United States Patent [19]
`Kitta et al.
`
`[11] Patent Number:
`[45] Date of Patent:
`
`4,678,338
`Jul. 7, 1987
`
`[54] COLOR SENSOR
`[75]
`Inventors: Kenichi Kitta, Tokyo; Yasunori
`Kanazawa, Hachioji; Yoshiro Otomo,
`Mitaka, all of Japan
`[73] Assignee: Hitachi Maxell, Ltd., Osaka, Japan
`[21] Appl. No.: 554,363
`[22] Filed:
`Nov. 22, 1983
`Foreign Application Priority Data
`[30]
`Japan ................................ 57-203762
`Nov. 22, 1982 [JP)
`Japan ................................ 57-203763
`Nov. 22, 1982 [JP]
`Japan ................................ 57-206856
`Nov. 27, 1982 [JP]
`Japan ................................ 57-206857
`Nov. 27, 1982 [JP)
`Int. C1.4 ................................................ G01J 3/50
`[51]
`[52] u.s. Cl •.................................... 356/402; 356/420;
`250/226
`[58] Field of Search ................... 356/41, 44, 402, 406,
`356/407, 409, 410, 411, 414, 420, 425, 40, 446;
`250/564, 565, 226; 209/577, 580, 581, 582
`References Cited
`U.S. PATENT DOCUMENTS
`3,449,053 6/1969 Cannady eta!. .................... 356/407
`3,593,055 7/1971 Geusic eta!. .................... 250/458.1
`3,609,044 9/1971 Murphy ............................... 356/446
`3,709,615 1/1973 Blakeslee eta!. ................... 356/225
`3,725,701 4/1973 Link .................................... 250/343
`3,910,701 10/1975 Henderson eta! ................... 356/39
`3,942,185 3/1976 Lebailly .............................. 250/226
`3,986,777 10/1976 Roll ..................................... 250/226
`
`[56]
`
`3,994,590 11/1976 Di Martini eta!. ................. 356/409
`4,232,971 11/1980 Suga .................................... 356/402
`4,241,738 12/1980 Lubbers eta!. ....................... 356/40
`4,278,349 7/1981 Sander .................................. 356/44
`4,476,982 10/1984 Paddock et al. .................... 356/406
`4,494,875 1/1985 Schramm et al. ................... 356/402
`
`-
`FOREIGN PATENT DOCUMENTS
`2116386 10/1972 Fed. Rep. of Germany ...... 356/420
`0016826 2/1981 Japan ................................... 356/402
`0012352 1/1982 Japan ................................... 356/446
`1410823 10/1975 United Kingdom ................ 356/402
`
`OTHER PUBLICATIONS
`"An On-Line Shade Monitor for Strip Materials," Purll
`et al., Optica Acta, v. 25, No. 12, Dec. 1978, p. 1197.
`
`Primary Examiner-F. L. Evans
`Attorney, Agent, or Firm-Birch, Stewart, Kolasch &
`Birch
`
`ABSTRACT
`[57]
`A color sensor includes a plurality of light emitting
`source of different colors each of which is driven in a
`time divisional manner to emit the different colors se(cid:173)
`quentially, a light receiving element for receiving the
`light from an object illuminated by the respective color
`lights from the light emitting sources and a circuit ar(cid:173)
`rangement for producing output signals representing
`the color of the object.
`
`10 Claims, 11 Drawing Figures
`
`15
`
`Photo Sensing
`Unit
`
`Vizio EX1026 Page 0001
`
`

`

`U.S. Patent Jut 7, 1987
`
`Sheet 1 of4
`
`4,678,338
`
`Fl G.J Background Art
`
`F I G. 2 . Background Art
`
`Comparator
`
`6
`
`8
`7
`Photo Sensing
`Unit
`
`FIG.3
`
`18
`
`4
`
`Photo Sensing
`Unit
`
`Timing
`Circuit
`
`14
`
`f
`
`g
`
`Vizio EX1026 Page 0002
`
`

