JP6626935B2 - Image sensor head and reading device - Google Patents

Description

  The present invention relates to an image sensor head and a reading device.

2. Description of the Related Art In recent years, an image sensor head that uniformly emits light from a light source to a reading medium has been known. The image sensor head includes a light source, a light guide that guides light emitted from the light source in the main scanning direction, and a light receiving element that receives light emitted from the light guide. 2. Description of the Related Art There is known a light emitting device having an emission part for emitting light and a reflection surface positioned on the opposite side of the emission part (for example, see Patent Document 1). Further, in the image sensor head of Patent Document 1, a triangular blade member is provided on the reflection surface, and the triangular blade member is provided so that the scattering degree of the slope in the main scanning direction is different, so that the illuminance in the main scanning direction is The distribution was close to uniform. There is also known an image sensor head provided with a reference reflector outside an effective reading area and performing white balance correction or gamma correction based on information received by the reference reflector.

JP 2001-61040 A

However, in the above-described image sensor head, an optical path difference occurs between the optical path length from the emission surface within the effective reading area to the reading position and the optical path length from the emission surface to the reading position outside the effective reading area. Therefore, in the conventional image sensor head, the illuminance at the reading position differs from the illuminance at the reading position of the reference reflector, and there is a possibility that an accurate reference value cannot be measured. As a result, accurate correction may not be performed.

An image sensor head according to an embodiment of the present invention includes a light source, a light guide that guides light emitted from the light source in the main scanning direction, a light receiving element that receives light emitted from the light guide, The device includes a reference reflector disposed outside the reading area, and a reference light receiving element that receives light reflected from the reference reflector. Further, the light guide has an emission portion for emitting light, and a first reflection surface and a second reflection surface located on opposite sides of the emission portion. The light guide includes a first portion having a first reflection surface orthogonal to a virtual line connecting the reading position of the reading medium and the emission portion, a reading position of the reference reflection plate, and the emission portion. And a second portion having a second reflection surface orthogonal to a virtual line connecting Further, light emitted from the second portion is reflected by the reference reflector and received by the reference light receiving element.

  A reading device according to an embodiment of the present invention includes the image sensor head described above, and a driving unit that drives the image sensor head or the reading medium in a sub-scanning direction.

According to the present invention, the optical path length from the emission surface to the reading position in the effective reading area can be made closer to the optical path length from the emission surface to the reading position outside the effective reading area.

FIG. 1A is a schematic perspective view showing an image sensor head according to a first embodiment, and FIG. 1B is a schematic perspective view seen from the opposite side of FIG. FIG. 2 is an exploded perspective view of the image sensor head shown in FIG. FIG. 2 is a sectional view taken along the line II shown in FIG. 1. (A) is an explanatory view showing an illuminance distribution near a reading position of a first portion of the light guide, and (b) is an explanatory diagram showing an illuminance distribution near a reading position of a second portion of the light guide. FIG. 2 is a diagram illustrating an illuminance distribution of the image sensor head, wherein a broken line indicates the illuminance distribution of the conventional image sensor head, and a solid line indicates the illuminance distribution of the image sensor head illustrated in FIG. FIG. 1 is a schematic perspective view illustrating a reading device according to a first embodiment. FIG. 7 is an exploded perspective view illustrating an image sensor head according to a second embodiment. FIG. 8 is a sectional view of a second portion of the image sensor head shown in FIG. 7.

<First embodiment>
Hereinafter, the image sensor head X1 will be described with reference to FIGS. Note that R1 shown in the drawing indicates the main scanning direction, and R2 indicates the sub-scanning direction. C1 shown in FIG. 3 indicates a reading position. Further, a two-dot chain line shown in FIG. 4 indicates position information of the reading position C1 shown in FIG. 3, and a one-dot chain line indicates an angle formed between the light guide 11 and a vertical line passing through the reflection surface 12. The dashed line shown in FIG. 4 (b) indicates a virtual line connecting the reading position C1 and the emission unit.

  The image sensor head X1 includes a cover glass 1, a light emitting element substrate 3, a light receiving element substrate 7, a light guide 11, a housing 13, and a lens array 6. The housing 13 is arranged so as to cover the light receiving element substrate 7, and the cover glass 1 is arranged on the upper surface of the housing 13. Further, the light emitting element substrate 3 is joined to the side surface 13 c of the housing 13.

