JPH0486155A - Image reader and communication terminal using this reader - Google Patents

Abstract

PURPOSE:To obtain a uniform illuminance on a light receiving element to reduce the thickness of a read sensor by forming a light emitting element and the light receiving element of a linear light source unified contact read sensor with linear EL light emission sources and arranging them on substrates. CONSTITUTION:A light source part 2 consists of a back electrode 6, a first insulating layer 7, an EL emission source 8, a second insulating layer 9, and a transparent electrode 10 formed on a substrate 5, and they are covered with a protective layer 11. A light reception part 1 consists of a photoelectric conversion layer 12, an electrode 13, and a protective layer 11. The substrate 5 of the light reception part and that of the light source part are sealed with a humidity resisting resin (sealing material) so that they are not exposed to moisture in the air. In this case, they are so adhered that the maximum luminance part of the EL emission source is just under an incidence window of the light reception part 1. A light shielding film 15 is provided under the photoelectric conversion part of the light reception part 1. An original 4 is irradiated with illuminating light 3 from the light source part 2, and the reflected light reflecting the contrast of the original is detected by the light reception part 1. Since the light source part 2 is placed on the rear face of the light reception part 1, a special optical system is unnecessary to simplify the structure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an image reading device, and particularly to an image reading device that uses a contact type reading sensor and has a miniaturized entire device, and a communication terminal using the device. Regarding.

[Prior Art] In conventional image reading devices, the contact type reading sensor includes a cold cathode tube and an LED array. For example, as described in Japanese Unexamined Patent Publication No. 58-143665, a cold cathode tube with little variation in brightness is used as a light source, and the tube diameter is 5 to 12 m. Also, JP-A-61
As described in Japanese Patent No. 39771, there is an example in which a glass substrate on which a light receiving element is formed is assembled together with an LED array formed on a GaAS substrate. L.E.
Since the D array has a thinner plate than cold cathode tubes, the sensor itself can be made thinner. Furthermore, JP-A-59-8196
As described in Japanese Patent No. 7, when an LED array as a light emitting source and a light receiving element are formed on the same substrate, the sensor itself can be further miniaturized.

In addition, as described in Japanese Patent Application Laid-Open No. 1-162366,
The sensor itself has been miniaturized by integrally forming a surface light source made of an EL light emitting element, an optical sensor array, and a drive circuit section on a substrate.

However, when a cold cathode tube is used as a light source, the diameter of the tube is φ5 to 12 m, so there is a drawback that the thickness of the entire sensor cannot be reduced even though the substrate is thin. Further, as described in Japanese Patent Application Laid-Open No. 61-39771, a glass substrate on which a light receiving element is formed and a normal G a A
In an example where an LED array formed on an S substrate is assembled and used, the brightness of each LED array varies, so this must be electrically trimmed. Moreover, there is a drawback that even with trimming, the brightness cannot be made completely constant. Also, JP-A-1-16236
As described in Publication No. 6, when an EL light emitter and a photosensor array are formed on the same substrate, noise is generated from the EL light emitter driven at a high voltage of about 200 kHz and a frequency of 1 kHz or more.

This has a negative effect on optical sensors that detect minute currents.

High sensitivity reading was not possible. In addition, during heat treatment at 500°C or higher, which is necessary to increase the brightness of EL emitters, hydrogen from a-8i:H used in optical sensors is released, and some of the amorphous structure crystallizes, resulting in a decrease in photoelectric conversion efficiency. Therefore, there was a drawback that a sensor with sufficient characteristics could not be manufactured using the same process. Furthermore, when an EL light emitter is formed immediately next to the optical sensor array, a portion of the EL light emitted as scattered light is directly incident on the optical sensor, which has the disadvantage that the pale colors of the document are blown out and cannot be read.

In addition, using a quartz substrate as a substrate increases the cost and the surface area of the substrate that can be manufactured is small.
It was not possible to create a close-contact reading sensor for 4 drawing sizes.

Furthermore, when using an LED array as a light source, the sensor can be made thinner than when using a cold cathode tube, but since it is a point light source and the brightness of each light source varies, a correction circuit and trimming are essential. . Moreover, since it is a point light source and the number of reading elements of the sensor is greater than the number of light sources, it is inevitable that variations in illuminance will occur from element to element.

On the other hand, the LED array is formed on a GaAs substrate,
The process is complicated and therefore expensive.

Furthermore, when forming an LED array and a light receiving element as a light emitting source on a glass substrate, first GaAs is used instead of directly.
M B E (Molecular Beam Ep
GaAs, GaAlA is formed on top of it by liquid phase epitaxy.
An LED can be formed by stacking s and processing pixels by photo-etching, and cannot be manufactured at low cost.

[Problem to be solved by the invention]

In the case of a close-contact reading sensor installed in a conventional reading device, if a cold cathode tube is used as a light emitting source, the thickness of the sensor cannot be made thin, and if an LED array and a light receiving element are formed on a substrate, the brightness of the LED array It is necessary to electrically trim the variations in the sensor array, and if the EL emitter is formed on the same substrate as the optical sensor array, there are drawbacks such as the inability to perform high-sensitivity reading due to noise, which makes it impossible to miniaturize the device. Ta.

The purpose of the present invention is to be able to read multiple gradations, and to
In order to make the device thinner, the reading sensor is made thinner to reduce its manufacturing cost, and at the same time, it provides an image reading device having a reading sensor capable of high-speed reading so as to be compatible with I5DN, and a communication terminal using the device. It's about doing.

