WO2008032588A1 - Procédé et dispositif d'éclairage de document et lecteur d'image - Google Patents

Procédé et dispositif d'éclairage de document et lecteur d'image Download PDF

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Publication number
WO2008032588A1
WO2008032588A1 PCT/JP2007/067009 JP2007067009W WO2008032588A1 WO 2008032588 A1 WO2008032588 A1 WO 2008032588A1 JP 2007067009 W JP2007067009 W JP 2007067009W WO 2008032588 A1 WO2008032588 A1 WO 2008032588A1
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WO
WIPO (PCT)
Prior art keywords
light
illumination
imaging
lens
light source
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Application number
PCT/JP2007/067009
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English (en)
Japanese (ja)
Inventor
Satoshi Yamauchi
Original Assignee
Oisllee Planning Co., Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Oisllee Planning Co., Ltd filed Critical Oisllee Planning Co., Ltd
Priority to JP2008534290A priority Critical patent/JP4438015B2/ja
Publication of WO2008032588A1 publication Critical patent/WO2008032588A1/fr

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Classifications

    • 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
    • H04N1/02845—Means for illuminating the original, not specific to a particular type of pick-up head using an elongated light source, e.g. tubular lamp, LED array
    • H04N1/0285—Means for illuminating the original, not specific to a particular type of pick-up head using an elongated light source, e.g. tubular lamp, LED array in combination with at least one reflector which is in fixed relation to the light source
    • 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
    • H04N1/02845—Means for illuminating the original, not specific to a particular type of pick-up head using an elongated light source, e.g. tubular lamp, LED array
    • H04N1/02865—Means for illuminating the original, not specific to a particular type of pick-up head using an elongated light source, e.g. tubular lamp, LED array using an array of light sources or a combination of such arrays, e.g. an LED bar
    • 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
    • H04N1/0289—Light diffusing elements, e.g. plates or 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
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/10—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces
    • H04N1/1013—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using flat picture-bearing surfaces with sub-scanning by translatory movement of at least a part of the main-scanning components
    • 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
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/19—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays
    • H04N1/191—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa using multi-element arrays the array comprising a one-dimensional array, or a combination of one-dimensional arrays, or a substantially one-dimensional array, e.g. an array of staggered elements
    • H04N1/192—Simultaneously or substantially simultaneously scanning picture elements on one main scanning line
    • H04N1/193—Simultaneously or substantially simultaneously scanning picture elements on one main scanning line using electrically scanned linear arrays, e.g. linear CCD arrays

Definitions

  • the present invention relates to a document illumination method, a document illumination device, and an image reading device.
  • Patent Document 1 discloses an image reading apparatus that reads reflected image from a document illuminated by a light source onto an imaging element with an imaging lens and reads the image of the document.
  • an image reading apparatus characterized in that the light source is provided at a position that overlaps a part of an effective pupil of the imaging lens when the imaging lens is viewed! .
  • Patent Document 2 discloses an image reading apparatus that illuminates a document surface with a one-dimensional light source and scans the document to read a document image line-sequentially with a one-dimensional imaging device and an imaging lens.
  • a half mirror that guides the light from the one-dimensional light source to the imaging lens between the imaging element and the imaging lens, and the perpendicular of the document surface coincides with the optical axis of reading by the imaging lens.
  • An image reading apparatus characterized in that the optical system is configured so as not to occur is disclosed.
  • FIGS. 1A and 1B are a schematic view of a general image reading apparatus and a cross-sectional view of the image reading apparatus in the sub-scanning direction, respectively.
  • an original (107) such as a sheet and a book is placed on a contact glass (original table) (108) made of transparent glass, and the light from the illumination lamp (109) and Light reflected from the reflector (110) receiving light leaked from the illumination lamp (109) is applied to the imaging area (Ai) of the document (107).
  • the illumination lamp (109) is, for example, a cold cathode tube, and a part of the tube wall is a window. The light from the illumination lamp (109) is applied to the imaging area (Ai) of the document (107) through the window.
  • the first traveling body (103) integrally includes an illumination lamp (109), a reflector (110), and a turning mirror (112), and the second traveling body (104) includes a folding mirror A (l 11a) and folding mirror B (11 lb).
  • the reflected light from the imaging region (Ai) is reflected by the turning mirror (112) in the first traveling body (103), the folding mirror A (11 la) and the folding mirror B (in the second traveling body (104).
  • 11 lb) and is imaged on the one-dimensional image sensor (101) by the imaging lens (102).
  • the folding mirror A (l 11a) and the folding mirror B (11 lb) maintain the direction of the image of the reflected light from the turning mirror (112).
  • the imaging lens (102) is generally an optical system including a plurality of lenses integrated by a lens barrel.
  • the one-dimensional imaging device (101) acquires a one-dimensional image of the line-shaped imaging region (Ai) and converts it into an electrical signal.
  • the direction in which the one-dimensional image sensor (101) acquires this one-dimensional image is called the main scanning direction (Sx).
  • a system including the imaging lens (102) and the one-dimensional image sensor may be referred to as a reading unit.
  • the reading area of the document (107) is the product of the range read by the one-dimensional imaging device (101) and the traveling distance of the second traveling body (104).
  • a direction in which the first traveling body (103) and the second traveling body (104) travel in parallel with the contact glass (108) is referred to as a sub-scanning direction (Sy).
  • the sub-scanning direction (Sy) is orthogonal to the main scanning direction (Sx).
  • a one-dimensional CCD (sometimes simply referred to as a CCD) is used as a one-dimensional imaging device, and the imaging lens (102) reduces the image on the surface of the contact glass (108), and The reduced image is formed on the one-dimensional image sensor (101).
  • the moving distance of the second traveling body (104) is Half of the travel distance of the first traveling body (103), from the imaging area (Ai) to the imaging lens (102) or the one-dimensional imaging device (101) Is constant regardless of the positions of the first traveling body (103) and the second traveling body (104).
  • a monochrome scanner uses a single one-dimensional CCD, and the image resolution of the scanner is expressed in DPI (dots / inch), and the image resolution of the scanner installed in a digital PPC. Is often 400-600 DPI.
  • color scanners use three one-dimensional CCDs that are sensitive to the spectrum of R (red), G (green), or B (blue) light. It is common.
  • a three-line CCD with a color filter for lateral force, sinusoidal force (red), G (green) or B (blue) arranged in the sub-scanning direction (Sy) is used as the image sensor. Sometimes.
  • the distance between the pixel columns is about 4 to 8 dots in the main scanning reading area of the CCD pixel, and the pixel columns are not necessarily integrated. Therefore, when a 3-line CCD is used as the image sensor of the image reading device, the reading position of the original corresponding to each of the RGB CCD pixels differs in the secondary scanning direction (Sy). It is necessary to irradiate the reading position corresponding to each color.
  • FIG. 2 is a diagram for explaining one of the problems related to illumination of a document in the image reading apparatus.
  • the light generated in the cold-cathode tube illumination lamp (201) mounted on the first traveling body of the image reading device is reflected by the fluorescent screen (202) and passes through the opening (203) of the cold-cathode tube. , Emitted as illumination light (204).
  • the illumination light (204) emitted from the illumination lamp (201) directly illuminates the imaging area (Ai) of the document placed on the contact glass (205), or the reflector mounted on the first traveling body ( 206) to reflect the imaging area (Ai) of the document.
  • Fig. 2 shows the illuminance distribution (Di) of the illumination light (204) in the vicinity of the imaging region (Ai).
  • the illumination light that illuminates the imaging area (Ai) by (206) is less than 1% of the amount of light generated in the cold-cathode tube illumination lamp (201), and is imaged by the illumination lamp (201) and reflector (207).
  • the efficiency of illuminating area (Ai) is very low.
  • the length of the imaging area (Ai) in the sub-scanning direction (Sy) is about 0.1 mm wide when using a 1-line CCD. When a 3-line CCD is used to read a color document, it is about 1 mm. Nevertheless, the illuminance distribution (Di) of the illumination light (204) in the sub-scanning direction (Sy) spreads over a wide range of several tens of mm centering on the imaging area (Ai).
  • FIG. 3 is a diagram for explaining another problem relating to illumination of a document in the image reading apparatus.
  • Fig. 3 when reading a book document (302) placed on the contact glass (301), the illuminance by the illumination light (303) directly illuminated from the illumination lamp is less than the illuminance by the reflected light from the reflector. Because it is several times higher, the reading position of the central part (304) of the book original (302) is insufficient in illuminance, and the central part (304) of the book original (302) is read as a black image. (Ad) may occur.
  • FIG. 4 is a diagram illustrating a light source composed of a plurality of LEDs and illumination by the light source.
  • FIG. 4 (a) is a diagram showing a single LED chip constituting the light source.
  • FIG. 4 (b) is a diagram for explaining the configuration of a light source composed of a plurality of LEDs.
  • FIG. 4 (c) is a diagram illustrating the illuminance distribution in the imaging region (Ai) illuminated by a light source composed of a plurality of LEDs.
  • an LED chip cut into a rectangle having a longitudinal direction (VI) and a lateral direction (Vs) is used.
  • a plurality of LED chips are aligned in the longitudinal direction (VI) of the LED chip as shown in FIG. 4 (a) to form a light source.
  • the light source is such that the direction in which the plurality of LEDs are aligned (longitudinal direction of the plurality of LEDs) is the main scanning direction (Sx) of the one-dimensional image sensor, and the short direction of the plurality of LEDs is
  • the one-dimensional imaging device is arranged so as to be in the sub-scanning direction (Sy).
  • the illumination target area (Ai) is illuminated using a light source composed of a plurality of LEDs arranged in this way.
  • the difference in the amount of light emission between the individual LEDs directly causes the illuminance unevenness of the illumination light by the light source.
  • shading correction is known as a technique for correcting slight illuminance unevenness.
  • the entire white part is scanned once in the main scanning direction (Sx), and the brightness distribution of the actually scanned document is electrically measured based on the brightness distribution in the scanned all white part. It can be corrected.
  • the LED luminous efficiency will vary more than twice. As shown in Fig.
  • the signal for the part illuminated with lower illuminance becomes a signal containing magnitude noise, which degrades the quality of the read signal.
  • selecting multiple LEDs with little or no variation in luminous efficiency will greatly reduce the yield of light sources composed of multiple LEDs, resulting in several times the cost increase. .
  • Patent Document 1 JP 2005-204272 A
  • Patent Document 2 JP-A-2005-242263
  • a first object of the present invention is to provide a document illumination method capable of illuminating a document with higher efficiency with light emitted from a light source.
  • a second object of the present invention is to provide a document illuminating device capable of illuminating a document with higher efficiency by light emitted from a light source.
  • a third object of the present invention is to provide an image reading apparatus that reads an image of a document illuminated by a document illumination device capable of illuminating the document with light emitted from a light source with higher efficiency. That is. Means for solving the problem
  • a first aspect of the present invention is a document illumination method for illuminating a document with light emitted from a light source, wherein light emitted from a plurality of light sources arranged at least in a first direction is superimposed. Illuminating the original with the superimposed light, and the light flux emitted from the plurality of light sources in the first direction with a distance between adjacent light sources in the plurality of light sources.
  • An original illumination method including diffusing twice or more.
  • a second aspect of the present invention is a document illumination device that illuminates a document with light emitted from a light source, and a plurality of light sources arranged in at least a first direction, and the plurality of light sources emitted from the plurality of light sources. And illuminating the original with the superimposed light, and causing the light flux emitted from the plurality of light sources to emit light beams adjacent to each other in the plurality of light sources in the first direction.
  • An original illuminating device including an optical system for diffusing at least twice the distance between the two.
  • a third aspect of the present invention includes an original illuminating apparatus that illuminates an original with light emitted from a light source, and an image reading apparatus that reads an image of the original illuminated by the original illuminating apparatus.
  • the illumination device superimposes a plurality of light sources arranged in at least a first direction and light emitted from the plurality of light sources to illuminate a document with the superimposed light, and the plurality of light sources
  • An image reading apparatus comprising: an optical system for diffusing a light beam emitted from a light source in the first direction to at least twice an interval between adjacent light sources in the plurality of light sources. It is.
  • a fourth aspect of the present invention provides a plurality of light sources arranged in at least a first direction, and superimposes light emitted from the plurality of light sources, and illuminates a document with the superimposed light.
  • an original illuminating apparatus including an illumination optical system that diffuses the light flux of light emitted from the plurality of light sources in the first direction more than a distance between adjacent light sources in the plurality of light sources,
  • An image of the original including an imaging optical system that forms an image scattered or reflected from the original illuminated by the original illuminating device, and an imaging element that images the light imaged by the imaging optical system
  • the plurality of light sources has an illuminance distribution characteristic of light illuminating the original on the original opposite to a brightness distribution characteristic of an image formed on the image sensor by the imaging optical system. Is arranged to be This is an image reading apparatus.
  • the first aspect of the present invention it is possible to provide a document illumination method capable of illuminating a document with higher efficiency by light emitted from a light source.
  • the second aspect of the present invention it is possible to provide a document illumination device capable of illuminating a document with higher efficiency by light emitted from a light source.
  • the image reading device reads an image of the original illuminated by the original illumination device capable of illuminating the original with higher efficiency by the light emitted from the light source. Can be provided.
  • the image reading device reads an image of the original illuminated by the original illumination device capable of illuminating the original with higher efficiency by the light emitted from the light source. Can be provided.
  • FIGS. 1A and 1B are a schematic view of a general image reading apparatus and a cross-sectional view of the image reading apparatus in the sub-scanning direction, respectively.
  • FIG. 2 is a diagram for explaining a problem relating to document illumination in the image reading apparatus.
  • FIG. 3 is a diagram for explaining another problem relating to illumination of a document in the image reading apparatus.
  • FIG. 4 is a diagram illustrating a light source composed of a plurality of LEDs and illumination by the light source.
  • FIG. 5 is a diagram for explaining an example of an illumination method and an illumination device according to the first embodiment of the present invention.
  • FIG. 6 is a diagram illustrating an example of an image reading apparatus according to a second embodiment of the present invention.
  • FIG. 7 is a diagram illustrating an example of an image reading apparatus according to a third embodiment of the present invention.
  • FIG. 8 is a diagram for explaining a modification of the image reading apparatus according to the third embodiment of the present invention.
  • FIG. 9 is a diagram illustrating a means for converting a light beam diffusing from an LED into parallel light using a rotating parabolic mirror.
  • FIG. 10 is a diagram for explaining means for converting a light beam diffused from an LED into parallel light using a convex lens.
  • FIG. 11 is a diagram for explaining one example of a lighting device according to a fourth embodiment of the present invention.
  • FIG. 12 is a diagram for explaining another example of a lighting device according to the fourth embodiment of the present invention.
  • FIG. 13 is a diagram for explaining one example of an illumination device and an image reading device according to a fourth embodiment of the present invention.
  • FIG. 14 is a diagram for explaining another example of the illumination device and the image reading device according to the fourth embodiment of the present invention.
  • FIG. 16 is a diagram illustrating an example of an illumination method and an image reading apparatus according to a sixth embodiment of the present invention.
  • FIG. 19 is a diagram illustrating an example of a lighting device according to an eighth embodiment of the present invention.
  • FIG. 20 is a diagram illustrating an example of an image reading apparatus according to a ninth embodiment of the present invention.
  • FIG. 21 is a diagram illustrating an example of an image reading apparatus according to a tenth embodiment of the present invention.
  • FIG. 22 is a diagram for explaining the relationship between the illuminance distribution in the imaging region and the relative brightness of the reduction optical system on the CCD in the image reading apparatus using the reduction optical system.
  • FIG. 23 is a diagram for explaining a method of determining the arrangement intervals of a plurality of light sources that illuminate an imaging region so that the relative brightness of an image formed on a two-dimensional CCD is constant.
  • FIG. 24 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a two-dimensional CCD is constant.
  • FIG.25 A specific example of the relative brightness of an image that is imaged on a one-dimensional CCD by an imaging lens in an imaging target area illuminated at a constant illuminance, and the phase of the image that is imaged on the one-dimensional CCD. It is a figure which shows the specific example of target illuminance distribution (request
  • FIG. 26 A diagram showing a result of simulation toward a target relative illuminance for illuminating an illumination target area (imaging target area).