  The cover glass 1 is formed long in the main scanning direction R1, and has a rectangular shape in plan view. The cover glass 1 has a function of protecting each member so that the reading medium P does not contact each member inside the housing 13. The cover glass 1 can be made of a member having a high transmittance, and for example, a plate glass can be used.

  The light emitting element substrate 3 is provided for holding the light emitting element 5. The light emitting element 5 is provided on a side surface of the light emitting element substrate 3, and one end of the light guide 11 is arranged so as to be in contact with the light emitting element 5. The side surface of the light emitting element substrate 3 is disposed to face the side surface 13c of the housing 13, and the light emitting element substrate 3 is disposed in an upright state. The light emitting element substrate 3 can be formed by a PCB substrate, a ceramic substrate, or a glass ceramic substrate.

  The light emitting element substrate 3 has a connection terminal 4 extending downward. As shown in FIG. 1A, the connection terminal 4 extends to a groove 7a provided on the side surface of the light receiving element substrate 7, and the light emitting element substrate 3 and the light receiving element substrate 7 are electrically connected. ing. As a result, a current is supplied to the light emitting element substrate 3 via the light receiving element substrate 7.

  The light emitting element 5 is provided on the light emitting element substrate 3 and functions as a light source that emits light to the reading medium P. The light emitting element 5 can be formed by a light emitting diode (LED).

  The light guide 11 is provided so as to extend in the main scanning direction R1. One end of the light guide 11 is arranged in contact with the light emitting element 3, and is connected to the side surface of the light emitting element substrate 3 by an adhesive or the like. Thereby, the light emitting element substrate 3, the light emitting element 5, and the light guide 11 are integrated to form a light emitting member.

  The housing 13 includes side surfaces 13a and 13b extending along the main scanning direction R1, side surfaces 13c and 13d extending along the sub-scanning direction R2, a light emitting element substrate holding portion 13e holding the light emitting element substrate 3, and a side surface 13c. 13f, a through hole 13g provided in the side surface 13d, and a lens array holding portion 13h holding the lens array 6.

The light emitting element substrate holding portion 13e is provided so as to protrude from the side surface 13c, and has a function of holding the light emitting element substrate 3 provided on the light emitting element substrate holding portion 13e. The light emitting element substrate holding portion 13e has a notch at the center in the sub-scanning direction R2, and the connection terminal 4 of the light emitting element substrate 3 is inserted into the notch.

  The through hole 13f is provided in the side surface 13c, and penetrates the side surface 13c in the main scanning direction R1. The through hole 13g is provided in the side surface 13d, and penetrates the side surface 13d in the main scanning direction R1. One end of the light guide 11 is inserted into the through hole 13f. The other end of the light guide 11 is inserted into the through hole 13g, and as shown in FIG. 1B, the elastic member 2 is connected to the through hole so as to seal the other end of the light guide 11. It is provided within 13 g.

  The elastic member 2 can be formed of a thermosetting resin, a thermosoftening resin, or an ultraviolet curing resin. The elastic member preferably has a Shore hardness of 35 to 55. The elongation at break is preferably 200% or more.

  The lens array holding portion 13h protrudes from the side surfaces 13a and 13b toward the lens array 6. The lens array 6 is sandwiched between a lens array holder 13h projecting from the side surface 13a and a lens array holder 13h projecting from the side surface 13b. The light guide 11 is mounted on the upper surface of the lens array holding unit 13h, and also holds the light guide 11.

  In the lens array 6, a plurality of lenses 6a are arranged in the main scanning direction, and are integrated by a holding member 6b. The lens 6a forms an image of the light reflected from the reading medium P, and supplies the light to the light receiving element 9 located below the lens 6a. As the lens array 6, a gradient index lens array can be exemplified.

  The housing 13 can be formed of a resin material, ceramics, metal, or the like. Note that the inner surface of the housing 13 is preferably roughened so that the lights emitted by the light emitting elements 5 do not interfere with each other, and the housing 13 is preferably formed of a black material so as to absorb the light.