[Means for solving the invention]

In order to achieve the above-mentioned object, an image reading device according to the present invention is an image reading device including a light receiving element and a light emitting element disposed on a substrate, and a reading sensor that closely scans a document and reads its information. , formed by a linear light-receiving element provided on an optically transparent substrate facing the original, and a light-emitting element provided almost parallel to the light-receiving element via the substrate and having a linear EL light source. The structure is equipped with a close-contact reading sensor integrated with a line light source.

The line light source integrated close-contact reading sensor consists of a light receiving element disposed on a first substrate and a light emitting element disposed on a second substrate. 1
The light receiving element is attached to the second substrate and sandwiched between the light receiving element and the second substrate, and is disposed at a position where the emitted illumination light passes near the light receiving element.

Further, the line light source integrated contact reading sensor has a structure in which the periphery of the light emitting element is sealed with a water-resistant resin.

Furthermore, the line light source integrated contact reading sensor has a structure in which the electrode on the light receiving element side of the light emitting element is formed of a transparent electrode.

In the line light source integrated contact reading sensor, the EL light source of the light emitting element is placed between a pair of transparent electrodes and a back electrode.
The structure is such that they are sandwiched between an insulating layer and a second insulating layer.

In addition, in an image reading device that has a light receiving element and a light emitting element disposed on a substrate, and is equipped with a reading sensor that closely scans the document and reads its information, an optically transparent first substrate is placed facing the document. a linear light-receiving element provided at a linear light-receiving element; and a line provided on an end surface having an inclined angle of a second substrate facing the light-receiving element, and the inclination angle of which is adjusted to a position where the illumination light generated by the emission passes near the light-receiving element. The structure may include a light emitting element having an EL light source, and a close reading sensor integrated with a line light source.

Further, the line light source integrated contact reading sensor may have a structure in which an EL light source of one light emitting element is sandwiched between a pair of opaque electrodes with a first N edge layer and a second insulating layer interposed therebetween.

The line light source integrated contact reading sensor has a structure in which a light emitting element is formed by an EL light emitting source, an electrode, and an insulating layer that are continuous in the length direction of a light receiving element.

In addition, the close-contact reading sensor with integrated line light source
A configuration in which the L light emitting source is branched into a plurality of branches may also be used.

Furthermore, the line light source integrated contact reading sensor has an EL light source of a light emitting element sandwiched between a back electrode and a transparent electroluminescent electrode with an insulating layer interposed therebetween, and a luminescent powder dispersed in an organic binder. The light emitting element may be formed of a dispersed EL light emitting element and may have a structure in which the periphery of the light emitting element is covered with a package film.

The line light source integrated contact reading sensor may have a configuration in which the EL light source of the light emitting element is formed of a laminated film of an amine-based organic compound and an organometallic chelate complex, and is driven by a DC circuit of 10 ov or less.

Further, the line light source integrated contact reading sensor is configured such that the scanning frequency of the light receiving element and the driving frequency of the EL light source are synchronized.

Further, a light receiving element and a light emitting element are arranged on the substrate.

In an image reading device equipped with a reading sensor that closely scans a document and reads its information, a linear light receiving element is installed on an optically transparent substrate facing the document, and a linear light receiving element is installed on a convex part on the back side of the substrate. The structure may include a linear light source integrated close-contact reading device formed by a light emitting element having a linear EL light source formed at a position where the illumination light emitted from the light emitted passes near the light receiving element.

In the close-contact reading sensor with integrated line light source, the EL light source of the light emitting element is formed of a white EL light emitter, and red, green, and yellow color filters are provided on the surface of the protective film of the light receiving element facing the original. A configuration may also be used.

In addition, the close-contact reading sensor with integrated line light source
The L light source may be formed of a white EL light emitter, and red, green, and yellow color filters may be moved on the surface of the protective film of the light-receiving element facing the document each time the entire surface of the document is scanned.

Furthermore, the linear light source integrated close-contact reading sensor may have a structure in which the substrate of the light receiving element is formed of a glass substrate with a heat resistance temperature of 600° C. or less, and a driving circuit for scanning the light receiving element is provided.

In the close-contact reading sensor with integrated linear light source, the substrate of the light-receiving element is formed of a glass substrate with a heat resistance temperature of 600 degrees Celsius or less, and a linear sensor made of one of a photodiode, a photoconductor, or a phototransistor is mounted on the glass substrate. The structure may include a light receiving element, a scanning circuit including at least one of a shift register, a level shifter, or a multiplexer, and a thin film circuit including an impedance conversion circuit or an analog voltage conversion circuit.

Furthermore, the line light source integrated close-contact reading sensor has a thickness of five layers.

Furthermore, the line light source integrated contact reading sensor may have a structure in which a conductive layer for noise absorption is provided between one light emitting element and one light receiving element.

In the close-contact reading sensor with integrated line light source, a light receiving element and a light emitting element are arranged on the same substrate, and a lens is provided between each element and the document to prevent illumination light from directly entering the light receiving element. It is also possible to have a configuration in which

In addition, the close-contact reading sensor with integrated line light source
The light emitting material of the L light source is ZnS:Mn or SrS:Pr.
, Ce may be used. In order to make a white light emitting source, Zns:Pr, Sr is used as a light emitting material.
S: Pr, SrS: C6, Eu and SrS: Ce and Sr
S: Laminated material with Eu, S rS: Ce and CaS: E
A laminated material of SrS:Ce and 2nS:Mn may also be used.

In addition, the close-contact reading sensor with integrated line light source
The L light source is formed of a thin film EL, and there is a threshold voltage of 1 between the output when reading black and the output when reading red or vermilion, and the output when reading red or vermilion and the output when reading white. A threshold voltage 2 is set between the output when 3 as white output
A configuration in which the values are converted into values may be used.

