JP3074042B2 - Image sensor and information processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type image sensor mainly used for a document reading apparatus such as a facsimile or a copying machine, and an information processing apparatus used for the same.

[0002]

2. Description of the Related Art A contact type multi-chip image sensor is employed in a document reading apparatus using a conventional short focus imaging element array. For example, in a document reading apparatus as shown in FIGS. 5 to 10, first, a transparent glass plate 201 in contact with the document surface is attached to the upper surface of the box 200, and the emitted light 212 contacts the upper surface of the transparent glass plate 201. The LEDs 211 are provided inside the box 200 in a state where the LEDs 211 are arranged on the substrate 210 at a predetermined angle so as to be reflected on the document surface. Further, an optical system 209 for transmitting the reflected light 213 of the transparent glass plate 201 and a plurality of line sensors 1 provided on the substrate 19 corresponding to the optical system are provided in the box 200. And in the above optical system,
For example, the above-described short-focus imaging element array represented by the product name “SELHOC lens array” (manufactured by Nippon Sheet Glass Co., Ltd.) is employed.

The line sensor 1 is covered with a protective film 206 on the substrate 19, and is covered with a thin metal wire 208.
The board 19 is electrically connected to a desired circuit on the board 9, and the board 19 is supported by a bottom plate 205 engaged with a box via a rubber plate 207. End plates 203 are attached to both ends of the box 200 with screws 204. The box 200 has a connector 20 for input and output of power and control signals outside the facsimile body or the like.
2 are provided.

[0004] Reference numeral 214 denotes an electrode for electrically connecting a desired circuit on the connector 19 to the connector 202.

As shown in FIG. 11, the line sensor 1 has input / output pads 4 and 5 at both ends, and is arranged on the substrate 19 in a straight line from the first to the N-th. A start signal is input from the start signal input line S via the input pad 4 of the first line sensor and an end signal is output via the output pad 5 so that the start signal is sequentially output in accordance with the arrangement order. Activated to read optical information. In this case, when an end signal is output via the output pad 5, the end signal can be input to the input pad 4 as a start signal for the next line sensor. As shown in FIG. 12, each line sensor 1
27 μm (for 200 DPI) or 63.5 μm
(In the case of 400 DPI) at a pitch (here, DPI is an abbreviation of Dot per inch), and alongside this, a drive circuit of a line sensor, a shift register, a power supply input pad, a sensor An area 3 in which output pads and the like are arranged is prepared.

Such a contact-type multi-chip image sensor (indicated by reference numeral 110 in FIG. 14) is provided, for example, at a document reading position of a facsimile via a fixing bracket 109 as shown in FIGS. Is done. here,
A document insertion port 103 is provided at the front edge of the facsimile main body 100.
4, a slit 105 is formed in parallel, and a guide piece 106 for determining the insertion position of the document is slidably provided in the slit 105. A keyboard panel 101 and an operation message display section 107 are arranged on the front upper surface of the facsimile main body 100, and an original take-out port 102 is provided immediately after that.

The original 118 inserted from the original insertion opening 103 is fed via the separation roller 117 to the feeding roller 108.
From there, passes between the platen roller 116 and the image sensor 110, and is discharged to the document take-out port 102.

A roll-shaped recording paper 114 is accommodated at the rear of the facsimile main body 100, and an end thereof is taken out through a platen roller 115. The position of the platen roller 115 Thus, information is recorded by the recording head 111. In the figure,
Reference numeral 112 denotes a facsimile system control board, and reference numeral 113 denotes a power supply unit.

In such a configuration, when reading the original, the line sensor 1 sequentially performs the reading operation from the first to the N-th. During that time, the read data outside the original separated by the guide piece 106 is read out by the facsimile. Is processed and truncated by the system controller.

Here, the case where a multi-chip image sensor is used as the light receiving section has been shown as a conventional example, but there is also a case where the light receiving section is made of another light receiving element such as amorphous silicon.

[0011]

However, the above conventional example has the following problems.

A short focus imaging element array, which is generally a one-to-one optical system, is focused as shown by reference numeral 216 in FIG. 15 and forms an image as shown by reference numeral 217. A reading unit 219 that reads a document on the document passing surface 218 forms an image on the light receiving window 2 of the line sensor 1 along the optical paths 216 and 217.

At this time, in the conventional image sensor, the optical paths 216 and 217 are hollow, and foreign substances such as dust and dust often enter the optical path. in this case,
Light incident on the light receiving window 2 of the line sensor 1 becomes weaker than the original light intensity due to the presence of the foreign matter. In other words, the output signal of the line sensor 1 becomes smaller, so that it becomes a signal closer to black than it should be.

Here, the foreign matter will be described in detail.