  The light receiving element substrate 7 is provided to hold the light receiving element 9, and is provided to extend in the main scanning direction R1. The edge of the light receiving element substrate 7 along the main scanning direction R1 is covered with the side surfaces 13a and 13b of the housing 13.

  The light receiving element substrate 7 is provided with a groove 7a on one side surface along the sub-scanning direction, and the connection terminal 4 is accommodated in the groove 7a. A part of the wiring provided inside the light receiving element substrate 7 is provided so as to be exposed by the groove 7a. When the connection terminal 4 is accommodated, the light receiving element substrate 7 and the light emitting element substrate 3 are electrically connected. Connected.

  On the upper surface of the light receiving element substrate 7, a plurality of light receiving elements 9 are arranged at predetermined intervals in the main scanning direction R1. The light receiving element substrate 7 can be formed of the same material as the light emitting element substrate 3.

  The light receiving element 9 has a function of photoelectrically converting the light reflected by the reading medium P and converting the light into an electric signal. As the light receiving element 9, a solid-state imaging device can be exemplified, and a CCD image sensor or a CMOS image sensor can be exemplified.

As shown in FIG. 3, the housing 13 has a structure in which an upper space 8a and a lower space 8b are partitioned by a lens array 6 and a lens array holding portion 13h. The upper space 8a is sealed by the lens array 6, the lens array holding portion 13h, and the cover glass 1, and the light emitting element 3 and the light guide 11 are provided inside. The lower space 8b is sealed by the lens array 6, the lens array holding portion 13h, and the light receiving element substrate 7, and a light receiving element 9 is provided inside. As described above, the housing 13 has a box shape with an open top and bottom, and the opening is sealed by the cover glass 1 and the light receiving element substrate 7.

  The light guide 11 will be described in detail with reference to FIGS. FIG. 4 shows the illuminance distribution of the light emitted from the first portion 11a and the second portion 11b, and the illuminance on the line CC indicated by the two-dot chain line indicates the illuminance at the reading position C1. 4A and 4B, the solid line indicates the emitted light, and the dashed line indicates the angle between the light guide 11 and the vertical line passing through the reflection surface 12. Also, the broken line in FIG. 4B indicates a virtual line connecting the reading position C1 and the emission unit. In FIG. 4A, the virtual line is omitted because the emission light and the virtual line overlap. ing. FIG. 5 shows the illuminance distribution on the document surface. The illuminance distribution of the conventional image sensor head is indicated by a broken line, and the illuminance distribution of the image sensor head X1 of the present embodiment is indicated by a solid line.

  The light guide 11 includes a first portion 11a and a second portion 11b as shown in FIG. The first portion 11a and the second portion 11b are formed continuously, and have a substantially cylindrical shape as shown in FIG. Further, as shown in FIG. 3, the light guide 11 has a substantially circular shape in a cross-sectional view, and the reflection surface 12 is provided in a region where a circular arc is partially cut out. The emission section 10 is provided on an arc located on the opposite side of the reflection surface 12.

  The first part 11a has an emission part 10a that emits light, and a reflection surface 12a located on the opposite side of the emission part 10a. As shown in FIG. 4B, the second portion 11b has an emission portion 10b for emitting light, and a reflection surface 12b located on the opposite side of the emission portion 10b. The first portion 11a and the second portion 11b are formed continuously in the main scanning direction R1.

  The light guide 11 has a function of guiding light emitted from the light emitting element 5 in the main scanning direction R1. Then, a part of the light passing through the light guide 11 is reflected by the reflection surface 12, so that the light is emitted from the emission unit 10.

  The light emitted from the light guide 11 has an illuminance distribution having a peak, and the reading position is set by setting the direction of the light guide 11 so that the peak of the illuminance distribution comes to the reading position C1. Accurate reading at C1 is performed. Since the peak of the illuminance distribution in the light guide 11 is formed by light emitted in a direction orthogonal to the reflection surface 12, the reflection surface 12a is positioned between the reading position C1 and the emission position as shown in FIG. In the first portion 11a orthogonal to the virtual line connecting the portion 10a, the peak of the illuminance distribution is provided at the reading position C1.