`

`U.S. Patent JuL 7, 1987
`
`Sheet2 of4
`
`4,678,338
`
`FIG.4
`
`---To~
`
`a
`b
`
`d
`
`e
`
`f
`
`g
`
`h
`
`8
`
`c
`
`L----0
`1
`0
`----~---t:----t---t--·-Vs
`
`'
`I
`
`~To I
`
`I
`
`---,---r-----, . ..._1! -~J .._li ___ .__ ~
`~~~n~~~~-~~h~~~-
`~~------r----'nl---1---r----i-n_
`
`I
`I
`
`l
`0
`
`!----:----!...--7---"T-- 0
`1
`0
`
`.
`
`I
`I
`I
`I
`I·
`I
`
`I
`.I
`I
`I
`
`1
`L-~-~-~~--~~--0
`
`EX
`
`FIG.5
`
`Vizio EX1026 Page 0003
`
`

`

`U.S. Patent
`
`JuL 7, 1987
`
`Sheet3 of4
`
`4,678,338
`
`<.0
`
`<.9 -lL
`
`c:.,_ o._
`:~~ au
`
`Vizio EX1026 Page 0004
`
`

`

`U.S. Patent JuL 7, 1987
`
`Sheet4 of4
`
`4,678,338
`
`FIG.?
`
`Time Division
`Drive Circuit
`
`15
`.------J-'-----i h
`0 s Q t-L----1"""i
`
`B
`c
`
`Timing
`Circuit
`
`f
`
`1----r::-g - - - - j
`
`FIG. 8
`Q-ua
`
`30a
`
`FIG.IO
`(J-ua
`I \
`
`FIG.//
`
`/Ia
`
`Photo Sensing
`Unit
`
`Vizio EX1026 Page 0005
`
`