  • imaging target area It is a conceptual diagram for realizing an illumination device that matches the illuminance distribution of the light that illuminates the imaging region with the 1 / cos 4 ⁇ characteristic by adjusting the interval between the plurality of light sources.
  • FIG. 28] is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a two-dimensional CCD is constant.
  • FIG. 29 is a diagram showing a simulation result of relative illuminance in the twelfth practical example of the present invention.
  • Fig. 31 is a diagram for explaining an example of a method for changing the radiation characteristics of the light that is also emitted by the light source.
  • Gaku 32] illuminates the imaging area so that the relative illuminance of the image formed on the three-dimensional CCD is constant. It is a figure explaining another example of arrangement
  • FIG. 35 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate an imaging target region so that the relative brightness of an image formed on a three-dimensional CCD is constant.
  • the illuminance distribution of the light that illuminates the imaging area is adjusted to 1 / cos 4 ⁇ both by adjusting the power of each of the multiple light sources, adjusting the distance to the imaging area, and adjusting the radiation characteristics of the light emitted by the multiple light source forces. It is a conceptual diagram for implement
  • FIG. 38 is a diagram showing a simulation result on the difference between the relative illuminance and the target illuminance distribution in the sixteenth actual example of the invention.
  • FIG.39 By adjusting the angle of the illumination optical axis of light that is also emitted from multiple light sources, an illuminator that matches the illuminance distribution of the light that illuminates the imaging area with the 1 / cos 4 ⁇ characteristic is realized. It is a conceptual diagram for.
  • FIG. 40 is a diagram for explaining the formation of a virtual light source from a light source using a concave cylinder lens.
  • FIG. 41 is a diagram for explaining an optical component that can be used in the embodiments and examples of the present invention.
  • FIG. 42 is a diagram illustrating an optical component that can be used in the embodiment and examples of the present invention.
  • Electrode 22 ... Lead wire 23 ... Transparent resin 24 ... Food lens 25 ... Base 31 ... Photoreceptor, 32 ... Paper feed roller, 33 ... Sheet original, Sx ... Main scanning direction, Sy ... Sub-operation direction, ⁇ ... Illumination optical axis, AxR ... Reading optical axis, Ai ... Imaging area, Illumination area, Illumination target area, Di ... Illuminance distribution VI ⁇ ⁇ ⁇ longitudinally, Vs ... lateral direction, VLS ... virtual source, the virtual light source.
  • Embodiments of the present invention relate to a document surface illumination method, a (document) illumination device, and an image reading device using the same.
  • Embodiments of the present invention include, for example, an illumination method and an illumination device for illuminating a document surface of a copying machine or a facsimile, a solid-state imaging device mounted on a digital PPC (common paper copying machine), etc.
  • the present invention relates to an image reading apparatus (such as a film scanner and a non-day scanner) equipped with an imaging lens and an illumination device, and an illumination device for the image reading device.
  • scattered light from a document surface illuminated by light from a light source is imaged on a photoconductor or an image sensor by an imaging lens to form an image on an image on the document surface.
  • a one-dimensional image is formed at the target position, and the image formation target position on the document surface is sequentially moved in a direction (sub-scanning direction) perpendicular to the direction along the one-dimensional image (main scanning direction).
  • a document surface illumination method for an image forming apparatus that forms a two-dimensional image of a surface image
  • a plurality of light sources are arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction). Illuminating the document surface for an image forming apparatus, wherein the light beam emitted from the light source is diffused in a direction along the one-dimensional image of the document surface in a range of at least twice the interval between adjacent light sources. Is the method.
  • the scattered light from the document surface illuminated by the light from the light source is imaged on the photosensitive member or the image sensor by the imaging lens, thereby forming an image on the image on the document surface.
  • a one-dimensional image is formed at the target position, and the image formation target position on the document surface is sequentially moved in a direction (sub-scanning direction) perpendicular to the direction along the one-dimensional image (main scanning direction).
  • a document surface illumination method for an image forming apparatus that forms a two-dimensional image of a surface image, a plurality of light sources are arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction).
  • an original surface illumination method for an image forming apparatus is schematically focusing.
  • the light emitting means, the imaging means for forming an image on the image pickup device from the scattered light from the original surface illuminated by the light generated from the light emitting means, and the image on the original surface are used.
  • an illumination device for an image reading apparatus that reads an image, the light emitted from a plurality of light emitting means and a plurality of light emitting means arranged at least in a direction corresponding to a direction along the one-dimensional image (main scanning direction).
  • Light diffusion that diffuses the light flux in a direction along the one-dimensional image of the document surface in a range that is at least twice the interval between adjacent light-emitting means It is an illuminating device for image reading apparatuses characterized by having a means.
  • a pair of reflections is provided so as to sandwich a plurality of light emitting means arranged at least in a direction corresponding to a direction along the one-dimensional image (main scanning direction).
  • Mirrors are arranged in parallel.
  • the light diffusion means is a cylinder lens (or
  • the position of the light source in each of the plurality of light emitting units is arranged so as to correspond to each of the plurality of light emitting units.
  • an ellipsoidal mirror in which the position of the light source in each of the plurality of light emitting means is the position of one focal point corresponds to each of the plurality of light emitting means. Be placed.
  • a convex lens corresponding to each of the plurality of light emitting means is arranged.
  • At least a part of light beams emitted from a plurality of light sources are perpendicular to a direction along the one-dimensional image of the document surface (main scanning direction).
  • light focusing means for roughly focusing is arranged.
  • the light emitting means is a light emitting diode (LE).
  • the scattered light from the original surface illuminated by the light from the light source is imaged on the image sensor by the imaging lens, and the image reading position in the image on the original surface is obtained.
  • the light flux emitted from a plurality of light sources is diffused in a range along the one-dimensional image of the document surface in a range more than twice the interval between adjacent light sources, and To draft surface
  • An image reading apparatus having a plurality of lenses (illumination lenses) to be superimposed
  • the image reading apparatus for reading a two-dimensional image in the image on the document surface includes the illumination device according to the third embodiment of the present invention.
  • the scattered light from the original surface illuminated by the light from the light source is imaged on the image sensor by the imaging lens, and the image formation target position in the image on the original surface
  • the one-dimensional image is read and the image formation target position on the document surface is sequentially moved in the direction (sub-scanning direction) perpendicular to the direction of reading the one-dimensional image (main scanning direction) and the reading of the one-dimensional image is repeated.
  • the image reading apparatus that reads a two-dimensional image in the image on the document surface, a plurality of light sources arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction), and a plurality of light sources
  • the light beams emitted from a plurality of light sources are arranged so as to correspond to each other in a direction along the one-dimensional image of the document surface, and are diffused to a range that is equal to or larger than the interval between adjacent light sources.
  • the plurality of light sources has an illuminance distribution characteristic of light that illuminates the document surface at the document formation target position.
  • the image reading apparatus is arranged so as to be approximately opposite to a lightness distribution characteristic of an image formed on an imaging element by an imaging lens.
  • the interval between the plurality of light sources is set to be an image.
  • the distribution characteristic of the illuminance of the light that illuminates the document surface at the image formation target position is set so that it is roughly opposite to the lightness distribution characteristic of the image formed by the imaging lens on the imaging element.
  • an image reading apparatus according to a sixth embodiment of the present invention or a sixth embodiment of the present invention.
  • the distance from the document surface to the plurality of light sources is such that the distribution characteristic of the illuminance of the light that illuminates the document surface at the image formation target position is the image sensor. Is set so as to be approximately opposite to the brightness distribution characteristic of the image formed by the imaging lens.
  • a light flux emitted from a plurality of light sources The divergence angle is such that the illuminance distribution characteristic of the light that illuminates the original surface at the image formation target position is roughly opposite to the lightness distribution characteristic of the image formed by the imaging lens on the image sensor. To be set.
  • the directions of the optical axes of the plurality of light sources depend on the image forming pair.
  • the distribution characteristic of the illuminance of the light that illuminates the document surface on the document surface at the elephant position is set so as to be approximately opposite to the distribution characteristic of the brightness of the image formed on the image sensor by the imaging lens.
  • the “illuminating device for the image reading device” includes a plurality of light sources arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction) used in the image reading device. And an illuminating device that illuminates the document surface with light from these multiple light sources.
  • the interval between a plurality of light sources, the document surface Combination of at least two of force, distance to a plurality of light sources, divergence angle of light beams emitted from the plurality of light sources, and direction of optical axes of the plurality of light sources (for example, a plurality from the document surface)
  • the distance to the light source and the divergence angle of the luminous flux of the emitted light and the distribution characteristics of the illuminance of the light that illuminates the document surface at the image formation target position. May be set so as to be roughly opposite to the lightness distribution characteristic of the image formed by.
  • the irradiated surface is a surface having a certain area.
  • a plurality of light sources are arranged in a direction corresponding to at least a direction along the one-dimensional image (main scanning direction), and emitted from the plurality of light sources.
  • a wider area on the document surface using multiple light sources by diffusing the emitted light flux in the direction along the one-dimensional image of the document surface to a range that is at least twice the interval between adjacent light sources.
  • a light beam emitted from a plurality of light sources is divided into a direction (sub scan direction) perpendicular to the direction along the one-dimensional image of the document surface (main scanning direction).
  • a direction perpendicular to the direction along the one-dimensional image of the document surface (main scanning direction).
  • the reflecting mirror, the cylinder lens (or cylindrical lens), the parabolic mirror, the elliptical mirror, and the convex lens are plastic molded. Since it is possible to obtain the force S by means, the cost of the illumination device or the image reading device can be reduced.
  • the light source when a light emitting diode (LED) is used as a light source, the light source can be driven by a low-voltage DC power supply. Can be easily provided. As a result, the cost of the illumination device or the image reading device can be reduced.
  • LED light emitting diode
  • the plurality of light sources has an illuminance distribution characteristic of light that illuminates the document surface at the image forming target position so that the imaging element has an imaging lens. Since it is arranged so as to be roughly opposite to the brightness distribution characteristic of the image formed by the image, it is blocked or discarded without illuminating the original surface of the light emitted from the plurality of light sources. It is possible to reduce or eliminate the amount of light generated and to make the brightness distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency with the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • the interval between the plurality of light sources is such that the distribution characteristic of the illuminance distribution of the light that illuminates the document surface on the document surface at the image formation target position is imaged. Since it is set so as to be roughly opposite to the lightness distribution characteristic of the image formed by the imaging lens on the element, it is blocked without illuminating the document surface among the light emitted from a plurality of light sources or It is possible to reduce or eliminate the amount of light thrown away and to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • the distance from the document surface to the plurality of light sources is the distribution characteristic of the illuminance of light that illuminates the document surface on the document surface at the image formation target position. Since it is set to be roughly opposite to the brightness distribution characteristics of the image formed by the imaging lens on the image sensor, the light emitted from multiple light sources is blocked without illuminating the document surface. It is possible to reduce or eliminate the amount of light emitted or discarded and to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency with the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • the divergence angle of light beams emitted from a plurality of light sources is the illuminance of light that illuminates the document surface at the image formation target position. Since the distribution characteristics are set so as to be roughly opposite to the distribution characteristics of the brightness of the image formed by the imaging lens on the image sensor, the original surface of the light emitted from the plurality of light sources is illuminated. It is possible to reduce or eliminate the amount of light that is interrupted or discarded without making it possible to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source. As a result, the energy required to illuminate the original surface can be reduced (energy saving).
  • the direction of the optical axis of the plurality of light sources is determined by the distribution characteristics of the illuminance of the light that illuminates the document surface at the image formation target position. Since it is set so as to be roughly opposite to the brightness distribution characteristic of the image formed on the element by the imaging lens, it is blocked without illuminating the document surface among the light emitted from the plurality of light sources or It is possible to reduce or eliminate the amount of light thrown away and to make the illuminance distribution of the image formed by the imaging lens in the image sensor more uniform. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • Set the illuminance distribution characteristics of the light that illuminates the document surface at the target position to be roughly opposite to the brightness distribution characteristics of the image formed by the imaging lens on the imaging element.
  • the amount of light that is blocked or discarded without illuminating the document surface among the light emitted from a plurality of light sources is reduced or eliminated, and the image formed by the imaging lens in the image sensor is reduced. Make the illumination distribution more uniform It can become. As a result, it is possible to illuminate the document with higher efficiency by the light emitted from the light source, and it is possible to reduce the energy required to illuminate the document surface (energy saving).
  • the illumination method and the illumination device according to the embodiment of the present invention are designed to form a latent image on a photoconductor by directly projecting an image on a document surface onto the photoconductor, and developing the latent image with black toner or color toner.
  • an illumination method and an illumination device used in an image reading apparatus generally called a digital printer or a scanner will be described. I will do it.
  • Example 1
  • FIG. 5 is a diagram for explaining an example of an illumination method and an illumination apparatus according to the first embodiment of the present invention.
  • FIG. 5 (a) is a top view of the example of the lighting device according to the first embodiment of the present invention
  • FIG. 5 (b) is a front view of the example of the lighting device according to the first embodiment of the present invention. is there.
  • FIG. 5 (c) shows the illuminance distribution in the main scanning direction (Sx) on the illumination target surface (imaging area) (Ai) obtained by the example of the illumination method according to the first embodiment of the present invention.
  • FIG. 5 (d) is a diagram showing the illuminance distribution in the sub-scanning direction on the illumination target surface (imaging area) (Ai) obtained by the example of the illumination method according to the first embodiment of the present invention. is there.
  • the illumination device according to the first embodiment of the present invention as shown in FIGS. 5 (a) and (b) is an illumination lamp and reflector in the conventional illumination device shown in FIGS. 1 (a) and (b). Corresponding to
  • the illumination device includes a plurality of LEDs (1), a plurality of rotary parabolic mirrors (2a), and an illumination lens. (3) It has a focusing lens (4a) and side mirror A (5a) and side mirror B (5b).
  • Each of the plurality of LEDs (1) is a light emitting diode chip and is used as a light source.
  • n LEDs (l) (Ll to Ln) are arranged at equal intervals in the main scanning direction (Sx).
  • Each of the plurality of rotating parabolic mirrors (2a) is arranged corresponding to the plurality of LEDs (1), and the light emitting surface of the LED (1) is located at the focal position of the rotating parabolic mirror (2a). By arranging the LED power, most of the diffused light is converted into parallel light.
  • the plurality of rotary paraboloid mirrors (2a) are used as a first focusing means for focusing the luminous flux diffusing at an angle of 180 ° from the light emitting surface of the LED (1) to the front side of the LED (1).
  • the illumination lens (3) is a cylinder lens array in the illumination device of the first embodiment of the present invention.
  • the illumination lens (3) diffuses the parallel light beam emitted from the rotary paraboloid mirror (2a) in the main scanning direction (Sx) and is diffused by the illumination lens (3).
  • the surface (Ai) (refers to the same part as the imaging region, but when the illumination device is described, the imaging region is referred to as an illumination target surface or an illumination target region) is illuminated.
  • the individual lenses constituting the cylinder lens array of the illumination lens (3) are completely or substantially the same cylinder lens.
  • f is the focal length of each cylinder lens
  • m is the width of each cylinder lens in the cylinder lens array direction (main scanning direction (Sx)).
  • each cylinder lens is equal to the interval between adjacent LEDs (l) in the plurality of LEDs (l).
  • illumination is performed by light transmitted through the cylinder lens in the cylinder lens arrangement direction (main scanning direction (Sx)).
  • the width m of each cylinder lens that is, the cylinder lens with respect to the interval between adjacent LEDs (1) in the plurality of LEDs (1).
  • the ratio (M / m) of the illumination range M on the illumination target surface (imaging area) (Ai) illuminated by the light that has passed through is more than twice.
  • the cylinder lens is equivalent to a plane parallel plate, and therefore, a paraboloid mirror.
  • the width of the cylinder lens array in the main scanning direction (Sx) may also be K.
  • the width of the cylinder lens in the main scanning direction (Sx) is preferably completely or substantially the same as the width of the paraboloid mirror (2a) in the main scanning direction (Sx). That is,
  • the force S is preferable, where n is the number of cylinder lenses constituting the cylinder lens array.