  That is, the light emitted from the light guide 11 has an illuminance distribution having a peak, and the first portion 11a has an inclination of the light guide 11 such that the peak of the illuminance distribution is at the reading position C1. Is set. The reflection surface 12a of the first portion 11a is inclined with respect to the vertical line, and the angle θa between the reflection surface 11a of the first portion 11a and the vertical line is preferably 35 to 45 °.

  As shown in FIG. 4B, the second portion 11b has a configuration in which the reflection surface 12b is not orthogonal to an imaginary line connecting the reading position C1 and the emission portion 10b. In other words, when viewed in the main scanning direction, it is provided so as to be inclined with respect to the first portion 11a. That is, the second portion 11b is inclined with respect to the first portion 11a when viewed in the main scanning direction. Therefore, in the second portion 11b, when the reflection surface 12b is inclined with respect to the vertical line, and when the reflection surface 11b of the second portion 11b is at the angle θb between the vertical line, the angle θb formed by the angle θb is smaller than the angle θa formed by the angle θb. Is also growing.

Therefore, light emitted in the direction orthogonal to the reflection surface 12 of the second portion 11b, which is the peak of the irradiation distribution, is emitted to the right of the reading position C1 as shown in FIG. 4B. . Therefore, the illuminance of the second portion 11b at the reading position C1 is lower than the peak, and the illuminance of the second portion 11b is lower than the illuminance of the first portion 11a. That is, the second portion 11b can adjust the illuminance of the emitted light by adjusting the inclination with respect to the first portion 11a. Thereby, the illuminance distribution in the main scanning direction can be made nearly uniform. It is preferable that the angle θb be greater than the angle θa by 1 to 10 °.

  Further, since the illuminance of emitted light can be adjusted without providing a complicated reflection pattern on the reflection surface 12, the possibility that reflection in the main scanning direction is caused by the reflection pattern can be reduced. In addition, even at a position far from the light emitting element 5, the possibility that the light amount becomes insufficient can be reduced.

  Here, as shown by the broken line in FIG. 5, in the conventional image sensor head, the light amount becomes insufficient as the distance from the light emitting element 5 increases, and the illuminance distribution on the document surface may vary.

  On the other hand, in the image sensor head X1, the light emitting element 5 is connected to one end of the light guide 11 in the main scanning direction, the second portion 11b is arranged on the light emitting element 5 side, and the light emitting element 5 is close to the light emitting element 5. The reflection surface 12b of the second portion 11b disposed at a lower angle than the reflection surface 12a of the first portion 11a can lower the illuminance on the light-emitting element 5 side with high illuminance. Thereby, the illuminance distribution in the main scanning direction can be made nearly uniform. Further, even at a position far from the light emitting element 5, the possibility that the light amount becomes insufficient can be reduced.

  As a result, as shown by the solid line in FIG. 5, the illuminance can be reduced by the second portion 11b in the portion closer to the heating element 5 than the conventional image sensor head shown by the broken line, In a portion far from the element 5, a decrease in the amount of light can be suppressed, and the illuminance can be increased. As a result, the light amount distribution in the main scanning direction R1 can be made nearly uniform.

  The light guide 11 can be formed of a transmissive member, and can be formed of, for example, glass or resin. When the light guide 11 is formed of resin, it can be formed by injection molding. Further, the light guide 11 may be created by cutting a plate-made material.

  The image sensor head X1 reads the reading medium P by the following operation.

  First, the image sensor head X1 drives the light emitting element 5 to emit light from the light emitting element 5. The light emitted from the light emitting element 5 travels inside the light guide 11 in the main scanning direction R1, is reflected by the reflection surface 12, and is emitted from the emission unit 10. The light emitted from the light guide 11 is reflected by the reading medium P at the reading position C, and the reflected light is imaged by the lens array 6 and supplied to the light receiving element 9. As a result, the image sensor head X1 reads the reading medium P by converting the image information of the reading medium P into an electric signal via the light.

  FIG. 3 schematically shows an optical path, and in practice, some light may be refracted or reflected by the cover glass 1 in some cases.

  Further, although an example has been shown in which the angle θb formed by the reflection surface 12b of the second portion 11b is larger than θa of the first portion 11a, it may be smaller. Also in that case, the peak of the illuminance shifts to the left from the reading position C1, and the illuminance of the light emitted from the second portion 11b can be reduced.

