WO2007119290A1 - ライン状照明装置及びそれを用いた画像読取装置 - Google Patents
ライン状照明装置及びそれを用いた画像読取装置 Download PDFInfo
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- WO2007119290A1 WO2007119290A1 PCT/JP2007/053156 JP2007053156W WO2007119290A1 WO 2007119290 A1 WO2007119290 A1 WO 2007119290A1 JP 2007053156 W JP2007053156 W JP 2007053156W WO 2007119290 A1 WO2007119290 A1 WO 2007119290A1
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- Prior art keywords
- light
- light guide
- illumination device
- reflection
- line
- Prior art date
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Classifications
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
- G03B27/00—Photographic printing apparatus
- G03B27/32—Projection printing apparatus, e.g. enlarger, copying camera
- G03B27/52—Details
- G03B27/54—Lamp housings; Illuminating means
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/024—Details of scanning heads ; Means for illuminating the original
- H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
- H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/024—Details of scanning heads ; Means for illuminating the original
- H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
- H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
- H04N1/0282—Using a single or a few point light sources, e.g. a laser diode
- H04N1/02835—Using a single or a few point light sources, e.g. a laser diode in combination with a light guide, e.g. optical fibre, glass plate
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/024—Details of scanning heads ; Means for illuminating the original
- H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
- H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
- H04N1/02885—Means for compensating spatially uneven illumination, e.g. an aperture arrangement
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/024—Details of scanning heads ; Means for illuminating the original
- H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
- H04N1/02815—Means for illuminating the original, not specific to a particular type of pick-up head
- H04N1/02895—Additional elements in the illumination means or cooperating with the illumination means, e.g. filters
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/024—Details of scanning heads ; Means for illuminating the original
- H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
- H04N1/03—Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array
- H04N1/031—Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array the photodetectors having a one-to-one and optically positive correspondence with the scanned picture elements, e.g. linear contact sensors
- H04N1/0311—Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array the photodetectors having a one-to-one and optically positive correspondence with the scanned picture elements, e.g. linear contact sensors using an array of elements to project the scanned image elements onto the photodetectors
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/024—Details of scanning heads ; Means for illuminating the original
- H04N1/028—Details of scanning heads ; Means for illuminating the original for picture information pick-up
- H04N1/03—Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array
- H04N1/031—Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array the photodetectors having a one-to-one and optically positive correspondence with the scanned picture elements, e.g. linear contact sensors
- H04N1/0315—Details of scanning heads ; Means for illuminating the original for picture information pick-up with photodetectors arranged in a substantially linear array the photodetectors having a one-to-one and optically positive correspondence with the scanned picture elements, e.g. linear contact sensors using photodetectors and illumination means mounted on separate supports or substrates or mounted in different planes
Definitions
- the present invention relates to a line illumination device used in an image sensor unit that irradiates a reading surface of a document and reads reflected light thereof, and an image reading device using the same.
- the contact image sensor (hereinafter abbreviated as CIS) is composed of an illumination device, an equal magnification imaging optical device, a line sensor, and the like.
- a CIS generally has a feature that the optical path length is shorter than that of an image sensor using a reduction optical system, so that a device incorporating the sensor can be easily miniaturized. For this reason, instead of the reduction optical system, it has been widely used in a thin flat bed type image reading apparatus and the like.
- a line illumination device used in CIS it is required that the original surface is illuminated with a necessary illuminance, and the reflected light from the original reaches the line sensor with sufficient intensity.
- FIG. 12 is a cross-sectional view illustrating the configuration of a conventional contact image sensor, and shows a case where the number of light guides 2 is one.
- This close contact type image sensor has a light source unit 1 for irradiating the document 9, and light from the light source unit 1 illuminates the document 9 through the light guide 2. The light thus irradiated is reflected by the document 9, and the light is input to the line sensor 5 formed by a photoelectric conversion element through the lens array 4 and converted into an electric signal.
- reference numeral 3 denotes a frame for supporting the constituent members.
- the line sensor 5 has a plurality of light receiving portions arranged in a plurality of lines that photoelectrically convert an optical image of a document into an electrical signal.
- 6 is a sensor board on which the line sensor 5 is mounted.
- 1 ⁇ r, 1 ⁇ g and 1 ⁇ b are LEDs for illuminating the document 9, and emit red, green and blue colors, respectively. These LEDs are arranged on the end face of the light guide 2 extending in the longitudinal direction.
- the light guide 2 is designed so that the light emitted from each LED is taken in and the amount of illumination light is substantially uniform over the length of one line of the document reading unit.
- 7 connects sensor signals and external devices
- a connector 8 is a transparent glass document support table for supporting the document 9.
