Picture reading apparatus with flaring light elimination capability

• US 5,604,606 A
• Filed: 04/13/1994
• Issued: 02/18/1997
• Est. Priority Date: 07/06/1990
• Status: Expired due to Term

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Fujita, Kazuhiro, Miyashita, Takaaki
• Primary Examiner(s): Coles, Sr., Edward L.
• Assistant Examiner(s): Stoll, Thomas L.
• Application Number:
  US08/227,174
• Time in Patent Office: 1,042 Days
• Field of Search: 358/471, 358/472, 358/474, 358/475, 358/480, 358/481, 358/482, 358/484, 358/494, 358/496, 250/208.1
• US Class Current: 358/474
• CPC Class Codes: H04N 1/0311 using an array of elements to project the scanned image elements onto the photodetectors H04N1/0318 takes precedence
• CPC Class Codes: H04N 1/0315 using photodetectors and illumination means mounted on separate supports or substrates or mounted in different planes
• CPC Class Codes: H04N 1/0318 Integral pick-up heads, i.e. self-contained heads whose basic elements are a light-source, a lens array and a photodetector array which are supported by a single-piece frame
• CPC Class Codes: H04N 2201/03112 Light source
• CPC Class Codes: H04N 2201/03129 Transparent cover or transparent document support mounted on the head
• CPC Class Codes: H04N 2201/03141 Photodetector lens
• CPC Class Codes: H04N 2201/03145 Photodetector
• CPC Class Codes: H04N 2201/03166 Additional light shielding member
• CPC Class Codes: H04N 2201/03187 Additional optical element

Abstract

A picture reading apparatus with flaring light elimination capability, which includes a light source for emitting light, a contact glass with which a document to be scanned comes in contact, a lens array in which a plurality of lenses for converging the light from the light source are arranged at equal intervals therebetween, a roof mirror array in which a plurality of roof-like reflection surfaces are arranged corresponding to the plurality of lenses, a restricting plate for eliminating undesired light between adjacent lenses of the lens array, a housing in which the roof mirror array and the lens array are accommodated, a sensor, and a separation mirror. The apparatus further includes a light shield layer provided on the contact glass, at a portion other than a reading portion through which the light from the light source passes to scan the document, for eliminating undesired light, other than the converged light effective in supplying a picture signal.

Claims

1. A picture reading apparatus which comprises:

a housing;

a light source located in said housing and emitting light wherein said light source comprises an array of light emitting diodes;

a contact glass against which a document is positionable wherein said light emitting diodes emit light toward said contact glass so that the document is scanned by the emitted light from said light emitting diodes along a main scanning line;

a lens array in which a plurality of lenses are arranged consecutively at equal intervals therebetween along the main scanning line, each of said plurality of lenses converging a reflected light which is reflected from the document through the contact glass;

a roof mirror array, located in said housing and positioned substantially perpendicularly to the light source, in which a plurality of roof-like reflection surfaces reflecting the converged light from the lens array back to the lens array are arranged, corresponding to said plurality of lenses, at equal intervals therebetween along the main scanning line;

a restricting plate provided between said lens array and said roof mirror array and eliminating flaring light between adjacent lenses of said lens array wherein said roof mirror array and said lens array are accommodated in said housing to form said roof mirror lens array;

a sensor located on said housing and receiving the converged light reflected by said roof mirror array so that said received light is converted into a picture signal indicative of a picture contained in the document;

an optical separation mirror located in said housing, said optical mirror reflecting the converged light from the lens array to said sensor separately from an optical path of the light reflected from the document and led to the lens array; and

a light shield layer formed integrally with a surface of the contact glass so as to be spaced from said sensor and be located inside said housing, said light shield layer including a reading portion to which the emitted light from the light emitting diodes is led to pass through the contact glass for scanning the document, said light shield layer being provided at a portion other than said reading portion on said surface of the contact glass wherein said separation mirror, said light emitting diodes, and said light shield layer are located within a lower portion of said housing and wherein an internal space of said housing containing said light emitting diodes is bounded by said contact glass, said light emitting diodes and said separation mirror.

2. The apparatus as claimed in claim 1, wherein said light shield layer is made of a light absorbing material and formed on a top surface of said contact glass.

3. The apparatus as claimed in claim 1, wherein said light shield layer is made of a light absorbing material and formed on a bottom surface of said contact glass.

4. The apparatus as claimed in claim 1, wherein said light shield layer is made of a light absorbing material and formed on both top and bottom surfaces of said contact glass.

12. The apparatus as claimed in claim 1, wherein said light emitting diodes are of a type which emits a diffuse illuminating light.