  • the focusing lens (4a) is a single cylinder lens that focuses the light transmitted through the illumination lens (3) onto the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy). It is provided as follows. That is, the parallel light emitted from the rotating parabolic mirror (2a) is transmitted in the sub-scanning direction (Sy) In this case, the light is not diffused by the illumination lens (3), but is sharply focused on the illumination target surface (imaging area) (Ai) by the focusing lens (4). Since the focusing lens (4) is equivalent to a plane-parallel plate in the main scanning direction (Sx), the light diffused by the illumination lens (3) is not focused by the focusing lens (4). , Diffuse as it is. The collecting lens (4) can be easily substituted with a parabolic mirror having the same function as the focusing lens.
  • the focusing lens (4) transmits light transmitted through the illumination lens (3), which is not necessarily required, in the illumination device of the first embodiment of the present invention.
  • it may be applied to the illumination target surface (imaging area) (Ai) as parallel light.
  • the focusing lens (4) may be arranged on the illumination lens (3) side or on the illumination target surface (imaging region) (Ai) side position.
  • the focusing lens (4) can be formed integrally with the illumination lens (3). In this case, the number of parts used for the lighting device can be reduced by using plastic molding means.
  • the side mirror A (5a) and the side mirror B (5b) are mirrors arranged on both sides of the cylinder lens array of the illumination lens (3).
  • the side mirror A (5a) and the side mirror B (5b) are provided to irradiate the illumination target surface (imaging region) (Ai) with higher efficiency with the light emitted from the LED (l).
  • the light emitted from the three LEDs (l) (Ll, L2, and L3) is reflected by the side mirror A (5a) to the illumination target surface (imaging area) (Ai).
  • the light emitted from the three LEDs (1) (Ln-2, Ln-1 and Ln) is reflected by the side mirror B (5b) to the illumination target surface (imaging area) (Ai).
  • side mirror A (5a) and side mirror B (5 b) have their six LEDs (1) force as if they were also placed outside the lighting device. Since the light from the six LEDs (1) is reflected, the edge of the illumination target surface (imaging area) (Ai) is uniform as well as the center of the illumination target surface (imaging area) (Ai). Illuminance distribution is obtained. (Note that it is ideal to provide a side mirror to the illumination target surface (imaging area) (Ai) for the cylinder lens array force. In an actual image reading device, avoid contact glass as a document table.
  • the illuminance at the end of the illumination target surface (imaging area) (Ai) is slightly lower than the illuminance at the center of the illumination target surface (imaging area) (Ai). Accordingly, when the side mirror A (5a) and side mirror B (5b) are provided, it is necessary to increase the overall width of the illuminating device in the main scanning direction (Sx). The amount of variation in the overall width of the lighting device is very small compared to the amount of variation in the overall width of the lighting device when the side mirror is not used. )
  • the light emitted from (L4) is reflected by the rotating parabolic mirror (2a) corresponding to L4 and is emitted as substantially parallel light.
  • the light emitted from the rotary parabolic mirror (2a) corresponding to L4 is incident on the cylinder lens constituting the illumination lens (3) corresponding to L4.
  • the light that has passed through the cylinder lens is diffused regardless of the presence of the focusing lens (4) at a distance that exceeds the focal length f of the force cylinder lens that is once focused at the focal length f of the cylinder lens.
  • the width of the light beam emitted from the L4 of the LED (1) is equal to the width m of the cylinder lens, that is, the adjacent LEDs (1).
  • the ratio of the luminous flux width M on the illumination target surface (imaging area) (Ai) to the size of the LED (1) interval is more than twice. In Fig. 5, Q is about 6.5.
  • the illuminance distribution on the illumination target surface (imaging region) (Ai) due to only the light emitted from L4 of the LED (1) is as shown by the bold line in FIG. 5 (c). Things (Each-Di). That is, the illuminance on the axis (optical axis) passing through the center of the rotating paraboloid mirror (2a) corresponding to L4 and L4 of LED (1) is a peak, and from L4 as it goes away from the optical axis. The illuminance due to the emitted light decreases.
  • the illuminance distribution on the illumination target surface (imaging area) (Ai) due to only the light emitted from L4 of the LED (1) depends on the position on the illumination target surface (imaging area) (Ai).
  • the illuminance distribution on the illumination target surface (imaging area) (Ai) due to only the light emitted from L4 of the LED (1) depends on the position on the illumination target surface (imaging area) (Ai).
  • the light on the optical axis of L4 of LED (1) is the smaller amount of light emitted from L1 of LED (1), LED (1 ) L2 of light emitted from L2, and a larger amount of light emitted from L3 of LED (2).
  • the light on the optical axis of L4 of LED (1) is the same as the amount of light emitted from L3 of LED (l).
  • the amount of light emitted from L5 of LED (1), the amount of light emitted from L6 of LED (1), and the amount of light emitted from L2 of LED (1), and The amount of light emitted from L1 of LED (1) is included in the same amount as the amount of light emitted from L1 of LED (1).
  • the light emitted from L1 to L7 of LED (1) is superimposed on the illumination target surface (imaging area) (Ai) and Illuminate the illumination target surface (imaging area) (Ai).
  • an arbitrary point on the illumination target surface (imaging region) (Ai) is the number of numbers obtained by rounding down the numbers after the decimal point of the Q value described above.
  • the LED is illuminated with the light emitted from the LED (or 6 or 7 in Fig. 5) of the number obtained by rounding up the number after the decimal point of the LED or Q value described above.
  • the illuminance distribution on the illumination target surface (imaging region) (Ai) becomes more uniform and flat (shows the concept of “Total-Di”).
  • the light diffused from each of the plurality of LEDs (1) It is converted into almost parallel light by the rotating parabolic mirror (2a) corresponding to the LED (1), and passes through the illumination lens (3) as parallel light.
  • the illumination target surface (imaging area) (Ai) is illuminated as it is.
  • the illuminance distribution on the illumination target surface (imaging area) is the illuminance distribution due to the individual LEDs (1) as shown by the solid line in FIG.
  • the focusing lens (4a) when a sharp illumination distribution on the illumination target surface (imaging area) (Ai) is required in the sub-scanning direction (Sy), Use the focusing lens (4a).
  • the illumination device does not include the focusing lens (4a)
  • the illuminance distribution on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) is shown by the two-dot chain line in FIG.
  • an intermediate illuminance distribution between a relatively sharp illuminance distribution and a relatively broad illuminance distribution is necessary on the illumination target surface (imaging area) (Ai).
  • the focal length of the focusing lens (4) is set so that the focal point of the focusing lens is away from the position of the illumination target surface (imaging area) (Ai).
  • An illuminance distribution having an arbitrary width can be obtained with (A i). In this way, the illuminance distribution on the illumination target surface (imaging region) (Ai) is maintained substantially constant in the main scanning direction (Sx), and the illumination target surface (imaging region) is observed in the secondary scanning direction (Sy).
  • the illuminance distribution on (Ai) can be arbitrarily set to a shear or broad illuminance distribution.
  • FIG. 6 is a diagram for explaining an example of an image reading apparatus according to the second embodiment of the present invention.
  • FIG. 6 (a) shows a second embodiment of the present invention using the lighting device according to the first embodiment of the present invention.
  • FIG. 6B is a front view of the image reading apparatus according to the second embodiment of the present invention using the illumination apparatus according to the first embodiment of the present invention.
  • FIG. 6 (a) a turning mirror (12) is depicted in addition to the illumination device according to the first embodiment of the present invention as shown in FIG.
  • FIG. 6 (b) when an illuminating device that does not bend the optical axis of the illuminating device is disposed, the optical axis of the reading system that is the optical path of the reflected light from the imaging region (Ai)
  • the entire optical axis of the illuminating device is tilted from the reading optical axis (A xR). is there.
  • the illumination optical axis (Axl) can be bent using the folding mirror (6). In this way, the size of the image reading device in the direction perpendicular to the contact glass (13) can be reduced by arranging the illumination device in parallel to the surface of the contact glass (13). .
  • the illumination device may or may not include the focusing lens (4a) depending on the target illuminance distribution in the imaging region (Ai) in the sub-scanning direction (Sy).
  • FIG. 6 (c) is a top view of the image reading apparatus according to the second embodiment of the present invention using a modification of the illumination apparatus according to the first embodiment of the present invention
  • FIG. FIG. 7 is a front view of an image reading apparatus according to a second embodiment of the present invention using a modification of the illumination apparatus according to the first embodiment of the present invention.
  • the focusing mirror (4b) is a parabolic mirror having a focal point in the imaging area (Ai) in the sub-scanning direction (Sy), and a reflection having no focusing function in the main scanning direction (Sx). It is a mirror that is a surface. Further, since the focusing mirror (4b) can have the function of the folding mirror (12) shown in FIGS. 6 (a) and 6 (b), the number of components of the lighting device can be reduced and the contact glass (13 It is possible to reduce the size of the image reading device in the direction perpendicular to). Note that the bending direction of the reading optical axis (AxR) may be any of the left and right directions in FIG.
  • the lighting device is designed so that the luminous fluxes emitted from 10 or more LEDs overlap, the illuminance unevenness in the entire imaging area (Ai) in the main scanning direction (Sx) can be reduced. It can be reduced to less than 10%.
  • electrically correcting the illuminance unevenness in the imaging area (Ai) it is possible to reduce the noise of the image signal even in a place where the illuminance is low in the imaging area (Ai), thereby improving the quality of the image signal. It becomes possible.
  • FIG. 7 is a diagram for explaining an example of an image reading apparatus according to the third embodiment of the present invention. Fig 7
  • the folding mirror B (6b) on the front side of the optical axis (AxR) Reflected to the imaging area (Ai) by the folding mirror B (6b) on the front side of the optical axis (AxR) (Note that the light beam on the direction mirror (12) side of the illumination optical axis (Axl) is read light. Since it folds in front of the axis (AxR), the size of the folding mirror A (6a) can be reduced, and the entire illuminator should be closer to the reading optical axis (AxR) side. I can do it. ).
  • the focal length of the focusing lens (4a) is common to all the light beams transmitted through the focusing lens (4a), the arrangement of the folding mirrors A and B (6a, 6b) is determined by the focusing lens (4a).
  • the light is reflected to the imaging region (Ai) by the folding mirror A (6a). Furthermore, the light flux on the contact glass (13) side of the illumination optical axis (Axl) is focused on the rear side (FB) of the imaging area (Ai), and the direction of the mirror is changed more than the illumination optical axis (Axl) (12 ) Side beam is focused on the front side (FA) of the imaging area (Ai). In this case, the central part of the document surface of the book document is irradiated with the light flux on the contact glass (13) side from the illumination optical axis (Axl), and the deflecting mirror (12) from the illumination optical axis (Axl).
  • the light beam on the side can be diffused without being focused on the original surface of the book original, and can be irradiated onto the book original. As a result, it is possible to irradiate the central portion of the book document with a good balance of light and to prevent or reduce reading of the central portion of the book document as a black image.
  • the light beam on the (12) side is reflected to the imaging area (Ai) by the focusing mirror A (4bl) on the rear side of the reading optical axis (AxR).
  • the focusing mirror A (4bl) and the focusing mirror B (4b 2) are parallel planes in the main scanning direction, and appear to be paraboloids having a focal point in the imaging region (A i) in the sub-scanning direction. It is a mirror.
  • the size of the focusing mirror A (4bl) is reduced because there is no need to reflect the light beam on the direction of the mirror (12) with respect to the illumination optical axis (Axl) by the focusing mirror A (4bl).
  • the power to do S In Fig.
  • both the luminous flux on the contact glass (13) side from the illumination optical axis (Axl) and the luminous flux on the deflecting mirror (12) side from the illumination optical axis (Axl) are both captured in the imaging region (Ai).
  • focusing is performed before and after the imaging area (Ai) independently.
  • the illuminance distribution in the imaging region (Ai) by the substantially parallel light beam on the contact glass (13) side from the illumination optical axis (Axl) shows a broad distribution
  • the illuminance distribution in the imaging area (Ai) due to the light flux on the direction of the deflecting mirror (12) with respect to the optical axis (Axl) shows a sharp distribution.
  • the example of the image reading apparatus as shown in FIGS. 7E and 7F is an example of an image reading apparatus that uses neither a focusing lens nor a focusing mirror.
  • the light beam on the contact glass (13) side from the illumination optical axis (Axl) out of the substantially parallel light beam transmitted through the illumination lens is read light.
  • Reflected to the imaging area (Ai) behind the axis (AxR), and the luminous flux on the deflecting mirror (12) side from the illumination optical axis (Axl) is reflected to the imaging area (AxR) before the reading optical axis (AxR). Reflect to Ai).
  • the illumination light out of the substantially parallel light beams transmitted through the illumination lens.
  • the light beam on the contact glass (13) side of the axis (Axl) is reflected to the imaging area (Ai) on the front side of the reading optical axis (AxR), and the deflecting mirror (12) side of the illumination optical axis (Axl) side Are reflected to the imaging area (Ai) behind the reading optical axis (AxR).
  • the image reading apparatus using the focusing lens or the focusing mirror the light use efficiency of the illuminating device is reduced, but the illuminance distribution in the imaging area (Ai) is broad, and the book document Reading the central portion as a black image can be prevented or reduced more effectively.
  • FIG. 7 shows an example of the arrangement of the focusing lens, the folding mirror, and the focusing mirror in the image reading apparatus.
  • the arrangement of the focusing lens, the folding mirror, and the focusing mirror is arbitrary, and is shown in FIG. It is not limited to that.
  • the light beam is divided in half before and after the illumination optical axis (Axl).
  • the ratio of the light beam division is not limited to 5: 5, and imaging is performed. It is arbitrarily set according to the degree of focusing in the area (Ai) or the type of document, and may be 6: 4 or 3: 7, for example.
  • FIG. 8 is a diagram for explaining a modification of the image reading apparatus according to the third embodiment of the present invention.
  • FIG. 8 (a) is a diagram for explaining a first modification of the image reading apparatus according to the third embodiment of the present invention
  • FIG. 8 (b) is an image according to the third embodiment of the present invention.
  • FIG. 10 is a diagram illustrating a second modification of the reading device.
  • the illuminating device main body is arranged on the front side or the rear side with respect to the reading optical axis (AxR) to illuminate the imaging region (Ai).
  • the light flux is divided into two and the imaging area (Ai) is illuminated from both the front side and the rear side of the reading optical axis (AxR).
  • two illumination device bodies are arranged on both the front side and the rear side of the reading optical axis (AxR), and the two illumination device bodies are arranged.
  • the imaging area (Ai) is used to illuminate the imaging area (Ai) from both the front and rear forces of the reading optical axis (AxR).
  • the two light source bodies (Axl) including the focusing lens (4a) are not bent and the two optical axes (Axl) are not bent.
  • the main body of the illuminating device is arranged obliquely with respect to the reading optical axis (AxR). In this case, it is possible to reduce the size of the image reading device in the direction parallel to the surface of the contact glass (13). As shown by the two-dot difference line in Fig.
  • the illuminating device body is placed parallel to the surface of the contact glass (13) using the folding mirror (6). You can also place yourself. In this case, the size of the image reading device in the direction perpendicular to the surface of the contact glass (13) can be reduced.
  • the example of the image reading apparatus as shown in FIG. 8 may not include either one of the two illuminating device bodies or both the force focusing lens and the focusing mirror. Modifications in the example of the image reading apparatus as shown can be applied.
  • FIG. 9 is a diagram for explaining a means for converting a light beam diffusing from an LED into parallel light using a rotary parabolic mirror.
  • Figure 9 (a) is a front view of a light source including LEDs and a rotating parabolic mirror.
  • FIG. 9 (b) is a side view of a light source including an LED and a rotating parabolic mirror.
  • the X, y, and z axes are defined, and the LED is at the intersection of the x, y, and z axes.
  • the center of the light emitting surface of (1) is arranged.
  • the focal length of the parabolic mirror (2a) is f
  • the paraboloid of the parabolic mirror (2a) is the paraboloid of the parabolic mirror (2a)
  • [0117] is a paraboloid obtained by rotating the parabola represented by X around the X axis.
  • the center of the light emitting surface of the LED (1) is arranged at the focal position (Pf) of the paraboloid.
  • the light emitting surface of the LED (1) faces the rotary parabolic mirror (2a).
  • the LED (l) is connected to the two electrodes (21) via the lead wire (22) and embedded in the transparent resin (23). .
  • the outer periphery of the rotating parabolic mirror (2a) may be circular, but radiation from the light emitting surface of LED (1) in Fig. 9 (a).
