JPH0212067A - Device for generating electric signal corresponding to surface potential distribution - Google Patents

Abstract

PURPOSE:To eliminate a defect where shading is produced in corresponding to the uneven thickness of an optical modulating layer member by constituting the title device of a read head composed of the optical modulating layer member, etc., driving mechanism, photoelectric converter, memory device, subtractor, etc. CONSTITUTION:A read head Hr is constituted by laminating a transparent electrode Et, optical modulating layer member PML, and dielectric mirror DML and alternately moved and displaced to a 1st position where the mirror DML is closely faced to the surface of an object O to be inspected, and a 2nd position where the mirror DML is far faced to the surface of the object O, by means of a driving mechanism DM. The electric signal outputted from a photoelectric converter PD in corresponding to a detecting result of the surface potential at a specific part of the object O at the 1st position is stored in a one-line memory LM which is a memory device. Then, by obtaining the difference signal between the electric signal read out from the memory LM and the electric signal outputted from the converter PD in corresponding to a detecting result of the surface potential of the specific part at the 2nd position by means of a subtractor SUB, an electric signal which is not influenced by the uneven thickness of the member PML can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for generating an electrical signal corresponding to a surface potential distribution.

(Prior art) In recent years, as the demand for high-quality and high-resolution playback images has increased, so-called HD
New systems such as TV and HDTV have been proposed. In order to obtain high-quality, high-resolution reproduced images, an imaging device suitable for this purpose is required.
This is because there is a limit to miniaturizing the electron beam diameter in the image pickup tube.

It is not possible to achieve higher resolution by miniaturizing the electron beam diameter, and because the target capacity of the image pickup tube increases in proportion to the target area, it is difficult to achieve higher resolution by increasing the target area. For example, in the case of video imaging devices, as the resolution increases, the frequency band of the video signal increases from several + M) Iz to several hundred MHz or more, which causes problems in terms of S/N. For these reasons, it is difficult to generate a video signal that allows an imaging device to reproduce a high-quality, high-resolution reproduction image.

As described above, conventional imaging devices have been unable to adequately generate video signals that can reproduce high-quality, high-resolution images due to the presence of an essential image sensor for their configuration. In order to solve the above-mentioned problems, the applicant company first obtained a high-resolution optical image using an imaging device using a light-to-light conversion element, and then converted the optical image to a light-to-charge conversion element. We proposed an imaging method and a recording method that record high-resolution charge images on a recording medium having a charge storage layer.

Incidentally, a high-resolution optical image is obtained by an imaging device using the above-mentioned light-to-light conversion element, and the optical image is transferred to a high-resolution charge image on a recording medium having a charge storage layer using the light-to-charge conversion element. When implementing the imaging method and recording method by the applicant's company that records the image as an electrical signal, it is necessary to read out the charge image recorded on the recording medium as an electrical signal, and a means for doing so is required. Ta.

Therefore, in order to solve the above-mentioned problems, the applicant's company first developed a read head that was constructed by laminating a transparent electrode, a light modulating material layer member, and a dielectric mirror, and the dielectric mirror side of the read head was constructed by laminating a transparent electrode, a light modulating material layer member, and a dielectric mirror. means for placing the object in close proximity to the object to be detected having a surface potential distribution that is targeted by the above-mentioned method; a generator for generating an electrical signal corresponding to a surface potential distribution, comprising means for applying a laser beam emitted from a reading head to a photoelectric conversion element via an analyzer, a transparent electrode, a light modulating material layer member, and a dielectric mirror; means for arranging a read head constructed by stacking the above, with the dielectric mirror side of the read head in close proximity to an object to be detected having a surface potential distribution to be detected; A surface potential distribution comprising means for inputting a laser beam having a linear cross section, and means for applying the laser beam having a linear cross section emitted from the reading head to a line image sensor via an analyzer. proposed a corresponding electric signal generator.

