O
`
`Unlted States Patent [19]
`Steinle et 111.v
`
`llllllllllllllIlllllllllllllllllllllwllllllllIllllllllllllllllllllll
`
`5,300,767
`Apr. 5, 1994
`
`[11] Patent Number:
`[45] Date of Patent:
`
`_
`
`[54] COLOR WAGE SENSING ASSEMBLY WITH
`~MULTIPLE LINEAR SENSORS AND
`ALIGNED FILTERS
`[75] Inventors: Michael J. Steinle, Fort Collins;
`Steven L- Webb, Lowland, both of
`(3019-; HMS D- Neumm, L05 Altos,
`
`5,040,872 8/1991 Steinle ............................... .. 359/637
`5,044,727 9/ 1991 Steinle .
`5,161,008 11/1992 Funk .
`FOREIGN PATENT DOCUMENTS
`36186461“ 12/1927 Fed. Rep. of Germany .
`3936930C1 5/1990 Fed. Rep. of Germany .
`
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`[21] MP1 N0-= 63,838
`[22] Filed:
`M'Y 19’ 1993
`.
`_
`Related US. Application Data
`doned_
`Continuation of Ser. No. 869,273, Apr. 15, 1992, aban-
`
`[63]
`
`[51] Int. CLS ............................................ .. H01J 40/14
`[52] US. Cl. ............................... .. 250/ 208.1;
`_
`25
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`
`1’ 2267; 35184;;
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`[56]
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`4,709,144 11/1987 Vincent .
`4,783,696 11/1988 Neumann et a1. .
`?ilsgzf? :2 :1‘ '
`ass/7s
`4,985,760 1/1991 Maeshima et al. .
`4,994,907 2/1991 Allen ................................... .. 358/75
`5,019,703 5/1991 Boyd et a1
`
`OTHER PUBLICATIONS
`Patent Abstracts of Japan-vol. 2, No. 125 (E-065) Oct.
`20, 1978 & JP-A-53 092 621 (Matsushita Denki Sangyo
`K.K.) 14 Aug. 1978.
`Primary Examiner-David C. Nelms
`Assistant Examiner-Que T. Le
`[57]
`ABSTRACI,
`An optical scannmg dev1ce for generating a data signal
`.
`.
`.
`,
`.
`representative of an object which is scanned comprising
`a light source for illuminating the object; an imaging
`assembly for projecting imaging light from the object
`onto an image plane; a plurality of linear photosensor
`arrays positioned at the image plane for generating light
`sensing signals indicative of the intensity of light in
`different spectral regions impinged thereon; a transpar
`ent plate positioned in adjacent overlying relationship
`with the photosensor arrays; a plurality of ?lter coat
`ings disposed on different regions of the transparent
`plate in alignment the plurality of photosensor arrays
`for ?lteringly transmitting imaging light in the predeter
`mined different spectral regions to the different photo
`Sens“ arrays
`
`22 Claims, 3 Drawing Sheets
`
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`Apple 1056
`U.S. Pat. 8,504,746
`
`

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`U.S. Patent
`
`Apr. 5, 1994
`
`Sheet 1 of 3
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`5,300,767
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`Apr. 5, 1994
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`U.S. Patent
`US. Patent
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`Apr. 5, 1994
`Apr. 5, 1994
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`Sheet 3 of 3
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`5,300,767
`5,300,767
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`
`1
`
`COLOR IMAGE SENSING ASSEMBLY WITH
`MULTIPLE LINEAR SENSORS AND ALIGNED
`FILTERS
`
`5,300,767
`2
`beam, light shining through a second ?lter window
`produces a green beam, and light shining through a
`third ?lter window produces a red beam. The projec
`tion assembly typically includes a number of lenses and
`an aperture forming
`The sensor assembly includes
`three photoelectric sensor arrays. The projection as
`sembly focuses the red beam on the ?rst sensor array,
`the green beam on the second sensor array, and the blue
`beam on the third sensor array. The outputs of the sen
`sor assembly form a'red/green/blue signal which repre
`sents the portion of the color image on a transparency
`which is aligned with the support assembly aperture.
