JPH0289230A - Recording/reproducing device based upon charged image - Google Patents

Abstract

PURPOSE:To record an information signal with high density by forming at least one of a optical member and a recording medium on a face rectangular to the advancing direction of a laser beam like a rugged shape having a previously fixed pitch. CONSTITUTION:Although recording light flux made incident upon the optical member is absorbed by a photoconductive layer member PCEws having a wavelength/light absorbing characteristic, incident control light flux 47 is transmitted through a transparent substrate 27 and a transparent electrode Etw constituting the optical member, made incident upon an insulating layer IL of the recording medium, reflected by an electrode Epg, and outputted as reflected light 47r. The insulating layer ILpg and the electrode Epg are formed on the recording medium as rugged shapes at the previously fixed pitch (equal to the track pitch of recording tracks formed on the recording medium) on the face rectangular to the advancing direction of the light flux 47. Thereby, focus control information and tracking control information are generated at both of recording and reproducing operation. Consequently, high density recording can be attained.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a recording/reproducing device, and particularly to a recording/reproducing device using a charge image that can record/reproduce information signals at a high recording density. (Prior Art) As the demand for recording various information signals at high recording densities has increased, in recent years, recording media created based on various structural principles and operating principles have been used to record information signals. As is well known, high-density recording and reproduction of data has started to take place. For example, an information signal is recorded by forming unevenness in accordance with information No. 48 on the signal surface of a recording medium, and the recorded information 48
Recording and reproducing devices that reproduce signals by optical means or by detecting changes in capacitance are already in practical use for recording and reproducing video and audio signals. In order to meet the demands for high-density recording and reproduction in various technical fields, the recording layer of the recording medium is irradiated with a recording beam whose intensity is modulated by the information signal. Research has also begun on recording media that allow information signals to be recorded by causing physical or chemical changes. In recent years, as semiconductor lasers that operate stably have become easily available, various optical discs that use laser light for high-density recording and reproduction have already been put into practical use, or are on the verge of being put into practical use. It is well known that research and development is currently underway. In other words, recorded optical discs (playback-only optical discs), which are reproduced in a large violet form from a master disc on which information signals are recorded using bits formed as geometrical concave or convex parts, are, for example, video discs or compact discs. In addition to the fact that it is beginning to become popular in ordinary households as a
Optical discs that allow the user to record data only once (write-once optical discs) and erasable optical discs are being actively researched and developed for practical use in office file memories and other uses. Even as recordable optical discs or erasable optical discs,
When classified based on the physical change in the recording layer in which information signals are recorded due to the heating action of the laser beam spot, there are two types: pit-forming type, bubble-forming type, and uneven-forming type. Various formats have been proposed, such as magneto-optical type, phase change type (thermal transformation type in which light transmittance, reflectance, absorption rate, etc. change due to thermal energy), and recording type. Many proposals have been made regarding recording media in which the reproducing operation is performed using energy other than light, and various proposals have also been made regarding recording and reproducing apparatuses using these recording media. In the above-mentioned conventional main recording/reproducing apparatus using various recording media, the configuration of the apparatus for performing high-density recording is complicated, and
In addition, as mentioned above, erasable recording media have been proposed in the past, but in the case of magnetic recording media, for example, erasing is easy.
There is a problem in high-density recording, for example, in the case of optical discs, high-density recording is easy, but there is a problem in that erasing cannot be performed by simple means. In order to solve the above problem, the applicant company has developed a transparent electrode into which the laser beam is incident, a photoconductive layer member into which the laser beam which has passed through the transparent electrode is incident, and a transparent electrode which is connected to the transparent electrode. A recording medium comprising an electrode for forming an electric field therebetween, and a charge retention layer retaining charges generated in response to the electric field between the photoconductive layer member and the electrode. i Changing the electric field between the photoconductive layer member and the electrode according to the information signal to be recorded, thereby producing an information signal to be recorded on the charge retention layer member in the recording medium. means for generating a charge pattern corresponding to;
Recording and reproduction using a charge image, comprising means for reading out a charge pattern held in a charge retention layer member in the above-mentioned recording medium based on a potential difference between the surface on which the charge pattern is formed and the above-mentioned electrode. provided the equipment. FIG. 9 is a block diagram showing an example of the configuration of the above-mentioned charge image recording/reproducing apparatus. In FIG. The recording medium shown in the figure has a laminated structure of an insulating layer IL functioning as a charge retention layer member and an electrode E. The insulating layer IL described above is made using a material (for example, silicone resin) that has an extremely high insulation resistance value that can hold the charges attached thereon for a long time. This recording medium tray is rotated at a predetermined number of rotations by a rotation drive mechanism (not shown). In Figure 9, WA
is a recording system configured such that a laser beam whose intensity is modulated by the information signal to be recorded can be emitted from the lens 7, and the recording system W in the illustrated example is
A is a laser light source 1, a lens 2. Polarizer 3, optical modulator 4.
Information signal source 5, analyzer 6, which is the object of recording. RA in FIG. 9 represents information recorded in the form of a charge image on a recording medium (, -
This is a reproduction system in which No. 1 is read out using a laser beam and outputted as an electric signal, and in the example shown in Figure 9,
Laser light source 2, lens 9, 1.2.15. polarizer 10,
Beam splitter 11, wave plate 1:3, analyzer 14, photoelectric converter 16. It is composed of an amplifier 17, an output terminal 18, and the like. The laser beam emitted from the lens 7 of the recording system WA described in j■i passes through the transparent electrode Etw and passes through the photoconductor layer 1).
Given to CE. Since voltage is applied from the power source Vw between the transparent electrode EtW and the recording medium,
As mentioned above, when the laser beam whose intensity is modulated by the information (1) from the recording system WA is incident on the photoconductor layer PCE, the electricity of the portion of the photoconductor layer PCE to which the laser beam is applied is The resistance value decreases, and a discharge occurs between the insulating layer IL of the recording medium and the insulating layer IL of the recording medium at that point, and as a result, a charge corresponding to the information signal is attached to the surface of the insulating layer IL of the recording medium. The charge image corresponding to the signal is reproduced by a reproduction system as follows: a dielectric mirror DMI, a light modulating material layer PML made of a material such as lithium niobate single crystal, and a transparent The light modulating material layer PML in the detection head constituted by the electrode Etr changes the polarization plane of light passing through it by an electric field caused by a charge image attached to the surface of the insulating layer IL of the recording medium. , the laser beam emitted from the lens 12 of the reproduction system RA passes through the light modulating material layer PML and then passes through the dielectric mirror D.