(Problems to be Solved by the Invention) By the way, in the previously proposed electrical signal generation device corresponding to the surface potential distribution, the optical member used as one of its constituent members, that is, the For example, when an electro-optic effect crystal such as a lithium niobate single crystal is used as a light modulating material layer member that changes the state of light according to the intensity distribution of an electric field, In addition to producing birefringence when an electric field is applied to an anisotropic crystal, birefringence also occurs due to the anisotropy of the crystal even in the absence of an electric field, that is, in the initial state when the applied electric field is zero. Since the phase difference between the light ray and the extraordinary ray varies depending on the thickness of the anisotropic crystal, the unevenness in the thickness of the crystal directly becomes the unevenness in the phase difference between the ordinary ray and the extraordinary ray in the initial layer.

Therefore, when there is an uneven thickness of the light modulating material layer member in the reading head, the detection result of the surface potential of the detected object corresponds to the thickness unevenness of the light modulating material layer member used in the reading head. Since shading occurs, a solution to this problem was sought.

(Means for Solving the Problems) The present invention provides a reading head configured by laminating a transparent electrode, a light modulating material layer member, and a dielectric mirror, and detection of surface potential on the dielectric mirror side of the reading head. The first one is in a predetermined proximity to the surface of the object being detected.
and the dielectric mirror of the read head so that the electric field due to the surface potential of the object to be detected is sufficiently small and is applied to the light modulating material layer member and the dielectric mirror in the read head. The reading head and the object to be detected are connected so that the side of the object and the surface of the object whose surface potential is to be detected are sequentially and alternately changed to a predetermined second spaced apart positional relationship. and means for relatively driving displacement of the position.

A means for inputting a laser beam from the transparent electrode side of the reading head described above, a means for photoelectrically converting the laser beam emitted from the reading head, and a means for photoelectrically converting the laser beam emitted from the reading head.
Output from the photoelectric conversion means in response to the detection result of the surface potential of a specific part of the detected object when the reading head is positioned at one of the second two positions predetermined. signal storage means for storing the electric signal stored in the signal storage means; Said optical conversion corresponding to the detection result of the surface potential of the object to be detected detected by the read head while the read head is positioned at the other predetermined position of the second two positions. an electrical signal output from the means;
The present invention provides an apparatus for generating an electrical signal corresponding to a surface potential distribution, comprising means for obtaining a difference signal from the electrical signal read out from the signal storage means described above.

(Example) Hereinafter, an electric signal generating device corresponding to the surface potential distribution of the present invention will be described in detail with reference to the accompanying drawings. 1st
The figure is a block diagram of an embodiment of the electrical signal generator corresponding to the surface potential distribution of the present invention, and FIGS. 2 and 3 are time charts for explaining the operation. In the electric signal generating device corresponding to the surface potential distribution of the present invention shown in the first @, LS is a laser light source, Pdef is an optical deflector, and Lfc is an fθ lens.

Pbs is the beam splitter, Hr is the read head, Et
is a transparent electrode, PML is a light modulating material layer member, DML is a dielectric mirror, O is a detected object whose surface potential is to be detected,
wp is a wave plate, PL is a polarizer, Lfc is a condensing lens, P
D is a photodetector (photoelectric converter), SW is a changeover switch, L
M is 1 line memory.

SUB is a subtracter, DM is a drive mechanism, and laser light source L
A linearly polarized laser beam having a predetermined plane of polarization emitted from S is deflected in a predetermined manner by an optical deflector Pdef, for example, vertically and horizontally (like in a normal television scanning system).
After being deflected in both directions (horizontal and vertical), the fθ lens Lf
is input to fl.

The laser beam emitted from the fθ lens Lfθ is incident on the beam splitter Pbs. The beam splitter Pbs directs the laser beam incident thereon to the reading head Hr.
transparent electrode E in the read head Hr.
Inject from the t side.

The laser beam incident on the reading head Hr is in a state of scanning at a constant linear velocity due to the action of the fθ lens Lfθ.

