JP5257280B2 - Image sensor unit - Google Patents

Description

The present invention relates to an image sensor unit used in an image reading apparatus.

An image sensor unit such as a facsimile, a copier, or a scanner is provided with an image sensor unit that irradiates light on a document and reads an image. The image sensor unit is a light source that irradiates light on an image reading position of a document. And an optical system that images reflected light from the document and a sensor that detects the imaged light and converts it into image information.

In such an image sensor unit, it is preferable that the light applied to the document has a light quantity peak in the image reading line of the document. Therefore, as a conventional example, in order to read an image of a document lifted from a document table, it includes a plurality of light guides that guide light from a light emitting element to the document, and the light intensity peak from each light guide is above and below the reading line. There is an image sensor unit in which a step in the vertical direction is provided at the position of the light guide so as to be different in the direction (see, for example, Patent Document 1). In addition, there is a technique that corrects the deviation of the light amount distribution by using a spring and an adjustment screw with respect to an attachment position deviation or an attachment attitude variation when assembling the light source device (see, for example, Patent Document 2).

JP 2004-104480 A JP 2003-163790 A

However, in the above conventional example, the irradiation position is finely adjusted within the range of the reading error of the optical system with respect to the lift of the document or the positional deviation at the time of assembly, and the position of the image reading surface of the document greatly changes. In this case, the irradiation position cannot be adjusted, and it is difficult to obtain image sensor units having different focal positions.

The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an image sensor unit having a different focal position by adjusting the irradiation position according to the position of the image reading surface of the document. .

The image sensor unit according to the present invention is provided so as to be rotatable about a longitudinal axis, and guides light from a light emitting element connected to a light source driving power supply terminal for adjusting a current amount or a light emitting duty ratio in the longitudinal direction. A plurality of columnar light guides that illuminate and irradiate light to the image reading position of the document from the emitting portion formed along the longitudinal direction and the light reflected at the image reading position of the document are condensed and combined. An imaging optical member for imaging, and a sensor for detecting the light imaged by the imaging optical member , wherein the light guides are emitted at an angle corresponding to at least two different image reading positions. It has been adjusted .

According to the present invention, the irradiation position can be adjusted according to the position of the image reading surface of the document by rotating the light guide, and the image reading of the document can be performed by adjusting the current amount of the light emitting element or the light emission duty ratio. Runode can adjust the brightness of the surface, it is possible to easily obtain different image sensor unit focal position.

It is a perspective perspective view which shows the main structures of the image sensor unit which concerns on Embodiment 1 of this invention. FIG. 2 is a development configuration diagram of the image sensor unit in FIG. 1. It is a side view which shows the edge part vicinity of the light guide in FIG. It is a figure which shows the scattering part shape of the light guide in FIG. It is a figure which shows the relationship between the light guide in FIG. 1, and a holder. It is a figure which shows another relationship between the light guide in FIG. 1, and a holder. It is sectional drawing which cut | disconnected the image sensor unit which concerns on Embodiment 1 in the A surface of FIG. FIG. 8 is a diagram in which an interval between an image reading position of a document and a reading optical system in FIG. 7 is changed. FIG. 8 is another diagram in which the distance between the image reading position of the document and the reading optical system in FIG. 7 is changed. 4 is a diagram illustrating a relationship between a light amount and a distance of the image sensor unit according to Embodiment 1. FIG. 6 is a cross-sectional view of an image sensor unit according to Embodiment 2. FIG. 6 is a cross-sectional view of an image sensor unit according to Embodiment 3. FIG. 10 is another cross-sectional view of the image sensor unit according to Embodiment 3. FIG. 6 is a cross-sectional view of an image sensor unit according to Embodiment 4. FIG. 6 is another cross-sectional view of an image sensor unit according to Embodiment 4. FIG. 6 is another cross-sectional view of an image sensor unit according to Embodiment 4. FIG. 10 is a cross-sectional view of an image sensor unit according to Embodiment 5. FIG.

