JPH10190963A - Image reader - Google Patents

Abstract

PROBLEM TO BE SOLVED: To turn a stable surface light source at a low cost to a light source and to provide the linear light source of sufficient luminance by a light convergence effect by a waveguide plate by providing the light source for performing surface light emission and a light-transmitting body for guiding a luminous flux emitted from the light source, irradiating from the end face of the light-emitting body and almost linearly illuminating a transmission original surface. SOLUTION: As a linear light source 4, an electroluminescence(EL) 6 which is a surface light source and the waveguide plate 7, which is the light-transmitting body are jointed and the light-emitting surface of the EL 6 is tightly adhered to the certain surface of the waveguide plate 7 formed by a transparent material. The end part of the waveguide plate 7 is turned into the linear light source, provided with a width for the thickness of the waveguide plate 7 and in a length equal to one side of the waveguide plate 7. That is, the luminous fluxes for emitting light in a wide area though light quantity is low are gathered by the waveguide plate 7 and radiated from a certain end face of the waveguide plate 7 as the thin and long linear light source by the light source 4. Then, a region on a linearly illuminated film is image- formed on a line CCD 2 by an image-forming lens 3 and taken out as one-dimensional image signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image reading apparatus, and more particularly, to illuminating image information of a document such as a film or an OHP using an image pickup means (reading means) in which a plurality of light receiving elements such as CCDs are arranged in a one-dimensional direction. TECHNICAL FIELD The present invention relates to an image reading device that reads light with high accuracy while improving light use efficiency.

[0002]

2. Description of the Related Art Conventionally, a film scanner has been widely known as an image reading apparatus for reading a transmission type original such as a film or an OHP using a reading means of a photoelectric conversion element such as a CCD.

Conventionally, in such an image reading apparatus,
What has been used as a light source is an LED, a small fluorescent tube, a xenon lamp, or the like. One of those used as a light source is a tubular fluorescent lamp. The fluorescent lamp, which is a light source, is a linear light source whose light emitting surface itself has a longitudinal direction and a lateral direction. A film, which is a transparent original, is disposed at a position where the film is illuminated by the light beam from the light source. An imaging lens system is further followed by a photoelectric conversion element such as a CCD as a line sensor at a focal position of the imaging lens system.

The image of the area on the document illuminated by the light source is formed on a CCD by an image forming lens. The shape of the light receiving area of the CCD is such that light receiving pixels are usually arranged in a straight line in a line. Therefore, a portion on the document when the image of the light receiving area of the CCD is back-projected onto the document by the imaging lens is a one-dimensional image area captured by the CCD at that time.

In this manner, a certain one-dimensional area on the document (a line image, more precisely, a strip-shaped area having a certain width, in which the CCD light receiving area is back-projected onto the document surface).
Immediately after the image has been captured, the capturing area is sequentially moved in a direction orthogonal to the line image to capture a one-dimensional image, and the same operation is repeated over a predetermined area on the document, thereby covering the entire surface of the document in two dimensions. Can be captured as an image.

In another illumination system, for example, as shown in Japanese Patent Laid-Open Publication No. 7-283907, an LED array in which 5 to 6 LED chips are arranged in an array is made to emit light, and this light beam is emitted. There is also an example in which a linear light beam is formed by using a long toric mirror or the like to illuminate the one-dimensional image area.

As described above, such an image reading apparatus requires an illumination system of a linear light beam for effectively illuminating a one-dimensional image area on the original.

[0008]

A problem with such conventional light sources is that of cost.

[0009] In the LED light source used in the conventional example, the price of the light source itself is low for red light, but the price increases as the light source becomes green and blue. Further, since the lighting circuit is a low-current power supply, the circuit device for lighting is inexpensive.
As shown in JP-A-283907, an optical component such as a condensing means (prism) and a toric mirror are required.

[0010] Further, the type using a fluorescent tube has a problem that the price of the lamp and the lighting circuit is high. In general, since a fluorescent lamp is a white light source, an expensive three-line CCD with a color filter has to be used. On the other hand, if three fluorescent tubes that emit each color of RGB are used by selecting the fluorescent material, the CCD can be one line, but the same reading area on the original is substantially the same for each of the three fluorescent tubes. Although it is necessary to illuminate with such an illuminance, it is difficult to arrange the fluorescent tubes in close proximity due to their large size, and the distance between the document and the lamp tends to be large. For this reason, there is also an adverse effect such as a decrease in the amount of illumination light, which is very difficult.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to improve the structure of a conventional image reading apparatus comprising a light source, an image forming optical system, and a CCD or the like. (Electroluminescence) element,
The light flux is taken in from the surface of the light guide in the opposite arrangement of the light guide,
The light guide is propagated, and a light beam is extracted from one end face of the light guide as a linear light source.

