Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
  • B08B7/02—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by distortion, beating, or vibration of the surface to be cleaned
  • B08B7/026—Using sound waves
  • B08B7/028—Using ultrasounds
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/0006—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B3/00—Cleaning by methods involving the use or presence of liquid or steam
  • B08B3/04—Cleaning involving contact with liquid
  • B08B3/10—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration
  • B08B3/12—Cleaning involving contact with liquid with additional treatment of the liquid or of the object being cleaned, e.g. by heat, by electricity or by vibration by sonic or ultrasonic vibrations
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B08—CLEANING
  • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
  • B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
  • B08B7/04—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by a combination of operations
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
  • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
  • H04N23/50—Constructional details
  • H04N23/52—Elements optimising image sensor operation, e.g. for electromagnetic interference [EMI] protection or temperature control by heat transfer or cooling elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60S—SERVICING, CLEANING, REPAIRING, SUPPORTING, LIFTING, OR MANOEUVRING OF VEHICLES, NOT OTHERWISE PROVIDED FOR
  • B60S1/00—Cleaning of vehicles
  • B60S1/02—Cleaning windscreens, windows or optical devices
  • B60S1/46—Cleaning windscreens, windows or optical devices using liquid; Windscreen washers
  • B60S1/48—Liquid supply therefor
  • B60S1/52—Arrangement of nozzles; Liquid spreading means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60S—SERVICING, CLEANING, REPAIRING, SUPPORTING, LIFTING, OR MANOEUVRING OF VEHICLES, NOT OTHERWISE PROVIDED FOR
  • B60S1/00—Cleaning of vehicles
  • B60S1/02—Cleaning windscreens, windows or optical devices
  • B60S1/56—Cleaning windscreens, windows or optical devices specially adapted for cleaning other parts or devices than front windows or windscreens
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
  • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
  • G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
  • G01S7/40—Means for monitoring or calibrating
  • G01S7/4004—Means for monitoring or calibrating of parts of a radar system
  • G01S7/4039—Means for monitoring or calibrating of parts of a radar system of sensor or antenna obstruction, e.g. dirt- or ice-coating
  • G01S7/4043—Means for monitoring or calibrating of parts of a radar system of sensor or antenna obstruction, e.g. dirt- or ice-coating including means to prevent or remove the obstruction

Definitions

• the invention relates to a method for keeping a field of view of an optical surveillance device clear.
• Optical monitoring devices are, for example, cameras, radar devices, laser scanners, infrared cameras. Since optical monitoring devices receive and possibly also emit electromagnetic waves in the visible and invisible wavelength range, it is important that the field of vision of such an optical monitoring device is largely unimpaired in order to obtain the highest possible light yield and the fewest possible scattering effects.
• optically transparent protective panes are generally provided in the relevant wavelength range, which can be cleaned in various ways. This can be done mechanically, manually or automatically, for example by a windshield wiper. Since the field of vision is also impaired, at least at times, by the mechanical means, an alternative possibility is to clean optical monitoring devices using an ultrasonic device.
• EP 3 618 415 A1 shows an optical monitoring device with a cleaning device, by means of which a dome-shaped cover plate is excited by ultrasound and a cleaning liquid is thereby moved from an edge area to a central area of the cover plate.
• a cleaning liquid On the movement paths of the liquid, any buildup on the cover plate is absorbed by the liquid and transported with the liquid.
• the cover pane is cleaned by evaporating the cleaning liquid at a point where the energy of an ultrasonic field is at its maximum. Due to the fact that the cleaning liquid is evaporated on the cover pane, there is the possibility that solid residues remain on the cover pane despite complete evaporation of the liquid.
• the solid residue is present at the point where the cleaning liquid is vaporized. This point can lie in the field of view and, at worst, in the center of the field of view of the optical monitoring device.
• salts can collect on the cover plate.
• the use cycles of such an ultrasonic cleaning process are shortened by the residues described above.
• the cleaning liquid itself can also impair the view through the cover pane if the cleaning liquid is moved to the energy maximum of an ultrasonic field and accumulates there.
• DE 28 09 748 A1 describes a method according to which a cleaning liquid is sprayed onto a surface to be cleaned and the liquid sprayed on is evaporated again to clean the surface. This evaporation can also take place, for example, by using mechanical waves in the frequency range from 20 to 50 kHz.
• US 2012/0 243 093 A1 deals with the application of a fluid, for example through a windshield wiper system of a motor vehicle, and subsequent evaporation of the liquid.
