JPH02155270A - Image sensor - Google Patents

Abstract

PURPOSE:To make it possible to form an image sensor having a large area at a low cost by constituting an optoelectronic transducer part by using an organic optical conductor incorporating an electric-charge generating agent and an electric-charge transfer agent. CONSTITUTION:As an electric-charge generating agent, various kinds of pigments can be used. As an electric charge transfer agent, especially polysilane compound is desirable. A rear surface metal electrode 4 comprising aluminum is formed on a glass substrate 1 by an evaporating method. Then, polyvinyl butyral resin and benzine based disazo pigment are dispersed in solvent. The dispersed liquid is applied on the electrode 4 and dried, and an electric-charge generating layer 5 is formed. Polymethylphenylsilane solution is applied and dried on the electric- charge generating layer 5, and an electric-charge transfer layer 6 is formed. Thus an organic optical conductor 2 is formed. Then, an ITO is formed on the organic optical conductor layer 2 by a sputtering method. A surface metal electrode 3 is formed, and a light receiving part is obtained.

Description

[Detailed description of the invention] (Industrial application field) The present invention is a facsimile machine and an image scanner.

H is applied to an image sensor used in a document reading device in a digital copying machine or the like.

(Prior art) Conventional image sensors include MOS, CCD
Although IC technology is used, the chip size thereof is generally as small as 20 to 30 m, so an optical system is required to reduce and project the reflected light image of the read image. Ninth, the optical path length from the original to the IC sensor as an image sensor is long, it is difficult to miniaturize the device, and image formation adjustment is complicated.

In order to solve these drawbacks, the size of the image sensor is made the same as the width of the document to be read, and the image is read by bringing the image sensor into almost close contact with the surface of the document to be read. So-called contact image sensors have been developed and are on the market. In such a close contact type senna, 5e-As-
An inorganic photoconductive thin film made of Te, Ca8-Cd5@, a-81:H by vacuum evaporation method, plasma CVD method, etc. is used for the photoelectric conversion section, and multiple chips such as CCD or the like are used. There is.

(Problems to be Solved by the Invention) However, in such conventional contact-type image sensors, since a high vacuum atmosphere is required in any method for forming an inorganic photoconductive thin film, the formation process is difficult. Due to the high film cost, it is difficult and rare to create a uniform long one-dimensional image sensor or a uniform wide-area two-dimensional image sensor. If multiple chips such as CCD or CCD were used, the lid would be expensive, which hindered its popularization for consumer use.

The problem to be solved by the present invention is to solve the problems of the prior art and to provide a contact type image sensor at a low cost.

(Means for Solving the Problems) In order to solve the above problems, the present invention includes an organic photoconductor layer, a front metal electrode and a back metal electrode laminated above and below a core layer, An image sensor is provided, wherein the organic photoconductor layer contains a charge generating agent and a charge transporting agent.

The organic photoconductor layer of the image sensor of the present invention is:

Even if it is a nine-functional separated type in which a charge generation layer containing a charge generation agent and a charge transport layer containing a charge transport agent are laminated, it is a single layer type containing a charge generation agent and a charge transport agent in one layer. It's okay.

As the charge generating agent, various pigments can be used.

Examples include azo pigments, quinone pigments, azulenium pigments, sulfuniarium pigments, pyrylium pigments, cyanine pigments, perylene pigments, indigo pigments, bisbenzimidazole pigments, phthalocyanine pigments, quinaxtone pigments, and quinoline pigments. Examples include pigments.

An example of an azo pigment is a general formula (wherein 2 is No CN, Ct, Br, H, CH5,
Represents OCH3°0C2H5,0H1-N(C2H5)2. ); represents an alkyl group of the general formula, R9 represents a phenyl group, ff1i, substituted phenyl group, X and Y each independently IC No. 2;
CN, H, CH,, OCH3, QC2H5,01(,
CL, Br, -N(c2)L5)2. ) Disazo pigments such as compounds represented by:

Examples of quinone pigments include a/toanthrone, hylanthrone, dibenzpyrenequinone, pyrenequinone,
3.4.9.10-Dibenzpyrenequinone.

Examples include brominated anthantrone, brominated dibenzpyrenequinone, brominated pyranthrone, anthraquinone thiazole, and furapanthrone.

