JP2004040149A - Illuminator and image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus for reading a transparent original which gives a high-quality read image from which dust or scratch is removed. <P>SOLUTION: In the image reading apparatus for reading the transparent original, a transparent original illumination unit has a first and second surfaces on the same side portion. On the first surface, at least one light source for emitting light in at least a visible range is arranged. On the second surface, at least one light source including a plurality of infrared light sources arrayed in series to emit light in an infrared range is arranged. The first and second surfaces are arranged at positions different from an effective light-emitting region, and include a light guide plate and a reflecting sheet for substantially uniformly shining the entire surface with incident light from the same side portion. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an image reading apparatus that reads image information of an original such as a photographic film, and an illumination device used for the image reading apparatus.
[0002]
[Prior art]
In a conventional image reading apparatus that reads image information of a transparent original such as a photographic film, if there is dust or the like on the transparent original or if there is damage (scratch) on the film surface, even if the dust or scratch is present, Is read, so that deterioration of the image due to dust or scratches cannot be prevented. In order to solve this problem, there has been proposed an image reading apparatus that corrects image information using a visible light source with information on dust and scratches obtained from image information using an infrared light source (Japanese Patent Application Laid-Open No. 2001-298593). In this image reading apparatus, a visible light source, which is a planar light source such as a fluorescent lamp, and a point-like infrared light source, such as an infrared LED chip, are arranged on the side surface of the light guide plate.
[0003]
[Problems to be solved by the invention]
However, in the above-described configuration of the conventional image reading apparatus, when each light source emits light, even if the visible light source is uniformly guided on the effective light emitting area surface by the light guide, the infrared light source is not emitted from the effective light emitting area. However, the light cannot be sufficiently diffused, and the irradiation light of the document becomes non-uniform, so that information on dust and scratches cannot be obtained accurately.
[0004]
[Means for Solving the Problems]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a lighting device according to claim 1 has a first light source that emits light in a visible region and a second light source that emits light in an invisible region. And a light guide plate for guiding and illuminating the light emitted from the first and second light sources in a planar manner, and arranging the first light source from an effective light emitting area of the light guide plate. , And a distance from the effective light emitting area to the arrangement portion of the second light source.
[0005]
The lighting device according to claim 11, wherein the first light source that emits light in a visible region, the second light source that emits light in an invisible region, and light emitted from the first and second light sources. A light guide plate for guiding and illuminating the light source in a planar shape, and a first reflection surface for reflecting the irradiation light of the second light source toward the inside of the light guide plate on the arrangement portion of the second light source. It is characterized by having been provided.
[0006]
The lighting device according to claim 19, further comprising: a first light source that emits light in a visible region, a second light source that emits light in an invisible region, and light emitted from the first and second light sources. A light guide plate for guiding and illuminating the light source in a planar shape, and arranging the first and second light sources in parallel along one side of the light guide plate; A reflection surface is provided between the second light source and the arrangement portion.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
(First form)
An image reading apparatus according to an embodiment of the present invention will be described with reference to the drawings.
[0008]
FIG. 1 is a block diagram showing the internal configuration of the image reading apparatus according to the present embodiment. The image reading device 1 is connected to the host computer 21 via a signal cable. The image reading device 1 operates according to a command from the host computer 21 to read an image and transfers an image signal to the host computer 21.
[0009]
Reference numeral 105 denotes an imaging lens for forming an image of the light emitted from the light source 3 from the original on a CCD 106 which is a solid-state imaging device. Reference numeral 24 denotes a light source lighting circuit for lighting the light source 3. Note that a CMOS or the like other than the CCD may be used as the image sensor. Next, in the electric board 116, a motor drive circuit 25 drives the pulse motor 126, and an excitation switching signal of the pulse motor 126 based on a signal from a system controller 26 which is a system control unit of the image reading device (image scanner) 1. Is output. 27R, 27G, and 27B are analog gain adjusters that variably amplify the analog image signal output from the CCD line sensor 106.
[0010]
Reference numeral 28 denotes an A / D converter, which converts an analog image signal output from the analog gain adjusters 27R, G, and B into a digital image signal. Reference numeral 29 denotes an image processing unit, which performs offset correction, shading correction, digital gain adjustment, color balance adjustment, masking, resolution conversion in the main and sub scanning directions, and dust / flaw correction processing to be described later on the digitalized image signal. Image processing. A line buffer 30 temporarily stores image data, and is realized by a general-purpose random access memory.