`

`1
`
`COLOR SENSOR
`
`4,678,338
`
`2
`ventional color sensors is limited by the colGr of the
`filter 5, or the color of the light emitting diode 1. For
`example, when a red color filter or a red light emitting
`diode is used, the color sensor can recognize only
`whether the color of the object is red or not.
`One way of recognizing more than three colors of the
`objects is to provide an arrangement for interchanging
`a plurality of filters of various kinds of colors in place of
`the color filter 5 in FIG. 1. For example, assuming that
`objects each having one of at least four different color
`groups such as red, green, yellow and a group consist(cid:173)
`ing of all other colors are to be classified, red objects are
`classified using a red filter, subsequently green objects
`are classified using the green filter. The same operation
`is performed using the yellow filter and the remaining
`color filter to classify the yellow objects and other color
`objects are left undetected so that the objects can be
`classified into four color groups.
`This method, however, requires to the repetition of
`the identifying means for each of the colors correspond(cid:173)
`ing to the number of the kinds of the interchangeable
`color filters. Accordingly it takes much time and work
`to classify the color of the objects, and it further re(cid:173)
`quires updating the reference voltage of the comparator
`8 each time the color filters are interchanged.
`Another method of classifying the color of the ob(cid:173)
`jects having more that three colors is to provide a plu(cid:173)
`rality of color sensors for each of the colors to be classi(cid:173)
`fied. For example, if there are four colors to be classi(cid:173)
`fied, four color sensors each having a different color
`filter are employed. This method is effective to decrease
`the time for classifying the objects into four colors by
`placing each of the color sensors along the line of flow
`of the objects. However, the number of color sensors
`used increases as the number of the colors to be classi(cid:173)
`fied increases. Furthermore, in order to recognize the
`various colors correctly, the respective color sensors
`must have a uniform sensing characteristics. If there is
`dispersion of the color sensing characteristics among
`the respective color sensors due to the difference of the
`brightness of the light sources, the difference of the
`color filtering characteristics and/or the difference of
`the sensitivity of the respective photo sensing units,
`setting of the reference voltage of the respective com(cid:173)
`parators of the color sensors is very difficult.
`
`FIELD OF THE INVENTION
`The present invention relates to a color sensor for 5
`recognizing the hue of articles by sensing rays of light
`passed through or reflected from the articles.
`
`BACKGROUND OF THE INVENTION
`In order to identify a desired kind of articles when 10
`among various other kinds of articles in a manufactur(cid:173)
`ing process, it is well known to use a method of identify(cid:173)
`ing the hue or color of the articles or objects.
`FIG. 1 shows an example of a conventional color
`sensor for recoginizing color of articles. Referring to 15
`FIG. 1, rays of white light are emitted from a light
`source 1 made of a tungsten lamp and a portion of the
`rays of light is reflected by a half mirror 2. The light
`reflected by the half mirror 2 is collimated by a lens 3 at
`a position at which an article or an object to be recog- 20
`nized is placed. Each of the objects has identifying a
`specific color given to it either by the color of the mate(cid:173)
`rial forming the object or by a label or mark attached on
`the surface of the object. The light reflected by the
`object is changed into a parallel light by the lens 3 and 25
`is received by a photo sensing unit 6 after passing
`through the half mirror 2 and a color filter 5. The color
`filter 5 has a specific spectral characteristic of transpar(cid:173)
`ency corresponding to the desired hue or color of the
`object sought so as to allow the light of the color of the 30
`object sought to pass through the filter. The output
`signal of the photo sensing unit 6 is amplified by an
`amplifier 7 and in turn applied to a comparator 8. The
`output signal of the amplifier 7 is compared with a
`reference voltage applied to the one input terminal of 35
`the comparator 8. The comparator produces a digital
`signal (e) that is a high level output (referred to.as 1
`hereinafter) or a low level output (referred to as 0 here(cid:173)
`inafter) depending on whether or not the output level of
`the amplifier 7 exceeds the reference voltage. The con- 40
`tents of the digital signal (e) i.e., 1 or 0 represent
`whether or not the photo sensing unit 6 receives the
`reflected light, accordingly the content of the digital
`signal (e) represents the hue of the object.
`FIG. 2 is another example of a conventional color 45
`sensor and the reference numerals 9 and 10 show optical
`fibers respectively. In FIG. 2 like parts in FIG. 1 are
`designated by the same reference numerals. In this con(cid:173)
`ventional color sensor, a light emitting diode is used as
`the light source 1 and the light of the light source 1 is 50
`projected on the object 4 through the optical fiber 9.
`The light reflected by the object 4 is passed through the
`optical fiber 10 and received by the photo sensing unit
`6.
`
`According to the color sensor shown in FIG. 2, the 55
`light source is a light having the same color as the de(cid:173)
`sired color so that the filter 5 provided in the color
`sensor in FIG. 1 can be omitted and the area of the light
`emitting port of the optical fiber can be minimized and
`furthermore the light emitting port can be placed at 60
`very near the object so that the radius of sp.ot light
`incident to the object can be minimized, thereby reduc(cid:173)
`ing the total size of the color sensor per se as compared
`to the color sensor shown in FIG. 1 and enabling the
`recognition of the color of smaller sized objects.
`However, the conventional color sensors as de(cid:173)
`scribed above are not capable of recognizing three or
`more colors because the recognizable color in the con-
`
`SUMMARY OF THE INVENTION
`An essential object of the present invention is to pro-
`vide a color sensor which is able to recognize more than
`three kinds of colors or hues with a simple construction
`and with an easy adjustment of the various parts of the
`color sensors.
`According to the present invention there is provided
`a color sensor including a plurality of light emitting
`sources, each being capable of emitting different color
`lights respectively for driving said light sources in a
`time divisional manner so as to emit said different color
`lights in time sequentially one after another; sequen(cid:173)
`tially projecting the emitted different color lights onto
`an object, the color of which is to be sensed; light re(cid:173)
`ceiving means for receiving the lights reflected from or
`passed through the object and producing output signals
`65 representing the value of the lights from the object
`corresponding to each of the different color lights; and
`circuit means for recognizing the color of the object by
`the output signals of the light receiving means.
`
`Vizio EX1026 Page 0006
`
`