As the biryllium pigment, for example, the general formula R-NH-
represents C-CH-, and 17 and R8 are lower (in the formula, R
", Rb, Rc, Rd and hin" R each independently represents a hydrogen atom, an aliphatic group having 1 to 15 carbon atoms, or an aromatic group, and furthermore, a pair of R& and Tad, and a pair of Hd and Re. represents the atomic group necessary to form the closed nine-aryl term that cooperates to form the hirylium nucleus. X is sulfur,
represents oxygen or selenium, and 2 represents an anionic functional group. ) and the like.

Five examples of cyanine pigments are: -The formula is a hydrogen atom;
Represents a methyl group or an ethyl group. ) and the like.

An example of a perylene pigment is - formula (wherein R represents a methyl group, ethyl group or allyl group, X represents CL,
Br, I, Y and 2 each independently represent oxygen,
represents sulfur or selenium, A represents =CH-CH=C-CH=CH-CH=, and Q
(In the formula, Q represents an alkyl group, an allyl group, an alkylaryl group, an alkoxyl group, a heterocyclic substituent, or a halogen atom.) ) and the like.

Indigo-based pigments include, for example, the formula - or - formula υ or - formula (wherein R represents an alkyl group, an aryl group, an amine group, or a halogen atom, and X and Y are each independently KNH,
Represents O, S, 8 or T. ) and the like.

An example of a bispenciimidazole pigment (in the formula,
R9 and R10 each independently represent an optionally substituted alkyl group, an optionally substituted aryl group, a halogen atom, a nitro group, or an amine group; good. ), and compounds having a heterocycle obtained by the reaction of 1.4.5.8-tetracarboxylic acid 7-tali/ with a heterocyclic diamine.

For example, the phthalocyanine pigment has the general formula (where x, , x2. x and X4 each independently represent
・Represents a logon atom, nitro group, amine group, alkyl group or aryl group, and n, m, L and k are each independently 0
Represents an integer of ~4, and 1M is a hydrogen atom, sodium, potassium, copper, iron, beryllium, magnesium, calcium, zinc, cadmium, barium, mercury, aluminum, indium, lanthanum, neodymium, samarium, europium, cadmium, dysprosium, holmium,
Erbium, thulium, ytterbium, ruthenium,
Represents titanium, tin, hafnium, lead, thorium, vanadium, antimony, chromium, molybdenum, uranium, manganese, iron, cobalt, nickel, rhodium, palladium, onumium, platinum and oxides thereof, and X is 0 to
Represents an integer of 2. ) and the like.

Examples of quinacridone pigments include compounds represented by the formula - or the above-mentioned compounds substituted with a methyl group or a chlorine atom.

As a quinoline pigment, for example, - formula (wherein, X represents I or Br, Q represents a quinoline ring, and n is 0
Represents an integer from ~3. ) and the like.

Examples of charge transport agents include hydrazone compounds such as 4-dimethylamino-pe/zylidene-isonicotinic acid hydrazide and anthracene-9-aldehyde-phenylacetic acid-hydracine; )-5-(p-methoxyphenyl)-pyrazoline such as pyrazoline! Compounds; Oxadiazole compounds such as 2,5-bis-(p-amino-phenyl-(1))-1,3,4-oxadiazole; 2-(
In addition to oxazole compounds such as 4'-dimethyl-aminophenyl)-benzoxazole, triphenylamine compounds, triphenylmethane compounds, and polyvinylcarno! Examples include polymer semiconductors such as sol and polysilane compounds, and polysilane compounds are particularly preferred.

The polysilane compound has the formula - (where R, R, R, R, R and R each represent an alkyl group, an aryl group, a substituted alkyl group, a substituted aryl group, and an alkoxyl group; (p is a number representing the proportion of heptad units in the compound).

A specific example of the polysilane compound represented by the above formula is poly(methylphenylsilane).

Poly(methylphenylsilylene-codimethylsilane)
, /su(cyclohexylmethylsilane), poly(tert-butylmethylsilane), poly(phenylethylsilane), poly(n-propylmethylsilane), poly(p
-tolylmethylsilane).