- the light emitted from the LED disposed on the end face of the light guide 2 is guided to the acrylic light guide 2 and is emitted to the outside while reflecting the inside of the light in a complicated manner.
- a line-shaped illuminating device in which a light emitting element is provided at one end of an acrylic rod-shaped transparent body and the center position of a reflecting surface and a light source is shifted is used (patent document) 1).
- a light guide having two surfaces with different angles of reflection surfaces inside the light guide is disclosed (Patent Document 2).
- an LED which is a light-emitting element, is arranged only at one end of a rod-shaped transparent body, thereby reducing costs.
- the shape of the light guide is devised, and a uniform illuminance obtained by applying a force to the other end of the LED element is obtained. I am doing so.
- Patent Document 3 two systems of light sources are arranged, and the irradiation position of each light source is shifted up and down on the optical axis of the light receiving element, so that the document is within the range of the depth of field of the imaging means. It describes that the illuminance of the surface should be almost constant. Further, Patent Document 4 describes a light guide body in which a lens array is sandwiched between light guides so that the central portion of the light guide body is bifurcated.
- Patent Document 1 Japanese Patent Registration No. 2693098
- Patent Document 2 Japanese Patent Laid-Open No. 2001-159796 (FIG. 1)
- Patent Document 3 Japanese Patent No. 2848477
- Patent Document 4 Japanese Patent Laid-Open No. 11-266340
- an arrow 1200 indicates the direction of light rays. As shown in the figure, the light beam 1200 is combined with the lens effect on the light exit surface, and becomes a light beam that is condensed at one location of the document 9.
- FIG. 13 is a diagram showing the depth characteristics of the light guide in the image sensor shown in FIG. The illuminance characteristics in the height direction on the support base 8 are shown.
- the vertical axis represents the relative illuminance corresponding to the raised length, with the illuminance on the document support table 8 being “1.0”.
- the horizontal axis indicates the length of the lift from the document support table 8.
- Patent Document 3 there is a method in which the light quantity in the height direction of the document table is leveled by using a two-system light guide and shifting the focal position.
- this requires two light guides and related parts, which is disadvantageous in terms of cost.
- the manufacturing process becomes complicated and the manufacturing load increases because fine alignment of the light guide is required.
- the light guide shown in Patent Document 4 has a bifurcated structure sandwiching the lens array, and has a bilaterally symmetric shape having two reflecting surfaces. However, it has the same structure as the conventional light guide that condenses light at one point on the platen.
- An object of the present invention is to solve the above-mentioned problems of the prior art.
- a feature of the present invention is that it is possible to provide a line-shaped illuminating device that can take a large illumination depth on the reading surface of a document with a single light guide.
- a line illumination device has the following configuration. That is,
- a rod-shaped light guide formed of a transparent material, a light source provided in the vicinity of the longitudinal end surface of the light guide, and a light emitting surface formed on at least a part of the longitudinal side surface of the light guide
- a linear illumination device having
- the cross-sectional structure in the short direction perpendicular to the longitudinal direction of the light guide is A light emitting surface, a plurality of light reflecting surfaces provided at positions facing the light emitting surface, and at least one optical barrier provided at each boundary portion of the plurality of light reflecting surfaces.
- the light exit surface force The emitted illumination light has different condensing points.
- a line illumination device has the following configuration. That is,
- a light guide part that is formed of a transparent material and guides light from a light source provided in the vicinity of a longitudinal end surface of the light guide, and a light output part that radiates light from the light guide part to the outside
- a linear illumination device having a light guide
- the cross-sectional structure in the short direction perpendicular to the longitudinal direction of the light emitting part is
- a plurality of light reflecting surfaces provided at positions facing the light emitting surface and the light emitting surface; at least one optical barrier provided at each boundary portion of the plurality of light reflecting surfaces;
- the illumination width in the sub-scanning direction of the reading surface of the document can be increased by a single light guide, and the illumination depth can be increased. There is an effect that it is possible to satisfactorily capture a document image located at a position away from.
- FIG. 1 is a diagram illustrating a cross-sectional shape of a light guide used in a line illumination device according to an embodiment of the present invention.
- FIG. 2 is a cross-sectional view of a line illumination device using the light guide according to the first embodiment.
- FIG. 3B is a cross-sectional view for explaining that light is propagated in the longitudinal direction of the light guide according to the first embodiment. ⁇ 4A],
- FIG. 4B is a diagram for explaining an optical path image of CIS emission light using the line illumination device according to the first embodiment.
- FIG. 5 is a diagram for explaining illumination depth characteristics of the line illumination device according to the first embodiment.