  The reading device Y1 including the image sensor head X1 will be described with reference to FIG.

  The reading device Y1 is configured by a main body 41 including each member described below, and a lid 42. The main body 41 includes therein a carriage 43 having the image sensor head X1 and a guide rail 44 for fixing the carriage 43. Further, the main body 41 includes therein a stepping motor 45 for driving on the guide rail 44, a driving belt 46 connected to the stepping motor 45, and a control unit 35 for performing drive control. A document table 47 on which a document is placed is provided on the upper surface of the main body 41.

  The control unit 35 controls the driving of the stepping motor 45 based on a signal sent from the outside. The control unit 35 includes a CPU or a microcomputer, and is incorporated in a circuit of the stepping motor 45. Note that the control unit 35 may not be incorporated in the circuit of the stepping motor 45.

  The reading device Y1 reads an image or the like line by line by a width of one pixel by moving the image sensor head X1 (carriage 43) in the sub-scanning direction R2. The drive unit (not shown) includes the above-described guide rail 44, stepping motor 45, drive belt 46, and control unit 35. As the reading device Y1, a facsimile, a scanner, or a composite machine thereof can be used.

  In the reading device Y1, an example in which the image sensor head X1 is driven has been described, but the present invention is not limited to this. The image sensor head X1 may be fixed to the multifunction peripheral, and the stepping motor 45 may drive the reading medium 23 in the main scanning direction R1.

<Second embodiment>
The image sensor head X2 will be described with reference to FIGS. In FIG. 7, the cover glass 1 is indicated by broken lines for easy understanding. Further, in FIG. 8, for ease of comparison, the first portion 111a and the optical path of light emitted from the first portion 111a are indicated by broken lines. The optical path of the light emitted from the second portion 111b is shown by a solid line.

  In the image sensor head X2, a light guide 111 arranged on the light emitting element substrate 3 is different from the light guide 11 of the image sensor head X1. Further, a reference reflection plate 14 and a reference light receiving element 16 are further provided. Other points are the same as those of the image sensor head X1. The same members are denoted by the same reference numerals, and the same applies hereinafter.

  The image sensor head X2 includes, in addition to the cover glass 1, the light emitting element substrate 3, the light receiving element substrate 7, the light guide 111, the housing 13, and the lens array 6, a reference reflecting plate 14 and a reference light receiving element. 16 is further provided.

  The light guide 111 includes a first portion 111a and a second portion 111b. The first portion 111a is formed in the light guide 111 located inside the effective reading area, and the light guide 111 is located outside the effective reading area. Is formed with the second portion 111b.

  The reference reflection plate 14 is provided outside the effective reading area of the image sensor head X2, and is disposed in the upper space 8a (see FIG. 3) surrounded by the cover glass 1 and the housing 13. More specifically, the reference reflection plate 14 is provided on the surface of the cover glass 1 and provided on the lower surface of the cover glass 1 via an adhesive (not shown). The concept that the light guide 111 is provided on the surface of the cover glass 1 is a concept including that it is provided via an adhesive as illustrated. The adhesive need not always be provided.

The reference reflection plate 14 can be formed of a member having a high reflectance, and for example, a white resin plate can be used.

  The light emitted from the second portion 111b is reflected by the reference reflector 14, formed into an image by the lens array 6, and received by the reference light receiving element 16. Note that the reference light receiving element 16 is formed of the same member as the light receiving element 9.

  The image sensor X2 performs white balance correction or gamma correction based on information received by the reference light receiving element 16.

  In order to perform the above correction, it is necessary to provide a reference reflector 14 and measure a reference value serving as a reference. However, when the reference reflector 14 is provided inside the effective reading area, the reference reflector 14 is provided. There is a problem that the reading medium P cannot be read in the region where the reading has occurred. Therefore, the reference reflection plate 14 is provided outside the effective reading area. Note that the effective reading area indicates an area where the light receiving element 9 is provided, and is indicated by a broken line in FIG.

  Here, when the reference reflector 14 is provided outside the effective reading area, the optical path length La from the emission surface 110a of the first portion 111a to the reading position C1, and the optical path length La from the emission surface 110b of the second portion 111b to the reading position C2. An optical path difference occurs with the optical path length Lb. Therefore, in the conventional image sensor head, the illuminance at the reading position C1 is different from the illuminance at the reading position C2 of the reference reflection plate 14, and there is a possibility that an accurate reference value cannot be measured. As a result, accurate correction may not be performed.

