JPS6348141B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a method of operating a scan converting storage tube;
More specifically, the present invention relates to an operating method that enables erasing in a short time to a state with less unevenness in a scan conversion type storage tube incorporating a storage target using an insulating single crystal substrate.

Prior Art A conventional scan conversion type storage tube generally includes a vacuum outer wall 1, a cathode 2, a control grid 3, an acceleration electrode 4, a collimation electrode 5, a field mesh electrode 6, and a storage target 7, as shown schematically in FIG. , a deflection coil 8, and a focusing coil 9. Then, as the storage target 7, SiO ₂ storage layers are formed in stripes or islands on a silicon substrate having a back electrode, or as shown in FIG. , a collector electrode 11 having regular rectangular or cylindrical openings is used. This type of scan-converting storage tube allows images or other information to be recorded in charge patterns and read out non-destructively. However, since information is written using the secondary electron emission of the SiO ₂ accumulation layer or the glass substrate 10, the writing speed depends on the secondary electron emission rate δ of the SiO ₂ accumulation layer or the glass substrate 10. limited to several M in terms of frequency
It is only possible to obtain a writing speed of Hz, making it impossible to write high-frequency signals with high-speed transient phenomena and few repetitions, and is mainly used in the field of image storage where writing speeds are slow. The writing speed of conventional storage tubes is also limited by electromagnetic deflection.
Even if there were no limitation due to electromagnetic deflection, the secondary electron emission rate in the storage target 7 would limit it to the above-mentioned several MHz.

Problems to be Solved by the Invention In order to solve the above-mentioned drawbacks, the present inventors proposed a storage target using an insulating single crystal substrate. However, it has been found that good erasing is not possible with this new storage target even if the erasing method used in conventional storage tubes is applied. That is, conventionally, for example, the cathode 2 is grounded, the control grid 3 is set to 0 to -75V, the acceleration electrode 4 is set to 350V, the collimation electrode 5 is set to 300V, the field mesh electrode 6 is set to 650V, and the collector electrode 11 is set to erase, write, It operates by applying the voltage required for reading. For erasing, for example, in prime mode, a voltage of 300 V, which is higher than the first cross voltage V ₁ (approximately 30 V in the case of a glass substrate), is applied to the collector electrode 11 to perform electron beam bombardment on the entire surface, and the storage surface 12 is connected to the collector electrode 11. The voltage is set to the same potential, and then, for example, 20V is applied to the collector electrode 11, and the storage surface 12 in a state where the first cross voltage V ₁ or less is bombarded with an electron beam to bring the storage surface 12 to the cathode potential. was. However, even if this method is applied to a storage tube using an insulating single-crystal substrate, it is impossible to perform erasing with little unevenness in a short time.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an operation method that enables erasing with less unevenness in a storage tube using an insulating single crystal substrate.

Means for Solving the Problems In order to achieve the above objects, the present invention provides an electrostatic focusing electrostatic deflection type electron gun having a field mesh electrode and an electron storage device having at least a collector electrode on an insulating single crystal substrate. In a scan conversion type storage tube including a target, V _K +V ₁ <V _C <V _M (where, V _K is the potential of the cathode of the electron gun, and V ₁ is the secondary electron potential of the storage surface of the storage target. The potential V _C of the collector electrode is set so as to satisfy the following conditions: a first cross voltage at which the emission rate δ is 1, V _C is the potential of the collector electrode, and V _M is the potential of the field mesh electrode. Then, the potential V _C of the collector electrode is set so that V _C <V _K and V _S <V _K +V ₁ are satisfied, and the storage target is bombarded with an electron beam. is bombarded with an electron beam, and then V _S <V _K +V ₁
A scan conversion type, characterized in that the erase potential difference is obtained by satisfying the following conditions and increasing the potential V _C of the collector electrode to a value higher than the potential V _K of the cathode while bombarding the accumulation surface with an electron beam. This relates to the method of operation of the storage tube.

