JP2010212087A - Imaging element, and radiation resistant camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging element having radiation resistance equivalent to that of an imaging tube, and to provide a radiation resistant camera. <P>SOLUTION: An imaging element 20 includes: a vacuum container VC having a translucent window 10; a plurality of stripe-shaped transparent anodes 9 running in a first direction in the vacuum container; a photoelectric conversion film 8 converting light received through the window to holes; a plurality of stripe-shaped field emission cold cathodes 7 emitting electrons for reading the holes and running in a second direction crossing the first direction; and a voltage switching arrangement 4A identifying a position of an image signal by applying a voltage between one of the transparent anodes and one of the cold cathodes and sequentially changing the combination of them. By using the imaging element, a radiation resistant camera is constituted such that signals in both cases when radiation is shielded and not shielded can be obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging device and a radiation-resistant camera that are suitable for use in a so-called high radiation environment such as a nuclear facility and outer space, and have high radiation resistance.

Conventionally, in a high radiation environment (> 10 ³ Gy) by various electromagnetic waves and particle beams such as nuclear facilities and outer space, radiation resistant cameras mainly using an imaging tube have been used.

Further, in a low radiation environment (<10 ³ Gy), a radiation resistant camera using a solid-state imaging device such as a CCD or a CID has been used.

  Further, the conventional field emission type cold cathode imaging device is configured as a tripolar structure, that is, as a tripolar structure in which a gate electrode is arranged between a transparent electrode anode and a cold cathode cathode. The emission of electrons from the cold cathode cathode was controlled by controlling the potential (see Patent Document 1, etc.).

JP-A-6-176704

  The production of the imaging tube is currently being reduced worldwide, and a new type of radiation-resistant imaging device is demanded instead.

  Similarly, in the solid-state imaging device, due to physical properties as a semiconductor, ionization noise is generated inside the device due to radiation, the crystal structure is easily broken, and actually has radiation resistance equivalent to that of the imaging tube. Not in.

  The present invention has been made in view of such a point, and an object thereof is to provide an imaging element and a radiation-resistant camera having radiation resistance equivalent to that of an imaging tube.

The image sensor of the present invention is
A vacuum vessel having a translucent window;
In the vacuum vessel, a plurality of transparent electrode anodes in the form of stripes provided inside the translucent window and running in a first direction;
In the vacuum vessel, provided inside the transparent electrode anode, and converts the light received through the window into holes, a photoelectric conversion film,
In the container, a plurality of stripe-shaped, which are provided at a predetermined distance from the photoelectric conversion film, emit electrons for reading the holes, and run in a second direction intersecting the first direction. A plurality of field emission type cold cathode cathodes, each cold cathode cathode having a plurality of cone-shaped emitters arranged in the longitudinal direction;
A voltage switching device that specifies a position of a video signal by applying a voltage between the transparent electrode anode and the cold cathode cathode, and sequentially changing a combination thereof;
It is comprised as provided with.

The image sensor of the present invention is
A vacuum vessel having a translucent window;
In the vacuum vessel, a plurality of transparent electrode anodes in the form of stripes provided inside the translucent window and running in a first direction;
A plurality of stripe-shaped driver electrodes provided in the vacuum vessel and running in a second direction intersecting the first direction;
A photoelectric conversion film that is sandwiched between the transparent electrode anode and the driver electrode and converts received light into holes,
A plurality of stripe-shaped field emission cold cathodes that run in the first direction and that emit electrons to read holes, are provided at a predetermined distance from the photoelectric conversion film in the container. A cathode,
The transparent electrode anode for applying a voltage between the one driver electrode in a state where a voltage is applied between the field emission type cold cathode cathode and the one driver electrode is sequentially selected. A voltage switching device that identifies the video signal position,
It is comprised as provided with.

The radiation-resistant camera of the present invention is
An imaging device according to any of the above,
A shielding plate that is provided in front of the translucent window in the imaging device and performs an opening / closing operation for switching between shielding and non-shielding of radiation;
A control circuit for causing the shielding plate to perform the opening / closing operation in synchronization with a synchronization signal;
A circuit that obtains a signal with reduced image noise due to radiation by taking the difference between the image signal of the image sensor at the closing operation of the shielding plate from the image signal of the image sensor at the opening operation of the shielding plate;
It is comprised as having.

