Deposit detector and controller using the detector

• US 7,034,932 B2
• Filed: 09/07/2001
• Issued: 04/25/2006
• Est. Priority Date: 09/08/2000
• Status: Expired due to Fees

• Current Assignee: Niles Company Limited (Valeo SE)
• Original Assignee: Niles Company Limited (Valeo SE)
• Inventors: Tsunetomo, Keiji, Wakisaka, Masahide, Tokuda, Tatsumi, Kobayashi, Fumitoshi, Yoshida, Harunobu, Imanishi, Hideki
• Primary Examiner(s): Rosenberger, Richard A.
• Application Number:
  US10/363,583
• Publication Number:
  US 20030183752A1
• Time in Patent Office: 1,691 Days
• Field of Search: 356/445, 356/239.8, 250/227.25, 318/DIG.2
• US Class Current: 356/239.8
• CPC Class Codes: B60S 1/0818 including control systems responsive to external conditions, e.g. by detection of moisture, dirt or the like
• CPC Class Codes: B60S 1/0833 Optical rain sensor
• CPC Class Codes: G01N 2021/435 Sensing drops on the contact surface
• CPC Class Codes: G01N 2021/556 Measuring separately scattering and specular
• CPC Class Codes: G01N 2021/945 Liquid or solid deposits of macroscopic size on surfaces, e.g. drops, films, or clustered contaminants dust particles and microscopic contaminants in G01N21/94
• 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: G01N 21/4738 Diffuse reflection precedence is given to G01N21/55 - G01N21/57 if specular component is taken into consideration, e.g. also for testing fluids, fibrous materials
• CPC Class Codes: G01N 21/55 Specular reflectivity
• CPC Class Codes: G01N 21/552 Attenuated total reflection
• CPC Class Codes: G01N 21/94 Investigating contamination, e.g. dust G01N21/85 takes precedence
• CPC Class Codes: Y10S 318/02 Windshield wiper controls

Abstract

The present invention provides an object-sensing device capable of estimating the presence of an object attached on a sensing surface, the kind of the object and the state of the object. An image is formed by a lens with light via the sensing surface, and the light is received by a light-receiving element portion in which a plurality of micro-light-receiving elements are arranged. In the object detection mode, totally reflected light from the sensing surface is received by the light-receiving element portion. The components are arranged at an angle that allows total reflection when there is no object, and does not allow the total reflection condition to be satisfied when there is an object. In the light scattering object detection mode, scattered light from the sensing surface is received by the light-receiving element portion. A signal pattern is obtained by joining detection signal levels of the micro-light-receiving elements in accordance with the arrangement of the micro-light-receiving elements. An increase portion or a drop portion of the signal pattern that appears in accordance with the presence of the object or a difference in the state thereof is analyzed, so that the kind and the state of the object such as a rain drop, muddy water, fogging, ice or the like are estimated.

Claims

1. An object-sensing device comprising a light source for total reflection and a light source for scattering,

wherein an outer surface of a transparent substrate is used as a sensing surface on which an incident light admitted into the transparent substrate from the light source for total reflection is reflected, and an incident light admitted into the transparent substrate from the light source for scattering is irradiated,

the light source for total reflection, the transparent substrate and a light receiver are arranged such that the reflected light of the light source for total reflection from the sensing surface can be received by the light receiver, and the light source for scattering and the light receiver are arranged such that scattered light of the light source for scattering from the sensing surface can be received,

the object-sensing device comprising:

an object sensor for detecting a change due to an object in a signal level from the light source for total reflection in a photo detection signal detected by the light receiver so as to detect a presence of the object; and

a light-scattering-object sensor for detecting a change due to an object in a signal level from the light source for scattering in a photo detection signal detected by the light receiver so as to detect whether or not the object is a light scattering object,

wherein the light source for total reflection and the light source for scattering are switched for operation.

2. The object-sensing device according to claim 1, wherein the object sensor and the light-scattering-object sensor receive light from the same detecting surface.

3. The object-sensing device according to claim 1, wherein

when the presence of an object is detected by the object sensor, and the presence of a light scattering object is detected by the light-scattering-object sensor, then the object is estimated to be muddy water, and

when the presence of an object is detected by the object sensor, and the presence of a light scattering object is not detected by the light-scattering-object sensor, then the object is estimated to be a water drop.

4. The object-sensing device according to claim 1,

wherein the light source for scattering and the light receiver are arranged such that scattered light from the sensing surface by the light source for scattering is received, and totally reflected light on the sensing surface is not directly incident to the light receiver in a state where there is no object on the sensing surface.

5. A window wiper device comprising:

the object-sensing device according to claim 1 which is used as a rain sensor for detecting a presence of an object attached on a window shield of an automobile, on which the sensing surface is provided;

a window wiper driver; and

a window wiper controller,

wherein the window wiper controller changes a control of the window wiper driver, based on estimation results with respect to a kind and a state of an object from the object estimating portion.

