JPH02161773A - Transmission-type image sensor and picture reader using the sensor - Google Patents

Abstract

PURPOSE:To obtain image information while a reading position is visually confirmed by constituting a leading-out electrode of a transparent conductive substance so that the leading-out electrode forming part can become transparent. CONSTITUTION:A luminous flux reflected by an original to be read is made incident on a transmission type image sensor 2 from a transparent base plate 10 side and reaches a photosensitive section 14 through a transparent leading-out electrode 12. Each picture element in the section 14 produces light carriers of quantities corresponding to the quantity of the incident light. The light carriers become image signals after they are collected through the electrode 12 and comb-shaped leading-out electrodes 20 formed at every picture element. The part between the left edge section of the section 14 and right edge section of a bonding electrode covering section 28 is made to transparent, since the transparent electrode 12 is formed on the transparent base plate 10 in the part. The part between the right edge section of the section 14 and rectangular section 21 of the comb-shaped leading-out electrode 20 has a width of, for example, 1.0mm and is transparent even when the narrow-width section 22 of the opaque electrode 20 exists in the part, since the width of the section 22 is narrower than the 1/4 of the comb-shaped electrode forming pitch of the electrode 20.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a see-through transmission type image sensor and an image reading device using this image sensor.

[Conventional technology]

FIG. 10 is a sectional view of an image reading device using a conventional image sensor, and shows an example of a no-day type image scanner. This image reading device (80) has an opening (72) only on the bottom surface.
) is used. A linear image sensor (9) using an amorphous silicon (a-Si) thin film as a photosensitive part is placed on the bottom of the case top plate, and a linear image sensor (9) is placed on the top of the case top plate directly above this sensor (9). A marker (78) is provided at the position. The image sensor (9) has a strip-shaped photosensitive section, and within this photosensitive section, light receiving elements are formed so as to be arranged one-dimensionally in the longitudinal direction of the photosensitive section. Inside the case (71), a light emitting diode (LED) array (74) and a self-focus lens (SFL) (75) are further arranged. This image reading device (80) is placed on a document (90). A band-shaped light beam (92) emitted from an LED array (74) is irradiated onto a document (90) through an aperture (72), and after being reflected by this document (90), a 5FL (75
), and a one-dimensional array of points on the document (90) forms an image on the image sensor (9). At this time, each light receiving element of the image sensor (9) performs photoelectric conversion, and an electrical signal containing one-dimensional image information is obtained from the sensor (9). By sliding the image reading device (80) over the original (90) in a direction perpendicular to the direction in which the light-receiving elements of the image sensor (9) are arranged, one-dimensional image information can be sequentially obtained. Can read two-dimensional images. However, in case (71) the part to be read is at the time of reading
The reading position could only be known indirectly through the position of the marker (78). This is because even though the substrate on which the photosensitive area is formed is a transparent substrate made of glass, the a-Si thin film is opaque and the surrounding lead electrodes are also opaque, making the entire image sensor (9) almost opaque. This is because, even if the case (71) was provided with a viewing window, the document (90) could not be seen through the image sensor (9). This situation is similar in image reading devices using COD, and a marker is provided on the top or side surface of the case to indirectly confirm the image reading position. [Problems to be Solved by the Invention] As explained above, with conventional image reading devices, it is not possible to directly visually observe the reading position of a document, so it is difficult to accurately determine the reading start and end positions. It was difficult to obtain image information, and necessary parts were sometimes missing or unnecessary parts were included. SUMMARY OF THE INVENTION An object of the present invention is to provide an image reading device that can obtain image information while visually observing a reading position, and a transmission type image sensor suitable for the image reading device. [Means for Solving the Problems] A transmission type image sensor according to the present invention includes a transparent substrate having:
An image sensor comprising a band-shaped photosensitive section and an extraction electrode extending from the longitudinal edge of the photosensitive section in a direction crossing the longitudinal direction while contacting the photosensitive section, the extraction electrode being a transparent conductive electrode. Alternatively, the extraction electrode may be constructed of a comb-shaped opaque conductor so that the extraction electrode forming portion can be seen through. The image reading device according to the present invention is provided with a peephole above the transmission type image sensor, so that the document can be seen through the peephole through the image sensor. [Function] Even when the transmission image sensor according to the present invention is formed on a transparent substrate and the photosensitive portion is made of an opaque material, the portion where the extraction electrode is formed extending from the photosensitive portion, that is, the band-shaped photosensitive portion. The vicinity of can be seen through. Therefore, in the image reading device according to the present invention using this transmission type image sensor, the document can be seen through the image sensor through the peephole, and image information can be obtained while visually checking the reading position. The width of the extraction electrode forming portion that can be seen through is suitably at least five times the width of the photosensitive area. When forming a light-shielding portion to cover the photosensitive portion, the width of the lead-out electrode formation portion that can be seen through is suitably five times or more the width of the light-shielding portion. When extending the lead electrodes from both edges of the photosensitive section, the sum of the widths of both transparent viewing portions may be at least five times the width of the photosensitive section or the light shielding section. In order to make the extraction electrode formed of a comb-shaped opaque conductor so that the extraction electrode forming portion can be seen through, the width of each comb-shaped electrode may be set to one-fourth or less of the comb-shaped electrode formation pitch. [Embodiment] FIGS. 1 and 2 are a partial plan view and a sectional view taken along the line 1--2 of a transmission image sensor according to an embodiment of the present invention, respectively. This transmission type image sensor (2) has a transparent substrate (lO) made of an insulator such as elongated rectangular glass with a width of 4 mm.