The radiation-resistant camera of the present invention is
An imaging device according to any of the above,
A rotatable filter body disposed in front of the translucent window in the image sensor, the translucent filter for allowing light to reach the image sensor by rotation, and radiation reaching the image sensor A filter body that operates to alternately position a shielding plate that shields the front surface of the imaging element;
Control that operates so as to obtain, from the image sensor, a video signal based on light transmitted through the translucent filter and a video signal during a shielding operation by the shielding plate based on a rotation synchronization signal of the filter body. Circuit,
It is comprised as provided with.

The radiation-resistant camera of the present invention is
An imaging device according to any of the above,
A rotatable filter body disposed in front of the translucent window of the image sensor, and having a sensitivity to radiation, and a translucent filter that allows light to reach the image sensor by rotation. A filter body that operates to alternately position the phosphor portion having the phosphor on the front surface of the imaging device; and
A control circuit that operates to obtain an image signal based on the light transmitted through the translucent filter and an image signal from the phosphor from the image sensor based on the rotation synchronization signal of the filter body;
It is comprised as provided with.

The radiation-resistant camera of the present invention is
An imaging device according to any of the above,
A rotatable filter body disposed in front of the translucent window of the image sensor, and having a sensitivity to radiation, and a translucent filter that allows light to reach the image sensor by rotation. A filter body that operates so that a phosphor part having a phosphor and a shielding plate that shields radiation from reaching the image sensor are alternately positioned on the front surface of the image sensor;
Based on the rotation synchronization signal of the filter body, an image signal based on the light transmitted through the translucent filter, an image signal by the phosphor, and an image signal at the time of shielding by the shielding plate are obtained from the imaging device. A control circuit that operates as
It is comprised as provided with.

  According to the present invention, it is possible to provide an imaging device and a radiation resistant camera having radiation resistance equivalent to that of the imaging tube.

(A) to (c) is a perspective explanatory view, a longitudinal explanatory view, and a plan explanatory view of an image sensor according to an embodiment of the present invention. FIG. 3 is an explanatory perspective view of an example of a cathode tip (emitter) shown in FIG. 1. (A) to (c) is a perspective explanatory view and a longitudinal explanatory view showing a part of the image sensor shown in FIG. (A) And (b) is a perspective explanatory view and a longitudinal section explanatory view in the state where a part of the radiation-resistant camera according to the embodiment of the present invention is omitted and the other part is seen through. A video signal processing circuit for radiation-resistant cameras. (A) to (c) are front explanatory views showing different examples of the rotary filter shown in FIG. Schematic which shows the use condition of a radiation-proof camera. FIGS. 3A to 3C are a perspective explanatory view, a longitudinal explanatory view, and a plan explanatory view of an image pickup device according to an embodiment different from FIG. 1. (A) And (b) is longitudinal explanatory drawing which shows the example from which a cold cathode cathode (emitter) differs, respectively. (A) And (b) is a principle explanatory drawing of the image sensor which this inventor knows, and the image sensor of the present invention.

  The embodiment of the present invention will be briefly described along with the background to the achievement of the embodiment, and then the embodiment of the present invention will be described in more detail.

  As can be seen from the above description, the solid-state imaging device has the following drawbacks.

  That is, the solid-state imaging device uses, as a principle, electronic excitation between band gaps due to light energy in a semiconductor. For this reason, electronic excitation is performed not only by light energy but also by radiation, and radiation noise is generated. As a result, the obtained image signal is remarkably deteriorated, and the element itself is deteriorated due to the destruction of the crystal structure due to radiation. In practice, long-term use is difficult.

  As described above, the present invention has been made in view of such points, and the solid-state imaging device as an embodiment thereof is hardly damaged by radiation, and is composed of metal and amorphous (glass, ceramic). Is done. In other words, the operation principle of the field emission type cold cathode solid-state imaging device as the embodiment of the present invention configured as described above is compared with FIG. This will be described with reference to an example.

