JP2007040935A - Electromagnetic wave sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic wave sensor capable of detecting independently an electromagnetic wave and a visible ray respectively at the same time, and capable of analyzing accurately and quickly respective signals therein. <P>SOLUTION: This sensor includes a transparent base body 2, a visible ray sensor part 3 and a radiation sensor part 4 layered in order on the transparent base body 2, and a bias electrode 5 formed between the visible ray sensor part 3 and the radiation sensor part 4, detects the visible ray incident from a transparent base body 2 side, between the bias electrode 5 and a visible ray reading electrode 3a provided in the visible ray sensor part 3, and detects a radiation incident from the transparent base body 2 side, between the bias electrode 5 and a radiation reading electrode 4a provided in the radiation sensor part 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electromagnetic wave sensor having both visible light and radiation sensor functions.

  Radiation monitoring equipment is installed as a means for constantly monitoring the radiation environment in places such as nuclear power plants and medical radiation imaging devices. This radiation monitoring facility includes a radiation detector that monitors radiation leakage and the like, and constantly monitors radiation information obtained from an image sensor of the radiation detector. Further, a visible light sensor device is installed as means for detecting the presence or absence of a human body or the like in a radiation environment. This visible light sensor device uses a sensor element using CCD (Charge Coupled Device), CMOS (Complementary Metal-Oxide-Semiconductor), or the like that detects visible light and outputs an image signal. Monitoring is performed with a camera or digital camera. Conventional. These radiation detectors and visible hole sensor devices have been installed as independent devices, but recently, a method has been proposed in which signals from both devices are detected by a single device and extracted as pixel signals. (See Patent Document 1).

However, as described above, a device having both radiation and visible light sensor functions can detect each signal and extract it as a pixel signal, but it is difficult to distinguish and extract signals from both simultaneously. It is. This is because there is only one light receiving part having a sensor function and only one signal extracting part. When two types of light are received at a time, the output signal is extracted as a mixed signal. This is because it seems difficult to discriminate. Therefore, at present, each sensor device has to be installed separately, and it is necessary to secure the respective installation locations, and there is a problem that it is expensive in terms of cost.
JP 2000-244824 A

  Therefore, an object of the present invention is to provide an electromagnetic wave sensor that can detect electromagnetic waves and visible light independently and simultaneously, and can accurately and quickly process analysis of each signal. Another object of the electromagnetic wave sensor of the present invention is to consolidate the radiation detector and the visible hole sensor device, which have been separately installed conventionally, into one, and can be installed at a low cost without taking up an installation place.

  In order to solve the above-described problems, an electromagnetic wave sensor according to the present invention includes a transparent substrate, a visible light sensor unit and a radiation sensor unit that are sequentially stacked on the transparent substrate, and visible light incident from the transparent substrate side. Is detected by the visible light sensor unit, while radiation incident from the transparent substrate side is detected by the radiation sensor unit.

  In one example of the present invention, a bias electrode is formed between the visible light sensor unit and the radiation sensor unit, and visible light is transmitted between the bias electrode and a visible light reading electrode provided in the visible light sensor unit. And detecting radiation between the bias electrode and a radiation reading electrode provided in the radiation sensor unit.

  According to the present invention, since the function of detecting electromagnetic waves such as radiation and the function of detecting light such as visible light are provided independently in one sensor, electromagnetic waves and visible light can be detected simultaneously. In addition, each detected signal can be analyzed independently without being confused. In addition, since two types of sensor devices that have conventionally been installed independently can be integrated into one, only one installation location is required, and the cost required for equipment can be reduced.

Hereinafter, preferred embodiments of the electromagnetic wave sensor according to the present invention will be described in detail. In addition, although embodiment of this invention is shown with a figure, this invention is not limited to this.
The configuration of the electromagnetic wave sensor according to the present invention is such that a photoconductor layer is placed above and below a bias electrode in order to simultaneously achieve a function of detecting electromagnetic waves such as radiation and a function of detecting light such as visible light at the same time. And an electrode for taking out both lights as an electrical signal.