[0011]
An interface unit 31 communicates with the host 21. Here, the interface is realized by a SCSI controller, but another interface such as Centronics or USB may be adopted. An offset RAM 32 is used as a working area when performing image processing. Since the line sensors 106 are arranged in parallel with the RGB line sensors with a predetermined offset, the offset RAM 32 is used for correcting the offset between the RGB lines. The offset RAM 32 also temporarily stores various data such as shading correction. Here, it is realized by a general-purpose random access memory.
A gamma RAM 33 stores a gamma curve and performs gamma correction. A system controller 26 stores a sequence of the entire scanner as a program, and performs various controls in accordance with an instruction from the host 21. A system bus 34 connects the system controller 26 with the image processing unit 29, the line buffer 30, the interface unit 31, the offset RAM 32, and the gamma RAM 33, and includes an address bus and a data bus.
[0012]
Next, FIG. 2 is a schematic perspective view of the image reading apparatus of the present embodiment. As shown in FIG. 2, when reading a transparent original such as a developer photographic film, a transparent illumination unit 2 for illuminating the transparent original is rotatably attached to the image reading device 1 by a hinge portion 18. I have. The transmissive illumination unit 2 is attached with a planar light source 3, which will be described later, fixed on a unit lower cover 5 with screws or the like. The planar light source 3 is protected by a transparent light source protection member.
[0013]
A platen glass 13 for placing a document to be read is provided on the main body of the image reading apparatus 1. When reading a photographic film, the light shielding sheet 4 is placed on the platen glass 13. A shading window 4a provided on the light shielding sheet 4 is a window for measuring shading, and a transparent original placing portion 4b is a place where a transparent original is placed.
[0014]
FIG. 3 is a schematic perspective view showing a state of reading a transparent original illuminated by the transmission illumination unit, and FIG. 4 is a plan view of the planar light source 3. The planar light source 3 includes a light guide plate 19, a transmissive original reading lamp 6 such as a fluorescent lamp and a xenon lamp that irradiates light mainly in the visible region, and a dust detection lamp mainly composed of an LED having a light emission intensity only in the infrared region. 7 is comprised.
[0015]
The transparent document reading lamp 6 is installed on an end surface at a position L1 away from an end of an effective light emitting area for the planar light source 3 to illuminate the transparent document in a planar manner. It is installed on an end face located at a position L2 away from the end of the effective light emitting area. Here, the distance L2 at which the lamp 7 is disposed is set to be longer than the distance L1 at which the lamp 6 is disposed.
[0016]
The light guide plate 19 includes a light guide unit 11 that guides the illumination light L in a two-dimensional longitudinal direction by internal reflection, and a reflection system that reflects the light guided by the light guide unit 11 and reflects the light toward the document. A diffusion panel made of resin, comprising a sheet portion 10 and a diffusion sheet portion 12 for equalizing the light reflected by the reflection sheet portion 10. In the light guide section 11, a light guide pattern 121 is formed by a plurality of grooves so as to guide incident light in a substantially planar shape and emit light.
[0017]
As shown in FIG. 5, the reflection sheet section 10 is provided along the outer surface of the light guide section 11, and furthermore, the end of the reflection sheet section 10 covering the light guide light emitting surface side is formed as a transparent original image. By extending the area to the vicinity of the effective light emitting area to irradiate the area, the direct light of the transmissive original reading lamp 6 and the dust / flaw detecting lamp 7 is prevented from directly irradiating the image reading area, so that the light guide 19 is more uniformly formed. It is possible to emit light in a planar manner as a whole.
[0018]
In the present embodiment, the reflection sheet 10 is provided not only on the outer surface of the light guide 11 but also between the arrangement portion of the transmissive original reading lamp 6 and the arrangement portion of the dust scratch detection lamp 7. It is possible to efficiently guide the infrared light illuminated from the lamp 7 to the inside of the light guide 11 in the longitudinal direction. Instead of arranging the reflection sheet, a reflection paint may be applied or printed. The light L emitted from the transmissive original reading lamp 6 and the dust flaw detection lamp 7 is reflected two-dimensionally between the reflection sheet unit 10 and the diffusion sheet unit 12 to pass through the light guide unit 11 two-dimensionally. Go in the longitudinal direction. Then, part of the light incident on the diffusion sheet portion 12 is diffused, and the entire light guide plate 19 emits light uniformly in a plane.
