Deposit detector and control device using it

• US 7,002,480 B2
• Filed: 12/25/2001
• Issued: 02/21/2006
• Est. Priority Date: 12/22/2000
• Status: Expired due to Fees

• Current Assignee: Niles Company Limited (Valeo SE)
• Original Assignee: Niles Company Limited (Valeo SE)
• Inventors: Tsunetomo, Keiji, Kobayashi, Fumitoshi, Tokuda, Tatsumi, Yoshida, Harunobu
• Primary Examiner(s): Hofsass, Jeffery
• Assistant Examiner(s): LAI, ANNE VIET NGA
• Application Number:
  US10/451,509
• Publication Number:
  US 20040178760A1
• Time in Patent Office: 1,519 Days
• Field of Search: 250/227.25, 250/214.B, 250/208.1, 250573-574, 340/602, 318/483, 318/DIG.2, 356/239.8, 356/336
• US Class Current: 340/602
• CPC Class Codes: B60S 1/0822 characterized by the arrangement or type of detection means
• CPC Class Codes: B60S 1/0833 Optical rain sensor
• CPC Class Codes: B60S 1/0837 with a particular arrangement of the optical elements
• CPC Class Codes: B60S 1/0844 including a camera
• CPC Class Codes: G01N 2021/157 Monitoring by optical means
• CPC Class Codes: G01N 21/43 by measuring critical angle
• CPC Class Codes: G01N 21/47 Scattering, i.e. diffuse reflection G01N21/25, G01N21/41 take precedence G01N21/55 takes precedence
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: Y10S 318/02 Windshield wiper controls

Abstract

A deposit detector in which deposit on a detection surface has a surface shape effect, and generation of a flashing phenomenon caused by irregular reflection of the light incident on the deposit from the outside is estimated. In a deposit detection mode, light emitted from a light source (10) for total reflection and total-reflected from the detection surface is received by a light-receiving element unit (50). Each element is disposed at such an angle that the light undergoes total reflection when no deposit is present or the condition of total reflection is not satisfied when deposit is present. Further, in a light-scattering deposit detection mode, light emitted from a scattering light source (20) and scattered by the detection surface is received by the light-receiving element unit (50). In an extraneous light quantity increase detection mode, extraneous light is received by the light-receiving element unit (50). Light detection signal generated while changing the mode is analyzed by a deposit estimation unit (60), and deposition of rain drops and increase in incident extraneous light quantity are detected to estimate generation of irregular reflection (flashing phenomenon) caused by the shape effect of deposit.

Claims

1. An object sensor having a light source for total reflection, wherein a sensing surface is an outer surface of a transparent substrate from which incident light emitted from the light source for total reflection and led in the transparent substrate is reflected,

the object sensor comprising:

a light-receiving unit for detecting extraneous light incident from the outside through the sensing surface and reflected light reflected from the sensing surface of the light source for total reflection;

an object sensing unit for detecting a reduction change in signal level due to the change of the reflection condition on the sensing surface by an object in a light detection signal detected by the light-receiving unit so as to detect the presence of the object; and

an extraneous light quantity increase detection unit for detecting the presence or absence of the increase, due to a raindrop deposited on the detection surface, of the amount of extraneous light received by the light-receiving unit,

wherein when the presence of an object is detected by the object sensing unit and the increase in the light quantity is detected by the extraneous light quantity increase detection unit, the object sensor estimates the occurrence of a flashing phenomenon.

2. The object sensor according to claim 1, wherein the strength of the flashing phenomenon is evaluated in accordance with the increase rate of the quantity of the incident extraneous light detected by the extraneous light quantity increase detection unit.

3. A window wiper apparatus comprising:

the object sensor according to claim 1, which is a sensing surface provided on a windshield of an automobile and which is a rain sensor for detecting the presence of an object deposited on the windshield;

a window wiper driving unit; and

a window wiper control unit,

wherein the window wiper control unit changes the way of control of the window wiper driving unit based on the output from the object sensor.

4. An object sensor having a light source for total reflection and a scattering light source, wherein a sensing surface is an outer surface of a transparent substrate from which incident light emitted from the light source for total reflection and led in the transparent substrate is reflected and onto which incident light emitted from the scattering light source and led in the transparent substrate is emitted,

the object sensor comprising:

a light-receiving unit for detecting extraneous light incident from the outside through the sensing surface, reflected light reflected from the sensing surface of the light source for total reflection, and a scattered light scattered from the sensing surface of the scattering light source;

an object sensing unit for detecting the change in signal level by an object from the light source of total reflection in a light detection signal detected by the light-receiving unit so as to detect the presence of an object;

a light-scattering object sensing unit for detecting the change in signal level by an object from the scattering light source in a light detection signal detected by the light-receiving unit so as to detect whether or not the object has a light-scattering property; and

an extraneous light quantity increase detection unit for detecting the presence or absence of the increase of signals by extraneous light received by the light-receiving unit.