- FIG. 6 is a diagram for explaining the relationship between the height of the document support table and the illuminance distribution in the sub-scanning direction in the line illumination device according to the first embodiment.
- FIG. 7 is a diagram illustrating a cross-sectional structure of a conventional light guide.
- FIG. 8 is a diagram showing the illuminance distribution characteristics of the conventional light guide shown in FIG.
- FIG. 9C is a diagram showing the shape of the light guide according to Embodiment 2 of the present invention.
- FIG. 10 is a cross-sectional view showing a configuration of a line illumination device using a light guide according to Embodiment 3 of the present invention.
- FIG. 11 is a schematic perspective view showing an image reading apparatus as an application example of the image sensor according to the present embodiment.
- FIG. 12 is a cross-sectional view illustrating a configuration of a conventional contact image sensor.
- FIG. 13 is a diagram showing illuminance characteristics in the height direction with respect to a document in a conventional illumination device.
- FIG. 14 is a diagram for explaining illuminance characteristics according to Embodiment 2 of the present invention.
- the line illumination device is characterized in that it has a plurality of light reflection regions (hereinafter simply referred to as reflection regions) with respect to the structure of a conventional reflection surface.
- FIG. 1 is a diagram for explaining a cross-sectional shape of a light guide 100 used in a line illumination device according to an embodiment of the present invention. Moreover, sectional drawing of the line-shaped illuminating device using this light guide 100 Figure 2 shows. 2 that are the same as those in FIG. 12 described above are denoted by the same symbols, and description thereof is omitted.
- the light guide 100 illuminates the original 9 in a line shape, and provides light for forming an image of the reflected light on the photoelectric conversion element 5 via the lens array 4.
- the light guide 100 according to the first embodiment has a maximum cross-sectional width of about 5 mm and a length of about 22 cm in the longitudinal direction.
- the shape of the light guide 100 according to the first embodiment includes a light exit surface 101 that is a curved surface, reflection regions 102 and 103, side surfaces 104 and 105, and an optical barrier that separates the two reflection regions 102 and 103. Part (hereinafter, simply referred to as a barrier) 106, and surfaces 107 and 108 constituting the part 106.
- the light guide 100 has a substantially fan-shaped cross section perpendicular to the longitudinal direction, and its light exit surface 101 has a convex curved surface with a non-uniform curvature. , 10 3 are formed.
- a light source unit 1 having LEDs of three colors is arranged on or near the end face in the longitudinal direction of the light guide 100 of the linear illumination device according to the first embodiment.
- the light source unit 1 has a force arranged at the end portion in the longitudinal direction of the light guide 100 as in the case of FIG. 12.
- This light guide 100 is as shown in the example of FIG. Since the light guide is not large, the light source unit 1 is provided directly on the side of the light guide 100.
- FIG. 3A and FIG. 3B are cross-sectional views for explaining the propagation of light in the longitudinal direction of the light guide 100.
- the light exit surface 101 of the light guide 100 is a curved surface having a convex cross section provided at a portion facing the reflection regions 102 and 103, and light from the reflection regions 102 and 103 is formed by a convex lens effect. Has a role of emitting light in a predetermined direction. Further, in the reflection regions 102 and 103 of the light guide 100, a minute prism called a knurling as shown in FIGS. 3A and 3B is formed. This small prism functions to scatter light in the longitudinal direction of the light guide 100, or to change the traveling direction of the light and reflect the light in the direction of the light exit surface 101 formed on the opposite surface. Yes. FIG. 3B shows an enlarged view of FIG. 3A. Note that the light from the right shown in FIG. 3B indicates the reflected light having the opposite end force where the light source unit 1 of the light guide 100 is disposed. A reflection member such as an aluminum foil is preferably provided at the opposite end.
- a barrier 106 is formed as a scientific barrier.
- the mixing of the light reflected by the two reflection regions 102 and 103 can be controlled. That is, out of the light reflected by the reflective regions 102 and 103, the light incident on the reflective regions 102 and 103 at a low angle may be reflected by the barrier surfaces 107 and 108 and reach the light emitting surface 101. Can not.
- the reflected light from each of the reflective regions 102 and 103 directly reaches the light exit surface 101 and is emitted therefrom.
- the original 9 can be irradiated.
- the light from the two reflection regions 102 and 103 irradiates the document 9 through different paths. In this way, it is possible to achieve the same effect as in the case where two systems of light guides having different condensing points are arranged.
- the present embodiment is characterized in that the inclination angles of the two reflection regions 102 and 103 are different from each other with respect to the original to be read.
