JPS61181259A - Contact type image sensor - Google Patents

Abstract

PURPOSE:To obtain a contact type image sensor where reading density in the main scanning direction is improved by fitting a board provided with a photoelectric converting element onto a piezoelectric element controlled by an application voltage and displacing light receiving part in the main scanning direction. CONSTITUTION:An insulation board 2 provided with the photoelectric converting element 3, a light source 5 irradiating an original 4 and a lens array 6 receiving a reflected light is supported on a base 1 by a support 9. The support 9 consists of the piezoelectric displacing element 10, a spring member 11 and a support 12 supporting the spring member 11 and is arranged at both ends of the board 2. Then an oscillated voltage is applied to the piezoelectric displacing element 10 to oscillate the element 10 and the oscillation direction is made coincident with the main scanning direction 7, that is, the arranging direction of the photoelectric converting elements 3 on the board 2. Thus, in displacing the piezoelectric element 10 by P/2 (where P is a pitch of the photoelectric converting elements 3), the light receiving part is moved by P/2 and a picture with high density is obtained, where the picture element density is doubled substantially.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an image sensor device used in facsimiles and optical character reading devices to read characters and figures on a document in close contact with the document. In particular, the present invention relates to a contact image sensor device configured to obtain a high-resolution image using a one-dimensional contact image sensor having a limited number of pixels.

[Background of the invention]

Photoelectric conversion elements are used for optical reading in facsimile machines, optical character reading devices, and the like.

Conventionally, semiconductor image sensors such as CCD photodiode arrays have been the main photoelectric conversion elements used in this type of reading device. However, since these devices usually use a reduction optical system, the optical path length becomes long, making it difficult to achieve miniaturization. For this reason, recently, in order to reduce the size of the device, a contact type image sensor in which amorphous silicon is sandwiched between a metal electrode and a transparent electrode as a photoelectric conversion element has been proposed.

A conventional example of a device using this close-contact image sensor is Whistle 5.
In the figure, the device includes a photoelectric conversion element (contact line sensor) 3 formed on a substrate 2 mounted on a base 1, and a light source such as an LED that illuminates a document 4. 5 and a lens array 6 that receives reflected light from the original 4 irradiated by the light source 5. The photoelectric conversion element 3 receives the incident light from the lens array 6 and performs photoelectric conversion.

7 is the main scanning direction, and 8 is the sub-scanning direction.

Generally, the resolution of a contact type image sensor device is 2+
The number of pixels that can be formed on the substrate 2 is determined by the number of pixels of the photoelectric conversion element 3 formed on the substrate 2, but the number of pixels that can be formed on the substrate 2 is limited by the fine processing technology of large area photolithography.
There is a limit to the number of photoelectric conversion elements that can be formed, making it difficult to obtain a high-resolution contact type image sensor.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and its purpose is to replace the conventional contact type image sensor (photoelectric conversion element).
An object of the present invention is to provide a high-resolution contact type image sensor/device using the above.

[Summary of the invention]

In order to achieve the above object, the present invention arranges photoelectric conversion elements in a straight line on a substrate, the light irradiated by a light source is reflected on the document, and this reflected light passes through a lens array and is read by the photoelectric conversion element. In the contact type image sensor device, the substrate is straddled on a support having a piezoelectric displacement element that vibrates in the main scanning direction, and the vibration direction of the piezoelectric displacement element on this substrate is straddled in the main scanning direction. Structure 1 in which the photoelectric conversion elements are arranged in a straight line parallel to The feature is that the pitch is smaller than the pitch of , enabling high-level reading.

[Embodiments of the invention]

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a perspective view showing an outline of a contact type image sensor device according to an embodiment of the present invention. In the figure, the contact type image sensor device includes a photoelectric conversion element (contact type line sensor) 3, a light source 5 that irradiates a document 4, and a lens array 6 that receives reflected light of gt f$ 4 irradiated by the light source 5. The device is mainly composed of an insulating substrate 2 and a support 9 for the substrate 2 provided on a base 1+.