Furthermore, the linear light source integrated contact reading sensor may have a structure in which the light emitting material of the light emitting element is locally heat treated.

In the image reading device according to any one of claims 1 to 23, a close reading sensor integrated with a linear light source or an integrated reading sensor integrated with a parking circuit is used as the image reading section, and a portable card is used as the information recording section. The configuration includes a type optical disk memory.

Further, the image reading device according to any one of claims 1 to 24, or a communication terminal comprising this device, a communication interface, and a signal processing section, includes a portable card-type optical disk memory as a transmission/reception information recording section. The close-contact reading sensor integrated with a line light source is configured to use an integrated reading sensor with an integrated drive circuit as an image reading section.

Further, the communication terminal is configured to use the image reading device according to any one of claims 1 to 24.

[Effect]

According to the image reading device of the present invention, by forming a -dimensional (linear) continuous light receiving element on the substrate and a linear continuous EL light emitting source on the opposite side of the document, the EL light emitting source can be used as a sensor. The document surface is irradiated from the back side, and the light receiving element receives the contrast of the reflected light from the document. The light source section has a structure in which an EL light source is sandwiched between an insulating layer and an electrode on the upper and lower sides, and the entire surface where the EL light source and the electrode overlap is illuminated. Therefore, by forming an electrode, an insulating layer, and an EL light emitting source that are continuous in the direction of the light receiving element, that is, in the main scanning direction when reading an original, a -dimensional continuous light source can be obtained. EL
The brightness of the light emitter is determined by the film thickness of each layer, driving voltage, and frequency, so a linear continuous light source with uniform brightness can be easily realized simply by forming a film with a uniform thickness. By irradiating this EL light from the top of the sensor substrate or the back side of the substrate, uniform illuminance on the document surface can be obtained over the entire surface.

If there are variations in brightness, such as with an LED light source, variations in sensor output will occur even when reading originals with the same density. In the case of binary reading in which black and white are discriminated using a threshold value, this luminance variation is allowed, but multi-gradation reading is not possible. On the other hand, if an EL light source is used to obtain uniform illuminance on the document surface in the main scanning direction, the reference illuminance is constant, so a sensor output corresponding to the density of each document can be obtained, allowing multi-gradation reading. becomes possible.

Furthermore, since the light source brightness is constant in the main scanning direction,
There is no need to maintain a distance between the light-receiving element and the light-emitting source, and the light-emitting source can be installed on the substrate of the light-receiving element or on the back surface of the substrate, so the sensor itself can be made as thin as the thickness of the substrate.

When forming an EL light emitting source on the back surface of the substrate of the light receiving element, first form the EL light emitting source on a different substrate from the light receiving element, and then
The open substrates are pasted together so that the light emitting source is sandwiched between the substrates, creating a structure in which illumination light passes near the light receiving element. In this structure, by sealing the bonded portion with a moisture-resistant resin, the EL element, which easily deteriorates due to atmospheric humidity, is prevented from coming into contact with the air.

Further, as a method of forming the light receiving element and the light emitting section on the same substrate, an edge-emitting type EL light source may be formed on the end surface of the substrate on which the light receiving element is formed.

When the light receiving element is made of amorphous silicon (hereinafter abbreviated as a-Si), its power generation efficiency is at wavelengths of 570 to 6.
It has a peak in a relatively wide wavelength range of 30 nm. However, with LED light sources, various wavelengths can be obtained, but each has a very sharp peak with a half-width of 10 nm, and a-
The high power generation efficiency of 5i over a wide wavelength range cannot be utilized. On the other hand, in the EL light source, Zn is used as the light emitting layer.
When S:Mn is used, it has a slightly broad peak at 570 to 600 nm, so the characteristics of a-Si can be fully utilized.

A linear light-receiving element and a driving circuit for scanning it are formed using thin film circuits on a glass substrate with a heat resistance temperature of 600 degrees Celsius or less.
By using one of a photodiode, a photoconductor, or a phototransistor as a light-receiving element, and forming a thin film circuit with a combination of at least one of a shift register, a level shifter, a multiplexer, etc. as a scanning circuit, the pixel density can be increased. When a high-definition read signal of 400 dpi is weak, an impedance conversion circuit or an analog voltage conversion circuit is mounted as a first-stage amplifier on the substrate as a thin film circuit, which results in an inexpensive and large-area substrate.

In this way, by combining a sensor substrate in which a light receiving part and a driving circuit are integrated on a glass substrate with a photodiode or a photoconductor, and a polycrystalline S1 or amorphous Si thin film transistor (TPT), and a light emitting part substrate. All the components of the line light source integrated contact reading sensor are formed of thin films.

〔Example〕

Embodiment 1 of the present invention will be described with reference to FIG.

Embodiment 1: As shown in FIG. 1, a reading sensor includes a light receiving section (light receiving element) 1 and a light source section (light emitting element) 2. The film structure of the light source section 2 includes a back electrode 6, a first NM layer 7, an EL light source 8, a second insulating layer 9, and a transparent electrode 10 formed on the substrate 5 side, and covered with a protective layer 11. On the other hand, the light receiving section 1 includes a photoelectric conversion IF 12, an electrode 13, and a protective layer 11 for them. The substrate 5 of the light receiving section and the substrate 5 of the light source section are coated with a moisture-resistant resin (sealing material) 14 to prevent the light source section 2 from coming into contact with moisture in the atmosphere.
Seal with. At this time, the EL light emitting source is bonded so that the highest brightness part is directly below the entrance window of the light receiving section 1. Furthermore, it is necessary to provide a light shielding film 15 below the photoelectric conversion section of the light receiving section l in order to prevent direct incidence of light from the EL light source. Illumination light 3 emitted from a light source section 2 illuminates a document 4, and a light receiving section 1 detects reflected light reflecting the contrast of the document. Light source part 2
is located on the back surface of the light receiving section 1, so a special optical system is not required and the structure can be simplified. Furthermore, the overall film thickness of each of the light receiving section 1 and the light source section 2 is 2 μm or less, so even if the substrate 5 with a board thickness of 1 mm is used and the sensor parking IC is mounted, the overall thickness of the reading sensor is 4 mm or less. It can be made thinner.