`

`4,678,338
`
`3
`BRIEF DESCRIPTION OF THE DRAWINGS
`FIG. 1 is a schematic diagram showing one example
`of a conventional color sensor,
`FIG. 2 is another example of a conventional color 5
`sensor,
`FIG. 3 is a schematic diagram showing one example
`of an embodiment of a color sensor according to the
`present invention,
`FIG. 4 is a schematic diagram showing wave forms of 10
`the essential portion of the color sensor shown in FIG.
`3,
`
`4
`tier 7 with the reference voltage to provide an output of
`1 or 0 depending on whether or not the analog signal
`exceeds the reference voltage.
`Two flip-flops 15 and 16 of D type receive the output
`of the comparator 8, i.e. the digital signal e to hold
`thereof at the timing when every strobe pulses f, g are
`applied. The flip-flops 15 and 16 form a signal holding
`circuit.
`AND gates 17, 18, 19 and 20 form a logic circuit to
`calculate a logic of recognizing the colors of the object
`on the basis of the level of the digital signal e held in the
`hold circuit.
`Referring to FIGS. 3 and 4, a timing circuit 14
`supplies timing signals to the time divisional drive cir-
`15 cuit 13, which produces drive current a and b to drive
`the light emitting sources 1a and 1b with a phase differ(cid:173)
`ence of 180° and period of To with a duty ratio of 50%.
`By this arrangement the light emitting sources 1a and
`1b emit the red light and the green light alternately,
`whereby the red light and the green light are projected
`on the object 4 in a time divisional manner passing
`through the entrance 11a and the light transmission path
`11. It is to be noted that the periods during which the
`light emitting source 1a emits the light are designated
`by t1 through t3 and ts through t7, and the period during
`which the light emitting souce 1b emits the light is
`designated by t3 through ts.
`The object 4, illuminated, reflects the light of a color
`corresponding to the color of the surface of the object
`30 and the reflected light passes the exit llc and the light
`transmission path 11 and is received by the photo sens(cid:173)
`ing unit 6, which produces an analog signal of a large
`amplitude when the reflected light is received. As a
`shown in FIG. 4 assuming that the object 4 having red
`color is illuminated from the timing t1. the amplitude of
`the analog signal of the output of the photo sensing unit
`6 becomes large in the time periods t1 through t3 and ts
`through t7 during which the light emitting source 1a
`emits the light because the red object 4 reflects the red
`light and absorbs the green light, and the amplitude
`becomes small in the period t3 through ts during which
`the light emitting source 1b emits the light.
`The analog signal from the photo sensing unit 6 is
`amplified by the amplifier 7 to produce the analog sig(cid:173)
`nal d of the predetermined amplitude and is fed to the
`comparator 8 to be compared with the reference volt-
`age Vs. The comparator 8 produces the digital signals e,
`the level of which is 1 in the periods h through t3 and ts
`through t7 during which the amplitude of the analog
`signal is large, and is 0 in the period t3 through ts during
`which the amplitude of the analog signal is small.
`The digital signals produced by the comparator 8 are
`fed to the D input terminals of the flip-flops 15 and 16
`which receive the strobe pulses f and g at the T input
`terminals from the timing pulse generator 14. The D
`type flip-flop 15 holds the level of the digital signal e at
`the time of the positive edge of each of the strobe pulses
`f and the D type flip-flop 16 holds the level of the digital
`signal e at the positive edges of each of the strobe pulses
`g. By this operation, the output of the D type flip-flop
`15 becomes 1 upon receipt of the strobe pulse f at the
`timing.t2 in the periods of t1 through t3 thereby the Q
`output thereof being 1 with the Q output being 0. The 1
`level of the Q output of the flip-flop 15 shows the object
`4 has red color and the 1 level is held by the next posi(cid:173)
`tive edge of the strobe pulse f.
`Since the digital signal e in the period t3 through ts is
`0, the Q output of the D type flip-flop 16 becomes 0
`
`FIG. 5 is a front view showing a way of distributing
`the optical fibers of a light transferring path used in the
`embodiment shown in FIG. 3,
`FIG. 6 is a further example of the color sensor ac(cid:173)
`cording to the present invention,
`FIG. 7 is a schematic diagram showing a still further
`example of the color sensor according to the present
`invention,
`FIG. 8 is a cross sectional view of an example of light
`emitting unit used in the color sensor according to the
`present invention,
`FIGS. 9 and 10 are schematic diagram showing still
`further modification of the light emitting units used in 25
`the color sensor according to the present invention, and
`FIG. 11 is a schematic diagram showing an example
`of a color sensor having one colored light emitting
`source using a light transferring path with one end por(cid:173)
`tion formed as shown in FIG. 5.
`
`20
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENTS
`Referring now to FIG. 3 there are provided two light
`emitting sources la, 1b using light emitting diodes of 35
`different colors such as red and green, each of the light
`emitting sources 1a and 1b is driven to emit the red light
`and the green light alternately by a time divisional drive
`circuit 13 in a time divisional manner. A light transmis(cid:173)
`sion path 11 is formed by a plurality of optical fibers 40
`::: bundled together with a part of the one end of bundled
`optical fibers of the light transmission path 11 opposed
`adjacent to the light emitting sources 1a and 1b to form
`a light entrance 11a to which the light from the light
`emitting sources 1a and 1b is enters and the remaining 45
`part of the said one end of the optical fibers opposed to
`the photo receiving unit 6 to form a light exit llb to
`project the light reflected from the object 4 on the
`photo sensing unit 6. The other ends of the part of the
`optical fibers forming the light entrance 11a are dis- 50
`posed to face the object 4 to form the light exit llc of
`light to project the light of the light emitting sources 1a
`and 1b on the object 4. The other ends of the remaining
`part of the optical fibers forming the light exit 11b for
`the photo sensing unit 6 are disposed to face the object 55
`4 to form the light entrance 11c for receiving the light
`reflected from the object 4. At the end, 11c, of the light
`transmission path 11, the respective optical fibers EX
`for receiving the light and the optical fibers PR for
`projecting the light are distributed alternately as shown 60
`in FIG. 5 to receive or project the light uniformly over
`the entire area of the end, 11c.
`The photo sensing unit 6 is formed by a single photo
`transistor to produce an analog signal corresponding to
`the quantity of the incident light to the photo transistor. 65
`The comparator 8 is applied with a reference voltage
`at one of the input terminals and compares the analog
`signal applied to another input terminal from the ampli-
`
`Vizio EX1026 Page 0007
`
`