For example, the reading head Hr described above may include a transparent electrode Et.
and a light modulating material layer member PML (a light modulating material layer member P that exhibits a characteristic of changing the state of light depending on an applied voltage and exhibiting a vine-like characteristic)
ML (for example, a material layer for light modulation such as a monocrystalline niobium oxide having an electro-optic effect is used)
) and a dielectric mirror DML can be used.

As described above, the reading head Hr includes the transparent electrode Et and the light modulating material layer member PMLj, which exhibits characteristics such that the state of light can be changed depending on the applied voltage.
For example, a material layer for light modulation such as a monocrystalline niobium oxide having an electro-optic effect is used)) and a dielectric mirror DML are laminated.

5. In the electric signal generation device corresponding to the surface potential distribution of the present invention, when detecting the surface potential of the object O to be detected by the reading head Hr, the dielectric mirror DM side of the reading head Hr and the surface potential The reading head Hr is assumed to be in a first positional relationship in which the surface of the object to be detected 0, which is the object of detection, is in a predetermined close state and a state in which the electric field due to the surface potential of the object to be detected 0 is sufficiently small. As given to the light modulating material layer member PML and the dielectric mirror DML in the section, the dielectric mirror DML side of the reading head Hr and the surface of the detected object 0 whose surface potential is to be detected The positions of the reading head Hr and the object to be detected 0 are relatively driven and displaced by the drive mechanism DM so that being done.

In the embodiment shown in the first diagram, when the drive signal Pd is supplied to the control signal supply terminal 1 of the drive mechanism DM, the dielectric mirror DM of the read head Hr
A predetermined first position where the L side approaches and faces the surface of the detected object 0, and a predetermined second position where the L side faces the surface of the detected object O while being separated from the surface. However, a structure is used in which the reading head Hr is driven and displaced so that it can be sequentially and alternately positioned.

In the configuration of the electric signal generating device corresponding to the surface potential distribution of the present invention, when the read head Hr detects the surface potential of the detected object 0, the detection of the surface potential on the dielectric mirror DML side of the read head Hr is performed. The first positional relationship in which the surface of the object to be detected O, which is the object of the The dielectric mirror DML side of the reading head Hr and the surface of the object to be detected O whose surface potential is to be detected are connected so as to be applied to the light modulating material layer member PML, the dielectric mirror DML, etc. The driving device is such that the positions of the reading head Hr and the detected object 0 can be relatively driven and displaced by a driving mechanism DM so that the positions of the reading head Hr and the detected object 0 are sequentially and alternately changed to a predetermined spaced second positional relationship. If so, as in the configuration example shown in FIG.
Even if it is made to be driven displaced by M.

Alternatively, contrary to the above, the detected object 0 may be driven and displaced by the drive mechanism DM,
Further, the drive mechanism may be of any type, such as electromagnetic type, electrodynamic type, electrostrictive type, etc., based on the driving principle.

The drive mechanism DM shown in FIG. 1 is configured as a so-called voice coil motor, and in the figure, 4 is a magnetic field generating part, 5 is a moving coil part, 6 is a center holding part, and 7 is the drive mechanism DM. When driving power is supplied to the terminal 1 of the drive unit DM, the movable portion including the movable coil 5 reciprocates over a predetermined distance in the direction of the arrow X in the figure. Thus, a predetermined first position where the dielectric mirror DML side of the reading head Hr approaches and faces the surface of the detected object 0.

The object of surface potential detection is set so that the electric field due to the surface potential of the detected object 0 described above is applied to parts such as the light modulating material layer member PML and the dielectric mirror DML in the reading head Hr in a sufficiently small state. Detected object○
and a predetermined second position spaced apart from each other.

Since the light modulating material layer member PML in the reading head Hr is applied with the electric field by the detected object O via the dielectric mirror DML, the reading head H
The laser beam incident on 'r passes through the light modulating material layer member PM L according to the electric field generated by the charge pattern applied to the side of the dielectric mirror DML that enters the charge image reading head Hr. The state of the light (in the case of the above example, the angle of the plane of polarization) changes.