Another invention of the present application is a scan conversion type storage tube including an electrostatic focusing electrostatic deflection type electron gun having a field mesh electrode and a storage target having at least a collector electrode on an insulating single crystal substrate. , V _K +V ₁ <V _C <V _M (where, V _K is the potential of the cathode of the electron gun, V ₁ is the first crossing voltage at which the secondary electron emission rate δ of the storage surface of the storage target is 1, V _C is the potential of the collector electrode, V _M is the potential of the field mesh electrode), and the potential V _C of the collector electrode is set so as to satisfy the following conditions, and the storage target is bombarded with an electron beam; Next, the potential V _C of the collector electrode is increased until the condition of V _K ≦V _C <V _K +V ₁ is satisfied.
and lowering the potential V _M of the field mesh electrode or lowering the potential of the back electrode of the storage target to capacitively reduce the potential V _S of the storage surface such that V _K ≦V _S <V The present invention relates to a method of operating a scan conversion storage tube characterized in that an erase potential difference is obtained by bombarding the storage target with an electron beam to a value that satisfies the condition of _K + V ₁ .

Operation In the first step (prime mode) of each of the above inventions, the potential V _C of the collector electrode is set lower than the potential V _M of the field mesh electrode, as in the conventional method, but the target of the present invention is Since it is made of an insulating single crystal substrate, the potential V _S of the storage surface is higher than that of the conventional one. For this reason, if
In the next step, even if the potential V _C of the collector electrode is set below the first cross voltage with respect to the cathode according to the conventional method and the storage surface is bombarded with an electron beam, the storage surface cannot be brought to the cathode potential. Have difficulty. On the other hand, in the first invention of the present application, a step is provided to lower the potential V _C of the collector electrode below the cathode potential V _K , and in the second invention, the potential of the field mesh electrode or the back electrode is lowered. Since a lowering step is provided to lower the potential of the storage surface, a predetermined erase potential difference can be obtained in a short time with little unevenness.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The electrostatic focusing electrostatic deflection scanning converting type storage tube according to the embodiment of the present invention is illustrated in FIG. 25, a vertical deflection plate 26, a horizontal deflection plate 27, a collimation electrode 28, a field mesh electrode 29, and an accumulation target 30. That is, an electrostatic focusing electron gun, an electrostatic deflection plate, and a collimation electrode 28.
, a field mesh electrode 29, and an accumulation target 30 disposed opposite to the field mesh electrode 29.

As shown in FIG. 4, the storage target 30 includes an insulating single crystal substrate 31 and a conductive collector having a plurality of regularly arranged openings 32a that are in close contact with one surface of the insulating single crystal substrate 31. It has an electrode 32. The insulating single crystal substrate 31 not only emits secondary electrons by electron beam impact, but also generates electron-hole pairs in the solid, and the electrons and holes have a relatively long lifespan. In this example, it is made of Al ₂ O ₃ single crystal (saphire) belonging to the rhombohedral crystal system with a purity of 99.9% or more and a resistance value of 10 ¹⁴ Ωcm or more at room temperature. ing. Insulator single crystal substrate 31 is Al ₂ O ₃
MgO belongs to equiaxed crystal system, not limited to single crystal
+Al ₂ O ₃ single crystal (spinel), MgO single crystal, CaF ₂
It may be formed of a single crystal or the like. In the case of Al ₂ O ₃ single crystal, it has anisotropy, but it can be carried out with any plane orientation, especially R plane (1102), A plane (1010),
C-plane (0011) etc. is desirable.

The collector electrode 32, which is in close contact with the insulating single crystal substrate 31, is coated with chromium by vapor deposition or sputtering.
It is deposited to a thickness of 1 μm or less, and striped openings 32a are regularly provided using microfabrication technology, so that the accumulation surface 33 is regularly exposed. Of course, the opening 32a of the collector electrode 32 may be hexagonal, square, rectangular,
It may be circular or the like, and the collector electrode 32 may be formed of a metal other than chromium or a semiconductor thin film that provides conductivity.