`

`4,678,338
`
`10
`
`5
`upon receipt of the positive edge of the strobe pulse gat
`the timing t4 in the period t3 through ts with the Q out(cid:173)
`put of thereof being 1. The 0 level of the D type flip-flop
`16 shows that the photo sensing unit 6 does not receive
`the green light and the 0 level is held until the next 5
`strobe pulse g is applied.
`The table I shows the relation of the output of flip(cid:173)
`flops 15 and 16 and the absense or presence of the light
`of the respective colors incident to the photo sensing
`unit 6.
`The AND gates 17, 18, 19 and 20 judge the states of
`the flip-flops 15 and 16 to generate signals representing
`the hue of the objects. As shown in FIG. 3, the AND
`gate 18 receives the output signals h and k, the AND
`gate 19 receives the output signals i andj, and the AND 15
`gate 17 receives the output signals i and k.
`Although the timings of the light emission by the
`light emitting sources la and lb are shifted by T 0/2 each
`other, as the timings of the strobe pulses f and g are also
`shifted by T ol2 and the state of the output of the D type io
`flip-flop 15 can be held until the other flip-flop 16 reads
`in the output of the comparator 8 upon receipt of the
`strobe pulse g, the AND gates 17 through 20 receive the
`signals h, i, j, and k simultaneously. In FIG. 4 Y is the
`period for holding the output of the comparator 8 and X 25
`is the period for judging the state of the output of the
`flip-flops.
`The relationship between the color of the object and
`the states A, B, C and D of the outputs of the AND
`gates 17, 18, 19 and 20 is shown in the table 2. As under- 30
`stood from the table 2, when the color of the object is
`red, only the output B of the AND gate 18 is 1 with the
`remaining outputs A, C and D being 0. In the table 2,
`the term "other color" means a color other than red,
`green, white and yellow.
`According to the first embodiment of the color sen(cid:173)
`sor according to the present invention, the four kinds of
`hues can be recognized or classified by using only two
`color light emitting sources and the recognition of the
`hue can be made in the real time basis. In this embodi- 40
`ment, the currents of the light emitting diodes la and lb
`are so adjusted that the intensity of the lights of the light
`emitting diodes la and lb is equal. Thus if the color of
`the objects is yellow, the quantity of the red light and
`green light reflected from the object 4 and received by 45
`the photo sensing unit 6 is lower than quantity of the
`reflected light of the object having red or green, eventu(cid:173)
`ally the output amplitude of the amplifier 7 for the yel(cid:173)
`low object is smaller than that for the red or green
`object. Thus, the reference voltage of the comparator 8 50
`is set to recognize the yellow by setting the reference
`voltage in such a manner that the comparator 8 gener(cid:173)
`ates 1 in both cases when the red light is illuminated and
`when the green light is illuminated.
`Since the red light and the green light are emitted in 55
`a time divisional manner, only one comparator 8 is
`necessary for digitizing the analog signal fed from the
`amplifier or the photo receiving unit 6, so that only one
`reference voltage must be used for the both of the red
`and green lights, thereby facilitating adjustment of the 60
`reference voltage without consideration about the bal(cid:173)
`ance of the reference voltage for each of colors.
`It is not essential to use a light transmission path but
`the path can be two separate paths 9 and 10 as shown in
`FIG. 2 one for illuminating the light on the object and 65
`another for receiving the reflected light from the object.