5. The object sensor according to claim 4, wherein the strength of the flashing phenomenon is evaluated in accordance with the increase rate of the quantity of the incident extraneous light detected by the extraneous light quantity increase detection unit.

6. The object sensor according to claim 4, wherein when the presence of an object is detected by the object sensing unit, the light-scattering property of the object is not detected by the light-scattering object sensing unit, and the increase in the quantity of the incident extraneous light is detected by the extraneous light quantity increase detection unit, the object sensor estimates that a flashing phenomenon occurs due to the shape effect of the object.

7. The object sensor according to claim 4, wherein the object sensing unit, the light-scattering object sensing unit and the extraneous light quantity increase detection unit are used while switching thereof by turning off the scattering light source when the object sensing unit is operated;

turning off the light source for total reflection when the light-scattering object sensing unit is operated; and

turning off the light source for total reflection and the scattering light source when the extraneous light quantity increase detection unit is operated.

8. A window wiper apparatus comprising:

the object sensor according to claim 4, which is a sensing surface provided on a windshield of an automobile and which is a rain sensor for detecting the presence of an object deposited on the windshield;

a window wiper driving unit; and

a window wiper control unit,

wherein the window wiper control unit changes the way of control of the window wiper driving unit based on the output from the object sensor.

9. An object sensor having a light source for total reflection, wherein a sensing surface is an outer surface of a transparent substrate from which incident light emitted from the light source for total reflection and led in the transparent substrate is reflected

the object sensor comprising:

an image-formation system lens for forming an image of the sensing surface emitted by the light source for total reflection; and

a light-receiving element array comprising a plurality of micro light-receiving elements, receiving light from the image formation-system lens and outputting the light detection signal from the micro light-receiving elements as a signal pattern in which the light detection signals are arranged in accordance with the arrangement of the micro light-receiving elements, wherein

when a portion having a signal pattern that is relatively lower than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by the emitted light from the light source for total reflection, the presence of an object is detected on the sensing surface corresponding to the pattern portion, and

when a portion having a signal pattern that is relatively higher than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by the extraneous light by turning off the light source for total reflection, the object sensor estimates the occurrence of flashing.

10. The object sensor according to claim 9, wherein when the presence of an object is detected and the occurrence of flashing is estimated, the object sensor estimates that the object is a raindrop and that the flashing phenomenon occurs due to the shape effect of the raindrop.

11. A window wiper apparatus comprising:

the object sensor according to claim 9, which is a sensing surface provided on a windshield of an automobile and which is a rain sensor for detecting the presence of an object deposited on the windshield;

a window wiper driving unit; and

a window wiper control unit,

wherein the window wiper control unit changes the way of control of the window wiper driving unit based on the output from the object sensor.

12. An object sensor having a light source for total reflection and a scattering light source, wherein a sensing surface is an outer surface of a transparent substrate from which incident light emitted from the light source for total reflection and led in the transparent substrate is reflected and incident light emitted from the scattering light source and led in the transparent substrate is scattered,

the object sensor comprising:

an image-formation system lens for forming an image of the sensing surface emitted by the light source for total reflection and scattering light source, and

a light-receiving element array comprising a plurality of micro light-receiving elements, receiving light from the image formation-system lens and outputting the light detection signal from the micro light-receiving elements as a signal pattern in which the light-detection signals are arranged in accordance with the arrangement of the micro light-receiving elements, wherein

when a portion having a signal pattern that is relatively lower than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by the emitted light from the light source for total reflection, the presence of an object is detected on the sensing surface corresponding to the pattern portion,

when a portion having a signal pattern that is relatively higher than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by a scattered light from the scattering light source, the presence of a light scattering type object is detected on the sensing surface corresponding to the pattern portion, and,

when a portion having a signal pattern that is relatively higher than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by an extraneous light by turning off the light source for total reflection and scattering light source, the object sensor estimates the occurrence of flashing.

13. The object sensor according to claim 12, wherein when the presence of an object is detected, the presence of a light scattering type object is not detected and the occurrence of flashing is estimated, the object sensor estimates that the object is a raindrop and that a flashing phenomenon occurs due to the shape effect of the raindrop.

