JPH06332200A - Image reading element - Google Patents

Abstract

PURPOSE:To provide the element which has a high sensitivity and high light response speed, is less deteriorated by fatigue in continuous use and has always stable image reading performance by incorporating a specific photoconductive material into a photoconductive layer. CONSTITUTION:The photoconductive layer 6a is formed by depositing the photoconductive material consisting of the compd. expressed by formula I or formula II by evaporation at a prescribed thickness. In the formulas I, II, A, A', B denote atom groups necessary for forming substd. or unsubstd. arom. rings. The implantation of holes is blocked by a hole implantation blocking layer 7a on an ITO transparent electrode 9a side. The implantation of electrons is blocked as well on a vapor deposited gold counter electrode 5a side as gold has a large work polar number and P type CTM is incorporated into the layer (a). Then, the element of small dark current is obtd. In addition, the compds. of the formulas I, II having excellent photoelectric conversion characteristics are obtd. as the photoconductive material of the layer 6a and, therefore, the element which is large in the photocurrent at the time of photoirradiation, has the high sensitivity, high photoresponsiveness and excellent S/N and is less deteriorated by fatigue in many times of use is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading element used in an image sensor for converting image information into an electric signal and outputting the electric signal to an image forming apparatus, and more particularly to an organic photoconductive material. The present invention relates to an image reading element used as a photoelectric conversion material.

[0002]

2. Description of the Related Art Conventionally, an image sensor has been widely used as a means for reading image information in information communication or information processing, and is widely used as a means for reading image information in, for example, facsimiles, word processors, electronic file systems, copying machines, printers and the like. Has been converted. As the reading element for the image sensor,
Conventionally, a charge-coupled device using crystalline silicon has been known, but a manufacturing technique is difficult and only a small area device can be manufactured. Therefore, a reduction optical system is essential for use.
Therefore, there are problems that the manufacturing cost of the element is high and the recording accuracy is poor.

Therefore, a method of using an organic photoconductive material, which is capable of easily forming a device having a large area, has been studied, in which film formation of the device is achieved by coating or vapor deposition from a coating solution.

For example, JP-A-61-285262 and JP-A-61-2916
No. 57 and Japanese Patent Application Laid-Open No. 1-184961 propose image reading elements using an azo pigment in the photoconductive layer.
An image reading device using a titanyl phthalocyanine pigment is proposed in JP-A-4-63476.

[0005]

However, the above-mentioned known image reading device using an organic photoconductive material has not yet obtained sufficient sensitivity and response speed, and the photoconductive layer is continuously used. However, there were many problems such as fatigue deterioration resulting in an increase in dark current and a decrease in the ratio of photocurrent to dark current, that is, the S / N ratio.

An object of the present invention is to provide an image reading element for an image sensor which has a high sensitivity, a high optical response speed, little fatigue deterioration even during continuous use, and a stable image reading performance.

[0007]

In the image reading device having a transparent electrode, a counter electrode, and a photoconductive layer provided between these electrodes, the above-mentioned object is achieved by using the general formula (1) in the photoconductive layer. ) Or (2), a photoconductive substance composed of a nitrogen-containing heterocyclic compound.

[0008]

[Chemical 2]

[In the formula, A, A ', and B each represent an atomic group necessary for forming a substituted or unsubstituted aromatic ring. The object of the present invention is also achieved by each of the following image reading elements having a selected layer constitution.

First, an object of the present invention is to provide a hole injection blocking layer, which is optionally provided on a transparent electrode, a photoconductive substance comprising a compound represented by the above general formula (1) or (2), and optionally a P-type. Alternatively, a photoconductive layer containing an N-type charge transport substance (hereinafter sometimes abbreviated as CTM) and a counter electrode are laminated in this order, and a negative voltage is applied to the counter electrode with respect to the transparent electrode. It is achieved by an image reading device characterized by being used as a device.

Further, the above object is to provide an electron injection blocking layer, which is optionally provided on a transparent electrode, a photoconductive substance comprising a compound represented by the above general formula (1) or (2), and optionally an N type or A photoconductive layer containing a P-type charge transport material and a counter electrode, which are laminated in this order,
This is achieved by an image reading element characterized in that a positive voltage is applied to the counter electrode with respect to the transparent electrode for use.

Further, the above object is to provide a hole injection blocking layer provided on the transparent electrode, if necessary, and the above-mentioned general formula (1).
Alternatively, a photoconductive layer containing a photoconductive substance composed of the compound represented by (2), a charge transport layer containing a P-type charge transport substance (hereinafter sometimes abbreviated as CTL), and a counter electrode are formed. This is achieved by an image reading element characterized by being laminated in order and applying a negative voltage to the counter electrode with respect to the transparent electrode.

Further, the above object is to provide a photoconductive layer containing a photoconductive substance composed of a compound represented by the general formula (1) or (2) and an electron injection blocking layer provided on the transparent electrode as necessary. And a charge-transporting layer containing an N-type charge-transporting substance and a counter electrode laminated in this order, and a positive voltage is applied to the counter electrode with respect to the transparent electrode for use. This is achieved by the image reading device.