`The blue, green and red beams are transposed and fo
`cused by the projection assembly. The photoelectric
`sensor arrays, which are typically formed from a matrix
`of photosensitive semiconductor devices, convert the
`intensities of various portions of the red, green, and blue
`beams to form the red/green/blue signal.
`Another known method of ?ltering imaging light
`which is to be impinged upon a three-line CCD unit is
`to apply a ?lter coating directly to each linear CCD
`array. Three-line CCD units which have different color
`?lters deposited directly on the linear CCD arrays are
`known in the art and are commercially available. How
`ever there are several disadvantages which are associ
`ated with such CCD units:
`1) The deposited ?lter material must be compatible
`with the silicon substrate material from which the CCD
`is constructed. There are only a limited number of ?lter
`materials which are suitable for deposit on a CCD sub
`strate. The spectral response bandwidths available from
`such deposited ?lters is limited and may not be suitable
`for some imaging device applications where high color
`?delity is required.
`2) The ef?ciency or transmissibility of ?lters depos
`ited directly onto the CCD sensor arrays is relatively
`low and thus when such coated sensors are used it may
`be necessary to use expensive, highly efficient optics.
`3) The production process for depositing ?lter coat
`ings directly onto CCD arrays is rather expensive. Ad
`ditionally, if a process error occurs during the ?lter
`deposit process the entire silicon substrate must be
`scrapped at considerable expense.
`It is an object of the present invention to provide a
`?lter and sensor assembly which overcomes these prob
`lems in the art.
`SUMMARY OF THE INVENTION
`The present invention is directed to a light sensor
`assembly of the type which is used in a color imaging
`device such as an optical scanner. The light sensor as
`sembly includes a plurality of spatially separated photo
`sensor arrays which each generate light sensing signals
`indicative of the intensity of the light which is impinged
`on the photosensor array. In one embodiment, the pho
`tosensor arrays are linear photosensor arrays which are
`positioned in parallel relationship on a common plane.
`The light sensor assembly also includes a transparent
`plate which is positioned in overlying relationship with
`the plurality of separate photosensor arrays. One sur
`face of the transparent plate has ?lter coatings applied
`to adjacent regions thereof which are aligned with the
`underlying photosensor arrays. A ?lter coating of a
`different spectral range is aligned with each of the dif
`ferent photosensor arrays.
`The light sensor assembly is particularly adapted to
`be positioned at the image plane of an associated color
`
`CROSS REFERENCE TO RELATED
`APPLICATION
`This is a continuation of copending application Ser.
`No. 07/869,273 ?led on Apr. 15, 1992, now abandoned.
`BACKGROUND OF THE INVENTION
`The present invention relates generally to optical
`scanners and, more particularly to color optical scan
`ners and photosensors used therein.
`Optical scanners operate by imaging an object and
`then separating the imaging light into its spectral com
`ponents, typically red, green, and blue. Separate color
`component images are sensed by different optical sensor
`arrays which each generate a signal representative of
`the associated color component image which is sensed.
`These data signals from the different sensors are then
`processed and stored on a suitable medium, e.g. a hard
`disk of a computer or video tape of a camcorder for
`subsequent display and/or manipulation.
`A number of color scanning devices are described in
`US. Pat. No. 4,709,144 for COLOR IMAGER UTI
`LIZING NOVEL TRICHROMATIC BEAMSPLIT
`TER AND PHOTOSENSOR of Vincent issued Nov.
`24, 1987; US. Pat. No. 4,783,696 for COLOR IMAGE
`INPUT APPARATUS WITH VARIOUS ELE
`MENTS HAVING MATCl-IED APERTURES of
`Neumann et al. issued Nov. 8, 1988; US. Pat. No.