  FIG. 10A shows a field emission type cold cathode solid-state imaging device (triode imaging device) shown as a comparative example. This element is an image pickup element using a field emission type cold cathode cathode, and basically has a three-pole configuration including an anode, a gate, and a cathode (103, 106, 102, 108). That is, first, in FIG. 10A, the anode is the photoelectric conversion film 103, the gate is the gate electrode 106, and the cathode is the base 108 and the emitter (cathode chip) 102 thereon. As can be seen from FIG. 10A, in this image sensor 20, a high electric field is applied to the tip of the emitter (cathode chip) 102 on the substrate 108 by the power source 101, and the electron 107 is extracted by the tunnel effect. An electron gun 100 as a cathode and a photoelectric conversion film 103 facing each other across the vacuum environment VE are provided. The gate electrode 106 is a gate electrode made of a fine metal mesh. Further, in FIG. 10A, reference numeral 109 denotes an insulating layer.

  In such an image sensor 20, when light 104 hits the photoelectric conversion film 103, holes 105 are formed in the photoelectric conversion film 103 by the energy of the light 104. The holes 105 are neutralized by electrons from the electron gun 100, and a video signal is finally obtained from the image sensor 20.

  As described above, in the field emission type cold cathode imaging device (triode imaging device) of the comparative example shown in FIG. 10A, a uniform strong electric field is generated around the cold cathode (emitter 102). A gate electrode 106 made of mesh was installed to form a three-pole structure. In other words, the reason why the tripolar structure is used in this way is that the field emission type cold cathode cathode (emitter 102) of the comparative example has a sharp tip and varies in the direction in which the tip faces. That is, the reason why the tripolar structure is used is that in the comparative example as described above, the electric field at the tip of the cathode (emitter 102) is simply a two-polar configuration of the anode (photoelectric conversion film 103) and the cathode (emitter 102). Since the intensity is lower than the electron emission potential energy (work function) from the cathode (emitter 102), the electron field emission phenomenon is unlikely to occur, and the field emission electrons obtained also have a large variation in intensity distribution. It is.

  For this reason, in the imaging device 20 of the comparative example of FIG. 10A, in order to solve such a point, the gate electrode 106 is disposed near the tip of the cold cathode cathode (emitter 102), and the cathode ( Even when the tip shape of the emitter 102) is not sharp and the direction in which the tip is directed varies, a uniform high electric field strength is obtained.

  Thus, the image pickup device 20 of the embodiment of the present invention shown in FIG. 10B and the image pickup device 20 of the comparative example of FIG. 10A are stored in the photoelectric conversion film 103 as the anode side. The principle is that the image signal is read out by holes and electrons emitted from the cathode (emitter 102) by the field emission phenomenon.

  As described briefly above, the imaging device 20 of the embodiment of the present invention shown in FIG. 10B is made using a metal or amorphous material having a strong resistance to radiation as a main material. Therefore, it has the same radiation resistance as an imaging tube that does not use semiconductors.

  Furthermore, as can be seen from FIG. 10B, the tip of the emitter 102 is made sharper and the gate electrode is not used. That is, in the embodiment of the present invention, the gate electrode is unnecessary, and control is performed only by the potential of the anode (photoelectric conversion film 103) that is a transparent electrode.

  The other configuration of FIG. 10B is substantially the same as that of FIG. 10A, and the same reference numerals are given to the same parts, and detailed description thereof is omitted.

  Further, the phenomenon utilized in the image sensor shown in FIGS. 10A and 10B will be described as a field electron emission phenomenon. In simple terms, this phenomenon is that when a large electric field strength is applied to the tip of the cold cathode and the potential potential exceeds the work function of the electrode material, electrons are emitted into the vacuum due to the tunnel effect. is there.

  Therefore, in order to efficiently perform this field electron emission phenomenon, for example, in the imaging device of the comparative example of FIG. 10A, the gate electrode 106 is provided closer to the cold cathode (emitter 102). The field emission from the cathode (emitter 102) is turned on and off by 106.

  In the apparatus of FIG. 10A, since the gate electrode 106 is provided in this way, it is inevitable that a portion that is shadowed by the gate electrode 106 is inevitably generated, and the element structure itself becomes complicated. There was a problem.