  • the intensity of the rotating paraboloid mirror (2a) in the vicinity is lower than that in the vicinity of the X axis, so the main scanning direction (Sx) (eg, z direction) Increased density to place a rotating paraboloid (2a) in
  • the peripheral part of the rotating parabolic mirror (2a) in the main scanning direction (Sx) may be cut off (that is, when the rotating parabolic mirror (2a) is viewed from the side, the rotating parabolic mirror is (2a) has an oval shape).
  • the peripheral part of the rotary parabolic mirror (2a) in the sub-scanning direction (Sy) is You can cut it out! / (Ie, when the paraboloid mirror (2a) is viewed from the side, the paraboloid mirror (2a) has a square shape).
  • the light emitting surface of LED (1) has an area, so there is only one place where light is emitted at the focal position of the rotating paraboloid. All light emitted at other positions is from the focal position of the rotating paraboloid. It is off.
  • the light emission vectors emitted from the focal position of the rotary parabolic mirror (2a) are all parallel light.
  • the light emission vectors emitted from other locations are all reflected when reflected by the rotary parabolic mirror (2a). It will deviate from the parallel light. The deviation increases as the distance from the focal point of the parabolic mirror (2a) increases.
  • Fig. 9 (c) shows the light emitted from a light source including a rotating paraboloid mirror and LED as shown in Figs. 9 (a) and 9 (b) at a certain distance. It is a light distribution characteristic figure which shows the vector intensity of the light which passes a certain point of the vicinity of an axis
  • the horizontal axis in Fig. 9 (c) represents the angle (°) from the optical axis of the parabolic mirror, and the vertical axis in Fig. 9 (c) represents the strongest value of the intensity of the light vector passing through a certain point.
  • the component parallel to the optical axis (X-axis) of the parabolic mirror (X axis) is strongest (0 degree), but there is also a component with an angle. (The amount decreases as the angle increases. The angle that falls to 50% is called the half-width, and in this example is ⁇ 5 degrees.)
  • FIG. 10 is a diagram illustrating a means for converting a light beam diffusing from an LED into parallel light using a convex lens.
  • 10 (a) is a front view of a light source including an LED and a convex lens
  • FIG. 10 (b) is a side view of the light source including an LED and a convex lens.
  • the light source including the LED and the convex lens shown in Figs. 10 (a) and 10 (b) is called a cannonball type, and the LED (1) attached to the base 25 is a convex lens made of a resin material. It is covered with a hood lens (24) with a shape.
  • LED (l) is connected to the electrode (21) via the lead wire (22).
  • the center of the light emitting surface of the LED (1) is arranged at the focal position (Pf) of the hood lens (24) which is a convex lens.
  • the lens size of the hood lens (24) As shown in Fig. 10 (a), the angular force of light incident on the periphery of the convex lens shape is determined to be less than the critical angle ⁇ .
  • the outer periphery of the hood lens (24) may be circular, but the radiation vector from the light emitting surface of LED (1) in Fig. 10 ( As shown in the distribution of Vr), since the intensity of light passing through the peripheral portion of the hood lens (24) is low, the density at which the hood lens (24) is arranged in the main scanning direction (Sx) (for example, z direction) In order to increase the image, the peripheral portion of the hood lens (24) in the main scanning direction (Sx) may be cut off (that is, when the hood lens (24) is viewed from the side, the hood lens (24) Oval shape).
  • the peripheral portion of the hood lens (24) in the sub-scanning direction (Sy) (for example, y direction) is cut off. (Ie, when the hood lens (24) is viewed from the side, the hood lens (24) has a square shape).
  • the entire side surface of the hood lens (24) is preferably a mirror surface.
  • the light incident on the side surface of the hood lens (24) is reflected by the mirror surface to reflect the light incident on the side surface of the hood lens (24) from the lens surface of the hood lens (24).
  • the side surface of the hood lens (24) in the main scanning direction (Sx) may be a non-mirror surface. In the main scanning direction (Sx) (z direction), light that escapes from the side surface of the hood lens can be used effectively by being incident on the adjacent hood lens.
  • the light source including the LED and the rotating paraboloid mirror in the illumination device illustrated in FIGS. 5 to 9 may be replaced with the light source including the LED and the convex lens as illustrated in FIGS. 10 (a) and (b). Good. Further, in the light source as shown in FIG. 10, it is also possible to arrange the convex lens corresponding to the hood lens (24) independently while keeping the tip of the hood flat.
  • the paraboloid as the first focusing means used in the first to third embodiments of the present invention in order to focus the light diffusing from the LED onto the surface to be illuminated (imaging area), the paraboloid as the first focusing means used in the first to third embodiments of the present invention.
  • a spheroidal mirror having a rotation axis coaxial with the rotation axis of the mirror can also be used.
  • the LED light emitting surface is arranged at one of the focal points of the spheroid mirror (for example, the first focus F1) and the focus of the spheroid mirror is used.
  • the second focusing means can be omitted. That is, the spheroid mirror can have both the function of the first focusing means and the function of the second focusing means used in the first to third embodiments of the present invention.
  • FIG. 11 is a view for explaining one example of a lighting device according to the fourth embodiment of the present invention.
  • FIG. 11 (a) is a front view of one example of a lighting device according to the fourth embodiment of the present invention
  • FIG. 1 Kb) shows the fourth embodiment of the present invention in the sub-scanning direction (Sy). It is a figure which shows the illumination intensity distribution given by one example of the illuminating device by.
  • a light source including an LED (1) and a spheroidal mirror (2b) is used, and the center of the light emitting surface of the LED (l) is rotated. It is located at the first focal point F1 of the ellipsoidal mirror (2b).
  • the illumination target surface (imaging region) (Ai) is disposed at the second focal point F2 of the spheroid mirror (2b). The light emitted from the LED (1) is reflected by the spheroid mirror (2b) and enters the illumination lens (3).
  • the light reflected by the spheroid mirror (2b) is diffused by the illumination lens (3) in the main scanning direction (Sx), while it passes through the illumination lens (3) as it is in the sub-scanning direction (Sy). Passes and converges to the position of the second focal point on the illumination target surface (imaging area) (Ai).
  • the illuminance distribution (Each—Di) (Total—Di) on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) is ) Is the same as the illuminance distribution indicated by the two-dot chain line.
  • FIG. 12 is a diagram for explaining another example of the lighting apparatus according to the fourth embodiment of the present invention.
  • FIG. 12 (a) is a front view of another example of the lighting device according to the fourth embodiment of the present invention
  • FIG. b) is a diagram showing the illuminance distribution given by another example of the illumination device according to the fourth embodiment of the present invention in the sub-scanning direction (Sy).
  • the light diffused from the LED (1) is illuminated by changing the focal position of the convex lens (hood lens) (2c) shown in Fig. 10. Focus on the target surface (imaging area) (Ai)!
  • a light source including an LED (l) and a convex lens (2c) is used, and the focal length f of the convex lens (2c) is
  • a is the distance from the light emitting surface of the LED to the principal point of the convex lens (2c)
  • b is the distance from the convex lens (2c) to the illumination target surface (imaging area) (Ai).
  • the light emitted from the LED (1) is focused by the convex lens (2c) and enters the illumination lens (3).
  • the light focused by the convex lens (2c) is diffused by the illumination lens (3) in the main scanning direction, while passing through the illumination lens (3) as it is in the sub-scanning direction (Sy). Focus on surface (imaging area) (Ai).
  • the illuminance distribution (Each-Di) (Total-Di) on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) is This is the same as the illuminance distribution shown by the two-dot chain line in d).
  • FIGS. 11 and 12 can be applied to the examples of the illumination device or the image reading device shown in FIGS.
  • FIG. 13 is a diagram for explaining one example of an illumination device and an image reading device according to the fourth embodiment of the present invention.
  • FIG. 13 (a) is a diagram showing an example of an illumination device according to the fourth embodiment of the present invention
  • FIG. 13 (b) is a diagram of one of the image reading devices according to the fourth embodiment of the present invention. It is a figure which shows an example.
  • the example of the illumination device shown in FIG. 13 (a) is the same as the example of the illumination device shown in FIG. 13 (a).
  • FIG. 13 (a) in addition to the illumination device, a turning mirror (12) of the image reading device is depicted.
  • FIG. 13 (b) shows an example of an image reading device in which the same lighting device as the example of the lighting device shown in FIG. 11 is mounted on the first traveling body (11).
  • the illumination device shown in Fig. 13 (a) is tilted with respect to the reading optical axis (AxR) without bending the illumination optical axis (Axl).
  • the lighting device may be arranged parallel to the surface of the contact glass (13). In this case, the size of the image reading device in the direction perpendicular to the surface of the contact glass (13) can be reduced.
  • FIG. 14 is a diagram for explaining another example of the illumination device and the image reading device according to the fourth embodiment of the present invention.
  • FIG. 14 (a) is a diagram showing another example of an illuminating device according to the fourth embodiment of the present invention
  • FIG. 14 (b) shows another example of the image reading device according to the fourth embodiment of the present invention.
  • FIG. 14 (a) is a diagram showing another example of an illuminating device according to the fourth embodiment of the present invention
  • FIG. 14 (b) shows another example of the image reading device according to the fourth embodiment of the present invention.
  • the turning mirror (12) of the image reading device is drawn in addition to the illumination device.
  • FIG. 14 (b) shows an example of an image reading device in which a lighting device similar to the example of the lighting device shown in FIG. 12 is mounted on the first traveling body (11).
  • the illumination device shown in FIG. 14 (a) is tilted with respect to the reading optical axis (AxR) without bending the illumination optical axis (Axl).
  • the illumination optical axis (Axl) of the illumination device shown in FIG. 14 (a) is bent by the folding mirror (6), so that The lighting device may be arranged parallel to the surface of the contact glass (13). In this case, the size of the image reading device in the direction perpendicular to the surface of the contact glass (13) can be reduced.
  • the light flux is divided before and after the reading optical axis (AxR), and before and after the reading optical axis (AxR). In both cases, the imaging region (Ai) can be illuminated using the divided light flux.
  • an LED that generates light of any one of the three primary colors of blue (B), green (G), and red (R) can be used. Or white
  • LEDs can also be used. However, it is preferable to use a green LED because green is almost representative of human visibility.
  • RGB LEDs blue (B), green (G), and red (red) are connected to the illumination device and image reading device shown in FIGS. R) LEDs may be arranged in combination or alternately, and a color one-dimensional image sensor may be used.
  • blue LEDs are arranged as LEDs L1, L4, L7 ''-, and green LEDs are used as LEDs L2, L5, L8.
  • red LED Arrange and arrange red LED as L3, L6, L9 '... of LED.
  • the number of LEDs that contribute to the illuminance distribution on the illumination target surface (imaging area) is reduced to one-third compared to the case of a single color (for example, 6 times in FIG. 5). Therefore, the characteristics of the illuminance distribution due to the light of each color on the illumination target surface (imaging area) will deteriorate. Therefore, if the gain Q is increased approximately 3 times by shortening the focal length f of the illumination lens and / or increasing the distance g from the illumination lens to the illumination target surface (imaging area), a single color is obtained. An illuminance distribution that is as good as the illuminance distribution in the case of using an LED can be obtained.
  • FIG. 15 is a diagram for explaining an example of the illumination method and illumination apparatus according to the fifth embodiment of the present invention.
  • FIG. 15 (a) is a top view of an example of a lighting device according to the fifth embodiment of the present invention
  • FIG. 15 (b) is a front view of an example of the lighting device according to the fifth embodiment of the present invention. is there.
  • FIG. 5 (c) shows the illuminance distribution (Each— in the main scanning direction (Sx) on the illumination target surface (imaging region) (Ai) obtained by the illumination method example according to the fifth embodiment of the present invention. Di) (Total—Di), and
  • FIG. 5 (d) shows the illumination target surface (imaging area) (Ai) obtained by the example of the illumination method according to the fifth embodiment of the present invention. It is a figure which shows the illumination intensity distribution of the subscanning direction (Sy) of Yes
  • the hood lens of the convex lens (2c) is attached to the red (R), green (G), and blue (B) three-color LED chips (1).
  • This is an example of a color lighting device including a light source.
  • a light source including an LED chip (1) and a convex lens (2c) is used instead of the light source including the LED and the rotating parabolic mirror in the illuminating device shown in FIG.
  • one light source has three types of LED chips (1) for blue (B), green (G), and red (R) arranged in a row (in the main scanning direction in FIG. 15) and arranged in a row.
  • the total power of the three types of LED chips (1) is covered with a hood lens that is a convex lens (2c).
  • the order of arrangement of the three-color LED chips (1) is not particularly limited.
  • the green (G) LED chip (1) is arranged in the center and the green (G) LED chip ( Adjacent to 1), a blue LED chip (1) and a red LED chip (1) are arranged.
  • the illumination target surface (imaging area) (Ai) caused by the single light source L k including the LED chip (1) of three colors (B, G, R) and the convex lens (2c) Illuminance distribution (Each—Di) (Total—Di) will be described.
  • the optical axis of the green luminous flux generated from the green (G) LED chip (1) coincides with the optical axis of the convex lens (2c).
  • the green luminous flux generated from the green (G) LED chip (1) behaves exactly the same as the luminous flux generated from the LED in Fig. 5.
  • the width of the cylinder lens constituting the illumination lens (3) that is, the width of the light source
  • the illumination target surface (imaging region) (Ai) is irradiated with a green light beam having a double width.
  • the Q length is 2 or more.
  • the optical axis of the red light flux generated from the red (R) LED chip (1) is slightly shifted from the optical axis of the convex lens (2c), the red (R) LED chip (1 ), The red light beam that passes through the convex lens (2c) and the green light generated from the green (G) LED chip (1).
  • the ratio of the width of the red luminous flux in the illumination target surface (imaging area) (Ai) to the width of the cylinder lens that constitutes the illumination lens (3), that is, the width of the light source Q is the green (G) LED chip ( This is the same as the value for the green luminous flux generated from 1).
  • the optical axis of the blue luminous flux generated from the blue (B) LED chip (1) is slightly shifted from the optical axis of the convex lens (2c), so the blue (B) LED chip (1)
  • the blue luminous flux generated from the lens passes through the convex lens (2c) and is slightly below the green light flux generated from the green (G) LED chip (1), and the illumination target surface (imaging area) ( Irradiate Ai).
  • the ratio of the width of the blue luminous flux in the illumination target surface (imaging area) (Ai) to the width of the cylinder lens that constitutes the illumination lens (3), that is, the width of the light source Q is the green (G) LED chip ( This is the same as the value for the green luminous flux generated from 1).
  • the colored luminous flux is indicated by a solid line, and the blue luminous flux is indicated by a thin broken line.
  • the concept of the illuminance distribution on the illumination target surface (imaging area) (Ai) for each of the three colors is shown as an individual illuminance distribution (Each Di) in Fig. 15 (c). Also, other light sources, L, L, L, L
  • the illuminance on the illumination target surface (imaging area) (Ai) on the optical axis of the light source also contributes to the illuminance of the luminous flux generated from the light source in the circumference k k of the light source.
  • the total illuminance distribution (Total—Di) due to the whole of these light sources is also shown in Fig. 15 (c).
  • the illumination device shown in Fig. 15 does not include the focusing lens (4a), the parallel luminous flux of each color that has passed through the illumination lens (3) remains as it is as the illumination target surface (imaging region) ( Ai) To do.
  • the illuminance distribution (Di) on the illumination target surface (imaging region) (Ai) in the sub-scanning direction (Sy) has a broad distribution as shown by the solid line in FIG.
  • the illumination device shown in FIG. 15 is provided between the illumination lens (3) and the illumination target surface (imaging region) (Ai) and is illuminated by the illumination target surface (imaging region) (Ai) force focal length F.
  • the focusing lens (4a) disposed at the position is included, the parallel luminous flux of each color that has passed through the illumination lens (3) is focused on the illumination target surface (image area) (Ai).
  • the illuminance distribution on the illumination target surface (imaging area) (Ai) in the sub-scanning direction (Sy) has a sharp distribution (Each_Di) (Total— Di).
  • the focal length f of the convex lens (2c) is set as follows. Similar to the example of the lighting device in FIG.
  • a is the distance from the light emitting surface of the LED chip (1) to the principal point of the convex lens (2c), and b is from the principal point of the convex lens (2c) to the illumination target surface (imaging area) (Ai). Is the distance. In this case, it is not necessary to provide the focusing lens (4a).