- the angle formed between the side surface 104 and the reflection region 102 is 115 degrees
- the angle of the side surface 107 with respect to the reflection region 102 is 105 degrees
- the angle formed between the side surface 105 and the reflection region 103 is 125 degrees
- the angle formed between the reflection region 103 and the surface 108 is 95 degrees.
- a plurality of protrusions that are minute prisms are formed in the longitudinal direction of the light guide 100.
- 3A and 3B are both cross-sectional views of the reflective region 102 or 103 along the longitudinal direction of the light guide 100.
- the protrusions and the flat portions are alternately arranged along the longitudinal direction of the light guide 100.
- the flat part reflects the light from the light source unit 1 incident on the light guide 100 at an angle of less than the total reflection angle (about 42 degrees in the case of acrylic) according to the reflection principle.
- the light is diffused inside (see Fig. 3A).
- the protrusion has a role of reflecting light parallel to the flat portion in the direction of the light emitting surface 101.
- the reflection regions 102 and 103 have a flat portion and a protrusion, and the surface of the protrusion has an angle with respect to the surface of the flat portion.
- the reflective region used in the present application refers to a flat portion, which has a protruding portion formed for convenience, but is strictly described as a flat end portion and a protruding portion. Point to the whole area!
- FIG. 4A is a view for explaining an optical path image of emitted light inside the light guide according to the present embodiment.
- the light incident on the end face of the light guide 100 from the light source unit 1 repeats reflection inside thereof, is reflected by the reflection regions 102 and 103, and is emitted from the upper light emission surface 101.
- the light guide 100 is formed of transparent acrylic resin.
- the light irradiated to the light guide 100 is reflected to the outside of the light guide 100 by the force incident on the inner side of the light guide due to the refraction of the air and the light guide 100.
- the light traveling from the inside of the light guide 100 toward the outside of the light guide 100 is reflected by the total reflection angle (about 42 °) or less and returned to the inside of the light guide. Angled light is reflected or passed through at a certain rate and is emitted from the light guide 100.
- the light emitted from the light guide 100 can be used as illumination light for the original.
- the light reflected by the side surface 104 and incident on the light emitting surface 101 is reflected by the incident angle to the inside of the light guide 100 and from the light guide 100 to the outside.
- the light is separated from the emitted light, and a part of the emitted light is used as illumination light for the original.
- the light reflected by the side surface 105 and incident on the light emitting surface 101 is incident on the light emitting surface 101 at a high angle, most of the light is emitted to the outside of the light guide 100 and illuminated.
- the radius of curvature of the light emitting surface 101 according to the present embodiment is in contact with the side surface 104 that is large in the vicinity of the side surface 104 with a clear bending point. For this reason, most of the light reflected by the side surface 104 is incident on the light exit surface 101 at a total reflection angle or less. Thereby, the light reflected on the side surface 104 is easily reflected on the inner side of the light guide.
- the radius of curvature of the light emitting surface 101 in the vicinity of the side surface 105 is made smaller than that in the vicinity of the side surface 104 as shown in FIG. 4A.
- the reflection regions 102 and 103 there is light that is not reflected by the side surfaces 104 and 105 in the vicinity thereof and leaks to the outside of the light guide. This is because the reflected light from each reflection region is incident on the side surfaces 104 and 107 on both sides of the reflection region 102 and the side surfaces 105 and 108 on both sides of the reflection region 103 at a high angle with respect to both side surfaces. When the incident angle increases in this way, the reflected light is not reflected on the side surface but is emitted to the outside of the light guide 100 through the side surface and becomes leaked light.
- the angle force between the reflection region and the side surface is S90 ° or less (acute angle)
- this leakage light increases, which is not preferable.
- the amount of light leaking to the outside of the light guide 100 near the reflection region is reduced by making the angle formed between each reflection region and its side surface an obtuse angle (as large as possible). ing. In this way, more reflected light can enter the light exit surface 101.
- the maximum opening angle is a force determined by restrictions such as light collecting conditions as a lighting device.
- FIG. 4B is a diagram showing a schematic configuration of a lighting device using the light guide 100 according to the present embodiment.
- the light emitted from the light exit surface 101 of the light guide 100 is reflected by the document surface.
- the lens array 4 can condense depending on the condensing angle of the lens array 4. . Since this lens array has a condensing angle of several tens of degrees, condensing is limited to the reflected light near the optical axis of the lens array 4.
- the reflected light from the reflection region 102 is incident on the document support table 8 at a low angle and irradiates the document on the document support table 8.
- the reflected light from the reflective area 103 is incident on the document support table 8 at a higher angle than the reflected light from the reflective area 102.
- the reflected light from the reflection region 103 is collected at a high position away from the document support table 8.