An electrode made of a transparent conductive thin film such as ITO5S n 02 is patterned into a rectangular shape as a transparent extraction electrode (12) almost entirely on the upper left half. When using ITO,
Appropriate film thickness is about 800A. A photosensitive portion (14) is formed in the shape of a band with a width of, for example, 200 μm along the longitudinal edge on the right side of the transparent extraction electrode (12). The opaque photosensitive part (14) overlaps a part of the transparent extraction electrode (12), and also slightly protrudes from the longitudinal edge of the transparent extraction electrode (12) to cover a part of the transparent substrate (10) in a band shape. . The photosensitive part (14) is made of amorphous silicon (a-3i), for example, a p layer,
A photodiode with a three-layer structure is constructed by sequentially forming a 1st layer and a 0th layer. However, the structure of the photosensitive section (14) may be any one of a one-layer structure including an i-layer, a two-layer structure including a p-layer and one layer, and a three-layer structure including a p-layer, an i-layer, and a p-layer. After depositing a metal such as Cr on this, the deposited metal film is patterned by a method such as photoetching to form comb-shaped extraction electrodes (20) with a pitch of 125 μm, for example. Each extraction electrode (20) made of an opaque metal film has a shape in which rectangular portions (21, 21) at both ends are connected by a narrow portion (22), and the photosensitive portion (14) is connected from above the photosensitive portion (14). It extends to the right in the figure so as to be orthogonal to the longitudinal direction. Photosensitive part (1
4) The rectangular part (21) formed on the photosensitive part (14)
The width in the direction perpendicular to the longitudinal direction is, for example, 125 μm. This rectangular part (2I) and transparent extraction electrode (12) are
Pixels are formed by sandwiching the photosensitive parts (14). Therefore, the width of each pixel is 125 μm. Narrow part (2
The width of 2) is preferably about 1/4 to 1/6 of the pitch at which the comb-shaped extraction electrodes are formed, and is, for example, 30 μm. The other rectangular portion (23) is for external connection, and a bonding electrode (26) made of, for example, AI is formed thereon as an individual electrode for each pixel. A bonding electrode (27) made of, for example, Al1 is also formed on the left longitudinal edge of the transparent extraction electrode (12) along this edge to constitute an opaque common electrode. This bonding electrode (27) has a covering part (28) parallel to the strip-shaped photosensitive part (14) and extending from the end of this covering part (28) parallel to the comb-shaped extraction electrode (20). Connection part (29
). The light beam reflected by the original to be read is irradiated onto the transmission image sensor (2) from the transparent substrate (10) side, and reaches the photosensitive section (14) through the transparent extraction electrode (12). At this time, each pixel in the photosensitive section (14) generates photocarriers in an amount corresponding to the amount of incident light. The photocarriers are collected through a transparent extraction electrode (12) and a comb-shaped extraction electrode (20) for each pixel, resulting in an image signal. Now, the part between the left edge of the photosensitive part (14) and the right edge of the bonding electrode covering part (28) has a width of, for example, 1.5 mm, and this part is a transparent drawer on the transparent substrate (U). Since the electrode (12) is formed thereon, it can be seen through. The part between the right edge of the photosensitive part (14) and the rectangular part (23) of the comb-shaped extraction electrode (20) has a width of, for example, 1.0 mm, and is an opaque comb-shaped extraction electrode on the transparent substrate (10). (20)
Although there is a narrow portion (22), the width of the narrow portion (22) is one-fourth or less of the comb-shaped electrode formation pitch, so it can be seen through. Therefore, see-through parts with a total width of 2.5 mm are formed on both sides of the 200 μm wide photosensitive portion (14), which is sufficient for seeing through the original. However, both extraction electrodes (12, 20
) is the sum of the widths of the visible parts of the photosensitive area (14).
It is better to double or more. Note that instead of the comb-shaped extraction electrode (20) made of an opaque conductor, the individual electrodes facing the transparent extraction electrode (12) may also be made of a transparent conductor. A comb-shaped extraction electrode (20) is formed on a transparent substrate (10), a photosensitive part (14) and a transparent extraction electrode (12) are sequentially formed on this, and light is incident from the transparent extraction electrode (12) side. It's okay. FIG. 3 is a sectional view of a transmission type image sensor according to another embodiment of the present invention. In addition to the configuration of the transmission image sensor (2) described above, this transmission type image sensor (3) has a photosensitive portion (14) on the rectangular portion (21) of the comb-shaped extraction electrode (20) as a countermeasure against disturbance light. ) is provided with a light shielding layer (30) having a width of 0.4 mm so as to completely cover the area. Therefore, transparent portions approximately six times the width of the light shielding layer (30) are formed on both sides of the light shielding layer (30). However, the sum of the widths of the transparent parts of both extraction electrodes (12, 20) is