Further, the above object is to provide a charge transport layer containing a P-type charge transport material on a transparent electrode, and the above general formula (1).
Alternatively, a photoconductive layer containing a photoconductive substance composed of the compound represented by (2), a hole injection blocking layer optionally provided, and a counter electrode are laminated in this order, and This is achieved by an image reading element characterized in that a positive voltage is applied to the counter electrode for use.

Further, the above object is to provide a charge transport layer containing an N-type charge transport material on a transparent electrode, and the above general formula (1).
Alternatively, a photoconductive layer containing a photoconductive substance composed of the compound represented by (2), an electron injection blocking layer provided if necessary, and a counter electrode are laminated in this order, and the phototransparent layer is formed on the transparent electrode. This is achieved by an image reading element characterized in that a negative voltage is applied to a counter electrode for use.

[0016]

The operation of the image sensor incorporating the image reading element will be outlined below with reference to FIGS.

FIG. 1 is a sectional view of a vapor deposition type line sensor. An original 4 traveling in the direction of an arrow is irradiated with illumination light from a light source 3, and the image light is a sensor through a rod lens array 2. The image reading element 1 is irradiated,
It is converted into a signal current or a signal charge according to the intensity of light.
The signal current or the signal charge is sequentially output in time series to an exposure device of an image forming apparatus, such as a halogen lamp or a light emitting diode, through a counter electrode composed of individual electrodes arranged in a line for each pixel. Image exposure is performed by controlling the exposure device.

FIG. 2 shows the types of types in which the signal from the element 1 is taken out in time series. FIG. 2A is a photocurrent type in which the signal current obtained by photoelectric conversion is read out as it is. 2 (b) is a charge storage type in which signal charges obtained by photoelectric conversion are stored in a capacitor and read out. When high sensitivity characteristics are required, the charge storage type in FIG. 2 (b) is advantageous. is there.

By the way, when the image reading device is used for an image sensor, in order to fully exhibit its performance,
The following characteristics are required.

(1) A photocurrent of at least 10 ² to 10 ⁴ nA (1 nA / dot) or more per 10 mm ^{2 of} an element should flow when light is irradiated with a sample surface illuminance of 100 Lux under a low voltage of several V to several tens of V. That is, it has high sensitivity characteristics.

(2) The dark current is extremely small in an electric field of at least one polarity, and the ratio of photocurrent to dark current (S /
N ratio) is 10 times or more.

(3) The photocurrent rises rapidly during light irradiation, and when light is interrupted, the photocurrent immediately returns to its original state.
That is, it has an excellent response speed.

FIG. 3 (a), (b), (c) and FIG.
(D), (e) and (f) show the layer structure of the image reading element selected in consideration of the above characteristics.

FIG. 3A shows a structure in which a hole injection blocking layer 7a, a photoconductive layer 6a, and a counter electrode 5a having a large work function are provided in this order on a transparent electrode 9a having a large work function. It is an element that operates by applying a voltage to the transparent electrode 9a that makes the counter electrode 5a side negative. The transparent electrode 9a is, for example, indium oxide, tin oxide, indium oxide-tin oxide (IT) having a relatively large work function on a glass plate 8 which is a transparent support such as glass or quartz.
A metal oxide such as O) or a thin film of nickel-palladium, gold, platinum or the like is provided by vapor deposition or sputtering, and is usually the ITO electrode.

Since the hole injection blocking layer 7a has a relatively large work function, the transparent electrode 9a has a relatively large work function.
It is for preventing injection of holes from the transparent electrode to prevent an increase in dark current, and preferably 10 ⁶ to 10 ¹⁴ Ω.
A resin having a resistivity of about cm is used.

Examples of the resin include polyvinyl alcohol, polyamide, carboxymethyl cellulose,
Ethyl cellulose, polyvinyl butyral, ethylene-
Vinyl acetate copolymer, ethylene-vinyl acetate-maleic anhydride copolymer, other electrophotographic binder resins, or those containing an electron-accepting substance for forming a hole injection blocking layer are used. Polyamides are particularly preferably used.

Next, the photoconductive layer 6a provided on the hole injection blocking layer 7a is formed by depositing a photoconductive substance composed of the compound represented by the general formula (1) or (2) to a thickness of 0.1 to 10 μm. A solution of an organic solvent in which a photoconductive substance formed or formed of the compound represented by the general formula (1) or (2) and a P-type charge transport substance (P-type CTM) are dissolved in a binder resin. It is dissolved and dispersed in the solution, and the resulting dispersion is applied and processed to give a dry film thickness of 0.1 to 10 μm. Next, the counter electrode 5a provided on the photoconductive layer 6a is used as an individual electrode for each pixel, and nickel, palladium, gold, platinum or the like having a relatively large work function is used. Here, gold is deposited or sputtered. It is used as a gold electrode.

Thus, on the ITO transparent electrode 9a side of the device of FIG. 3A, hole injection is prevented by the hole injection blocking layer 7a, and on the gold vapor deposition counter electrode 5a side, gold has a large work function. Also, since the photoconductive layer 6a contains P-type CTM, electron injection is also blocked.
Therefore, a device having an extremely small dark current can be obtained, and the compound represented by the general formula (1) or (2), which is particularly excellent in photoelectric conversion characteristics, is used as the photoconductive substance of the photoconductive layer 6a. A device having a large photocurrent at the time of irradiation, a high sensitivity, a large photoresponsiveness, an excellent S / N ratio, and a large number of uses and less fatigue deterioration can be obtained.