6. An object-sensing device comprising two types of light sources for total reflection and scattering,

wherein a portion of an outer surface of a transparent substrate is used as a sensing surface on which an incident light admitted into the transparent substrate from the light source for total reflection is reflected, and an incident light admitted into the transparent substrate from the light source for scattering is irradiated,

the object-sensing device comprising:

an imaging lens for forming an image with each of the reflected light by the light source for total reflection and scattered light by the light source for scattering that are incident from the sensing surface,

a light source switch for switching irradiation of the light source for total reflection and irradiation of the light source for scattering; and

a light-receiving element array in which a plurality of micro-light-receiving elements are arranged,

wherein light from the imaging lens is received by the light-receiving element array, a signal pattern in which photo detection signals from each micro-light-receiving element are aligned in accordance with an arrangement of the micro-light-receiving elements is generated, the presence of an object is detected based on the signal pattern obtained from the irradiation of the light source for total reflection, and whether or not the object is a light scattering object is detected based on the signal pattern obtained from the irradiation of the light source for scattering.

7. The object-sensing device according to claim 6, comprising:

an object sensor for detecting that an object is present when a presence of a pattern portion in which a signal level drops relative to neighboring signal levels is detected in the signal pattern, the object being present on the sensing surface corresponding to the pattern portion; and

a light-scattering-object sensor for detecting that a light scattering object is present when a presence of a pattern portion in which a signal level increases relative to neighboring signal levels is detected in the signal pattern, the light scattering object being present on the sensing surface corresponding to the pattern portion,

wherein when the presence of the object is detected by the object sensor, and the presence of the light scattering object is detected by the light-scattering-object sensor, then the object is estimated to be a substance having light scattering properties, and

when the presence of the object is detected by the object sensor, and the presence of the scattering object is not detected by the light-scattering-object sensor, then the object is estimated to be a substance having light transmission properties.

8. The object-sensing device according to claim 6, wherein

a magnitude of the light scattering properties of the object is estimated based on a relative magnitude of a pattern portion exhibiting a relative increase from neighboring signal levels in the signal pattern of the scattered light of the light source for scattering that is detected by the light-scattering-object sensor.

9. The object-sensing device according to claim 6, wherein

a kind and a state of the object are estimated based on a relative change of a pattern portion exhibiting a relative increase from neighboring signal levels in the signal pattern of the scattered light of the light source for scattering that is detected by the light-scattering-object sensor.

10. The object-sensing device according to claim 6, wherein

when a presence of an object is detected by the object sensor, and a presence of a scattering object is detected by the light-scattering-object sensor, then the object is estimated to be muddy water, and

when a presence of an object is detected by the object sensor, and a presence of a scattering object is not detected by the light-scattering-object sensor, then the object is estimated to be a water drop.

11. The object detecting device according to claim 6, wherein

when a presence of an object is detected by the object sensor, and a presence of a scattering object is detected by the light-scattering-object sensor, then the object is estimated to be muddy water, and

a relative magnitude of a pattern portion exhibiting a relative increase of a signal level from neighboring signal levels in the signal pattern of the scattered light of the light source for scattering that is detected by the light-scattering-object sensor is smaller than a predetermined ratio, then it is estimated that the muddy water is dry.

12. The object-sensing device according to claim 6, wherein

when in a signal pattern of the reflected light of the light source for total reflection detected by the object sensor, a signal level drop over the signal pattern is detected, and in a signal pattern of the scattered light of the light source for scattering detected by the light-scattering-object sensor, a signal level increase over the signal pattern is detected, then the object is estimated to be water droplets due to condensation.

13. The object-sensing device according to claim 6, wherein

when in a signal pattern of the reflected light of the light source for total reflection detected by the object sensor, a signal level is dropped over the signal pattern and a change in the signal pattern is not smooth, and in a signal pattern of the scattered light of the light source for scattering detected by the light-scattering-object sensor, a signal level is increased over the signal pattern and a change in the signal pattern is not smooth, then the object is estimated to be ice due to freezing.

14. The object-sensing device according to claim 6,

wherein the light source for scattering, the imaging lens and the light receiver are arranged such that scattered light from the sensing surface by the light source for scattering is received, and totally reflected light on the sensing surface is not directly incident to the light receiver

15. A window wiper device comprising:

the object-sensing device according to claim 6 which is used as a rain sensor for detecting a presence of an object attached on a window shield of an automobile, on which the sensing surface is provided;

a window wiper driver; and

a window wiper controller,

wherein the window wiper controller changes a control of the window wiper driver, based on estimation results with respect to a kind and a state of an object from the object estimating portion.