`5,019,703 for OPTICAL SCANNER WITH MIRROR
`MOUNTED OCCLUDING APERTURE OR FIL
`35
`TER of Boyd et al. issued May 28, 1991; and US. Pat.
`No. 5,044,727 for BEAM SPLI'ITER/COMBINER
`APPARATUS of Steinle issued Aug. 13, 1991 which
`are each hereby speci?cally incorporated by reference
`for all that is disclosed therein. Scanners typically em
`ploy linear sensor arrays which sense imaging light
`from a scan line portion of an object. A linear sensor
`array comprises a single row of picture elements or
`“pixels” which each generate a signal representative of
`the intensity of the light impinged thereon. A typical
`pixel dimension in a linear sensor array of a color opti
`cal scanner is 0.008 mmX0.008 mm.
`Some optical scanners employ a three-line, CCD
`(charge coupled device) photosensor unit which is used
`to simultaneously sense red, green and blue imaging
`light from the scanned object. One method of ?ltering
`the component light beams which are sensed by a three
`line CCD unit is to pass the imaging light beam through
`multiple re?ective color ?lter coatings applied to glass
`plates located between an imaging lens assembly and
`the three-line CCD unit. Such ?ltering methods are
`used with beamsplitter devices such as described in
`9 detail in the above referenced patents of Vincent, Boyd
`et al. and Steinle.
`U.S. Pat. No. 4,783,696 of Neumann et al. discloses a
`color image input apparatus which includes a support
`assembly, and beam forming assembly, a projection
`assembly, and a sensor assembly. The support assembly
`includes an opaque platen provided with an elongate
`aperture. The beam forming assembly includes a pair of
`front re?ecting mirrors and a ?lter assembly. The ?lter
`assembly includes three ?lter windows, each of which
`includes a transmissive color separation ?lter. Light
`shining through a ?rst ?lter window produces a blue
`
`25
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`50
`
`

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`5,300,767
`4
`3
`the imaging assembly of the scanner (or as the scanner
`scanner. Imaging light from an object passes through
`imaging assembly is moved relative to the object).
`the transparent plate and the ?lter coating associated
`For the purpose of understanding the present inven
`with each photosensor array prior to impinging upon
`tion, it is useful to consider an object 14 which is imaged
`the photosensor ray. The photosensor arrays generate
`to consist of a continuous series of adjacent scan line
`data signals representative of a color component image
`portions extending perpendicular to the scan direction
`of different portions of the object which is being im
`13. FIG. 1-3 illustrates the manner in which three
`aged. These data signals may be manipulated and stored
`spaced apart scan line portions 15, 17, 19 of image 14 are
`in a manner such that a color component image of the
`imaged on image plane II as line images 52, 54, 56 re
`object may be reproduced from the stored data.
`spectively. FIGS. 1 and 3 illustrate that the imaging
`In one preferred embodiment, the ?lter coatings ap
`light reflected from each scan line portion of an object
`plied to the glass plate are dichroic ?lter coatings. Di
`comprises a bundle of light arrays 32, 34, 36 having an
`chroic ?lter coatings are relatively high ef?ciency ?l
`expanding wedge shape con?guration as the light rays
`ters and are available in many different spectral ranges.
`enter the lens assembly 28 and having a contracting
`Thus the present invention offers a broader range of
`wedge shape con?guration as the rays exit the imaging
`spectral-response band widths than are available in
`assembly 28. FIG. 2 shows the center planes 33, 35, 37
`CCD image sensors in which the ?lter coatings are
`of each of these wedge shaped bundles of light rays 32,
`deposited directly upon the CCD’s. The present inven
`34, 36 respectively.