• DE 42 17 559 A1 also describes moistening of the surface to be cleaned by means of fogging, which even occurs intermittently.
• DE 10 2010 041 475 A1 describes a vibration mechanism that vibrates a cover glass so that a washing fluid sprayed onto a cover glass is removed from the cover glass.
• DE 10 2019 123 478 A1, DE 10 2019 130 604 A1 and DE 10 2019 000 306 A1 describe motor vehicle headlights whose surface can be excited by means of ultrasonic waves. The headlights are sprayed (fogged) with liquid via an ejector of a dispenser.
• US 2012/0 117 745 A1 describes the wetting of a surface excited to vibrate by means of ultrasound by means of a spray device.
• US 2014/0 299 748 A1 in turn shows a combination of the application of a fluid with the coupling of ultrasonic waves, with the fluid exiting at discrete outlets of a supply device and partially and intermittently moistening the surface to be cleaned.
• CN 1 01 885 323 A describes a method for operating a headlight cleaning system using moisture present on the headlight.
• the object of the invention is to provide a method with which the clearing of a field of view of an optical monitoring device is further improved and, in particular, solid deposits can be reliably removed.
• the following method steps are provided: forming a closed film of a liquid on the transparent element;
• the energy required for the ultrasonic waves to remove dirt is significantly lower when a liquid is present on the transparent element.
• the formation of a closed liquid film on the transparent element to be cleaned which can be an outer lens or a protective pane of an optical monitoring device, results in the advantage that the optical properties for looking through the transparent element are largely the same.
• the refraction of light waves through the closed film is largely the same.
• the frequency can be set depending on the type of dirt to be removed and the waveform for the ultrasonic excitation can also be selected depending on the dirt to be removed.
• Soiling of the transparent element can be organic or inorganic buildup. For example, insect residues, mineral adhesions, oil films, growths or metallic residues are mentioned here.
• the closed liquid film can be present on the entire surface of the transparent element or on a partial area of the transparent element.
• a closed liquid film is understood to mean that the transparent element is continuously wetted by the liquid, at least in certain areas. A continuous layer of liquid is thus formed on the transparent element, at least in regions.
• the ultrasonic waves can be transmitted at least partially through the surface contact from the transparent element into the liquid film.
• the ultrasonic waves coupled into the transparent element and optionally also into the liquid film stimulate the transparent element and any deposits or dirt on it to vibrate.
• the liquid can enclose deposits on the transparent element and thereby conduct ultrasonic waves coupled into the liquid to the deposit or stimulate the deposits to oscillate through their own oscillation or reduce adhesion to the transparent element.
• the liquid is obtained from precipitation, such as rain, dew or snow.
• the liquid is at least partially vaporized by the ultrasonic waves, with cavitation being able to occur in the liquid in a further embodiment.
• the effect on the impurities or deposits on the transparent element is further intensified, so that even strongly or firmly adhering deposits can be detached or at least partially detached from the transparent element.
• dissolved impurities are transported out of the viewing area by the liquid.
• the liquid is advantageously used in addition to the ultrasonic waves in order to remove the impurities and/or adhesions from the transparent element.
• the transport out of the field of vision of the optical monitoring device is not exclusively provided by the ultrasonic waves, but can be supported or completely taken over by a preferably constant flow of the liquid.
• the energy from the ultrasonic waves is advantageously required for detaching the contaminants and/or adhesions and only in a secondary function for transporting them away after detachment.
• the energy requirement for the ultrasonic waves can thus be dosed in a targeted manner and reduced overall. It can be conceivable, for example, for the ultrasonic waves to be coupled into the transparent element intermittently and/or for the energy input via the ultrasonic waves to be increased intermittently to detach or partially detach contaminants and/or adhesions. In an optional development of the method, it is provided that the ultrasonic waves propagate essentially in an outer layer of the transparent element. Alternatively or additionally, provision can be made for the ultrasonic waves to be in the form of surface waves. This results in the advantage that, in the case of multi-layer transparent elements, such as laminated glass panes, the ultrasonic waves only propagate in the layer on which contamination and/or adhesion may be present. This prevents ultrasonic energy from being released into the non-cleanable interior of a multilayer transparent element, for example when there is a layer change, by reflection or refraction.
• the ultrasonic waves are coupled into the transparent element by at least one ultrasonic transducer.
• the ultrasonic transducer can be arranged on the side of the transparent element to be cleaned or behind it.
• the ultrasonic transducer can be arranged on the layer to be cleaned.
