US-12618971-B2 - Active optical sensor system comprising a light source, at least one optical detector, an optical filter element, and a temperature regulation apparatus with temperature regulation

US12618971B2US 12618971 B2US12618971 B2US 12618971B2US-12618971-B2

Abstract

An active optical sensor system ( 1 ) with temperature regulation comprises a light source ( 2 ), configured to emit light ( 3 ) in the direction of an object ( 4 ), at least one optical detector ( 5 ), configured to detect portions ( 6 ) of the light ( 3 ) reflected from the object ( 4 ), and an optical filter element ( 7 ) arranged in a reception beam path for the reflected portions ( 6 ). The sensor system ( 1 ) comprises a temperature regulating device ( 8 ), configured to regulate a source temperature of the light source ( 2 ) depending on a filter temperature of the filter element ( 7 ).

Inventors

Thorsten Beuth
Sercan Cabuk
Helge Ketelsen

Assignees

VALEO SCHALTER UND SENSOREN GMBH

Dates

Publication Date: 20260505
Application Date: 20200826
Priority Date: 20190826

Claims (13)

1 . An active optical sensor system with a temperature regulation, the active optical sensor system comprising: a light source, which is configured to emit light in a direction of an object; at least one optical detector, which is configured to detect components of the light reflected by the object; an optical filter element arranged in a receiving beam path for the components of the light reflected by the object; and a temperature regulation apparatus, which is configured to regulate a source temperature of the light source in dependence on a filter temperature of the optical filter element.
2 . The active optical sensor system as claimed in claim 1 , wherein the temperature regulation apparatus comprises: a first temperature sensor, which is configured and arranged to generate a first sensor signal that is dependent on the filter temperature; and a second temperature sensor, which is configured and arranged to generate a second sensor signal that is dependent on the source temperature; wherein the temperature regulation apparatus is configured to regulate the source temperature in dependence on the first sensor signal and the second sensor signal.
3 . The active optical sensor system as claimed in claim 2 , wherein the temperature regulation apparatus is configured to: determine a setpoint value for the source temperature in dependence on the first sensor signal; and regulate the source temperature to the setpoint value in dependence on the second sensor signal.
4 . The active optical sensor system as claimed in claim 1 , wherein the temperature regulation apparatus is configured to regulate the source temperature in dependence on a specified first parameter, which describes a temperature-dependent shift in a characteristic wavelength of the light source.
5 . The active optical sensor system as claimed in claim 1 , wherein the temperature regulation apparatus is configured to regulate the source temperature in dependence on a specified second parameter, which describes a temperature-dependent shift in at least one characteristic wavelength of the optical filter element.
6 . The active optical sensor system as claimed in claim 1 , wherein the temperature regulation apparatus is configured to regulate the source temperature in such a way that a temperature-dependent shift in at least one characteristic wavelength of the optical filter element is compensated by a temperature-dependent shift in a characteristic wavelength of the light source.
7 . The active optical sensor system as claimed in claim 1 , wherein the optical filter element has a layer arranged on an active surface of the at least one optical detector.
8 . The active optical sensor system as claimed in claim 1 , wherein the optical filter element comprises a bandpass filter, and an emission wavelength of the light source at a specified reference temperature lies within a band of the bandpass filter.
9 . A method for regulating a temperature of an active optical sensor system, the method comprising: emitting light by a light source in a direction of an object; detecting components of the light reflected by the object; and regulating a source temperature of the light source by a temperature regulation apparatus in dependence on a filter temperature of an optical filter element arranged in a receiving beam path for the components of the light reflected by the object.
10 . The method as claimed in claim 9 , further comprising: generating a first sensor signal in dependence on the filter temperature; generating a second sensor signal in dependence on the source temperature; and regulating the source temperature by the temperature regulation apparatus in dependence on the first sensor signal and the second sensor signal.
11 . The method as claimed in claim 10 , further comprising: determining a setpoint value for the source temperature in dependence on the first sensor signal; and regulating the source temperature to the setpoint value in dependence on the second sensor signal.
12 . The method as claimed in claim 9 , wherein the source temperature is regulated in dependence on: a specified first parameter, which describes a temperature-dependent shift in a characteristic wavelength of the light source; and/or a specified second parameter, which describes a temperature-dependent shift in at least one characteristic wavelength of the optical filter element.
13 . The method as claimed in claim 9 , wherein a temperature-dependent shift in at least one characteristic wavelength of the optical filter element is compensated by generating a corresponding shift in a characteristic wavelength of the light source by regulating the source temperature.

