JPS5950980B2 - X-ray sensitive photoconductive material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to materials sensitive to electromagnetic radiation, particularly to X-rays.

Furthermore, it relates to applications to X-ray recording or X-ray information processing. Conventionally, various methods have been known for recording and displaying using X-rays.

For example, silver halide photosensitive materials, coated layers of fluorescent pigments, electrophotographic photosensitive materials such as selenium, cadmium sulfide, and zinc oxide, and recently, ionography that utilizes the ionization phenomenon of gases, or electroluminescent materials and the above-mentioned Display boards and the like that combine electrophotographic photosensitive materials have been developed for medical and industrial purposes. On the other hand, these X-ray information processing materials and methods also include the following problems.
That is, silver halide photosensitive materials and ionographies, which have relatively high sensitivity, require complicated processing steps. Furthermore, electrophotographic photosensitive layers and fluorescent light emitting layers, which allow images to be obtained through simple steps, have low sensitivity, which poses a problem in terms of user safety. The main object of the present invention is therefore to provide a highly sensitive material that exhibits significant electrical conductivity to X-ray exposure.

Another object of the present invention is to provide a material that can very easily detect X-rays. The present invention is an X-ray sensitive photoelectric material characterized by having a compound represented by the following general formula (hereinafter simply referred to as a compound).

MIkXπm (where M is Mo, W, Mn, Ni, Co, Rh, Ir
, a transition metal element selected from Cu and Ag, x is V
lb group element, l, m and n are positive integers, k
There is a relationship of l■mn.

) The compound used in the present invention has high X-ray sensitivity, and the intended purpose of the present invention is achieved by this high sensitivity, and it is widely used in technical fields related to X-rays. be.

The compound according to the present invention is a compound of transition metals, and transition metals M include molybdenum, tungsten, manganese,
Suitable examples include the transition metals nickel, cobalt, rhodium, iridium, copper and silver. Suitable examples of the other element x forming the compound include Group Vlb elements such as oxygen, sulfur, selenium, and tellurium.
Some representative examples of compounds include MON2, MO
O3, MOS2, MOs3, wO2, wO3, ws2,
ws3, MnO, MnS, NiO, NiS, RhO, R
h2O3, RhS, Rh2S3, c00, c0203,
c0s, c02s3, Ir203, Ir02, Ir2s
3, Irs2, cu20, cu0, cu2s, cus,
Examples include Ag20, Ag2S, Ag2Se and Ag2Te. Although the compounds according to the present invention generally have relatively high electrical resistance, there is no need for the present invention to add a small amount of other impurity elements or to perform heat treatment for the purpose of modifying the electrical properties depending on the application. Needless to say, there is no problem.

Examples of additive elements include lanthanum rare earth elements, actinide rare earth elements, other transition metal elements, terium, copper,
Examples include silver, cadmium, lead, sodium, potassium, calcium, and strontium bismuth. Note that the heat treatment is performed in air, oxygen, nitrogen, inert gas, etc., and the electrical properties can be modified by changing the stoichiometric ratio. Application of the compounds usually occurs in two forms.

One is a relatively non-transparent layer made by dispersing fine powder of a compound in a binder, and the other is a relatively transparent thin film manufactured by vapor deposition, sputtering, etc. be. The binding material is usually a material with higher electrical insulation than a compound. Generally, organic binders include resins that have high electrical insulation and excellent mechanical properties. for example,
Preferred binders include polystyrene, polymethyl methacrylate, poly-9-vininolecanolebazole, polyethylene terephthalate, ethyl cellulose, nitrocellulose, polyvinyl chloride, and various latexes. Such a binder has an electrical resistance of 10 8 Ω·Cm or more, and is particularly appropriate when using a binder. The most common method for manufacturing a layer containing a compound is to add fine powder of the compound to a binder solution and disperse it by means such as ball milling or ultrasonic stirring, or to melt the binder. A fine powder of the compound is kneaded into the material by means such as a roll mill, and then applied onto a desired substrate to form a layer.

Similar to organic binders, it is also effective to use inorganic binders that have excellent electrical insulation properties. Some typical examples of such inorganic binders are SiO2, Al2O3, B2O3,
Glass-forming oxides such as P2O5 and mixtures thereof. A suitable amount of a compound can be added to this glass-forming oxide and formed into a layer by, for example, melting or sintering to a desired size. Depending on the properties of the binder, the amount of compound particles added can be divided into two areas.