  On the other hand, the image sensor head X2 has a configuration in which light emitted from the second portion 111b is reflected by the reference reflection plate 14, and the reflected light is received by the reference light receiving element 16. Therefore, by inclining the second portion 111b with respect to the first portion 111a so that the optical path length Lb becomes equal to the optical path length La, the optical path length Lb can be made equal to the optical path length La. The optical path length La indicates the optical distance from the emission surface 110a to the reading position C1, and the optical path length Lb indicates the optical distance from the emission surface 110b to the reading position C2.

  Further, the reference reflection plate 14 is disposed in the upper space 8 a surrounded by the cover glass 1 and the housing 13. Thereby, the configuration for performing the correction can be completed inside the image sensor head X2, and it is not necessary to change the configuration of the light guide 111 for each reading device in which the image sensor head X2 is mounted. In addition, the configuration of the reading device can be simplified.

  Furthermore, since it is arranged in the upper space 8 a surrounded by the cover glass 1 and the housing 13, the reference reflector 14 is sealed by the housing 13 and the cover glass 1. Thereby, the possibility that the reference reflecting plate 14 is damaged can be reduced. Further, the possibility that dust and the like adhere to the reference reflection plate 14 can be reduced, and accurate correction can be performed.

  Further, a reference reflector 14 is provided on the surface of the cover glass 1. Therefore, the reference reflection plate 14 is firmly fixed to the housing 13, and the light reflected by the reference reflection plate 14 can be accurately received by the reference light receiving element 16.

  In the second embodiment, an example in which the reference reflection plate 14 is provided on the lower surface of the cover glass 1 has been described, but the present invention is not limited to this. For example, the reference reflection plate 14 may be provided on the upper surface of the cover glass 1. Further, the reference reflecting plate 14 may be provided in the reading device. Also in these cases, the optical path length Lb can be made equal to the optical path length La by adjusting the inclination angle of the second part 111b with respect to the first part 111a.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various changes can be made without departing from the gist of the present invention.

  For example, although the reading device Y1 using the image sensor head X1 has been described, the reading device Y1 using the image sensor head X2 may be used. Further, the embodiments X1 and X2 may be arbitrarily combined, and the combination of these embodiments is also considered to be described in the present specification.

X1 to X2 Image sensor head Y1 Reading device P Reading medium 1 Cover glass 3 Light emitting element substrate 5 Light emitting element 7 Light receiving element substrate 9 Light receiving element 10 Outgoing part 11 Light guide 11a First part 11b Second part 12 Reflecting surface 13 Housing 14 Reference reflector 16 Reference light receiving element 45 Driver

Claims (5)

A light source,
A light guide that guides light emitted from the light source in the main scanning direction,
A light-receiving element that receives light emitted from the light guide and reflected by the reading medium;
A reference reflector disposed outside the effective reading area,
A reference light receiving element that receives light reflected from the reference reflector,
The light guide has an emission unit that emits light, and a first reflection surface and a second reflection surface located on opposite sides of the emission unit,
The light guide,
A first portion having a first reflection surface orthogonal to an imaginary line connecting the reading position of the reading medium and the emission unit;
A second portion orthogonal to an imaginary line connecting the reading position of the reference reflector and the emission portion ;
An image sensor head, wherein light emitted from the second portion is reflected by the reference reflector and received by the reference light receiving element. A box-shaped housing for housing the light receiving element and the light guide, and a cover glass provided to cover an opening of the housing,
The image sensor head according to claim 1, wherein the reference reflection plate is disposed in a space surrounded by the housing and the cover glass.   The image sensor head according to claim 2, wherein the reference reflection plate is provided on a surface of the cover glass. The light source is provided on one end side of the light guide in the main scanning direction,
4. The image sensor head according to claim 1, wherein the reference reflection plate is disposed on the other end side of the light guide. 5. An image sensor head according to any one of claims 1 to 4,
A driving unit for driving the image sensor head or the reading medium in a sub-scanning direction.

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