preventing light from the transmitter (H) from entering the compensation path. Preferably, the compensation transmitter (K) is housed in a compensation transmitter cavity (CAV_K), which preferably completely isolates the compensation transmitter (K) from the outside world, except for an optical compensation path window (WK).This optical compensation path window has, among other things, the task of firstly allowing the light from the compensation transmitter (K) to fall only on the receiver (D) and, as it passes through the compensation path, attenuating this light so that, when the compensation transmitter is fully driven, the light from the compensation transmitter falls on the photodiode, i.e., the receiver (D), with approximately the same light intensity as the light from the transmitter (H) under optimal conditions, such as minimum distance of the object (O) from the sensor system, the device (1), and maximum reflectivity of the object (O).This ensures that the electro-optical operating point of the compensation transmitter (K), defined by the illuminance of the signal from the compensation transmitter (K) on the receiver (D) and the electrical power supply of the compensation transmitter (K), for example, the electrical current supplying the compensation transmitter (K), approximately coincides with the corresponding electro-optical operating point of the transmitter (H) at least at one typical operating point. The receiver (D) is also typically largely optically isolated from the outside world by a receiver cavity (CAV_D). Only the aforementioned compensation path window (WK) and a receive path window (WD) allow light to reach the receiver cavity (CAV_D) and thus the receiver (D).It has been shown that it is advantageous for the wall (B) that optically separates the receiver (D) from the object (O), and / or the second barrier (B2), to be equipped with a reflector (R) that scatters the light from the compensation transmitter (K) onto the receiver (D) in such a way that it is illuminated across its entire surface. This is typically necessary because the compensation path window (WK) must typically have a smaller area than the receiver (D), which should be as sensitive as possible. Thus, it is possible to control the light intensity of the signal from the compensation transmitter (K) through the cross-sectional area and the attenuation of the compensation path window (WK) while still illuminating the entire surface of the receiver (D). For this purpose, the scattered light of the reflector (R) should have a diffuse light component that is greater than 5%, better than 10%, better than 25%, better than 50%, better than 75%, better than 85%, better than 90%.

[0083] This makes it possible, particularly with a compensation transmitter (K) of the same type as a transmitter (H), to operate both – compensation transmitter (K) and transmitter (H) – at the same electro-optical operating point for a typical application. The same electro-optical operating point is defined by the same luminous intensity (light energy) of the compensation transmitter (K) and the transmitter (H) at the same optical radiance, integrated over the receiving area of ​​the receiver (D) on the receiver (D). This has the advantage that the temperature coefficients of transmitter (H) and compensation transmitter (K) are the same at this electro-optical operating point, thereby reducing temperature-induced drift of the measurement signal (S4).Since the luminous intensity (light energy emission) of the compensation transmitter (K) and the transmitter (H) depends, for example in the case of LEDs, on the impressed operating current of the LEDs, an equal luminous intensity (light energy emission) corresponds approximately to an equal current operating point. A similar principle applies to the electrical power and / or electrical voltage, depending on how the LEDs are driven.

[0084] The compensation transmitter (K) and the transmitter (H) therefore each emit a light power at at least one system operating point, which is characterized by an object (O) to be measured within a specified object distance to the receiver (D) and by a reflectivity of more than 0% of the light power emitted onto the object (O) by the transmitter (H), which does not deviate from each other by more than 25%, preferably not more than 10%, preferably not more than 5%, preferably not more than 2%, preferably not more than 1% between the compensation transmitter (K) and the transmitter (H).