  On the other hand, in the embodiment of the present invention shown in FIG. 10B, the gate electrode is unnecessary, and control is performed only by the potential on the anode (photoelectric conversion film 103) side as a transparent electrode.

  As described above, in the imaging device according to the embodiment of the present invention, since the gate electrode is not used, naturally, a portion that is shaded by the gate electrode does not occur, and the expected photoelectric conversion film 103 of the anode as a transparent electrode is formed. Electrons can accurately reach the portion, and the image resolution can be improved.

  Hereinafter, the above-described embodiment of the present invention will be described in more detail with reference to FIGS. 1 (a), (b), and (c).

  As described above, the imaging device (bipolar imaging device) 20 of the embodiment of the present invention shown in FIGS. 1A, 1B, and 1C is made of a metal and an amorphous material so as not to be easily damaged by radiation. (Glass, ceramic, etc.).

  FIG. 1A is a perspective view of an image sensor 20 according to an embodiment of the present invention, FIG. 1B is an explanatory view of a vertical section, and FIG. In particular, in FIG.1 (c), the translucent window (glass) 10 is abbreviate | omitted. In these drawings, for example, in FIG. 1B, the upper side is a so-called anode side, and the lower side is a so-called cathode side.

  As can be seen from FIG. 1A in particular, the image pickup device 20 includes a vacuum container VC. The bottom plate of the vacuum vessel VC is, for example, an insulating so-called substrate 1. As shown in FIG. 1C in particular, a plurality of stripe-shaped field emission cathodes 7, 7,... Running in the horizontal direction in the figure are parallel to each other on the inner surface of the substrate 1. Is provided. Each of the cold cathode cathodes 7 is configured to have a plurality of cone-shaped cathode tips (emitters) 7B, 7B,... On a striped substrate 7A. An enlarged view of the cathode tip 7B is shown in FIG. As can be seen from FIG. 2, the cathode tip 7B is made of Ni in a cone shape, and has an emitter width of 1.6 μm and a tip curvature of 2.5-5.0 nm, for example. Each cold cathode cathode 7 is insulatively held in a state where both end portions are lifted by the insulating material 2 as can be seen from FIG. An external power source (not shown) is connected to each cold cathode cathode 7 via a voltage switching device 4B and wiring 3, as can be seen from FIG. Thereby, the voltage of an external power supply can be applied to each cold cathode cathode 7 as an operation voltage suitable for operation via the voltage switching device 4B.

  As can be seen from FIG. 1 (a) in particular, above the cold cathode cathodes 7, 7,..., The photoelectric conversion film 8, the transparent electrode anodes 9, 9,. A light window 10 is provided in an opposing state. More details are as follows. That is, the uppermost portion is a light-transmitting window 10. Inside the window 10, a plurality of striped transparent electrode anodes 9, 9,... Are provided. The planar shape of the striped transparent electrode anodes 9, 9,... Is particularly shown in FIG. As can be seen from FIG. 1A, a photoelectric conversion film 8 is formed further inside the plurality of striped transparent electrode anodes 9, 9,. The voltage switching device 4A is electrically connected to the plurality of striped transparent electrode anodes 9, 9,... From an external power source (not shown) through the wiring 3.

  It will be as follows if it sees about the material of each above-mentioned structural member. As described above, a plurality of striped transparent electrode anodes 9, 9,... Are attached to the inside of the light-transmitting window 10 for incident light. -Oxide of tin) film can be used. The photoelectric conversion film 8 can be made of amorphous material, the field emission type cold cathode cathode 7 can be made of metal, and the insulating material 2 and the vacuum vessel VC can be made of ceramic or glass. These materials are all materials having no crystal structure, and the radiation damage is slight. The damage is considered to be negligible in practice.

  Further, as the cold cathode 7, one of the inventors of the present invention previously invented alone or jointly, the so-called mold transfer mold method (Template method) (field emission cold cathode device and its manufacturing method, A cold cathode cathode (hereinafter referred to as a vacuum nanodevice) manufactured using a field electron emission cold cathode manufacturing method called Kaihei 10-92301 and JP-A-2000-285798 can be used. According to the mold transfer molding method, as described above, the tip tip curvature is 2.5-5.0 nm and the width of one nanoemitter is 1.6 μm. ) Can be obtained. Thereby, a sharpness of 1/10 to 1/100 of the tip curvature of the conventional cold cathode cathode can be realized. In addition, according to the mold transfer molding method, it is possible to obtain an extremely uniform tip and height.

