Optical scanning device

Claim 2

An optical scanning device including means for forming a sensing zone, means for focusing a light beam into said sensing zone and means for sensing some of the light scattered from said sensing zone, said scattered light sensing means comprising a photosensor having two sides, a photoreceiving surface on one of said sides, a passageway extending through said photosensor between said sides, said photosensor being situated near said sensing zone and in the path of said light beam with said passageway aligned with said light beam whereby said light beam passes through said passageway and essentially only scattered light impinges upon said photoreceiving surface of said photosensor and a second photosensor without a passageway therethrough situated in the path of said light beam downstream from said first photosensor and in alignment with said passageway in said first photosensor for receiving, and being actuated by, light which passes through said passageway.

Claim 3

The optical scanning device as defined in claim 1 including a light source and circuit means connected to said light source and to said second photosensor for controlling the light output from said light source relative to the light received by said second photosensor.

Claim 4

An optical particle sensing device comprising first means fOr passing a fluid flow stream containing particles through said device including means forming a fluid passageway for said fluid flow stream and an optical passage means extending through and transversely of said fluid passageway for passing a beam of light through said fluid passageway, the space at the intersection of said fluid passageway and said optical passage means defining a view volume, a light source for generating a light beam, a condensor lens and an objective lens positioned between said light source and said first means and in the path of said light beam, an iris which has a predetermined aperture and which is positioned between said condensor lens and said objective lens and in the path of said light beam, said objective lens being adapted to direct the light passing through said aperture of said iris into said view volume, and a photosensor situated in the path of said light beam and near one end of said optical passage means, said photosensor having two sides, a photoreceiving surface on one side thereof and a passageway extending through said photosensor between said sides, said photosensor being arranged so that said photoreceiving surface is in position to receive some of the light scattered by particles passing through said view volume and said photosensor passageway is aligned with said light beam whereby said light beam passes through said photosensor passageway.

Claim 5

An optical particle sensing device comprising first means fOr passing a fluid flow stream containing particles through said device including means forming a fluid passageway for said fluid flow stream and an optical passage means extending through and transversely of said fluid passageway for passing a beam of light through said fluid passageway, the space at the intersection of said fluid passageway and said optical passage means defining a view volume, a light source for generating a light beam, a condensor lens and an objective lens positioned between said light source and said first means and in the path of said light beam, an iris which has a predetermined aperture and which is positioned between said condensor lens and said objective lens and in the path of said light beam, said objective lens being adapted to direct the light passing through said aperture of said iris into said view volume, and a photosensor situated in the path of said light beam and near one end of said optical passage means, said photosensor having two sides, a photoreceiving surface on one side thereof and a passageway extending through said photosensor between said sides, said photosensor being arranged so that said photoreceiving surface is in position to receive some of the light scattered by particles passing through said view volume and said photosensor passageway is aligned with said light beam whereby said light beam passes through said photosensor passageway.

Claim 6

The optical particle sensing device as defined in claim 3 wherein said photosensor is a PIN photodiode.

Claim 7

The optical particle sensing device as defined in claim 3 wherein said photoreceiving surface is situated adjacent the periphery of said photosensor passageway and extends radially outwardly from the periphery of said photosensor passageway.

Claim 8

The optical particle sensing device as defined in claim 3 wherein said photoreceiving surface is generally annular extending about said photosensor passageway and is coaxial with the axis of said photosensor passageway.

Claim 9

The optical particle sensing device as defined in claim 3 wherein said photosensor is adjustably mounted in said device whereby the position of said photoreceiving surface can be located flush with a side of said fluid passageway adjacent said view volume or at a predetermined distance from said view volume for sensing light scattered within different given angles from the axis of the path of said light beam.

Claim 10

The optical particle sensing device as defined in claim 3 wherein said photosensor is mounted in said device with said photoreceiving surface flush with a side of said fluid passageway adjacent said view volume.

Claim 11

The optical particle sensing device as defined in claim 3 wherein said photosensor is mounted in said device with said photoreceiving surface positioned at a predetermined distance from said view volume.

Claim 12

The optical particle sensing device as defined in claim 3 wherein said photosensor is positioned to receive forward scattered light on the photoreceiving surface thereof.

Claim 13

The optical particle sensing device as defined in claim 3 wherein said photosensor is positioned to receive back scattered light on the photoreceiving surface thereof.

Claim 14

The optical particle sensing device as defined in claim 3 including a second photosensor without a passageway therethrough positioned in the path of said light beam downstream from said view volume and in alignment with said photosensor passageway in said first photosensor for receiving light which passes through said photosensor passageway.

Claim 15

The optical particle sensing device as defined in claim 12 including control circuit means connected to said light source and to said second photosensor for controlling the light output from said light source relative to the intensity of light received by said second photosensor.