- the reflected light from the reflective area 102 serves to lengthen the irradiation range in the sub-scanning direction (left-right direction in FIG. 4B), and the reflected light from the reflective area 103 is located at a high position away from the document support base 8.
- the LED which is the light source
- the LED is disposed at the end surface portion of the light guide 100, and is disposed in close proximity to or near the end surface.
- the position of the light source which is the LED power of the three colors of red, green, and blue, is arranged so that its center (LED 1-g) is approximately at the center of the cross-sectional shape in Figure 1.
- the reflection regions 102 and 103 are formed at two locations, and the angle of the reflection region 102 is slightly smaller than that of the reflection region 103.
- the angle is inclined toward the lens array 4 (Fig. 4B). That is, the normal lines of the reflection areas 102 and 103 are set so as to intersect in the vicinity of the document support table 8. In this way, the reflected light from the light exit surface 102 can be collected more on the document support table 8, the irradiation width in the sub-scanning direction can be widened, and the illumination on the document support table 8 can be increased. Can be raised.
- the reflected light reflected by the reflective region 102 travels straight and is emitted as it is, and light reflected by the side surface 104 and incident on the document support base 8 at a low angle. Become. At this time, the light reflected from the reflection region 102 at a low angle and further reflected by the side surface 104 cannot be directed toward the reflection region 103 because the side surface 107 of the barrier 106 becomes a barrier. Thereby, each light guide part separated by the barrier 106 can function as an independent light guide. Further, by changing the height (depth) of the barrier 106, the light condensing characteristics of the light guide portions can be changed.
- the optical path 400 is such that the light reflected by the side surface 104 of the light guide 100 is at a low angle with respect to the document support base 8.
- An optical path 402 indicates an optical path in which reflected light from the reflection region 102 travels at a low angle ( ⁇ 30 °) with respect to the document support table 8.
- the light irradiated by these optical paths 400 and 402 is reflected by the document and reaches 5 sensor arrays through the lens array 4.
- An optical path 401 is reflected light from the reflection region 103 and is incident on the document support table 8 at a relatively large angle.
- the light in the optical path 403 is reflected by the side surface 105 of the light guide 200 and enters the document support table 8 at a larger angle.
- the reflected light of the light incident on the document support table 8 at an excessively large angle tends to enter the sensor array 5 through the lens array 4.
- the lens array 4 can collect the light only in the range of the limited aperture angle 404. Therefore, the component reflected near the document support table 8 out of the light incident on the document support table 8 at a large angle as in the optical path 401 deviates from the aperture angle 404 of the lens array 4 and is not condensed. Only reflected light from a high altitude position away from the support base 8 is collected. Therefore, the reflected light of the light paths 400 and 402 is collected as reflected light in the vicinity of the document support table 8, and the reflected light of the light paths 401 and 403 is separated from the document support table 8 and floats high. It is collected as reflected light of force.
- FIG. 5 is a diagram for explaining the illumination width and illumination depth characteristics in the sub-scanning direction of the line illumination device according to the first embodiment.
- This figure shows the relationship between the height (d) from the document support 8 and the illuminance with respect to the position of the document surface in the sub-scanning direction.
- 501 is the upper 5 mm from the original support base 8
- 502 is the illuminance in the sub-scanning direction at the upper 10 mm of the original support base 8.
- the illuminance when the contrast on the document support table 8 is “1.0” is indicated by the vertical axis.
- the document support base 8 has two illuminance peaks in the sub-scanning direction, and the width in the sub-scanning direction at which the illuminance is “0.8” or more is about 3 mm.
- the maximum illuminance on the document support base 8 to 5 mm is “approximately 0.7”, and the maximum illuminance on the document support base 8 to 10 mm is “approximately 0.5”.
- the portion with an illuminance of “0.3” or more has a width of about 2 mm even at positions 5 mm and 10 mm above the document support table 8.
- the illuminance in the upward direction of the document support table 8 is markedly improved compared to the comparative example described later.
- the illuminance peak near 1.5 mm in the sub-scanning direction is due to light mainly composed of reflected light from the reflection region 102
- the illuminance peak near Omm in the sub-scanning direction is the reflection region 103. This is due to the light mainly composed of the reflected light. Therefore, the shape of these two illuminance peaks can be changed depending on the width and angle of the reflection regions 102 and 103. For example, by changing the relative angle of the two reflection areas in an acute angle direction, the position where the normal lines of the reflection areas 102 and 103 intersect is changed. In this way, the illuminance at the irradiation position can be increased by bringing the peak positions of the respective illuminances close to each other.