  • the illumination device as shown in FIG. 15 When the illumination device as shown in FIG. 15 is mounted on the first traveling body of the image reading device, the illumination device as shown in FIG. 15 is replaced with the image reading device as shown in FIGS. It can be applied to.
  • FIG. 16 is a view for explaining an example of the illumination method and the image reading apparatus according to the sixth embodiment of the present invention.
  • FIG. 16A is a top view of an example of the image reading apparatus according to the sixth embodiment of the present invention
  • FIG. 16B is a front view of the example of the image reading apparatus according to the sixth embodiment of the present invention. It is a figure.
  • FIG. 16 (c) is a diagram showing the illuminance distribution in the sub-scanning direction on the illumination target surface (imaging area) obtained by the example of the illumination method according to the sixth embodiment of the present invention.
  • An example of an image reading apparatus as shown in Fig. 16 is a hood lens with a convex lens (2c) in a batch of three red LED chips (1) of red (R), green (G), and blue (B). 1 is an example of a color image reading apparatus using a light source with a light attached.
  • the arrangement of the three-color LED chips (1) of the illumination system is such that the one-dimensional imaging element (15) of the reading system for reading the image of each color Can be associated with
  • the system on the left side of the illumination target surface (imaging region) (Ai) is the illumination system
  • the system on the right side of the illumination target surface (imaging region) (Ai) is the reading system. It is a system.
  • the imaging area (Ai) is illuminated using the illumination system, and the image of the original placed in the imaging area (Ai) is read by the reading system.
  • the reading system of the color image reading apparatus uses a three-line CCD in which three one-line CCDs (-dimensional imaging device (15)) are arranged in parallel. Each of the three 1-line CCDs is provided with a color filter (18) that transmits red (R), green (G), or blue (B). Read the color image that passes through the filter (18).
  • a three-line CCD equipped with such a power color filter (18) cannot simultaneously read images at the same location in the imaging area (Ai) of the document.
  • the size of the pixel constituting the 600 dpi image is 42.3 m.
  • the reading system of the current image reading device is a reduction optical system, and in the image sensor, the reading system is Corresponds to 10 ⁇ , 7 ii m, or 4 ⁇ 7 m, depending on the reduction ratio.
  • the three 1-line CCDs need to be separated from each other by a distance corresponding to 3 to 4 pixels.
  • the interval between the three 1-line CCDs is roughly equivalent to 0.4 to 0.2 mm in the image area (Ai) on the document surface.
  • red, green, and blue images are read at intervals of 0.4 to 0.2 mm in the imaging area (Ai) on the original surface. Therefore, the red, green, and blue light fluxes generated from the red, green, and blue LED chips (1) are irradiated at intervals of 0.4 to 0.2 mm in the imaging area (Ai) of the document surface. It is preferable.
  • MO is the distance between the LED chips (1) of each color
  • ml is the distance between the centers of the light fluxes of each color from the LED chips (1) of each color passing through the focusing lens (4a)
  • Fig. 16 (c) shows the illuminance distribution in the sub-scanning direction (Sy) of the image reading device shown in Figs. 16 (a) and 16 (b).
  • the arrangement of the colors R, G, B is assumed to be on a straight line in the main scanning direction (Sx) or the sub-scanning direction (Sy).
  • the arrangement of the colors S, R, G, B There is no particular limitation, and for example, the colors of R, G, and B may be arranged at the vertices of a triangle, the letter “K” in hiragana, or the letter “L” in English. In such a case, an optimum design of the illumination device and the image reading device can be achieved by combining the ideas as shown in FIGS.
  • FIG. 17 is a view for explaining one example of the illumination method and illumination apparatus according to the seventh embodiment of the present invention.
  • FIG. 17 (a) is a perspective view of an example of an illuminating device according to the seventh embodiment of the present invention
  • FIG. 17 (b) is an image reading device according to the seventh embodiment of the present invention.
  • FIG. 17 (c) is a side view of one example of an image reading apparatus according to the seventh embodiment of the present invention.
  • FIG. 17 (d) is a diagram showing the illuminance distribution in the main scanning direction on the illumination target surface (imaging region) obtained by one of the illumination methods according to the seventh embodiment of the present invention.
  • an example of an illumination device as shown in FIG. 17 is a rectangular light emitting surface in the main scanning direction (Sx) between a plurality of LEDs (1) having a rectangular light emitting surface and an illumination target area (Ai). Cylinder lens array illumination that diffuses the luminous flux generated by multiple LEDs (1) Includes lens (3). Then, between the plurality of LEDs (1) having a rectangular light emitting surface and the illumination lens (3), a plurality of LEDs (1) having a rectangular light emitting surface in the sub-scanning direction (Sy)!
  • a focusing lens (4a) for the cylinder lens that focuses the luminous flux generated from the lens is inserted.
  • the concept of setting the focal length of the illumination cylinder lens is the same as that in the first to sixth embodiments.
  • the focusing lens (4a) is shown to be focused as shown in FIG. 17 (c).
  • a plurality of LEDs (1) having a rectangular light emitting surface are used.
  • the generated light beam may be converted into parallel light or diffused light that is not necessarily focused.
  • the insertion of the focusing lens (4a) is not always essential.
  • each of the plurality of LEDs (1) having a rectangular light emitting surface in the main scanning direction (Sx) is provided.
  • the luminous flux generated by the force not only enters the cylinder lens of the illumination lens (3) corresponding to each LED (1), but also the cylinder lens of the illumination lens (3) corresponding to each LED (1). It also enters the cylinder lens in the vicinity (or adjacent to the cylinder lens).
  • the luminous flux generated by each of the plurality of LEDs (1) having a rectangular light emitting surface is further diffused by the illumination lens (3).
  • the light beam diffused from L4 of LED (1) is mainly incident on the cylinder lens corresponding to L4 of LED (1), and has a preset magnification. Then, the surface to be illuminated (imaging area) (Ai) is irradiated. However, a part of the light beam diffused from L4 of LED (l) also enters the cylinder lens corresponding to L3 and L5 of LED (1) adjacent to L4 of LED (1). In addition, a part of the light beam diffused from L4 of LED (1) is also incident on the cylinder lens corresponding to L2 and L6 of LED (l) located near L4 of LED (l). As a result, in the example of the illuminating device as shown in FIG. 17, it is possible to diffuse light S generated from the LED (1) more widely.
  • the main scanning direction (Sx)! Therefore, it is possible to significantly reduce fluctuations in the illuminance distribution on the illumination target surface (imaging area) (Ai) due to variations in the luminous efficiency of multiple LEDs (1). That is, in the conventional illumination device as shown in FIG. 4, in the main scanning direction (Sx), the illumination target surface illuminated by the LED (1) having lower luminous efficiency (imaging) The ratio of illuminance hi on the illumination target surface (imaging area) (Ai) illuminated by the LED (1) with higher luminous efficiency relative to the illuminance h2 in area (Ai) is approximately double.
  • the illuminating device as shown in FIG. 17 since the range of light beam diffusion in the main scanning direction (Sx) is wider, it is effective to provide side mirrors (5a, 5b) in the illuminating device. It is effective to install the side mirrors (5a, 5b) up to the side of LED (1). In this case, it is possible to irradiate the illumination target surface (imaging region) (Ai) with the diffused light from the LED without diffusing outside the illumination target region (Ai) in the main scanning direction (Sx). it can.
  • FIG. 18 is a diagram for explaining another example of a lighting device according to the seventh embodiment of the present invention.
  • FIG. 18 (a) is a top view of another example of an illuminating device according to the seventh embodiment of the present invention
  • FIG. 18 (b) is a diagram of another example of the image reading device according to the seventh embodiment of the present invention. It is a front view.
  • a parabolic mirror (2d) is used instead of the condenser lens (4a) in the example of the illumination device as shown in FIG. As shown in Fig. 17, LEDs with rectangular light-emitting surfaces are used side by side.
  • the parabolic mirror (2d) has a parallel plane cross section in the main travel direction (Sx) and a cross section of the paraboloid in the sub-scan direction (Sy)! Have
  • the illumination device as shown in FIG. 18, there is no barrier against the luminous flux generated by each of the plurality of LEDs (1) in the main scanning direction (Sx), so that as shown in FIG.
  • the luminous flux generated from each LED (1) not only enters the cylinder lens of the illumination lens (3) corresponding to each LED (1), but also each LED (1 It is also incident on the cylinder lens).
  • the luminous flux generated from each LED (1) is further diffused by the illumination lens (3).
  • L4 one of the LEDs (1)
  • the scattered light beam mainly enters the cylinder lens corresponding to L4 of the LED (1), and illuminates the illumination target surface (imaging area) (Ai) at a preset magnification.
  • the diffusion range of the light flux in the main scanning direction (Sx) is wider, it is effective to provide the side mirrors (5a, 5b) in the illuminating device. It is effective to provide the side mirrors (5a, 5b) up to the side of the parabolic mirror (2d). In this case, it is possible to irradiate the illumination target surface (imaging region) (Ai) without diffusing the diffused light from the LED outside the illumination target region (Ai) in the main scanning direction (Sx). it can.
  • the illumination device shown in FIG. 18 includes a focusing lens (4a), but the focusing lens (4a) is not necessarily an essential component.
  • a force S using a parabolic mirror (2a) is used as the first bundling means, and an ellipsoidal mirror is used as the first focusing means. it can.
  • the ellipsoidal mirror has a parallel plane section in the main scanning direction (Sx), and an ellipsoidal section in the sub-scanning direction (Sy).
  • the first focal point of the elliptical surface of the elliptical mirror is located at the center of the light emitting surface of the LED, and the second focal point of the elliptical surface of the elliptical mirror is located in the illumination target area (Ai).
  • the focusing lens (4a) becomes unnecessary.
  • an illumination device for a color image reading device using independent LEDs of three colors R, G, and B will be described.
  • the LEDs L ;! to L7 as shown in FIG. 17 are formed of one color LED and the other two color LEDs are added.
  • the other two colors (R and B) LEDs are arranged on both sides of the one color (G) LED in the sub-scanning direction (Sy). It is possible to provide a light source composed of colored LEDs.
  • FIG. 19 is a diagram for explaining an example of a lighting apparatus according to the eighth embodiment of the present invention.
  • FIG. 19 (a) is a top view of another example of an illuminating device according to the eighth embodiment of the present invention, and
  • FIG. 19 (b) shows another image reading device according to the eighth embodiment of the present invention. It is a front view of an example.
  • a cylinder lens array composed of a plurality of adjacent convex cylinder lenses has been shown as the illumination lens.
  • a cylinder lens array composed of a plurality of concave cylinder lenses arranged adjacent to each other can also be used.
  • a cylinder lens array composed of a plurality of adjacent concave cylinder lenses is used as the illumination lens (3). Even when a cylinder lens array composed of a plurality of contiguous concave cylinder lenses is used as the illumination lens (3), the luminous flux generated from the LED (1) is transmitted in the main scanning direction ( In Sx), it is possible to diffuse S.
  • the focal length force of each concave cylinder lens that constitutes the cylinder lens array, and the illumination target surface (imaging area) (Ai) from the principal point of the concave cylinder lens corresponding to one of the LEDs (1) If the distance force up to 3 ⁇ 4, the expansion factor Q of the width of the luminous flux of light emitted from one of the LEDs (1) in the main scanning direction (Sx) is
  • Q is 2 or more.
  • the reading system including the document table (container glass), the imaging lens, and the one-dimensional imaging device in the image reading device is fixed, while the first The traveling body and the second traveling body move differentially in the sub-scanning direction.
  • the illuminating device by the 1st-8th Example of this invention is mounted in a 1st traveling body. Except for the lighting device, the first traveling body is equipped only with a turning mirror that bends the optical path of the light reflected from the imaging region, so that the mass of the first traveling body does not increase and the first traveling body does not increase. Reading an image by moving the row body and the second traveling body is suitable for high-speed reading. However, if low-speed reading is permitted, it is conceivable that a reading device is also mounted on the first traveling body. In this case, since the second traveling body is unnecessary, only one traveling body may be provided. ).
  • FIG. 20 is a view for explaining an example of an image reading apparatus according to the ninth embodiment of the present invention.
  • FIG. 20 (a) is a diagram for explaining an example of an image reading apparatus according to the ninth embodiment of the present invention
  • FIG. 20 (b) is an illustration of the image reading apparatus according to the ninth embodiment of the present invention. It is a figure explaining another example.
  • the illumination unit (10) as the illuminating device according to the first to eighth embodiments of the present invention reads as a reading system. It is mounted on the traveling body (11a) together with the unit (16). Since the reading unit (16) is a reduction optical system including an imaging lens and an imaging element, a certain distance from the document surface to the imaging lens is required.
  • the image light reflected from the document surface is once redirected by the deflecting mirror (12) in the direction parallel to the contact glass (13). After being folded, the two folding mirrors (17a) and (17b) are each folded twice and guided to the reading unit (16).
  • the image light reflected from the document surface is folded back diagonally to the upper right by the turning mirror (12), and the first folding mirror ( After being changed in a direction parallel to the contact glass (13) by 17a), it is directed to the second folding mirror (17b).
  • the light incident on the second folding mirror (17b) is reflected again slightly downward and returned again to the first folding mirror (17a).
  • the light returned to the first folding mirror (17a) is reflected obliquely downward, further reflected by the third folding mirror (17c), and in a direction parallel to the surface of the contact glass (13), Guided to reading unit (11).
  • a reading system such as a reading unit (11) and an illumination unit.
  • any of the illumination devices according to the first to eighth embodiments of the invention is used as the illumination unit (10). Can it can.
  • the lighting device shown in Fig. 7 (e) is directly adopted.
  • a convex lens is used instead of the rotary parabolic mirror as the first focusing means in the image reading apparatus shown in FIG. 20 (a).
  • the illuminating device and the illuminating method for mounting on a reduction optical system or a digital image reading device that reads an image with an image sensor has been described.
  • the illumination apparatus and illumination method as shown in the first to ninth embodiments of the present invention can also be used as an illumination method for mounting in an equal magnification optical system or an analog copying machine.
  • FIG. 21 is a diagram for explaining an example of an image reading apparatus according to the tenth embodiment of the present invention.
  • An example of the image reading apparatus as shown in FIG. 21 is an image reading apparatus for an image forming apparatus that copies a sheet-like document.
  • the imaging lens (14) is a microlens array, and a number of aperture lenses are arranged so as to have the same length as the width of a sheet document (33) such as a length lens of the microlens array. It is a thing.
  • the imaging lens (14) is arranged between the imaging area (Ai) and the photoconductor (31) in order to provide an equal-magnification optical system.
  • the sheet document (33) is pressed and fed by the paper feed roller (32) in the imaging region (Ai) portion on the contact glass (13) with little friction with the sheet document (33).
  • the photoconductor (31) is moved in synchronization with the feeding of the sheet document (at the same speed). Note that illustration of peripheral devices of the photosensitive member such as a charging device and a transfer device for charging the photosensitive member (31) is omitted.
  • the illuminating apparatus is obtained by removing the traveling body and changing the position of the folding mirror in the illuminating apparatus shown in FIG. 7 (b).
  • the imaging area (Ai) of the sheet original (33) is illuminated one-dimensionally, and the image on the sheet original (33) is transferred to the photoconductor (14) via the imaging lens (14). 31) Projecting above.
  • the entire image on the sheet original (33) can be projected as a two-dimensional image on the photosensitive member (31). it can.
  • FIG. 22 shows the illuminance distribution in the imaging area (Ai) in the image reading apparatus using the reduction optical system.
  • FIG. 22 (a) is a diagram showing the arrangement of the imaging area (Ai), imaging lens, and one-dimensional CCD in an image reader using a reduction optical system.
  • Fig. 22 (b) shows (1) results. It is a figure explaining the relationship between the brightness distribution of the image imaged on one-dimensional CCD by an image lens, and the illuminance distribution (Di) requested
  • a one-dimensional CCD is placed parallel to the imaging area (Ai), and an imaging lens (14) is placed between them to form an image on the one-dimensional CCD.
  • an imaging lens (14) is placed between them to form an image on the one-dimensional CCD.
  • the imaging lens (14 ) when an image in the imaging region (Ai) is imaged on a one-dimensional CCD as a one-dimensional imaging device (15) by the imaging lens (14), the imaging lens (14 ), the imaging lens (14 ), the imaging lens (14 ), The brightness of the image on the periphery of the one-dimensional CCD is lower than the brightness of the image on the center of the one-dimensional CCD.