Next, the operation of the storage tube according to the first embodiment of the present invention will be described. When using this storage tube, for example, the potential V _K of the cathode 21 is set to -900V, the control grid 22 is set to 0 to -75 V with reference to the cathode potential V _K = -900V, and the acceleration electrode 23 and the asteig electrode 25 are and the collimation electrode 28 are grounded, the focusing electrode 24 is -800V, and the field mesh electrode 29 is grounded.
The potential V _M of the collector electrode 32 is set to 1400 V, and the potential V _C of the collector electrode 32 is set to a value required in each of the prime, erase, write, and read modes.

First, for convenience, the prime mode will be described with reference to FIG. 5, in which the cathode potential V _K is shown as a ground potential (reference potential). In the prime mode, the collector electrode 32 is connected to the prime power source _P by the switch S as shown in FIG. Possible voltage i.e.
The entire surface of the accumulation target 30, that is, all the accumulation, is set at a voltage of V _K +V ₁ or more and less than the potential V _M of the field mesh electrode 29 (for example, 2300 V with respect to the cathode), for example, 200 to 1000 V with respect to the cathode 21. The surface 33 is bombarded with an electron beam. More specifically, scanning equivalent to two frames of television scanning is performed with a target current of 0.1 to 0.2 .mu.A. In the case of this embodiment, the change in the secondary electron emission rate (number of secondary electrons/number of primary electrons) δ with respect to acceleration energy, that is, target (collector) voltage is as shown in FIG. 6, and the first cross voltage V ₁ is Since Al ₂ O ₃ single crystal (Saphire) with a voltage of about 15 V is used as the substrate 31, the electron beam is bombarded in the region of δ>1. During this scanning, the potential of the field mesh electrode 29 is higher than the potential of the collector electrode 32, so the secondary electrons emitted from the storage surface 33 are captured by the field mesh electrode 29, and the potential V _S of the storage surface 33 is Prime state (prime potential difference is several tens to hundreds of volts higher than the potential V _C of the collector electrode 32)
If V _P , the state becomes V _P =V _S −V _C ), and it is possible to reliably eliminate the distinction between the written portion and the non-written portion before the prime.

Next, the collector electrode 32 is connected to the erasing power supply E by the switch S, and the potential of the collector electrode 32 is
V _C is lower than the cathode potential V _K and 2 of the storage surface 33
The potential that makes the secondary electron emission rate δ smaller than 1 (V _K
The entire storage surface ₃₃ is bombarded with an electron beam at a potential of, for example, -950 to -1000 volts (-50 to -100 volts with respect to the cathode 21).
That is, beam scanning is performed by setting the collector potential V _C to V _C <V _K +V ₁ −V _P so that V _S <V _K +V ₁ . As a result, the potential V _S of the storage surface 33, which has been increased in the prime mode, becomes about the cathode potential V _K or lower.

Next, when the potential V _C of the collector electrode 32 is gradually increased while satisfying the condition of V _S <V _K +V ₁ and bombarding the storage surface 33 with an electron beam, the potential V _S of the storage surface 33 increases. is maintained at approximately the cathode potential V _K by the action of the electron beam (δ<1). Due to this action, the potential of the collector electrode 32
V _C can be made higher than the potential V _K of the cathode 21 while maintaining the potential V _S of the storage surface at approximately the cathode potential V _K . That is, by increasing the potential V _C of the collector electrode 32, the potential of the storage surface 33 also tends to rise, but the storage surface 33 is in the state of δ<1, that is, V _S <V _K +V ₁ . Since it is maintained at this state, it is returned to approximately the cathode potential V _K by electron beam bombardment. Therefore, an erase potential difference V _E =V _C -V _S (for example, 10 V) can be generated between the collector electrode 32 and the storage surface 33. This makes it possible to write.