`FIG. 6 shows the second embodiment of the color
`sensor according to the present invention wherein the
`
`6
`light entrance 11a of the light transmission path 11 is
`divided into two light entrances 11al and 11a2 by divid(cid:173)
`ing the bundled optical fibers two groups. The light
`entrance llal is disposed to face adjacent to the red
`light emitting source la and the light entrance 11a2 is
`disposed to face to the green light source lb.
`FIG. 7 shows the third embodiment of the color
`sensor according to the present invention wherein the
`light entrance 11a of the color sensor shown in FIG. 3
`is connected with a light emitting unit 20 having a box(cid:173)
`like enclosure 21 made of an opaque material. The light
`emitting source la and lb are respectively fixed to one
`face 2la of the enclosure 21 with the light emitting faces
`of the light emitting sources la and lb directed to the
`opposite face 2lb on which the light entrance 11a of the
`light transmission path 11 is connected. The enclosure
`21 is separated by a light diffuser 22 such as a sheet of
`frosted glass disposed between the both faces 2la and
`2lb. By this arrangement, the light emitted from the
`light emitting source la and/or lb is diffused by the
`light diffuser 22 and in turn the diffused light enters the
`light entrance lla. By using the light diffuser 22, direc(cid:173)
`tionality of the light emitting sources such as light emit(cid:173)
`ting diodes can be broadened so that the intensity of the
`light entering the light entrance lla from both of the
`light emitting sources la and lb becomes uniform. The
`color recognition operation is similar to the arrange(cid:173)
`ment shown in FIG. 3.
`In order to broaden the directionality of the light
`emitting diodes la and lb, hemispherical enclosure 30
`may be used as shown in FIG. 8. In this embodiment,
`the light emitting diodes la and lb are mounted on the
`35 flat face of the enclosure 30 which is filled with a light
`diffusing material. The light entrance lla of the light
`transmission path 11 is disposed to oppose the apex 30a
`of the hemispherical portion of the enclosure 30.
`As the light emitting diodes, GaAIAs diode la for the
`red light and GaAs:Si diode lb for the infra red light
`may be used. For the light diffusing material, as shown
`in FIG. 9, anti-Stokes fluorescent material 31 may be
`filled in the enclosure uniformly, so that green light may
`be emitted by the infra red light emitted from the light
`source lb. Although the shape of the enclosure is not
`limited to the hemispherical shape, in the case of the
`hemispherical shape the, quantity of the light entering
`the light transmision path may be increased.
`Another modification of the light emitting unit is
`shown in FIG. 10, wherein a layer 40 made of anti(cid:173)
`Stokes fluorescent material is interposed between the
`GaAs:Si diode 41 and the flat face of a hemispherical
`enclosure 42 made of transparent material.
`The Ga AS:Si diode 41, the layer 40 and the flat face
`of the enclosure 42 may be adhered integrally. The
`enclosure 42 acts as a lens to collimate both of the lights
`from the diodes la and 41 to the light entrance lla.
`The bundled optical fibers with the end portions PR
`and EX thereof so uniformly distributed as shown in
`FIG. 5 may be used for the color sensor having one
`color light emitting source 1 as shown in FIG. 11.
`Although the embodiments of the color sensor de(cid:173)
`scribed above are provided with two light emitting
`sources of different colors, the number of the colors of
`the light emitting source is not limited to two but n
`kinds of color light sources may be used to recognize 2n
`kinds of colored objects.
`
`Vizio EX1026 Page 0008
`
`