The light that is reflected by the ML and enters the lens 12 again is:
The plane of polarization changes in correspondence with the charge image attached to the surface of the insulating layer TL of the recording medium described above. The light incident on the lens 12 as described above, that is, the light whose polarization plane has changed corresponding to the charge image attached to the surface of the eIIL (insulating material of the recording medium), is transmitted to the beam splitter 11 and the wavelength plate 13. As a result, the analyzer 14 emits light whose amount changes in accordance with the change in the plane of polarization of the light incident thereon, and the light is focused by the lens 15. and is applied to the photoelectric converter 16, where it is photoelectrically converted. Photoelectric converter 1
The output signal of No. 6 is amplified by the amplifier 17, so that the original information A:1 is output from the output terminal 18 in the reproduction system. By the way, in the above-mentioned charge image recording and reproducing device, by using a laser beam with a sufficiently small diameter, it is possible to easily record and reproduce information from a recording medium recorded at a high recording density with a simple device. However, in order to successfully reproduce recorded contents recorded at high recording density, it is necessary to drive and displace the reproduction element under tracking control. We previously proposed a playback device as shown in FIG. FIG. 1O is a block diagram of a previously proposed charge image reproducing device in which a tracking control method is applied to a reproducing element in a charge image recording reproducing device, and FIG. 11 is a block diagram of a tracking control system. In FIG. 10, D is a recording medium (in the following explanation, when the recording medium is a recording medium disk, it is expressed as tAV as ``recording medium''), and is shown in FIG. 10. Similar to the recording medium described above with reference to FIG.
This recording medium (1) is of a laminated structure with iE and is rotated at a predetermined rotational speed by a rotary drive end (not shown). WA in FIG. 1O is a laser light source 1, a lens 2. Polarizer 3, optical modulator 4
, Information targeted for recording (a9 source 5, analyzer 6,
The recording system is composed of a lens 7, from which a laser beam whose intensity is modulated according to the information signal to be recorded is emitted. RA in FIG. 10 is a reproducing system that uses a laser beam to read out an information signal recorded in the form of a charge image on a recording medium and outputs it as an electric signal. Lenses 9, 12, 15, polarizer 10, beam splitter 11, wave plate 13, analyzer 14, output terminal 18.
It is composed of a split photodetector PD having a photoelectric conversion element P Da = P D d, a phase compensation circuit PC, a tracking control circuit TSC, an actuator ACT, and the like. The laser beam emitted from the lens 7 of the recording system WA passes through the transparent electrode Etw and is applied to the photoconductor layer pcE, but there is an electric current @Vw between the transparent electrode Etw and the recording medium. Since the voltage is applied, when the laser beam whose intensity is modulated by the information signal from the recording system WA is incident on the photoconductor layer PCE as described above, the laser beam in the photoconductor layer PCE is applied. The electric resistance value of the exposed portion decreases, and a discharge occurs between that portion and the insulating layer IL of the recording medium, which causes the recording medium to lose its MP! A charge corresponding to the information signal is attached to the surface of the jIL, and the information to be recorded (No. 4 is recorded as a charge image.The information signal to be recorded as described above) The charge image corresponding to is reproduced by a reproduction system as follows: a dielectric mirror DMT, a light modulating material layer PML made of a material such as lithium niobate single crystal, and a transparent electrode Etr. The light modulating material layer PML in the detection head configured by changes the polarization plane of light passing through it by the electric field caused by the charge image attached to the surface 1nf of the insulating layer IL of the recording medium. Playback RA
The laser beam emitted from the lens 12 is transmitted to the light modulating material layer P.
After passing through M L, the light is reflected by dielectric mirror D M L and enters the lens 12 again. The plane of polarization changes corresponding to the charge image attached to the surface of the insulating layer IL of the recording medium described above. The light incident on the lens 12 as described above, that is, the light whose 1,1 light is changed in correspondence with the charge image attached to the surface of the insulating layer IL of the recording medium, is transmitted to the beam splitter 11. By supplying the light to the analyzer 14 via the wavelength plate 13, the analyzer 14 emits light whose intensity changes in accordance with the change in the polarization plane of the light incident on it. is focused by the lens 15 to the photoelectric conversion element P D
tx -P Dd is supplied to a split photodetector PD. As shown in FIG. 11, the four photoelectric conversion elements P D a constituting the above-mentioned split type photodetector PD
- Output from P D d g-S a ” The output signal Sa from the conversion element PDa and the output signal Sc from the photoelectric conversion element PDc are output from the adder in the tracking control signal generation circuit TSC. 19, and the four photoelectric conversion elements P r, ) a - P D constituting the above-mentioned split-type photodetector I) D
The output signal sb from the photoelectric conversion element PDb in the output signal S a −S d from the photoelectric conversion element 1)
l) The output signal Sd from d is added by the adder 20 in the tracking control signal generation circuit TSC. The output signal (Sa+Sc) from the adder 19 described above,
111 Output signal from adder 20 (Sb+Sd)
is added by the adder 21, and from the adder 21, it is sent to the output terminal 18 as (Sa+S b + S c + Sd
) is transmitted. Further, the output signal from the adder 19 described above (Sii + Sc) and the output signal from the adder 20 described above (sb+S
d) means ((Sa + 5c) (sb
15d)) is performed, and the output signal from the subtraction circuit 22 is phase-compensated in the phase compensation circuit PC and made into a tracking control signal, which is supplied from the output terminal 23 to the actuator ACT. The element is driven and displaced in a direction perpendicular to the extending direction of the recorded trace for tracking control. (Problems to be Solved by the Invention) In the charge image reproducing apparatus of the previously described charge image shown in FIG. 10, the insulating layer I1. of the recording medium I]. A tracking control signal is generated based on the reproduction signal obtained by generating an information signal recorded as a charge image on the surface of Since the drive displacement is performed in the direction perpendicular to the direction in which the recording trace extends, information signals recorded at a high recording density can be reproduced well.・
, I couldn't do it. (Means for Solving the Problems) The present invention provides a transparent electrode onto which a laser beam is incident. +) Transparent i7 written ゛rI! The laser beam that has passed through the +i is incident on the +fu of the optical j'AI F4, which is configured to include the optical member 4' and the transparent 'electrode' in the optical member marked +'ji. It is equipped with an electrode for forming an electric current W, and also holds a charge generated in response to an electric current between the photoconductive layer member of the optical member and the electric current W (! The TiC field between the recording medium containing the f-retention layer member and the photoconductor electrode described above is changed in accordance with the information signal to be recorded. U) Information to be recorded on the charge retention layer member of the recording medium (, ()) A hand that generates a charge image corresponding to the number and a charge image retained on the charge retention layer member of the recording medium described above. a light modulating material layer member that generates light in which the state of the polarization plane of readout light changes in response to the electric field intensity; In the recording and reproducing apparatus using the 11-process image, which is equipped with means for photoelectrically converting the generated electric charge image and generating the desired electric charge image, the optical member described in +'+ii and the recording apparatus are provided. At least one of the constituent members of the medium is made into an uneven shape at a predetermined pitch with respect to a plane perpendicular to the traveling direction of the laser beam. A recording and reproducing device 1L using a charge image that can generate control information, a transparent electrode where the laser beam is transmitted (1), and the light into which the laser beam passes through the above-mentioned transparent IC. An optical member formed by combining a conductive glass member and a transparent f in the optical member described above.
