JPH01184961A - Image sensor - Google Patents

Abstract

PURPOSE:To enable the production of an image sensor that is as large as a text and therefore is directly readable by a method wherein the photoconductive film of a photosensitive element is built of a specified disazo compound and a specified hydrazone compound. CONSTITUTION:The photoconductive film of a photosensitive element is com posed of a disazo compound represented by a formula l and a hydrazone com pound represented by a formula II. Such a photoconductive film mainly com posed of an azo pigment and a hydrazone compound may be used as a photosen sitive element photoconductive material because it is higher in responding speed than a film that is mainly composed only of an azo pigment and because the mobility of carriers therein is higher. In the formulas illustrated, the A represents a formula III or IV; the X an aromatic compound or a hetero-ring, or its substitution product; the Ar1 an aromatic compound or a hetero-ring, or its substitution product; the Ar2 an aromatic compound or its substitution product; R1-R3 hydrogen, a lower alkyl group, and a phenyl group, or their substitution products; and R4 a lower alkyl group or a phenyl group or a carboxyl group, or its ester.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an image sensor, and more particularly to an image sensor constructed by providing at least individual electrodes, a common electrode, and a photosensitive element on an insulating substrate.

[Conventional technology]

Image sensors that use photoconductive materials for their photosensitive elements are compact and highly reliable, and are easy to reduce in price due to the quantity reduction effect, so they are widely used in =*h capture devices in facsimile machines, etc. .

Conventionally known photosensitive elements include CdS
, JP-A-59-54373 (JPYL Corporation), JP-A-59-1 as a photosensitive element using amorphous-8l
12651 (Fujitsu), JP-A-59-110177 (
Toshiba), etc., and a photosensitive element using P-C-St is Tokuhan Sho 58-118161 (Canon). [Nikkei Electronics J (April 26, 1982)] introduces photosensitive elements using CdSehSs-Am-Te, etc. in addition to the above-mentioned CdS and amorphous-81.

[Problem that the invention seeks to solve]

However, in image sensors using the above-mentioned photoconductive materials, it is difficult to fabricate a large photosensitive element due to film formation methods, photosensitive characteristics, etc., and a moving small lens is required for FA phase reading. There is a problem in that the size of the entire image reading device increases in order to secure the distance.

[Means for solving problems]

The present inventors have conducted extensive research on photoconductive materials for photosensitive elements using azo pigments in order to create image sensors with the width of a manuscript that can be directly read. The Hikari 4M film has greater carrier movement and concealment than the one whose main component is azo pigment alone, improves response speed, reduces S/N ratio during repeated use, and improves optical memory characteristics under heavy exposure. The present invention was achieved by discovering that it can be modified and suitably used as a photoconductive material for photosensitive elements.

That is, the image sensor of the present invention is an image sensor configured by providing at least individual electrodes, a common electrode, and a photosensitive element on an insulating substrate, in which the photosensitive element has a general formula; however, in the general formula, Here, X represents an aromatic group such as a benzene ring or a naphthalene ring, a hetero group such as an indole ring, a carbazole ring, or a dibenzofuran ring, or a substituted product thereof.
rz represents an aromatic group such as a benzene ring or a naphthalene ring, or a hetero group such as a dibenzofuran ring, or a substituted product thereof; R,,R
2, R represents hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof, R4 represents a lower alkyl group, a phenyl group, and Cal represents a xyl group or an ester thereof]
At least one disazo compound represented by the general formula [However, in the above general formula, Ar2 is a benzene ring.

A hydrazone represented by a naphthalene ring, an anthracene ring, a styryl group, or a substituted product thereof or a carbazole ring indole-broken, R5 and R6 represent an alkyl group, an aryl group, or a benzyl group, and R6 forms a ring with a benzene ring. It is defined as "t%" to have an optically exclusive FL film containing one of the compounds as an active ingredient.

Prior to explaining the image sensor of the present invention, the configuration of an image reading device using the image sensor of the present invention will be explained.

FIG. 2 is a schematic configuration diagram showing an example of an image reading device using the image sensor of the present invention.

As shown in the figure, the image reading device of this example has an illumination light source 2.
, a rod lens array 4 as a guide thread, an image sensor 3t having photosensitive elements arranged in an array, and a readout circuit and a set meal circuit (not shown) are required to drive the image sensor.