`

`4,678,338
`
`States of flip-flops
`
`D type flip-flops 15
`
`D type flip-flops 16
`
`7
`TABLE 1
`Q
`Q
`I
`0
`I
`0
`
`0
`I
`0
`I
`
`"I"
`"0"
`"I''
`"0"
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`·Photo sensing unit 6
`
`red light is present
`red light is absent
`green light is present
`green light is absent
`
`8
`3. The color sensor of claim 2 wherein said four col(cid:173)
`ors include red, green, yellow and another color.
`4. The color sensor of claim 1 further comprising
`light transferring means for providing light from said
`5 first and second illumination means to said object and
`from said object to said means for monitoring.
`5. The color sensor of claim 4 wherein said light
`transferring means comprises:
`a plurality of optical fibers bundled together with a
`portion of said bundle of said optical fibers having
`a first end at a first light receiving point facing said
`first and second illumination means to form a first
`light entrance for receiving light from said first and
`second illumination means and the remaining por-
`tion of said bundle of the optical fibers having a
`first end facing said means for monitoring to form
`a first light exit to the means for monitoring; a
`second end of the bundle of said optical fibers fac-
`What is claimed is:
`ing said object to form a second light entrance for
`1. A color sensor for recognizing the relative color of
`receiving the light from the object and a second
`an object comprising:
`first illumination means for supplying light of a first
`light exit for projecting the light on the object.
`wavelength to said object;
`6. The color sensor according to claim 5, wherein the
`second end of said bundled optical fibers is so formed
`second illumination means for supplying light of a
`that each of the optical fibers forming the second light
`second wavelength different from said first wave-
`length to said object;
`25 entrance and the second light exit is distributed to re-
`means for monitoring said light of said first and sec-
`ceive the light from the object and to project the light
`to the object uniformly over the entire area of the sec-
`ond wavelengths from said object, and means for
`ond end of the bundled optical fibers.
`monitoring including,
`7. The color sensor according to claim 4, wherein the
`a single photosensor producing an output indica-
`tive of the quantity of light received from said 30 first and second illumination means are mounted on one
`wall member of an enclosure with said light transferring
`object, and
`comparator means for comparing the output of said
`means mounted on an opposing wall member of said
`single photosensor to a reference value, the out-
`enclosure, said enclosure being provided with light
`put of said comparator being a logical one when
`diffusing means disposed between said first and second
`light supplied said photosensor exceeds said ref- 35 illumination means sources and said light transferring
`erence value and being otherwise a logical zero;
`means.
`8. The color sensor according to claim 7, wherein
`timing control means for generating first and second
`alternate enable signals to enable said first and
`said enclosure is a box.
`9. The color sensor according to claim 4, wherein the
`second illumination means, alternately; and
`hue determination means, operatively connected to 40 first and second illumination means are mounted on a
`flat wall member of an enclosure with the light emitting
`said timing control means, for retaining the logical
`values developed by said comparator means, said
`portion of the first and second illumination means di-
`hue determination means receiving first and second
`rected to a wall member of the enclosure to which a
`phase shifted latch timing signals developed by said
`light entrance of said light transferring means is faced,
`timing control means to reset said hue determina- 45 said enclosure is of a hemispherical shape with the in-
`tion means, said hue determination means develop-
`side filled with a light diffusing material.
`ing at least three logical outputs, each representa-
`10. The color sensor according to claim 7 wherein
`tive of the presence or absence of a different color
`said light diffusing means is a fluorescent material and
`of said object.
`the respective first and second illumination means are
`2. The color sensor of claim 1 wherein said hue deter- 50 light emitting diodes of different colors, one of said light
`mination means develops four outputs representative of
`emitting diodes being an infra red light emitting diode.
`* * * * *
`four colors.
`
`State of
`flip-flop 15
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`State of
`flip-flop 16
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`0
`I
`0
`I
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`0
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`TABLE2
`output of
`AND gates
`A B c D
`I
`0
`0
`0 other color
`I
`0
`0
`0
`red
`I
`0 yellow
`0
`0
`I yellow & white
`0
`0
`0
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`hue of
`the object
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`10
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`15
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`20
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`55
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`60
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`65
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`Vizio EX1026 Page 0009
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