The photoconductive layer member of the light 21 member is provided with an electrode for forming an electric current W between it and the fi rod, and the photoconductive layer member of the optical 21 member described in 111f is the electric current between the above electric current) ÷ and ]・1 corresponding , the electric field between the photoconductive λli member described in 11;j and the above-mentioned electrode is recorded, and the information 411 is recorded. 11! in the recording medium; A light modulating material layer member that generates light in which the state of the polarization plane of the readout light changes in response to the electric field intensity due to the charge image held in the charge retention layer member, and the change in the polarization plane of the readout light described above. It is equipped with a means for generating light whose amount changes according to and then photoelectrically converting it to generate an electric signal corresponding to a charge image, and at least one of the constituent members of the optical member and the recording medium described above. Recording using a charge image in which an object is made uneven at a predetermined pitch on a plane perpendicular to the direction of travel of the laser beam, so that information for focus control and information for tracking control can be generated during recording and reproducing operations. . In the reproducing device, light having different wavelengths is used as the recording/reproducing light and the light for focus control information and tracking control information, and wavelength selection is applied to at least one of the constituent members of the optical member and the recording medium. Let's have sex. Focus control information and tracking control information are transmitted to the light for focus control information and tracking control information by a concavo-convex portion having a predetermined pitch formed on at least one of the above-mentioned optical member and a constituent member of a recording medium. 11) A main device is provided. (Example) Hereinafter, with reference to the accompanying drawings, recording by charge image of the present invention,
The specific contents of the playback device will be explained in detail. Figures 1 and 5 are diagrams for explaining the main recording/recording operations in a recording and reproducing apparatus using charge images according to the present invention, and Figure 6 is a diagram for explaining recording and reproducing operations using charge images according to the present invention. A block diagram showing an example of the structure of an optical system used in a reproducing device, and FIGS. 7 and 8 are curve diagrams showing examples of characteristics of some of the constituent parts. In FIG. 1, 24 is a transparent substrate made of glass or plastic, 25 is a recording medium substrate,
Etw is a transparent electrode, pcEpg is a photoconductive layer member, DME, pg is a dielectric mirror, II is an insulating layer used as a charge retention layer member, E is an electrode, and 25 is a substrate of a recording medium. , Vw is a power supply, and 44 is a recording light beam whose intensity is modulated by the information signal to be recorded.
44r is the recording laser beam 44 described above.
is the reflected light reflected by the dielectric mirror 1'l M L II g. In FIG. 1, what are the photoconductive layer member pcEpg and the dielectric mirror DMLρg in an optical member in which a transparent electrode Etw, a photoconductive layer member PCEpg, and a dielectric mirror DMLpg are sequentially laminated on a transparent substrate 24? , the uneven shape is formed at a predetermined pitch (a pitch equal to the recording trace (1) I-rack pitch to be formed on the recording medium) with respect to a plane perpendicular to the traveling direction of the recording light beam 44 incident on the optical member. It is designed so that information for focus control and information for tracking control can be generated during recording operation. That is, the dielectric mirror D shown in FIG.
The M Lρg has a concave and convex shape that can perform a tracking control groove similar to a tracking control groove formed on the surface of a substrate in a so-called pregreaped optical disk. ! , a transparent electrode 1 < 1 on a transparent substrate 24 shown in FIG. W and photoconductive layer member PCEp
The recording light beam 44 incident from an optical head (not shown) on the optical H'ili material constituted by sequentially stacking the dielectric mirror L) MT and ρ- is the aforementioned recording light beam. The +l tH body mirror 1) M L I) g has an uneven shape with a predetermined pitch on a plane perpendicular to the traveling direction of the optical head 44 and is reflected by the optical head as reflected light 44r as shown by the dotted line in the figure. The reflected light 44r returning toward the dielectric mirror D M
This is because it includes tracking control information generated by the uneven shape in L (2) and focus control information generated according to the distance from the objective lens to the reflecting surface in the optical head (not shown). In the optical hand, the above-mentioned reflected light 4 is generated by hand IQ similar to that used to generate tracking control information and focus control information from the reflected light from the pre-grip optical disc.
