United States Patent (19)
`Nagano
`
`Patent Number:
`11
`45) Date of Patent:
`
`4,642,679
`Feb. 10, 1987
`
`54 COLOR IMAGE READINGAPPARATUS
`75) Inventor: Fumikazu Nagano, Yamatokoriyama,
`Japan
`73) Assignee: Sharp Kabushiki Kaisha, Osaka,
`Japan
`21 Appl. No.: 744,474
`22 Filed:
`Jun. 13, 1985
`(30)
`Foreign Application Priority Data
`Jun. 15, 1984 JP
`Japan ................................ 59-1242O2
`Jun. 15, 1984 JP
`Japan ................................ 59-124203
`Aug. 2, 1984 JP
`Japan ................................ 59-163713
`Aug. 22, 1984 (JP)
`Japan ................................ 59-175353
`Nov. 30, 1984, JP
`Japan ................................ 59-254580
`51) Int. Cl. ............................................... H04N 1/46
`52 U.S. C. .......
`. 358/75; 358/80
`58) Field of Search .................................... 358/75, 80
`(56)
`References Cited
`U.S. PATENT DOCUMENTS
`4,318,122 3/1982 White ........................... 358/75 X
`
`FOREIGN PATENT DOCUMENTS
`30215 3/1980 Japan ..................................... 358/75
`Primary Examiner-Randall L. Green
`Attorney, Agent, or Firm-Birch, Stewart, Kolasch and
`Birch
`ABSTRACT
`57
`A color image reading device for reading an original by
`an optical scanning device which optically scans across
`said original line-by-line is disclosed. The color image
`reading device includes a green fluorescent lamp for
`generating a green light with an afterglow characteris
`tics, a red fluorescent lamp for generating a red light
`with no afterglow characteristics, and a blue fluorescent.
`lamp for generating a blue light with no afterglow char
`acteristics. The green, red and blue fluorescent lamps
`are actuated in a predetermined time sequence. A CCD
`is provided for detecting an image under green during
`the afterglow, under red light and under blue light.
`
`13 Claims, 27 Drawing Figures
`
`
`
`
`Ex.1038 / Page 1 of 20Ex.1038 / Page 1 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 1 of 11
`
`4,642,679
`
`
`
`
`Ex.1038 / Page 2 of 20Ex.1038 / Page 2 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`A/7. 27
`
`M M2 M3 M4
`
`Sheet 2 of 11
`
`4,642,679
`
`4OO 5OO
`
`7OO
`6OO
`R - LIGHT
`
`800
`
`WAVELENGTH
`(nm)
`
`Afg. 2A
`
`M3
`
`g
`E
`s O
`
`
`
`
`
`A/g. 2c
`a
`C S.
`
`O
`all
`
`Afg. 5a
`
`4OO
`
`5OO
`
`7OO
`SOO
`G - LIGHT
`
`M2
`M -7 M3 M4
`/
`
`4OO
`
`5OO
`
`7OO
`6OO
`- GHT
`B -
`
`WAVELENGTH
`(nm)
`
`WAVELENGTH
`(nm)
`
`e
`
`is
`
`- L-A-
`
`Afg. 3 b
`
`4OO
`
`SOO
`
`700
`6OO
`We FILTER
`
`wavingth
`nnn)
`
`2 in
`is is
`
`Afg. 3 c.
`
`or
`
`4OO
`
`SOO
`
`7OO
`6OO
`R - FILTER
`
`WAVEN GTH
`
`u
`2 on
`
`g ---
`14oo
`soo soo
`too
`WAVELENGTH
`B - FILTER
`
`1.