The width may be five times or more the width of 0). FIG. 4 is a sectional view of a transmission type image sensor according to still another embodiment of the present invention. The transmission type image sensor (4) according to this embodiment is similar to the transmission type image sensor described above, except that an optical fiber part (32) is embedded in a transparent substrate (IO) under the photosensitive part (14). Different from (2). Optical fiber section (32
) guides the light flux to the photosensitive section (14), so when using this transmission type image sensor (4), there is no need to provide an SFL in the image reading device. FIG. 5 and FIG. 6 are a partial plan view of a transmission type image sensor and its vt-
VT sectional view. In this transmission type image sensor (5), a band-shaped photosensitive portion (14) having photoconductivity is formed directly on a transparent substrate (IO). Reference numerals (40, 50) indicate comb-shaped extraction electrodes made of opaque metal films extending from the left and right edges of the photosensitive portion (14) at a pitch of, for example, 125 μm. The comb-shaped extraction electrode (40) extending to the left has a branch part (41) on the photosensitive part (14).
This branch portion (41) is continuous with a narrow portion (42) having a width of, for example, 30 μm. The length of this narrow portion (42) is, for example, 1.5 mm. Each narrow part (42) has a photosensitive part (1
The portions (43) parallel to 4) are connected to each other as a common electrode. This part (43) continues from the end to a connection part (44) running parallel and backward to the narrow part (42). The comb-shaped extraction electrode (50) extending to the right has a branch part (51) on the photosensitive part (14), and the comb-shaped extraction electrode (4
0) so as not to come into contact with the branch part (41). This branch portion (51) is continuous with a narrow portion (52) having a width of, for example, 30 μm. The length of this narrow portion (52) is, for example, 1. It is Omrn. This narrow portion (52) is continuous with a rectangular portion (53) for external connection. This transmission type image sensor (5) also has see-through portions with a total width of 2.5 mm formed on both sides of the opaque photosensitive portion (14), which is sufficient for seeing through the original. Figure 7 shows the transmission type image sensor (
2) and its driving IC are combined. FIG. This sensor board (7) is constructed by connecting the above-mentioned transmission type image sensor (2) to a separate drive unit (6). The drive unit (8) includes a drive I on the substrate (11).
C (6G) and electrodes (81, 82>), and the substrate (11) is bonded to the transparent substrate (lO) of the transmission type image sensor (2).The bonding electrode of the image sensor (2) (26,27) are bonding wires (
63, 64) and the electrode (62).
60). This driving IC (60) is electrically connected to an external connection electrode (61) via a bonding wire (65). FIG. 8 is a sectional view showing a modified example of the sensor board, and this sensor board (8) has a transmission type image sensor (2).
The transparent substrate (10) is extended, and this substrate (10
) on which are the driving IC (60) and the external connection electrode (61).
is formed. FIG. 9 is a sectional view of an image reading device according to an embodiment of the present invention using the sensor board (8) of FIG. 8, and shows an example of a hand-held image scanner similar to the above. In this image reading device (70), the case (71) not only has an opening (72) on the bottom surface, but also has a peephole (73) on the top plate. A sensor substrate (8) is fixed below the viewing window (73) with the transparent substrate (10) facing downward. Inside the case (71), there is also an LED array (74) and an SF L (75) as before.
and are arranged. The emission wavelength of the LED array (74) is a
A suitable value is 6700 m, which is compatible with the sensitivity of -3i. S
As F L (75), it is preferable to use two rows of 1°1 mm lenses to form an image of about 4 mm width. The light beam (92) irradiated onto the original (90) through the aperture (72) is reflected by the original (90) and then passes through the SF
The light is focused by L (75), and a one-dimensional array of points on the original (90) is imaged onto the photosensitive portion of the transmission type image sensor of the sensor substrate (8). At this time, each pixel performs photoelectric conversion,
An electrical signal containing one-dimensional image information is sent to an image reading device (
70). What's more, if you look down through the viewing window (73), you can see the document (90) through the transmission image sensor.
) can be directly observed. Therefore, by sliding the image reading device (70) while directly confirming the image reading position, a two-dimensional image can be read reliably and neatly. Transmissive image sensors (3, 4, 5) having structures shown in FIGS. 3 to 6 may be used for the image reading device (70), or the sensor substrate (7) shown in FIG. 7 may be used. It's okay. [Effects of the Invention] As described above, the transmission type image sensor according to the present invention includes a band-shaped photosensitive portion on a transparent substrate, and a strip-shaped photosensitive portion that extends from the longitudinal edge of the photosensitive portion in the longitudinal direction while contacting the photosensitive portion. An image sensor formed with an extraction electrode extending in a direction crossing the image sensor, the extraction electrode being made of a transparent conductor,
Alternatively, since the extraction electrode is made of a comb-shaped opaque conductor so that the area where the extraction electrode is formed can be seen through, even if the photosensitive part is made of an opaque material, the vicinity of the photosensitive part can be seen through. be. Therefore, in the image reading device according to the present invention using this transmission type image sensor, the document can be seen through the image sensor through the peephole, and image information can be obtained while visually checking the reading position. In other words, when using the image reading device according to the present invention, the reading start position and end position can be easily and accurately determined, which has the effect of making it possible to read the image reliably and easily.