14. The object sensor according to claim 12, comprising a switching unit for switching three modes of a mode for turning off the light source for total reflection and the scattering light source, a mode for turning on the light source for total reflection and turning off the scattering light source, and a mode for turning off the light source for total reflection and turning on the scattering light source.

15. A window wiper apparatus comprising:

the object sensor according to claim 12, which is a sensing surface provided on a windshield of an automobile and which is a rain sensor for detecting the presence of an object deposited on the windshield;

a window wiper driving unit; and

a window wiper control unit,

wherein the window wiper control unit changes the way of control of the window wiper driving unit based on the output from the object sensor.

16. A method for detecting an object, wherein a sensing surface is an outer surface of the transparent substrate from which incident light emitted from a light source for total reflection and led in the transparent substrate is reflected,

the method comprising:

performing an object sensing processing for detecting the deposition of a raindrop on the detection surface due to the reduction in signal level due to the change of the reflection condition on the sensing surface based on the reflected light of the light source for total reflection from the detection surface by turning on the light source for total reflection;

performing an extraneous light quantity increase detection processing for detecting the increase of light incident from the outside via the sensing surface by turning off the light source for total reflection; and

estimating the occurrence of a flashing phenomenon when the deposition of a raindrop on the sensing surface is detected in the object sensing processing and the increase in the light quantity is detected in the extraneous light quantity increase detection processing.

17. A method for detecting an object, wherein a sensing surface is an outer surface of the transparent substrate from which incident light emitted from a light source for total reflection and led in the transparent substrate is reflected,

the method comprising:

performing an object sensing processing for detecting the deposition of the raindrop on the detection surface due to the reduction in signal level due to the change of the reflection condition on the sensing surface based on the reflected light of the light source for total reflection from the detection surface turning on the light source for total reflection;

performing a light-scattering object sensing processing for detecting whether or not the object has a light-scattering property by the change in the signal level of the scattered light due to the object on the sensing surface by turning on the light source for scattering;

performing an extraneous light quantity increase detection processing for detecting the increase of light incident from the outside via the sensing surface by turning off the light source for total reflection and the scattering light source, and

when the increase in the light quantity is detected in the extraneous light quantity increase detection processing, estimating that a flashing phenomenon occurs when the deposit of a raindrop on the sensing surface is detected in the object sensing processing and estimating that a flashing phenomenon does not occur when the light scattering property of the object deposited on the sensing surface is detected in the light-scattering object sensing processing.

18. A method for detecting an object, wherein a light source for total reflection is used, and a sensing surface is an outer surface of a transparent substrate from which incident light emitted from the light source for total reflection and led in the transparent substrate is reflected, and,

an image-formation system lens for forming an image of the sensing surface emitted by the light source for total reflection and a light-receiving element array comprising a plurality of micro light-receiving elements for receiving the image formed by the image-formation lens are used,

the method comprising:

producing a signal pattern in which light detection signals from the micro light-receiving elements of the light-receiving element array are arranged in accordance with the arrangement of the micro light-receiving elements;

detecting the presence of an object on the sensing surface corresponding to the pattern portion when a portion having a signal pattern that is relatively lower than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by the emitted light from the light source for total reflection; and

estimating the occurrence of a flashing when a portion having a signal pattern that is relatively higher than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by an extraneous light by turning off the light source for total reflection.

19. A method for detecting an object, wherein a light source for total reflection and a scattering light source are used, and a sensing surface is an outer surface of a transparent substrate from which incident light emitted from the light source for total reflection and led in the transparent substrate is reflected and incident light emitted from the scattering light source and led in the transparent substrate is scattered, and,

an image-formation system lens for forming an image of the sensing surface emitted by the light source for total reflection and the scattering light source and a light-receiving element array comprising a plurality of micro light-receiving elements for receiving the image formed by the image-formation lens are used,

the method comprising:

producing a signal pattern in which light detection signals from the micro light-receiving elements of the light-receiving element array are arranged in accordance with the arrangement of the micro light-receiving elements;

detecting the presence of an object on the sensing surface corresponding to the pattern portion when a portion having a signal pattern that is relatively lower than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by the emitted light from the light source for total reflection;

detecting the presence of the light scattering type object on the sensing surface corresponding to the pattern portion when a portion having a signal pattern that is relatively higher than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by the emitted light from the scattering light source; and

estimating the occurrence of a flashing when a portion having a signal pattern that is relatively higher than the surrounding signal level is detected in the signal pattern obtained by the light-receiving element array by extraneous light by turning off the light source for total reflection and the scattering light source.