Tracking control information and focus control information are generated from 4r, and the optical spatula is displaced by one drive by an actuator so that the recording light beam 44 is brought into a good focus state and a good tracking state. In the embodiment shown in the first figure, since the focal position of the recording light beam is at the position h1 of the dielectric mirror DMLpg in the optical member, the diameter of the light spot at the position of the transparent mold 14Etw is Although the diameter of the light spot at the position of the dielectric mirror DMLpg is different from the diameter of the light spot at the position of the dielectric mirror DMLpg, the height of the photoconductive layer member PCEpg existing between the transparent type J4Etw and the dielectric mirror DMLpg is very thin. , the difference in the diameter of the light spot at the two positions described above is negligible and does not pose any problem. The surface of the insulating layer IL in the recording medium having a laminated structure with the layer IL is opposed to the surface of the dielectric mirror DM[, pg in the optical member described above, and the surface of the dielectric mirror DM[, pg in the optical member described above is opposed to the surface of the dielectric mirror DM[, pg] in the optical member described above during recording operation. Since a constant pressure is supplied from the power source Vw between the transparent electrode Ejw in the recording head (recording head) and the tripole E in the recording medium, the laser beam 44 whose intensity is modulated by the information signal as described above is optically incident on the photoconductor layer PCEPg in the member, the photoconductor layer P
When the electrical resistance value of the part where the laser beam is incident at CEp g decreases, a discharge occurs between that part and the insulating layer IL of the recording medium, and as a result, the surface of the insulating layer IL of the recording medium responds to the information signal. A charge image is formed. In this way, the insulating layer IL used as the charge retention layer member of the recording medium in the embodiment shown in the first figure is an optical member on which the laser beam 44 whose intensity is modulated by the information signal is incident during the recording operation. Photoconductor layer PCE in
As the electric resistance value of the part to which the laser beam of pg is applied decreases, a charge image is formed by the discharge generated between the part and the insulating layer IL of the recording medium, and on the other hand, as described above, the optical member Photoconductive layer member 1) CI>9
The recording light beam 44 that is incident on the dielectric mirror D M L Pg and the dielectric mirror D M L Pg during recording is arranged at a predetermined pitch (equal to the track pitch of the recording marks to be formed on the recording medium) in a plane perpendicular to its traveling direction. The reflected light 44r is reflected by the dielectric mirrors DM1, -pg, which have concave and convex shapes at a pitch (pitch), but this reflected light 44r is used to generate tracking control information by a pre-group in the case of a well-known bri-groove optical disc. Through a process similar to that of the dielectric mirror [11MLpg], the tracking control information is included based on the presence of the uneven shape in MLpg, and the reflected light 4 is
4r. contains focus control information generated according to the distance from the objective lens to the reflection area in the optical head (not shown), so the racking control information is obtained from the reflected light from the brigrooved optical disk. Tracking control information and focus control information can be generated from the reflected light 44r by providing a means similar to the "F stage" in an optical head (not shown), which is used to generate the above-mentioned reflected light 44r. By supplying it to an automatic tracking control system and an automatic focus control system so that the optical head is driven and displaced by the actuators in the two automatic control systems described above, -11:I is obtained. 114 can perform the described operation under a good focus-controlled energizer and a good tracking control state.As described above, the so-called brigroove is created by the concavo-convex pattern sunk into the optical member during the recording operation. The reproduction operation of the information signal from the recording medium in which the recording operation is performed under dragging control and focus control and a charge image corresponding to the information signal is formed on the charge retention layer member as in the case of an optical disk is performed, for example, in the fifth step. In FIG. 5, a recording medium consisting of a substrate 25, an electrode E, and an insulating layer 6!j acting as a retaining layer member has the same structure as described above with reference to FIG. Information signals are recorded by forming a charge image according to a record 8!l!Ij.The insulating layer r in the recording medium

[, dielectric mirror DML, light modulating material layer member PML, and transparent electrode E t r
The substrate 26 is used as necessary and constitutes an optical charge image reading head. Reference numeral 45 represents a reading laser beam incident on the reading head, and 45r represents reflected light reflected by the dielectric mirror DML in the reading head. The charge image on the insulating layer IL of the recording medium is generated as optical information +lj in the reading head shown in FIG. 5 in the following manner. That is, a dielectric mirror DML and a light modulating material layer P made of a material such as lithium niobate single crystal.
The light modulating material layer PMI in the reading head constituted by the ML and the transparent electrode Etr is caused by an electric field caused by a charge image attached to the surface of the insulating layer IL of the recording medium.
Since the polarization plane of the light passing through it is changed, the reading laser beam 45 emitted from the optical head passes through the light modulating material layer 1) M L and then passes through the *111 body mirror DML.
The reflected light beam 45r that is reflected by the recording medium and enters the optical head again has a polarization plane that has changed in correspondence with the charge image attached to the surface of the insulating layer IL of the recording medium. Therefore, the reflected light 45r emitted from the reading head in the above manner is, for example, 111 shown in FIG. 1O.
If the light 45r is made to enter the lens 12 of the live system RA, the light 45r will be supplied to the analyzer 14 via the beam splitter 11 and the wave plate 13, and from the analyzer 14, the polarized light in the light that has entered it will be Light whose scene changes in response to changes in the surface is emitted, is focused by a lens 15, and is supplied to a split photodetector 1) D having photoelectric conversion probes PDa to PDd. be done. As shown in FIG. 11, the four photoelectric conversion probes P
) a - Output from P D d (Output signal Sa from photoelectric conversion element PDa in No. 11 5d-8d and output signal +j' S from photoelectric conversion element PDc are tracking control signal generation circuit 'I' The four photoelectric conversion elements P constituting the divided photodetector PD are added by the adder 19 which adds r to SC, and are also marked +'+Ff.
Output signal S a − from D a ” P l) d
Output from photoelectric conversion probe PDb toward S d, 1
No. sb and output from photoelectric conversion element P I) d (i No. S (I means 1) Ranking control signal generation circuit 'I'
They are added by adding 11 A:12 Q in S C. Output No. 4if (Sa+Sc) from the adder 19 described above
The output from the adder 8 20 described above (No. 1d (Sb+S
d) is added by the adder 21, and the reproduced signal (Sa+Sb+Sc+Sd) is sent to the output terminal 18 from the adder 21. Further, the output signal from the adder 19 described above (Sa + S (
:) and the output from the adder 20 described above -(Sb+S
d) means ((Sa+5c)−(S
b+5d)) is performed, and the output signal from the subtraction circuit 22 is phase-compensated in the phase compensation circuit PC, and is made into a tracking control signal, which is supplied from the output terminal 2a to the actuator ACT, and the above-mentioned actuator ACT The reading head is driven and displaced in a direction perpendicular to the extending direction of the recording trace for tracking control. Further, the signal for automatic focus control is transmitted from the lens 15 to the photoelectric conversion elements 1-3 [ ) The light flux given to il~PDd is divided and passed through a cylindrical lens and a knife lens to become light 'i for automatic focusing.
By supplying it to the i converter, it can be obtained as the output (g i) of the photoelectric converter, so the signal for automatic focus control obtained as a blind beam is supplied to the actuator 8CT. The above-mentioned actuator A
C"I" allows the reading head to be displaced in the direction perpendicular to the surface of the recording medium for focus control. Next, in the embodiment shown in FIG. 2, 27 is a transparent substrate made of glass or plastic, etc.
w is a transparent electrode, P CE w s is a photoconductive layer portion tJ, I
L, pg are insulating layers used as charge retention layer members, E
pg is the r#i pole, 28 is the recording medium substrate, Vw is the power supply,
46 is a recording light beam (recording laser beam) whose intensity is modulated by the information signal to be recorded; 47 is a control light beam for generating tracking control information and focus control information; 47 r is a control light beam; The control light beam 47 described above is the reflected light reflected by the electrode EPg. In FIG. 2, the optical member constructed by sequentially laminating a transparent electrode Etw and a photoconductive layer member PCEws on a transparent substrate 27 is a member that operates as a recording head.