Embodiment 1 FIG.
An image sensor unit 1 used in an image reading apparatus in Embodiment 1 for carrying out the present invention will be described with reference to FIGS. In FIG. 1, an image sensor unit 1 guides light from an LED 12 provided on an end face in a longitudinal direction (referred to as a main scanning direction), and an image of a document from an emitting portion 15 formed along the longitudinal direction. A light guide 2 that irradiates light toward the reading position, and a transmissive imaging optical system 3 that focuses the light reflected at the image reading position of the original to form an image, that is, an imaging optical member And a sensor IC 4 that is provided below the imaging optical system 3 and receives and photoelectrically converts the imaged light and outputs an electrical signal, and a metal or plastic frame 5 that stores these inside. Has been.

As shown in FIG. 2, the light guide 2 faces the image reading surface of the document, and is arranged in a straight line so as to be symmetrical on both sides of the imaging optical system 3. Is fixed to the frame 5 via a holder 10. By arranging in this way, it is possible to suppress unevenness in the amount of light at the image reading position of the document. Further, the imaging optical system 3 is composed of a selfoc lens array or the like that can be easily assembled, and is fitted into a groove 51 formed along the main scanning direction of the frame 5. The sensor IC 4 is placed on a substrate 7 together with electronic components such as a signal processing IC 8 that processes the detected signal. The substrate 7 is fixed to the lower end of the frame 5 by screws, fitted, adhered, or the like. On the other hand, a cover glass 6 formed of a transparent resin such as acrylic or polycarbonate, or a transparent glass material is provided on the upper portion of the frame 5 so as to cover the entire image sensor unit 1 to prevent foreign matter from entering inside. .

Here, the light guide 2 will be described with reference to FIG. The LED 12 provided on the end face of the light guide 2 is electrically connected to the power source terminal 14 for driving the light source via the substrate 13. Further, a scattering portion 11 that scatters light toward a specific direction is provided in a band shape at a position facing the emitting portion 15 formed in the light guide 2. For example, as shown in FIG. 4, the scattering portion 11 has a pyramid-type embossed shape or a saw-toothed prism shape, and is coated with a light-reflecting paint such as a white pigment, roughened, or integrally formed. It is formed by.

The light emitted from the LED 12 is guided in the main scanning direction while reflecting the inside of the light guide 2, and a part of the light scattered by the scattering portion 11 is emitted from the emission portion 15 on the side surface of the light guide 2. The light is emitted and irradiated toward the image reading position of the document. The light scattered at the image reading position of the original is condensed and imaged when passing through the imaging optical system 3 and received by the sensor IC 4. The received light is photoelectrically converted by the sensor IC 4 and then transmitted to the signal processing IC 8 as an electrical signal. The signal processing IC 8 performs image processing in conjunction with the CPU and RAM.
The portion near the end of the light guide 2 and covered with the holder 10 acts as an ineffective area that does not emit light to the outside, and the other portions of the light guide 2 light to the image reading position of the document. It acts as an effective area to irradiate.

A configuration for fixing the light guide 2 will be described with reference to FIG. FIG. 5A shows a cross-sectional view taken along line BB in FIG. 2, and FIG. 5B shows a side view around the end of the light guide 2 from the main scanning direction. The light guide 2 is rotated and adjusted so that the light from the emitting portion 15 irradiates the image reading position of the document, and the end portion in the longitudinal direction thereof is fitted in the hole 17 provided in the holder 10. The screw 16 provided on the holder 10 is fixed horizontally with respect to the image reading surface of the document.

FIG. 5A shows a case where the cross section along the line BB of the light guide 2 is circular, while FIG. 6A shows a case where this cross section is a polygon. As shown in FIG. 6B, the holder 10 is provided with a ring 18 having a groove along the circumference of the hole 17, and the end of the light guide 2 is sandwiched between the holder 10 and the inside of the ring 18. By using the freely rotating spacer 19 and the screw 16 for fixing the spacer 19 by being inserted into the groove of the ring 18, the light guide 2 of any shape can be freely rotated to be irradiated in the irradiation direction. Can be adjusted.