Poly(cyclotrimethylenesilane), Isu(cyclotetramethylenesilane), poly(cyclopentamethylenesilane), poly(di-t-butyl-codimethylsilane),
Examples include poly(diphenyl-cophenylmethylsilane), poly(cyanoethylmethylsilane), poly(2-acetoxyethylmethylsilane), poly(2-caldemethoxyethylmethylsilane), poly(phenylmethylsilane), and the like.

Polysilane compounds can be produced, for example, by reacting dino-lognosilane, dihalo-nodisilane, or dihalogeno-trisilane with a metal or alloy such as sodium, lithium, or magnesium, followed by dehalogenation polycondensation.

The molecular weight of the polysilane compound is 300,000 to 1.0
A range of 00,000 is preferred.

An optional component for forming the organic photoconductor layer includes a resin binder. As a resin binder, for example,
Polyester, polyvinyl butyral, polyvinyl carbazole, polycar? Examples include nate resin, epoxy resin, polyhydroxy ether resin, and the like.

A single dye sensitizer or a chemical sensitizer can be used as an optional component for forming the functionally separated charge generation layer.

Examples of dye sensitizers include malachite green, crystal violet, methyl violet, night blue, Victoria blue, rhodamine B, fog blue, methylene blue, fuchsin, rosepe/gal, polymethine dyes, thioxanthin pigments, and the like.

Examples of chemical sensitizers include 1. For example, p-benzoquinone; 2.
5-') Chlorobenzoquinone, benzophenone tetracarboxylic acid dianhydride, 2,6-dichlorobenzoquinone, chloranil, naphthoquinone-(1,4),
2.3-dichloronaphthoquinone-(1,4), anthraquinone, 2-methylanthraquinone, 1,4-dimethyl-anthraquinone, 1-chloroanthraquinone, anthraquinone-2-carganic acid, 1,5-dichloroanthraquinone , 1-3t OA/ -4-nitroanthraquinone, phenanthrene-quinone, acenaphthenequinone, pyrantrenequinone, chrysene-quinone, thio-, naphthene-quinone, anthraquinone-1,8-disulfonic acid and anthraquinone-2-aldehyde. Quinones such as driftthaloylbenzene, 4-nitropendialdehyde, 2,6-cyclobenzaltehyde.

2-Ethoxy-1-naphthaltehyde, anthracene-
Altehydes such as 9-flutehyde, pyrene-3-aldehyde oxindole-3-altehyde, pyridine-2,6-dialdehyde, and biphenyl-4-aldehyde;
C) Organic 7-phosphonic acids such as 4-chloro-3-nitrobenzene-phosphonic acids: nitrophenols such as 4-nitrophenol; picric acid; e.g. acetic anhydride, anhydrous ...of phosphoric acid, maleic anhydride, 7-taric anhydride, tetrachlorophthalic anhydride, pyrene-3,4,9,10-tetracarboxylic acid and chrysene-2,3,8,9-tetracarboxylic anhydride. Anhydrous acids such as metals of IB, groups N to II of the periodic table, and metalloids such as aluminum chloride, zinc chloride, ferric chloride, tin tetrachloride.

(stannic chloride), arsenic trichloride, stannous chloride, antimony pentachloride, magnesium chloride, magnesium bromide, calcium bromide, calcium iodide, strontium bromide, chromium bromide, manganous chloride, stannous chloride Monocobalt, cobaltic chloride, cupric bromide, cerium chloride, thorium chloride, arsenic Misawa; boron compounds such as boron trifluoride and boron trichloride; such as acetophuninone, benzophenone, -7 Cetylnaphthalene, benzyl, penzoycin, 5-benzoylacenaphthene, 9
-7 cetyl-anthracene, 9-benzoyl-anthracene, 4-(4-dimethylamino-cinnamoyl)-1-
Acetylbenzene, acetoacetic acid-anilide, indanedione-(1,3), (1-3-diketo-
hydroquinone).

Acenaphthenequinone-dichloride, anisyl, 2.2
- Ketones such as pyridyl and furyl.

The thickness of the organic photoconductor layer may be arbitrary, but in the case of a single layer type, the thickness is preferably in the range of 0.1 to 10 μm. In the case of functionally separated type, the thickness of the charge generation layer is 0501 to 0.5
The thickness of the charge transport layer is preferably in the range of μm.
A range of 10 μm is preferred.