The light emitted from the illumination light source 2 is reflected off the original 1, passes through the rod lens array 4'Ik, and is irradiated onto the image sensor 3. Information on the original a1 is read out from the image sensor 3 using a readout circuit, and there are two readout methods: a real-time method and a charge accumulation method.

FIG. 3(4) is a circuit diagram showing an example of a real-time type readout circuit, and FIG. 3(B) is a circuit diagram showing an entire example of a charge accumulation type readout circuit.

In FIG. 3 (4), the cathode of a blocking diode 9 is connected in series to one side of each photosensitive element 11 of the image sensor 3, and the changeover switch 10 is individually connected to the other side through the pole 8. The anode side is connected to the common electrode 7. The common electrode 7 has a power supply 5, a load resistor 6,'F
! It is commonly connected to the other switch 10 via the L flow detection means 12 .

In the real-time method, the change-over switch 10 is sequentially switched according to the above-mentioned circuit configuration to convert a change in resistance of the photosensitive element 11 into a change in current, which is then output as a photoelectric conversion output signal by the current detection means 12.

In FIG. 3 (i19), one side of each photosensitive element 11 of the image sensor 3 is connected to a series resistor 6 and a power supply 5 via a common electrode 7, and the other side of each photosensitive element 11 is connected to a capacitor 1.
41? and the drain of the field effect transistor 13. ff-) of the field effect transistor 13 is connected to the scanning circuit 15, and the source is commonly connected to the current detection means 12.

In the charge storage method, the charge accumulated in the capacitor 14 is
The field effect transistor 13'e is connected by the scanning circuit 15.
llim order switching, the discharge current from the capacitor 14 is extracted as a photoelectric conversion output signal by the current detection means.

Next, the configuration of the image sensor of the present invention will be explained.

FIGS. 1(4) to 10) are schematic partial configuration diagrams for explaining an example of the configuration of an image sensor according to the present invention.

As an example of the configuration of the optical element of the photosensitive element, a single layer type is shown in Figure 11 (B), and a laminated type is shown in Figure 1 (C) (2).

The single layer method is used when the photoconductive material based on the present invention is dispersed and formed in the same photoconductive layer 16.

In the lamination method, the photoconductive material according to the present invention is layered with different composition ratios, materials, etc. for each photoconductive layer (here, the first photoconductive layer 16& and the second photoconductive layer 16b). It is used when forming.

The structure of the photosensitive element includes the planar type shown in FIG. 1(4)(C) and the sandwich type shown in FIG. 1CB)(rho). In the sandwich method, an insulating substrate 18
On the top, the optical 4'RL layer 16 or the photoconductive layer 16a is provided between the upper electrode 17m and the lower layer 11L pole 17b.

The sandwich method has the advantage that the inter-electrode spacing can be easily controlled with high accuracy because the thickness of the original layer is the electrode spacing.

On the other hand, the planar one-way method simultaneously forms the electrode 17 on the insulating substrate 18, which has better pinhole resistance than the sandwich method, and can simplify the process because the electrode Q can be created in one step. There are advantages.

Next, the materials and formulations constituting the photosensitive element, which are the characteristics of the present invention, will be explained.

The insulating substrate used in the image sensor of the present invention includes:
For example, when receiving light from the substrate side, use transparent glass,
Use ceramic, plastic or a combination of all of these. In addition, the light 2s formed on the substrate 91
The light beam t# 11 irradiated with light may be a non-light-transmitting insulating substrate, or may be a non-insulating substrate such as metal that is insulated.

Individual electrodes for driving sensors installed on an insulating substrate,
Examples of the common electrode include At, Ti, and V.

Cr, Mn, Fe, Co, Ni,
Cu, Zn, Pb, Sn, Ag,
Au.

Metal films such as Mo and W, alloy films of these metals, and multilayer films of two or more of these metals and alloys are used. If necessary, a translucent RL film of ITO, In2O, etc. is used. It will be done.

These four-electrode films are formed by a sputtering method, a vapor deposition method, a CVD method, or the like, and after the film formation, they are formed into an electrode of a desired shape by a photoetching method or the like.

It is also possible to form the electrodes by the industrially well-known mask evaporation method, screen indori method, lift-off method, etc.

The thickness of the conductive film is preferably 0.001 μm to 10 μm, more preferably 0.01 μm to 5 μm.