Photoconductive layer member P CE w s in the above-mentioned optical member
As the material, a material having wavelength versus light absorption characteristics as illustrated in FIG. 7 or FIG. 8 is used. 11; If the photoconductive layer member PCEws described in I is used, for example, as the photoconductive layer member PCEws having wavelength versus light absorption characteristics as illustrated in FIG. The control light beam 47 is in a wavelength region shorter than the wavelength of the laser beam of the recording light beam 46, for example, 580 nm, 680 nm, 7
Laser light with a wavelength such as 80 nm or 880 nm
Also, use a laser beam with a wavelength longer than nm. If the photoconductive layer member P CE ws described above has a wavelength versus light absorption characteristic as illustrated in FIG. Laser beams having wavelengths of 680 nm and 780 nm are used, and as the control beam 47, a laser beam having a wavelength of around 8:30 nm, which is longer than the wavelength of the laser beam of the recording beam described above, is used. A recording light beam 46 that enters an optical member that operates as a recording head from an optical head (not shown) in FIG. Photoconductive layer member PCEw having
However, the control light beam 47 that enters the optical member from an optical head (not shown) is transmitted through the transparent substrate 27, the transparent electrode Etw, and the photoconductive layer member PCEws that constitute the optical member. In the recording medium, the light enters the insulating layer IL that acts as a charge retention layer, passes through it, and is reflected by the electrode Epg to become reflected light 47r, which then acts as a recording head again. The light passes through the optical member that performs the process and returns to the optical head (not shown). The insulating layer I L p and the electrode Epg in the recording medium shown in the second illustrated embodiment are perpendicular to the traveling direction of the control light beam 4'7 incident on the recording medium as described above. The surface has an uneven shape at a predetermined pitch (pinch equal to the track pitch of the recording trace to be formed on the recording medium), and is used for focus control both during recording operation and during playback operation (described later). information and tracking control information. That is, the insulating layer iLpg and the electrode Epg shown in FIG. 2 (the same applies to FIG. 3) are grooves for tracking control formed on the surface of the substrate in the so-called Zino Group 1 optical disk. The insulating layer I in the recording member shown in FIG. 2 (the same applies to FIG.
A control light beam 47 is incident on Lpg and electrode Ep from an optical head (not shown) via an optical member.
) Reflected light 47r returns to the optical head as reflected light 47r after being reflected by the electrode Epg, which has a concave and convex shape with a predetermined pitch, perpendicular to the traveling direction of the control light beam 47. The electrode E is generated by a process similar to that in which the tracking control information is generated by the pre-groove in the case of the well-known pre-groove optical disc.
It is in a state that includes tracking control information based on the presence of uneven shapes in pg, and
Since the reflected light 47r in 1'Iif includes focus control information generated in accordance with the distance from the objective lens to the reflective surface in the optical head (not shown), By providing the optical spatula 1- (not shown) with a means similar to the means used to generate tracking control information and focus control information from reflected light, 1111
Tracking control information and focus control information are generated from the reflected light 47r and supplied to an automatic tracking control system and an automatic focus control system, so that the optical head is driven and displaced by the actuators in the two automatic control systems described above. By doing so, it is possible to perform the recording operation under the above-mentioned recording light beam 46 under a good focus control state and a good tracking control state. Further, in the embodiment shown in the second figure, the surface of the photoconductive layer member PCEws in the optical member described above is formed by laminating the substrate 28, the electrode Epg, and the insulating layer I Lpg that acts as a charge retention member in the recording medium. A constant voltage is supplied from a power source Vw between the transparent electrode Etw in the optical member and the electrode Epg in the recording medium during recording operation. Therefore, as shown in iLt, the laser beam 46 whose intensity is modulated by the information signal is incident on the photoconductor layer PCEwS in the optical member, and the portion of the photoconductor M4PCEws where the laser beam is given is When the electric resistance value of d becomes low, a discharge occurs between the VQM layer ILpg of the recording medium in that part, and a charge image corresponding to the insulating layer 1 of the recording medium [, information signal on the surface of pg] is generated. is formed. In addition, in practice, it is not necessary to cause the position of the light spot by the recording light beam 46 and the position of the light spot by the control light beam 47 to be on the same recording trace. Furthermore, since the reflective surface of the recording light beam 46 and the reflective surface of the control light beam 47 are shifted from each other with respect to the traveling direction of the light beam, when the respective focal planes of the two light beams 46 and 47 described above are the same, In this case, the diameters of the two light spots due to the two luminous fluxes 46° 47 described above are different from each other, but the difference in diameter is negligible and does not pose a problem. In addition, in order to compensate for the aforementioned diameter deviation i1E, 1);
Of course, the focal planes of the two light spots described above may be shifted in advance. As shown in section 11, during the recording operation, the recording operation is performed under tracking control and focus control using the concave-convex pattern provided on the recording medium, as in the case of a so-called bri-groove optical disk, and the charge image corresponding to the information signal is retained. Reproduction of information signals from recording media formed on layered members! The 'l+ operation is performed, for example, as shown in the third diagram. 3. In FIG. 3, a recording medium consisting of a substrate 28, an electrode Epg, and an insulating layer ILpg functioning as a charge retention layer member is provided with information by forming a charge image by the recording operation as already described with reference to FIG. The signal is recorded. A dielectric mirror DML and a light modulating material layer member PMI arranged opposite to the insulating layer ILp in the recording medium,
The optical member consisting of the transparent electrode E t, r constitutes an optical charge image reading head. 48 is a reading light beam incident on the reading head. 48r is the 5, i'lt body mirror D in the read head
49 is a reflected light beam of the reading light beam 48 reflected by MI, 49 is a control light beam incident on the reading head, and 49r is a reflected light beam of the control light beam 49 reflected by the electrode Erl g on the recording medium. be. The dielectric mirror DML in the readout heel 1 shown in FIG. 3 is made to have wavelength selection characteristics such that it reflects the reading light beam 48 and transmits the control light beam 49. The charge image on the insulating layer IL of the recording medium is generated as optical information 111 in the reading head shown in FIG. 3 in the following manner. That is, a dielectric mirror DML, a light modulating material layer PML made of a material such as lithium niobate single crystal, and a transparent rF! , the luminous intensity 1 side material layer 1) in the reading head composed of Et+ and M
L changes the polarization plane of light passing through it due to the electric field caused by the charge image attached to the surface of the insulating layer I L p of the recording medium. The light beam 48 passes through the light modulating material layer PML, is reflected by the dielectric mirror DML, and is reflected by the reading light beam 48 into the optical head again.
is attached to the surface of the insulating layer ILpg of the recording medium described above.