`
`
`Ex.1038 / Page 3 of 20Ex.1038 / Page 3 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 3 of 11
`
`4,642,679
`
`Afg. 4 a
`
`Afg. 4b
`
`Fig. 4c
`
`4OO
`
`WAVELENGTH
`7OO
`6OO
`5OO
`(nm)
`R - LIGHT (FILTERED)
`
`4OO
`
`WAVELENGTH
`7OO
`6OO
`5OO
`(nm)
`G - LIGHT (AFTERGLOW)
`
`WAVELENGTH
`7OO
`6OO
`. 5OO
`(nm)
`B - LIGHT (FILTERED)
`Afg. 6
`
`Af f g 5
`
`F
`
`P
`
`2
`
`to
`
`WE2 WF
`
`Af g 7
`
`4 OO
`
`5OO
`
`6OO
`
`7OO
`
`WAVELENGTH
`(nm)
`
`
`Ex.1038 / Page 4 of 20Ex.1038 / Page 4 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 4 of 11
`
`4,642,679
`
`
`
`CLOCKFUSE
`GP
`CLOCKFULSE
`d2
`
`CPU
`
`
`Ex.1038 / Page 5 of 20Ex.1038 / Page 5 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 5 of 11
`
`4,642,679
`
`Afg. / O
`
`dT —l ---
`to
`be
`R
`CCD
`OUTPUT
`(Vd)
`
`N4n-i N+n
`
`2
`
`3
`
`Ll l
`
`4 5
`
`l l l
`
`l
`
`N-3 N-2 N -
`
`l
`
`l
`
`l
`
`N N +
`
`l JLL
`L
`
`Vd Vd2 Vds V, Vds
`SAMPLNG
`l
`l l
`l
`l L.
`SIGNA
`* (v) W4%
`
`VodN-Vod N
`
`Fig. 8b
`
`... O
`
`O.5
`
`R
`
`4oo 5oo soo 7oo ( nm)
`
`
`Ex.1038 / Page 6 of 20Ex.1038 / Page 6 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 6 of 11
`
`4,642,679
`
`
`
`|-——— 310 Ao ? —>// ± 6 /--/
`
`O A
`
`T1-19)
`
`T-38
`
`T1-JE
`
`
`Ex.1038 / Page 7 of 20Ex.1038 / Page 7 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 7 of 11
`
`4,642,679
`
`
`
`(N
`N
`
`Q
`
`t
`
`He
`
`o
`
`te. >
`
`n
`
`()
`(f)
`
`?o
`of
`
`NN
`
`s
`-
`-
`l
`
`a
`l
`1.
`
`o
`
`9
`ev
`
`in
`s
`
`a
`CD
`
`as
`
`in
`
`GN
`
`5
`
`
`Ex.1038 / Page 8 of 20Ex.1038 / Page 8 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 8 of 11
`
`4,642,679
`
`A / 7. /3
`2 ... or + T -
`BM-1 GM
`Gun R'M Run B'M Bu G'M:
`
`d
`
`Vo
`
`a
`
`.
`
`E
`
`are
`
`I
`
`- -
`
`- RIDAC
`Vo
`
`Tx
`Ts. HGH
`
`B
`
`F
`
`J
`
`Ts LOW
`S. s. S'
`S2 S2' T 1 -
`
`
`Ex.1038 / Page 9 of 20Ex.1038 / Page 9 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 9 of 11
`
`4,642,679
`
`
`
`
`Ex.1038 / Page 10 of 20Ex.1038 / Page 10 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 10 of 11 4,642,679
`
`
`
`
`
`|||||||||||||||||||||||||||||||||||||||||||||||| za'la|-||||||||||||||||||-|||||||||||||||||– zaaºtºa
`
`
`Ex.1038 / Page 11 of 20Ex.1038 / Page 11 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`U.S. Patent Feb. 10, 1987
`
`Sheet 11 of 11 4,642,679
`
`Afg. 2 O
`
`|
`
`|
`
`|
`
`| -
`c) T - |
`l
`RFL --
`R-LAMP --V\-/-
`GFL -- l
`l
`l
`G - LAMP --/\ /
`/ -
`BFL
`- - - -
`B - LAMP -
`/
`/ -
`Vd
`-i
`ill-ir-ir-ir-ir
`
`
`Ex.1038 / Page 12 of 20Ex.1038 / Page 12 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`1.
`
`COLOR IMAGE READINGAPPARATUS
`
`10
`
`15
`
`20
`
`BACKGROUND OF THE INVENTION
`1. Field of the Invention
`The present invention relates to a color image read
`ing device for use in a color facsimile machine, color
`scanner, or the like, wherein an original color image is
`separated into different color data which are detected
`using a CCD sensor.