In other words, in layers where charge carriers (electrons or holes) generated by X-ray absorption cannot be transported through the binder in compound particles, it is desirable that adjacent compound particles come into contact with each other. 10 to 500 parts by volume of compound particles are required for 100 parts by volume of the binder, and film properties,
In consideration of sensitivity and the like, 100 to 300 parts by volume is particularly appropriate. On the other hand, poly-9-vininolecarbazole, halogenated poly-9-vininolecarbazole,
Photoconductive binders such as polycenyl anthracene, polyacenaphthylene, polyvinyl acridine, and α-alkyl acrylic acid amide polymers have the property of transporting charge carriers, and in such systems, the amount of the compound is It can be reduced. For example, even if the amount of compound particles is 10 to 100 parts by volume relative to 100 parts by volume of the binder, a layer having appropriate sensitivity can be obtained. The layer containing the compound usually has a thickness of 0.1 to 5
Set to 0μ. It is also possible to use the compound itself as a thin film. To produce thin films, methods such as vapor deposition are used on well-cleaned substrates. Vapor deposition is performed by a commonly known method. Alternatively, sputtering or CVD (chemical paper deposition) may be used. A photoreceptor equipped with a layer containing a compound thus formed is
It is used as a line detector, non-contact switch, indicator, image forming device, etc.

Needless to say, these uses include
It is based on changes in electrical properties due to the wire, such as changes in resistance. For example, it is used as a detector by detecting a change in resistance (increase in current) due to X-rays in a layer containing a compound.
It is used as a non-contact switch by changing the resistance from 0N to 0FF due to the change in resistance due to X-rays, and converts the change in resistance due to X-rays into changes in optical properties (absorption rate, reflectance, refractive index, coloring, light emission, etc.). It is used as an indicator by It is also used as an electrophotographic photoreceptor in electrophotographic techniques. One of the most effective uses of the compounds is for recording or displaying X-ray projection patterns. For example, when the surface of a layer containing a compound is uniformly charged by corona discharge or the like and then exposed to X-rays that have passed through the object, a charge pattern is generated on the layer surface depending on the amount of X-rays.

This is developed with electrostatic powder toner, transferred to a desired transfer member such as a sheet film, and then fixed to obtain a permanent image. It can be used in so-called electrophotography. Also,
One example of another effective use of the present invention is a laminate of a layer containing a compound and a layer of electrically or optically variable light transmittance material. A variable light transmittance material is a material whose light transmittance changes depending on a current voltage or an electric field. For example, a material that changes depending on an electric current includes:
Examples include dynamic scattering mode liquid crystal, electrochromic titanium oxide, molybdenum oxide, niobium oxide, tungsten oxide, and viologen solution. In addition, examples of substances whose light transmittance changes depending on voltage include lithium niobate, phosphorus-added lithium zirconate titanate, and other materials. Examples include microscopic substances and electroluminescent phosphorus compounds. It goes without saying that such a substance whose optical properties change electrically may be used as a laminate with a layer containing a compound, or may be included in a layer containing a compound. Mona. stomach. In this case, as will be explained in the drawings below, it is not necessary to have a laminated structure of a layer containing a compound and a layer whose optical properties change electrically, and only one layer is sufficient. FIG. 1 shows an example of an X-ray display panel made of a layer containing a compound and a substance whose optical properties change electrically.

Reference numeral 10 indicates a display panel, and its structure is so-called Nesa glass, in which a transparent electrode 12 made of tin oxide, indium oxide, etc. is provided on a transparent substrate 11 made of glass, etc. A layer of material 13 having a varying value is laminated.

A layer 14 with a compound is then provided. A thin layer electrode 15 made of aluminum, beryllium, or the like that is highly transparent to X-rays is attached to the X-ray irradiation surface side. When an electric field is applied between the electrodes 12 and 15 using a power source 16 in this display panel, and X-rays 17 are irradiated from the electrode surface 15 side, a change in optical characteristics occurs in the layer 13, and the X-ray pattern is followed. The visible image can be observed from the substrate side. Further, when the concentration of the layer 14 is high, a white reflective layer can be inserted between the layers 13 and 14 to improve the appearance. In addition, in the case of electrophotographic recording and X-ray display, a photoconductor may be added to or laminated on the layer containing the compound for the purpose of improving sensitivity efficiency, and a photoconductor may be added or laminated to the layer containing the compound, or it may be combined with a fluorescent intensifying screen. , may be recorded and displayed. The present invention will be explained below with reference to Examples.

In addition, the unit of quantity in the examples indicates a weight ratio unless otherwise specified. Example 1 Poly-9-vinylcarbazole (BASF Dusei product name:
To 100 parts of a 6% chlorobene solution of Rubican M-170) were added 5 parts each of the 18 types of compounds shown in the following table.
Ball mill dispersion was performed for 24 hours to prepare a number of dispersions depending on the number of types of compounds.

Next, each of these dispersions was cast onto an aluminum substrate to a dry film thickness of 10 μm to form a film containing each compound. The sensitivity of these coatings was determined by electrophotographic methods.