In the case of the so-called planar type in which the individual electrodes and the common electrode are installed flatly on the substrate (Fig. 1 (4), Fig. 1 (illustrated in Q), the electrodes are laminated after forming the photoconductive layer on the insulating substrate. Fabricate an image sensor using
The so-called sandwich structure is laminated with a photoconductive lower abdominal electrode (
In the case of FIG. 3 (shown in Figure 3), the lower electrode is formed, then the optical 4m film is formed, and then the upper electrode is laminated using the materials and method described above to form an image sensor. Create. The materials of the upper and lower electrodes do not need to be the same, and are preferably materials that do not interfere with the properties of the photoconductive layer.

Yuanbu X Belly contains an insulating resin and a disazo diverticulate and hydrazone compound having the above general formula as all active ingredients.

As already explained, the photoconductive layer contains a cis-sazo pigment and a hydrazone compound dispersed in a resin, a single-layer system in which the photoconductive layer contains a cis-sazo pigment and a hydrazone compound dispersed in a resin, and a disazo pigment layer in which the photoconductive layer contains a cis-sazo pigment dispersed in a resin. s[N
! A photoconductive layer having one type of configuration or the like is possible.

Examples of the insulating resin used for the light guide film include:

Epoxy resin, acrylic resin, styrene resin, polyester resin, polycargonate resin, polyarylate resin, polyamide resin, polyimide resin, butyral resin,
Examples include benzal resin, which is selected based on film-forming properties, electrical properties as a photosensitive element, etc. Furthermore, in order to compensate for the characteristics of these resins, it is also possible to use two or more insulating resins, or to mix all of plasticizers, antioxidants, etc.

When the light guiding film according to the present invention is of a single layer type, the mixing ratio of the disazo pigment and hydrazone compound to the insulating resin used is shown below.

Disazo pigment / hydrazone resin = 175 to 5/1 Hydrazone compound / Insulating resin: 115 to 271 Next, when the photoconductive layer according to the invention is of the &layer type, the disazo pigment, insulating resin and hydrazone used The mixing weight ratio of the compound and the insulating resin is shown below.

Disazo pigment/Insulating resin: 1/10 to 10/1 Hydrazone compound/Insulating resin: V5 to 2/1 If the mixing ratio of disazo pigment and Shidracin compound to insulating #4 fat is too large, the light guide 'vL film Adhesion between the electrode and the insulating substrate deteriorates, resulting in loss of reliability. Also, if it is too small, the light guide rate will be small and it will not be possible to increase the SN ratio (charging current/dark current).

The a thickness of the original 411 group is generally 0.1 to 0.1 in the case of a single layer system.
The thickness is preferably 5 μm, preferably 0.2 to 2 μm. Next, the light guide′
When the IIL film is of a laminated type, the thickness of the disazo pigment dispersed layer is generally 0.01 to 2 μm, preferably 0.05 to 2 μm.
1 μm is good, and the hydrazone compound layer is 0.5 to 5011
m, preferably 1 to 20 μm. Each layer of the photoconductive group can be easily formed by a coating method such as a dipping method, a doctor blade method, a spray method, or a roll coating method.

It is also possible to mix the above-mentioned disazo pigment and hydrazone compound in the light guiding 'tIL film according to the present invention to complement each other's properties. Further, other additives may be added in order to improve and stabilize each m-characteristic. Further, a protective layer for protecting the entire light guide RL layer from exposure and external forces, a light blocking layer having a function of separating bits, etc. can be provided on the photoconductive film. In addition, a new layer is installed between the electrode and insulating substrate and the -yt and exclusive layers in order to improve the insulating basics and the insulating properties of the electrode, and to improve the electrical properties between the photoconductive group and the electrode. It is also possible to do so.

Specific examples of the disazo pigment and hydrazone compound used in the present invention are illustrated below.

Q+ Mountain O4 Mountain Mountain - Mountain
Mountain Mountain Mountain H-
7 CH.

H-18 H-19 [Effects] The image sensor of the present invention described in detail above has a light guide 'I! It is possible to form the L film over a large area, and as a result, it becomes possible to produce a long, same-size image sensor. Furthermore, by using a disazo pigment and a hydrazone compound, an e&sensitive element having an excellent signal to noise ratio of 9, repeated strength, and light resistance can be obtained.

〔Example〕

Next, Examples and Comparative Examples of the present invention will be shown, but the present invention is not limited thereto.

