Optical reading device

Claim 2

An optical read-head for sensing a plurality of marking areas on a document and producing signals in response to the presence or absence of marks in the areas comprising: a. a housing; b. a light source mounted on said housing; c. an elongated single lens formed with a cylindrical lightreceiving lens surface, an angularly disposed internal reflective surface, and a cylindrical light-disbursing lens surface, said lens mounted in said housing and positioned to receive and direct the light from said source onto the marking areas of the document at an acute angle of incidence; d. a plurality of light-sensitive elements mounted within said housing and positioned between the angle of incidence and the angle of reflection such that said light-sensitive elements sense the amount of diffused light reflected from said document and produce a signal representative thereof; and e. shielding means positioned between said lens and said lightsensitive elements to prevent undesired light rays from reaching said sensing elements.

Claim 3

A sealed optical read head for sensing a plurality of marking areas on a document and producing signals in response to the presence or absence of marks in the areas comprising: a. a housing having an opening formed therethrough; b. a light source mounted on said housing; c. a window mounted for closing one end of the opening; d. an elongated single lens formed with a cylindrical light-receiving lens surface, an angularly disposed internal reflective surface, and a light-disbursing lens surface, said lens mounted for closing the other end of the opening, said lens adapted for receiving and directing light rays from said light source through said window and onto the marking areas of the document at an acute angle of incidence; e. a plurality of light-sensing elements mounted within individual pockets provided in said housing, one of said light-sensing elements for each of the areas to be sensed, said light-sensing elements positioned substantially perpendicular to said window between the angle of incidence and the angle of specular reflection whereby said light-sensing elements sense diffused light reflected from the marking areas; f. shielding means positioned between said lens and said light-sensing elements to shield said elements from undesired light rays; and g. sealing means within the opening in said housing to provide substantially dust-free operation.

Claim 4

A sealed optical read head for sensing a plurality of marking areas on a document and producing signals in response to the presence or absence of marks in the areas comprising: a. a housing having an opening formed therethrough; b. a light source mounted on said housing; c. a window mounted for closing one end of the opening; d. an elongated single lens formed with a cylindrical light-receiving lens surface, an angularly disposed internal reflective surface, and a light-disbursing lens surface, said lens mounted for closing the other end of the opening, said lens adapted for receiving and directing light rays from said light source through said window and onto the marking areas of the document at an acute angle of incidence; e. a plurality of light-sensing elements mounted within individual pockets provided in said housing, one of said light-sensing elements for each of the areas to be sensed, said light-sensing elements positioned substantially perpendicular to said window between the angle of incidence and the angle of specular reflection whereby said light-sensing elements sense diffused light reflected from the marking areas; f. shielding means positioned between said lens and said light-sensing elements to shield said elements from undesired light rays; and g. sealing means within the opening in said housing to provide substantially dust-free operation.

Claim 5

A sealed optical read head as claimed in claim 2 wherein said shielding means comprises an elongated strip of opaque tape.

Claim 6

A sealed optical read head as claimed in claim 2 wherein said sealing means comprises an encapsulant which affixes said light-sensing elements within said individual pockets and provides additional shielding of said light-sensing elements from random light rays.