Next, FIG. 3B shows an element having a layer structure similar to that of FIG. 3A, except that the hole injection blocking layer 7a and the ITO transparent electrode 9a having a large work function shown in FIG. ,
Instead of each of the gold vapor deposition counter electrodes 5a, an electron injection blocking layer 7b, an aluminum transparent electrode 9b having a small work function, and an aluminum counter electrode 5b are provided. In the device of FIG. 3B, the photoconductive layer 6b contains an N-type charge transport material (N-type CTM) together with a photoconductive material composed of the compound represented by the general formula (1) or (2), and the voltage is The polarity of application is reversed, and a positive voltage is applied to the counter electrode 5b with respect to the transparent electrode 9b for use.

The electron injection blocking layer 7b is for preventing the injection of electrons from the aluminum transparent electrode 9b having a small work function to prevent the dark current from increasing, and is preferably 10 ⁶ to 10 ¹⁴ Ω. A resin having a resistivity of about cm is used. Examples of such resins include ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-vinyl acetate-maleic anhydride copolymer, melamine resin, phenol resin, polyvinyl chloride, polyamide and other electrophotographic materials. A binder resin or a resin containing an electron donating substance for forming an electron injection blocking layer is used, and an ethylene copolymer is particularly preferably used.

Thus, in the device of FIG. 3B, the injection of electrons from the aluminum transparent electrode 9b having a small work function to the photoconductive layer 6b is blocked by the electron injection blocking layer 7b. Further, the counter electrode 5b is made of aluminum having a small work function, and the photoconductive layer 6b is made of N-type C.
Since TM is contained, holes are prevented from being injected from the counter electrode 5b, so that a high-performance image reading device with a small dark current and a large photocurrent can be obtained as in FIG.

Next, the device of FIG. 3C is a photoconductive layer containing a photoconductive substance composed of the compound represented by the general formula (1) or (2) on the aluminum vapor-deposited transparent electrode 9b having a small work function. 6 and CTL11a containing P-type CTM
And a counter electrode 5a of gold vapor deposition having a large work function are provided in this order, and a negative voltage is applied to the counter electrode 5a with respect to the transparent electrode 9b for use.

Thus, the transparent electrode 9a of the element shown in FIG.
On the side, since the electrode 9a is made of aluminum having a small work function, and the photoconductive substance made of the compound represented by the general formula (1) or (2) of the photoconductive layer 6 is N type. In particular, hole injection is blocked without providing a hole injection blocking layer. On the side of the counter electrode 5a in FIG. 3C, electron injection is blocked because the electrode is vapor-deposited with a large work function and the CTL 11a is a layer containing P-type CTM. So Figure 3
Similar to the cases (a) and (b), a high-performance image reading device with a small dark current and a large photocurrent can be obtained.

Next, the device of FIG. 4D has a layer structure similar to that of FIG. 3C, but contains the aluminum-deposited transparent electrode 9b of FIG. 3C and a P-type CTM. CTL
11a, instead of the counter electrode 5a of gold vapor deposition, IT
An O transparent electrode 9a, a CTL 11b containing N-type CTM, an aluminum-deposited counter electrode 5b are provided, and a photoconductive layer 6a is provided with a photoconductive substance made of a compound represented by the general formula (1) or (2). A P-type CTM is included.

The voltage applied to the device of FIG.
The polarity is reversed, and a positive voltage is applied to the counter electrode 5b with respect to the transparent electrode 9a for use.

Thus, the transparent electrode 9b of the element shown in FIG.
On the side, the electrode is made of ITO with a large work function,
Since the photoconductive layer 6a contains P-type CTM,
The injection of electrons is blocked. On the side of the counter electrode 5b of the device of FIG. 4D, hole injection is blocked because the electrode has a small work function and the CTL 11b contains an N-type CTM. As in the case of (c), a high-performance image reading device with a small dark current and a large photocurrent can be obtained.

In the elements of FIGS. 3C and 4D, no hole or electron injection blocking layer is used in the layer structure, but in the element of FIG. 3C, transparent aluminum vapor deposition is used. When the ITO transparent electrode 9a is used instead of the electrode 9b, it is preferable to provide a hole injection blocking layer between the electrode 9a and the photoconductive layer 6.

In the device of FIG. 4D, when the ITO transparent electrode 9a is replaced by a transparent aluminum electrode 9b having a small work function, the transparent electrode 9b and the photoconductive layer 6a are formed.
It is preferable to provide an electron injection blocking layer between and.

Next, the device of FIG. 4 (e) is a CTL containing P-type CTM on the ITO transparent electrode 9a having a large work function.
11a, a photoconductive layer 6 containing a photoconductive substance composed of a compound represented by the general formula (1) or (2), a hole injection blocking layer 7a, and a counter electrode 5a of gold vapor deposition having a large work function.
Are provided in this order, and a positive voltage is applied to the counter electrode 5a with respect to the transparent electrode 9a for use.