  • W is the length of the imaging region (Ai) in the main scanning direction (Sx), and the imaging lens (14) is moved in the vertical direction at the center of the imaging region (Ai). If the Ld is the distance from the imaging region (Ai) to the imaging lens (14), it is incident on the imaging lens (14) with respect to the optical axis of the imaging lens (14).
  • the maximum angle ⁇ of the ray angle ⁇ is
  • the relative value of the brightness of the image formed by the imaging lens (14) at each position in the main scanning direction (Sx) on the one-dimensional CCD is determined according to the so-called cosine fourth law. It changes with cos 4 ⁇ as shown in curve (1) of Fig. 22 (b) with respect to the angle ⁇ of the light ray incident on the imaging lens from the position in the imaging region (Ai) corresponding to.
  • the imaging lens (14) The brightness of the image on the one-dimensional CCD imaged by) is reduced by several tens of percent.
  • the amount of light incident on the one-dimensional CCD is converted into an electric signal by the one-dimensional CCD. Therefore, after converting the amount of light into an electric signal, the amplification factor of the electric signal is changed to form an image. It is possible to correct the difference in brightness of the image formed by the lens (14). However, in this case, since the dynamic range is reduced, noise increases around the one-dimensional CCD where the brightness of the image formed by the imaging lens (14) is relatively low. As a result, the image read by the one-dimensional CCD becomes dirty.
  • the optical axis of the imaging lens (14) is placed on the imaging region (Ai) side of the imaging lens (14) so as to be inversely proportional to the relationship shown by the curve (1) in Fig. 22 (b).
  • the power to insert a light shielding mask that increases the amount of light shielded from the position of the nearby imaging area (Ai), or the reflectance of the reflector that reflects light from the light source It is also possible to make the illuminance of the light imaged on the one-dimensional CCD constant by changing the reflectivity at the center of the LED to be low. In such a case, the correction of the electric signal can be reduced. However, it is not desirable from the viewpoint of energy saving to block or discard the light emitted from the light source.
  • the imaging region (Ai) is obtained so that the illuminance distribution (Di) required for the imaging region (Ai) shown in the curve (2) in Fig. 22 (b) without throwing away the luminous flux that also generates the light source power. ) Should be illuminated. Then, the utilization efficiency of the light emitted from the light source can be improved, and as a result, the energy S for reducing the energy of the light illuminating the imaging area (Ai) (achieving energy saving) can be reduced.
  • the interval between a plurality of light sources such as LEDs is used.
  • FIG. 23 is a diagram for explaining a method for determining the arrangement intervals of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of the image formed on the one-dimensional CCD is constant. is there.
  • the arrangement interval of a plurality of light sources (for example, LEDs) that illuminate the imaging target area (Ai) is set at the center ( It narrows away from the imaging lens.
  • the arrangement shown in FIG. 22 (a) is shown rotated by 90 degrees counterclockwise. In the symbols shown there, the same symbols as those in FIG. 22 have the same meaning.
  • Wh is half the length W of the imaging target area (Ai) in the main scanning direction (Sx), and is calculated from the center of the imaging target area (Ai).
  • the sub-scanning direction (Sy) In order to calculate the interval between multiple light sources that illuminate the imaging target area (Ai) so that the relative brightness of the image formed on the one-dimensional CCD is constant, the sub-scanning direction (Sy) The design or simulation is based on the premise that the light source power and other luminous fluxes do not diverge. Specifically, in the sub-scanning direction (Sy), the imaging target area (Ai) is illuminated using light emitted from a plurality of light sources as parallel light, or light emitted from a plurality of light sources is to be imaged. Adopt either the force focused on the area (Ai), or somewhere in between.
  • the upper half region and the center line of FIG. 23 (the optical axis of the imaging lens) Since the lower half region is symmetrical, only the lower half region will be described for convenience of explanation.
  • the lower half area half of the imaging target area (Ai) in the main scanning direction (Sx)
  • the point on the center line is set as the origin.
  • the point number of the origin is set to 0, and the point numbers of each division point are numbered l to n in the order from the origin, and the interval from origin 0 to division point 1 is divided from division point 1.
  • the interval from point 2 to ..., and the interval from division point n—1 to end point n are represented by wl, w2,.
  • the interval between wl and wn is obtained so that the illuminance distribution (Di) required for the imaging target area (Ai) shown in the curve (2) in Fig. 22 (b) is obtained.
  • the N division of the area (half of the imaging target area (Ai) in the main scanning direction (Sx)) is initially divided into N equal parts. Then, assuming that the entire area to be imaged (Ai) is illuminated with a constant illuminance, the relative brightness of the position corresponding to each division point imaged on the one-dimensional CCD by the imaging lens is expressed by the cosine fourth law. So ask. Specifically, the relative brightness of the image formed on the one-dimensional CCD by the imaging lens corresponding to the kth division point on the imaging target area (Ai) is cos 4 ⁇ . Also this
  • ⁇ is the center of the imaging lens and the area to be imaged with respect to the optical axis of the imaging lens.
  • ⁇ is the angle of a straight line connecting the center of the imaging lens and the nth division point with respect to the optical axis of the imaging lens and coincides with ⁇ max.
  • the distance between the division points is given again by division in proportion to the relative brightness corresponding to each division point. That is, the intervals wl, w2, ...
  • the relative brightness of the image formed on the two-dimensional CCD is obtained by the cosine fourth law. Specifically, the relative brightness of the image formed on the one-dimensional CCD corresponding to the kth division point is co s 4 0 ′. The sum of the relative brightness is
  • FIG. 24 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of an image formed on the one-dimensional CCD is constant.
  • FIG. 24 (a) is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface where the side mirrors are arranged
  • FIG. 24 (b) is a diagram showing an example of the radiation characteristics of the light sources.
  • FIG. 24 (a) is an enlarged view of a portion expressed on the left side of the imaging target surface (imaging target area) (Ai) in FIG.
  • the distance from the illumination target area (imaging target area) (Ai) by L0 and parallel to the imaging target area (Ai) was obtained in the above description.
  • a light source is placed at each obtained division point.
  • a mirror surface (side mirror) is placed at the position of the outside PM1, and the relative illuminance at each position of the imaging target area (Ai) is calculated.
  • This mirror surface reflects the luminous flux emitted from a plurality of light sources placed on the light source arrangement position corresponding to the point where the range of the imaging target area (Ai) is divided, and the light force is also on the extension line of the light source. Is The area of the illumination target area (Ai) is illuminated as if.
  • n + 1 light sources obtained by dividing half of the imaging target area (Ai) in the main scanning direction (Sx) by N are denoted by P 1, P 2, ⁇ ' ⁇ ⁇ and ⁇
  • the positions of the arranged light source images are ⁇ , ⁇ , ⁇ ' ⁇ ⁇ .
  • the distance between the light source located at ⁇ n + 1 n + 2 2n + ln and the image of that light source obtained by the side mirror located at P is obtained by deducting the above calculation method . Since the position P and the position P are in a mirror image relationship with the side mirror, the mirror surface of the side mirror is provided at a position half the distance between the position P and the position P. Furthermore, when the above calculation method is deduced and the interval between the position P and the position P, and the interval between the position P and the position P are obtained, the position P
  • the interval is wide because it is a virtual image with a mirror surface (naturally, the interval between position P and position P, ..., position P and
  • the distance from position P is the distance between position and position P, respectively.
  • a side mirror that is paired with the side mirror provided outside the nth light source is also provided in the upper half of the center line of the imaging target area (Ai) (the optical axis of the imaging lens). (Position of PM2)
  • the side mirrors provided outside the nth light source are arranged in parallel to each other. For this reason, the force S that generates an unlimited number of virtual light sources that are mirror images by the pair of side mirrors, of which the virtual light source that is generated by two or more reflections by the side mirrors is far from the imaging target area (Ai). Therefore, the contribution ratio to the illuminance distribution (Di) in the imaging target area (Ai) is extremely small and can be ignored.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) illuminated by a plurality of light sources is determined. If the angle of the vertical line to the imaging target area (Ai) and the directional force of the light source from the light source to the point Mm and the radiation vector of the emitted light is ⁇ , the distance from the light source to the imaging target area (Ai) is L0. Therefore, the distance from one light source to the point Mm is LO / cos a.
  • the light at point Mm in the imaging target area (Ai) illuminated by the light emitted from each light source Intensity from each light source to point Mm Inversely proportional to the distance LO / cos a. Furthermore, the degree of decrease in luminous flux due to the tilt of the surface at the same point Mm is cos a.
  • the intensity of the light emitted from the light source in the direction of the radiation vector that forms an angle ⁇ with the vertical line with respect to the imaging target area (Ai) is the emission of the light emitted from the light source.
  • the radiation vector distribution (envelope) of a light source such as an actual LED has a complicated shape, but it is approximated by a circle or ellipse for convenience of calculation. For example, as shown in (1) of Fig.
  • A is the relative value of the total amount of light emitted by the kth light source.
  • ⁇ is the direction force at the point Mm with respect to the direction of the optical axis of the imaging lens, and the radiation plate k of the kth light source
  • the center line of the imaging target area (Ai) (illuminated by the entire light source placed in the upper half of the CU Illuminance distribution over the entire area (Ai) can be obtained, and the center line of the imaging target area (Ai) (the imaging target area (Ai) illuminated by the entire light source placed in the lower half from the CU)
  • the center line of the imaging target area (Ai) (the imaging target area (Ai) illuminated by the entire light source placed in the lower half from the CU)
  • the luminous flux emitted from the light source is used for both the center line (when calculating the lower half from the CU and when calculating the upper half, so the relative intensity A of the light source was placed at other positions.
  • FIG. 5 is a diagram showing a specific example of a target illuminance distribution (required illuminance distribution) when illuminating the imaging target area (Ai) so that the relative brightness of an image formed on the one-dimensional CCD is constant. .
  • the degree of illuminance that must be improved at both ends of the imaging target area (Ai) is 123% with respect to the illuminance at the center of the imaging target area (Ai).
  • the degree of illuminance that must be improved at both ends of the imaging target area (Ai) is 156% with respect to the illuminance at the center of the imaging target area (Ai). .
  • Figure 26 (b) is a diagram (enlarged view) showing the difference between the calculated relative illuminance I (Mm) and the required relative illuminance.
  • the graph (1) shows the illuminance distribution in the entire area to be imaged (Ai) illuminated by the light source in the center line (CU force, half area). 2) shows the illuminance distribution over the entire area to be imaged (Ai) illuminated by the light source in the other half of the area on the opposite side of the graph (1) .
  • Graph (3) shows the graphs (1) and (2 Graph (4) is normalized so that the center value of graph (3) is 100.
  • Graph (5) is the same as graph (4) and Fig. 26 (a). This is the difference from graph (4) in Fig. 25.
  • the imaging target area (Ai) The illuminance distribution near both ends of the [0252]
  • the difference shown in the graph (7) is less than ⁇ 1 (%), and the difference shown in the graph (6) is also less than ⁇ 2 (%). That is, the relative illuminance of the imaging target area (Ai) illuminated by a plurality of light sources can be brought close to the target illuminance distribution with very high accuracy.
  • the width of the area illuminated by the light source in the main scanning direction (Sx) is increased by about 2 to 3% (or illumination by the light source in the main scanning direction (Sx)).
  • the illuminance distribution of the imaging target area (Ai) illuminated by the light source can be further adapted to the target illuminance distribution.
  • the difference between the illuminance distribution of the imaging target area (Ai) illuminated by the light source and the target illuminance distribution can be less than ⁇ 1%. It is.
  • the above-mentioned difference in which the fluctuation of the illuminance distribution due to errors in parts accuracy or assembly accuracy is larger than the above difference is not a problem.
  • FIG. Fig. 27 is a diagram for realizing an illuminating device that matches the illuminance distribution of the light that illuminates the imaging target area (Ai) with the 1 / cos 4 ⁇ characteristic by adjusting the interval between the plurality of light sources.
  • FIG. Fig. 27 (a) is a top view of an example of an illuminating device that matches the illuminance distribution of the light that illuminates the imaging target area (Ai) to the 1 / cos 4 ⁇ characteristic by adjusting the interval between the multiple light sources. Yes, it shows one of the peripheral parts of the imaging target area (Ai) (the other peripheral part from the central part is omitted).
  • Figure 27 (b) shows an illumination that matches the illuminance distribution of the light that illuminates the imaging area (imaging target area) (Ai) with the 1 / cos 4 ⁇ characteristic by adjusting the interval between the multiple light sources. It is a front view of the example of an apparatus.
  • the illumination device includes a plurality of LEDs arranged in the main scanning direction (Sx) as a plurality of light sources.
  • the luminous flux of light emitted from each LED is collimated by a hood lens that is a convex lens corresponding to the LED, then condensed once by an illumination lens (3) that is a cylinder lens, and then diverged.
  • the illumination target area (Ai) is illuminated.
  • the plurality of LEDs are arranged so that the interval between the plurality of LEDs becomes narrower from the vicinity of the center line of the lighting device toward the periphery of the lighting device in accordance with the result of the above simulation.
  • the order of the number k of the LED spacing w in Fig. 27 (a) is k
  • the positions P to P of the respective light sources that are separated from the area (Ai) by the distance L0 are the illumination devices shown in FIG.
  • the position corresponds to the focal position (focal length f) of the cylinder lens corresponding to each LED.
  • the focus position of the cylinder lens corresponding to each LED can be regarded as a virtual light source position.
  • the configuration of the illumination device in the eleventh embodiment in the sub-scanning direction (Sy) is the same as that of the illumination device in the first to ninth embodiments of the present invention in the sub-scanning direction (Sy). There is no need to change.
  • Fig. 27 (b) the light flux emitted from each LED is converted into parallel light by the hood lens corresponding to the LED, and then transmitted through the illumination lens (3), which is a cylinder lens, as parallel light.
  • the method of focusing on the illumination target area (Ai) by the focusing mirror (4b) is shown.
  • a plane mirror is used instead of the focusing mirror to irradiate the imaging target area (Ai) as parallel light, it does not deviate from the results of the above simulation.
  • a hood lens that is a convex lens is used as a means for collimating the light emitted from the LED of the light source.
  • a hood lens that is a convex lens is used as a means for collimating the light emitted from the LED of the light source.
  • the hood lens instead of the hood lens, as shown in FIG. You can use a rotating parabolic mirror!
  • the intervals between the plurality of light sources arranged in the main scanning direction (SX) are set according to the simulation results as described above. It may be changed.
  • a set of red (R), green (G), and blue (B) LEDs is used as a light source.
  • the interval between the red (R), green (G), and blue (B) LED pairs may be changed according to the simulation results described above. .
  • the illuminance distribution of light that illuminates the imaging target area (Ai) by adjusting the distance from each of the plurality of light sources to the imaging target area (Ai) is 1 / cos 4
  • An example of matching with the characteristic of ⁇ is shown.
  • FIG. 28 is a diagram for explaining how to obtain a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of the image formed on the one-dimensional CCD is constant. It is.
  • FIG. 28A is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface on which the side mirror is arranged
  • FIG. 28B is a diagram showing an example of the radiation characteristics of the light sources.
  • the interval between the plurality of light sources in the main scanning direction (Sx) is constant, but the illumination target region (imaging target region) (Ai) from each of the plurality of light sources Change the distance to.
  • the symbol in FIG. 28 is the same force as the symbol in FIG. 24.
  • the intervals between the plurality of light sources wl, w2, ••• wnii are constant and equal to Wh / N.
  • the intervals wl, w2, •• wntt of a plurality of light sources, and half the length Wh of the imaging target area (Ai) in the main scanning direction (Sx) are given by N.
  • ⁇ is the center of the imaging lens relative to the optical axis of the imaging lens Is an angle of a straight line connecting the kth division point on the imaging target area (Ai). That is, the illumination target surface (imaging area) (Ai) from the light source arranged at the kth position P among the plurality of light sources.
  • the distance Lk to is imaged by the imaging lens according to the cosine fourth law with respect to ⁇ .
  • the decrease in brightness of the captured image is captured from the position P of the light source provided on the optical axis of the imaging lens.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) irradiated with light emitted from a plurality of light sources is the same as that in the first embodiment of the present invention. In the same way, the formula
  • FIG. 29 shows the difference between the calculation result of relative illuminance I (Mm) and the required relative illuminance among the simulation results of relative illuminance in the twelfth and subsequent embodiments of the present invention.
