GB1602136A - Image-sensing element - Google Patents

Description

(54) IMAGE-SENSING ELEMENT (71) We, GALILEO ELECTRO OPTICS CORP., a corporation organised under the laws of Massachusetts, United States of America, of Galileo Park, Sturbridge, Massachusetts, United States of America, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to fiber optic bundles, such are used in image copiers to form image-sensing elements.

In image copying, it is known to employ a thin image-sensing element to scan one dimension of a two dimensional image, such as a page, this element being composed of a plurality of fiber optic bundles. An early-recognized difficulty with such scanners, however, was the appearance of unexposed black lines on the copy where a gap parallel to the scanning direction appeared at the abutting surfaces between the bundles. A solution was ta form fiber optic bundles having abutting faces out of parallel with the scanning direction.

Hicks U.S. Patent No. 3,196,738 used a "bow tie" shape; others used an arrow shape. These designs spread the effects of inter-bundle gaps across the scanned dimension, and eliminated the unexposed black lines on the copy.

But image transmission through the joint between abutting bundles was still poorer than that through the body of the fiber bundle, owing to the gaps remaining at the corners between abutting faces (e.g., the tip of the arrow) and along the abutting faces where manufacturing errors resulted in a mismatch in the angle between the faces (e.g., the arrow angle). Gaps resulted because no attention was given the relationship between the stacking geometry of the individual optical fibers and the shape of the abutting faces. Fibers were considered to be infinitely small; the abutting were designed to be smooth, although they often were randomly corrugated by inter-fiber crevices; and the angle between faces was chosen only to maximize gap spreading (e.g., with an arrow shape the tip angle was made sharp).

Figures 9 and 10 of Hicks U.S. Patent No.

3,196,738 show for a "bow tie" shape bundle, this absence of geometrical relationship between the fibers and the abutting faces. Where some attention has been given this relationship, in imagescope art, the fibers have been arranged in a square pattern, and the bundles have had rectangular cross-sections, all contributing to poor utility in image copiers since these designs necessarily have inter-bundle gaps parallel to the scanning direction.

According to the present invention there is provided an image-sensing element comprising a plurality of fiber optic bundles arranged in a single layer, each of said bundles consisting of amultiplicity of optical fibers, the fibers being arranged in such a closely-packed natural stack that each pair of axes of abutting fibers define a plane parallel with one of three planes intersecting the others in 60 degree angles, each of said bundles being generally arrow like in shape, and having abutting surfaces the faces of which conform to the natural stacking geometry, two of said faces defining the tail of an arrow, two other faces defining the tip of an arrow, the angle between planes of said tip faces and said tail faces being 120 degrees, said tail faces of one bundle mating with said tip faces of an adjacent bundle, and said abutting faces of said bundles being naturally corrugated, the corrugations conforming to the shape of said optical fibers, thereby assuring that the separation between the axes of any two abutting fibers is the same, whether or not the fibers are in the same bundle.

The above arrangement ensures that the disadvantageous inter-bundle gaps may be virtually eliminated and image transmission uniformity greatly enhanced.

The structure, manufacture and operation of the preferred embodiment of the invention is as follows: Structure The drawing shows the preferred embodiment, which is then described.

1. Drawing The Figure is a partial cross-sectional exploded view, somewhat diagrammatic, of said embodiment.

2. Description Turning now to the Figure, there is shown a partial cross-section of an image-sensing element (10 inches in full length, .006 inch thick, and 1 inch deep), indicated generally at 10. The element is composed of a plurality of fiber optic bundles 12 (roughly 1000); three of the plurality are shown. Each bundle 12 consists of 70 optical fibers 14 (.001 inch diameter) arranged in a closelypacked natural stack. The fibers each have a high-refractive-index core (Schott F-7 flint glass; index of 1.62) and a lower-refractiveindex cladding (Corning 7052 borosilicate glass; index of 1.48), both core and cladding are shown diagrammatically in cross-section by a single circle. The fibers are tacked together along their lines of tangency with adjoining fibers. Air spaces 20 are left between fibers. Three intersecting planes 24, 26, 28 are defined by the axes of adjacent fibers 30, 32, 34. Planes defined by the axes of every other pair of adjacent fibers are parallel with one of planes 24, 26, 28. Plane 24 lies parallel to upper surface 36 and lower surface 37 of the element, and the three planes intersect each other in 60 degree angles.