Thus, the transparent electrode 9a of the element shown in FIG.
On the side, the electrode has a large work function, and CTL11
Since a is a layer containing P-type CTM, electron injection is blocked. Further, since the hole injection blocking layer 7a is provided on the counter electrode 5a side of the element of FIG.
As in the case of (c) and FIG. 4 (d), a high-performance image reading device with a small dark current and a large photocurrent can be obtained.

Next, the element shown in FIG. 4F has a layer structure similar to that of the element shown in FIG. 4E, but I of the element shown in FIG.
TO transparent electrode 9a, CTL11a containing P-type CTM,
Instead of the hole injection blocking layer 7a and the gold-deposited counter electrode 5a, an aluminum-deposited transparent electrode 9b and an N-type C
CTL11b containing TM, electron injection blocking layer 7
b, a counter electrode 5b of aluminum vapor deposition is provided.

Thus, the transparent electrode 9b of the element shown in FIG.
On the side, the electrode has a low work function, and CTL11
Since b is a layer containing N-type CTM, hole injection is blocked. In addition, since the electron injection blocking layer 7b is provided on the counter electrode side of the element of FIG. 4F, the injection of electrons is blocked, and FIG.
Similar to the cases of (c) and FIGS. 4 (d) to (e), a high-performance image reading device with a small dark current and a large photocurrent can be obtained.

The structure of the photoconductive layer used in each of the image reading elements of FIGS. 3 and 4 of the present invention will be described in more detail below.

The photoconductive layer is formed by, for example, 10 ⁻³ by a vapor deposition method.
General formula (1) or (2) in a vacuum deposition chamber of ~ 10 ^-4 mmHg
A photoconductive substance composed of a compound represented by
May be formed by vapor deposition under heating, or a binder resin containing a photoconductive substance composed of the compound represented by the general formula (1) or (2) in a solution of an organic solvent in which a binder resin is dissolved. 10 to 10,000 parts by weight per part by weight, or if necessary, P-type CTM or N-type CTM
It may be formed by applying a coating solution containing 0 to 100 parts by weight per 100 parts by weight of a binder resin by a known coating means.

The nitrogen-containing heterocyclic compound represented by the general formula (1) or (2) useful in the present invention is specifically classified into the following four groups.

[0046]

[Chemical 3]

The compound of the present invention has the following reaction formula (1):
Alternatively, each can be synthesized according to (2).

[0048]

[Chemical 4]

A more preferable example of the compound of the present invention is the case where B is perylene in the above general formula (1), which is represented by the following general formula (3) or (4).

[0050]

[Chemical 5]

[In the formula, A represents an atomic group necessary for forming a substituted or unsubstituted aromatic ring. Preferred examples of A include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a pyridine ring, a pyrimidine ring, a pyrazole ring and an anthraquinone ring, and particularly preferred are a benzene ring and a naphthalene ring.

Further, as the substituent of A, alkyl,
Examples thereof include alkoxy, aryl, aryloxy, acyl, acyloxy, amino, carbamoyl, halogen, nitro and cyano.

These derivatives are X-rays for Cu-Nα radiation.
In the line diffraction spectrum, the black angle 2θ is 6.3 ° ±
0.2 °, 12.5 ° ± 0.2 °, 25.4 ° ± 0.2 °, 27.0 ° ± 0.2 °
Those having a peak at are preferable.

Specific compounds of the above-mentioned perylene derivative include those described in Japanese Patent Application No. 4-127457, for example:

[0055]

[Chemical 6]

[0056]

[Chemical 7]

On the other hand, examples of specific compounds of the general formula (1) that are not included in the general formula (3) or (4) include, for example, the following.

[0058]

[Chemical 8]

[0059]

[Chemical 9]

The following are specific examples of the compound represented by the general formula (2).

[0061]

[Chemical 10]

Next, FIG. 3 (c) and FIG. 4 (d) of the present invention.
To (f) CTL containing P-type CTM or CTL containing N-type CTM is 10 to 10000 parts by weight of the P-type or N-type CTM together with a binder resin per 100 parts by weight of the binder resin. It can be obtained by dissolving in, and applying and drying the obtained coating solution.

Further, FIGS. 3 (a), (b), FIG. 4 (e),
(F) Hole or electron injection blocking layer 7a or 7
The electron-accepting substance or electron-donating substance contained in b is
It may be N-type CTM or P-type CTM, and is contained in an amount of 0 to 100 parts by weight per 100 parts by weight of the binder resin.

Examples of the P-type CTM include oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, styryl compounds,
Hydrazone compounds, pyrazoline derivatives, oxazolone derivatives, benzothiazole derivatives, benzimidazole derivatives, cazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, poly-N-vinylcarbazole, poly-1-vinylpyrene, poly-9- It may be vinyl anthracene or the like.