Now the erase potential difference V _E is lower than the first crossing voltage V ₁
We have described the case where it is set to 10V, but if you want to make the erase potential difference V _E higher than the first cross voltage V ₁ , you can apply an electron beam impact to the storage surface 33 and keep it at the cathode potential. The voltage of the collector electrode 32 is set to -880V, for example, and the erase potential difference is set to 20V.

By the way, since the storage target 30 using the insulating substrate 31 has a very fast writing speed, it becomes the same as partially priming due to overwriting, etc., and the prime potential difference V _P becomes large, making it impossible to erase using the conventional method. A case has occurred where it cannot be executed.
However, according to the method of the present invention, it becomes erasable. Also, even in normal operation, afterimages may not disappear for a long time, but even in such cases, it is possible to uniformly erase them using the method of the present invention.

The reason why it is difficult to erase using the conventional method when a single crystal substrate 31 is used is that since an insulating single crystal is used as the substrate 31, the accumulation surface 3
3 has good insulation properties, and the storage surface 33 is maintained at a higher potential, thereby increasing the potential V _P after priming, and connecting the collector electrode 32 to the cathode 2 during erasing.
Even if the first cross voltage V is set to less than ₁ with respect to 1,
The potential V _S of the storage surface 33 is the potential of the collector electrode 32
This is the sum of V _C and prime potential V _P , which is the first
This seems to be because the cross voltage exceeds _V1 . In addition, in the case of the Sapphire single crystal substrate 31, the first cross voltage V ₁
is approximately 15V, which is lower than that of SiO ₂ -based substrates, which seems to have an effect.

When writing information to storage surface 33, target 30 is selectively bombarded with a modulated electron beam. At this time, switch the collector electrode 32 to S.
is connected to the write power source W, and a voltage higher than the voltage (1400 V) of the field mesh electrode 29, for example, +9.1 kV (+10 kV with respect to the cathode) is applied to the collector electrode 32. This writing changes the potential of the storage surface 33 to a first cross potential with respect to the cathode.
Since the voltage is V ₁ or more, the potential of the storage surface 33 written by the beam impact varies from 9090 V (9990 V to the cathode) to 9100 V (to the cathode), which is almost equal to the potential of the collector electrode 32, depending on the amount of electron beam impact. (10000V). Further, the potential of the storage surface 33, which is not bombarded by the electron beam, is 9090 volts (9990 V with respect to the cathode), which is the collector electrode potential V _C minus the erase potential difference V _E =10 V. As a result, a charge pattern having a potential difference of 0 to -10 V with respect to the collector electrode 32 is formed on the target surface.

If this storage tube is bombarded with a writing electron beam,
Since the storage surface 33 is formed of the insulating single crystal substrate 31, not only secondary electrons are emitted, but also secondary electrons are emitted.
Electron-hole pairs are generated within the substrate 31, that is, within the solid. The insulating single crystal substrate 31 is a sapphire with a low impurity concentration and low crystal defects, which has a long lifetime τ of electron-hole pairs and a large mobility μ, so that it can be absorbed by electron beam bombardment to a depth of about 1 μm or less from the accumulation surface. The generated electron-hole pairs are separated by an electric field as shown in the one-dimensional band diagram of FIG. 7, and the holes h neutralize the negative charges on the accumulation surface 33 and raise the surface potential. The electrons e drift and are captured by the collector electrode 32. The capture efficiency not only depends on the impurity concentration of the substrate 31 and the lifetime τ of crystal defects, that is, electrons and holes, and the mobility μ, but also depends on the shape of the collector electrode 32, the thickness of the substrate 31, the accumulation surface 33, etc. It also depends on the potential difference with the collector electrode 32 and the like.