On the other hand, when a conventional cold cathode tube is used, at least about 20III11 is required to assemble the reading element and the light source even when the thinnest cold cathode tube is used.

FIG. 2 shows a plan view of the close-contact reading sensor integrated with a line light source of the present invention. The EL light source has an electrode, an insulating layer, and an EL light source formed in a linear shape so as to form a continuous one-dimensional light source section parallel to the light receiving section. The shape of the light source is A4 with a width of about 1m.
Since the length is the same as that of B4 size paper, its molding is very easy compared to the light receiving section. Therefore, by using techniques such as mask evaporation, the light source section can be processed without photo-etching.

By configuring the reading sensor as shown in Figure 1, it can be used as a sensor that scans in complete contact with the document, so the thickness of the sensor, including the light source section, is approximately 2 m, which is the thickness of two substrates. An image reading device or a communication terminal using the same can be made thinner.

FIG. 3 is an example of a paperless facsimile in which the entire device is made thinner than 5 am using the reading sensor of this embodiment. In order to eliminate the photographic paper roll which is the reason why facsimiles cannot be made thin, a liquid crystal display 16 and an ultra-thin optical disk medium 17 are used as recording media, and a close-contact reading sensor 18 with integrated line light source is used instead of photographic paper and a printer. As a result, the thickness of a communication terminal such as a facsimile can be reduced to 51 mm or less.

FIG. 4 shows its block diagram. In this example, the reading sensor is thin at about 31111+, and since photographic paper is not used, the thickness of the sheet-like optical disc is 15 mm.
The thickness of the entire device can be reduced to about 3 to 5 (1), making it an optimal system not only for devices but also for mobile communication in cars and the like. Of course, even if photographic paper and a thermal head are used as the recording section, the facsimile can be made as thin as the thickness of a roll of photographic paper.

A second embodiment of the present invention will be described with reference to FIG.

Embodiment 2; FIG. 5 is a cross-sectional view of an example of an image reading device of the present invention;
FIG. 6 shows a block diagram. By bringing the original 4 into close contact with the linear light source integrated contact reading sensor 18 using the platen roller 24, the contents of the g original are read. In this embodiment, the read information can be recorded on the card-type recording medium 17. When a card-shaped optical disk is used as the medium, the information recording/reproducing device 25 records the information on the optical disk. Even when combined, the entire image reading device can be made as thin as approximately 30 m+. If it does not include a recording medium, the image reading device is substantially determined by the diameter of the platen roller and can be as thin as 10+m.

Embodiment 3; Figure 7 is an example of a case where the position of the light receiving element 1 and the position of the light source section 2 are shifted to support not only complete close reading but also image reading using a 5x optical system. . By using opaque electrodes such as metal for the upper and lower electrodes 6 and 10 of the light emitting layer, the generated illumination light 3 is generated from the end face of the EL light source. Moreover, since it emits light with an efficiency 100 times that of surface emitting light, it becomes a linear light emitting source with sufficient brightness. Light emitting element 1
Since the position of the light source section 2 is shifted from the position of the light source section 2, even if the emitted light is reflected onto the document at the end surface perpendicular to the surface of the substrate 19 on which the light receiving element is formed, it does not enter the light receiving section. Therefore, the end face of the substrate is processed to have a taper (angle of inclination) as shown in the figure, and a light source section is formed thereon. The taper angle is determined by the distance between the light receiving section and the document.

Furthermore, the distance between the light receiving section and the document is determined by the thickness of the 5x optical system provided therebetween. For example, when using a SELFOC lens, this length is about 20III11, and its taper becomes more vertical. On the other hand, when a sheet-like lens with a thinner plate thickness of 1 mm or less is used, the distance is about 1 mm, and the taper angle becomes small. Furthermore, it also depends on the distance between the light receiving section and the light source section, and is determined by taking these into consideration. In this embodiment, both the light-receiving element and the light source can be formed on a single substrate, and it can be applied to a close-contact type that is in complete contact.6Furthermore, the light-emitting source is much thinner than the surface-emitting type, and the reading part You can eliminate unnecessary information.

That is, by using an edge EL light source, the width of the light source is extremely narrow, so that only a portion of the document is irradiated, and therefore noise caused by stray light from the document other than the one being read can be reduced. Furthermore, because it is highly efficient as a light source,
Low power consumption also prevents overheating of the light receiving element. Furthermore, since the light is emitted from a location away from the light-receiving element, it can be applied to either a complete contact type in which the sensor is placed in close contact with the document for reading, or a close contact type in which a 1x optical system such as a Selfoc lens is used.