`2. Description of the Prior Art
`The prior art color image reading devices can be
`divided typically into two types, which are:
`(1) a type using a white lamp as a light source, in
`which three different filters red, green and blue, (R, G,
`B) mechanically replace one after the other sequentially
`in front of a CCD array to separate the color image into
`different colors; and
`(2) a type using a white lamp as a light source, in
`which three CCD arrays provided with filters R, G, B,
`respectively, are provided to separate the color image
`into different colors.
`According to the first type, it is very difficult to
`change the filters rapidly. According to the second
`type, three different colors are detected at different
`places where the three CCD arrays, are positioned.
`Therefore, the exact matching of the three color images
`is very difficult.
`To solve the above problem, another type of color
`image reading device has been proposed which employs
`three fluorescent lamps for emitting three color lights,
`red light, green light and blue light, which are turned on
`sequentially one at a time, and one CCD array for re
`ceiving red light image, green light image and blue light
`image at different times.
`However, a fluorescent lamp generally has four
`strong line spectrums at about 405 nm, 436 nm, 546 nm,
`and 587 nm, due to mercury contained therein. These
`line spectrums must be deleted, or otherwise the color
`separation can not be done properly with a desired
`result. Of the four line spectrums, the 405 nm and 436
`nm line spectrums can be deleted easily using a suitable
`filter. However, the 546 nm and 587 nm line spectrums
`are located in a spectrum region of the green fluores
`cent lamp and, therefore, these line spectrums can not
`45
`be deleted by the use of filters. Moreover, the presence
`of 546 mm and 587 nm line spectrums at places within
`the spectrum region of the green fluorescent lamp, but
`off from the peak point thereof will adversely affect the
`separation of green data from CCD output.
`SUMMARY OF THE INVENTION
`The present invention has been developed with a
`view to substantially solving the above described disad
`vantages and has for its essential object to provide an
`55
`improved color image reading device.
`It is also an essential object of the present invention to
`provide a color image reading device which can elimi
`nate noise signals caused by the afterglow of a green
`lamp that exists during the red light exposure and blue
`light exposure.
`In accomplishing these and other objects, a color
`image reading device according to the present inven
`tion comprises a green fluorescent lamp for generating
`a green light with an afterglow characteristics, a red
`65
`fluorescent lamp for generating a red light with no
`afterglow characteristics, and a blue fluorescent lamp
`for generating a blue light with no afterglow character
`
`4,642,679
`2
`istics. The green, red and blue fluorescent lamps are
`actuated in a predetermined time sequence. A CCD is
`provided for detecting an image undergreen light dur
`ing the afterglow, under red light and under blue light,
`at different time sequences.
`BRIEF DESCRIPTION OF THE DRAWINGS
`These and other objects and features of the present
`invention will become apparent from the following
`description taken in conjunction with a preferred em
`bodiment thereof with reference to the accompanying
`drawings, throughout which like parts are designated
`by like reference numerals, and in which:
`FIG. 1 is a block diagram of a color image reading
`device according to a preferred embodiment of the
`present invention;
`FIGS. 2a, 2b and 2c are graphs showing relative
`spectral power distributions of lights from a red fluores
`cent lamp, a green fluorescent lamp and a blue fluores
`cent lamp, respectively;
`FIGS. 3a, 3b and 3c are graphs showing characteris
`tics of various filters used for cutting line spectrums of
`mercury;
`FIGS. 4a, 4b and 4c are graphs showing relative
`spectral power distributions of lights from a red-lamp, a
`green-lamp and a blue lamp, respectively, through fil
`ters;
`FIG. 5 is a side elevational view of a combined filter
`of red-filter and blue filter;
`FIG. 6 is a cross sectional view of a white filter;
`FIG. 7 is a graph showing a sensitivity characteristics
`of a CCD used in the preferred embodiment;
`FIG. 8a is a diagrammatic view showing an optical
`arrangement of the three fluorescent lamps and the
`parts associated therewith;
`FIG. 8b is a graph showing a relative spectral power
`distributions of lights from red, green and blue fluores
`cent lamps;
`FIG. 9 is a diagrammatic view showing a basic ar
`rangement of the CCD and electric circuit parts for
`processing the signal produced from the CCD;
`FIG. 10 is a chart showing an operation of the CCD
`in a timed relationship;
`FIG. 11 is a chart showing a general operation for
`carrying out the color separation in a timed relation
`ship, according to the present invention;
`FIG. 12 is a chart showing an operation for storing
`green databased on the afterglow of the green fluores
`cent lamp at different times;
`FIG. 13 is a chart showing an operation for storing
`reference data for each of green, red and blue lights;
`FIG. 14 is a chart showing an operation for reading a
`color document;
`FIG. 15 is a circuit diagram showing a lamp drive
`circuit for effecting the preheating of each fluorescent
`lamp;
`FIG. 16 is a graph showing waveforms for effecting
`the preheat according to the present invention;
`FIG. 17 is a graph showing a distribution of light
`intensity of a lamp at times T1 and T2 indicated in FIG.