Each bundle 12 has four abutting faces 38, 40, 42, 44, all of which conform to the natural stacking, i.e., the planes defined by the axes of adjacent fibers on the faces are all parallel-with one of planes 24, 26, 28. In particular, faces 38, 42 conform with plane 26, and faces 40, 44 with plane 28. The corner between faces 38 and 40 is defined by single fiber 48, the corner between faces 42 and 44 by three fibers 50, 52, 54.

Manufacture Conventional precision drawing processes, such as those commonly used to produce imagescopes, are used to manufacture the bundles. First, large diameter optical cane is produced using procedures such as disclosed in Hicks U.S.

Patents Nos. 2,980,957 and 2,992,917.

Seventy canes are then laid into a closelypacked natural stack resembling the fmished bundle and process through a furnace, wherein the bundle is drawn down to its finished size. During the draw, the furnace temperature, draw rate and relative viscosity of the core and cladding are controlled so as to only tack together the cladding of the fibers. Cladding viscosity remains higher than core viscosity, allowing the fiber shape to be maintained. Roughly one thousand bundles are joined end to end along their abutting faces to form the 10inch long image-sensing element. The bundles are firmly joined by a longitudinal compression force, and permanently bonded together by a cured plastics material, such as epoxy resin applied to the upper and lower surfaces of the element.

The arrow shape of the abutting faces facilitates application of a compression force since the bundles will tend only to better align themselves under such a force.

Operation Images are transferred from original to copy by orienting one end of the imagesensing element along one dimension of the original, and the other end along the same dimension of the copy. Then as the original is moved in one direction across the element, and the copy in the opposite direction, the image, properly left-right aligned, is transferred.

Other embodiments are possible within the scope of the description and claims.

WHAT WE CLAIM IS: 1. An image-sensing element comprising a plurality of fiber optic bundles arranged in a single layer, each of said bundles consisting of a multiplicity of optical fibers, the fibers being arranged in such a closely-packed natural stack that each pair of axes of abutting fibers define a plane parallel with one of three planes intersecting the others in 60 degree angles, each of said bundles being generally arrow-like in shape, and having abutting surfaces the faces of which conform to the natural stacking geometry, two of said faces defining the tail of an arrow, two other faces defining the tip of an arrow, the angle between planes of said tip faces and said tail faces being 120 degrees, said tail faces of one bundle mating with said tip faces of an adjacent bundle, and said abutting faces of said bundles being naturally corrugated, the corrugations conforming to the shape of said optical fibers, thereby assuring that the separation between the axes of any two abutting fibers is the same, whether or not the fibers are in the same bundle.

2. An image-sensing element as claimed in claim 1, wherein said optical fibers are tacked together along the tangent lines between adjoining fibers, leaving air spaces in the internal interstices between fibers.

3. An image-sensing element as claimed in either claim I or claim 2, wherein said plurality of fiber optic bundles are held together by cured plastics material.