Here, a method for adjusting the image sensor unit 1 will be described.
FIG. 7 is a cross-sectional view of the image sensor unit 1 taken along plane A shown in FIG. The image reading surface of the document is in contact with the cover glass 6, and the focal length of the imaging optical system 3 coincides with the distance between the upper end surface and the image reading position of the document, that is, the focal position. The light guides 2A and 2B are picked by hand, and the end portions of the light guides 2A and 2B are turned around the longitudinal axis in a state where the light guides 2A and 2B are fitted in the holder 10, and the light emitted from each light guide is the image reading position of the document The direction is adjusted so as to be irradiated, and the holder 16 is fixed with the screw 16.

If the focal position of the imaging optical system 3 is, for example, 5 mm and the readable range in the depth direction is about 1 mm, the total amount of light from the light guides 2A and 2B at the image reading position of the document is shown in FIG. As shown, it is larger than the threshold value of the sensor IC 4 and a sufficient amount of light for image reading can be obtained.
At this time, if the rotation axes of the light guides 2A and 2B are aligned with the centers of the light guides, the movable range of the light guides 2A and 2B is reduced, and space saving can be achieved. Further, the irradiation direction can be easily adjusted by providing the scattering portion 11 and the emission portion 15 at positions symmetrical to the rotation axis.

8 is a cross-sectional view of the image sensor unit 1A in which the image reading position of the document is provided above the cover glass 6. As shown in FIG. Since the position of the image reading surface of the document is significantly different from the readable range in the depth direction of the imaging optical system 3, an imaging optical system 3A having an appropriate focal position is used, and the light guides 2A to 2D are respectively used. The light emitted by rotating around the longitudinal axis is adjusted to irradiate the image reading position of the document.

When the focal position of the imaging optical system 3A is 10 mm, the total light amount from the light guides 2A and 2B at the image reading position of the document is smaller than the threshold value of the sensor IC4 as shown in FIG. 10B. Cannot be read. However, the light guides 2C and 2D having the same shape as the light guides 2A and 2B are added to adjust the direction, and the light amounts of the light guides 2C and 2D are maximized when the distance from the document is 10 mm. By adjusting the current amount supply amount of the LED 12 provided at the end, the total light amount is larger than the threshold value of the sensor IC 4 as shown by the solid line in FIG.
The reason why the light amounts of the light guides 2C and 2D are adjusted is to prevent the sensor IC 4 from being irradiated with an excessive amount of light to saturate the sensor output and prevent the image from being read. Instead of adjusting the amount of current supplied to the LEDs 12 provided on the light guides 2C and 2D, the light emission duty ratio of the LEDs 12 can be suppressed so that the amount of light incident within the detection sampling period of the sensor IC 4 is not saturated. good.

Similarly, FIG. 9 is a cross-sectional view of the image sensor unit 1 </ b> B in which the image reading position of the document is provided further above the cover glass 6. Since the position of the image reading surface of the document is significantly different from the readable range in the depth direction of the imaging optical system 3A, the imaging optical system 3B having an appropriate focal position is used, and the light guides 2A to 2F are respectively used. It is adjusted so that the light emitted by rotating around the longitudinal axis is irradiated to the image reading position of the document.

If the focal position of the imaging optical system 3B is 15 mm, the total light amount from the light guides 2A to 2D at the image reading position of the document is smaller than the threshold value of the sensor IC4 as shown in FIG. Although reading is not possible, by further adding the light guides 2E and 2F and adjusting the direction, the total light amount is larger than the threshold value of the sensor IC4 and becomes a value sufficient for image reading.

According to this embodiment, since the irradiation position can be adjusted according to the position of the image reading surface of the document by rotating the light guide, it is possible to easily obtain image sensor units having different focal positions.

In addition, the light guide is provided with a band-like scattering portion at a position facing the emitting portion, so that light can be scattered in a specific direction, and the image reading position of the document can be irradiated.

In addition, the light guide has a longitudinal axis positioned at the center thereof, and by rotating about this axis, the movable range of the light guide can be kept small, and space can be saved.

Further, since a plurality of light guides are arranged in parallel to face the image reading surface of the document, it is possible to secure a necessary and sufficient amount of light for image reading even if the distance to the image reading position of the document is long.

Further, the light guides are arranged symmetrically on both sides of the imaging optical system, so that unevenness in the amount of light at the image reading position of the document can be eliminated.