The plane of polarization has changed corresponding to the iLt d:j image shown. Therefore, when the reflected light beam 48r of the reading light beam 48 emitted from the reading head is passed through an analyzer as described above, it is converted into light whose light intensity changes in accordance with the amount of electric charge, and then photoelectrically converted, an output signal is obtained. Obtained 9 In addition, the control light beam 49 that has passed through the reading head is incident on the recording medium, and the reflected light beam 49r of the control light beam 49 that is generated by being reflected by the electrode Epg contains tracking control information generated by the uneven shape of the electrode Epg, Since it includes focus control information generated according to the distance from the objective lens to the reflecting surface in the optical head (not shown), tracking control information and focus control information can be extracted from the reflected light from the bri-grooved optical disk. Tracking control information and focus control information can be generated from the reflected light beam 49r of the control light beam 49 by providing means similar to the means used to generate the tracking control information in the optical head (not shown). By supplying this to the automatic tracking control system and the automatic focus control system so that the optical head is driven and displaced by the actuators in the two automatic control systems described above, the above-mentioned reading light beam 48 can be brought into good focus. The recording operation can be performed under a control state and a good 1-ranking control state. When the constitutive members of the recording medium are provided with concavities and convexities for tracking control in this manner, they can be used both during recording and reproducing operations, so that stable control operations can be performed. Further, linearly polarized light is used as reading light, and circularly polarized light is used as control light. Next, in FIG. 4, 26 is a transparent 1□ (plate) made of glass or plastic; 30 is a transparent auxiliary substrate made of glass or plastic; Edm is a dichroic mirror electrode. t pole, P
CE p g C light 4tft JF7 member, IL is an insulating layer used as a charge retention layer member, 1 is an electrode, 25
is the substrate of the recording medium, Vw is the power supply, 50 is the recording light beam (recording laser light weight) whose intensity is changed by the information signal to be recorded, and 51 is the tracking control information and focus. A control light beam 51r is used to generate control information, and reference numeral 51r indicates that the control light beam 50 is connected to the electrode IF.
, p is the reflected light reflected by g. In FIG. 4, the auxiliary substrate 3 attached to the transparent substrate 29
0, dichroic mirror electrode 1! : The optical member constructed by sequentially laminating d T11 and photoconductive member P CE p g is a member that operates as a recording end, and in the optical member described in 1. The dichroic mirror electrode 1': dm is configured to have a characteristic of transmitting the δdψTagawa luminous flux 0 and reflecting the control luminous flux 51, and also has the property of reflecting the control luminous flux 51.
The photoconductive layer member P CE p K described in 1 is a recording light beam 5.
It is constructed as something that absorbs 0. The above-mentioned auxiliary 1 & plate 30 are arranged at a predetermined pitch (a pitch equal to the track pitch of recording traces to be formed on the recording medium) with respect to a plane perpendicular to the traveling direction of the recording light beam 50, 51 incident on the above-mentioned optical member. ), and therefore, the dichroic ink mirror' and fi pole FdIn attached to the uneven surface of the auxiliary substrate 3o also have the same uneven surface shape as the auxiliary substrate 30. It has an uneven surface shape of 1
Wakuki's dichroic mirror ttft4 E d rn
The negative surface of the photoconductive layer member 1) CEpg attached to the dichroic mirror electrode Edm has an uneven surface shape similar to the above-mentioned uneven surface shape. That is, the dichroic mirror electrode Edm shown in FIG. 4 functions similarly to the tracking control groove formed on the surface of the substrate in a so-called BRIGLEEP 1 optical disk, and has a ridge-like uneven shape. A transparent substrate 29 is shown in FIG.
and auxiliary substrate; 30, dichroic mirror electrode T
When an optical head recording light beam 50 and a control light beam 51 (not shown) are incident on an optical member constructed by sequentially laminating the photoconductive layer member PCEpg and the photoconductive layer member PCEpg,
The above-mentioned recording light beam 50 is connected to the dichroic mirror electrode E.
dm, reaches the photoconductive layer member PCEpg, and is absorbed there. However, the control light beam 51 has an uneven shape with a predetermined pitch perpendicular to the traveling direction of both the light beams 50 and 51. The light is reflected by the dichroic mirror electrode Edm and returns to the optical head as a reflected light beam 51r of the control light beam 51. The reflected light beam 51r of the control light beam 51 described above is composed of tracking control information generated by the uneven shape of the dichroic mirror electrode Edm and a focus generated according to the distance from the objective lens to the reflective surface in the optical head (not shown). Since the optical head includes control information, a means similar to the means used to generate tracking control information and focus control information from the reflected light from the bri-grooved optical disk is installed in the optical head (not shown). By providing this, tracking control information and focus control information are generated from the reflected light beam 51r of the control light beam 51 and supplied to the automatic tracking control system and the automatic focus control system, so that the optical head By driving and displacing the actuators in the two automatic control systems, the recording light beam 50 can perform the recording operation under good focus control conditions and good tracking control conditions. In the embodiment shown in the fourth figure, the surface of the insulating layer IL in the recording medium having a laminated structure of the substrate 25, the electrode E, and the insulating layer IL functioning as a charge retention member of the recording medium, and the dielectric mirror in the optical member described above. It faces the surface of the DMLpg, and during recording operation, a constant voltage is supplied from the tti source Vw between the transparent electrode Etw in the optical member (recording head) and the electrode E in the recording medium. Therefore, the laser beam 44 whose intensity is modulated by the information signal as described above enters the photoconductor layer PCEpg in the optical member, and the photoconductor layer PCEpg
When the electrical resistance value of the portion where the laser beam is incident at E p g decreases, a discharge occurs between that portion and the absolute M layer IL of the recording medium. As a result, an image 1a corresponding to the information signal is formed on the surface of the insulating layer IL of the recording medium. As mentioned above, during the recording operation, the recording operation is performed under tracking control and focus control, as in the case of a so-called bri-groove optical disk, by the concave-convex pattern sunk into the optical member, and a charge image corresponding to the information signal is formed. 1!
The 11 operation of information No. 48 from the recording medium formed on the load holding layer member can be performed in the same manner as described above with reference to FIG. 5, for example, and detailed explanation thereof will be given here. Omitted. Next, an example configuration of the optical head will be explained with reference to FIG. 5. In FIG. It emits light n·1.As the semiconductor lasers 31 and 32 described above, one configured with two or more oscillating parts in one container may be used. :33-236 is a dichroic mirror, 37 to 39 are lenses, 40 is a 174 wavelength plate, 41 is a prism, 42.
