Ex. GOOG 1021
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`EX. GOOG 1021
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`Kihara, Nakamura, Saito, Kambara: The Electronic Still Camera A New Concept in Photography
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`325
`
`THE ELECTRONIC STILL CAMERA A NEW CONCEPT IN PHOTOGRAPHY
`
`N. Kihara, K. Nakamura, E. Saito and M. Kambara
`Advanced Engineering Division
`Development Center
`Sony Corporation
`Shinagawa-ku, Tokyo 141 Japan
`
`1 INTRODUCTION
`Considerable interest has been shown in recent years
`in electronic systems of photography which use no film.
`In 1972, for instance, Texas Instruments filed a patent
`for an electronic camera(l) and in 1980 Polaroid intro(cid:173)
`duced their concept of an instant electronic camera.<2>
`This paper reports the development of a new
`electronic camera, the first of its kind, which employs
`a CCD solid state imager and a reuseable magnetic disc
`on which up to 50 pictures can be recorded. The
`pictures can be easily transmitted over a telephone line
`and this camera can also function as a compact, light(cid:173)
`weight color video camera.
`A playback unit which will allow the pictures to
`be viewed immediately on an ordinary TV set is also
`reported. Using the color video picture printer whose
`development is reported elsewhere, it is possible to ob(cid:173)
`tain hard copies.
`
`2 CAMERA'S CONFIGURATION
`Fig. 1 is a perspective view of the camera. The
`camera employs a CCD solid state imaging device to
`record images on a magnetic disc. We will first discuss
`the CCD, the camera's signal processing circuitry, and
`its disc drive.
`
`release
`selftimer
`
`function switch
`
`finder
`
`recording circuitr
`
`CCD drive
`CirCUit
`
`battery
`
`magnetic disc
`
`lens
`Fig. 1 Perspective view of the electronic still camera
`Manuscript Received 6/11/82
`
`CCD imager
`
`2.1 CCD Imager
`A schematic diagram of the CCD we employed is
`shown in Fig. 2. The chip size is 11.0 x 12.1 mm.
`Its image area is 6.6 x 8.8 mm. Thus, the CCD imager
`fits a 2/3-inch optical system. The imaging area consists
`of 570 x 488 pixels. The image signal generated in
`this area is transferred to a storage area during the
`vertical blanking period, after which it is read out from
`the readout register triggered by a clock signal. A
`stripe filter of red, green and cyan is used as a color
`filter.
`
`o-----
`
`o-----
`
`o-----
`o---
`
`o - -
`
`~c
`
`11111111
`Imaging Area
`II II I I I I
`570H X 488V pixels - - ( )
`
`--o
`
`Storage Area
`
`- - ( )
`
`~
`
`f----o
`
`VO
`
`~
`
`oo~os
`
`Fig. 2 Schematic diagram of CCD
`
`0098-3068/82/0325-0331$00.75 © 19821EEE
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`IEEE Transactions on Consumer Electronics, Vol. CE-28, No. 3, August 1982
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`The CCO is designed to take advantage of the
`narrow channel effed3) in which an electric potential
`change is produced when the width of the electrode of
`an MOS transistor narrows to about 2pm. A CCO which
`is designed in this way has the following advantages:
`the pixels can be aligned with a high density because the
`elements are very simple; the driving circuitry can be
`simplified and
`the power
`requirements minimized
`because the electrode overlap is small and because the
`device can be driven by two phase clocks, the device's
`spectral response -
`even in the blue wavelength -
`is high because light falls directly on the pixels. To
`counteract blooming, we
`incorporated an overflow
`drain without much deterioration of sensitivity to obtain
`a blooming suppression ratio of 120.
`
`2.2 Disc Drive Mechanism
`Fig. 3 is the disc drive. Its spindle shaft is driven
`by a very compact motor through servo-circuitry at a
`constant field frequency of 60rps. The drive mechanism
`is designed so that the disc can be positioned in the
`camera with sufficient accuracy in order that contact
`between the head and the disc is stable. The disc re(cid:173)
`volves at high speed but because its diameter is small,
`it is only slightly affected by aerodynamics and centri(cid:173)
`fugal force. The drive mechanism uses a guide plate to
`limit the tendency of the disc to lift off the video head.
`
`guide plate
`
`air =
`
`Fig. 4 Relation between guide plate, head and disc
`
`disc
`
`• with guide plate
`Values (0.6, 0.31' m) indicate space between the
`head and disc as measured by the interference
`fringe method. (The value 0.07 1' m is estimated
`by different means.)
`
`Fig. 3 Disc drive
`
`Fig. 4 shows the relation between the guide plate,
`the recording head and the disc. Note that an air
`cushion is formed between the guide plate and the disc.