`tion is therefore capable of producing higher ?delity
`A photosensor assembly 40 is shown in cross-section
`color than CCD sensor assemblies having direct deposit
`in FIG. 3. The photosensor assembly 40 may comprise
`?lters. The greater ef?ciency of dichroic coatings
`a generally parallelepiped-shaped member having a
`which may be applied to a glass plate render the present
`front face surface 41 and a back face surface 42. The
`invention capable of being used with less expensive
`front faces has ?rst generally parallelepiped-shaped
`optics than those used with CCD photosensors having
`recess 43 extending inwardly therefrom. A second gen
`direct deposit ?lters. Furthermore, since glass plates are
`erally parallelepiped-shaped recess extends further in
`relatively inexpensive a process error in the ?lter coat
`wardly from the ?rst recess 43. The second recess is
`ing process of the present invention only necessitates
`de?ned by peripheral side walls 45 extending perpen
`the scrapping of a relatively inexpensive glass cover
`dicular to front face surface 41 and a pedestal 49 which
`plate, not an entire CCD substrate.
`projects outwardly from bottom wall 46 and which
`Thus, the present.invention enables the construction
`comprises a pedestal sidewall 47 and a pedestal front
`of a less expensive, more efficient, and higher color
`face surface 48 parallel to front face surface 41. The
`?delity sensing device than that which is available using
`pedestal front face surface 48 is positioned in coplanar
`relationship with image plane II. Parallel linear photo
`current CCD sensor technology.
`sensor arrays 52, 54, 56 which in a preferred embodi
`ment comprise CCD arrays are positioned in spaced
`apart relationship on pedestal front face 48 and thus lie
`in image plane II, FIGS. 2 and 5.
`Each linear photosensor array generates a data signal
`representative of the intensity of light impinged thereon
`which is transmitted via leads $8, 59 to appropriate
`signal processing software and or storage media. In the
`optical scanning assembly illustrated in FIG. 1, the
`scanned data from two of the three sensors is buffered
`and stored in an appropriate number of lines in random
`access memory of an associated computer (not shown).
`The data is then shifted as a function of scan speed such
`that data representative of the three color component
`images of each scan line portion of the object are stored
`together. The stored data may be used to reproduce a
`color image of the object which is scanned. Typical
`display devices are color CRT’s and color printers (not
`shown).
`As illustrated in FIGS. 1, 3, and 4 a transparent plate
`70 is mounted in the second recess 44 of the photosensor
`assembly 40. (The transparent plate is not shown in
`FIG. 2 or in FIG. 3.) The transparent plate may be a
`generally parallelepiped-shaped plate having a ?rst
`planer surface portion 72 lying in a plane AA parallel to
`image plane II and having a second planer surface por
`tion 74 lying in a plane BB parallel to planes AA and II.
`The transparent plate 70 may have a slight recess (not
`shown) about its periphery of a predetermined height to
`enable it to be placed into recess 44 in the photosensor
`assembly at a predetermined distance from the front
`face 48 of pedestal 49.
`As best illustrated in FIGS. 3 and 4, adjacent surface
`regions of transparent plate 70 aligned with photosen
`sors 52, 54, 56 respectively are coated with different
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`FIG. 1 illustrates an optical scanning device 10 for
`generating a data signal 12 representative of an object
`14 which is being scanned. The optical scanning device
`comprises a light source assembly 16 such as ?uorescent
`bulbs 18, 20 which are adapted to illuminate an object
`14 and which are shielded from scanner optics as by
`light blocking shields 22, 22. An imaging assembly 28
`which may comprise an imaging lens assembly of the
`type described in U.S. Pat. No. 5,044,727 incorporated
`by reference above, is provided for imaging light re
`?ected from the scan object 14. The imaging assembly
`28 images the light (i.e. projects an image of the object)
`onto an image plane II. As explained in detail in the
`above cited patents a scanner operates by sensing a
`continuing series of scan line portions of an object as the
`object is moved in a scan path direction 13 relative to
`
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`20
`
`BRIEF DESCRIPTION OF THE DRAWING
`FIG. 1 is a schematic, cross-sectional side elevation
`view of an optical imaging device.