  FIG. 1 is a diagram schematically showing a configuration example of an electromagnetic wave sensor according to the present invention. In this figure, an electromagnetic wave sensor 1 according to the present invention includes an insulating transparent substrate 2 that transmits visible light, such as glass and transparent resin, a visible light sensor unit 3 formed in a layer on the transparent substrate 2, and radiation. A sensor unit 4 and a bias electrode 5 formed between the sensor units 3 and 4 are provided.

  The transparent substrate 2 can be constituted by a flexible resin sheet in addition to the glass described above. For example, a polymer film can be used as the sheet. Examples of the polymer film include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), polyetherimide, polyetheretherketone, polyphenylene sulfide, polyarylate, polyimide, and polycarbonate (PC). The film which becomes is mentioned. By using such a plastic film, the weight can be reduced as compared with the case where a glass substrate is used, portability can be improved, and resistance to impact is improved.

  The visible light sensor unit 3 has a function for monitoring the movement of a person or an object, converts it into an electric signal corresponding to the intensity of the visible light (darkness difference), and takes it out as an electric charge and a current amount. The visible light reading electrode 3a and the visible light conductor 3b are formed in layers. The visible light reading electrode 3a has an electrode structure capable of image recognition like a two-dimensional matrix using a thin film transistor. The applied material is not particularly limited as long as it is a conductive material that transmits visible light. Platinum, gold, silver, nickel, chromium, copper, iron, tin, antimony lead, tantalum, indium, palladium, tellurium, Rhenium, iridium, aluminum, ruthenium, germanium, molybdenum, tungsten, tin oxide / antimony, indium tin oxide (ITO), etc. can be used, among which platinum, gold, silver, copper, aluminum, indium, ITO And carbon are preferred.

  As a method for forming the visible light reading electrode 3a, for example, a conductive thin film is formed by vapor deposition, sputtering, or the like using the above-mentioned material, and this conductive thin film is formed using a known photolithographic method or lift-off method. Or a method of thermally transferring the conductive thin film onto a metal foil such as aluminum or copper, or a method of etching using a resist such as inkjet.

  On the other hand, the visible light conductor 3b reflects the photocharge (carrier) generated therein as a current value flowing between the visible light reading electrode 3a and a radiation reading electrode 4a of the radiation sensor unit 4 described later. is there. As the material of the visible light conductor 3b, an organic photoconductive material that does not show a change in electric resistance against electromagnetic waves is preferable, while its electric resistance decreases when irradiated with visible light.

  The organic photoconductive material is selected from a substance having a charge generation function and a substance having a charge transport function. The visible light conductor 3b is formed as a two-layer structure in which the substance having a charge generation function and a substance having a charge transport function are laminated, or a single-layer structure in which the two kinds of substances are mixed.

  Examples of charge generation materials having a charge generation function include azo pigments such as Sudan Red or Diane Blue, quinone pigments such as pyrenequinone and anthanthrone, indigo pigments such as indigo and thioindigo, azurenium salt pigments, copper phthalocyanine, metal-free phthalocyanine, Selected from phthalocyanine pigments such as titanyl phthalocyanine.

  On the other hand, as a charge transport material having a charge transport function, for example, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, styryl compounds, hydrazone compounds, pyrazoline derivatives, oxazolone derivatives, benzothiazole derivatives, Benzofuran derivative, acridine derivative, phenazine derivative, aminostilbene derivative, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, styryl compound, amine derivative, distyryl compound (above p-type), benzoquinone Compound, anthraquinone compound, naphthoquinone compound, naphthalene diimide compound, fluorenone compound, thiopyran compound, indane compound, indanji Emissions-based compounds, cyclopentadiene-based compounds and their nitro derivatives, cyano derivatives, dicyano-methylene derivative, malonic acid ester derivative is selected from among such Fueniruimino derivatives (or n-type).

  The visible light conductor 3b is obtained by dispersing an appropriate amount of the organic photoconductive material in a binder resin such as polyester, polycarbonate, polystyrene, polyvinyl butyral, polyvinyl acetate, acrylic resin, polyvinyl pyrrolidone, ethyl cellulose, and cellulose acetate butyrate. Formed. The formed visible light conductor 3b has a thickness of about 0.01 to 10 μm, preferably 0.1 to 5 μm.