`16;
`FIG. 18 is a graph showing waveforms for effecting
`the preheat according to the prior art;
`FIG. 19 is a graph showing a distribution of light
`intensity of a lamp at times T1 and T2 indicated in FIG.
`18; and
`
`25
`
`30
`
`35
`
`50
`
`
`Ex.1038 / Page 13 of 20Ex.1038 / Page 13 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`15
`
`20
`
`O
`
`4,642,679
`3
`4
`FIG. 20 is a graph showing the operation of three
`CCD array, the R-filter is positioned in front of the
`R-lamp and B-filter is positioned in front of B-lamp.
`fluorescent lamps which are actuated at the same time at
`the beginning of each cycle of operation to ensure the
`Accordingly, the red light emitted from the R-lamp
`uniform emission of light through out the operation.
`passes through the R-filter and W-filter. Thus the light
`from the R-lamp will be so filtered as to have a relative
`DESCRIPTION OF THE PREFERRED
`spectral power distribution shown in FIG. 4a, wherein
`EMBODIMENTS
`line spectrums M1-M4 are eliminated.
`Similarly, the blue light emitted from the B-lamp
`Before the description proceeds to the preferred em
`passes through the B-filter and W-filter. Thus the light
`bodiment, fluorescent lamps and filters used in the pres
`from the B-lamp will be so filtered as to have a relative
`ent invention will be described.
`spectral power distribution shown in FIG. 4c, wherein
`Referring to FIGS. 2a to 2c, graphs illustrated therein
`line spectrums M1, M3 and M4 are eliminated.
`show relative spectral power distributions of lights
`Furthermore, the green light emitted from the G
`from red fluorescent lamp (R-lamp), green fluorescent
`lamp passes through only the W-filter. Also, the green
`lamp (G-lamp) and blue fluorescent lamp (B-lamp),
`light used in the present invention is obtained during the
`respectively. As indicated in each graph, the mercury
`afterglow. Thus, the green lights detected by the CCD
`line spectrums M1, M2, M3 and M4 are present at the
`will have a relative spectral power distribution shown
`frequencies approximately 405 nm, 436 nm, 546 nm and
`in FIG. 4b, wherein line spectrums M1-M4 are elimi
`587 nm, respectively, in every fluorescent lamp.
`nated.
`As shown in FIG. 2a, the R-lamp has a relatively
`Referring to FIG. 5, a side elevational view of a
`wide spectrum region, but the region used for detecting
`combined filter of R-filter and B-filter is shown. Since it
`red data is only a part in the long wavelength region.
`is difficult to make the R-filter and B-filter on a single
`Accordingly, by the use of suitable filters, it is possible
`elongated sheet at the same time, the R- and B-filters are
`to eliminate all of the unwanted line spectrums M1-M4.
`made separately, and then are joined together by a suit
`As shown in FIG. 2c, the B-lamp also has four line
`able bonding agent, or the like.
`25
`spectrums M1-M4. Of these four line spectrums, M1,
`Referring to FIG. 6, a cross sectional view of the
`M3 and M4 can be eliminated by the use of suitable
`W-filter is shown, which comprises a glass filter WF1
`filters. Although the line spectrum M2 can not be elimi
`and an interference filter WF2 made of a thin film de
`nated, the presence of line spectrum M2 will not ad
`posited on glass filter WF1. Glass filter WF1 cuts off
`versely affect the separation of blue data, because the
`the short wavelength region and interference filter
`30
`line spectrum M2 is situated close to the peak of the
`WF2 cuts off the long wavelength region.
`spectrum region.
`FIG. 7 shows a relative sensitivity of a CCD array
`As shown in FIG. 2b, of the four line spectrums
`with respect to different wavelengths.