Among these CTMs, for example, JP-A-60-1
72044, Japanese Patent Application No. 3-168711, and Japanese Patent Application No. 3-168
The styryl compounds, hydrazone compounds, pyrazoline compounds and amine compounds described in Japanese Patent No. 713 are preferably used. Next, examples of the N-type CTM include "trinitro-indeno-quinoxaline derivative" described in JP-A-52-109938, "trinitro-thioxanthone derivative" described in JP-A-52-77730, and JP-A- "Dinitro-indeno-thiophene derivative" described in JP-A-53-52134, JP-A-53-9
"Dinitro-fluorenone derivative" described in Japanese Patent No. 2749,
Examples thereof include nitro derivatives such as "dinitrobenzotrobon derivative" described in JP-A-51-141631. Moreover, JP-A-63
-Tetracyanoanthraquinone derivative described in JP-A-70257, "Diphenyl-dicyanoethylene derivative" described in JP-A-63-175860, and "N" described in JP-A-2-42449.
A cyano derivative such as "-cyanoimine derivative".

Furthermore, "diphenoquinone derivative" described in JP-A-1-206349, "benzoquinone derivative" described in JP-A-63-241548, "anthraquinone derivative" described in JP-A-61-233750, etc. The quinone derivative of is mentioned.

Next, the photoconductive layers 6, 6a, 6b and P-type C
CTL11a containing TM and C containing N-type CTM
As the binder resin used for TL11b, most of the binder resins for electrophotographic photoreceptors can be used,
For example, polyethylene, polypropylene, acrylic resin,
Methacrylic resin, vinyl chloride resin, vinyl acetate resin, vinyl butyral resin, vinyl formal resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, polycarbonate resin, silicone resin, melamine resin, etc. Addition type resins, polycondensation type resins, and copolymer resins containing two or more of repeating units of these resins, for example, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate
-In addition to insulating resins such as maleic anhydride copolymer resins, polymer organic semiconductors such as poly-N-vinylcarbazole can be mentioned.

Next, as the dispersant for the photoconductive substance of the organic photoconductive layer, the solvent for forming the charge transport layer, and the solvent for forming the hole or electron injection blocking layer, for example, hexane, benzene, Hydrocarbons such as toluene and xylene, methylene chloride, methylene bromide, 1,2-dichloroethane, tetrachloroethane, 1,2-dichloroethylene, 1,1,2-trichloroethane, 1,1,1-trichloroethane , 1,2-dichloropropane, chloroform,
Bromoform, halogenated hydrocarbons such as chlorobenzene, acetone, methyl ethyl ketone, ketones such as cyclohexanone, ethyl acetate, esters such as butyl acetate, methanol, ethanol, propanol, butanol, cyclohexanol, heptanol, ethylene glycol, methyl cellosolve, Ethyl cellosolve, alcohols such as cellosolve acetate and its derivatives, ethers such as tetrahydrofuran, 1,4-dioxane, furan and furfural, acetals, amines such as pyridine and butylamine, diethylamine, ethylenediamine, isopropanolamine, N, N-dimethyl Examples thereof include amides such as formamide.

[0069]

EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1 This example will be described with reference to FIG. ITO prepared by dissolving 2 g of copolymer nylon "Daiamide T171" (manufactured by Daicel) and 0.1 g of the following N-type CTM in 100 ml of n-propanol, and depositing the obtained solution on a glass plate 8 with indium and tin oxide. The hole injection blocking layer 7a was formed on the transparent electrode 9a by dip coating so that the dry film thickness was 0.5 μm. Then, the compound represented by the exemplified compound (G1) was vacuum-deposited to a thickness of 0.5 μm on the hole injection blocking layer 7a under heating at 150 ° C. in a vacuum of 10 ⁻³ mmHg to form a photoconductive layer 6.

Next, gold was vapor-deposited on the entire surface of the photoconductive layer 6 to provide a counter electrode 5a (different from the individual electrode) to obtain a device of this example, and the device was evaluated as follows. . With the counter electrode 5a being negative with respect to the transparent electrode 9a, a voltage of -45 V was applied to this element, and a tungsten light having a sample surface illuminance of 100 Lux was subjected to rectangular repeated exposure with a lighting time of 5 msec and a lighting cycle of 50 msec as shown in FIG. went. Light current at this time is 850nA / 10 mm ^2, the dark current is 8 nA / 10 mm ^2,
The rising time Tr (time to reach 90% of the saturation value) in FIG. 5B is 1.0 msec, and the falling time Td (time to reach 0% before 0 value) is 1.4 msec, which is practical as an element for image sensor. It has been found that it has sufficient performance.

[0072]

[Chemical 11]

Incidentally, the illuminance of the sample surface was measured by Yokogawa Electric.
3281 Measured with a portable illuminometer.

Embodiment 2 This embodiment will be described with reference to FIG. An element of Example 2 was obtained in the same manner as in Example 1 except that the photoconductive layer 6 of Example 1 was replaced by a resin-dispersed photoconductive layer 6a containing P-type CTM and manufactured by coating. It was The photoconductive layer 6a was formed as follows. First, 10 g of Exemplified Compound (G23) was mixed in 100 ml of dimethoxyethane and dispersed for 30 minutes with a sand grinder. A coating solution was obtained by mixing with a solution dissolved in 200 ml.