  On the other hand, the radiation sensor unit 4 converts the intensity of the radiation into an electrical signal and extracts it as electric charge and current amount, and has a radiation reading electrode 4a and a radiation conductor 4b. Specifically, radiation incident from the transparent substrate 2 is received by the radiation conductor 4b to generate an electron pair, and this can be used as a radiation input signal to detect, for example, radiation leakage.

  The radiation reading electrode 4a of the radiation sensor unit 4 is not particularly limited as long as the bias electrode 5 is a conductor having a small resistance value, but a material such as gold or aluminum that is easy to form a film is preferable. . One of the radiation conductors 4b is preferably a photoconductive material having high absorbability with respect to high-energy electromagnetic waves. For example, a cadmium compound such as CdTe or CdS, a selenium compound such as Se, SeTe, or SeAs, ZnS, or ZnSe. Such heavy elements as zinc compounds and the like, and compounds thereof can be applied. More preferably, a photoconductive material containing one or more heavy elements having an atomic number of 30 or more is preferable. Of these, selenium, arsenic, tellurium and the like having a high X-ray absorption rate are particularly preferable.

  The bias electrode 5 of the present invention is provided so as to be sandwiched between the visible light conductor 3b and the radiation conductor 4b, and can uniformly bias the upper and lower conductors 3b and 4b. Examples of the material used for the bias electrode 5 include metals such as Au, Pt, Ni, and In, and thick amorphous semiconductor films. As another method, a carbon tape may be attached to the visible light conductor 3b and the radiation conductor 4b on the side in contact with the bias electrode 5 to form the bias electrode 5, or conductive fine particles such as carbon black and nickel fine particles may be used. A dispersed film-like or paste-like electrical connection material may be used.

  As shown in FIG. 1, the electromagnetic wave sensor 1 having the above configuration includes a visible light sensor unit 3 and a radiation sensor unit 4 arranged above and below a bias electrode 5, and a transparent substrate above the visible light sensor unit 3. It consists of a layered structure in which 2 is arranged. In addition, the visible light sensor unit 3 has a layer shape with the visible light reading electrode 3a and the visible light conductor 3b, and the radiation sensor unit 4 has a layer shape with the radiation reading electrode 4a and the radiation conductor 4b. The electromagnetic wave sensor 1 of the present invention is, for example, between the visible light reading electrode 3a and the visible light conductor 3b and between the visible light conductor 3b and the bias electrode 5 within the above basic configuration. An intermediate layer is provided between the bias electrode 5 and the radiation conductor 4b and between the radiation conductor 4b and the radiation reading electrode 4a, so that the SN ratio of the sensor can be increased and each sensor function can be improved. .

  Next, the detection operation of the electromagnetic wave sensor 1 having the above configuration will be described. In FIG. 2, the bias polarity applied to the bias electrode 5 may be either positive or negative. When the bias polarity is negative, when visible light A is incident from the transparent substrate 2 side of the electromagnetic wave sensor 1, the visible light near the visible light reading electrode 3a is visible. Visible light is absorbed by the photoconductor 3b, electron-hole pairs are formed, and holes move to the side of the bias electrode 5 that is the counter electrode. As a result, the charge density of the visible light conductor 3b is increased and the resistance value is significantly reduced. The bias voltage applied to the bias electrode 5 is reflected in the current value flowing between the upper and lower electrodes, and the current value is detected. Therefore, it can be used as a visible light sensor. The bias voltage applied to the bias electrode 5 is preferably about 0 to 50V.

  FIG. 3 shows the operation when acting as a radiation sensor. When the radiation B is incident from the transparent substrate 2 side, a pair of electron holes is formed by the radiation conductor 4b, and each moves to a counter electrode of opposite polarity. As a result, the charge density of the radiation conductor 4b is increased and the resistance value is greatly reduced, and the current value flowing between the upper and lower electrodes is reflected by the bias voltage applied to the bias electrode 5, and the current value is detected. Therefore, it can be used as a radiation sensor. The electromagnetic wave sensor 1 of the present invention is effective for detecting ultraviolet rays, gamma rays, electron beams and the like having energy higher than ultraviolet energy.

  EXAMPLES Examples relating to the present invention will be described below, but the present invention is not limited thereto and can be applied.