`M1-M4 in the spectrum region of G-lamp, M1 and M2
`Referring to FIG. 8a, an optical arrangement of the
`can be eliminated by the use of suitable filters. How
`color image reading device according to the present
`35
`ever, line spectrums M3 and M4 can not be eliminated
`invention is shown. Red fluorescent lamp (R-lamp) 1,
`with the filters.
`green fluorescent lamp (G-lamp) 2 and blue fluorescent
`To eliminate all of the line spectrums M1-M4, ac
`lamp (B-lamp) 3 are fixedly provided in a casing 4. Red
`cording to the present invention, a green fluorescent
`filter 5 is positioned in front of R-lamp 1, and blue filter
`:... lamp having an afterglow characteristics is employed.
`6 is positioned in front of B-lamp 3. Casing 4 has a trans
`. . . Accordingly, the separation of green data is effected
`parent glass plate 41 provided at the upper end of casing
`such that the CCD starts charging the green data under
`4, when viewed in FIG. 8a. An elongated slit 40 is
`the afterglow of the green fluorescent lamp, that is
`provided at the bottom of casing 4 for the light passage.
`immediately after the cut off of power to the green
`Provided immediately above casing 4 is a movable plat
`fluorescent lamp. Since there is no line spectrum con
`form 7 for placing an original 8. A white zone 70 is
`45
`tained in the afterglow, the separation of green data
`provided at the leading end of platform 7. A ribbon of
`under the afterglow can be carried out without any
`light emitted from each of lamps 1, 2 and 3 sequentially
`influence by the line spectrum.
`one after the other is directed and reflects on original 8
`However, the use of the afterglow gives rise to such
`at a reading line RL so as to read one particular line on
`a problem that the afterglow still exists during the sepa
`the original. The light reflected on original 8 is transmit
`50
`rations of the red data and blue data which are carried
`ted through slit 40, and suitable reflection mirror 9,
`out sequentially after the separation of the green data.
`W-filter 10, and a lens arrangement 11 to CCD array 12
`The afterglow which exists during the separations of
`along optical axes X1 and X2.
`red data and blue data will result in undesirable noise
`When the reading of one line on the original com
`signals in the separated red data and blue data. The
`pletes, that is when one cycle operation completes, a
`55
`elimination of such noise signals is done by the color
`pulse motor 210 (FIG. 1) is actuated to move platform
`image reading device of the present invention, as will be
`7 in a SCAN direction, as indicated by an arrow, by a
`described in detail later.
`predetermined pitch so as to read the next line on the
`Referring to FIGS.3a to 3c, graphs illustrated therein
`original. In this manner, the original is read out line by
`show relative permeability of three different filters for
`line. When the reading of one original completes, plat
`eliminating the unwanted line spectrums mentioned
`form 7 is moved in a RETURN direction, as indicated
`above. The graph of FIG. 3a represents a white filter
`by an arrow, so as to locate white zone 70 at the position
`(W-filter) which permits the lights in the visible region
`where the ribbon of lights is directed. By the use of
`to pass therethrough. The graph of FIG. 3b represents
`lights reflected from white zone 70, white balance is
`a red filter (R-filter) which permits the red lights to pass
`carried out.
`65
`therethrough, and the graph of FIG. 3c represents a
`As indicated in FIG. 8b, the peaks of relative spectral
`blue filter (B-filter) which permits the blue lights to pass
`power distributions of lights from red, green and blue
`therethrough. The W-filter is positioned in front of the
`fluorescent lamps are different such that the peak of the
`
`60
`
`
`Ex.1038 / Page 14 of 20Ex.1038 / Page 14 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`10
`
`15
`
`25
`
`30
`
`Lamp
`R-lamp
`G-lamp
`G-lamp
`
`Distance to RL
`30 mm
`35 mm
`40 mm
`
`4,642,679
`5
`6
`B-lamp is the highest, that of the R-lamp is the lowest
`the separation of green data. The detail of the subtrac
`and that of the G-lamp is in the middle. Since it is pref
`tion will be described later.