  In order to confirm the effect of the embodiment of the present invention, the present inventor actually used several kinds of vacuum nanoemitters and actually produced several types of cold cathode imaging devices having a diode that is not a conventional triode structure. did. That is, first, an image sensor without an insulating material 2 (see FIG. 1B) was made as a prototype. In this imaging device, the discharge phenomenon from the outer peripheral edge of the vacuum nanoemitter (cold cathode cathode 7) frequently occurs and exceeds the emission current from the tip of the vacuum nanoemitter, and good imaging device characteristics are obtained. I couldn't.

  Based on this result, the present inventor coated the outer peripheral edge of the vacuum nanoemitter (cold cathode cathode 7) with an electrical insulating material such as ceramic or mica in order to solve this problem. As a result, the discharge phenomenon from the edge could be avoided, and good imaging characteristics could be confirmed. That is, it has been found that according to the imaging device 20 of the embodiment of the present invention shown in FIGS. 1A, 1B, and 1C, the operational effects peculiar to the present invention can be obtained.

  When the operational effects of the embodiment of the present invention are viewed from a driving method as an element, in a conventional planar matrix type imaging element (for example, Japanese Patent Laid-Open No. 6-176704, an imaging apparatus and its operation method), a gate and a cathode The video signal position is specified by applying a voltage between them and sequentially switching the voltage. However, the embodiment of the present invention does not require a gate, and therefore, the position of the video signal can be specified by applying a voltage between the anode and the cathode and sequentially switching the voltage.

  More specifically, the translucent window (glass) 10, the transparent electrode anodes 9, 9,..., And the photoelectric conversion film 8 shown in FIGS. 1 (a), (b), and (c) are more specifically described. 3 (a) and 3 (b) can also be configured.

  In the example of FIGS. 3 (a) and 3 (b), as can be seen from FIG. 3 (b) which is a cross-sectional view taken along line AA of FIG. 3, light shielding is performed between the transparent electrode anodes 9, 9,. Plates 21, 21,... Are provided. In other words, in this embodiment, a thin film photoelectric conversion film 8 is placed on a plurality of linear (striped) transparent electrode anodes 9, 9,. For this reason, if there is no said light-shielding plate 21, 21, ..., as shown to Fig.3 (a), the light which injected between the transparent electrode anode 9 and the adjacent transparent electrode anode 9 will be shown. Then, it enters the portion of the photoelectric conversion film 8 at a position where the electrode 9 is not present, and generates holes therein. Since there is no anode electrode 9 in the hole generating portion, electrons from the cold cathode cathode 7 do not reach and cannot be read, but the photoelectric conversion film 8 is positively abnormally charged, and the electric field inside the device is reduced. This may cause distortion and may cause the image sensor to not function normally. For this reason, in the embodiment of the present invention, the light-shielding plate 21 is disposed between the linear transparent electrode anodes 9 so as to prevent light from entering this portion.

  FIG. 3C shows a modification of FIG. The difference between the example of FIG. 3C and the example of FIG. 3B is that the light shielding plates 21, 21,... Are provided on the lower side of the translucent window (glass) 10 in the figure. is there. The other points are the same.

In the embodiment of the present invention, an amorphous material is used as the photoelectric conversion film 8. This amorphous material is essentially less susceptible to noise from radiation. However, light and radiation are the same electromagnetic wave, and although the probability is low, incident radiation may generate holes in the photoelectric conversion film. Since these holes are regarded as video signals in the same manner as holes generated by light, it is required to separate them. For this reason, as an embodiment of the present invention, a shield plate that shields radiation can be provided on the front surface of the image sensor, and a mechanism for opening and closing the shield plate by a synchronization signal from the control circuit can be installed. By taking the difference between the image signal for opening the shielding plate and the image signal for closing the shielding plate, the image noise due to radiation can be eliminated.

  FIGS. 4A and 4B show examples of embodiments in which the above-described shielding plate is provided.