Therefore, as described above, the laser beam incident from the transparent electrode Et side of the reading head Hr passes through the light modulating material layer member PML and is reflected by the dielectric mirror DML, and then passes through the light modulating material layer member PML again and becomes transparent. The state of the light emitted from the surface of the electrode Et (in the case of the above example, the angle of the polarization plane) is
It changes in correspondence with the potential distribution of the charge image on the object to be detected 0 described above.

As described above, the light emitted from the reading head Hr is such that the amount of rotation of the plane of polarization of the light incident on the reading head Hr changes depending on the surface potential distribution of the object to be detected. After the light emitted from the reading head Hr is reflected by the beam splitter Pbs, a wave plate WP for adjusting the amount of light, which is provided as necessary, and a wave plate WP for converting the amount of rotation of the polarization plane into a change in brightness are used. The light is incident on the condensing lens Lfc via the polarizer PL, and the condensing lens L fC
Arrange a photodetector (photoelectric converter) PD at the focal point of the
Then, from the photoelectric converter PD, an electric signal (video signal) whose amplitude changes depending on the amount of charge in each part of the charge image on the object O is obtained by scanning with the laser beam.

That is, when the laser beam incident on the reading head Hr performs two-dimensional scanning in both the vertical and horizontal directions (two-dimensional scanning similar to the horizontal scanning and vertical scanning in the television system), the The two-dimensional charge image is extracted as a time-series signal from the optical converter PD.

As described above, the video signal output from the photoelectric conversion IIPD corresponds to the charge amount distribution in a two-dimensional charge image with high definition on the object O to be detected. Therefore, if a laser beam with a diameter of 1 micron is used as the readout light, for example, 10
A video signal corresponding to a high resolution of 00 lines/1 mm can be generated.

By the way, in the electric signal generation device corresponding to the surface potential distribution of the present invention, the dielectric mirror DML of the reading head Hr
A first positional relationship in a predetermined close state in which the side faces closely the surface of the object to be detected O whose surface potential is to be detected.

The dielectric of the read head Hr is applied so that the electric field due to the surface potential of the detected object 0 described above is applied to the light modulating material layer member PML and the dielectric mirror DML in the read head Hr in a sufficiently small state. body mirror DM
The above-mentioned reading head Hr is detected so that the L side and the surface of the object 0 whose surface potential is to be detected are sequentially and alternately changed to a predetermined second spaced apart positional relationship. The position of the object 0 is driven and displaced relative to the object 0, and the reading head Hr reads the charge image of the object 0 to be detected. A predetermined first positional relationship that faces the body 0 while being close to the body 0, and a predetermined second position that faces the detected body O while being separated from the surface! ! However, when the reading head Hr and the detected object O are relatively positioned so as to have the above-mentioned second positional relationship, the reading head Hr Since the electric field due to the surface potential of the object to be detected O is applied to the light modulating material layer member PML and the dielectric mirror DML in a sufficiently small state (negligably small state), reading is difficult. In a state where the head Hr and the detected object 0 are relatively positioned in the above-described second positional relationship, the detection result of the surface potential of the detected object 0 detected by the reading head Hr is the detected object 0. It does not indicate the surface potential of body O,
This shows the state of unevenness in the thickness of the light modulating material layer member PML of the reading head Hr.

Therefore, in the electric signal generation device corresponding to the surface potential distribution of the present invention, the above-mentioned 1. A specific portion of the object to be detected 0 when the relative position of the reading head Hr and the object to be detected is determined to be one of the predetermined positional relationships of the second two positional relationships. The electrical signal output from the photoelectric converter PD corresponding to the detection result of the surface potential of is stored in a storage device, and the signal stored in the storage device is used to identify the detected object 0. The relative relationship between the reading head Hr and the object to be detected is adjusted so that the surface potential of the same part as the part is set to the other predetermined positional relationship of the first and second positional relationships described above. The photoelectric converter PD corresponds to the detection result of the surface potential of a specific part of the detected object O when the position is determined.
By obtaining a difference signal between the electrical signal outputted from the electronic signal and the IT multiplied signal read from the storage device described above, the light modulating material layer member PML of the reading head Hr is used as a detection force from the reading head Hr. This is to ensure that a state free from the influence of thickness unevenness is obtained, and in the embodiment shown in the first figure, the above-mentioned signal processing is performed by the changeover switch SW, 1, line memory LM, subtractor SUB, and This is performed by a circuit configured by a subtracter S
A detection force that is not affected by the uneven thickness of the light modulating material layer member PML of the reading head Hr is sent from U B to the output terminal 3.