This coating solution was applied on the hole injection blocking layer 7a shown in FIG. 3A so as to have a dry film thickness of 0.5 μm to obtain a photoconductive layer 6a. The performance of the device of Example 2 obtained here was measured and evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0076]

[Chemical 12]

Embodiment 3 This embodiment will be described with reference to FIG. "Daiamide T171" (2 g) and the following P-type CTM (0.1 g) were dissolved in 100 ml of n-propanol, and a glass plate 8 was vapor-deposited with aluminum to form a transparent electrode 9b. An electron injection blocking layer 7b was formed.
Then, by weight of the exemplified compounds (mixture of G3 and G24)
10 g in 100 ml of dimethoxyethane with a sand grinder
Dispersed for 30 minutes, and 0.1 g of the following N-type CTM and polyvinyl butyral resin (Sekisui Chemical S-REC BH-3) 10
g was mixed with a liquid dissolved in 200 ml of dimethoxyethane to obtain a coating liquid.

This coating solution was applied on the electron injection blocking layer 7b so as to have a dry film thickness of 0.5 μm to obtain a photoconductive layer 6b. Then, aluminum was vapor-deposited on the entire surface of the photoconductive layer 6b to provide a counter electrode 5b to obtain an element of this example.

Using this device, measurement and evaluation were carried out in the same manner as in Example 1 except that a positive voltage was applied to the counter electrode 5b with respect to the transparent electrode 9b, and the results are shown in Table 1.

[0080]

[Chemical 13]

Embodiment 4 This embodiment will be described with reference to FIG. Glass plate 8
A photoconductive layer 6 was formed on the transparent electrode 9b formed by vapor-depositing aluminum as follows. First, the exemplified compound (G
36) 10 g was mixed with 100 ml of 1,2-dichloroethane and dispersed for 30 minutes with a sand grinder, and 10 g of polycarbonate "Panlite L-1250" (manufactured by Teijin Chemicals) was 1,2-
A coating solution was obtained by mixing with a solution dissolved in 200 ml of dichloroethane. A dry film thickness of this coating solution is set on the transparent electrode 9b.
Application processing was performed to obtain a photoconductive layer 6 having a thickness of 6 μm. Then, C containing P-type CTM is formed on the photoconductive layer 6 as follows.
TL11a was formed.

First, the polycarbonate resin "Iupilon Z"
-200 "(manufactured by Mitsubishi Gas Chemical Co., Inc.) 100g and the following P-type CTM10
A coating solution obtained by dissolving 0 g in 100 ml of monochlorobenzene was applied on the photoconductive layer 6 so that the dry film thickness was 0.7 μm to form CTL11a.

Then, gold is vapor-deposited on the entire surface of the CTL 11a to form a counter electrode 5a to obtain the device of this embodiment, and the first embodiment is obtained.
The photocurrent, dark current, rise time Tr and fall time Td were measured in the same manner as in, and the results are shown in Table 1.

[0084]

[Chemical 14]

Embodiment 5 This embodiment will be described with reference to FIG. Glass plate 8
A photoconductive layer 6a was formed on the transparent electrode 9a formed by depositing ITO on the substrate as follows. First, exemplified compound (G74)
10 g was mixed with 100 ml of 1,2-dichloroethane and dispersed for 30 minutes with a sand grinder. This was added with 10 g of polycarbonate "Panlite L-1250" and P-type CTM of Example 4.
A coating solution was obtained by mixing 0.1 g of the solution with the solution. The coating solution was applied to the transparent electrode 9a so that the dry film thickness was 0.6 μm, and the photoconductive layer 6a was obtained. Then, the CTL 11b containing N-type CTM is formed on the photoconductive layer 6a as follows.
Was formed.

First, the polycarbonate resin "Iupilon Z"
-200 "100 g and the following N-type CTM 100 g were dissolved in 1000 ml of monochlorobenzene to obtain a coating solution, which was used as the photoconductive layer 6a.
Apply CTL11 by applying coating so that the dry film thickness becomes 0.7 μm.
b was formed.

Next, aluminum is vapor-deposited on the entire surface of the CTL 11b to form a counter electrode 5b to obtain a device of this embodiment, and a positive voltage is applied to the counter electrode 5b with respect to the transparent electrode 9a. The photocurrent, dark current, rise time Tr, and fall current Td were measured in the same manner as in Example 1, and the results are shown in Table 1.

[0088]

[Chemical 15]

Embodiment 6 This embodiment will be described with reference to FIG. Glass plate 8
A CTL 11a containing a P-type CTM was formed on the transparent electrode 9a formed by vapor-depositing ITO as follows.

First, the acrylic resin "Dynar BR-8
0 "(manufactured by Mitsubishi Rayon Co., Ltd.) and 100 g of the following P-type CTM were dissolved in 1000 ml of monochlorobenzene to obtain a coating solution,
CTL11a was formed by coating on the transparent current 9a so that the dry film thickness was 0.7 μm.

