Adhering substance detector and controller using the same
First Claim
1. An object sensor comprising:
- a light-emitting unit for emitting light to a transparent substrate, the transparent substrate having a detection surface on which the light emitted from the light-emitting unit and introduced into the transparent substrate is reflected;
a photodetecting unit for receiving the light reflected on the detection surface; and
an object sensing unit for sensing presence of an object on the detection surface by detecting a change in a photodetection signal obtained as a result of photodetection of the photodetecting unit, the change being caused by a change in a reflection condition on the detection surface which is caused by the object, wherein the light-emitting unit and the photodetecting unit are arranged with respect to the transparent substrate so that the reflected light is received by the photodetecting unit, and so that a photodetecting surface of the photodetecting unit and the detection surface form a focusing optical system, the light-emitting unit is a linear or planar light source formed by providing a plurality of light sources at either one or both of ends of a photoconductor, the focusing optical system is a focusing system of equal magnification, and the photodetecting unit includes a plurality of micro-photodetecting elements.
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Accused Products
Abstract
An object sensor is provided, which has a high object detection rate with respect to an object such as a raindrop adhering to a detection surface, and which is capable of detecting the presence/absence of an object with a high sensitivity. A light source 10, a detection surface 110, a focusing lens 40, and a plurality of photodetecting elements of a photodetecting unit 50 form a focusing system of equal magnification that is capable of catching an image in a size smaller than an object to be detected. Light emitted from the light source 10 is incident on the detection surface 110 via a prism 20 at a predetermined incident angle. Without a raindrop 120, the total internal reflection condition is satisfied as shown by a path 140 of a beam, so that the beam is subjected to the total internal reflection. Then, the beam passes through a prism 30, and is focused on a photodetecting surface of the photodetecting unit 50 by the focusing lens 40. On the other hand, with a raindrop 120, the total internal reflection condition is not satisfied as shown by a trail 130 of a beam, so that the beam passes therethrough and is not focused on the photodetecting unit 50. A difference in signal level is determined on the photodetecting element basis, so that an object covering the detection surface 110 is detected.
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Citations
17 Claims
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1. An object sensor comprising:
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a light-emitting unit for emitting light to a transparent substrate, the transparent substrate having a detection surface on which the light emitted from the light-emitting unit and introduced into the transparent substrate is reflected;
a photodetecting unit for receiving the light reflected on the detection surface; and
an object sensing unit for sensing presence of an object on the detection surface by detecting a change in a photodetection signal obtained as a result of photodetection of the photodetecting unit, the change being caused by a change in a reflection condition on the detection surface which is caused by the object, wherein the light-emitting unit and the photodetecting unit are arranged with respect to the transparent substrate so that the reflected light is received by the photodetecting unit, and so that a photodetecting surface of the photodetecting unit and the detection surface form a focusing optical system, the light-emitting unit is a linear or planar light source formed by providing a plurality of light sources at either one or both of ends of a photoconductor, the focusing optical system is a focusing system of equal magnification, and the photodetecting unit includes a plurality of micro-photodetecting elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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Specification