The support body 9 supports the piezoelectric displacement element 10. It consists of a spring material 11 and a support body 12 that supports the spring material 11, and is arranged at both ends of the substrate 2. This support 9 consists of two supports 1
A spring material 11 is stretched between the spring members 11, and a stacked piezoelectric element is formed by stacking a plurality of piezoelectric thin plates on both sides of the spring member 11 via electrodes. In this stacked piezoelectric element, adjacent piezoelectric thin plates are polarized in the same direction but in opposite directions, and every other pole is connected in common to form one group of electrodes. By applying a driving voltage between the group of electrodes, the driving voltage is applied to each piezoelectric thin plate, and displacement occurs in the direction of application of this voltage, that is, in the direction of the electric field within the piezoelectric thin film.

Then, this displacement is added up by the number of laminated sheets to deflect the substrate 2 by a predetermined amount. The substrate 2 is attached to the side surface of the laminated piezoelectric displacement element 10 of the support 9 as shown in the figure.
At this time, the vibration direction of the piezoelectric displacement element 10 and the main scanning direction 7
and the arrangement direction of the photoelectric conversion elements 3 on the substrate 2 are set to be equal to each other. In this case, the photoelectric conversion element 3
The arrangement position is the maximum amplitude position (antinode) of the piezoelectric displacement element 10
It is desirable to attach the substrate 2 so that the Further, the light sources 5 and 6 and the lens array 6 are fixed on the substrate 2 in an optically aligned state, and the photoelectric conversion element 3 is disposed below the lens array 6. becomes.

In this embodiment, the electrodes are taken out from the photoelectric conversion element 3 using a conductive pattern (not shown) on the insulating substrate 2.
This is done by connecting the conductive pattern (not shown) on the flexible printed circuit board 13 using, for example, solder. Since the flexible printed circuit board 13 is connected to the reciprocating board 2, it is desirable to form a notch, for example, so as not to hinder the deflection of the board 2.

Next, the operation of the contact type image sensor device having the above configuration will be explained.

As already mentioned, the principle of displacement of the piezoelectric displacement element 10 is to apply a drive voltage to a piezoelectric thin plate and cause displacement in the direction of this voltage application. .05m piezoelectric thin plate is made of Ag-Pd system, P
When 300 sheets of i-Pd, 7, etc. are laminated with electrodes interposed therebetween, the displacement sensitivity is only 20 μm/1ooV, which is insufficient for displacement sensitivity used in an optical reading device.

In contrast to Kosai 1, when the piezoelectric displacement element 10 is formed by breaking 300 similar piezoelectric thin films and electrodes on the side surface of the thin plate-shaped spring material 11 as described above, the piezoelectric displacement element 10 is formed as shown in FIG. A support 9 is obtained which exhibits displacement sensitivity characteristics as shown in FIG. Therefore, the substrate 2, photoelectric conversion element 3, etc. mounted on the support 9 can be displaced with the characteristics shown in FIG.

An example of this displacement (deflection) is shown in FIG. FIG. 3(a) shows a first example in which the light receiving sections 3 of the photoelectric conversion element 3 are arranged in a straight line with an interval of pitch P. For example, after obtaining an image signal at the light receiving section 3a, the piezoelectric displacement A predetermined voltage (second
By applying 1 voltage (which was obtained from the characteristic diagram in the figure), P/
When the piezoelectric element 10 is displaced by Pi2, the substrate 2 and the light receiving section 3a are displaced by Pi2 and come to the position 3b. At this position, the light receiving section 3aK reads the reflected light from the lens array 6. If the light receiving part 3a is moved by Pi2 and read in this way, the reading density will be doubled,
It becomes possible to obtain a highly detailed image that is substantially the same as an image formed with twice the number of pixels.