• this can include the transducer also being arranged between the layer to be cleaned and another layer.
• at least one standing wave is formed between at least two ultrasonic transducers.
• the ultrasonic waves are advantageously coupled directly into the transparent element by the ultrasonic transducers, which are preferably arranged on the side of the transparent element on which the ultrasonic wave is intended to propagate, preferably as a surface wave. In this way, losses due to impedance contrasts of intermediate layers and/or elements are prevented.
• the ultrasonic transducers it is also possible for the ultrasonic transducers to be arranged backwards on the side on which the ultrasonic wave is intended to propagate as a surface wave.
• the ultrasonic transducers are arranged between two layers of the transparent element and preferably couple the ultrasonic wave directly into the layer on which the ultrasonic wave is intended to propagate as a surface wave.
• a local energy maximum is generated by the formation of a standing wave, in which the liquid and/or the transparent element has a maximum amplitude.
• the mechanical action on impurities and/or adhesions and on the liquid is greatest in the area in which the energy maximum lies, so that the effects described above occur preferentially here.
• the ultrasonic transducers can preferably be designed in such a way that they have one or more resonance frequencies.
• the ultrasonic transducers can have an electrode configuration that permits one or more resonance frequencies. on in this way, the ultrasonic transducers can be operated efficiently in several frequency ranges. This results in the advantage that different contaminants and/or adhesions can be detached.
• the liquid is supplied to the transparent element from an edge region.
• a component of the liquid is water.
• a cleaning agent is a component of the liquid.
• Water is advantageously suitable as a component, and particularly as a main component, of the liquid because water is readily available and has no special requirements for storage, management and use.
• cleaning agents can chemically remove impurities and/or adhesions from the transparent element, so that less energy is required to be introduced via ultrasonic waves.
• ultrasonic cleaning it can be advantageous that the surface tension of water can be reduced by a cleaning agent. In this way, the connection between the impurities and/or adhesions and the water-based liquid is improved.
• a further development of the method results in a cleaning agent and/or a disinfectant being added to the liquid intermittently or permanently. Provision can also be made for a gas to be added intermittently to the liquid as it is supplied. This results in the advantages described above for the cleaning agent, which also apply to a disinfectant.
• the intermittent admixture or addition of cleaning agent and/or disinfectant advantageously represents a need-based consumption of these additives. In this way, the maintenance intervals for refilling cleaning agent and/or disinfectant can be extended.
• a gas which can be compressed air, for example, dirt that cannot be removed by the liquid and/or the ultrasonic waves can be mobilized.
• the method is optionally designed in that the liquid flows from a first side of the transparent element to a second side of the transparent element and forms a flowing cover layer on the transparent element.
• the flowing cover layer has a constant thickness or film thickness Has.
• the flow of the flowing cover layer is laminar and/or continuous.
• the flow of the liquid is at least partially caused by a gravitational component. The fact that a flow is provided for the liquid results in the advantage that impurities and/or adhesions detached by ultrasonic waves or the liquid itself do not have to be transported out of the field of vision by the ultrasonic waves. The flow of the liquid takes over the transport in an advantageous manner.
• the liquid to be fed in on the first side of the transparent element it being possible in a further development for the liquid to be fed in through one or more outlets on the first side.
• the outlets can be designed as openings in an edge area of a recess in which the transparent element is inserted. Equally, a single opening can be provided, which fans out in the direction of the transparent window, in particular in a trapezoidal manner. In this way, an even wetting of the surface of the transparent element is achieved and the cleaning result is improved by a combined ultrasonic coupling.
• the liquid is fed to the feed line in a circuit.
• the liquid can be processed in the circuit between the inlet and the outlet. In this way, the liquid and in particular optionally added cleaning and/or disinfecting agents can be reused, as a result of which process resources are saved and maintenance intervals can be made correspondingly longer.
• a control unit regulates the supply of the liquid and/or generates a control signal for generating the ultrasonic waves.
• the control unit regulates the addition of cleaning agent and/or disinfectant to the liquid and/or controls the intermittent gas phase.
• the flow of liquid through the control unit is briefly increased spontaneously. All this contributes to a more efficient use of the liquid or to a more efficient use of energy for the ultrasonic excitation.
• a gas phase in the cleaning liquid which can be provided for example by added compressed air, contamination that can be caused by the liquid and / or Do not allow ultrasound waves to be transported away, mobilize them. The same applies to a spontaneous and short-term increased flow of the liquid.