Embodiment 4; FIG. 8 shows an example of a cross-sectional view of a reading sensor of the present invention. First, a polysilicon thin film transistor (p Si TFT) is formed as a scanning circuit on a glass substrate having a heat-resistant temperature of 600° C. or less using normal pressure and low pressure CVD methods at a temperature of 450° C. or less. Thereon, an amorphous silicon (a-5i) photodiode is formed as a light receiving element by plasma CVD at 230 DEG C. Low pressure CV of p-8i film of active layer
After forming 800 layers using the D method and implanting phosphorus ions into the source and drain contacts to make them n-type, 100 layers of Sin for the gate insulating film were formed using the normal pressure CVD method, and a large amount of phosphorus was used as the gate electrode. 1 doped p-Si
000 people will deposit. After forming a film of 6,000 layers of phosphosilicate glass as an interlayer #@edge film, aluminum is formed as a source and drain electrode by a 6,000 layer sputtering method and processed into wiring.

A 1,000 chromium film is deposited thereon by sputtering to form the lower electrode of the photodiode. Then, a non-doped 1-a-5i film and a boron-doped p-a-
8i and 1 μm each were formed continuously at 230° C. for 300 people. Furthermore, 1000 people deposited chromium for the upper electrode. Here, by annealing at 200° C. and removing the chromium film by etching, a transparent electrode made of chromium silicide can be formed. Finally, a protective layer of about 1 μm thick is formed using a transparent insulating film such as SiN. FIG. 9 shows the characteristics of the p-8i TFT formed on this glass substrate. The off current is l
It is 0PA or less. The n10ff ratio is about 7 digits. Further, its mobility was 25 aJ/Vs, and the L threshold voltage was 7 V, and sufficient characteristics were obtained to form a scanning circuit for a reading sensor. Formation of p-5iTFT begins with P-5
Although an example of forming an i film has been described, an a-8i film is first formed, and later a p-8i film is partially formed by a method such as laser annealing.
It may be crystallized.

FIG. 10 is a diagram comparing the amount of charge accumulated in a photodiode at 400 dpi with that at 200 dpi. 400dp
At (7) the amount of accumulated charge is reduced to about 1/17 of 200 dpi. Therefore, in order to increase the resistance of weak signals to noise, a p-8i TFT analog voltage conversion circuit was installed immediately adjacent to the photoelectric conversion section in the reading sensor circuit shown in FIG. This conversion circuit can reduce the high impedance of the photodiode to about 1/1000, that is, amplify the current and output the input voltage from the sensor with good linearity. FIG. 12 shows changes in the output of this 400 dpi reading sensor depending on illuminance. The fact that linear output can be obtained over a wide illuminance range shows that it is possible to read multiple gradations. Here, the light receiving element may be of a photoconductor type instead of a photodiode. A photodiode is suitable when high-speed performance is required, and a photoconductor type is suitable for manufacturing at a lower cost.

Example 5: When ZnS:Mn is used as the light-emitting layer (EL light source) in a thin film EL as the light-emitting material of the reading sensor, the spectrum of the light-emitting layer is a as shown in FIG. -8i sensor's highest sensitivity 580nm to 600nm
nm, the sensor output is higher than that of green fluorescent lamps, green LEDs, etc. even with the same amount of light, and the MTF etc. are also improved as shown in Figures 14 and 15. However, on the other hand, the peak wavelength is closer to vermilion than that of a green fluorescent lamp, so when reading a vermilion color such as a seal, the sensor output is reduced to about 172 compared to black, as shown in Figure 16. . Therefore, a threshold voltage of 1 is set between the thinking power and the walking power,
Further, a threshold voltage 2 is set between the step output and the white output. If the sensor output when reading a manuscript is more than the threshold voltage 1, it is considered as thinking power, if it is between threshold voltage 1 and 2, it is considered walking power, and if it is less than threshold voltage 2, it is considered as thinking power. White output and ternary conversion are possible. More single wavelength LEDs
When using , since the walking power is only 0.65 times the thinking power, it is difficult to set the threshold voltage, and ternaryization is not possible. By using this embodiment, red and black can be distinguished by scanning the document once with a single sensor, whereas conventionally black and red were read using separate sensors or in two separate scans. can do. Therefore, the two-color facsimile can be made smaller and lower in cost.

Example 6: When integrating a TPT, a light-receiving element, and an EL light-emitting source on the same substrate, since the EL light-emitting source is sensitive to humidity, the manufacturing order is such that the TPT and light-receiving element are first formed, and then the EL light-emitting source is integrated. It is better to form In order to increase the brightness of the EL light source, it is necessary to anneal at about 500° C. after film formation.

However, if the TPT and the light receiving element are made of a-8i,
In order to prevent hydrogen from escaping, it cannot be heated above 300°C. Therefore, by locally annealing only the EL light source on the sensor substrate at about 500° C. using a laser or the like, it is possible to increase the brightness of the EL light source while maintaining the characteristics of a-5i.

Example 7: In order to obtain a light source with more uniform brightness, it is better to form a continuous light source over the entire reading length. However, the light emitting layer and insulating film of the EL light source have lX10sV/a.
A strong electric field of about a magnitude is applied, and if there is a defect in the film formed during film formation, film destruction may rapidly proceed from that location.

In this case, as shown in Figure 17, the propagation of the breakdown can be minimized by forming an EL light source with the lower electrode separated into multiple parts by photoetching and separating the regions to which a high electric field is applied into several parts. It can be held down. In order to maintain high brightness, it is desirable to reduce the number of non-emission areas 23 as much as possible, and the width of the non-emission areas 23 is preferably 5 to 10 μm.

Example 8: Since the light emitted from the EL light emitting source is diffused light, the light emitted from the light emitting source spreads not only directly above the light receiving element but also widely around the light receiving element, and even information in the surroundings can be read.