  That is, this embodiment is a technique known by the present inventors, that is, a color image signal is generated by a three-primary color light-transmitting filter installed on the front surface of the image sensor and rotated to synchronize with the control signal. This is an application of technology for obtaining

  This embodiment of the present invention is represented as a camera 200 shown in FIGS. 4 (a) and 4 (b). The signal processing in the camera 200 is performed by, for example, a circuit shown in FIG.

  That is, as can be seen from FIGS. 4A and 4B, the image sensor 20 is provided in the first housing 100. A lens system 51, a diaphragm 52, an aperture, and a lens system 53 are formed on the front surface of the image sensor 20. A rotation filter (filter body) 56 is provided in a second casing 101 attached to the front of the first casing 100 and having a translucent front surface so as to be rotationally driven by a motor 55. Further, a connector 61 and a radiation resistant cable 62 that transmit a signal from the image sensor 20 to the outside are attached to the opposite side of the first casing 100.

  As the rotary filter (filter body) 56, various types as shown in FIGS. 6A, 6B, and 6C are used. Among them, the example of FIG. 6A shows a filter 56 in which a shielding plate 56a and an RGB (or single color) transmissive filter 56b are combined. In this way, the three primary color filters (or single color filters) 56b and the shielding plate 56a for shielding the radiation described above are arranged on the same plane, and rotated to obtain a signal. With the rotation, the shielding plate 56a takes an open operation state that shields radiation and a closing operation that does not shield radiation.

  That is, as can be seen from FIG. 5 in particular, the rotation state of the rotary filter 56 is input to the control circuit 224 via the encoder 223. The synchronization signal from the control circuit 224 is input to the data transfer circuit 221. In the data transfer circuit 221, an image signal (radiation video signal), a translucent filter image signal, and a shielding plate image signal of the plate coated with the phosphor are respectively acquired from the image pickup signal from the image pickup device 20 of the camera 200 and corresponding. Accumulate in circuits 226, 227, 228. A radiation image signal is obtained from the circuit 226, and an optical image signal with reduced image noise due to radiation is obtained by adding the signals from the circuits 227 and 228 to the differential signal processing circuit 230. These signals are applied to the video circuit 232.

  FIG. 6B shows a combination of a transmissive filter 56b and a phosphor 56c sensitive to radiation. In this way, a plate coated with a phosphor 56c sensitive to radiation is arranged in the same plane as the filter 56b and rotated, and color (or single color) is generated by a synchronization signal from the control circuit 224. In addition to acquiring the optical image signal, the emission of the phosphor can be simultaneously acquired as a radiation image.

  FIG. 6C shows an example of a combination of the shielding plate 56a, the transmissive filter 56b, and the phosphor 56c. In this way, the three primary color filters (or single color filters), the plate coated with the phosphor 56c sensitive to radiation, and the shielding plate 56a for shielding radiation are arranged in the same plane and rotated. In addition, an optical image and a radiation image in which image noise due to radiation is reduced can be simultaneously acquired by a synchronization signal from the control circuit 224.

  FIG. 7 shows a connection example of such a camera 200. That is, a signal from the camera 200 is transmitted to the camera control unit 201, the personal computer 202, the TV monitor 203, and the recording video device 204.

FIGS. 8A, 8B, and 8C show an image sensor 30 according to another embodiment of the present invention. The positions of video signals are linear electrodes (transparent electrode anode 9 and driver electrode) orthogonal to each other. DE) makes detection possible. In FIG. 8C, the illustration of the insulating material 2 is omitted in order to facilitate understanding of the configuration of the transparent electrode anode 9 and the driver electrode DE, ie, FIGS. 8A and 8B. , (C), electrons e are emitted from the tip of the cathode tip 7B by the voltage applied between the designated one driver electrode DE and the cold cathode cathode 7. This cathode-emitter field electron emission region occurs over the entire region corresponding to one driver electrode DE. At this time, when a voltage exceeding the load voltage of the driver electrode DE is applied to one of the linear transparent electrode anodes 9, the photoelectric conversion film 8 at the intersection between the driver electrode DE and the transparent electrode anode 9 is applied. A strong electric field is formed inside. Under this electric field, the amount of holes determined by the amount of light incident on the photoelectric conversion film 8 and the electric field is generated at the intersection. The field emission electrons incident on the driver electrode DE are combined with the holes and a current flows.