43 is a photodetector, 44 is an optical member (recording head or reading head), and p r+s is a polarizing beam splinter in which a polarizer is provided on the light transmitting and reflecting surfaces. The optical head shown in FIG. 6 includes a first laser beam emitted from one semiconductor laser; The second laser beam emitted from the other semiconductor laser: 32 has a different wavelength,
An optical head configured to perform recording operation, reading operation (+Ii production), tracking control, and focus control U'jj operation (control operation) using the two semiconductor lasers 31 and 32 described above. An example of the configuration is shown. In the optical head shown in FIG. 6, one of the f-conductor lasers 3
The first laser beam emitted from the conductor laser 32 is shown by a solid line in FIG. 1, and the light emitted from the other conductor laser 32 is shown by points v and X in the figure. Dichroic mirror 33 used in the optical head shown in FIG.
36, the dichroic mirrors 33 and 36 are of such a nature that they transmit the first laser beam and reflect the second laser beam, and the dichroic mirrors 34 and 35 transmit the second laser beam. It has a characteristic of transmitting the laser beam and reflecting the first laser beam. Now, the first laser beam emitted from the two semiconductor lasers 31 and 32 shown in 11; Among the second laser beams, if the first laser beam is used as the aforementioned control beam, and if the second laser beam is used as the recording or reading beam, the semiconductor laser 32 emits a laser beam whose intensity is modulated according to the information signal to be recorded during the recording operation, and emits a laser beam whose intensity is modulated according to the information signal targeted for recording, and during the reproduction operation (
During a read operation), a constant laser beam with a predetermined intensity is emitted, and the semiconductor laser 31 is also configured to emit a laser beam with a constant intensity. The laser light emitted from the f-conductor laser 31 passes through the optical path shown by the solid line in FIG. 6 as a control light beam and is irradiated onto the optical member 44, and the reflected light passes through the optical path shown by the solid line in the figure. The light passes through and is applied to a photodetector 42. That is, the laser light emitted from the semiconductor laser 3L passes through the dichroic mirror 33 as a control light beam, enters the polarizing beam splitter PBS, and enters the polarizing beam splitter PB.
S output as linearly polarized light and collimator lens 37
The dichroic mirror 3
4 and enters the 1/4 wavelength plate. The light emitted as circularly polarized light from the 174 wavelength plate is given to the prism 41 → dichroic mirror 35 → objective lens 38 → optical member (recording head, reading head), and the reflected light is sent to the optical member 44 → objective lens 38. → Dichroic mirror 35 → Prism 41 → Dichroic mirror 34 → Collimator lens 37 → Polarizing beam splitter P
The light passes through an optical path of BS→lens 39→dichroic mirror 36→photodetector 42 and is applied to the photodetector 42, from which a required control signal is output. Further, when the recording/reproducing device is in the recording operation mode, the information ID emitted from the semiconductor laser 32 is recorded.
The laser beam whose intensity is modulated by Katsura passes through the optical path indicated by the dotted line in FIG. 6 as a recording light beam and reaches the optical member 4.
4, and a charge image is recorded on the recording medium as described above. Recording/playback device i'? In the reproducing operation mode, a laser beam having a constant light intensity emitted from the semiconductor laser 32 passes through the optical path shown by the dotted line in FIG. 1' of the recording medium
ti (After reading the J image, the reflected light passes through the optical path indicated by the dotted line in the figure and is applied to the photodetector 4:3. In other words, when the recording and reproducing device is set to the reproducing operation mode A laser beam with a constant light intensity emitted from the semiconductor laser 32 is reflected as a reading light beam by a dichroic mirror;
It is output as linearly polarized light from the polarizing beam splitter 1.1 BS, and is made into parallel light by the collimator lens 37, and then is transmitted to the dichroic mirror 34 → dichroic mirror 35 → objective lens 38 → optical member (reading head). Also, the reflected light is given to the optical member 44
→ Objective lens 38 → Dichroic mirror 35 → Dichroic mirror 34 → Collimator lens 37 → Polarizing beam splitter PBS → Lens 39 → Dichroic mirror 36 → Pass through the optical path of photodetector 'a43 to photodetector 43
, and a reproduced signal is output from the photodetector 43. The optical head shown in FIG. 6 can be used in cases where recording, reproduction, and control are performed using two laser beams as illustrated in FIGS. 2 to 4, but the optical head shown in FIG. An optical head with a structure in which the semiconductor laser 32, 174-wave plate 40, dichroic mirror 36, and photodetector 43 are removed is reproduced as explained in connection with FIG. Pl
It can be used as an optical head during J production (reading operation). Note that the medium used for recording and reproducing information signals in the charge image recording and reproducing apparatus of the present invention may be a disk-shaped recording medium, or a tape-shaped, sheet-shaped, or card-shaped medium. Any form can be used. In addition, in the description of the embodiments so far, it has been assumed that a laminate structure consisting of electrodes, an insulating layer functioning as a charge retention layer member, and a substrate is used as a recording medium. It goes without saying that a structure in which the recording head component and the read head component shown in FIG. 5 are laminated with an electrode and a charge retention layer member may also be used. . (Effects of the Invention) The charge image recording and reproducing apparatus of the present invention includes a transparent electrode into which a laser beam is incident, and a photoconductive layer member into which the laser beam transmitted through the transparent electrode is incident. The optical member is provided with an electrode for forming an electric field between the optical member and the transparent electrode of the optical member, and corresponds to the electric field between the photoconductive layer member of the optical member and the electrode. a recording medium having a charge retention layer member that retains the charges generated by the photoconductive layer member, and changing the electric field between the photoconductive layer member and the electrode according to the information signal to be recorded; A means for generating a charge image corresponding to an information signal to be recorded on a charge retention layer member in the recording medium, and a corresponding electric field intensity due to the charge image retained in the charge retention layer member in the recording medium. a light modulating material layer member that generates light whose polarization plane is changed in readout light; and a light modulating material layer member that generates light whose appearance changes according to the change in the polarization plane of the readout light and then performs photoelectric conversion. In a charge image recording and reproducing apparatus comprising a charge image and a means for generating a corresponding electric signal, at least one of the constituent members of the optical member and the recording medium described above is arranged in the traveling direction of the laser beam. Recording using a charge image, which has an uneven shape at a predetermined pitch with respect to orthogonal objects, so that information for focus control and information for tracking control can be generated during recording and reproducing operations. A reproducing device, an optical member configured to include a transparent electrode into which a laser beam is incident, a photoconductive layer member into which a laser beam transmitted through the transparent electrode is incident, and a transparent 11 in the optical member. A charge retention layer member is provided with an electrode for forming an electric field between the photoconductive layer member of the optical member and the charge retention layer member that retains the electric charge generated in response to the electric field between the photoconductive layer member and the electrode. The electric field between the photoconductive layer member and the electrode is changed in accordance with the information signal to be recorded, so that the charge retention layer member in the recording medium is recorded. means for generating a charge image corresponding to the information signal to be read, and a state of the polarization plane of the readout light changing in accordance with the electric field intensity due to the charge image held in the charge retention layer member of the recording medium. A light modulating material layer member that generates light, and means that generates light whose scene changes depending on the change in the polarization plane of the readout light and then photoelectrically converts the light to generate an electric signal corresponding to a charge image. At least one of the constituent members of the optical member and the recording medium described above is made into an uneven shape at a predetermined pitch with respect to a plane perpendicular to the traveling direction of the laser beam, so that it can be used during recording and 11f raw operations. In a recording and reproducing device using a charge image, which is capable of generating information for focus control and information for tracking control. Lights with different wavelengths are used as recording and reproducing light and light for focus control information and ranking control information, and wavelength selection is applied to at least one of the constituent members of the optical member and recording medium described above. The above-mentioned optical section is configured with a concave-convex portion of a predetermined pinch formed in at least one of the constituent members of the recording medium, and the light for focus control information and tracking control information is provided. Since this is a charge image recording and reproducing device that generates focus control information and tracking control information, the charge image recording and reproducing device of the present invention is a charge image recording and reproducing device that is capable of crystal density recording. According to the present invention, recording and reproducing operations can be performed under stable rl!l!IJl-racking control operation and automatic focus control operation both during recording and reproducing. The above-mentioned conventional problems can be solved satisfactorily.