`Fig. 5 shows the head-to-disc contact both with and
`without the guide plate. The space between the head
`and the disc was reduced to 0.07pm when the guide
`plate was used. Because of this stable contact, there is
`no need to apply pressure to bring the head and the
`disc together and the life of the disc is prolonged.
`
`• without guide plate
`Optimum contact is obtained outside of the head
`gap area.
`
`Fig. 5 Head-to-disc contact with and without guide plate
`
`The signal-to-noise ratio is unacceptable if the head
`is not positioned with relation to the track within
`±10pm. We have attempted to make the drive mecha(cid:173)
`nism as impervious to temperature change as possible,
`but the head's variance from the perfect tracking po(cid:173)
`sition can still be as much as ±30pm. The playback
`unit's tracking error correction system, which will be
`explained later, compensates for this variation.
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`Kihara, Nakamura, Saito, Kambara: The Electronic Still Camera A New Concept in Photography
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`327
`
`2.3 The Recording Format and the Recording Circuit
`In order to record a high-quality picture capable
`of producing a hard copy both the luminance and the
`chrominance signals must have good resolution and a
`good signal-to-noise ratio. In addition, as the circuitry
`has to be built in to a small space, the components must
`be simple. We chose a single-track format in which line(cid:173)
`sequential R-Y and B-Y are recorded with Y because of
`its simplicity. The vertical resolution of the chrominance
`signal deteriorates by 50% when the line sequential
`format is used but, as the horizontal resolution (which is
`determined by the IMHz bandwidth of the chrominance
`signal) is lower than the vertical resolution, there is
`no problem. We decided against a single-track format
`in which Y and the down-converted subcarrier are
`recorded because hue fluctuations caused by jitter
`increase if we try to expand the color signal bandwidth.
`Fig. 6 shows the frequency allocation of the Y
`and chrominance signal. As the figure shows, the Y
`bandwidth at the 50% luminance level is 4.5MHz and the
`horizontal resolution is 350 TV lines. The chrominance
`signal has a IMHz bandwidth.
`
`Chrominance
`
`Luminance
`
`Fig. 7 Block diagram of recording circuit
`
`the camera's circuit-boards which
`Fig. 8 shows
`integrated with specially developed LSis
`are highly
`and hybrid modules.
`
`I K
`
`2 .5
`
`I
`I
`
`6
`
`7.5
`
`MHz
`
`~ I
`
`1.2 1.3
`i I
`I
`I
`1 I
`R-GJ LB-G
`
`4 .5 'Mttz
`
`Fig. 6 Frequency allocation of recording circuit
`
`The Fig. 7 is a block diagram of the recording
`circuit. The image signal received at the CCD through
`the optical lens is converted to an electric signal. This
`signal is converted to Y (luminance), R (red), G (green)
`and Cy (cyan) signals by sample and hold circuits. And
`from G and Cy, the B signal is produced. These signals
`are fed to the processing amplifiers which output the
`YY, R'Y, G'Y and B'Y signals. Y'Y is added to the Sync
`signal and fed to the frequency modulator. R'Y, G'Y,
`B~' are fed to the matrix circuit, and converted to the
`color-difference signals (R-G, B-G). After the signals
`have been selected line-sequencially, they are fed out to
`the other frequency modulator. The two FM signals,
`after their bandwidth has been appropriately restricted,
`are mixed and fed to the recording amplifier. This signal
`is recorded by the video head on the magnetic disc.
`In this circuit, we use R-G and B-G, instead of R-Y and
`B-Y, as the color-difference signals because of the CCD
`circuitry.
`
`Fig. 8 Circuit-boards of the electronic still camera
`
`3. THE MAGNETIC DISC
`The magnetic disc is made of film. As can be seen
`in Fig. 9, it is protected by a plastic jacket measuring
`60x54x3mm and the disc and jacket together weigh
`just 8 grams. A disc can be easily removed and rein(cid:173)
`serted before all fifty pictures have been taken and all
`pictures recorded can be erased so the disc can be used
`over and over. The pictures are not, of course, subject
`to fading. Fig. 10 shows the recording pattern in which
`the recording head records the first image on the outer(cid:173)
`most track, then traces across the radius of the disc,
`recording subsequent images.
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`IEEE Transactions on Consumer Electronics, Vol. CE-28, No. 3, August 1982
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`FREQUENCY ( MHz l
`4
`
`5
`
`6
`
`7
`
`8
`
`9
`
`10
`
`0
`
`2
`
`3
`
`E
`ID
`-a
`
`..J -70
`1&1 > 1&1
`..J
`~ -eo
`;:)
`II.