  Accordingly, the position of the video signal can be specified by applying a voltage between one transparent electrode anode 9 and one driver electrode DE and sequentially switching the combination.

  The advantage of the embodiment of FIG. 8 of the present invention is that the area of electrons e emitted from the emitter E is limited to the cathode-emitter region at the intersection of one anode 9 and one cathode 7. is there.

  In the embodiment of FIG. 8 of the present invention, field emission electrons are obtained from a wide cathode / emitter region corresponding to one driver electrode DE, so that the signal current amount can be further increased compared to the embodiment of FIG. In addition, due to the effect of widening the emitter region that emits electric field, it has a feature that works well for alleviating variations in the light-signal current characteristics per pixel due to variations in emitters.

  Also in the embodiment of FIG. 8, the edge of the outer periphery of the emitter is covered with the electrical insulating material 2 such as ceramic or mica for the same reason as in the embodiment of FIG.

  As a material for a metal field emission cold cathode used in an imaging device, a pure metal such as nickel or molybdenum or an alloy thereof is used.

  In general, on a clean metal surface, a nano-order oxide film by oxygen in the atmosphere covers the metal surface, and this film serves as a barrier against the field electron emission phenomenon, and the field electron emission phenomenon cannot be obtained.

  For this measure, the metal or metal oxide is generally reduced in a high-temperature reducing gas atmosphere so that the metal surface is exposed as much as possible.

  However, it is known that even if the reduction treatment is performed, a thin oxide film is instantaneously formed on the metal surface even in the air or in a low vacuum.

  As a countermeasure, it takes a long time to repeatedly apply a high voltage to the reduced cathode material in a high vacuum to remove the thin oxide film. This is the manufacturing of devices using cold cathodes including image sensors. This is a major cause of the cost increase.

  Further, according to the analysis of the present inventor, it has been found that the emission of electrons from the emitter is performed not only from the sharpest part of the tip part but also from the bottom part.

  Focusing on these points, in the embodiment of the present invention, as shown in FIGS. 9A and 9B, a metal film MF made of gold, which does not form an oxide film on the surface even in the atmosphere, is formed on the field emission cold cathode cathode 7. The surface of the tip portion of the emitter E is used. That is, in FIG. 9A, the metal film MF is coated on the entire surface of the emitter E, and in FIG. 9B, the metal film MF is coated on the tip of the emitter E. As a result, electrons can be emitted from the tip as much as possible.

  The gold thin film MF can be coated on the surface of the emitter E by a plating method or a chemical vapor deposition film growth method. Since the surface of the emitter E that emits field electrons is covered with the gold thin film MF, an oxide film is not formed. Therefore, the reduction treatment is unnecessary, and the electric field is obtained only by a simple surface treatment such as chemical cleaning with acetone or pure water. The electron emission phenomenon can be obtained, and the manufacturing process can be greatly shortened.

  The various embodiments and modifications described above can be applied to both the embodiment shown in FIG. 1 and the embodiment shown in FIG.

  As described above, according to the embodiment of the present invention, it is possible to provide an imaging device having radiation resistance comparable to that of an imaging tube not using a semiconductor.

  In addition, since this imaging device does not include a gate electrode, the conversion efficiency of the optical-electrical signal is high, the structure is simple, and the manufacturing yield can be improved.

  Further, since electrons are emitted from the cold cathode emitter, these electrons do not flow into the gate electrode but almost all reach the photoelectric conversion film. For this reason, it has become possible to read the video signal in the shaded area of the gate electrode that has not been seen so far.