The method for manufacturing the image sensor of the present invention includes glass,
The above-mentioned organic photoconductor layer is formed on a back metal electrode in which a thin metal film of aluminum, chromium, nickel, etc. is formed on a substrate of ceramic% polyethylene or the like by a method such as sputtering or vapor deposition.

Further, there is a method of forming a surface metal electrode made of a transparent thin film of a metal oxide such as fi, ITo, indium rR, or tin oxide on the organic photoconductor layer by sputtering, vapor deposition, or the like.

(Function) In Fig. 1, the organic photoconductor layer (2), the transparent front metal electrode (3), and the back electrode (4) are each connected in a shut-key manner, and a voltage is applied between the two electrodes. Figure 2 is a plan view of the photoelectric conversion section of the image sensor of the present invention viewed from the surface electrode (3) side, and shows a plurality of bits arranged in a row. Of these, only 4 bits (4 in kl~) are shown.

In the contact image sensor configured in this way, light from the light source reflected from the reading image surface of the original passes through the transparent metal electrode (3) and is absorbed by the charge generating agent in the organic photoconductor layer (2). and generate charge carriers. Therefore, the front metal electrode (3) and the back metal electrode (4) that constitute each bit
If these are connected and a low voltage of about 5V is applied, nine currents will flow through each bit in accordance with the information of the corresponding pixel bit of the original image, and these can be extracted as image signals.

To reduce dark current, a blocking contact is made between the electrode and the organic photoconductor layer.

The photocurrent per pin 2) is small, and the storage type is preferable as a signal detection method. Note 1. [As the driving method, a direct drive type or a matrix drive type is preferable.

(Example) Example 1 A nonaturn aluminum back metal electrode (4) shown in FIG. 2 was deposited on a glass substrate (1) by vapor deposition. )
The film was formed to a thickness of 300 nm. Next, polyvinyl butyral resin (“Eslec BBH-3J” manufactured by Tanezu Kagaku Co., Ltd.)
1 part by weight and 2 parts by weight of the benzidine-based disazo pigment represented by the formula are dispersed in a mixed solvent consisting of 780 parts by weight of dioxa and 20 parts by weight of acetone, and this dispersion is used to form the electrode (4).
Make sure the dry film thickness is 0.1 μm on top! No. 11 cloth was dried to form a charge-generating N (5).

Furthermore, poly(methylphenylsilane) (molecular weight 190.
000), 60 parts by weight of toluene, and 30 parts by weight of Na2H2F2 were added to the charge generating layer (5
) and dried to form a charge transport layer (6), thereby forming an organic photoconductor layer (2) with a thickness of 1 μm.

Next, on the organic photoconductor layer (2), ITO with a thickness of 150 nm was formed by sputtering.

Surface gold 141! A pole (3) was formed to obtain a light receiving section.

A contact image sensor was manufactured by incorporating the light receiving section having the layered structure thus obtained into an accumulation type readout circuit, and its performance was evaluated. As a result, a green GaPIJD was used as a light source, and a light of 100 lux was emitted.

When exposed to light, a photoresponse speed of 100 μs, a photocurrent of 1 nA/bit, and an Ijll dark current ratio of 105 were obtained.
It could be read in 0 seconds (5 milliseconds/line).

Example 2 In the same manner as in Example 1, a back metal electrode made of aluminum (
4) was obtained. Next, 1 part by weight of α-type titanyl 7-thalocyanine was dispersed in a mixed solvent consisting of 40 parts by weight of Tadelev chloride and 60 parts by weight of 1.1.2-trictetraloethane, and 1 part by weight of this dispersion and poly(methylphenyl- 1 part by weight of a solution consisting of 10 parts by weight of 1-cosomethylsilane (molecular weight 900.000), 60 parts by weight of toluene, and 40 parts by weight of tetrahydro-7rane were mixed well, and a dry coating thickness was formed on the electrode (4). It was coated to a thickness of 1 μm and dried to form an organic photoconductor layer (2).

Furthermore, a 150 nm thick KITO film was formed on the organic photoconductor layer (2) by a sputtering method, and a surface metal electrode (3) was formed to obtain a light receiving section.

A contact type image sensor was manufactured by incorporating the light receiving section having the layered structure thus obtained into an accumulation type readout circuit using an LED with an emission wavelength of 570 nm as a light source, and its performance was evaluated. As a result, when irradiated with 100 lux light, the photoresponse speed was 100 μs and the photocurrent was 1 nA/pic).
,F! A dark current ratio IO was obtained, and an A4 size original was heated for 10 seconds (5
It could be read in milliseconds/line).

