Photoelectric detector with improved clear container feature detection
First Claim
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1. A photodetector system, comprising:
- a photodetector and a light source for placement on a first side of a conveyor of target objects;
a reflector for placement on a second side of the conveyor of target objects;
means operatively associated with said light source for providing a first optical path and a second separate optical path;
said first optical path comprising a first beam of emitted light extending from said light source to said reflector and a first beam of reflected light extending from the reflector back toward said photodetector;
said second separate optical path comprising a second beam of emitted light extending from said light source through a detection zone between the light source and said reflector to said reflector and a second beam of reflected light extending from the reflector back toward said photodetector;
said first and second reflected beams being received to produce first and second signals which are representative of the intensity of light received by said photodetector along said first and second optical paths, respectively;
at least one of said first and second optical paths being affected when an object to be detected is within said detection zone;
a comparator for comparing said first and second signals to a predefined threshold; and
means for determining the presence of said object to be detected within said detection zone when a magnitude of at least one of said first and second signals is less than a predefined threshold.
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Abstract
A photodetector is provided with two light sources and a light sensitive component. The use of two light sources significantly reduces the opportunity of a surface feature, or abnormality, from focusing light back toward the light sensitive component in a manner that could possible cause the photodetector to misinterpret the intensified light as being indicative of the absence of an object in the detection zone. The light sources and light sensitive component can be arranged along an axis which is either parallel to the path of the objects to be detected or perpendicular to their path.
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Citations
25 Claims
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1. A photodetector system, comprising:
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a photodetector and a light source for placement on a first side of a conveyor of target objects; a reflector for placement on a second side of the conveyor of target objects; means operatively associated with said light source for providing a first optical path and a second separate optical path; said first optical path comprising a first beam of emitted light extending from said light source to said reflector and a first beam of reflected light extending from the reflector back toward said photodetector; said second separate optical path comprising a second beam of emitted light extending from said light source through a detection zone between the light source and said reflector to said reflector and a second beam of reflected light extending from the reflector back toward said photodetector; said first and second reflected beams being received to produce first and second signals which are representative of the intensity of light received by said photodetector along said first and second optical paths, respectively; at least one of said first and second optical paths being affected when an object to be detected is within said detection zone; a comparator for comparing said first and second signals to a predefined threshold; and means for determining the presence of said object to be detected within said detection zone when a magnitude of at least one of said first and second signals is less than a predefined threshold. - View Dependent Claims (2, 3, 4, 5)
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6. A photodetector system, comprising:
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a reflector; a first light source, said first light source being positioned to direct a first beam of light in a direction toward said reflector and through a detection zone; a second light source, said second light source being positioned to direct a second beam of light in a direction toward said reflector and through said detection zone; a light sensitive component, said light sensitive component being positioned to provide a first signal which is representative of the intensity of a first reflected beam of light when said first beam of light is reflected back toward said light sensitive component, said light sensitive component being positioned to provide a second signal which is representative of the intensity of a second reflected beam of light when said second beam of light is reflected back toward said light sensitive component; a pulser for alternatively energizing said first and second light sources to alternatively produce said first and second beams of light, at least one of said first and second beams of light being affected when an object to be detected is within said detection zone; a comparator for comparing said first and second signals to a predefined threshold; and means for determining the presence of said object to be detected within said detection zone when a magnitude of at least one of said first and second signals is less than said predefined threshold. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
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14. A photodetector system, comprising:
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a reflector; a first light source, said first light source being positioned to direct a first beam of light in a direction toward said reflector and through a detection zone; a second light source, said second light source being positioned to direct a second beam of light in a direction toward said reflector and through said detection zone, said first and second light sources being light emitting diodes; a light sensitive component, said light sensitive component being positioned to provide a first signal which is representative of the intensity of a first reflected beam of light when said first beam of light is reflected back toward said light sensitive component, said light sensitive component being positioned to provide a second signal which is representative of the intensity of a second reflected beam of light when said second beam of light is reflected back toward said light sensitive component; a pulser for alternatively energizing said first and second light sources to alternatively produce said first and second beams of light, at least one of said first and second beams of light being affected when an object to be detected is within said detection zone; a comparator for comparing said first and second signals to a predefined threshold; and means for determining the presence of said object to be detected within said detection zone when a magnitude of at least one of said first and second signals is less than said predefined threshold. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A photodetector system, comprising:
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a reflector; a first light source, said first light source being positioned to direct a first beam of light in a direction toward said reflector and through a detection zone; a second light source, said second light source being positioned to direct a second beam of light in a direction toward said reflector and through said detection zone, said first and second light sources being light emitting diodes; a light sensitive component, said light sensitive component being positioned to provide a first signal which is representative of the intensity of a first reflected beam of light when said first beam of light is reflected back toward said light sensitive component, said light sensitive component being positioned to provide a second signal which is representative of the intensity of a second reflected beam of light when said second beam of light is reflected back toward said light sensitive component; a pulser for alternatively energizing said first and second light sources to alternatively produce said first and second beams of light, at least one of said first and second beams of light being affected when an object to be detected is within said detection zone, said object to be detected being a partially transparent object; a comparator for comparing said first and second signals to a predefined threshold; and means for determining the presence of said object to be detected within said detection zone when a magnitude of at least one of said first and second signals is less than said predefined threshold, said object to be detected being disposed on a conveyor to move along a path which extends through said detection zone. - View Dependent Claims (22, 23, 24, 25)
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Specification