DESCRIPTION OF SYMBOLS 1 Substrate 2 Insulating material 3 Wiring 4A Voltage switching device 4B Voltage switching device 7 Cold cathode cathode 7A Base body 7B Cathode chip 8 Photoelectric conversion film 9 Anode 10 Translucent window 20 Image sensor 21 Light shielding plate 30 Image sensor 56 Rotation filter 56a Shielding Plate 56b Transmission filter 56c Phosphor 200 Radiation resistant camera DE Driver electrode MF Metal film

Claims (9)

A vacuum vessel having a translucent window;
In the vacuum vessel, a plurality of transparent electrode anodes in the form of stripes provided inside the translucent window and running in a first direction;
In the vacuum vessel, provided inside the transparent electrode anode, and converts the light received through the window into holes, a photoelectric conversion film,
In the container, a plurality of stripe-shaped, which are provided at a predetermined distance from the photoelectric conversion film, emit electrons for reading the holes, and run in a second direction intersecting the first direction. A plurality of field emission type cold cathode cathodes, each cold cathode cathode having a plurality of cone-shaped emitters arranged in the longitudinal direction;
A voltage switching device that specifies a position of a video signal by applying a voltage between the transparent electrode anode and the cold cathode cathode, and sequentially changing a combination thereof;
An image pickup device comprising: A vacuum vessel having a translucent window;
In the vacuum vessel, a plurality of transparent electrode anodes in the form of stripes provided inside the translucent window and running in a first direction;
A plurality of stripe-shaped driver electrodes provided in the vacuum vessel and running in a second direction intersecting the first direction;
A photoelectric conversion film that is sandwiched between the transparent electrode anode and the driver electrode and converts received light into holes,
A plurality of stripe-shaped field emission cold cathodes that run in the first direction and that emit electrons to read holes, are provided at a predetermined distance from the photoelectric conversion film in the container. A cathode,
The transparent electrode anode for applying a voltage between the one driver electrode in a state where a voltage is applied between the field emission type cold cathode cathode and the one driver electrode is sequentially selected. A voltage switching device that identifies the video signal position,
An image pickup device comprising:   The imaging device according to claim 1, wherein the photoelectric conversion film is made of an amorphous material, and the cold cathode cathode is made of a metal material.   The image sensor according to claim 1, wherein a light shielding material is disposed between a pair of adjacent transparent electrode anodes.   5. The image pickup device according to claim 1, wherein the cold cathode cathode is one in which a surface of a tip portion of each of a plurality of cone-shaped emitters is coated with a gold thin film. . An imaging device according to any one of claims 1 to 5,
A shielding plate that is provided in front of the translucent window in the imaging device and performs an opening / closing operation for switching between shielding and non-shielding of radiation;
A control circuit for causing the shielding plate to perform the opening / closing operation in synchronization with a synchronization signal;
A circuit for obtaining a signal with reduced image noise due to radiation by taking a difference between the image signal of the image sensor at the closing operation of the shielding plate from the image signal of the image sensor at the opening operation of the shielding plate;
A radiation-resistant camera comprising: An imaging device according to any one of claims 1 to 5,
A rotatable filter body disposed in front of the translucent window in the image sensor, the translucent filter for allowing light to reach the image sensor by rotation, and radiation reaching the image sensor A filter body that operates to alternately position a shielding plate that shields the front surface of the imaging element;
Control that operates so as to obtain, from the image sensor, a video signal based on light transmitted through the translucent filter and a video signal during a shielding operation by the shielding plate based on a rotation synchronization signal of the filter body. Circuit,
A radiation-resistant camera comprising: An imaging device according to any one of claims 1 to 5,
A rotatable filter body disposed in front of the translucent window of the image sensor, and having a sensitivity to radiation, and a translucent filter that allows light to reach the image sensor by rotation. A filter body that operates to alternately position the phosphor portion having the phosphor on the front surface of the imaging device; and
A control circuit that operates to obtain an image signal based on the light transmitted through the translucent filter and an image signal from the phosphor from the image sensor based on the rotation synchronization signal of the filter body;
A radiation-resistant camera comprising: An imaging device according to any one of claims 1 to 5,
A rotatable filter body disposed in front of the translucent window of the image sensor, and having a sensitivity to radiation, and a translucent filter that allows light to reach the image sensor by rotation. A filter body that operates so that a phosphor part having a phosphor and a shielding plate that shields radiation from reaching the image sensor are alternately positioned on the front surface of the image sensor;
Based on the rotation synchronization signal of the filter body, an image signal based on the light transmitted through the translucent filter, an image signal by the phosphor, and an image signal at the time of shielding by the shielding plate are obtained from the imaging device. A control circuit that operates as
A radiation-resistant camera comprising:

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