• the transparent element provision is made for the transparent element to be occasionally wetted with the closed film of the liquid.
• the consumption or use of the liquid can be further optimized by wetting the transparent element at times, but preferably completely in this case.
• the transparent element is only wetted with a closed film of the liquid when cleaning of the transparent element is indicated.
• a device for detecting contamination is provided on the transparent element and the transparent element is wetted with the closed film of the liquid when contamination is detected.
• FIG. 1 shows a schematic representation of an optical monitoring device on which the method is carried out
• FIG. 1 shows an optical monitoring device 100 with which the method can be carried out.
• An optical means such as a camera, is used inside a housing 110 for the sake of clarity.
• the housing 1 10 has a viewing window, not shown here, as a transparent element 10.
• the transparent element 10 is arranged on an edge region 130 of the recess 120. In this edge area 130, the liquid is supplied via a supply line 30 and passed through outlets 32 in this edge area 130 onto the transparent element 10.
• the liquid forms a closed film 50 on the transparent element 10 .
• the closed film 50 of the liquid flows due to gravity from the outlets 32 arranged on the first side 14 of the transparent element to inlets 42 which are arranged on a second side 16 of the transparent element 10 opposite the first side 14 in the edge region 130 .
• FIG. 2 shows the transparent element 10 with two ultrasonic transducers 60 , 62 mounted on an outer side 12 of the transparent element 10 .
• the transparent element 10 can be designed as a multilayer element, for example as a laminated glass pane.
• the ultrasonic transducers 60, 62 are in contact with the layer of the transparent element 10 to be cleaned.
• the ultrasonic transducers 60, 62 couple ultrasonic waves 64 into the transparent element.
• the ultrasonic transducers can thus be arranged on the side of the transparent element 10 to be cleaned.
• the ultrasonic transducers 60, 62 it is also possible for the ultrasonic transducers 60, 62 to be arranged backwards on the side on which the ultrasonic wave 64 should preferably propagate as a surface wave.
• the ultrasonic transducers 60, 62 are arranged between two layers of the transparent element 10 and couple the ultrasonic wave 64 preferably directly into the layer on which the ultrasonic wave 64 is intended to propagate as a surface wave .
• the ultrasonic transducers 60, 62 are suitable for transmitting and receiving ultrasonic waves 64.
• a closed film 50 of the liquid is formed on the transparent element 10 through the outlets 32 described in FIG.
• An impurity 70 to be dissolved or removed in a central region of the transparent element 10 is shown schematically in FIG. However, the impurity 70 can be located anywhere on the outside 12 of the transparent element 10 .
• the closed film 50 of the liquid encloses the contamination 70 on all sides and can also flow over the contamination 70 in one embodiment.
• the ultrasonic waves 64 emitted by the ultrasonic transducers 60, 62 are also coupled into the closed film 50 of the liquid by the transparent element 10 and/or by the transducers 60, 62. As a result, both the transparent element 10 and the closed film 50 of the liquid vibrate.
• the impurity 70 is detached from the transparent member 10 by these vibrations.
• the dissolution of the impurity 70 can by increasing the energy input over the Ultrasonic waves 64 are amplified. This leads to partial evaporation 52 of the liquid and/or evaporation of the impurity 70 itself. If the energy input is increased further, cavitation 54 can occur in the liquid and/or the impurity 70, causing the impurity 70 to detach from the transparent element is further supported.
• a gas such as air

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Remote Sensing (AREA)
• Radar, Positioning & Navigation (AREA)
• Electromagnetism (AREA)
• Signal Processing (AREA)
• Multimedia (AREA)
• Optics & Photonics (AREA)
• Water Supply & Treatment (AREA)
• Computer Networks & Wireless Communication (AREA)
• Cleaning By Liquid Or Steam (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2020
  • 2020-09-17 DE DE102020124322.7A patent/DE102020124322A1/de active Pending
• 2021
  • 2021-09-17 WO PCT/EP2021/075696 patent/WO2022058545A1/de active Application Filing
  • 2021-09-17 US US18/026,635 patent/US20240024929A1/en active Pending
  • 2021-09-17 CN CN202180063404.3A patent/CN116438022A/zh active Pending
  • 2021-09-17 JP JP2023514423A patent/JP2023542831A/ja active Pending
  • 2021-09-17 EP EP21778439.6A patent/EP4214002A1/de active Pending
  • 2021-09-17 KR KR1020237008890A patent/KR20230098781A/ko unknown

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