`FIG. 2 is a schematic perspective view showing cer
`tain features of the imaging device of FIG. 1.
`FIG. 3 is a detail side elevation view of a portion of
`40
`a lens assembly and a portion of a photosensor assembly
`of the imaging device of FIG. 1.
`FIG. 4 is a top plan view of the photosensor assembly
`shown in FIG. 3 with a transparent plate in place.
`FIG. 5 is a top plan view of the photosensor assembly
`shown in FIG. 3 with a transparent plate removed.
`FIG. 6 is a detail cross-sectional side elevation view
`of a ?lter coated glass plate adhered to a linear photo
`sensor array with optical adhesive.
`
`45
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`35
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`5,300,767
`6
`5
`a) a plurality of parallel, spatially separated, linear
`?lter coatings 82, 84, 86. The coatings are extremely
`photosensor means for generating a plurality of
`thin, typically on the order of 2.5 pm. In one preferred
`light sensing signals indicative of the intensity of
`embodiment, the ?rst ?lter coating 82 is a dichroic
`light in predetermined spectral regions impinged
`material adapted to transmit red light, the second ?lter
`thereon;
`coating 84 is a dichroic material adapted to transmit
`b) transparent plate means for transmitting light to
`green light, and the third ?lter coating 86 is a dichroic
`said photosensor means positioned in adjacent
`material adapted to transmit blue light. The coatings are
`overlying relationship with said photosensor
`preferably placed on the ?rst planer surface portion 72
`means;
`located proximal pedestal surface 48 rather than the
`c) a plurality of ?lter coating means disposed on a
`planar surface portion 74 located distal the pedestal so
`surface portion of said transparent plate means in
`as to maintain the ?lter coatings within a generally dust
`alignment with said plurality of photosensor means
`free enclosure.
`for ?lteringly transmitting said light in each of said
`It will be appreciated from FIG. 3 that the different
`predetermined different spectral regions to said
`wedge shaped bundles of light rays 32, 34, 36 associated
`photosensor means; whereby each of said linear
`with scan images 52, 54, 56 overlap with one another in
`photosensor means receives light from a different
`the portions thereof extending from the imaging assem
`one of said predetermined spectral regions;
`bly 28 until they reach plane MM. At plane MM the
`said plurality of photosensor means being arranged in
`bundles of light rays become separated. As illustrated in
`a ?rst plane, said plurality of ?lter coating means
`FIG. 3, MM is position at a distance “a” from image
`being arranged in a second plane parallel to said
`plane II. The dimension “a" is a function of linear sensor
`?rst plane.
`spacing “d” (distance between photosensor longitudinal
`2. The invention of claim 1, said transparent plate
`centerlines, FIG. 5), sensor pixel width “p” (measured
`means comprising a ?rst surface portion positioned
`perpendicular to the longitudinal axis of the associated
`proximal said photosensor means and a second surface
`linear sensor array, FIG. 5), and the effective F-number
`portion positioned distal said photosensor means said
`25
`“i” of the lens assembly (effective F-number is an opti
`plurality of ?lter coating means being disposed on said
`cal parameter well known in the art). The distance “a”
`?rst surface of said transparent plate means.
`may be expressed by the mathematical formula
`3. The invention of claim 1, said plurality of photo
`a=[(d—p)/2]/tan[sin-1(§i)]. It is critical that the dis
`sensor means and said plurality of ?lter coating means
`tance “it” between the surface AA supporting the ?lter
`being disposed in a common enclosure.
`coatings and image plane II is no greater than “a” to
`4. The invention of claim 1, said ?lter coating means
`prevent ?ltering of each imaging light beam by more
`comprising dichroic coatings.
`than one ?lter. The ?lter coatings may alternatively be
`5. The invention of claim 1, said light sensor assembly
`comprising a subassembly of an optical imaging device.