[0019]
Here, the dust flaw detection lamp 7 includes a plurality of infrared LED chips 7a and an LED substrate 7b having a light emitting opening 7c at a position corresponding to the infrared LED chips 7a. The infrared LED chip 7a is arranged such that the light emitting portion of the infrared LED chip 7a is located inside the LED opening 7c of the LED substrate 7b from the side opposite to the light guide facing surface of the LED substrate 7b. The chip 7a is arranged. The light guide body facing surface of the LED substrate 7b is formed flat, forms a reflective surface by applying or printing a white paint, and directs light emitted from the LED chip 7a to the inside of the light guide unit 7. It is possible to efficiently reflect light and improve the infrared luminance of the entire surface light source 3. The dust flaw detection lamp 7 is fixed in a state in which it is in close contact with the end face of the light guide section 11 by being covered with the reflection sheet section 10, and efficiently guides the infrared light emitted from the dust flaw detection lamp 7. It is possible to guide inside the light body.
[0020]
The lamp 6 for illuminating the transmission original may emit light only in the visible region. However, if the lamp 6 mainly emits light in the visible region, it emits light in the invisible region such as the infrared region. May be. Further, the dust flaw detection lamp 7 does not need to emit only light in the infrared region, but may be any lamp that mainly emits light in the infrared region. Further, a light source other than a fluorescent lamp, a xenon lamp, and an LED may be used. As shown in FIG. 6, the reflective sheet portion 10 does not have to be provided between the transparent document reading lamp 6 and the LED substrate 7 of the dust / flaw detecting light source 6, and the manufacturing cost is reduced as compared with the case where it is provided. Can be lowered.
[0021]
FIG. 7 is a cross-sectional view of the image reading device of the present embodiment. The carriage 9 provided in the image reading apparatus 1 is equipped with a reflection original illumination lamp 20, a CCD line sensor 106, a lens 105, and a reflection mirror 16 respectively. The CCD line sensor 106 converts an image into an electric image signal, and has a plurality of image sensors arranged in a straight line. The carriage 9 is fitted with the carriage guide shaft 8, and is movable in the sub-scanning direction.
[0022]
Next, the operation of reading a transparent original will be described. First, the reflecting document illumination lamp 20 and dust / flaw detection lamp 7 are turned off, and the transmissive document lamp 6 is turned on, so that the entire planar light source 3 emits light and the carriage 9 is moved in the sub-scanning direction. Image information on the transparent original is projected onto the CCD 106 via the reflection mirror 16 and the lens 105.
[0023]
Subsequently, the illumination lamp 20 for the reflection original and the illumination lamp 6 for the transmission original are turned off, and the lamp 7 for dust detection is turned on, so that the entire surface light source 3 emits light and the carriage 9 is moved in the sub-scanning direction. Dust, flaws and the like on the transparent original are projected onto the CCD 106 via the reflection mirror 16 and the lens 105. Here, since the light from the dust / flaw detection lamp 7 has only an infrared component, a transparent original such as a negative or a positive transmits the infrared component regardless of the image (photosensitive image), and dust that physically blocks the optical path. Since an image such as dust, scratches and the like is projected as a shadow on the CCD 14, dust and scratches can be detected satisfactorily.
[0024]
By performing image processing (dust / flaw correction processing) on both the dust / flaw detection image obtained in this way and the above-described transparent original read image in the image processing unit 29, a defect area due to dust and flaws recognized on the dust / flaw detection image is obtained. On the other hand, by interpolating from the surrounding original reading image, it is possible to read a good transparent original image from which the influence of dust and scratches has been removed.
[0025]
(Second form)
FIG. 8 is a sectional view of an image reading apparatus according to another embodiment of the present invention. An LED substrate 7b having a side surface height of the light guide section 11 is provided, and a reflection sheet 10b is provided on the side of the transparent document irradiation lamp 6 side. With this configuration, it is possible to improve the workability when mounting the infrared LED chip 7a on the LED board 7b, improve the strength of the LED board 7b, and improve the brightness of the light emitted by the transmissive document irradiation lamp 6.
[0026]
【The invention's effect】
As described above, according to the present invention, in an image reading apparatus using a planar light source, a good read image free of dust and scratches can be obtained.
[Brief description of the drawings]
FIG. 1 is a configuration block diagram of an image reading apparatus according to an embodiment.
FIG. 2 is a schematic perspective view of the image reading apparatus according to the embodiment.
FIG. 3 is a schematic perspective view of a transmission illumination unit according to the embodiment.
FIG. 4 is a schematic plan view of the transmitted illumination unit according to the embodiment.
FIG. 5 is a schematic sectional view of the image reading apparatus according to the embodiment.
FIG. 6 is a schematic sectional view of the image reading apparatus according to the embodiment.
FIG. 7 is a schematic sectional view of a transmission illumination unit according to the embodiment.