[0085] Furthermore, it is advantageous to make the receive path window (WD) and / or any associated receive path filter (FD) optically transparent only to the light to be detected. This can be achieved, in particular, by making it transparent to light of the wavelength of the transmitter (H) or the light to be detected, i.e., by attenuating the light of the transmitter (H) or the light to be detected at its center-of-mass wavelength by no more than 50%, preferably no more than 25%, preferably no more than 10%, preferably no more than 5%, preferably no more than 2%, preferably no more than 1%. The wavelength of the light to be detected can differ from the center-of-mass wavelength of the transmitter (H). This is important, for example, when measuring the fluorescence properties of the object (O). The attenuation is calculated as 100% minus the intensity of the light before the receive path filter (FD) divided by the intensity of the light after the receive path filter (FD).Simultaneously, the receive path filter (FD), i.e., the receive path window (WD), should be opaque to light of the interfering wavelength, meaning it should attenuate the interfering light by at least 50% at its center wavelength, preferably more than 75%, better than 90%, better than 95%, better than 98%, and better than 99%. The attenuation is calculated as 100% minus the intensity of the light before the receive path filter (FD) divided by the intensity of the light after the receive path filter (FD). Even better is if these attenuation ratios apply to the integral attenuation of the interfering light in the spectral range in which the receiver (D) is sensitive. It should also be noted that the transmit path typically has a transmit path window (WH), which may be equipped with a transmit path filter (FH). It is advisable to make the transmit path filter (FH) optically transparent only to the light from the transmitter (H).This can be achieved, in particular, by making the filter transparent to light of the transmitter's wavelength (H), i.e., attenuating the transmitter's light (H) at its center wavelength by no more than 50%, preferably no more than 25%, preferably no more than 10%, preferably no more than 5%, preferably no more than 2%, preferably no more than 1%. The attenuation is calculated as 100% minus the intensity of the light before the transmit path filter (FH) divided by the intensity of the light after the transmit path filter (FH). Simultaneously, the transmit path filter (FH), i.e., the transmit path window (WH), should be opaque to light of the wavelength of a typical interfering source, such as a fluorescent tube, i.e., attenuating the interfering source's light at least at its center wavelength by more than 50%, preferably more than 75%, preferably more than 90%, preferably more than 95%, preferably more than 98%, preferably more than 99%.The attenuation is calculated as 100% minus the intensity of the light before the transmit path filter (FH) divided by the intensity of the light after passing through the transmit path filter (FH). Even better is if these attenuation ratios apply to the integral attenuation of the interfering light in the spectral range to which the receiver (D) is sensitive. In this way, the penetration of the interfering light into the system (1) can be prevented or at least reduced. Furthermore, the compensation transmitter can be considered an interfering source if its light can escape from the system, strike the object, and return to the receiver (D) via any path other than the intended compensation path.

[0086] It is therefore advantageous if the compensation transmitter (K) operates on a different wavelength than the transmitter (H), if possible.

[0087] The device is particularly suitable for use in automobiles with increased requirements regarding electromagnetic compatibility. Reference symbol list 1 exemplary device; 2 first LED, as first transmitter (H); 3 second LED, as second transmitter (H); 4 third LED, as third transmitter (H); 5 first lens; 6 second lens; 7 third lens; 8 preamplifiers; 9 Compensation transmitting diode as compensation transmitter (K); 10 Photodiode as receiver (D) 11 contacts; 12 Evaluation circuit, circuit; 13 contacts of the connection frame; 14 contacts of the evaluation circuit (12); 16 recesses; 17 Lippe as a further barrier (B), optical barrier; 18 first focus of the first transmitter in the form of the first LED (2); 19 first optical axis of the first lens (5); 20 second focus of the second transmitter in the form of the second LED (2); 21 second optical axis of the second lens (6); 22 third focus of the third transmitter in the form of the third LED (3); 23 third optical axis of the third lens (7); 24 Focus of the photodiode (10); 25 optical axis of the lens (40) on receiver side; 26 second level of the connection frame; 27 first level of the connection frame; 28 cavities (corresponding to the compensation transmitter cavity CAV_K and the receiver cavity CAV_D); 29 lines; 30 Mounting island of the preamplifier (8); 31 Mounting island of the photodiode (10) as receiver (D); 32 Mounting island of the first LED (2); 33 Mounting island of the second LED (3); 34 Mounting island of the third LED (4); 35 Mounting island of the compensation diode (9) as compensation transmitter (K); 36 first light beam / first beam cone of the first LED (2); 37 second light beam / second beam cone of the second LED (3); 38 third light beam / third beam cone of the third LED (4); 40 lenses on the receiver side; 41 Underside of the lens (5, 6, 7); 43 Area perpendicular to the lens axis (19, 21, 23); 48 Bridge as third barrier (B3); 49 Area of ​​the bridge (48) which is modified in height so that light from the compensation transmitter (K), here the compensation diode (9), can reach the receiver (D), i.e., the photodiode (10), and which serves as a compensation path window (WK); 50 potting compound; 51 optical coverage; 52 Wall (corresponds to the further barrier B2); 53 Transmitter cavity of the first LED (2); 54 Transmitter cavity of the second LED (3); 55 Transmitter cavity of the third LED (4); 56 Receiver cavity of the photodiode (10) as receiver cavity (CAV_D); 57 Cavity for the compensation diode (9) as compensation transmitter cavity (CAV_K); B Barrier; B2 further barrier; B3 third barrier; CAV_D receiver cavity; CAV_K Compensation transmitter cavity; CT controller; D receiver, photodiode; FD receive path filter; FH transmit path filter; G Generator; H Sender; I1 first partial transmission path, first optical transmission path; I2 second partial transmission path, second optical transmission path; I3 third transmission line; K compensation transmitter, compensation diode; O object; R Reflector; S0 receiver output signal; S3 compensation signal; S4 signaling, internal control signal; S5 transmit signal; WD optical receive path window WK Compensation Path Window; WH optical transmit path window;