`placed upon surface BB of glass plate 70 so long as
`6. The invention of claim 1 said ?lter coating means
`surface BB is positioned no more than dimension “a”
`being in optical contact with associated photosensor
`from image plane II.
`In one preferred embodiment of the invention the
`means.
`7. The invention of claim 1, said transparent plate
`photosensor unit comprises a CCD unit with linear
`means comprising a ?rst surface portion positioned
`photosensor arrays which are each 29.2 mm long and
`proximal said linear photosensor arrays and a second
`which are spaced apart from center line to center line at
`surface portion positioned distal said photosensor ar
`a distance “d” of 0.2 mm. The width “p” of the pixels in
`rays, said plurality of ?lter coating means being dis
`each linear photosensor array is 0.008 mm. The lens
`posed on said ?rst surface of said transparent plate
`assembly has an effective F-number “t” of 4.5. The
`means, said plurality of photosensor means being pro
`distance 9‘it” between image plane 11 and plate surface
`vided on a common ?at surface portion of a photosen
`72 to which the ?lter coatings are applied is less that “a”
`sor unit, said plurality of linear photosensor arrays and
`which equals 859 pm. In a most preferred embodiment
`said plurality of ?lter coating means being disposed in a
`the ?lter coatings have an optical adhesive applied
`common enclosure de?ned by at least a portion of said
`thereto which comes into direct contact with the sur
`transparent plate means and at least a portion of said
`face of the associated CCD arrays such that the ?lters
`common flat surface portion of said photosensor unit,
`are in optical contact with the associated CCD arrays.
`said ?lter coating means comprising dichroic coatings,
`A typical optical adhesive which may be used for this
`and said plurality of linear photosensor means compris
`purpose is commercially available under the product
`ing CCD arrays.
`designation of Norland Optical Adhesive 61, from Nor
`8. A method of generating a data signal representa
`land Products Inc., having a business located in New
`tive of a color image of an object comprising the steps
`Brunswick, N.J., 08902. The optical adhesive coating
`55
`Of:
`would typically have a thickness of about 10 pm. A
`a) adhering a plurality of different ?lter coatings to
`schematic elevation view showing a ?lter coating 82
`different regions of a ?rst planar surface portion of
`applied to glass plate surface 72 and adhered to CCD
`a transparent plate;
`array 52 by optical adhesive 90 is shown in FIG. 6.
`b) positioning the transparent plate over a plurality of
`While illustrative and presently preferred embodi
`different linear photosensor arrays such that a dif
`ments of the invention have been described in detail
`ferent ?lter coating is aligned with each of the
`herein, it is to be understood that the inventive concepts
`different photosensor arrays;
`may be otherwise variously embodied and employed
`c) passing focused imaging light from the object
`and that the appended claims are intended to be con
`through the transparent plate and ?lter coatings
`strued to include such variations except insofar as lim
`disposed thereon to form a single two-dimensional
`ited by the prior art.
`image encompassing said plurality of linear photo
`What is claimed is:
`sensor arrays;
`1. A light sensor assembly comprising:
`
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`
`I
`I
`d) generating a data signal indicative of the intensity
`of light impinged upon each of the photosensor
`
`5,300,767
`15. The invention of claim 14, said imaging means
`having an effective F-number of “i”, said plurality of
`photosensor means being of an equal width “p” and
`arranged in a ?rst plane at equal spacing intervals of
`“d”, said plurality of ?lter coating means being ar
`ranged in a second plane parallel to said ?rst plane, said
`?rst plane being spaced from said second plane by a
`distance of no more than a distance “a”, where
`
`10
`
`arrays.
`'
`9. The invention of claim 8 wherein the step of adher
`ing ?lter coatings comprises adhering dichroic ?lter
`coatings.
`10. The invention of claim 9 wherein the step of posi
`tioning the plate over the linear photosensor arrays
`comprises positioning the ?rst surface portion of the
`plate proximate the photosensors.