Therefore, in order to irradiate the light only directly above the light receiving element,
As shown in FIG. 18, it is preferable to form the light emitting source on a semi-cylindrical glaze. The light emitted from the light emitting source is condensed by the glaze in this part, which acts as a lens, and is irradiated only in the vicinity of the light receiving element, making it possible to eliminate unnecessary information from being read from the document.

Example 9: In order to reduce manufacturing costs, as shown in FIG.
By forming a light receiving element on the front side of a single substrate and forming a light source section on the back side, a reading sensor can be realized with a single substrate. In this case, a transparent electrode is formed on the substrate side so that light exits to the sensor side.

Example 10; A1 or Cr film with a thickness of approximately 0.2 μm was used for the back electrode 6 of the EL light source, and 5i02. T
a20zt SiN, SrTiO2, etc. are preferably used.

The material of the light emitting layer varies depending on the type of photoelectric conversion material of the light receiving section. When using an a-8i film as a photoelectric conversion material, ZnS:M has a peak wavelength near its absorption edge.
It is preferable to use an n-light emitter. Further, although these inorganic light-emitting materials can provide high brightness, they require a relatively high applied voltage of about 200V.

In order to drive at a lower voltage, a laminated film of a diamine-based organic compound and an organometallic chelate complex may be used. By using this organic EL light source, it can be driven with a DC power supply of 50V or less. Therefore, there is no need to synchronize the driving frequency of the EL light emitting source and the scanning frequency of the sensor section, which was necessary during AC driving. As a transparent electrode, IT
O (1ndium Tin Oxide) is good.

Example 11; As shown in FIG. 20, an EL light source 8 in which luminescent powder was dispersed in an organic binder was used as an EL light source, and one layer of insulating layer 7 was placed between the back side and the back electrode 6. Electrodes 6 and 10 are formed on both surfaces of the two surfaces. Furthermore, a distributed EL light source covered with a moisture absorbing film 32 and sealed with a package film 31 may be used. A low-luminance but inexpensive resin substrate can be used, making it possible to create an even lower-cost reading sensor.

Example 12: By using an EL light source, full-color reading becomes possible with a close-contact reading sensor integrated with a line light source, which has a simple structure, as shown in FIG. 21.

Three light receiving elements 1 are arranged in parallel, each with Red2
8. Green29. A Yellow30 optical (color) filter is provided. EL that emits white light on the back of light receiving element 1
A light emitting source 8 is formed. White light irradiates the document through the sensor irradiation window, and light of each wavelength reflected from the color document enters the three light receiving elements. By combining them, a full-color image can be reproduced. As the EL light source, a white EL light source having brightness in each of red, green, and yellow wavelengths is used. If there is a difference in the brightness of each wavelength, it is corrected using a filter or a reading circuit of the light receiving element. In this case, the luminescent material is SrS:Pr
, Ce, etc. are good. Furthermore, even if the light receiving element is used only for books, the color filter on the light receiving element may be changed to red, green, and then yellow every time the document passes over the light receiving element three times.

Example 13: As shown in FIG. 22, between the EL light source and the light receiving element,
It is desirable to have a conductive layer 33 for noise absorption. Since the EL light emitting source is driven at a high voltage of about 200 V and a frequency of 1 kHz or more, the generated noise has an adverse effect on the light receiving element that detects minute currents. Therefore, an EL light emitting source is placed on the opposite side of the light receiving element across an insulator to prevent noise from entering the light receiving element, and a grounded conductive layer 32 is formed to allow noise to escape. Since this conductive layer needs to allow light to pass through, a transparent conductive film such as ITO is preferable.

Example 14; In the example shown in Fig. 2, a linear light source is irradiated and the light receiving element is scanned, but conversely, the light emitting source is processed to 200-400 dpi5, and the light receiving element is scanned in a linear manner. May be processed.

Example 15: In order to form a light receiving element, a scanning circuit, and a light source part by a thin film process on a substrate having a heat and humidity resistance of 600°C or less, it is necessary to suppress the process temperature to 600°C or less. Among these, the film forming temperature of the light receiving element and the light source section is 250° C. or less, but a thin film scanning circuit that scans at high speed requires a higher temperature because a material with high mobility is essential. High-mobility polycrystalline silicon thin film transistors can be expected to have high mobility, but if thermally oxidized Si07 is used for the gate insulating film, the substrate needs to withstand heat treatment of 800 degrees or higher, and high-grade quartz substrates or other I have no choice but to use glass.

In this example, a j,-p-Si film formed at 450°C by low pressure CVD method is used as the active layer, an n''-p-8l film is used as the gate electrode, and 450°C is formed by normal pressure CVD method.
A SiO2 film formed at ℃ is used as a gate insulating film. Furthermore, C300°C annealing is performed as activation treatment. With the above process, a mobility of 25aj is produced on an inexpensive glass substrate.
A polycrystalline silicon thin film transistor with high mobility of /Vsee can be realized. A scanning circuit using this enables high-speed scanning. FIG. 11 shows an equivalent circuit of a read sensor manufactured using a water process, and the scanning circuit consists of a transistor, a level shifter, and a multiplexer. These are the best []-8iT
The immediate frequency of the shift register that can be configured with FT is 50
Can be scanned at ~200kHz.

To further increase speed, connect the shift register to the multiplexer via level jitter. In this embodiment, a four-stage multiplexer corresponds to the shift register ]-stage. While the shift register turns on the gates of the switches S1 to S4, pulses are sequentially applied from the external pulse circuit, 81 to S4 are sequentially opened, and the signals of the light receiving elements are sent to the signal line.