(Example 1) First, polyamide (CM-8000; Toshishiku Co., Ltd.) S
xt part, degenerate bo! J7 Mi)'(EF-30T;
Imperial Chemical Exhibition) 5] 1 Fit Department, Methanol 6 ON'm
Prepare a bath solution of 5n-butyl alcohol 30'N,
Next, this solution was placed on a Mylar substrate as the fourth factor.
The film thickness after drying was 0.2 μm.

Next, 10 parts by weight of a disazo pigment represented by structural formula P-6,
101 parts of a hydrazone compound represented by structural formula H-4,
1,511 parts of a polycarbonate resin (Panrai L-1250; Hibi, manufactured by Ryotaikasei Co., Ltd.) and 65 parts by weight of tetrahydro 7ran were mixed and sufficiently dispersed in a sand mill.

Further diluted with tetrahydrofuran to bring the solid concentration to 21t.
%, and the light guide 1 conversion paint was adjusted.

Next, the polyamide layer was coated on the Mylar substrate on which the entire polyamide layer was formed by a dipping method, and after drying, the film thickness was 5 μm.
An image sensor (AI) of the present invention was obtained.

In this example, the laminated layer 11 of the electrode and photoconductive film is shown in FIG.
4) C] is the opposite.

(Example 2) Disazo compound represented by structural formula P-13 and structural formula H-
The hydrazone compound shown by No. 15 was used, and the others were as in Example 1.
An image sensor (A2) of the present invention was obtained in the same manner as described above.

(Comparative Example 1) As in Example 1, a polyamide layer with a thickness of 0.2 μm was formed on a substrate on which an In2O electrode was formed. Next, disazo pigment 1 shown by structural formula P-6 used in Example 1
01L negative part, polycarbonate Jugetsuji (/4'N Light L-1250; Teijinka & C Co., Ltd.)) 15'N Juto, and 65 pages'it part of Tetrahydrone were mixed and thoroughly dispersed in a sand mill. The mixture was further diluted with tetrahydrofuran, and the solid content was adjusted to 2% by volume to prepare a Kosen-m film paint.

The entire photoconductive film was coated in the same manner as in Example 1, and after drying, N4
A comparative image sensor (A3) was obtained with a thickness of 5 μm.

(Example 3) A substrate having 21 m of Att poles, which are nine individual Ft poles as shown in FIG.

Next, 5N parts of a disazo pigment represented by the structural formula P-10 (BE, -8; manufactured by Tsukiki Kagaku Co., Ltd.) and methyl ethyl keto 7853kjtMI11 were combined and sufficiently dispersed in a sand mill. . Further, the mixture was diluted with methyl ethyl ketone to give a solid content of 4-cents, to prepare a disazo pigment paint.

A disazo pigment paint was applied onto the substrate having the At electrode 21 ai and dried to obtain a 0.1 μm disazo pigment layer.

Next, hydrazone compound 103 represented by structural formula H-15
[Part i1, polycargenate resin (Panrai) L-12
50; Ondai Kasei Co., Ltd. 10mt part, Tetrahydrof 2
Dissolve 50 parts by weight of hydrazone compound paint gold! li
Made by l. This hydrazone compound paint was coated on top of the disazo pigment layer of Zenkyou and dried to form a 5 μm thick hydrazone compound layer. Further, on the hydrazone compound layer, 20 m of In 20s electrodes having a common pole as shown in FIG.

(Example 4) Disazo compound represented by structural formula P-15 and structural formula H-
An image sensor (45)t- of the present invention was obtained in the same manner as in Example 3 except for using the hydrazone compound represented by No. 19.

(Comparative Example 2) In the same manner as in Example 3, a mylar substrate having a ht pole turn was prepared.

A disazo pigment layer is applied as in Example 3.

Hydrazone compound/i&'! Step n20 of Figure 4-b without cloth. A comparison image sensor (A
6) was obtained.

The SN ratio of the image sensor obtained in this way (Motogo style/Anko style) after repeated use 100 times, the SN ratio after 5 minutes of irradiation at 1000 lux under strong exposure, and the photoresponse speed (startup) υ time; Tu fall time; Td) are shown in Tables 1 and 2. However, the device structures of Examples 1 and 2 and Comparative Example 1 are planar type, and the device structure of Example 3゜4 Comparative Example 2 is sandwich type, and the distance between individual electrodes is 10 μm'f.
The membrane thickness is 0.5 μm.