As mentioned above, in this storage tube, writing is performed by both the secondary electron emission effect and the solid-state amplification effect due to the generation of electrons and holes in the solid. In the region where acceleration energy is large, the solid-state amplification effect occurs as shown in Figure 8. dominated by. Figure 8 shows the relationship between the acceleration energy (keV) of the electron beam and the electron impact effect (relative value), which is proportional to the writing speed, where a represents the contribution from the secondary electron emission effect and b represents the contribution within the solid. This shows the contribution from the amplification effect. As is clear from FIG. 8, the secondary electron emission effect contributes to the electron impact effect (writing speed) up to about 3 KeV, but it hardly contributes above this. On the other hand, the in-solid amplification effect increases in proportion to the acceleration energy. In addition, in the region exceeding the acceleration energy corresponding to the field mesh potential V _M (2300 V with respect to the cathode) shown by the dotted line in FIG. 8, the secondary electrons are redistributed to the storage surface 33, so that The electron emission effect deviates from the intrinsic one.
The storage target 30 according to this embodiment has an in-solid amplification effect as described above, but a conventional target with an amorphous or polycrystalline storage layer has almost no in-solid amplification effect.

When reading the charge pattern generated by writing, the collector electrode 32 is connected to the reading power supply R via the switch S, and the voltage is set to about +5V with respect to the cathode 21. A scan similar to that in a television receiver is performed to read the charge pattern. In this case, the potential of the written part is theoretically between -5V and +5V with respect to the cathode 21, but normally as much as +1V is written to the storage surface 33 in the erased state. It is possible to perform sufficient reading. Therefore, the potential of the storage surface 33 in the written state is set to about -5 to -4 V with respect to the cathode 21. In the written part, the potential of the storage surface 33 has increased, so the read beam is modulated according to the write level and flows into the collector electrode 32, but in the non-written part, the planar grid effect is large and prevents the read beam from flowing into the collector. . This makes it possible to read a charge pattern corresponding to writing. The potential of the storage surface 33 is, for example, -4V with respect to the cathode 21 in the written part, and -4V with respect to the cathode 21 in the unwritten part, for example.
The reading beam does not reach the storage surface 33 because it is 5V and has a more negative potential than the cathode. Therefore, even when reading is performed, the charge pattern on the storage surface 33 is not destroyed. This type of reading method is called non-destructive reading, and this storage tube makes it possible.

Next, an operating method according to the second embodiment will be described. The prime mode in this second embodiment is the same as the prime mode in the first embodiment. That is, the potential V _C of the collector electrode 32 is set to a voltage (V _K +V ₁
The storage surface 33 is bombarded with an electron beam by setting the voltage above (for example, -900+15=-885V) and below the potential V _M of the field mesh electrode 29, for example, 200 to 1000V to the cathode 21. This results in
The same prime state as in Example 1 is obtained. next
Collector potential until V _K ≦V _C <V _K +V ₁ is satisfied.
V _C is lowered, and then the potential V M of the field mesh electrode 29 connected to the power source _M is lowered by several hundred volts or more (for example, 1000 V), and the potential V _S of the storage surface 33 is lowered.
is capacitively reduced, and the potential V _S of the storage surface 33
is set to a state of V _K ≦V _S <V _K +V ₁ and the storage surface 33 is bombarded with an electron beam. As a result, the potential V _S of the storage surface 33 becomes approximately the cathode potential V _K . And δ<1
While maintaining the electron beam impact in the state shown in FIG. Also, during the electron beam impact in this state of δ<1, the field mesh electrode 2
Return the potential of 9. Note that the potential is capacitively coupled
If V _K <V _C is set when V _S is lowered, when V _S = V _K due to electron beam impact, an erase potential difference of V _C − V _K is obtained, which simplifies the operation.