In FIG. 1, the output signal from the photoelectric converter PD is supplied to the movable contact C of the changeover switch SW, and the movable contact C of the changeover switch SW is connected to the switching control signal supply terminal 2.
The fixed contact A and the fixed contact I are sequentially and alternately switched at a predetermined switching cycle by the switching side 4iI signal supplied to the terminal. A 1-line memory LM is connected to the fixed contact a of the changeover switch SW, and this 1-line memory L
The output signal from M is supplied to one input terminal of the subtracter S U B. Further, the other input of the subtracter SUB is connected to the fixed contact of the changeover switch SW described above.

In the configuration example shown in the first diagram, the reading head I-1r is set in the first positional relationship described above with respect to the same part of the charge image on the detected object O, and the surface potential of the detected object O is changed for one horizontal scanning period. In addition, the reading head Hr is set in the second positional relationship described above, and the surface potential of the detected object O is detected for one horizontal scanning period, and a difference signal between the signals of each one horizontal scanning period is obtained. Since 1 is shown in the case where 1 is obtained, the storage device is 1. Although a line memory LM is used, a field memory or frame memory is used as a storage device, and the reading head Hr is set in the first positional relationship described above for the same portion of the charge image on the detected object 0. The surface potential of the object to be detected 0 is detected for one field period or one frame period, and the surface potential of the object to be detected O is detected for one frame with the reading head Hr in the second positional relationship described above. It is configured to detect only one field period or one frame period to obtain a difference signal of one field period or ]-frame period, or to obtain a difference signal in any other period. Of course, it is possible to do so.

2 and 3, as in the case of the configuration example shown in FIG. 1,
With respect to the same portion of the charge image on the object to be detected O, the surface potential of the object to be detected O is detected for one horizontal scanning period by moving the reading head Hr into the above-described first positional relationship;
Further, the surface potential of the object to be detected 0 is detected for one horizontal scanning period by positioning the reading head Hr in the second positional relationship described above, and the difference signal between the signals for each one horizontal scanning period is obtained. Each (a) in FIGS. 2 and 3 indicates the number of one horizontal scanning period, and each (b) in FIGS. 2 and 3 indicates the number of one horizontal scanning period. ) indicates the operating mode of each 1-line memory LM, and furthermore,
Each (C) in FIGS. 2 and 3 represents the reading head Hr.
is the first. It shows which of the second positions it is located. “Near” in each (Q) in Figures 2 and 3
is a state in which the reading head Hr is located in the first position,
"Release" in each (Q) in FIGS. 2 and 3 indicates a state in which the reading head Hr is located at the second position.