`erable to make the light intensity at reading line RL the
`Then, a voltage signal Vo' produced from subtraction
`same among three different colors, and since it is prefer
`circuit 125 is applied to a shading corrector 126 in
`able to position the three lamps at places where the 5
`which the white balance correction (shading correc
`emitted lights can be utilized with a high efficiency,
`tion) is carried out. The corrected signal produced from
`three lamps 1, 2 and 3 are positioned in a manner de
`corrector 126 is applied to a CPU (not shown) and also
`scribed below.
`to a controller 127.
`The lamp having the weakest light emission power,
`The image reading as carried out by CCD array 12 is
`i.e., the R-lamp, is positioned on one side of optical axis
`shown in FIG. 10. Since the operation of the CCD is
`X1, and the lamps having the first and second strongest
`known, a further description therefor is omitted for the
`light emission power, i.e., the B-lamp and G-lamp are
`sake of brevity.
`positioned on the other side of optical axis X1.
`Referring to FIG. 1, a color image reading device
`According to the preferred embodiment, the R-lamp,
`according to a preferred embodiment of the present
`which is positioned on one side of optical axis X1, is
`invention is shown.
`located at such a position that the red light emitted
`Controller 127 produces signals RFL, GFL and BFL
`therefrom impinges on reading line RL with the most
`to a lamp drive circuit 205 so as to lit G-lamp 2, R-lamp
`1 and B-lamp 3 sequentially. A detail of lamp drive
`appropriate incident angle 01 with the minimum avail
`able distance spaced from reading line RL. Also, the
`circuit 205 will be described later in connection with
`B-lamp and G-lamp are positioned such that the inci
`FIGS. 15.-19.
`20
`dent angle 02 of blue light is greater than the incident
`As indicated in FIG. 11, G-lamp 2 lights in response
`angle 03 of green light.
`to the signal GFL, but it continues to emit light, even
`Table 1 given below shows an example for position
`after the signal GFL is gone, by the effect of afterglow.
`ing R-lamp, G-lamp and B-lamp.
`As shown in FIG. 11, the green light emitted during the
`presence of the signal GFL is indicated at a region Sa,
`TABLE 1.
`while the green light caused by the afterglow is indi
`Incident Angle
`cated at regions Sb, Sc, Se, Sg and Si, which are so
`divided in accordance with various periods for effecting
`26-30
`16-20
`different operations in the color image reading device.
`46-50
`In the region Sa, the green light is unstable and contains
`line spectrums M3 and M4, but in the other regions of
`the afterglow, the green light is stable with no line
`spectrums.
`R-lamp 1 emits red light in response to the signal
`RFL, and it stops the light emission when the signal
`RFL disappears. The red light emitted during the pres
`ence of the signal RFL is indicated at regions Sd and Sf,
`in which the region Sd is an unstable region and the
`region Sf is a stable region.
`Similarly, B-lamp 1 emits blue light in response to the
`signal BFL, and it stops the light emission when the
`signal BFL disappears. The blue light emitted during
`the presence of the signal BFL is indicated at regions Sh
`and Sj, in which the region Shis an unstable region and
`the region Sj is a stable region.
`Referring to FIG. 1, a voltage signal Vd produced
`from CCD array 12 is applied to sample/hold circuit
`124 which then produces a voltage signal Vo. The volt
`age signal Vo is applied to subtraction circuit 125 which
`comprises a register R, buffer 202, D/A converter 223,
`multiplier 222, Sb memory 220, Se memory 221a and Si
`memory 221b.
`A junction J1 between register R and buffer 202 is
`connected to D/A converter 223. When D/A con
`verter is actuated, a current DAC, which is dependent
`on a signal obtained from multiplier 222, flows out from
`junction J1 to ground. Accordingly a voltage Vo' at
`Junction J1 can be given as follows.
`
`60
`
`Coupled to multiplier 222 is Sb memory 220 defined by
`N-bit register which memorizes green data of each line
`image in the form of N picture elements obtained when
`the original is exposed by the afterglow of the region Sb
`(FIG. 11) of the G-lamp when each line reading is ef
`fected, i.e., in each cycle of operation. At the end of
`each cycle, Sb memory 220 is reset. Also coupled to
`
`
`Ex.1038 / Page 15 of 20Ex.1038 / Page 15 of 20
`
`TESLA, INC.TESLA, INC.