- FIG. 6 is a diagram for explaining the relationship between the height above the document support table 8 and the illuminance in the line illumination device according to the first embodiment. According to FIG. 6, it can be seen that there is an illuminance of about “0.5” even at a position 10 mm away from the document support table 8.
- the normal line passing through the centers of the reflection regions 102 and 103 can be prevented from crossing on the light exit surface side.
- the two illumination peaks in the sub-scanning direction move away from each other, and as a result, the illumination width in the sub-scanning direction can be increased.
- FIG. 14 is a diagram for explaining the illuminance characteristics according to Embodiment 2 of the present invention.
- the illuminance on the document support table 8 when the two reflection regions 102 and 103 are substantially parallel is shown. Specifically, the angle of the reflection region 102 shown in FIG. 1 is changed so as to be substantially parallel to the reflection region 103. As a result, the illuminance peak occurs in the vicinity of 2. Omm in the sub-scanning direction due to the reflected light from the reflective region 102, and the illuminance peak occurs near + lmm due to the reflected light from the reflective region 103. In addition, the area where the illuminance is 0.8 or more in the sub-scanning direction is about 4 mm, indicating that the illuminance width in the sub-scanning direction is wider. Further, in this case as well, as in the first embodiment, the reflected light from the reflecting region 103 is irradiated at a point higher than the document support base 8, so that the illuminance depth in the height direction is increased. Can do.
- the line illumination device using the light guide 100 arbitrarily changes the direction and intensity of the emitted light as if using two light guides. be able to. Further, since the illumination depth is deep, even a document lifted from the document support table 8 can be read by properly irradiating the document 9. As a result, there is an effect that the ratio of being displayed in black when the read original is printed is remarkably reduced.
- FIG. 7 is a diagram for explaining a cross-sectional structure in a short direction of a conventional light guide.
- FIG. 8 is a diagram showing the illuminance distribution characteristics in the sub-scanning direction of the conventional light guide shown in FIG.
- FIG. 13 described above is a diagram for explaining the relationship between the height from the document support table and the illuminance in the line illumination device using the conventional light guide.
- the illuminance decreases as the distance from the document support table 8 increases, and that the light amount distribution when the height is changed is greatly shifted in the sub-scanning direction.
- the attenuation of illuminance increases as the height of the document increases (lifts up). .
- the width in the sub-scanning direction of the illuminance force S “0.8” or more on the document support base 8 is only about 2 mm.
- a single illuminance peak is becoming narrower.
- the illuminance is about half when it is lifted 5mm from the document support base 8.
- the illuminance is almost zero, and it is in a state.
- FIG. 13 is a diagram showing the depth characteristics of the light guide plotted with the illuminance against the distance of the document support table. Comparing FIG. 13 with FIG. 6 described above, it can be seen that in FIG. 13 showing the conventional example, when the lift of the document increases, the illuminance rapidly decreases accordingly.
- the reflection regions 102 and 103 and the side surfaces 104 and 105 may be substantially flat or curved.
- the shape of the reflective regions 102 and 103 is not limited to a flat surface, but can take several deformed shapes.
- FIG. 9A to FIG. 9C shows the shape of the light guide according to Embodiment 3 of the present invention.
- FIG. In the light guide according to the present embodiment, it is important that a plurality of independent reflection regions exist, and as for the shape, several shapes can be selected according to the purpose.
- FIG. 9A is characterized in that the two reflection regions 901 and 902 are both flat. Both ends of each reflection region are curved. That is, at both ends of the reflection region 901, the side surface 903 and the portion connected to the side surface 905 of the barrier 907 are curved. Further, at both ends of the reflection region 902, the side surface 904 and the portion connected to the side surface 906 of the barrier 907 are curved surfaces. As described above, when the corner portion of the reflection region is linearly bent, the side surfaces 104, 107, 108, adjacent to the reflection regions 102, 103 of the light guide body as shown in FIG. Light can easily leak from 105 to the outside. Therefore, by making the corner portion into a curved surface, the corner portion force of the bent portion can also reduce the amount of light leaking to the outside and increase the light utilization efficiency.
- FIG. 9B is a diagram showing a shape of another light guide 910 according to Embodiment 3.
- the reflection areas 911 and 912 are both linear, the angles of the reflection areas are the same, and their normals are parallel.
- the widths of the reflection regions 911 and 912 are different from each other. In accordance with this width, the amount of light incident on the document support table 8 at a low angle to widen the irradiation width in the sub-scanning direction and the amount of light incident at a high angle and illuminating the upper part of the document table are controlled. Can do.
- the width of the reflection region 911 is narrower than that of the reflection region 912. For this reason, of the light reaching the document support table 8, the amount of light irradiated at a low angle is reduced, and the light emitted from the reflection area 912 to the upper part away from the document support table 8 is increased.