  • the imaging target area (Ai) Since the position P force is also a virtual light source that is a mirror image of the light source up to position P, the imaging target area (Ai)
  • the illuminance distribution can be controlled to some extent.
  • the maximum value of the difference shown in graph (1) in Fig. 29 is about ⁇ 3%, even if this is the case.
  • the force S which is about twice the maximum value of the difference shown in Fig. 26, and the accuracy of the parts From the point of view of assembly accuracy and energy saving! (Even if you change the amplification factor of the electrical signal after converting the light amount into an electrical signal with a one-dimensional CCD and correct the difference, the change in the amplification factor is not affected by the small noise.)
  • FIG. 30 is by adjusting the distance from each of the plurality of light sources to the imaging area (imaging target region) (Ai), the illuminance distribution of the light illuminating the imaging area (Ai) l / cos 4 6 It is a conceptual diagram for implement
  • FIG. 30 (a) is a top view thereof
  • FIG. 30 (b) is a front view thereof. Note that the method of embodying the concept shown in FIG. 30 and mounting it on the first traveling body is in accordance with the method of Example 11 described above, and can be easily implemented by those skilled in the art.
  • FIG. 31 is a diagram for explaining an example of a method for changing the radiation characteristic of light emitted from a light source.
  • FIG. 31 is a view seen from the same direction as the top view shown in FIG. In FIG. 31, the front view is omitted, but the same configuration as FIG. 30 (b) is shown.
  • the light source LED is placed at the focal point of the convex lens (focal length fO) which is also a hood.
  • a convex cylinder lens (focal length fl) having the same focal length as that of the convex lens is arranged on the front surface of the convex lens so that the optical axis of the convex lens coincides with the optical axis of the convex cylinder lens.
  • a virtual light source having radiation characteristics similar to the radiation characteristics of the light emitting source can be formed at the focal position of the convex cylinder lens. For example, as shown in (1) of FIG.
  • the relationship between the shape of the convex lens and the shape of the convex cylinder lens is any one of (1), (2) and (3) in FIG. Are arranged in the main scanning direction (Sx).
  • the light flux emitted from each light emitting source LED is collimated by a corresponding hood lens that is a convex lens and then collected by an illumination lens (3) that is a convex cylinder lens. Light and diverge.
  • the periphery of the imaging area (Ai) is more than the focal position (virtual light source position) of the convex cylinder lens disposed on the center line side of the imaging area (Ai).
  • the pair of light source LED, convex lens, and convex cylinder lens is placed so that the focal position (imaginary light source position) of the convex cylinder lens placed on the side is close to the imaging area (Ai). More specifically, the distance between the imaging area (Ai) and the focal position of the convex cylinder lens (the position of the virtual light source) is the relative brightness of the image formed on the one-dimensional CCD by the imaging lens. Is proportional and given by X cos 40 . In FIG. 30 (a), the number of light sources is 10
  • the number of light sources was set to 25.
  • FIG. 30 (b) only the combination of the light source, the convex lens, and the convex cylinder lens at the center and one end in the main scanning direction (Sx) is shown, and the other light source, convex lens, and The convex cylinder lens is omitted.
  • the light flux emitted from each light emitting source LED is converted into parallel light by a hood lens that is a convex lens corresponding to the LED.
  • the light passes through the illumination lens (3), which is a convex cylinder lens, as parallel light and is focused on the imaging area (imaging target area) (Ai) by the focusing lens (4a) (or focusing mirror).
  • the distance from the imaging area (Ai) to the light source varies between the central part and the peripheral part in the main scanning direction (Sx), but the distance from the focusing lens (4a) (or focusing mirror) to the imaging area (Ai) Since the distance to the light source is constant, the degree of focusing of the light emitted from the light emitting source LED does not vary depending on the position of the light source in the main scanning direction (Sx). In other words, in the sub-scanning direction (Sy), the distance from the illumination lens (3) to the focusing lens (4a) (or focusing mirror) fluctuates, but the luminous flux from the illumination lens (3) to the focusing lens (4a ) (Or focusing mirror) is parallel light.
  • the light beam is focused Since the distance from the focusing lens (4a) (or focusing mirror) to the imaging area (Ai) is constant, the degree of focusing of light does not vary. It is not always necessary to insert the focusing lens (4a) (or focusing mirror). That is, when taking into consideration the floating of the document, it is preferable not to use the focusing lens (4a) (or the focusing mirror). However, even in this case, the purpose of making the relative brightness of the image formed on the one-dimensional CCD constant is not impaired.
  • the illuminance distribution of light that illuminates the imaging target area (Ai) is adjusted to 1 / cos 4 ⁇ by adjusting the radiation characteristics of the light emitted from the plurality of light sources.
  • An example of matching is shown.
  • FIG. 32 is a diagram for explaining a specific arrangement of a plurality of light sources that illuminate the imaging target region so that the relative brightness of the image formed on the one-dimensional CCD is constant.
  • FIG. 32 (a) is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface on which the side mirror is arranged
  • FIG. 32 (b) is a diagram showing an example of the radiation characteristics of the light sources.
  • the symbols in FIG. 32 are the same as the symbols in FIG. 24.
  • the distance between the light sources in the main scanning direction (Sx) and the illumination target area (imaging target area) (Ai) The distance to is constant. That is, in FIG. 32 (a), the intervals wl, w2, ••• wnii of the plurality of light sources are constant and equal to Wh / N. In other words, the intervals wl, w2, ••• wntt of the plurality of light sources are given by dividing the half Wh of the length of the imaging target area (Ai) in the main scanning direction (Sx) into N equal parts.
  • the distance from each of the plurality of light sources to the illumination target area (imaging target area) (Ai) is L. However, it is emitted from each light source.
  • the light radiation characteristics are changed.
  • ⁇ is the center of the imaging lens and the area to be imaged with respect to the optical axis of the imaging lens.
  • the radiation characteristics of the light emitted from the light source arranged at the kth position P among the plurality of light sources are
  • R k T k 2 -cos B (k) a k
  • T 2 is emitted from the light source at the kth position P.
  • the intensity of the vector vector in the vertical direction with respect to the illumination target surface (imaging area) (Ai), and B (k) is the light emission emitted from the light source at the kth position P.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) irradiated with light emitted from a plurality of light sources is the same as in the twelfth embodiment of the present invention.
  • Position P force Because it is a virtual light source that is a mirror image of the light source up to position P, the light emission characteristics of the light source
  • the maximum value of the difference is about ⁇ 5%, which is slightly larger than the maximum value of the difference shown in the drawing (1) in FIG.
  • the maximum value of such a difference is almost a problem with regard to the accuracy of parts and assembly, as well as the power and displacement from the viewpoint of energy saving! /. (Even if you change the amplification factor of the electrical signal after converting the light quantity into an electrical signal with a one-dimensional CCD and correct the difference, the change in the amplification factor is hardly affected by the small noise. )
  • the illuminance distribution of the light that illuminates the imaging target area (Ai) is matched with the 1 / cos 4 ⁇ characteristics.
  • Figure 33 shows that the illuminance distribution of the light that illuminates the imaging area (imaging target area) matches the 1 / cos 4 ⁇ characteristics by adjusting the radiation characteristics of the light emitted from multiple light sources. It is a conceptual diagram for implement
  • FIG. 33 (a) is a top view thereof, and
  • FIG. 33 (b) is a front view thereof.
  • the focal lengths of the convex lenses corresponding to the plurality of light sources arranged in the main scanning direction (Sx) are constant and arranged in the main scanning direction (Sx).
  • Multiple light sources The focal length of the illumination lens (convex cylinder lens) (3) corresponding to is changed as shown in FIG.
  • the envelope of the radiation characteristic of the virtual light source formed at the focal position of the illumination lens is flat with strong dispersion as shown in Fig. 31 (2).
  • FIG. 33 (b) only the combination of the light source, the convex lens, and the convex cylinder lens at the center and one end in the main scanning direction (Sx) is shown, and the other light source, convex lens, and The convex cylinder lens is omitted.
  • the light flux emitted from each light emitting source LED is converted into parallel light by a hood lens that is a convex lens corresponding to the LED.
  • the light passes through the illumination lens (3), which is a convex cylinder lens, as parallel light, and is focused on the imaging area (Ai) by the focusing lens (4a) (or focusing mirror).
  • the focusing lens (4a) (or focusing mirror) force and imaging area ( Since the distance to Ai) is constant, the degree of focusing of the light emitted from the light source LED does not vary depending on the position of the light source in the main scanning direction (Sx). In other words, from the illumination lens to the focusing lens (4a) (or focusing mirror) in the sub-scanning direction (Sy). The distance from the illumination lens to the focusing lens (4a) (or the collecting mirror) is parallel light.
  • the degree of focusing of the light does not change. Note that it is not always necessary to insert the focusing lens (4a) (or the focusing mirror). That is, when taking into account the floating of the document, it is preferable not to use the focusing lens (4a) (or the focusing mirror). However, even in this case, the purpose of making the brightness of the image formed on the one-dimensional CCD constant is not impaired.
  • the fourteenth embodiment of the present invention shows an example of a concept of an illuminating device that approximates the illuminance distribution of light that illuminates the imaging region (imaging target region) (Ai) to the characteristic of 1 / cos 4 ⁇ .
  • Figure 34 shows that each force of multiple light sources is adjusted by adjusting the distance to the imaging area (Ai).
  • FIG. 5 is a conceptual diagram for realizing an illumination device that approximates the illuminance distribution of light that illuminates the imaging region (Ai) to the i / cos 4 e characteristic.
  • FIG. 34 (a) is a top view thereof, and FIG. 34 (b) is a front view thereof.
  • FIG. 34 (c) is a diagram showing an example of the illuminance distribution of the light illuminating the imaging area which is approximated to the characteristic of l / cos 4 6.
  • the illuminance distribution of the light that illuminates the imaging region (Ai) is 1 / cos.
  • the characteristics of the 4 theta has been described an example of a lighting device matching with good accuracy.
  • a configuration that can be manufactured more easily for example, by sacrificing the accuracy of the illuminance distribution of the light that illuminates the imaging area (Ai), which should have the characteristic of 1 / cos 4 ⁇ .
  • the illumination device according to the embodiment of the present invention shown in FIG. 34 can be more easily manufactured than the illumination device described in the twelfth embodiment of the present invention.
  • the difference between the ideal illumination distribution and the approximate illuminance distribution is the ideal cos 4 It is based on the difference between the position on the curve of ⁇ and the position on the side of the trapezoid of multiple light sources, and is very small.
  • Figure 34 (a) shows the trapezoidal characteristics of the target illuminance distribution of the light that illuminates the imaging area (Ai) by adjusting the distance to the imaging area (Ai) for each of the light sources.
  • the concept of the lighting device approximated by is shown.
  • the light source that gives the trapezoidal side characteristic parallel to the imaging area (Ai) in the trapezoidal characteristic is a light source or a virtual light source (here, an illumination lens (3 ) Is placed on a trapezoidal side parallel to the imaging area (Ai).
  • a light source that gives a characteristic of a side inclined with respect to the imaging region (Ai) in the trapezoidal characteristic is a light source or a virtual light source (here, the focal point of the illumination lens (3)), and the imaging region (Ai
  • the prism (7) is provided on the imaging region (Ai) side of the illumination lens (3) that is a cylinder lens.
  • the optical axis extending from the light source or the virtual light source is bent by the prism (7) by the prism (7) provided closer to the imaging area (Ai) than the illumination lens (3), and the bent optical axis becomes the imaging area. Be perpendicular to (Ai).
  • a flat plate can be used as the substrate for supporting the light source, which makes it easier to manufacture the lighting device.
  • a force S using a paraboloidal mirror is used to make the luminous flux emitted from the light source LED parallel light, and a shell-shaped hood lens is used. May be.
  • the relative position curve of multiple light sources, cos 4 ⁇ gives an ideal illumination distribution in the imaging area (Ai) with l / cos 4 e characteristics. Is divided into three in the range of the imaging region (Ai), but may be divided into two in the range of the imaging region (Ai) if the efficiency is sacrificed.
  • the curve of the relative position of the plurality of light sources may be approximated to a triangle whose vertex is a point on the curve at a position where the curve is divided into two.
  • the plurality of light sources are arranged only on the side inclined with respect to the imaging area (Ai). In this way, even if the relative position curve of the multiple light sources is approximated to a triangle by dividing into two in the range of the imaging area (Ai), compared with the case where the imaging area (Ai) is illuminated uniformly. The use efficiency of light emitted from the light source can be greatly improved.
  • a curve of the relative positions of multiple light sources that give the ideal illuminance distribution in (Ai) to a polygon within the range of the imaging area (Ai).
  • the approximate trapezoidal or triangular vertex position in the twelfth embodiment may be approximated to a trapezoidal or triangular shape having a vertex at a position opposite to the plane parallel to the imaging area (Ai).
  • a flat plate can be used as the substrate for supporting the light source, and the manufacture of the lighting device becomes easier.
  • the light source is a combination of red (R), green (G), and blue (B) LEDs
  • red light, green light Chromatic aberration occurs between blue light.
  • the red light, the green light, and the blue light that have passed through the plurality of prisms are superimposed on each other in the imaging region (Ai) to provide almost white light illumination to the imaging region (Ai). Become. Therefore, in practice, chromatic aberration due to the prism is rarely a problem.
  • Example 15 the imaging region is adjusted both by adjusting the distance from each of the plurality of light sources to the imaging region (Ai) and by adjusting the radiation characteristics of the light emitted from the plurality of light sources.
  • An example of matching the illuminance distribution of the light illuminating with the 1 / cos 4 ⁇ characteristic is shown.
  • FIG. 35 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) so that the relative brightness of an image formed on the one-dimensional CCD is constant.
  • FIG. 35 (a) is a diagram showing the arrangement of a plurality of light sources and the position of the mirror surface on which the side mirror is arranged
  • FIG. 35 (b) is a diagram showing an example of the radiation characteristics of the light sources.
  • the intervals between the plurality of light sources in the main scanning direction (Sx) are constant, but the illumination target region (imaging target region) (Ai) from each of the plurality of light sources And the radiation characteristics of light emitted from multiple light sources.
  • the meaning of the symbol in FIG. 35 is the same as the symbol in FIG. 24, and the intervals wl, w2, ⁇ ⁇ between the light sources are constant and equal to Wh / N.
  • the intervals wl, w2, •• wnii of a plurality of light sources are given by dividing the half Wh of the length of the imaging target area (Ai) in the main scanning direction (Sx) into N equal parts.
  • the shape factor b of B (k) in the equation is half the value of b in the thirteenth embodiment of the present invention.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) irradiated by the light emitted from the plurality of light sources is the twelfth aspect of the present invention.
  • the imaging target area (Ai) Since the position P force is also a virtual light source that is a mirror image of the light source up to position P, the imaging target area (Ai)
  • the imaging area (Ai) The illuminance distribution near both ends can be controlled to some extent.
  • the maximum value of the difference is about ⁇ 2.5%, which is smaller than the maximum value of the difference shown in the graphs (1) and (2) of FIG.
  • the difference is larger than the maximum value shown in FIG. 26, such a maximum difference is hardly a problem from the viewpoints of component accuracy, assembly accuracy, and energy saving. ! / once Even if the gain of the electrical signal after changing the light amount into an electrical signal with the original CCD is changed and the difference is corrected, the amount of change in the amplification rate is hardly affected by the noise.
  • the illuminance distribution of the light that illuminates the imaging region is 1 / cos by both adjusting the distance from each of the plurality of light sources to the imaging region and adjusting the radiation characteristics of the light emitted from the plurality of light sources. 4 Shows the concept of lighting equipment that matches the characteristics of ⁇ .
  • FIG. 36 illuminates the imaging area (Ai) by adjusting both the distance from each of the multiple light sources to the imaging area (Ai) and adjusting the radiation characteristics of the light emitted from the multiple light sources. It is a conceptual diagram for realizing an illumination device that matches the illuminance distribution of light with the 1 / cos 4 ⁇ characteristic.
  • FIG. 36 (a) is a top view thereof
  • FIG. 36 (b) is a front view thereof.
  • the focal lengths of the convex lenses corresponding to the plurality of light sources arranged in the main scanning direction (Sx) are constant and arranged in the main scanning direction (Sx).