In the measurement, first, the surface of the coating was charged with a corona charging device with an applied voltage of -6 KV, and then the attenuation characteristics of the surface potential were investigated using a device capable of intermittently performing X-ray exposure and surface potential measurement. The X-ray source has a tube voltage of 50 KV and a tube current of 4 mA.
Exposure was performed from a distance of 0 cm.

The following table shows the sensitivity of each compound in terms of the exposure dose required to half attenuate the surface potential.

The unit of exposure amount is the product of tube current and exposure time MA-Sec
It was displayed in Example 2 Among the coatings prepared in Example 1, black. 1-MOO3, ▲2-MOS3, 應3-WS3,
51 MnS, 6-NlO, black 9-COO, 11-
After charging 8 types of COS and 17-CUS in the same manner as in Example 1, X-rays were applied at 60 mA-Sec through a lead pattern.
After exposure, magnetic brush development was performed using electrostatic powder toner, and this was transferred to white paper to obtain a developed image.

All images obtained were clear. Example
3 In order to sensitize the film used in Example 2, a photoconductive layer was laminated on the film.

The photoconductive layer consists of 5 parts of photoconductor bismuth iodide and poly-9-
The layer was 5 microns thick and consisted of 5 parts of vinyl carbazole, and in order to further improve the surface properties, a 2 micron thick layer of poly-9-vinylcarbazole alone was applied to the top layer. The photoreceptor thus formed was charged in a dark room in the same manner as in Example 2, then a fluorescent intensifying screen was placed in close contact with the photoreceptor, and an X-ray projection pattern was printed in accordance with the method of Example 2.

Next, toner development was performed, and a clear image without fogging was obtained.

The X-ray exposure amount at this time was 16 mA-Sec. Further, as a control example, a photosensitive layer consisting only of bismuth iodide/poly-9-vinylcarbazole showed slight fogging even at an exposure dose of 32 mA-Sec.

Example 4 MOS3, MOO3, MnS, Ag2Se, Ag2 were added as compounds to 100 parts of an 8% toluene solution of polystyrene.
20 each of 8 types of Te, COO, COS and NiO
The above eight types of dispersion solutions were prepared by performing ball mill dispersion for 24 hours.

Each of these dispersions was used as a layer containing the compound of a display panel having the structure shown in FIG. An electromic layer 13 was provided on a 10 cm x 10 cm Nesa glass consisting of 11 and 12 shown in FIG.

This electrochromic layer consists of two layers: first, zirconium oxide is deposited on Nesa glass to a thickness of 0.3μ, and then tungsten oxide, which is an electrically colored substance, is deposited to a thickness of 0.6μ. and layered. Moreover, the first
Although not shown in the figure, a solution of titanium oxide dispersed in polystyrene was used as a reflective layer between layers 13 and 14 to form a reflective layer of 1 μm.
It was applied to a film thickness of . Next, each of the above-mentioned dispersions was applied to a thickness of 4 μm as a layer 14 having a compound, and finally, aluminum was vapor-deposited to a thickness of 1 μm as an exposure side electrode 5 to prepare a display panel. A voltage of 5 V was applied to this panel between the negative Nesa glass side and the irradiation side electrode. The current value at this time was 1 μA or less. Then, the tube current was 4 mA (7
) When exposed to X-rays, a blue X-ray projection pattern was obtained in about 15 seconds. This pattern persisted until a reverse electric field was applied. Further, the current flowing through the display panel during X-ray irradiation was 6 mA. Example 5 In place of the layer containing the compound used in Example 4, a layer containing the following compound and having a thickness of 1 .mu.m was formed by vapor deposition.

The compounds used were MOO3, NiO, Ag2O, COO
and CuS.

This display panel displayed a persistent blue image as in Example 4. Example 6 A layer containing a compound was created using B2O3 as an inorganic binder.

This layer consists of B2O32O part, HO22O part, NiO6O part
The mixture was mixed and fired under pressure at 850° C. for 2 hours to obtain glass. This glass was ground to a thickness of 50 microns and used in place of layer 14 with the compound of Example 4. Adhesion to the electrochromic layer was achieved through polystyrene coated in submicron order. The display panel thus obtained was as effective as Example 4.

[Brief explanation of the drawing]

FIG. 1 is an X-ray display panel showing one embodiment of the present invention.

Claims (1)

[Scope of Claims] 1. An X-ray sensitive photoconductive material characterized by having a compound represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, M is Mo, W, Mn, Ni, Co, Rh, Ir.
, a transition metal element selected from Cu and Ag, X is V
Group Ib element, k, l, m and n are positive integers, k
There is a relationship l=mn. )2 An X-ray sensitive photoconductive material comprising the compound according to claim 1 and a substance whose optical properties electrically change.