In FIG. 15, foreign matters are indicated by reference numerals a, b, c and d. The foreign substance a is attached to the cover glass 201 on the light incident surface side of the optical system 209. The foreign substance b is attached to the optical system 209 on the light incident surface side of the optical system 209. The foreign substance c is attached to the optical system 209 on the light emission surface side of the optical system 209. The foreign substance d is attached to the protective film 206 on the light emission surface side of the optical system 209. These foreign substances a, b, c, and d all exist on the optical path. Here, reference numeral 215 denotes a lens unit (optical path unit) of the short focus imaging element array 209.

Among the foreign substances a, b, c and d, the most problematic foreign substances are a and d. This is because the foreign substances a and d block almost all of the optical paths 216 and 217, but b and c do not block much. That is, the foreign matters that most affect the output decrease of the line sensor 1 are a and d
It is. It is known that foreign matters a and d have a problem with a size of about 50 to 100 μm in diameter, and it is extremely difficult to remove them with the conventional structure.

[0017]

In the present invention, a solution is achieved by disposing a transparent substance at the positions where the optical paths 216 and 217 shown in FIG. 15 are formed so as to prevent foreign matter from entering the optical path.

Further, the information processing apparatus according to the present invention is characterized by including the image sensor and a document holding means for holding a document at a reading position by the image sensor.

[0019]

According to the present invention, it is possible to provide a highly reliable image sensor in which a foreign matter which causes a decrease in the output of the line sensor does not enter the optical path.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 shows a first embodiment of the present invention. In the figure, reference numeral 300 denotes a transparent member disposed on the light incident surface side of the short focus imaging element array 209, that is, between the array 209 and the cover glass 201. The transparent member 300 is adhered to the cover glass 201 using a transparent adhesive (for example, PHOTO BOND # 300 (trade name) manufactured by Sunrise Meisei Co., Ltd.).

In the figure, reference numeral 301 denotes a transparent member disposed on the light emitting surface side of the imaging element array 209, that is, between the array 209 and the protective film 206. The transparent member 301 is also bonded to the protective film 206 using the above-mentioned adhesive. At this time, if the refractive index of the transparent member 300 is made substantially equal to that of the cover glass 201 and the refractive index of the transparent member 301 is made almost equal to that of the protective film 206, the calculation of the optical path length becomes easy.

There is a slight gap between the transparent members 300 and 301 and the imaging element array 209, which focuses the reading unit 219 on the document surface and the light receiving window 2 of the line sensor 1. Imaging element array 209 to match
Is slightly moved up and down in the optical axis direction to adjust. This gap corresponds to the short focus imaging element array 209 to be used.
Although it depends, it is generally preferable to be about 0.3 to 0.5 mm.

According to the above configuration, the most influential foreign substances a and d shown in FIG. 15 are removed, so that the output reduction of the line sensor 1 shown in the conventional example is extremely reduced. The material of the transparent members 300 and 301 is 7059.
(Trade name, manufactured by Corning Co., Ltd.) and polycarbonate.

(Embodiment 2) FIG. 2 shows a second embodiment of the present invention. The second embodiment is characterized in that the transparent member has a lens function. The transparent members 302 and 303 having the lens function use the same transparent members as in the first embodiment, and the bonding method is the same as in the first embodiment.

(Reference Example) FIG. 3 shows a reference example. In this reference example, the transparent member 3
Nos. 04 and 305 are characterized by using a transparent silicone resin as a material. When using a soft resin such as transparent silicone resin as the transparent member,
Since the transparent silicone resin flies elastically, even if the focus adjustment shown in the first embodiment is performed, the transparent members 304, 30
5 follows the imaging element array 209. Therefore, it is not necessary to make the gap for focus adjustment shown in the first embodiment. As a result, the foreign substances a, b, c, and
There is an advantage that all of d does not enter the optical path. In contrast to this reference example, in the above-described embodiment, the distance between the transparent members 300 and 301 and the imaging element array 209 is set to 0.1.
A gap of 3 mm to 0.5 mm is provided, so that a wide variety of transparent materials can be used according to the cost and workability, etc., without using a specific material such as the transparent silicone as the transparent member. The advantage is obtained that can be selected from and used.

FIG. 4 shows an example of the configuration of an electric circuit related to the light receiving element constituting the sensor 1.

[0028] Here, PS is a bipolar transistor that corresponds to one pixel of the reading, SW ₁ is NMOS transistor, SW ₂ is the reference voltage based as a switch means for resetting an emitter connected to a reference voltage source V _ES A PMOS transistor as switch means for resetting by connecting to the source V _BB , SW ₃ is an NMOS transistor as switch means for transferring signal charge, and CT is a capacitive load for generating a signal voltage.

[0029] In such a configuration, at the time of first reset operation, are applied negative pulse voltage to the gate of the PMOS transistor SW ₂ base is clamped to the voltage V _BB.

Next, a positive pulse voltage is applied to emitter voltage source V _ES to the gate of the NMOS transistor SW ₁
And a current flows between the base and the emitter, so that photogenerated carriers remaining in the base disappear.