`~
`;:)
`0
`
`-90
`
`0
`c(
`1&1
`%
`
`Fig. 9 Disassembled disc jacket
`
`Fig. 11 Frequency characteristics for metal alloy disc
`and oxide disc, compared at line speed of 5.5 m/sec.
`
`FIRST
`RECORDING TRACK
`
`LAST
`RECORDING TRACK
`
`-RECORDING TRACK
`
`Fig. 10 Recording pattern
`
`A major goal was to minimize the diameter of the
`disc. In order to do this, it was necessary to develop
`a disc on which .very high density recording was possi(cid:173)
`ble.
`In order to obtain the best possible magnetic
`characteristics, we coated the surface of the disc with
`ferromagnetic metal alloy powder for the first time,
`as opposed to metal oxide power. Fig. 11 compares
`the frequency characteristics of discs coated with
`both powders. The 8dB difference in output level
`allows the metal alloy disc to be approximately half
`the metal oxide disc in diameter.
`
`High-density recording is only possible to the extent
`the surface of the disc is smooth as a smooth surface
`minimizes modulation noise and limits the loss caused
`by the short wavelength. The surface smoothness of
`is about 0.07J..Lm peak-to-peak while
`previous discs
`that of the present disc is 0.05J..Lm peak-to-peak.
`The newly-developed disc is not magnetically oriented
`at the time the metal alloy powder is coated because,
`unlike tape which is recorded on longitudinally, the
`signal is recorded on tracks around the disc. In this way,
`we could limit the difference in magnetic characteristics
`caused by recording in circular tracks to less than 1 dB,
`so there is no practical problem. Fig. 12 shows the
`fluctuations in the magnetic characteristics through 1
`field, that is, through 1 revolution of the disc.
`
`Fig. 12 Output fluctuations due to magnetic directional
`characteristics
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`Kihara, Nakamura, Saito, Kambara: The Electronic Still Camera A New Concept in Photography
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`329
`
`The magnetic disc has a remanance (Br) of about
`2000 Gauss and a coercivity (He) of about 1200 Oe ,
`realizing a 0.8/-lm short wavelength recording system.
`A potential problem in a system which operates
`within such close tolerances is disc eccentricity . Eccen(cid:173)
`tricity is a problem in a single camera, of course , but
`it is also the major cause of lack of interchangeability
`of discs. Fig. 13 shows our solution to the problem of
`eccentricity. When the disc is placed into the drive
`mechanism, the spindle shaft is inserted into the plastic
`hub which is equipped with a plastic spring which jams
`the spindle shaft into a serni-V shaped corner, securing
`the disc in position .
`
`DISC
`
`Fig. 15 is a block diagram of the viewer's tracking
`error correction system. This system compensates
`only for the tracking error, not disc eccentricity. The
`tracking position where the RF output is at a maximum
`is detected and the microprocessor gu~erning the step
`motor maintains the head in this position.
`The playback signal is a repetition of a 262 .5H
`field signal. In order to turn this signal into a standard
`TV signal, a 0.5H delay line is inserted in every other
`field and compensated . When a single field signal is
`continuously
`reproduced,
`the vertical resolution
`is
`less than original signal. In order to improve the vertical
`resolution , therefore, every other field is interpolated.
`
`DISC
`
`SPINDLE MOTOR
`
`"' SPINDLE SHAFT
`
`Fig. 15 Block diagram of tracking error correction system
`
`SEMI-V SHAPED CORNER
`
`SPRING
`
`Fig. 13 Minimization of eccentricity
`
`4 THE PLAYBACK UNIT
`Fig. 14 shows the playback unit which , when a re(cid:173)
`corded disc is inserted , converts the signals recorded on
`the disc into a viewable picture. The viewer's drive unit is
`similar to that of the camera, but the viewer's playback
`head can move both toward the outside of the disc as
`well as back toward the center so that the pictures
`can be viewed in any sequence.
`
`As the playback chrominance signal is the line(cid:173)
`sequential color-difference signal, it is synchronized by
`the delay line . Because vertical resolution becomes
`half of the original signal, as with the luminance
`signal , the chrorninance signal is interpolated by the
`circuit shown in Fig. 16 to smooth the contours.
`The horizontal resolution of a playback picture is
`240 TV lines, which is mainly determined by the num(cid:173)
`ber of pixels on the CCD. The recording capability of
`the magnetic disc is 350 TV lines, which means the
`disc can meet the requirement of higher resolution
`CCDs in the future .