Then, a photoconductive layer 6 was formed on the CTL 11a as follows. First, 10 g of the exemplified compound (G62)
Mix with 100 ml of 1,2-dichloroethane and disperse with a sand grinder for 30 minutes. Add 10 g of linear polyester "Vylon 200" (Toyobo Co., Ltd.) to 200 m of 1,2-dichloroethane.
A coating solution was obtained by mixing with the solution dissolved in 1. The coating solution was applied onto the CTL 11a so that the dry film thickness was 0.5 μm, and the photoconductive layer 6 was obtained. Then, a hole injection blocking layer 7a was formed on the photoconductive layer 6 as follows.
Copolymerized nylon "Dyamide T171" 2g and the following N type C
0.1 g of TM was dissolved in 100 ml of n-propanol, and the resulting solution was applied on the photoconductive layer 6 so that the dry film thickness was 0.5 μm to form the hole injection blocking layer 7a.

Next, gold is vapor-deposited on the entire surface of the hole injection blocking layer 7a to form the counter electrode 5a to obtain the element of this embodiment, and a positive voltage is applied to the counter electrode 5a with respect to the transparent electrode 9a. Measured the photocurrent, dark current, rise time Tr, and fall time Td in the same manner as in Example 1, and the results are shown in Table 1.
It was shown to.

[0093]

[Chemical 16]

Embodiment 7 This embodiment will be described with reference to FIG. Glass plate 8
A CTL 11b containing N-type CTM was formed on the transparent electrode 9b formed by vapor-depositing aluminum as follows. First, a coating solution obtained by dissolving 100 g of acrylic resin "Dianal BR-80" and 100 g of N-type CTM of Example 6 in 1000 ml of monochlorobenzene was applied to the transparent electrode 9b to give a dry film thickness.
Coating processing was performed so as to have a thickness of 0.7 μm to form CTL11b.

Then, a photoconductive layer 6 was formed on the CTL 11b as follows. First, 10 g of the exemplified compound (mixture of G46 and G50 in a weight ratio) was mixed with 100 ml of 1,2-dichloroethane, and dispersed with a sand grinder for 30 minutes, and 10 g of linear polyester "Vylon 200" was 1,2- A coating solution was obtained by mixing with a solution dissolved in 200 ml of dichloroethane. The coating solution was applied onto the CTL 11b so that the dry film thickness was 0.4 μm, and the photoconductive layer 6 was obtained. Then, an electron injection blocking layer 7b was formed on the photoconductive layer 6 as follows. Ethylene copolymer resin "ELVACS
4260 "(manufactured by DuPont) is dissolved in 100 ml of toluene, and the resulting solution is applied onto the photoconductive layer 6 to give a dry film thickness of 0.4.
Electron injection blocking layer 7 by coating so as to have a thickness of μm
b was formed.

Next, aluminum is vapor-deposited on the entire surface of the electron injection blocking layer 7b to form the counter electrode 5b to obtain the device of this example. In the same manner as in Example 1, the photocurrent, dark current, rise time Tr, The fall time Td was measured, and the results are shown in Table 1.

The elements of Examples 1 to 7 were subjected to continuous repeated measurement 100 times.
There was almost no change in the characteristics of.

Comparative Example 1 Similar to Example 2 except that an oxytitanium phthalocyanine pigment was used in place of the exemplified compound (G-2) which is the compound represented by the general formula (1) or (2) of Example 2. Then, an image reading device for comparison was obtained, and the photocurrent, the dark current, and the rise time T were obtained in the same manner as in Example 1 using the device.
The r and the falling current Td were measured, and the results are shown in Table 1. The characteristics of the comparative element were repeatedly measured 100 times, and as a result, a characteristic deterioration of about 20% was observed.

[0099]

[Table 1]

It can be seen from Table 1 that each element of the examples is excellent in photocurrent, dark current, rise time Tr, fall time Td characteristics and durability even when compared with the comparative example.

[0101]

As is apparent from the above description, according to the image reading element of the present invention, the photocurrent is large, the dark current is small, and the rising and falling of the light upon irradiation are fast, and the image reading element is used. As a result, it is possible to obtain an image sensor having high sensitivity, high durability and high performance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a vapor deposition line sensor.

FIG. 2 is a block diagram showing signal reading and paths.

FIG. 3 is a cross-sectional view showing a layer structure of an element.

FIG. 4 is a cross-sectional view showing a layer structure of an element.

FIG. 5 is a diagram showing a change with time of element evaluation test light.

[Description of Reference Signs] 1 image reading element 2 rod lens array 3 light source 4 originals 5a, 5b counter electrode 6 photoconductive layer 6a photoconductive layer containing P-type CTM 6b photoconductive layer containing N-type CTM 7a hole injection blocking layer 7b Electron injection blocking layer 8 Glass plate 9a, 9b Transparent electrode 11a CTL 11b containing P-type CTM CTL 12a, 12b containing N-type CTM DC power supply 13 Output terminal

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication location H01L 27/146 31/0344 H04N 1/028 Z 8721-5C 5/335 U

Claims (17)