Next, at the time of the accumulation operation, both the NMOS transistors SW ₁ and SW ₃ are turned off, the emitter and the base are floated, and the accumulation operation is started.

Further, at the time of reading operation, is positive pulse voltage is applied to the gate of the NMOS transistor SW ₃ is turned on, the signal voltage is read to the capacitor CT is connected to the emitter and a capacitor CT is.

The basic configuration of such an image sensor is disclosed in US Pat. No. 4,686,554 issued to Omi and Tanaka, for example, in a bipolar transistor in an output circuit including a capacitive load. Is described as a charge storage type high-sensitivity, low-nozzle photoelectric conversion device to which an emitter is connected.

It is apparent that the image sensor of the present invention can be applied to an information processing apparatus such as a facsimile as shown in FIGS.

As recording means used in the information processing apparatus of the present invention, for example, US Pat. No. 4,723,129,
It is preferable that the typical configuration and principle are disclosed in the specification of Japanese Patent No. 4740796. According to this method, at least one of the electrothermal transducers arranged corresponding to a sheet or a liquid path holding a liquid (ink) and having a rapid temperature rise exceeding each boiling point corresponding to the recorded information is provided. By applying two drive signals, heat energy is generated in the electrothermal transducer and the film is heated on the heat-acting surface of the recording head. As a result, the drive signals correspond one-to-one to the liquid (ink). This is effective because bubbles can be formed. By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed.

Further, as the recording head, a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus can be used, and its form is disclosed in the above-mentioned specification. The configuration may be such that the length is satisfied by a combination of a plurality of recording heads as described above, or a configuration as a single recording head integrally formed.

In addition, the recording head may be of a serial type. The recording head may be fixed to the apparatus main body, or may be attached to the apparatus main body to establish an electrical connection with the apparatus main body or to reduce the number of recording heads. The present invention is also effective when a replaceable chip type which can supply the ink of the above type or a cartridge type in which an ink tank is provided integrally with the recording head itself is used.

[0038]

As described above, according to the present invention, the transparent member is arranged between the original surface (or the cover glass) and the short focus imaging element array and between the run sensor and the short focus imaging element array. It is characterized by. Therefore, according to the present invention, it is possible to realize an image sensor in which a foreign substance that causes a decrease in the output of the line sensor does not enter the optical path.

In the embodiment of the present invention, a multi-chip image sensor using a plurality of line sensors is used as an example. However, there is no problem even if, for example, a sensor using amorphous silicon is used.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention, and is a cross-sectional configuration diagram of an image sensor.

FIG. 2 illustrates a second embodiment of the present invention, and is a cross-sectional configuration diagram of an image sensor.

FIG. 3 shows a reference example of the present invention, and is a cross-sectional configuration diagram of an image sensor.

FIG. 4 is a circuit diagram showing a configuration example of an electric circuit related to a sensor applicable to the image sensor of each configuration.

FIG. 5 is an external perspective view of a conventional image sensor.

FIG. 6 is a perspective view of a sensor section of a conventional image sensor.

FIG. 7 is a longitudinal sectional configuration view taken along line CC of FIG. 6;

FIG. 8 is a perspective view of a substrate having a light emitting unit (LED) of a conventional image sensor.

FIG. 9 is a vertical cross-sectional configuration diagram (along line BB in FIG. 5) of a conventional image sensor.

FIG. 10 is a perspective view showing a partial cross section of a conventional image sensor.

FIG. 11 is a connection diagram of input / output pads of a sensor unit of a conventional image sensor.

FIG. 12 is a plan configuration diagram of a sensor unit of a conventional image sensor.

FIG. 13 is a perspective view of a facsimile having a built-in image sensor.

FIG. 14 is a cross-sectional configuration diagram taken along line DD in FIG.

FIG. 15 is a longitudinal sectional configuration diagram of a conventional image sensor.

[Explanation of symbols]

 209 Short illumination imaging element array 300,301 Transparent member 302,303 Transparent member with lens 304,305 Transparent silicone resin PS Bipolar transistor

Claims (4)

(57) [Claims] 1. A sensor having a protective film for performing photoelectric conversion, a cover glass, and an imaging element disposed between the cover glass and the sensor for forming an image of a document surface on the sensor. An array, and between the imaging element array and the protective film, a first transparent member is provided so as to be in contact with the protective film, and between the imaging element array and the cover glass. And an image sensor provided with a second transparent member so as to be in contact with the cover glass, wherein the distance between the first and second transparent members and the imaging element array is 0.3 mm to 0.2 mm. An image sensor having a gap of 5 mm. 2. The image sensor according to claim 1, wherein the transparent member has a lens function. 3. An information processing apparatus comprising: the image sensor according to claim 1; and a document holding unit configured to hold a document at a reading position of the image sensor. 4. The information processing apparatus according to claim 3, further comprising a recording head that performs recording by ejecting ink using thermal energy.