`
`35
`
`50
`
`When the above arrangement of R-, G- and B-lamps
`is employed, the light intensity of the red, green and
`blue lights at reading line RL will be substantially the
`same as each other.
`Referring again to FIG. 8a, casing 4, which contains
`the fluorescent lamps may be so positioned on the other
`side of platform 7, such as shown at 4. In this case, the
`transparent glass plate 41 should be changed to a plate
`41' which scatters the light. Also, original 8 should have
`a transparency.
`Referring to FIG. 9, a basic arrangement of the CCD
`and electric circuit parts for processing the signal pro
`duced from the CCD, according to the present inven
`tion, are shown.
`45
`CCD array 12 comprises an array of light receiving
`elements, such as photocells 120, a transfer gate array
`121 and an array of shift registers 122. Light receiving
`element array 120 is defined by N sensors S1-SN so as to
`receive reflected lights from reading line RL, which is
`divided into N picture elements. Thus, each sensor
`receives data from one picture element. Data of light is
`accumulated as an electric charge in each sensor, and
`the accumulated charge is transferred through transfer
`gate array 121 to analog shift register array 122. The
`55
`transferred charges are sequentially shifted by clock
`pulses d1 and d2 to output buffer 123 which produces
`a voltage signal Vo. After the every transfer of data
`from shift register 122, a reset pulse dbR is applied to
`output buffer 123 to reset the same. The voltage signal
`Vo from output butter 123 is applied to a sample/hold
`circuit 124 and further to a subtraction circuit 125.
`In subtraction circuit 125, data corresponding to the
`afterglow of G-lamp obtained during the separation of
`red data is subtracted from the red data, and data corre- 65
`sponding to the afterglow of G-lamp obtained during
`the separation of blue data is subtracted from the blue
`data. Furthermore, no subtraction is carried out during
`
`

`

`5
`
`4,642,679
`7
`8
`multiplier 222 are Se memory 221a and Si memory
`The B-separation period TB is divided into a period
`B in which the image reading is carried out under the
`221b, each defined by N-bit register. Se memory 221a
`light of the B-lamp as lit by an electric power, and a
`memorizes green data of a white image in the form of N
`period B2 in which the read blue data is processed and
`picture elements obtained when white zone 70 is ex
`converted into digital signal in A/D converter 203.
`posed by the afterglow of the region Se (FIG. 11) at the
`The subscript Madded to the character representing
`very beginning of a scan, i.e., before the start reading of
`the periods indicates the number of reading lines. The
`an original. Similarly, Simemory 22.1a memorizes green
`original is shifted by one pitch when the subscript M
`data of a white image in the form of N picture elements
`increases by one.
`obtained when white zone 70 is exposed by the after
`The frequency of the clock pulses d1 and d2 for
`glow of the region Si (FIG. 11) at the very beginning of
`10
`driving the CCD is fo when the read data is processed
`a scan, i.e., before the start reading of an original. When
`and converted in A/D converter 203, and during the
`the reading of one original or a number of originals is
`waiting period TW. In the other periods, the frequency
`completed, Se memory 221a and Si memory 221b are
`is increased to 4 fo so as to transmit the data out from
`reset and will receive a new data before the reading of
`shift register 122 to output buffer 123 as fast as possible,
`15
`a next original.
`thereby preventing the accumulation of unwanted data
`A buffer 202 temporarily holds and produces the
`in shift register 122. The period for reading the image
`voltage Vo' which is applied to shading corrector 126
`and the period for processing the data and the A/D
`which comprises A/D converter 203, D/A converter
`conversion are effected at different time. This is to
`231, and memories 230a, 230b and 230c. A/D converter
`avoid any error reading caused by the light impinging
`203 is coupled to a D/A converter 231 which is further
`on shift register 122.
`coupled to G-memory 230a, R-memory 230b and B
`Next, the operation of the color image reading device
`memory 230c, each defined by N-bit register.
`of FIG. 1 will be described.
`G-memory 230a memorizes green data of a white
`The operation is mainly divided into three operations,
`image in the form of N picture elements obtained when
`which are: an afterglow data storing operation for stor
`25
`white zone 70 is exposed by the afterglow of the region
`ing data in memories 220, 221a and 221b effected at the
`Sb (FIG. 11) at the very beginning of a scan.