`
`LINE..sEOUENTIAL
`COLOR·OIFFEREr-.K:E
`SIGNAL
`
`Fig. 14 Playback unit
`
`Fig. 16 Block diagram of process circuit of chrominance
`signal
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`330
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`IEEE Transactions on Consumer Electronics, Vol. CE-28, No. 3, August 1982
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`Fig. 18 shows the initial output waveform and the
`output waveform after 24 hours when a guide plate
`is installed. The output waveform after 24 hours is
`almost similar to that of beginning, that indicates the
`disc is not damaged.
`
`5 CONCLUSION
`
`The key technology responsible for the successful
`development of the electronic still camera includes the
`ceo imager, high density magnetic recording, its drive
`mechanism , and recording circuitry .
`This electronic still camera has many advantages
`over the conventional film camera. Its pictures can be
`viewed on a TV screen immediately, and its video signals
`can be transmitted to a distant place over a telephone
`line. Because of this speed factor , the electronic still
`camera system will be widely used by the press and
`broadcasting stations.
`rapid progress of semiconductor
`Through
`the
`technology, the ceo imager will be improved signifi(cid:173)
`cantly so as to enhance the picture quality .
`The electronic still camera will create new markets
`not only in the consumer field but also in the institu(cid:173)
`tional field , because numerous innovative applications
`are possible.
`
`ACKNOWLEDGEMENTS
`The authors wish to thank Sony Magnetic Products,
`Inc. for their development of the magnetic sheet disc
`and recording head without which the electronic still
`camera would not have come into being. The authors
`would also like to extend sincere and deep appreciation
`to other Sony people for their direct and indirect
`assistance .
`
`REFERENCES
`(1) USP 4163256, File 1972.6.27
`(2) Modem Photography, April 1980
`(3) I. Kajino, M. Shimada , Y. Nakada , Y. Hirata and
`Y. Hagiwara , "Single Chip Color Camera Using
`Narrow Channel CCD
`Imager with Over-flow
`Drain," in Tech. Papers , Symp. TEBS76-6, Insti(cid:173)
`tute of Television Engineers of Japan , pp31 - 36,
`December 16, 1981
`
`In order to minimize the level-off of playback out(cid:173)
`put when the same track is played back for many hours,
`the contact pressure also must be minimized. And
`to do this, another guide plate (See Fig. 4) is required
`in the disc drive of the playback unit to stabilize the
`disc-to-head contact. The effect of this is shown in
`Fig. 17, which shows that after 24 hours output had
`declined less than 1dB, an acceptable value.
`
`HOUR
`
`10
`
`(H)
`
`20
`
`----
`
`----
`
`_J w
`> w
`...J +I
`1-
`:::> 0
`a..
`~ -1
`0
`Cl -2
`<t w -3
`I
`
`(dB)
`
`Fig. 17 Head output fluctuations in prolonged tracing
`
`BEGINNING
`
`AFTER 24 HOURS
`
`Fig. 18 Output wave form of 24 hours tracing
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`Kihara, Nakamura, Saito, Kambara: The Electronic Still Camera A New Concept in Photography
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`331
`
`BIOGRAPHY
`
`Nobutoshi Kihara, Senior Managing Director of
`Sony Corporation and General Manager of the Develop(cid:173)
`ment Center, graduated in Mechanical Engineering from
`Waseda University in 1947. He is a senior member of
`IEEE. He has published a number of books on VTRs
`for educational and professional engineering purposes
`and has published papers in "The Journal of SMPTE",
`"ITEJ" , "The Technical Review of E.B .U ." and "Elec(cid:173)
`tronics". Mr . Kihara holds more than 200 patents
`and was one of the first recipients of the Eduard Rhein
`Prize .
`
`Keiichi Nakamura, Director , Semiconductor Divi(cid:173)
`sion, Sony Corporation , Tokyo. Graduated from Tokyo
`University (physics department), 1951. Entered NHK
`Technical Research Lab., 1951. Entered Sony Corpo(cid:173)
`ration (Semiconductor Div.), 1958. Received Ph. D.
`from the Engineering Dept., Tokyo University.
`
`Etsuro Saito, Manager of the Advanced Engineering
`Division , Development Center, Sony Corporation ,
`received his B.S. degree in Mechanical Engineering from
`Kyushu University in 1965. He joined Sony Corpora(cid:173)
`tion in 1968 and has been engaged in the development
`of a variety of video systems . Holds 40 patents.
`
`Masahiro Kambara, Manager of the Advanced
`Engineering Division , Development Center, Sony Corpo(cid:173)
`ration, received his B.S. degree in Electronic Engineering
`from Tokyo University in 1968. He joined Sony Corpo(cid:173)
`ration in 1968 and has been engaged in the design and
`development of various video systems.
`
`N. Kihara
`
`K. Nakamura
`
`E. Saito
`
`M. Kambara
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`Ex. GOOG 1021