[Claims] 1. A transparent electrode irradiated with light, a counter electrode,
In an image reading device having a photoconductive layer provided between these electrodes, the photoconductive layer contains a photoconductive substance composed of a nitrogen-containing heterocyclic compound represented by the general formula (1) or (2). An image reading element characterized by being. [Chemical 1] [In the formula, A, A ', and B each represent an atomic group necessary for forming a substituted or unsubstituted aromatic ring. ] 2. A transparent electrode, a photoconductive layer containing a photoconductive substance comprising the compound represented by the general formula (1) or (2), and a counter electrode, which are laminated in this order,
An image reading element, which is used by applying a negative voltage to the counter electrode with respect to the transparent electrode. 3. A photoconductive substance comprising a compound represented by the general formula (1) or (2) and P on a transparent electrode.
A photoconductive layer containing a positive or N-type charge transport material and a counter electrode are laminated in this order, and a negative voltage is applied to the transparent electrode with respect to the transparent electrode for use. The image reading element according to claim 2. 4. A photoconductive substance comprising a compound represented by the general formula (1) or (2) and N on a transparent electrode.
A photoconductive layer containing a P-type or P-type charge transport material and a counter electrode are laminated in this order, and a positive voltage is applied to the counter electrode with respect to the transparent electrode for use. The image reading element according to claim 2. 5. A photoconductive layer containing a photoconductive substance made of the compound represented by the general formula (1) or (2) and a counter electrode are laminated in this order on a transparent electrode,
An image reading element, which is used by applying a positive voltage to the counter electrode with respect to the transparent electrode. 6. A photoconductive layer containing a photoconductive substance composed of the compound represented by the general formula (1) or (2) on a transparent electrode, and a charge transport layer containing a P-type charge transporting substance. An image reading element comprising a counter electrode and a counter electrode, which are laminated in this order, and a negative voltage is applied to the counter electrode with respect to the transparent electrode. 7. A photoconductive layer containing a photoconductive substance composed of the compound represented by the general formula (1) or (2) on a transparent electrode, and a charge transporting layer containing an N-type charge transporting substance. An image reading element comprising a counter electrode and a counter electrode, which are laminated in this order, and a positive voltage is applied to the counter electrode with respect to the transparent electrode. 8. A charge transport layer containing a P-type charge transport substance on a transparent electrode, and a photoconductive layer containing a photoconductive substance comprising the compound represented by the general formula (1) or (2). An image reading element comprising a counter electrode and a counter electrode, which are laminated in this order, and a positive voltage is applied to the counter electrode with respect to the transparent electrode. 9. A charge transport layer containing an N-type charge transport substance, and a photoconductive layer containing a photoconductive substance comprising a compound represented by the general formula (1) or (2) on a transparent electrode. An image reading element comprising a counter electrode and a counter electrode, which are laminated in this order, and a negative voltage is applied to the counter electrode with respect to the transparent electrode. 10. A hole injection blocking layer on a transparent electrode,
A photoconductive layer containing a photoconductive substance made of the compound represented by the general formula (1) or (2) and a counter electrode are laminated in this order, and a negative electrode is applied to the counter electrode with respect to the transparent electrode. The image reading device according to claim 2, wherein the image reading device is used by applying the voltage of 3. 11. A hole injection blocking layer on a transparent electrode,
A photoconductive layer containing a photoconductive substance composed of the compound represented by the general formula (1) or (2) and a P-type charge transport substance, and a counter electrode are laminated in this order. 11. The image reading element according to claim 10, wherein a negative voltage is applied to the counter electrode for use. 12. An electron injection blocking layer on a transparent electrode, and a photoconductive layer containing a photoconductive substance composed of the compound represented by the general formula (1) or (2) and an N-type charge transporting substance, 12. The image reading element according to claim 11, wherein a counter electrode is laminated in this order, and a positive voltage is applied to the counter electrode with respect to the transparent electrode for use. 13. An electron injection blocking layer, a photoconductive layer containing a photoconductive substance composed of the compound represented by the general formula (1) or (2), and a counter electrode on a transparent electrode in this order. The image reading element according to claim 3, wherein the image reading element is formed by stacking layers and is used by applying a positive voltage to the counter electrode with respect to the transparent electrode. 14. A hole injection blocking layer on a transparent electrode,
A photoconductive layer containing a photoconductive substance composed of the compound represented by the general formula (1) or (2), a charge transport layer containing a P-type charge transport substance, and a counter electrode are laminated in this order. The image reading device according to claim 4, wherein a negative voltage is applied to the counter electrode with respect to the transparent electrode for use. 15. An electron injection blocking layer, a photoconductive layer containing a photoconductive substance composed of the compound represented by the general formula (1) or (2), and an N-type charge transporting substance on a transparent electrode. 6. The image reading element according to claim 5, wherein the charge transport layer containing therein and the counter electrode are laminated in this order, and a positive voltage is applied to the counter electrode with respect to the transparent electrode for use. . 16. A charge transport layer containing a P-type charge transport substance on a transparent electrode, and a photoconductive layer containing a photoconductive substance comprising the compound represented by the general formula (1) or (2). 7. The image reading device according to claim 6, wherein a hole injection blocking layer and a counter electrode are laminated in this order, and a positive voltage is applied to the counter electrode with respect to the transparent electrode for use. . 17. A charge transport layer containing an N-type charge transport substance, and a photoconductive layer containing a photoconductive substance comprising the compound represented by the general formula (1) or (2), on a transparent electrode. 8. An image reading device according to claim 7, wherein the electron injection blocking layer and the counter electrode are laminated in this order, and the transparent electrode is used by applying a negative voltage to the counter electrode. .