In this embodiment, it is possible to obtain a predetermined erase potential difference V _E without providing a back electrode on the target 30, but for convenience of explanation, it is assumed that a back electrode 34 is provided as shown in FIG. , accumulation surface 33
and collector electrode 32, field mesh electrode 2
9 and the back electrode 34, and when the field mesh electrode _potential V _M is lowered _{, the potential V S of} the storage surface 33 is also lowered in a capacitive manner. It becomes possible to satisfy V _K ≦V _S ≦V _K +V ₁ .

Next, a third embodiment of the present invention will be described. This embodiment is a modification of the second embodiment, in which a back electrode 34 is provided as shown in FIGS. This relates to a method of lowering the potential V _S of the storage surface 33 by lowering the potential of the back electrode 34 instead of lowering the potential of the storage surface 33 in a capacitive coupling manner. Therefore,
A power source B for the back electrode is connected to the back electrode 34 as shown in FIG. In this embodiment, for example, the back electrode 34 is set to the same potential as the collector electrode 32, and a prime operation similar to that of the first and second embodiments is performed to obtain a prime state. After that, the potential V _C of the collector electrode 32 is lowered so that V _K ≦V _C ≦V _K +V ₁
satisfy. After that, the potential of the back electrode 34
V _B is lowered, for example, by about 100 V, and the potential V _S of the storage surface 33 is made lower than V _K + V ₁ using the coupling by the capacitor C _B , creating a state of V _K ≦V _S < V _K + V ₁ , and the electron beam impact to do. Then, while maintaining the potential V _S of the storage surface 33 at approximately the cathode potential V _K , the potential of the collector electrode 32 is increased to obtain a predetermined erase potential difference _VE . In addition,
In order to obtain an erase potential difference higher than the first cross voltage, the method explained in the first embodiment is adopted, or the electron beam is applied with a voltage higher than the voltage of the collector electrode 32 applied to the back electrode 34. A shock is generated, and then the voltage of the back electrode 34 is lowered to lower the potential of the storage surface 33, thereby creating a potential difference greater than or equal to the first cross voltage between the storage surface 33 and the collector electrode 32.

The capacitive coupling of the target 30a shown in FIG. 10 will be explained in more detail. It is assumed that the collector electrode 32 is formed in a stripe shape and extends perpendicularly to the plane of the paper, and this direction is defined as the Y axis. The width of the collector electrode 32 is 2L, and the pitch is 2L. Also, the thickness is
Although it is approximately 0.1 μm, it will be ignored here. The direction of the storage surface 33 perpendicular to the collector electrode 32 is selected as the X axis, and the direction perpendicular to the storage surface 33 is selected as the Z axis. It is assumed that the field mesh electrode 29 is Z _D from the storage surface 33 , the thickness of the substrate 31 is Z ₁ , and the back electrode 34 is located at that position. When the geometrical system is determined in this way, the capacitance distribution C _(X) in the X direction of the storage surface 33 is given by the following equation.

C _(X) = -1/2L (1 + ε _S ) ε ₀ {tanπ/2 [1-1/
L(x+l)]-tanπ/2 [1-1/L(x-l)]}+ε ₀ (1-l/L)ε _S
/Z ₁ +ε ₀ (1-l/L) 1/Z _D (1) Here, ε ₀ is the dielectric constant of vacuum, and ε _S is the effective dielectric constant of the substrate 31. The first term in equation (1) indicates the relationship between the capacitive coupling between the storage surface 33 and the collector electrode 32, and the second term
The term indicates the relationship between the coupling C _B with the back electrode 34, and the third term indicates the coupling C _M with the field mesh electrode 29.
This is a term that shows the relationship between The important thing is the accumulation aspect 33
The difference is that the magnitude of capacitive coupling depends on X. Therefore, when the unit of each electrode is changed, the potential V _S of the storage surface 33 becomes a function of X depending on the strength of capacitive coupling. Therefore, in the present invention, the accumulation surface 33
Although the potential is treated as if it were constant, it should be interpreted as the effective average potential. Of course, even when the collector electrode 32 has a different shape, the potential V _S of the storage surface 33 becomes a function of the shape. Therefore, the potential V _S of the storage surface 33 is interpreted as an effective average potential. Equation (1) is derived from the example shown in FIG. 10, but the magnitude of capacitive coupling has a very large dependence on geometric shape. Therefore, in the present invention, an appropriate operating potential must be set in accordance with these.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto and can be further modified. For example, erasing in a target having a back electrode 34 can be performed in the same manner as in the first and second embodiments.