Therefore, if Towa is applied to an actual reading device,
In addition to main scanning, sub-scanning is added to feed the document, and the third
Assuming that the document feeding (sub-scanning) is P as shown in FIG. At the same time, the original is fed by P and read at the E2 position, and then the voltage application to the piezoelectric displacement element 10 is released and the substrate 2 and light receiving section 3a are returned to their original positions by Pi2.At the same time, the original is fed by P and read again at the E1 position. By repeating the reading operation, it becomes possible to read at twice the reading density of the conventional method. In this case, for example, if the document feed rate is Pi2, the reading density in the sub-scanning direction will also be doubled, resulting in an increased reading density of 4 times.

FIG. 4 shows an operation control method for performing such a reading operation. FIG. 4 (II) shows the relationship between the amplitude of the piezoelectric displacement element 10 and the light receiving position, and FIG. 4 (1)) shows the waveform of the applied voltage when displacing the piezoelectric displacement element 10. , FIG. 4(C) shows the sub-scanning (original feeding) time;
It's a cut. El and E respectively indicate the position of the fluorescent part 3a in FIG. At this time, the piezoelectric displacement element 10 is displaced to the right in the figure by Pi2, and in synchronization with this, sub-scanning is performed and the piezoelectric displacement element 10 is moved by L.

Although the sub-scanning scale is optional, it is usually L=P or L=P/ in accordance with the displacement r- of the piezoelectric displacement element 10.

is often selected. The amount of displacement of the piezoelectric displacement element 10 is proportional to the applied voltage as shown in FIG. This can be done by applying a voltage with a suitable waveform. For example, if synchronization is achieved as shown in Figure 4,
It may also be used as a reference voltage.

In addition, in this embodiment, the amount of displacement of the light receiving portion 3a is expressed as P
An example taken for i2 is explained, but for example, for Pi3
．． It is also possible to read the main scanning direction at three times the density by dividing it into three parts by dividing it into 2 Pi3.
It goes without saying that the sub-scanning density can also be selected from various options in consideration of the main-scanning density.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, a substrate equipped with a photoelectric conversion element, a lens array, a light source, etc. is attached to a piezoelectric conversion element that can be controlled by an applied voltage, and the light receiving part is moved in the main scanning direction. By increasing the reading density in the main scanning direction by displacing the sensor, it is possible to increase the reading density, which was considered difficult using conventional contact type image sensors, and this reading density can be selected as needed. Therefore, it is possible to provide an extremely versatile contact type image sensor device.

[Brief explanation of drawings]

Figures 1 to 4 are for explaining the contact type image sensor device according to the embodiment of the present invention. Figure 3 is a graph showing the relationship between the applied voltage and the displacement of the displacement element.
Figure 3(b) is an explanatory diagram showing the actual reading operation in which sub-scanning is taken into account in the upper 6 displacement. is an explanatory diagram showing the drive waveform of the piezoelectric displacement element and sub-scanning, and FIG. 4(a)
is a graph showing the relationship between the amplitude and time of the piezoelectric displacement element, the fourth
Figure (b) is a graph showing the relationship between frost applied to the piezoelectric transformer and pressure and time, and the fourth and first (C) are sub-scanning (original speed)
FIG. 5 is a perspective view showing an overview of a conventional contact type image sensor device. 1...Base, 2...Substrate, 3...Photoelectric conversion element, 3a...Light receiving window, 4...Original, 5...
..Light source, 6..Length, 7.Main scanning direction, 8..Sub-scanning direction, 9..Support,
10...Piezoelectric displacement element, 11...-Spring material, 1
2...Support, 13...Frame Figure 2 rP force voltage (V) Figure 3 (a) (b) 4 (a) (b) EIE2E
IE2 0/) Pizu+r7)/Ot(C) (Yuyang Tomori-I)

Claims (1)

[Claims] In a contact image sensor device, photoelectric conversion elements are arranged linearly on a substrate, light irradiated by a light source is reflected on a document, and the reflected light is read by each photoelectric conversion element through a lens array. A contact type image sensor device, characterized in that the substrate is provided on a support body having a piezoelectric displacement element, and the photoelectric conversion element is arranged in the main scanning direction.