<Example 1>
A visible light reading electrode 3a made of ITO is formed on a transparent glass substrate, and a charge generation layer made of an azo pigment and polyvinyl butyral resin as a visible light conductor 3b on the visible light reading electrode 3a, a butadiene compound as a charge transport material, and A polycarbonate resin was formed thereon by coating. Next, gold is vacuum-deposited to form a bias electrode 5, a high voltage cable is connected to one end thereof, and a silicon resin is applied to the connection portion to form a visible light reading electrode 3 a and a radiation reading electrode 4 a formed on the upper layer. The insulation relationship was secured. Further, selenium was vacuum-deposited to form a 200 μm selenium layer as the radiation conductor 4b. Finally, the electromagnetic wave sensor 1 was completed by vacuum-depositing gold to form the radiation reading electrode 4a.

<Example 2>
It was prepared in the same manner as in Example 1 except that the visible photoconductor 3b was formed of a hydrazone compound.

<Example 3>
It was prepared by the same method as in Example 1 except that the radiation conductor 4b was formed of selenium arsenide.

<Example 4>
The bias electrode 5 and the radiation reading electrode 4a were formed by the same method as in Example 1 except that the bias electrode 5 and the radiation reading electrode 4a were formed of aluminum.

<Example 5>
It was created by the same method as in Example 1 except that the visible light reading electrode 3a was made of gold.

<Example 6>
It was created by the same method as in Example 1 except that the visible light reading electrode 3a was made of aluminum.

<Example 7>
It was produced by the same method as in Example 1 except that cadmium sulfide was provided as an intermediate layer between the visible light reading electrode 3a and the visible light conductor 3b.

<Example 8>
It was prepared in the same manner as in Example 1 except that cerium oxide was provided as an intermediate layer between the radiation reading electrode 4a and the radiation conductor 4b.

  The electrical characteristics (dark current and signal current) of Examples 1 to 8 were examined. The dark current and the signal current were evaluated as follows. The evaluation results are shown in Table 1.

  Evaluation of dark current: The bias polarity to the bias electrode 5 was negative, and a value of 3 minutes was recorded in a dark place with a voltage of 1 Kv being applied. The noise component flowing in the visible light conductor 3b and the radiation conductor 4b only by bias application was evaluated based on the result of quantification. The dark current at the visible light reading electrode 3a is D11, and the dark current at the radiation reading electrode 4a is D16.

  Signal current: after the dark current measurement, uniform visible light and radiation are irradiated, and a current value flowing through the visible light conductor 3b and the radiation conductor 4b after 1 minute of irradiation is recorded. The signal components that flowed with each light were quantified. The signal current at the visible light reading electrode 3a is L12, and the signal current at the radiation reading electrode 4a is L16. At this time, the visible light was 10 Lux, the X-ray irradiation conditions were an X-ray tube voltage of 80 Kv and a dose of 1R.

  As can be seen from the above table results, the signal / noise ratio, which is a sensor function, is usable at both configurations for visible light and radiation.

  The electromagnetic wave sensor of the present invention is effectively used as a low-cost sensor means without taking up space in a place where a nuclear power plant or a medical radiation imaging apparatus is installed.

It is a conceptual diagram which shows the structure of the electromagnetic wave sensor which concerns on this invention. It is operation | movement explanatory drawing of a visible light sensor part. It is operation | movement explanatory drawing of a radiation sensor part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electromagnetic wave sensor 2 Transparent base | substrate 3 Visible light sensor part 3a Visible light reading electrode 3b Visible light conductor 4 Radiation sensor part 4a Radiation reading electrode 4b Radiation conductor 5 Bias electrode

Claims (3)

A transparent substrate;
The visible light sensor unit and the radiation sensor unit are sequentially laminated on the transparent substrate,
An electromagnetic wave sensor, wherein visible light incident from the transparent substrate side is detected by a visible light sensor unit, and radiation incident from the transparent substrate side is detected by a radiation sensor unit. A bias electrode is formed between the visible light sensor unit and the radiation sensor unit, visible light is detected between the bias electrode and a visible light reading electrode provided in the visible light sensor unit, and the bias electrode and the radiation are detected. The electromagnetic wave sensor of Claim 1 which detects a radiation between the radiation reading electrodes provided in the sensor part.   The electromagnetic wave sensor according to claim 1, wherein the visible light sensor unit includes a visible light conductor, and the visible light conductor is made of an organic photoconductive material.

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