Embodiment 2. FIG.
In the first embodiment, the light guide 2 has a circular cross section perpendicular to the longitudinal direction. However, in the second embodiment, the light emitting portion 15 is the cylindrical light guide of the first embodiment. Those having a surface with a larger light collecting effect are used. As shown in FIG. 11, the outline of the cross section in the longitudinal direction of the light emitting sections 20A and 20B is part of an ellipse or a radiation shape, so that the spread of the emitted light is suppressed and the image of the original is read. The amount of light at the position can be increased. The light guides 20 </ b> A and 20 </ b> B are not limited to the above shapes and may have a light collecting function, and a lens may be separately provided on the emission unit 15. Other configurations are the same as those of the first embodiment.

The light emitted from the LED 12 is guided in the main scanning direction while being reflected inside the light guides 20A and 20B, and the light scattered by the scattering unit 11 in the direction of the emission part is the side surface of the light guides 20A and 20B. Is emitted toward the image reading position of the document. At this time, the spread width of the emitted light is suppressed by the emitting portion 15 having a surface having a condensing function. Thereafter, similarly to the first embodiment, the light reflected at the image reading position of the document is condensed and imaged when passing through the imaging optical system 3 and received by the sensor IC 4. The received light is photoelectrically converted by the sensor IC 4 and then transmitted to the signal processing IC 8 as an electric signal for image image processing.

As in the first embodiment, the irradiation position can be adjusted according to the position of the image reading surface of the document by rotating the light guide 2, and the number of light guides 2 can be increased or decreased to be necessary for image reading. By securing a sufficient amount of light and changing the imaging optical system 3 to one having an appropriate focal position, image sensor units having different focal positions can be easily obtained.

According to this embodiment, in addition to the various effects described in the first embodiment, the light emitting portion of the light guide has a surface having a condensing function, thereby spreading the light emitted from the light guide. The amount of light at the image reading position of the document can be increased while suppressing the width.

Embodiment 3 FIG.
In the second embodiment, the light-emitting bodies 20A and 20B have the light emitting portions 15 having a condensing surface. In the third embodiment, the light-guiding lens 9 is used as the light-guiding lens 9. 2 and the image reading position of the document. For example, as shown in FIG. 12, the lens 9 may be a lens designed such that the irradiation directions of a plurality of light guides 2A to 2D such as a Fresnel lens coincide with the image reading position of the document, As shown in FIG. 13, another lens may be provided for each of the light guides 2A to 2D. The lens 9 may be fixed to the lower surface of the cover glass 6 or may be integrally formed with the cover glass 6. Other configurations are the same as those of the first embodiment, but the light guides 20A and 20B of the second embodiment may be used.

The light emitted from the LED 12 is guided in the main scanning direction while reflecting the inside of the light guides 2A to 2D, and the light scattered by the scattering unit 11 in the direction of the emission part is side surfaces of the light guides 2A to 2D. The light is emitted from the light emitting portion 15, condensed when passing through the lens 9 provided on the cover glass 6, and applied to the image reading position of the document as light having a small spread width. Thereafter, similarly to the first embodiment, the light reflected at the image reading position of the document is condensed and imaged when passing through the imaging optical system 3 and received by the sensor IC 4. The received light is photoelectrically converted by the sensor IC 4 and then transmitted to the signal processing IC 8 as an electric signal for image image processing.

As in the first embodiment, the irradiation position can be adjusted according to the position of the image reading surface of the document by rotating the light guide 2, and the number of light guides 2 can be increased or decreased to be necessary for image reading. By securing a sufficient amount of light and changing the imaging optical system 3 to have an appropriate focal position, the image sensor unit 1 having a different reading depth can be easily obtained.

According to this embodiment, in addition to the various effects described in the first embodiment, the lens that collects the light from the light emitting portion of the light guide is provided between the light guide and the image reading position of the document. By providing, it is possible to increase the amount of light at the image reading position of the document while suppressing the spread width of the irradiated light.