(Effects of the Invention) According to the present invention, since the photoelectric conversion section is constructed using an organic photoconductor, an inexpensive and large-area image sensor can be manufactured. That is, the organic photoconductor is
Unlike inorganic photoconductors, it can be formed into a film by coating, and because it is highly flexible, the substrate can be left on freely, making it possible to obtain an inexpensive image sensor. And by Ik cloth.

Since a long or wide-area uniform organic photoconductor layer can be easily formed, a long-dimensional or wide-area two-dimensional contact image sensor can be easily produced.

Furthermore, according to the present invention, it can be easily developed into a color sensor by adding one dye.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a contact type image sensor according to the present invention, FIG. 2 is a plan view thereof, and FIGS. 3 to 5 are examples of the structure of an organic photoconductor layer. DESCRIPTION OF SYMBOLS 1... Substrate, 2... Organic photoconductor layer, 3... Surface metal electrode, 4... Back metal electrode, 5, 9... Charge generation layer, 7... Charge generation agent, 6.10... Charge transport layer, 8... Charge transport agent. Figure Figure Figure Figure 1 Procedures Amendment (self-motivated) March 1999 Complaint Date Director General of the Patent Office Yoshiki 1) Moon Takeshi 1, Indication of the Case 1988 Patent Application No. 308840-1 Name of the invention: Image sensor 3, relationship with the person making the amendment case Patent applicant: 3-35-58 Sakashita, Itabashi-ku, Tokyo 174 (2)
88) Dainippon Ink & Chemicals Co., Ltd. Representative Kawa
Kuni Mura Shigeru 4, Agent Address: 103 3-7-20 Nihonbashi, Chuo-ku, Tokyo 1 True Subject 6, Contents of Amendment (1) r Ca5-CdSe, J Worr in the second line of page 3 of the specification Cd5-CdSe, corrected to J. (2) "Azulenium pigment...cyanine pigment" in lines 11 to 13 of page 4 of the specification is corrected to "azurenium dye, sufuuniarium dye, pyrylium dye, cyanine dye." (3) "In lines 2 to 4 of page 6 of the specification"
X and Y represent... ” to “X is NO2, CN, H, CH,, OCH3, QC
2H5,Of(. CL + Bre −N(C2H5) represents 2,
Y represents OH. ”. (4) "Pyrylium nucleus" in the second line of page 7 of the specification is corrected to "pyrillium nucleus." (5) "Cyanine pigment" on page 7, line 7 of the specification is corrected to "cyanine dye." (6) "Heterocyclic substituent or halodane atom" in Mei M, page 8, lines 6 to 7 is corrected to "heterocycle having a substituent." (7) The structural formula on the bottom line of page 10 of the specification is corrected to ``. " is corrected to "poly(methylphenyl-codimethylsilane)". (9) r 300,000 to 1,000,000J in lines 17 to 18 on page 14 of the specification cylinder to r 50
,000 to 2,000,000 J. 01 "Benzidine series" in the specification @ page 20, line 10 is corrected to "stilbene series". aυ r190,0 on page 20, line 16 of the specification
Correct OOJ to r 70,000 J. "Poly(methylphenyl-1-codimeylsilane)
...40 parts by weight" is corrected to "10 parts by weight of poly(methylphenyl-codimethylsilane) (molecular weight 500,000), 60 parts by weight of toluene, and 30 parts by weight J of tetrahydrofuran.

Claims (1)

[Scope of Claims] 1. An organic photoconductor layer, a front metal electrode and a back metal electrode laminated above and below the layer, the organic photoconductor layer containing a charge generating agent and a charge transporting agent. An image sensor characterized by containing. 2. The image sensor according to claim 1, wherein the charge transport agent is a polysilane compound. 3. Polysilane compounds have a general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, R^1, R^2, R^3, R^4, R^5 and R^6 are each independently alkyl The image according to claim 2, which is a compound represented by the following formula: a group, an aryl group, a substituted alkyl group, a substituted aryl group, or an alkoxyl group, and m, n, and p are numbers representing the proportion of monomer units in the compound. sensor.