- the reflection areas 911 and 912 are both linear, the angles of the reflection areas are the same, and their normals are parallel.
- FIG. 9C is a diagram for explaining another light guide according to the third embodiment, and shows an example of the light guide 920 in which three reflection regions 921 to 923 are formed. These shapes are properly used depending on the illuminance size and depth characteristics required on the document surface.
- At least one of the side surfaces sandwiching the reflection region is a curved surface. It may be. When these surfaces are curved surfaces, the light diffusion Z condensing effect inside the light guide body works due to the lens effect of the mirror surface, and the direction and illuminance of the emitted light can be adjusted.
- the shape of the protrusion shown in FIG. 3A is preferably a sawtooth-shaped convex shape, but may be formed in a groove shape inside the light guide. Furthermore, since the amount of emitted light that also emits the light exit surface force changes depending on the formation density, it is preferable to increase the formation density of these protrusions as the distance from the light source unit 1 increases.
- the reflection area may be further improved in reflection efficiency by applying a metal ink containing an aluminum foil.
- FIG. 10 is a cross-sectional view showing a configuration of a line illumination device using light guide 1000 according to Embodiment 4 of the present invention. Similar to the conventional light guide shown in FIG. 12, the light guide 1000 has a light guide portion 1003 and a light output portion 1002 along its longitudinal direction. Therefore, the cross-sectional view of the lighting device using this light guide 1000 is substantially the same as the cross-sectional shape of the lighting device shown in FIG.
- the light exit unit 1002 receives light from the light guide unit 1003, emits linear light in a predetermined direction from a light exit surface 1001 provided on a part of the light guide unit 1003, and Illuminating the reading portion is similar to the prior art.
- This light guide body 1000 has two reflection areas 1004 and 1005, and as in the first embodiment, enlarges the irradiation area on the document support base 8 and lengthens the illumination depth. .
- FIG. 10 shows an example in which the light guide unit 1003 and the light output unit 1002 are separated.
- a rectangular barrier 1010 having a certain height at the boundary between the light guide unit 1003 and the light output unit 1002, and a wedge barrier 1011 are provided at positions facing the barrier 1010. That is, these barriers 1010 and 1011 play a role of a light amount adjusting valve for the directional light from the light guide unit 1003 to the light output unit 1002.
- the wedge-shaped barrier 1011 has a structure in which the height thereof is changed in the longitudinal direction of the light guide 1000 in accordance with the distance from the light source unit 1. The amount of light entering the light output unit 1002 is controlled along the longitudinal direction of the light guide 1000.
- the reflection regions 1004 and 1005 are reflection regions having different reflection directions, and the emission directions of reflected light from the reflection regions 1004 and 1005 are different from each other. This is the same as in the first embodiment.
- the projections 1010 and 1011 disposed between the light guide unit 1003 and the light output unit 1002 reduce the amount of light once incident on the light output unit 1002 from returning to the light guide unit 1003.
- the illuminance on the document can be increased compared to the conventional example.
- FIG. 11 is a schematic perspective view showing an image reading apparatus which is an application example of the image sensor according to the present embodiment. Here, an example of a flat bed type image reading apparatus using a contact type image sensor is shown.
- reference numeral 111 denotes a CIS provided with the lighting device according to any of Embodiments 1 to 3 described above.
- 112 is a glass plate as a document support (corresponding to the document support table 8 described above), 113 is a wire for operating the CIS, 114 is a drive motor for moving the wire 113 to sweep the CIS 111, and 115 is for the document 9 It is a pressing plate that can be pressed.
- the CIS 111 By rotating the drive motor 114 and mechanically moving the wire 113, the CIS 111 can move in the reading direction (sub-scanning direction) and read the image information of the document.
- the CIS 111 is configured as a sensor unit in which an illumination unit is integrated, and the reflected light from the illuminated document is condensed on the line sensor 5 by the lens array 4 of the CIS 111. As a result, it is output as image information for each line. In this way, it is possible to read an image of a sheet-like document and output the image information.
- the binding portion is less likely to become black even when reading a book, and an easy-to-view image can be provided.
- the illumination device of the present invention can be applied to a device for reading a document, such as a scanner, a facsimile machine, or a copying machine.