Embodiment 4 FIG.
In the first embodiment, the light guides 2A to 2D are arranged in a straight line so as to face the image reading surface of the document. In the fourth embodiment, the light guides 2A to 2D are formed in a V shape centering on the imaging optical system 3A. Install side by side. As shown in FIG. 14, the light guides 2 </ b> A to 2 </ b> D are arranged at higher positions as the distance from the imaging optical system 3 </ b> A increases. By arranging in this way, the distance between the light guides 2C, 2D provided at a highly inclined position and the image reading position of the document is reduced, and the amount of light at the image reading position can be increased. The arrangement of the light guides 2A to 2D is not limited to the V shape, and may have a curvature as shown in FIG. Also, as shown in FIG. 16, when the diameter of the cross section perpendicular to the longitudinal direction of the light guide closer to the imaging optical system 3A is reduced, the number of light guides installed is increased and the amount of light at the image reading position is increased. Can do. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

As in the first embodiment, the irradiation position can be adjusted according to the position of the image reading surface of the document by rotating the light guide 2, and the number of light guides 2 can be increased or decreased to be necessary for image reading. By securing a sufficient amount of light and changing the imaging optical system 3 to have an appropriate focal position, the image sensor unit 1 having a different reading depth can be easily obtained.

According to this embodiment, in addition to the various effects described in the first embodiment, the light guide is arranged in a V-shape so as to face the image reading surface of the document, so that the image reading position at the document is read. The amount of light can be further increased.

Embodiment 5 FIG.
In the first embodiment, the transmissive imaging optical system 3 is used, but in the fifth embodiment, the reflective imaging optical system 30 is used. Since the refractive index of light depends on the wavelength, color unevenness caused by the difference in refractive index of light can be suppressed by using a reflective imaging optical system 30 formed of a concave reflecting mirror as shown in FIG. . Since other configurations are the same as those of the first embodiment, description thereof is omitted.

As in the first embodiment, the irradiation position can be adjusted according to the position of the image reading surface of the document by rotating the light guide 2, and the number of light guides 2 can be increased or decreased to be necessary for image reading. By securing a sufficient amount of light and changing the imaging optical system 3 to one having an appropriate focal position, the image sensor unit 1 having a different focal position can be easily obtained.

According to this embodiment, in addition to the various effects described in the first embodiment, color unevenness caused by the difference in the refractive index of light can be suppressed by using the reflective imaging optical system.

1, 1A, 1B Image sensor unit 2, 2A-2F Light guide
3, 3A, 3B, 30 Imaging optical system 4 Sensor IC
5 Frame 51 Groove 6 Cover glass 7 Substrate 8 Signal processing IC
9 Lens 10 Holder 11 Scattering part 12 LED
13 Substrate 14 Power source terminal 15 for driving light source Emitting portion 16 Screw 17 Hole 18 Ring 19 Spacer

Claims (9)

The light from the light emitting element connected to the light source driving power supply terminal that is provided so as to be rotatable about the longitudinal axis and adjusts the amount of current or the light emission duty ratio is guided in the longitudinal direction and along the longitudinal direction. A plurality of columnar light guides that irradiate the image reading position of the original with light from the formed emission portion; and an imaging optical member that focuses and reflects the light reflected at the image reading position of the original; and A sensor for detecting light imaged by the imaging optical member ,
The image sensor unit, wherein the emission directions of the plurality of light guides are adjusted to an angle corresponding to at least two different image reading positions . The image sensor unit according to claim 1, wherein the light guide has a strip-shaped scattering portion formed at a position facing the emitting portion. 3. The image sensor unit according to claim 1, wherein the longitudinal axis is located at the center of the light guide. 4. 4. The image sensor unit according to claim 1, wherein a plurality of the light guides are arranged in parallel to face the image reading surface of the document. 5. The image sensor unit according to claim 4, wherein the light guide is symmetrically disposed on both sides of the imaging optical member. The image sensor unit according to claim 4, wherein the light guides are arranged in a straight line shape or a V shape. The image sensor unit according to claim 1, wherein the emitting portion has a surface having a light collecting action. 8. The optical member according to claim 1, further comprising an optical member for condensing light emitted from the light emitting portion of the light guide between the light guide and an image reading position of the document. The image sensor unit according to any one of the above. The image sensor unit according to claim 1, wherein the imaging optical member is a reflection type.

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