[Brief explanation of the drawing]

FIG. 1 is a partial plan view of a transmission type image sensor according to an embodiment of the present invention, FIG. 2 is a sectional view taken along ■-■ of the previous transmission type image sensor, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a diagram similar to FIG. 2 of a transmission image sensor according to another embodiment of the present invention; FIG. 5 is a diagram similar to FIG. FIG. 6 is a partial plan view of a transmission image sensor according to another embodiment; FIG. 6 is a sectional view taken along ■-■ of the previous transmission image sensor; FIG. 7 is a transmission image of FIGS. 1 and 2. 8 is a cross-sectional view of a sensor board that combines a sensor and its driving IC; FIG. 8 is a cross-sectional view showing a modification of the sensor board that combines the transmissive image sensor of FIGS. 1 and 2 and its driving IC; FIG. 9 is a sectional view of an image reading device according to an embodiment of the present invention using the previous sensor board, and FIG. 10 is a sectional view of an image reading device using a conventional image sensor. Explanation of symbols 2, 3. 4. 5... Transmissive image sensor, 6
... drive unit, 7. 9...Sensor substrate, 9...Image sensor, 1O...Transparent substrate, I2...Transparent extraction electrode, I4...Photosensitive part, 20...Comb-shaped extraction electrode,
30... Light shielding part, 32... Optical fiber part, 40.
50... Comb-shaped extraction electrode, 60... Drive IC, 70
. . . Image reading device, 71 .
Image reading device, 90... Original, 92... Light beam. Patent applicant Kanebuchi Chemical Industry Co., Ltd.

Claims (1)

[Claims] 1. On a transparent substrate, a strip-shaped photosensitive section and an extraction electrode extending from the longitudinal edge of the photosensitive section in a direction crossing the longitudinal direction while contacting the photosensitive section. What is claimed is: 1. A transmission-type image sensor, characterized in that the extraction electrode is made of a transparent conductor so that the extraction electrode formation portion can be seen through. 2. An image sensor in which a strip-shaped photosensitive section and an extraction electrode that contacts the photosensitive section and extends from the longitudinal edge of the photosensitive section in a direction crossing the longitudinal direction are formed on a transparent substrate. A transmission type image sensor characterized in that the extraction electrode is formed of a comb-shaped opaque conductor so that a portion where the extraction electrode is formed can be seen through. 3. An image reading device comprising: a transmission type image sensor according to claim 1 or 2; a peephole is provided above the sensor; the document can be viewed through the peephole through the image sensor; .