Landscapes
- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- General Physics & Mathematics (AREA)
- Facsimile Scanning Arrangements (AREA)
- Light Sources And Details Of Projection-Printing Devices (AREA)
- Facsimile Heads (AREA)
- Image Input (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2008510745A JP4394735B2 (ja) | 2006-03-13 | 2007-02-21 | ライン状照明装置及びそれを用いた画像読取装置 |
CN200780005299.8A CN101385326B (zh) | 2006-03-13 | 2007-02-21 | 线状照明装置以及使用了该线状照明装置的图像读取装置 |
US12/208,035 US8167475B2 (en) | 2006-03-13 | 2008-09-10 | Linear lighting apparatus and image reader using the same |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JPPCT/JP2006/304892 | 2006-03-13 | ||
PCT/JP2006/304892 WO2007105293A1 (ja) | 2006-03-13 | 2006-03-13 | ライン状照明装置及びそれを用いた画像読取装置 |
Related Child Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US12/208,035 Continuation US8167475B2 (en) | 2006-03-13 | 2008-09-10 | Linear lighting apparatus and image reader using the same |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2007119290A1 true WO2007119290A1 (ja) | 2007-10-25 |
Family
ID=38509144
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2006/304892 WO2007105293A1 (ja) | 2006-03-13 | 2006-03-13 | ライン状照明装置及びそれを用いた画像読取装置 |
PCT/JP2007/053156 WO2007119290A1 (ja) | 2006-03-13 | 2007-02-21 | ライン状照明装置及びそれを用いた画像読取装置 |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2006/304892 WO2007105293A1 (ja) | 2006-03-13 | 2006-03-13 | ライン状照明装置及びそれを用いた画像読取装置 |
Country Status (5)
Country | Link |
---|---|
US (1) | US8167475B2 (ja) |
JP (1) | JP4394735B2 (ja) |
CN (1) | CN101385326B (ja) |
TW (1) | TW200746787A (ja) |
WO (2) | WO2007105293A1 (ja) |
Cited By (4)
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JP2011101098A (ja) * | 2009-11-04 | 2011-05-19 | Ushio Inc | 照明装置 |
KR101392519B1 (ko) | 2009-08-21 | 2014-05-07 | 우시오덴키 가부시키가이샤 | 광원 장치 |
WO2014097995A1 (ja) * | 2012-12-20 | 2014-06-26 | 三菱電機株式会社 | 導光体、光源装置及び画像読取装置 |
JP2015022825A (ja) * | 2013-07-17 | 2015-02-02 | パナソニック株式会社 | 照明装置 |
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GB2464742B (en) * | 2008-10-27 | 2011-07-20 | Lobster Pot Photography Ltd | Method and apparatus for 360 degree product photography |
JP5443494B2 (ja) * | 2009-08-21 | 2014-03-19 | 株式会社東芝 | 光学素子および表示装置 |
JP2012015987A (ja) * | 2010-06-02 | 2012-01-19 | Rohm Co Ltd | 線状光源装置および画像読取装置 |
US8576460B2 (en) * | 2011-01-21 | 2013-11-05 | Seiko Epson Corporation | Image reading device |
WO2013042348A1 (ja) * | 2011-09-21 | 2013-03-28 | パナソニック株式会社 | 読取装置 |
JP5963455B2 (ja) * | 2012-01-30 | 2016-08-03 | 三菱電機株式会社 | 照射装置及び画像読取装置 |
JP5655834B2 (ja) * | 2012-09-20 | 2015-01-21 | ウシオ電機株式会社 | 光源装置 |
DE102012111268A1 (de) * | 2012-11-22 | 2014-05-22 | Dr. Ing. H.C. F. Porsche Aktiengesellschaft | Lichtleiter |
US9641714B2 (en) * | 2013-02-21 | 2017-05-02 | Mitsubishi Electric Corporation | Light guide and image reading apparatus |
JP6278761B2 (ja) * | 2014-03-11 | 2018-02-14 | キヤノン株式会社 | 読取制御装置、および、読取制御方法 |
DE102014205363A1 (de) * | 2014-03-21 | 2015-09-24 | Bundesdruckerei Gmbh | Vorrichtung und Verfahren zur optischen Erfassung eines Dokuments und Verfahren zurHerstellung einer solchen Vorrichtung |
US10412255B2 (en) * | 2016-08-30 | 2019-09-10 | Canon Finetech Nisca Inc. | Lighting apparatus and apparatus for reading images |
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Also Published As
Publication number | Publication date |
---|---|
TW200746787A (en) | 2007-12-16 |
CN101385326A (zh) | 2009-03-11 |
JP4394735B2 (ja) | 2010-01-06 |
TWI365658B (ja) | 2012-06-01 |
WO2007105293A1 (ja) | 2007-09-20 |
CN101385326B (zh) | 2013-02-27 |
US8167475B2 (en) | 2012-05-01 |
US20090010020A1 (en) | 2009-01-08 |
JPWO2007119290A1 (ja) | 2009-08-27 |
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