Description

The present invention relates to an active optical sensor system with temperature regulation, which has a light source, which is configured to emit light in the direction of an object, and an optical detector, which is configured to detect components of the light reflected by the object, and an optical filter element, which is arranged in a receiving beam path for the reflected components of the light. The invention further relates to a corresponding method for regulating the temperature of an active optical sensor system. Active optical sensor systems, such as lidar systems, can be mounted on motor vehicles in order to realize various functions of electronic vehicle guidance systems or driver assistance systems. These functions include distance measurements, distance control algorithms, lane keeping assistants, object tracking functions, and so on. An active optical sensor system has a light source for emitting light and an optical detector for receiving reflected components of the light. When the ambient temperature increases, these components of the sensor system heat up, which can lead to mechanical expansion and/or to changes in internal physical parameters of the components. This can result in a shift of an emission wavelength of the light source and/or of a transmission spectrum of a filter element arranged in the receiving beam path. As a rule, however, the shift is different for the filter element and the light source, with the result that, in known active optical sensor systems, filter elements with a very wide transmission range depending on the wavelength are used to ensure that the light having the emission wavelength of the light source is transmitted by the filter element with sufficiently high intensity even when temperature fluctuations occur. However, the larger the wavelength range in which the filter element has a high transmission is, the greater is the influence of noise, for example due to ambient light. This leads to a reduced signal-to-noise ratio and accordingly to a reduced accuracy and reliability of the measurement results of the active optical sensor system. Against this background, it is an object of the present invention to specify an improved concept for an active optical sensor system which leads to a lower influence of noise or to an increased signal-to-noise ratio. According to the invention, this object is achieved by the respective subject matter of the independent claims. Advantageous developments and preferred embodiments are the subject matter of the dependent claims. The improved concept is based on the idea of regulating a source temperature of a light source of the sensor system in dependence on a filter temperature of a filter element of the sensor system. According to an independent aspect of the improved concept, an active optical sensor system with temperature regulation is specified. The sensor system has a light source, which is configured to emit light in the direction of an object, in particular of an object that is located in the surrounding area of the sensor system. The sensor system has at least one optical detector, which is configured to detect components of the light reflected by the object, and an optical filter element, which is arranged in a receiving beam path for the reflected components of the light. The sensor system has a temperature regulation apparatus, which is configured to regulate a source temperature of the light source in dependence on a filter temperature of the filter element. The light source can in particular be designed as a laser, for example as a laser diode. The sensor system can in particular be designed as a lidar system. The at least one detector can be designed, for example, as a photodiode, in particular as an avalanche photodiode. Here and below, the term “light” can be understood to comprise electromagnetic waves in the visible range, infrared range, and/or ultraviolet range. Accordingly, the term “optical” can also be understood to relate to light in this sense. The light which is emitted by the light source is preferably infrared light. An emission wavelength, that is to say a maximum of the emission spectrum of the light source, therefore lies in the infrared spectral range, for example at 905 nm or 1200 nm. The filter element can be designed, for example, as a bandpass filter, wherein the emission wavelength of the light source is within a transmission band of the bandpass filter. The filter element being arranged in the receiving beam path means in particular that light which is incident on an active surface of the at least one optical detector from outside the sensor system has passed through the optical filter element. The source temperature can be a temperature in the immediate surrounding area of the light source, for example a temperature of a housing of the light source or a temperature of a heat sink, i.e. a cooling body on which the light source is arranged or to which the light source is connected in orde