The SN ratio is determined by applying a DC voltage to the element and setting the field strength to 5×1o.
It was expressed as photocurrent/dark current under an electric field of 4v/cm. Also, the photoresponse rate is 5 x 10' V/c+++ according to the charging current waveform (see Figure i5) at the rising time Tu.

Td was determined for 9 hours after falling. Here, as shown in Fig. 5, the rise time Tu is 10% of the maximum photocurrent value of 11.
The fall time Td refers to the time required for the photocurrent to decrease from 90% to 10% of the maximum current value.

The irradiation light weight when measuring both the SN ratio and the optical response speed was 100 lux using a tungsten lamp.

Table 2 In Tables 1 and 2, image sensors A1 and A4 used a single layer system in which a disazo pigment and a hydrazone compound were dispersed in a trWJ layer, but image sensor A3, which does not contain a hydrazone compound. Superior to Muro, highly sensitive S
It was found that it exhibited good N ratio, combing characteristics, and strong light performance.

In particular, a stacked image sensor-Jlii 4,
With A5, a signal-to-noise ratio of 10s was obtained, and the young fruit was well-developed. In terms of response speed, the effect of soybean modification is clear compared to the comparative product of the present invention.1 The effect of using the disazo pigment and hydrazone compound of the present invention as active ingredients is clear.

[Brief explanation of the drawing]

FIGS. 1-3) are the next schematic partial configuration diagrams illustrating an example of the configuration of the image sensor of the present invention. FIG. 2 is a schematic configuration diagram showing an example of an image reading device using the image sensor of the present invention. FIG. 3B is a circuit diagram showing an example of a real-time type readout circuit, and FIG. 3CB) is a circuit diagram showing an example of a charge storage type readout circuit. FIG. 4(5)) is a schematic plan view showing a play-like configuration of the image sensor of the present invention. The fifth factor is a slope diagram of the original current under an electric field of 5×10'V/'cy++. DESCRIPTION OF SYMBOLS 1... Original, 2... Light source, 3... Image sensor-14... Rod lens array, 5... Power supply, 6...
...Load resistance, 7...Common electrode, 8...Individual electrode,
9... Blocking diode, 10... Switch, 11... Photosensitive resistor, 12... Current detection means, 13
... Field effect transistor, 14... Capacitor, 15... Scanning circuit, 16, 16 a, 16
b---Photoconductive layer, 17--electrode, 17m--upper electrode, 17b--lower electrode, 18--insulating substrate,
19-:/lS=m membrane, 20,21.20a...arch n2
0. Electrode, 21m...At electrode. Agent: Patent Attorney Hiro Yamashita Figure 1 Old Figure 2 Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) In an image sensor configured by providing at least individual electrodes, a common electrode, and a photosensitive element on an insulating substrate, the photosensitive element has a general formula ▲ a mathematical formula, a chemical formula, a table, etc. ▼ [However, the above general formula In, A represents ▲There are mathematical formulas, chemical formulas, tables, etc.▼ or ▲There are mathematical formulas, chemical formulas, tables, etc.▼. Here, X represents an aromatic ring such as a benzene ring or a naphthalene ring, a hetero ring such as an indole ring, a carbazole ring, or a dibenzofuran ring, or a substituted product thereof;
r represents an aromatic ring such as a benzene ring or a naphthalene ring, or a hetero ring such as a dibenzofuran ring, or a substituted product thereof; Ar2 represents an aromatic ring such as a benzene ring or naphthalene ring or a substituted product thereof; R1, R2 ,R
3 represents hydrogen, a lower alkyl group, a phenyl group, or a substituted product thereof, and R4 represents a lower alkyl group, a phenyl group,
represents a carboxyl group or an ester thereof] and the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ [However, in the above general formula, Ar2 is a benzene ring, a naphthalene ring, an anthracene ring, represents a styryl group or a substituted product thereof, or a carbazole ring or an indole ring, R5 and R6 represent an alkyl group, an aryl group, or a benzyl group, and R6 forms a ring with a benzene ring. An image sensor characterized by having a photoconductive film containing as an active ingredient. (2) The image sensor according to claim 1, wherein the photosensitive element has a photoconductive film containing a disazo pigment and a hydrazone compound dispersed in the same layer. (3) A photoconductive film according to claim 1, which has a photoconductive film constituted by a laminated structure of a disazo pigment layer containing a disazo pigment in which a photosensitive element is dispersed and a hydrazone compound layer containing a dispersed hydrazone compound. image sensor.