[Brief explanation of the drawing]

FIGS. 1 to 5 show recording by charge images of the present invention. 111 is a block diagram of a part of the configuration of the photoconductor, FIG. 6 is a block diagram of an example of the optical I\rad configuration, FIGS. 7 and 8 are diagrams of wavelength vs. light absorption characteristic curves of the photoconductor, and FIGS. FIG. 11 is a block diagram of a previously proposed device. D...recording medium, Vw...power supply, Etw, Etr...
・Transparent electrode, P CE , P CE p g , P
CI! :ws...photoconductive layer member, IL, ILp
g...Insulating layer, E, Epg... Electrode, ACT...
Actuator, WA... Recording system, RA, configured to emit from the lens 7 a laser beam whose intensity is modulated by the information signal to be recorded.
...A reproducing system that reads out information recorded in the form of a charge image on a recording medium using a laser beam and outputs it as an electric signal, PD...A split-type photodetector, PDa-
PDd...photoelectric conversion element, PC...phase compensation circuit,
AC1゛...actuator, PML...light modulating material layer member, DML, DMLI3g...dielectric mirror, E d
m-dielectric mirror electrode, PBS... polarizing beam splitter, 1.8... laser light source, 2, 7, 9, 12.15
... Lens, 3.10... Polarizer, 4... Light modulator, 5... Information signal source targeted for recording, 6,
14...Analyzer, 11...Beam splitter, 1:
3...Wave plate, 16...Photoelectric converter, 17...Amplifier, 18...Output terminal, 19-21...Adder, 2
2... Subtractor, 23... Tracking control signal output terminal, 24-29... Board, 30... Auxiliary board,
31.32...Semiconductor laser, 33-36...Dichroic mirror, 37-39...Lens, 40...
・1/4 wavelength plate, 41...prism, 42.43...
・Photodetector, 44...Optical member (recording head or reading head), Patent applicant: Japan Victor Co., Ltd. Agent: Patent attorney, Takashi Konma Seishir Exhibition (nm) - Awata procedure moss n Seyo F (Voluntary) 1. Indication of the case 1986 Patent Application No. 240296 2, Name of the invention: Recording and reproducing device by charge image 3, Person making the amendment Relationship to the case Patent address Address: Kanano name, Yokohama City, Kanagawa Prefecture (432) ) Japan Bi4, agent

Claims (1)

[Scope of Claims] 1. An optical member comprising a transparent electrode into which a laser beam is incident, a photoconductive layer member into which a laser beam transmitted through the transparent electrode is incident, and an optical member as described above; A charge holding device that is provided with an electrode for forming an electric field between the transparent electrode of the member and holds the electric charge generated in response to the electric field between the photoconductive layer member of the optical member and the electrode. A recording medium having a layer member, and recording on the charge retention layer member of the recording medium by changing the electric field between the photoconductive layer member and the electrode according to the information signal to be recorded. A means for generating a charge image corresponding to the information signal to be targeted, and a state of the polarization plane of the readout light changes in response to the electric field intensity due to the charge image held in the charge retention layer member of the recording medium. A light modulating material layer member that generates light that changes in intensity, and a light modulating material layer member that generates light whose intensity changes depending on the change in the polarization plane of the readout light that is photoelectrically converted to generate an electric signal corresponding to a charge image. In a charge image recording and reproducing apparatus, at least one of the constituent members of the optical member and the recording medium is uneven at a predetermined pitch with respect to a plane perpendicular to the traveling direction of the laser beam. A recording and reproducing device 2 using a charge image, which is shaped so that it can generate focus control information and tracking control information during recording and reproducing operations, a transparent electrode into which a laser beam is incident, and the transparent electrode described above. an optical member configured to include a photoconductive layer member into which the laser beam transmitted through the laser beam is incident; and an electrode for forming an electric field between the transparent electrode in the optical member and the above-described A recording medium having a charge retention layer member that retains charges generated in response to an electric field between the photoconductive layer member of the optical member and the electrode; means for generating a charge image corresponding to the information signal to be recorded on a charge retention layer member of the recording medium by changing an electric field according to the information signal to be recorded; and the recording medium a light modulating material layer member that generates light in which the state of the polarization plane of the readout light is changed corresponding to the electric field intensity due to the charge image held in the charge retention layer member; It is equipped with a means for generating light whose amount changes according to the change and then photoelectrically converting the light to generate an electric signal corresponding to a charge image, and at least one of the constituent members of the optical member and the recording medium described above. This is based on a charge image that is made into an uneven shape at a predetermined pitch on a plane perpendicular to the direction of travel of the laser beam, so that information for focus control and information for tracking control can be generated during recording and reproducing operations. In a recording/reproducing device, light having different wavelengths is used as the recording/reproducing light and the light for focus control information and tracking control information, and at least one of the constituent members of the optical member and the recording medium described above is used. At least one of the above-mentioned optical member and the constituent member of the recording medium is provided with wavelength selectivity.
Recording using a charge image in which focus control information and tracking control information are generated in light for focus control information and tracking control information by a concavo-convex portion having a predetermined pitch formed in one piece;
playback device