(Effects of the Invention) As is clear from the detailed explanation, the electric signal generation device corresponding to the surface potential distribution of the present invention has a structure in which a transparent electrode, a light modulating material layer member, and a dielectric mirror are laminated. a first positional relationship in which the dielectric mirror side of the read head and the surface of the object whose surface potential is to be detected are in a predetermined proximity; Detection of the dielectric mirror side and surface potential of the read head so that an electric field due to the surface potential of the detected object is applied to parts such as the light modulating material layer member and the dielectric mirror in the read head in a sufficiently small state. The positions of the reading head and the object to be detected are driven relative to each other so that the surface of the object to be detected is sequentially and alternately changed to a predetermined second spaced apart positional relationship. means for displacing and the transparency 11 in the read head described above! !
means for inputting a laser beam from the pole side; means for photoelectrically converting the laser beam emitted from the reading head; Output from the photoelectric conversion means in response to the detection result of the surface potential of a specific part of the detected object when the reading head is positioned at one of the second two positions predetermined. signal storage means for storing the electric signal stored in the signal storage means; The light iq corresponds to the detection result of the surface potential of the object to be detected detected by the reading head when the reading head is located at the other predetermined position of the second two positions. Since the present invention is an apparatus for generating an electric signal corresponding to a surface potential distribution, it is comprised of means for obtaining the difference No. 43 between the electric signal output from the conversion means and the electric signal read from the signal storage means described above. A video signal that can reproduce a high-quality, high-resolution reproduced image is obtained by using an optical reading means to record a charge image in the electric signal generating device that corresponds to the surface potential distribution of the surface potential distribution. An optical member used as one of the components of a read head used to easily generate light, that is, a light modulating material layer that changes the state of light according to the intensity distribution of the applied electric field. For example, when an electro-optic effect crystal such as a lithium niobate single crystal is used as a member, an anisotropic crystal such as a lithium niobate single crystal not only produces birefringence upon application of an electric field.

Since birefringence occurs due to the anisotropy of the crystal even in the absence of an electric field, that is, in the initial state where the applied electric field is zero, the phase difference between the ordinary ray and the extraordinary ray passing through the crystal depends on the thickness of the anisotropic crystal. The unevenness of the thickness of the crystal causes the unevenness of the phase difference between the ordinary ray and the extraordinary ray in the initial state described above, and the surface potential of the detected object when there is unevenness of the thickness of the light modulating material layer in the reading head. The conventional drawback that shading corresponding to the thickness unevenness of the light modulating material layer member used in the reading head occurs in the detection result can be satisfactorily solved by a simple means.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the electric signal generator corresponding to the surface potential distribution of the present invention, and FIGS. 2 and 3 are time charts for explaining the operation.9LS...laser light source, PL ...Polarizer, Pbs...Beam splitter, WP...Wave plate, Pd5f...Optical deflector, 0...
・The object to be detected whose surface potential is to be detected, Hr...
Reading head, Et...transparent electrode, PML...light modulating material layer member, DML...dielectric mirror, Lfθ...
fθ lens, Lfc...condenser lens, PD...photodetector (photoelectric converter), SW...changeover switch, LM/
...1 line memory, SUB...subtractor, DM...
Drive mechanism, patent applicant: Victor Japan Co., Ltd.

Claims (1)

[Claims] A read head configured by laminating a transparent electrode, a light modulating material layer member, and a dielectric mirror, and a dielectric mirror side of the read head and a surface of a detected object whose surface potential is to be detected. The electric field due to the predetermined first positional relationship in close proximity and the surface potential of the object to be detected is sufficiently small to be applied to parts such as the light modulating material layer member and the dielectric mirror in the reading head. The dielectric mirror side of the reading head and the surface of the object to be detected whose surface potential is to be detected are sequentially and alternately changed to a predetermined spaced apart second positional relationship. means for relatively driving and displacing the positions of the reading head and the object to be detected; means for inputting a laser beam from the transparent electrode side of the reading head; and photoelectric conversion of the laser beam emitted from the reading head. and the means to
The above-mentioned method corresponds to the detection result of the surface potential of a specific part of the object to be detected when the reading head is located at one of the above-described first and second positions. a signal storage means for storing the electric signal outputted from the photoelectric conversion means; and a first means for storing the surface potential of the same part of the object to be detected as the specific part where the signal stored in the signal storage means was detected. , the photoelectric conversion is performed in response to the detection result of the surface potential of the object to be detected detected by the reading head while the reading head is positioned at the other predetermined position of the second two positions. An electric signal generating device corresponding to a surface potential distribution, comprising means for obtaining a difference signal between an electric signal output from the means and an electric signal read from the signal storage means.