  • the focal length of the illumination lens (convex cylinder lens) (3) corresponding to a plurality of light sources varies as shown in FIG.
  • the envelope of the radiation characteristics of the virtual light source formed at the focal position of the illumination lens is flat with strong dispersion as shown in Fig. 31 (2).
  • each light source can be arranged so that the distance from the position of each light source to the illumination target surface (imaging region) (Ai) is constant. of
  • a light source can be provided on a flat plate as a substrate. As a result, the lighting device can be more easily manufactured.
  • the simulation was performed with the number of light sources set to 25, in FIG. 36 (a), the number of light sources is shown as ten.
  • the light flux emitted from each light emitting source LED is flattened by a hood lens that is a convex lens corresponding to the LED.
  • the illumination lens which is a convex cylinder lens, as parallel light, and is focused on the imaging target area (Ai) by the focusing lens (4a) (or the focusing mirror).
  • the focusing lens (4a) or the focusing mirror.
  • the purpose of making the brightness of the image formed on the one-dimensional CCD constant is not impaired.
  • the illuminance distribution of the light that illuminates the imaging region by adjusting the angle of the illumination optical axis of the light emitted from the plurality of light sources has a characteristic of 1 / cos 4 ⁇ .
  • An example of matching is shown below.
  • FIG. 37 is a diagram illustrating a specific arrangement of a plurality of light sources that illuminate the imaging target area (Ai) such that the relative brightness of an image formed on the one-dimensional CCD is constant.
  • FIG. 37 corresponds to an enlarged view on the left side of the imaging target surface in FIG.
  • the symbols in Fig. 37 correspond to the symbols in Fig. 32.
  • the illumination distribution in the imaging target area (Ai) has the characteristic of 1 / cos 4 ⁇ . Adjust the angle of the illumination optical axis.
  • a mirror surface (side mirror) is placed at the position of the outside PM1.
  • This mirror surface is the object to be imaged It is placed on the light source placement position corresponding to the point where the range of area (Ai) is divided! / Reflects the light beam emitted from multiple light sources, and whether the light source is on the extension line In this way, the illumination target area (Ai) is illuminated.
  • it corresponds to the position of the dividing points P 1,.
  • the position of the virtual image (virtual light source VLS) obtained by the side mirror is P, P, ... n + 1 n + 2
  • the illumination optical axis of light that also emits force is tilted by an angle / 3 with respect to the vertical direction of the illumination target surface (imaging area) (Ai) (the angle of the optical axis of the light source at position P is / 3).
  • the angle / 3 of the illumination optical axis of the 00 00 k light source is directly connected from the point P00 to the position P of the light source.
  • the line is an angle formed with the center line CL of the imaging target area (Ai).
  • the angle is made with the center line CL of the imaging target area (Ai). That is, the angle of the illumination optical axis of the light source at the position P with respect to the center line CL of the imaging target area (Ai) is ⁇ .
  • the angle / 3 of the illumination optical axis with respect to the light source position P exceeding the angle / 3 increases as k increases.
  • the angle ⁇ 0 when P becomes P.
  • the optical axis of the light source of ⁇ located at an angle ⁇ or more should face the end of the imaging target area (Ai) up to ⁇ .
  • the mirror surface of the side mirror should be as close as possible to the light source at position ((until the side mirror as a plane mirror contacts the light source at position ⁇ Move the mirror closer to the light source at position Pn . ) I like it! /
  • a side mirror PM2 that forms a pair with a side mirror provided outside the light source at position P is also provided in the upper half area with respect to the center line of the imaging target area (Ai).
  • the side mirrors provided outside the light source are arranged in parallel to each other. For this reason, an infinite number of imaginary light sources, which are mirror images of the imaginary light source, are generated by the pair of side mirrors. It occurs at a distant position. For this reason, the contribution ratio of the mirror image of the imaginary light source to the illuminance distribution in the imaging target area (Ai) is extremely small and can be ignored.
  • the relative illuminance I (Mm) at an arbitrary point Mm in the imaging target area (Ai) illuminated by a plurality of light sources is determined. From the light source to the illumination target area (Ai), the vertical line to the illumination target area (imaging target area) (Ai) and the angle of the radiation vector of the emitted light directed to the point Mm from the light source is ⁇ . Since the distance force S and L0 of a single light source force, the distance to the point Mm is LO / cos a.
  • the point of the illumination target area (Ai) illuminated by the light emitted from each light source The intensity of light at Mm is inversely proportional to the distance LO / cos a from each light source to point Mm. Furthermore, the degree of decrease in the luminous flux due to the tilt of the surface at the same point Mm is cos a.
  • the intensity of light emitted from the light source in the direction of the radiation vector that forms an angle ⁇ with the vertical line with respect to the illumination target region (imaging target region) (Ai) Depends on the distribution (envelope) of the radiation vector of light emitted from.
  • the radiation distribution (envelope) of a light source such as an actual LED has a complex shape, but it is approximated by a circle or ellipse for convenience of calculation. For example, as shown in (1) of FIG.
  • the envelope of the radiation vector of the light emitted from the light source when the envelope of the radiation vector of the light emitted from the light source can be approximated to a circle, the direction of the radiation vector forming an angle ⁇ with respect to the illumination optical axis of the light source The intensity of light emitted from the light source is reduced by cos ⁇ .
  • the envelope of the radiation vector of the light emitted from the light source can be approximated to an ellipse, the light source is emitted in the direction of the radiation vector that forms an angle ⁇ with the vertical line with respect to the illumination target area (imaging target area) (Ai).
  • the degree of decrease in light intensity depends on the shape of the envelope of the radiation vector, cos 2 ⁇ as shown in Fig. 24 (2), and in Fig. 24 (3). It is possible to approximate such as cos 4 ⁇ as shown.
  • I (Mm) A k -cos 2 a k 'cos- k ) (but ⁇ k ⁇ )
  • A is the relative value of the total amount of light emitted by the kth light source.
  • ⁇ is the direction force at point Mm with respect to the vertical line of the illumination target area (Ai), and the radiation of the kth light source k
  • the angle of the vector. A is a coefficient approximating the envelope of the radiation vector of the light source.
  • a l
  • the envelope of the light source radiation vector is elliptical.
  • the light is emitted from the light source arranged at the position P.
  • the radiation vector of the light source that reaches the point Mm of the illumination target area (Ai) has a straight line angle ⁇ between the position P with respect to the vertical line of the illumination target area (Ai) and the point Mm.
  • the illumination optical axis of the light source placed at position P is tilted by 0 k with respect to the vertical line of the elephant area (Ai)
  • the illumination distribution over the entire area and the center line of the illumination target area (Ai) (over the entire illumination target area (Ai) illuminated by the whole light source placed in the upper half
  • the illuminance distribution over the entire area to be illuminated (Ai) illuminated by all the light sources can be obtained (however, if this calculation is performed, place it on P
  • the luminous flux emitted from the light source is the center line (used to calculate the lower half of the CU force and the upper half, so the relative intensity A of the light source is placed at other positions.
  • FIG. 38 is a diagram showing simulation results for the difference between the relative illuminance and the target illuminance distribution in the sixteenth practical example of the present invention.
  • the entire imaging target region (Ai) illuminated by the plurality of light sources is processed in the same manner as in the twelfth embodiment of the present invention.
  • the illuminance distribution over the area was obtained.
  • a graph similar to FIG. 25 was obtained.
  • FIG. 38 shows only an enlarged view of the difference between the illuminance distribution and the target illuminance distribution over the entire area to be imaged (Ai) illuminated by a plurality of light sources.
  • Figure 38 shows the difference between the obtained illuminance distribution and the target illuminance distribution at any position of the imaging target area (Ai), and the illuminance at the periphery of the imaging target area (Ai)
  • the illuminance at the end of the imaging target area (Ai) and the central part of the imaging target area (Ai) are almost the same.
  • the maximum value of the difference shown in the graph of Fig. 38 is slightly more than + 8% at a position 15% inside from the extreme end in the imaging target area (Ai).
  • the ratio of the amount of light discarded at the center of the imaging target area (Ai) is 23%, so the imaging target area (Ai) is illuminated uniformly.
  • the utilization efficiency of the light emitted from the light source can be greatly improved. If there is a difference of this level, change the amplification factor of the electric signal after converting the light amount into an electric signal with a one-dimensional CCD. Even if the difference is corrected, the rate of change in the amplification factor is hardly affected by the small noise.
  • Figure 39 shows that the illuminance distribution of the light that illuminates the imaging area (Ai) matches the 1 / cos 4 ⁇ characteristics by adjusting the angle of the illumination optical axis of the light emitted from multiple light sources. It is a conceptual diagram for implement
  • FIG. 39 (a) is a top view thereof, and
  • FIG. 39 (b) is a front view thereof.
  • the light source LED and the convex lens form a virtual light source as shown in FIG.
  • a means for inclining the illumination optical axis of the light source with respect to the center line of the illumination target area (imaging area) (Ai) as shown in FIG. 34, immediately after the illumination lens (3) of the convex cylinder lens Can be used.
  • the intervals between the plurality of light sources are equal, but also in the illumination device shown in FIG. 39, the intervals between the plurality of light sources themselves are equal.
  • the position of the virtual light source is displaced from the illumination optical axis of the light source while the illumination optical axis of the optical axis is inclined.
  • the straight line connecting the edges of Ai) increases as the position of the virtual light source is closer to the edges.
  • the distance between the virtual light sources included in the area outside the line becomes smaller as the position of the virtual light source is closer to the edge, so that the simulated lighting device shown in FIG. Strictly speaking, it is necessary to shift the position of the light source in response to the displacement of the position of the virtual light source.
  • the displacement of the position of the virtual light source is not a big problem.
  • the radiation characteristic of the illumination lens (3) inside the edge line EL is made relatively divergent, and the illuminance at the center of the imaging area (Ai) is relatively reduced, and the illumination lens ( The radiation characteristics of 3) are made relatively convergent, and the illuminance in the peripheral area of the imaging area (Ai) is relatively increased. As a result, the difference peak size shown in FIG. 38 can be reduced.
  • the force S can further reduce the size of the difference peak shown in FIG.
  • the light beam from the light source LED is made to be substantially parallel light, and then the convex cylinder lens is used only in the main scanning direction (Sx) with a convex cylinder lens. It has been explained that a virtual light source is formed by focusing once on the focal point. However, even if the convex cylinder lens is replaced with a concave cylinder lens, a virtual light source can be formed from the light source.
  • FIG. 40 is a diagram for explaining the formation of the virtual light source VLS from the light source using the concave cylinder lens.
  • 40 (a) is a top view of an optical system using a concave cylinder lens
  • FIG. 40 (b) is a front view of the optical system using a concave cylinder lens.
  • the light flux emitted from the light emitting light source LED is made to be approximately parallel light using a convex lens, and then can be diverged only by the concave cylinder lens in the main scanning direction (Sx). .
  • the position of the virtual light source with respect to the light source is formed at the focal point of the concave cylinder lens (focal length fl) as shown in FIG.
  • a concave cylinder lens By using a concave cylinder lens, a concave cylinder lens
  • the virtual light source VLS can be positioned closer to the light source side (when a convex cylinder lens is used, the virtual light source is formed on the imaging region (Ai) side than the concave cylinder lens). For this reason, the illumination device can be made smaller by appropriately selecting the focal length fl of the concave cylinder lens.
  • LED light emitting diode
  • a single light source such as red (R), green (G), blue (B), etc. alone is used as a light emitter.
  • a device such as a blue LED or a purple LED that emits a luminous flux to a phosphor to obtain white light can be applied to the apparatus of the present invention.
  • a neon tube, a discharge lamp such as a small high-pressure mercury lamp, or a small bulb-shaped filament bulb can be applied.
  • 41 and 42 are diagrams illustrating optical components that can be used in the embodiments and examples of the present invention.
  • FIG. 41 (a) is a diagram showing an example of the first cylinder lens array.
  • the first cylinder lens array as shown in FIG. 41 (a) is composed of a plurality of convex cylinder lenses arranged adjacent to each other, and is used as an illumination lens in the embodiments and examples of the present invention. obtain.
  • FIG. 41 (b) is a diagram showing an example of the second cylinder lens array.
  • the first cylinder lens array as shown in FIG. 41 (b) is composed of a plurality of concave cylinder lenses arranged adjacent to each other, and is used as an illumination lens in the embodiments and examples of the present invention. obtain.
  • FIG. 41 (c) is a diagram showing an example of the first cylinder lens.
  • the first cylinder lens as shown in FIG. 41 (c) has a plano-convex cross section, and can be used as a focusing lens in the embodiments and examples of the present invention.
  • FIG. 41 (d) is a diagram showing an example of the second cylinder lens.
  • the second cylinder lens as shown in FIG. 41 (d) has a biconvex cross section, and can be used as a focusing lens in the embodiments and examples of the present invention.
  • Fig. 41 (e) is a diagram showing an example of a parabolic mirror or an ellipsoidal mirror.
  • a parabolic mirror or ellipsoidal mirror as shown in Fig. 41 (e) has a parabolic or elliptical cross section in one direction and a parallel plane in a direction perpendicular to that direction. It is a mirror which has the cross section.
  • a parabolic mirror or ellipsoidal mirror as shown in Fig. 41 (e) can be easily formed using a bright aluminum thin plate, so a parabolic mirror or ellipse as shown in Fig. 41 (e) is used. The cost for manufacturing the surface mirror can be reduced.
  • FIG. 41 (f) is a diagram showing an example of a plane mirror.
  • a plane mirror as shown in FIG. 41 (f) can be used as a turning mirror and a folding mirror in the embodiments and examples of the present invention.
  • the plane mirror as shown in FIG. 41 (f) is used as a turning mirror, in order to reflect light with image information, the plane mirror as shown in FIG. A plane mirror having one surface as a mirror surface is preferable.
  • the plane mirror as shown in FIG. 41 (f) is a plane mirror manufactured using a bright aluminum plate V. Moyore.
  • FIG. 42 (a) is a diagram showing a convex cylinder lens.
  • a convex cylinder lens as shown in FIG. 42 (a) can be used as an illumination lens in the embodiments and examples of the present invention.
  • FIG. 42 (b) is a diagram showing a concave cylinder lens.
  • a concave cylinder lens as shown in FIG. 42 (a) can be used as an illumination lens in the embodiments and examples of the present invention.
  • FIG. 42 (c) is a diagram showing a prism.
  • a prism as shown in FIG. 42 (c) can be used as an optical element that bends (deflects) the illumination optical axis in the embodiments and examples of the present invention.

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Abstract

La présente invention concerne un procédé et un dispositif d'éclairage de document destinés à éclairer un document avec une efficacité supérieure au moyen d'une lumière émise par une source de lumière. Le procédé destiné à éclairer un document avec une lumière émise par une source de lumière comprend une étape qui consiste à éclairer un document avec de la lumière produite par combinaison de lumières émises par des sources de lumières agencées au moins dans une première direction, et une étape qui consiste à diffuser les faisceaux lumineux émis par les sources de lumière de sorte que chacun d'eux est diffusé dans un faisceau lumineux ayant une largeur qui vaut au moins deux fois l'intervalle entre des sources de lumières adjacentes dans la première direction. Le dispositif d'éclairage de document destiné à éclairer un document avec une lumière émise par une source de lumière comprend des sources de lumière agencées au moins dans une première direction, et un système optique destiné à combiner les lumières émises par les sources de lumière, éclairer le document avec la lumière combinée, et diffuser chacun des faisceaux lumineux émis par les sources de lumière vers un faisceau lumineux ayant une largeur qui vaut au moins deux fois l'intervalle entre des sources de lumière adjacentes dans la première direction.
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JP2005156600A (ja) * 2003-11-20 2005-06-16 Ricoh Co Ltd 照明装置、画像読取装置及び画像形成装置
JP2006017951A (ja) * 2004-06-30 2006-01-19 Ricoh Co Ltd 原稿照明装置、画像読取り装置、および画像形成装置

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JP2010219600A (ja) * 2009-03-13 2010-09-30 Ricoh Co Ltd 照明装置、画像読取装置及び画像形成装置
JP2010268221A (ja) * 2009-05-14 2010-11-25 Sharp Corp 照明装置、画像読取装置及び画像形成装置
JP2011114762A (ja) * 2009-11-30 2011-06-09 Kyocera Mita Corp 画像読取装置及びこれを備えた画像形成装置

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