`very beginning of the thorough operation at which
`Similarly, R-memory 230b memorizes red data of a
`white Zone is located in alignment with reading line RL;
`white image in the form of N picture elements obtained
`a shading reference setting operation (or white level
`when white zone 70 is exposed by the region Sf at the
`setting operation), which is effected immediately after
`very beginning of a scan. When the red light is emitted
`the afterglow data storing operation, for storing data,
`at the region Sf, the afterglow of green light (region Se)
`obtained at the white zone, in memories 230a, 230b and
`still exists, but this can be eliminated in a manner which
`230c and an original reading operation in which the
`will be described later.
`read data representing the original is corrected at sub
`Likewise, B-memory 230c memorizes blue data of a
`traction circuit 125 to eliminate noise signals due to the
`35
`white image in the form of N picture elements obtained
`afterglow and further corrected at shading circuit 126
`when white zone 70 is exposed by the region Sj at the
`to effect the white balance.
`very beginning of a scan. When the blue light is emitted
`First, by the rotation of pulse motor 210, a platform is
`at the region Sj, the afterglow of green light (region Si)
`moved to an initial position at which the white zone 70
`still exists, but this can be eliminated in a manner which
`is aligned to reading line RL. Under this condition, the
`will be described later.
`afterglow data storing operation and the shading refer
`. When the reading of each line on the original is ef.
`ence setting operation are carried out.
`fected, the read data is compared and normalized by the
`The afterglow data storing operation will be de
`data stored in memories 230a, 230b, and 230c. If the
`scribed below in connection with FIGS. 1, 11 and 12.
`original is pure white, the read data should have the
`Referring particularly to FIG. 12, the G-lamp is lit by
`45
`same data as the data stored in memories 230a, 230b and
`the signal GFL in the period Gl. Then, in the next
`230c. In this case, the data produced from A/D con
`period G2, utilizing the region Sb of the afterglow,
`verter 203 will have a 100% level for each of the three
`CCD charges green data which has been reflected from
`color signals.
`the white zone. During the afterglow data storing oper
`A pulse motor drive circuit 206 is coupled to a pulse
`ation, a signal Tx applied to multiplier 222 is maintained
`motor 210 which moves platform 7 bit-by-bit each time
`HIGH so that no signal is provided from multiplier 222
`the motor 210 is rotated.
`to D/A converter 223. Thus, during this operation,
`As shown in FIG. 11, one cycle operation for reading
`D/A converter 223 generates no subtraction current.
`one line includes a G-separation period TG, an R-sepa
`Thus, the voltage Vo, carrying the green data of white
`ration period TR, a B-separation period TB and a wait
`Zone, is transmitted through junction J1, buffer 202 to
`55
`ing period TW.
`A/D converter 203 with no substantial change. Then, in
`The G-separation period TG is divided into a period
`the next period G3, the voltage Vo is converted to a
`Gl in which the G-lamp is supplied with an electric
`digital data in A/D converter 203, and the converted
`power, a period G2 in which the image reading is car
`data is stored, e.g., in G-memory 230a, in response to a
`ried out, under the light of afterglow, by the photocells
`signal Ts.
`60
`in CCD array 12, and a period G3 in which the read
`It is to be noted that the data stored in Sb memory 220
`green data is processed and converted to digital signal
`is defined by N binary signals representing N picture
`in A/D converter 203.
`elements, respectively, and at this period, each of N
`The R-separation period TR is divided into a period
`binary signals is weighted as having a level equal to one,
`R in which the image reading is carried out under the
`indicating that the image is white throughout.
`65
`light of the R-lamp as lit by an electric power, and a
`Then, in the period R1, CCD detects afterglow data
`period R2 in which the read red data is processed and
`of green light corresponding to the region Se. Since no
`converted into digital signal in A/D converter 203.
`subtraction is carried out, the voltage Vo now carrying
`
`30
`
`SO
`
`
`Ex.1038 / Page 16 of 20Ex.1038 / Page 16 of 20
`
`TESLA, INC.TESLA, INC.
`
`

`

`10
`
`5
`
`25
`
`4,642,679
`9
`10
`the green data of the afterglow in the region Se is trans
`junction J1, such as shown by waveform F, represents
`mitted to A/D converter 203 without any substantial
`an image of the white zon