5. A picture reading apparatus which comprises:

a housing;

a light source located in said housing and emitting light wherein said light source comprises an array of light emitting diodes;

a contact glass against which a document is positionable wherein said light emitting diodes emit light towards said contact glass so that the document is scanned by the emitted light along a main scanning line;

a lens array in which a plurality of lenses are arranged consecutively at equal intervals therebetween along the main scanning line, each of said plurality of lenses converging a reflected light which is reflected from the document through the contact glass;

a roof mirror array, located in said housing and positioned substantially perpendicularly to the light source, in which a plurality of roof-like reflection surfaces reflecting the converged light from the lens array back to the lens array are arranged, corresponding to said plurality of lenses, at equal intervals therebetween along the main scanning line;

a restricting plate provided between said lens array and said roof mirror array and eliminating flaring light between adjacent lenses of said lens array wherein said roof mirror array and said lens array are accommodated in said housing to form a roof mirror lens array;

a sensor located on said housing and receiving the converged light reflected by said roof mirror array, said sensor converting said received light into a picture signal indicative of a picture contained in the document;

an optical separation mirror located in said housing and reflecting the converged light from the lens array to said sensor separately from an optical path of the light reflected from the document and led to the lens array; and

a light shield provided between said light emitting diodes and said separation mirror, said light shield being spaced from both said light emitting diodes and said sensor, said light shield preventing part of the emitted light from said light emitting diodes from entering directly the inside of said roof mirror lens array wherein said separation mirror, said light emitting diodes, and said light shield layer are located within a lower portion of said housing and wherein an internal space in said housing containing said light emitting diodes is bounded by said contact glass, said light emitting diodes and said separation mirror.

6. The apparatus as claimed in claim 5, wherein said light shield means includes a light absorbing layer which is made of a light absorbing material and formed on a surface of said light shield means.

13. The apparatus as claimed in claim 5, wherein said light emitting diodes are of a type which emits a diffuse illuminating light.

7. A picture reading apparatus comprising:

a housing;

a light source located in said housing and wherein said light source comprises an array of light emitting diodes along a main scanning line;

a contact glass with which a document is positionable wherein said light emitting diodes emit light towards said contact glass so that the document is scanned by the emitted light from said light emitting diodes along a main scanning line;

a lens array in which a plurality of lenses are arranged consecutively at equal intervals therebetween along the main scanning line, each of said plurality of lenses converging a reflected light which is reflected from the document through the contact glass;

a roof mirror array located in said housing and positioned substantially perpendicularly to the light source, in which a plurality of roof-like reflection surfaces reflecting the converged light from the lens array back to the lens array are arranged, corresponding to said plurality of lenses, at equal intervals therebetween along the main scanning line;

a restricting plate provided between said lens array and said roof mirror array, said restricting plate eliminating flaring light between adjacent lenses of said lens array wherein said roof mirror array and said lens array are accommodated in said housing to form a roof mirror lens array;

a sensor located on said housing and receiving the converged light reflected by said roof mirror array, said sensor converting said received light into a picture signal indicative of a picture contained in the document;

an optical separation mirror reflecting the converged light from the lens array to said sensor separately from an optical path of the light reflected from the document and led to the lens array; and

a light shield located in said housing and provided between said light emitting diodes and said separation mirror, said shield being spaced from said sensor and preventing part of the emitted light from said light emitting diodes from entering directly the inside of said roof mirror lens array wherein said separation mirror, said light emitting diodes, and said light shield are located within a lower portion of said housing and said light shield is spaced from said light emitting diodes and wherein an internal space of said housing containing said light emitting diodes is bounded by said contact glass, said light emitting diodes and said separation mirror.

8. The apparatus as claimed in claim 7, wherein said light shield means includes a light absorbing layer which is made of a light absorbing material and formed on a surface of said light shield means.

9. The apparatus as claimed in claim 7, wherein said light shield means has a first part formed in contact with said reverse surface of said separation mirror, said light shield means being bent at an intermediate portion thereof to form a L-shaped member including a second part not being in contact with said reverse surface of said separation mirror.

10. The apparatus as claimed in claim 9, wherein said light shield means includes a light absorbing layer which is made of a light absorbing material and formed on a surface of said light shield means.

11. The apparatus as claimed in claim 9, wherein said light shield means has a portion provided between the light emitting diodes and the separation mirror for preventing part of a reflected light, reflected by said light shield means, from entering directly the inside of the roof mirror lens array.

14. The apparatus as claimed in claim 7, wherein said light emitting diodes are of a type which emits a diffuse illuminating light.