4. An image-sensing element as claimed in claim 3, wherein said plastics material is

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. Structure The drawing shows the preferred embodiment, which is then described. 1. Drawing The Figure is a partial cross-sectional exploded view, somewhat diagrammatic, of said embodiment. 2. Description Turning now to the Figure, there is shown a partial cross-section of an image-sensing element (10 inches in full length, .006 inch thick, and 1 inch deep), indicated generally at 10. The element is composed of a plurality of fiber optic bundles 12 (roughly 1000); three of the plurality are shown. Each bundle 12 consists of 70 optical fibers 14 (.001 inch diameter) arranged in a closelypacked natural stack. The fibers each have a high-refractive-index core (Schott F-7 flint glass; index of 1.62) and a lower-refractiveindex cladding (Corning 7052 borosilicate glass; index of 1.48), both core and cladding are shown diagrammatically in cross-section by a single circle. The fibers are tacked together along their lines of tangency with adjoining fibers. Air spaces 20 are left between fibers. Three intersecting planes 24, 26, 28 are defined by the axes of adjacent fibers 30, 32, 34. Planes defined by the axes of every other pair of adjacent fibers are parallel with one of planes 24, 26, 28. Plane 24 lies parallel to upper surface 36 and lower surface 37 of the element, and the three planes intersect each other in 60 degree angles. Each bundle 12 has four abutting faces 38, 40, 42, 44, all of which conform to the natural stacking, i.e., the planes defined by the axes of adjacent fibers on the faces are all parallel-with one of planes 24, 26, 28. In particular, faces 38, 42 conform with plane 26, and faces 40, 44 with plane 28. The corner between faces 38 and 40 is defined by single fiber 48, the corner between faces 42 and 44 by three fibers 50, 52, 54. Manufacture Conventional precision drawing processes, such as those commonly used to produce imagescopes, are used to manufacture the bundles. First, large diameter optical cane is produced using procedures such as disclosed in Hicks U.S. Patents Nos. 2,980,957 and 2,992,917. Seventy canes are then laid into a closelypacked natural stack resembling the fmished bundle and process through a furnace, wherein the bundle is drawn down to its finished size. During the draw, the furnace temperature, draw rate and relative viscosity of the core and cladding are controlled so as to only tack together the cladding of the fibers. Cladding viscosity remains higher than core viscosity, allowing the fiber shape to be maintained. Roughly one thousand bundles are joined end to end along their abutting faces to form the 10inch long image-sensing element. The bundles are firmly joined by a longitudinal compression force, and permanently bonded together by a cured plastics material, such as epoxy resin applied to the upper and lower surfaces of the element. The arrow shape of the abutting faces facilitates application of a compression force since the bundles will tend only to better align themselves under such a force. Operation Images are transferred from original to copy by orienting one end of the imagesensing element along one dimension of the original, and the other end along the same dimension of the copy. Then as the original is moved in one direction across the element, and the copy in the opposite direction, the image, properly left-right aligned, is transferred. Other embodiments are possible within the scope of the description and claims. WHAT WE CLAIM IS:

1. An image-sensing element comprising a plurality of fiber optic bundles arranged in a single layer, each of said bundles consisting of a multiplicity of optical fibers, the fibers being arranged in such a closely-packed natural stack that each pair of axes of abutting fibers define a plane parallel with one of three planes intersecting the others in 60 degree angles, each of said bundles being generally arrow-like in shape, and having abutting surfaces the faces of which conform to the natural stacking geometry, two of said faces defining the tail of an arrow, two other faces defining the tip of an arrow, the angle between planes of said tip faces and said tail faces being 120 degrees, said tail faces of one bundle mating with said tip faces of an adjacent bundle, and said abutting faces of said bundles being naturally corrugated, the corrugations conforming to the shape of said optical fibers, thereby assuring that the separation between the axes of any two abutting fibers is the same, whether or not the fibers are in the same bundle.

2. An image-sensing element as claimed in claim 1, wherein said optical fibers are tacked together along the tangent lines between adjoining fibers, leaving air spaces in the internal interstices between fibers.

3. An image-sensing element as claimed in either claim I or claim 2, wherein said plurality of fiber optic bundles are held together by cured plastics material.

4. An image-sensing element as claimed in claim 3, wherein said plastics material is

an epoxy resin, and said epoxy resin is applied t5 the exterior of the assembled element.

5. An image-sensing element substantially as hereinbefore described with referenee to the accompanying drawing.