Furthermore, the process technology allows not only switching circuits but also first stage amplifier circuits for analog signals such as analog voltage conversion circuits to be integrated on the substrate. The linear density of the light receiving element is 200 dots/1nch (hereinafter referred to as d
If it is coarse (abbreviated as pi), the light receiving area is large and the scanning speed is slow, so the signal from the light receiving element is large. However, when the linear density becomes as high as 400 dpi, as in the G4 facsimile, the signal from the light receiving element becomes extremely small and is buried in circuit noise. In this case, in order to increase the resistance of the signal to noise, it is preferable to form an impedance conversion circuit on the substrate as a first-stage amplifier circuit for analog signals. The impedance conversion circuit is a type of source follower circuit in which two poly-5iTFl's of the same size are combined.

When a diode is used as the light-receiving element 5 and 1, its output impedance is very high and it is susceptible to noise. Therefore, an impedance conversion circuit can convert the impedance to about three orders of magnitude lower and output the analog voltage of the light receiving element with high accuracy.

According to the present invention, by using a --dimensional light emitting source,
It is possible to obtain uniform surface emission in the main scanning direction of the light receiving element 'f-1. Even if unevenness occurs, the variation is due to the film thickness distribution between the substrate and the material, so it is a gentle change, and by correcting it in advance with the electrode and light emitting layer shapes, it can be greatly improved over the entire photodetector element. Uniform illuminance can be obtained.

Moreover, all the structures of the present invention can be manufactured by a general-purpose film forming method such as sputtering or low pressure CVD. Moreover, since the EL light emitting source forms a light emitting element with a simple laminated structure of an electrode, an insulating layer, and a light emitting layer, complicated processes such as hot etching are not required, and the source can be manufactured at low manufacturing cost. Alternatively, it may be formed on a cheaper polymer film substrate.

〔Effect of the invention〕

According to the present invention, the light-emitting element and the light-receiving element of the linear light source-integrated contact reading sensor are formed from a linear EL light-emitting source and disposed on the substrate, so that uniform illuminance can be obtained at the light-receiving element, and the reading sensor can be made thin. In addition, it is possible to provide a thinner image reading device equipped with this reading sensor and terminal communication using the device.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a close-contact reading sensor with integrated line light source showing Embodiment 1 of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG.
The figure is a perspective view of a communication terminal equipped with the first embodiment of the present invention.
The figure is a block diagram of a communication terminal, and FIG. 5 is a second embodiment of the present invention.
6 is a block diagram of FIG. 5, FIG. 7 is a cross sectional view of a reading sensor showing Embodiment 3 of the present invention,
FIG. 8 is a cross-sectional view of a reading sensor showing Example 4 of the present invention, FIG. 9 is a graph showing characteristics of a thin film transistor,
FIG. 10 is a diagram showing a comparison of accumulated charge amount depending on pixel density,
FIG. 11 is a diagram showing the circuit of the reading sensor, FIG. 12 is a graph showing the output characteristics of the reading sensor, FIG. 13 is a graph showing the wavelength dispersion characteristics, and FIGS. 14 and 15 are diagrams showing the resolution characteristics. FIG. 16 is a graph showing the output characteristics of a two-color simultaneous reading sensor, and FIGS. 17 to 22 are cross-sectional views of reading sensors showing Examples 7 to 13 of the present invention. DESCRIPTION OF SYMBOLS 1... Light receiving part (light receiving element), 2... Light source part (light emitting element), 3... Light (illumination light), 4... Original, 5... Board,
6... Back electrode, 7... First insulating layer, 8...
EL light source, 9... Second insulating layer, 10... Transparent electrode, 11... Protective layer, 13... Electrode, 14... Moisture resistant resin (sealing material), 15... Light-shielding film.

Claims (1)