`11. The invention of claim 8 wherein the step of posi
`tioning the plate over the photosensor arrays comprises
`forming an enclosure which contains the ?lter coatings
`and the photosensor arrays.
`12. The invention of claim 8 comprising the further
`step of placing each ?lter coating in optical contact
`with the aligned linear photosensor array.
`13. The invention of claim 8 wherein the linear photo
`sensor arrays comprise a common pixel width “p" and
`are separated by equal spacing intervals “d” and
`wherein the linear photosensor arrays comprise a por
`tion of an optical scanning apparatus having an imaging
`assembly with an effective F-number of “f” and
`wherein the step of positioning the transparent plate
`over the linear photosensor arrays comprises position
`ing the ?lter coatings at a distance no greater than a
`distance “a” from the photosensor arrays where
`a=[d—P)/2]/t1w[§i?'‘(ml
`14. An optical scanning device for generating a data
`signal representative of an object which is scanned com
`prising:
`a) light source means for illuminating the object;
`b) imaging means for projecting imaging light from
`the object onto an image plane;
`c) a plurality of parallel linear photosensor means
`positioned at said image plane for generating a
`plurality of light sensing signals indicative of the
`intensity of imaging light in predetermined spectral
`regions impinged thereon;
`d) transparent plate means for transmitting imaging
`light to said plurality of photosensor means posi
`tioned in overlying relationship with said photo
`sensor means;
`e) a plurality of parallel, elongated ?lter coating
`45
`means disposed on a surface portion of said trans
`parent plate means in respective parallel alignment
`with said plurality of photosensor means for ?lter
`ingly transmitting said imaging light in predeter
`mined different spectral regions to said photosen
`sor means whereby each photosensor means re
`ceives light from a different one of said predeter
`mined spectral regions.
`
`.
`a=[<l—l>)/2l/"mlsi?‘‘(i?l-
`16. The invention of claim 14, said transparent plate
`means comprising a ?rst surface portion positioned
`proximal said photosensor means and a second surface
`portion positioned distal said photosensor means said
`plurality of ?lter coating means being disposed on said
`?rst surface of said transparent plate means.
`17. The invention of claim 14, said plurality of photo
`sensor means and said plurality of ?lter coating means
`being disposed in a common enclosure.
`18. The invention of claim 14, said ?lter coating
`means comprise dichroic coatings.
`19. The invention of claim 14, said plurality of linear
`photosensor means comprise CCD arrays.
`20. The invention of claim 14 said linear photosensor
`means being in optical contact with associated ones of
`said ?lter coating means.
`21. The invention of claim 20 linear photosensor
`means being adhered to associated ones of said ?lter
`layer means by optical adhesive.
`22. The invention of claim 14, said transparent plate
`means comprising a ?rst surface portion positioned
`proximal said photosensor means and a second surface
`portion positioned distal said photosensor means, said
`plurality of ?lter coating means being disposed on said
`?rst surface of said transparent plate means, said plural
`ity of photosensor means being provided on a common
`?at surface portion of a photosensor unit, said plurality
`of photosensor means and said plurality of ?lter coating
`means being disposed in a common enclosure de?ned
`by at least a portion of said transparent plate means and
`at least a portion of said common ?at surface portion of
`said photosensor unit, said imaging means having an
`effective F-number of “f”, said plurality of photosensor
`means being of an equal width of “p’fand arranged in a
`?rst plane at equal spacing intervals of “d”, said plural
`ity of ?lter coating means being arranged in a second
`plane parallel to said ?rst plane, said ?rst plane being
`spaced from said second plane by a distance of no more
`than a distance “a”, where a=[d—p)/2]/tan[sin- l(m1,
`said ?lter coating means comprise dichroic coatings,
`and said plurality of photosensor means comprise CCD
`arrays.
`
`25
`
`35
`
`40
`
`55
`
`65