Effects of the Invention As is clear from the above, according to the present invention, even if the target uses an insulating single crystal substrate,
It is possible to erase evenly.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of a conventional storage tube, FIG. 2 is a partially enlarged sectional view showing the target of the storage tube of FIG. 1, and FIG. 4 is a partially enlarged sectional view showing the target of the storage tube of FIG. 3; and FIG. 5 is a diagram illustrating the operation of the storage tube of FIG. 3. 6 is a graph showing the relationship between the acceleration energy of the single crystal substrate and the secondary electron emission rate in the storage tube of FIG. 3, and FIG. 7 is an explanatory circuit diagram of the target in the storage tube of FIG. 3. An explanatory one-dimensional band diagram, FIG. 8 is a graph showing the target secondary electron emission effect and solid-state amplification effect in the storage tube of FIG. 3, and FIG. 9 is a graph related to the second embodiment of the present invention. A circuit diagram illustrating a target portion of an electrostatic focusing electrostatic deflection scan conversion type storage tube,
FIG. 10 is an enlarged cross-sectional view of the target of FIG. 9. In the symbols used in the drawings, 29 is a field mesh electrode, 30 is a target, and 3 is a field mesh electrode.
1 is an insulating single crystal substrate, 32 is a collector electrode, 3
3 is the accumulation side.

Claims (1)

[Scope of Claims] 1. A scan conversion type storage tube including an electrostatic focusing electrostatic deflection type electron gun having a field mesh electrode and a storage target having at least a collector electrode on an insulating single crystal substrate. , V _K +V ₁ <V _C <V _M (where, V _K is the potential of the cathode of the electron gun, V ₁ is the first crossing voltage at which the secondary electron emission rate δ of the storage surface of the storage target is 1, V _C is the potential of the collector electrode, V _M is the potential of the field mesh electrode), and the potential V _C of the collector electrode is set so as to satisfy the following conditions, and the storage target is bombarded with an electron beam; Next, the potential V _C of the collector electrode is set so that V _C <V _K and V _S <V _K +V ₁ are satisfied, and the storage target is bombarded with an electron beam _. ＜V _K +V ₁
A scan conversion type, characterized in that the erase potential difference is obtained by satisfying the following conditions and increasing the potential V _C of the collector electrode to a value higher than the potential V _K of the cathode while bombarding the accumulation surface with an electron beam. How storage tubes work. 2. In a scan conversion type storage tube including an electrostatic focusing electrostatic deflection type electron gun having a field mesh electrode and a storage target having at least a collector electrode on an insulating single crystal substrate, V _K +V ₁ < V _C <V _M (where, V _K is the potential of the cathode of the electron gun, V ₁ is the first cross voltage at which the secondary electron emission rate δ of the storage surface of the storage target is 1, and V _C is the voltage of the collector electrode The storage target is bombarded with an electron beam by setting the potential V _C of the collector electrode so as to satisfy the following conditions: V _K is the potential of the field mesh electrode, and V M is the potential of the field mesh electrode, and then V _K ≦ The potential of the collector electrode V _C until the condition of V _C <V _K +V ₁ is satisfied.
and lowering the potential V _M of the field mesh electrode or lowering the potential of the back electrode of the storage target to capacitively reduce the potential V _S of the storage surface such that V _K ≦V _S <V A method for operating a scan conversion type storage tube, characterized in that the erase potential difference is obtained by bombarding the storage target with an electron beam to a value that satisfies the condition of _K + V ₁ .