[Claims] 1. In an image reading device that includes a light-receiving element and a light-emitting element arranged on a substrate, and a reading sensor that closely scans a document and reads its information, A linear light source integrated close-contact reading formed by a linear light-receiving element provided facing the original, and a light-emitting element provided substantially parallel to the light-receiving element via the substrate and having a linear EL light source. An image reading device characterized by being equipped with a sensor. 2. The line light source integrated contact reading sensor consists of a light receiving element disposed on a first substrate and a light emitting element disposed on a second substrate, and the light emitting element is The light receiving element is attached to the first substrate and sandwiched between the light receiving element and the second substrate, and is disposed at a position where the illumination light emitted passes near the light receiving element. The image reading device according to claim 1. 3. The image reading device according to claim 1 or 2, wherein the line light source integrated contact reading sensor has a light emitting element sealed around the light emitting element with a water-resistant resin. 4. The image reading device according to any one of claims 1, 2, and 3, wherein the linear light source integrated contact reading sensor is characterized in that the electrode on the light receiving element side of the light emitting element is formed of a transparent electrode. . 5. The close-contact reading sensor with integrated linear light source
Claim 1, 2, or 3, wherein the L light emitting source is sandwiched between a pair of transparent electrodes and a back electrode via a first insulating layer and a second insulating layer. The image reading device described. 6. In an image reading device that has a light receiving element and a light emitting element disposed on a substrate, and is equipped with a reading sensor that closely scans a document and reads its information, an optically transparent first substrate is provided facing the document. A linear light-receiving element is provided as a linear light-receiving element, and a second substrate facing the light-receiving element is provided on an end face having an inclination angle, and the inclination angle is set at a position where the illumination light generated by the emission passes near the light-receiving element. An image reading device comprising: a light emitting element having an adjustable linear EL light source; and a close reading sensor integrated with a linear light source. 7. The linear light source integrated close-contact reading sensor uses the light emitting element E
7. The image reading device according to claim 6, wherein the L light emitting source is sandwiched between a pair of opaque electrodes with a first insulating layer and a second insulating layer interposed therebetween. 8. The close reading sensor with integrated linear light source has a light emitting element that
Claim 1, characterized in that the light receiving element is formed of an EL light emitting source, an electrode, and an insulating layer that are continuous in the length direction of the light receiving element.
The image reading device according to any one of items 2 and 3. 9. The linear light source integrated close-contact reading sensor
4. The image reading device according to claim 1, wherein the L light emitting source is branched into a plurality of branches. 10. The linear light source integrated contact reading sensor has an EL light source of a light emitting element sandwiched between a back electrode and a transparent electroluminescent electrode with an insulating layer interposed therebetween, and a light emitting powder is dispersed in an organic binder. 2. The image reading device according to claim 1, wherein the image reading device is formed of a dispersed EL light emitting element, and the periphery of the light emitting element is covered with a package film. 11. The linear light source integrated contact reading sensor is characterized in that the EL light source of the light emitting element is formed of a laminated film of an amine-based organic compound and an organometallic chelate complex, and is driven by a DC circuit of 100 V or less. An image reading device according to any one of claims 1, 2, and 3. 12. The image reading sensor according to any one of claims 1, 2, and 3, wherein the linear light source integrated contact reading sensor is characterized in that the scanning frequency of the light receiving element and the driving frequency of the EL light source are synchronized. Device. 13. In an image reading device having a light receiving element and a light emitting element arranged on a substrate, and equipped with a reading sensor that closely scans a document and reads its information, an optically transparent substrate is provided facing the document. a linear light-receiving element, and a linear EL formed on a convex portion of the back surface of the substrate and formed at a position where illumination light generated by emission passes near the light-receiving element.
An image reading device comprising a close-contact reading device integrated with a linear light source formed by a light-emitting element having a light-emitting source. 14. In the close-contact reading sensor with integrated line light source, the EL light source of the light emitting element is formed of a white EL light emitter, and red, green, and yellow color filters are provided on the surface of the protective film of the light receiving element facing the original. Claim 1 characterized in that:
The image reading device according to any one of items 2 and 3. 15. In the close-contact reading sensor with integrated linear light source, the EL light emitting source of the light emitting element is formed of a white EL light emitter, and the surface of the protective film facing the document of the light receiving element is illuminated with red, red, 4. The image reading device according to claim 1, wherein each of the green and yellow color filters moves. 16. The linear light source integrated contact reading sensor is characterized in that the substrate of the light-receiving element is formed of a glass substrate with a heat-resistant temperature of 600° C. or less, and a drive circuit for scanning the light-receiving element is provided. The image reading device according to any one of items 2 and 3. 17. In the close-contact reading sensor with integrated line light source, the substrate of the light-receiving element is formed of a glass substrate with a heat resistance temperature of 600 degrees Celsius or less, and a wire made of any one of a photodiode, a photoconductor, or a phototransistor is attached to the glass substrate. 2. A thin film circuit comprising: a light-receiving element having a shape; a scanning circuit comprising at least one of a shift register, a level shifter, or a multiplexer; and a thin film circuit comprising an impedance conversion circuit or an analog voltage conversion circuit.
17. The image reading device according to any one of 2, 3, and 16. 18. The close reading sensor with integrated line light source has a thickness of 5 m.
Claims 1, 2, and 3 characterized in that it is formed in m.
or 16. The image reading device according to any one of item 16. 19. The image reading device according to any one of claims 1, 2, and 3, wherein the line light source integrated contact reading sensor has a conductive layer for noise absorption between the light emitting element and the light receiving element. . 20. A close-contact reading sensor with integrated line light source has a light receiving element and a light emitting element disposed on the same substrate, and a lens is provided between each element and the document to prevent illumination light from directly entering the light receiving element. Claim 1 characterized in that:
The image reading device according to any one of items 2 and 3. 21. In the linear light source integrated contact reading sensor, the light emitting material of the EL light source of the light emitting element is ZnS:Mn or SrS:P.
Claim 1, characterized in that it is formed of r, Ce.
The image reading device according to any one of items 2 and 3. 22. In the close-contact reading sensor with integrated linear light source, the EL light source of the light emitting element is formed of a thin film EL, and a threshold voltage of 1 is applied between the output when reading black and the output when reading red or vermilion. , a threshold voltage 2 is set between the output when reading red or vermilion and the output when reading white, and when the threshold voltage is higher than 1, it is a black output, and when the threshold voltages 1 and 2 are 4. The image reading apparatus according to claim 1, wherein a red output is output when the threshold voltage is between 2 and a white output is output when the threshold voltage is 2 or less. 23. The image reading device according to any one of claims 1, 2, and 3, wherein the light emitting material of the light emitting element of the contact reading sensor integrated with a linear light source is locally heat-treated. 24. The image reading device according to any one of claims 1 to 23, wherein a contact reading sensor integrated with a line light source or an integrated reading sensor integrated with a drive circuit is used as the image reading section, and a portable card is used as the information recording section. An image reading device characterized by having a type optical disk memory. 25. A communication terminal comprising an image reading device according to any one of claims 1 to 24, or the device and a communication interface, and a signal processing section, having a portable card-type optical disk memory as a transmission/reception information recording section. A communication terminal characterized in that a contact reading sensor integrated with a line light source or an integrated reading sensor integrated with a driving circuit is used as an image reading section. 26. A communication terminal using the image reading device according to any one of claims 1 to 24.