Claims

[1] Device for measuring an optical transmission line - with at least one transmitter (H, 2, 3, 4) and - with a compensation transmitter (K, 9) and - with one receiver (D, 10) and - with a compensation transmitter cavity (CAV_K, 28) and - with a receiver cavity (CAV_D, 28) and - with a bridge (48, B3) and - with a barrier (17, B) and - with an optical path (49, WK) and - with a reflector (R) and - with at least one first optical transmission path (11) which is only partially part of the device, and - with a second optical transmission path (I2), which is only partially part of the device, and - with a receive path filter (FD), - wherein the at least one transmitter (H, 2, 3, 4) emits light with a transmitter wavelength and - wherein the compensation transmitter (K, 9) emits light with a compensation transmitter wavelength and - wherein the at least one transmitter (H, 2, 3, 4) can transmit into the at least one first transmission path (11) and - wherein an object (O), which is not part of the device, can send light into a second optical transmission path (I2) at the end of the at least one first optical transmission path (11) (I) wherein the at least one optical receive path filter (FD) is located in the second optical transmission path (I2) and - wherein the said compensation transmitter (K, 9) and the receiver (D, 10) are separated by the at least one bridge (48, B3) in such a way that direct irradiation of the receiver (D, 10) by the compensation transmitter (K, 9) is not possible and - wherein the compensation transmitter (K, 9) is placed in the compensation transmitter cavity (CAV_K, 28) and wherein the bridge (48, B3) is part of the wall of the compensation transmitter cavity (CAV_K, 28) and - wherein the receiver (D, 10) is placed in the receiver cavity (CAV_D, 28) and wherein the web (48, B3) is part of the wall of the receiver cavity (CAV_D, 28) and - wherein at least the receiver (D, 10) and the compensation transmitter (K, 9) are optically connected to each other by the at least one optical path (49, WK) in which light can be transferred from the compensation transmitter (K, 9) to the receiver (D, 10) by at least one reflection at the reflector (R) and - wherein at least the transmitter (H, 2, 3, 4) and at least the receiver (D, 10) are separated by at least the barrier (17, B) in such a way that direct irradiation of the receiver (D, 10) by the transmitter (H, 2, 3, 4) is not possible and - wherein the device has an absorber (51, B2, B) and - wherein the absorber (51, B2, B) prevents the emission of light from at least the compensation transmitter (K, 9) in at least one predefined direction and / or in the direction of at least one object (O) to be measured and - wherein the transmitter (H, 2, 3, 4) and the compensation transmitter (K, 9) radiate with different center-of-mass wavelengths and - wherein the receive path filter (FD) has a transmissivity of at least 75% for the wavelength of the light from the transmitter (H, 2, 3, 4), i.e., for the transmitter wavelength, and / or for the wavelength of the radiation to be detected and - wherein the receive path filter (FD) for the wavelength of the light from the compensation transmitter (K, 9), i.e. for the compensation transmitter wavelength, has a transmissivity of at most 25% and - wherein the receiving path filter (FD) has an absorption factor of at least 75% for the wavelength of the light from the compensation transmitter (K, 9), i.e. for the compensation transmitter wavelength.

Images