FIG. 8 is a schematic sectional view of the image reading apparatus according to the embodiment.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 image reading apparatus 2 transmission illumination unit 3 planar light source 4 light shielding sheet 6 lamp for illuminating transmitted document 7 dust detection lamp 7a infrared LED chip 7b LED board 7c light emission opening 10 reflection sheet 11 light guide 12 Diffusion sheet 19 Light guide plate 20 Reflector original light source 106 CCD line sensor 121 Light guide pattern

Claims (24)

A first light source that emits light in the visible region;
A second light source that emits light in an invisible region;
A light guide plate for guiding and illuminating the light emitted from the first and second light sources in a planar shape,
A lighting device, wherein a distance from an effective light-emitting area of the light guide plate to an arrangement portion of the first light source is different from a distance from the effective light-emitting area to an arrangement portion of the second light source. 2. The lighting device according to claim 1, wherein a distance from the effective light emitting area to the second light source arrangement part is longer than a distance from the effective light emission area to the first light source arrangement part. 3. . 3. The illumination according to claim 1, wherein a first reflection surface that reflects irradiation light of the second light source toward the inside of the light guide plate is provided in an arrangement portion of the second light source. 4. apparatus. The lighting device according to any one of claims 1 to 3, wherein the first and second light sources are arranged in parallel along one side of the light guide plate. The lighting device according to claim 4, wherein a second reflection surface is provided between the arrangement portion of the first light source and the arrangement portion of the second light source. The lighting device according to any one of claims 1 to 5, wherein the second light source emits light in an infrared region. 7. An illumination device according to claim 1, further comprising: reading means for converting light from a document illuminated by light from the illumination device into an image sensor to convert the light into an image signal. Characteristic image reading device. From the light guide plate to the image sensor based on an image signal obtained by causing light from the document illuminated by light from the second light source guided by the light guide plate to enter the image sensor. 8. The image reading apparatus according to claim 7, further comprising defect information reading means for reading defect information existing on the optical path. 9. The image reading apparatus according to claim 8, further comprising a correction unit that removes the defect information read by the defect information reading unit from the image information read by the reading unit. 10. The defect information according to claim 8, wherein the defect information is information generated by dust or scratches present on the original document blocking light from the second light source guided by the light guide plate. 5. The image reading device according to claim 1. A first light source that emits light in the visible region;
A second light source that emits light in an invisible region;
A light guide plate for guiding and illuminating the light emitted from the first and second light sources in a planar shape,
A lighting device, wherein a first reflection surface for reflecting irradiation light of the second light source toward the inside of the light guide plate is provided in an arrangement portion of the second light source. The lighting device according to claim 11, wherein the first and second light sources are arranged in parallel along one side of the light guide plate. 13. The lighting device according to claim 11, wherein a second reflecting surface is provided between the arrangement portion of the first light source and the arrangement portion of the second light source. 14. The lighting device according to claim 11, wherein the second light source emits light in an infrared region. 15. An illumination device according to claim 11, further comprising: reading means for causing light from a document illuminated by light from the illumination device to be incident on an image sensor and to convert the light into an image signal. Characteristic image reading device. From the light guide plate to the image sensor based on an image signal obtained by causing light from the document illuminated by light from the second light source guided by the light guide plate to enter the image sensor. 16. The image reading apparatus according to claim 15, further comprising defect information reading means for reading defect information existing on the optical path. 17. The image reading apparatus according to claim 16, further comprising a correction unit configured to remove the defect information read by the defect information reading unit from the image information read by the reading unit. 18. The defect information according to claim 16, wherein the defect information is information generated by dust or flaws present in the original document blocking light from the second light source guided by the light guide plate. 5. The image reading device according to claim 1. A first light source that emits light in the visible region;
A second light source that emits light in an invisible region;
A light guide plate for guiding and illuminating the light emitted from the first and second light sources in a planar shape,
The first and second light sources are arranged in parallel along one side of the light guide plate, and a reflection surface is provided between the arrangement portion of the first light source and the arrangement portion of the second light source. A lighting device, comprising: The lighting device according to claim 19, wherein the second light source emits light in an infrared region. 21. An image reading apparatus comprising: the illumination device according to claim 19; and reading means for converting light from a document illuminated by light from the illumination device into an image sensor and converting the light into an image signal. apparatus. From the light guide plate to the image sensor based on an image signal obtained by causing light from the document illuminated by light from the second light source guided by the light guide plate to enter the image sensor. 8. The image reading apparatus according to claim 7, further comprising defect information reading means for reading defect information existing on the optical path. 23. The image reading apparatus according to claim 22, further comprising a correction unit configured to remove the defect information read by the defect information reading unit from the image information read by the reading unit. 24. The defect information according to claim 22, wherein the defect information is information generated by dust or scratches present on the document itself blocking light from the second light source guided by the light guide plate. 5. The image reading device according to claim 1.

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