More specifically, the present invention relates to an image reading apparatus provided with a light source for illuminating a part on the surface of a transmissive original, wherein the light source emits a surface light and a light guide for guiding a light beam emitted from the light source. And irradiates the light from the end face of the light guide, and as a result, illuminates the transmissive document surface in a substantially one-dimensional manner. An image reading apparatus including a light source for illuminating a part of a transmission type document surface and a photoelectric conversion element for receiving light transmitted from the light source, comprising: a light source for surface light emission; and a light beam emitted from the light source. A light guide, the light guide having a high-reflection coating on a surface facing the surface light source, and radiating from the end surface of the light guide. Illuminating the light. The image reading apparatus further includes a light source that illuminates a part of the surface of the transmissive original, and a photoelectric conversion element that receives the transmitted light from the light source, wherein the light source emits a surface light and a light flux emitted from the light source is guided. A light guide, the light guide having a high-reflection coating on all end faces other than the face facing the surface light source and the end face from which the light flux is taken out, and radiating from the end face of the light guide, As a result, the document surface is illuminated substantially one-dimensionally.

Further, the present invention is an image reading apparatus comprising a light source for illuminating a part on the surface of a transmissive original and a photoelectric conversion element for receiving the transmitted light from the light source. A light guide that is disposed between the two surface light sources and guides a light beam emitted from the two surface light sources from both sides, and emits the light from the end face of the light guide toward the transmissive original. As a result, the document surface is illuminated substantially one-dimensionally. An image reading apparatus comprising: a light source for illuminating a part of a transmission type document surface; and a photoelectric conversion element for receiving light transmitted from the light source, wherein the light source emits two surfaces and a light beam emitted from the light source. A light guide that guides the light from both sides, the light guide having a high reflection coating on all the end faces other than the face on which the light flux is taken out and the end face on the transmission type original side, and the light guide The light is radiated from the end face on the side of the transmissive original, and as a result, the surface of the original is illuminated substantially one-dimensionally. The image reading apparatus further includes a light source that illuminates a part of the surface of the transmissive original, and a photoelectric conversion element that receives the transmitted light from the light source. A light guide, and a high-reflection coating provided on the surface of the light guide facing the surface light source. The end face to be formed is given a predetermined shape, and as a result, the emitted light beam has a uniform distribution in the linear direction of the emitting end face, and illuminates the document surface substantially one-dimensionally.

Further, the present invention relates to an image reading apparatus comprising a light source for illuminating a part on the surface of a transmissive original and a photoelectric conversion element for receiving transmitted light from the light source. A light guide that guides a light beam emitted from the two surface light sources from both sides, radiates from the end face of the light guide, and gives a predetermined shape to an end face opposite to the radiating end face, The resulting luminous flux has a uniform distribution and illuminates the document surface in a substantially one-dimensional shape. Also, an image reading apparatus including a light source that illuminates a part of a transmission type document surface and a photoelectric conversion element that receives transmitted light from the light source, the surface reading light source performing surface emission, and the surface emission light source includes: A light guide that guides the emitted light beam, and a high-reflection coat on a surface of the light guide that faces the surface light source, radiates from an end surface of the light guide, and the surface light source has a predetermined shape. As a result, the emitted light flux has a uniform distribution and illuminates the document surface in a substantially one-dimensional shape.

Further, the present invention is a light source device for illuminating a part of a document surface, comprising a linear light source for guiding a light beam emitted from two surface light sources from both sides of a light guide, Irradiating from the end face of the light guide, giving the two surface emitting light sources a predetermined shape, the resulting luminous flux has a uniform distribution,
It is characterized in that the document surface is illuminated substantially one-dimensionally. A light source device for illuminating a part of the original surface, the light source device comprising a linear light source for guiding light beams emitted from three surface light sources from both sides of the light guide; The other is provided with two surface-emitting light sources, the three types of surface-emitting light sources emit different colors, and the three types of surface-emitting light sources can be turned on independently of each other, and radiate from the end face of the light guide. As a result, the emitted light beam illuminates the surface of the document substantially one-dimensionally. Further, a light source device that illuminates a part of the original surface, the light source device includes a linear light source that guides a light flux emitted from a surface emitting light source with a light guide, and radiates from an end face of the light guide,
As a result, the surface of the transparent original is illuminated substantially one-dimensionally. The light source device illuminates a part of the original surface, and includes a linear light source that guides a light flux emitted from a surface-emitting light source by a light guide, and the light guide faces the surface-emitting light source. A high reflection coating is provided on the surface to be illuminated, and the light is radiated from the end surface of the light guide, and as a result, the surface of the document is illuminated substantially one-dimensionally.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

[First Embodiment] FIG. 1 is a conceptual diagram of a film scanner according to a first embodiment of the present invention.

In an image reading apparatus such as a film scanner for reading an image of a transparent document, the illumination light source is located at a position opposed to the image forming optical system with the transparent document interposed therebetween, so that there is no local interference. Therefore, the light source can be brought as close as possible to the read area on the document depending on the device.

In this embodiment, a linear light source 4 is formed by joining an EL 6 as a surface light source and a waveguide plate 7 as a light guide, and is made of a transparent material. The light-emitting surface of EL6 is adhered to the surface with 7. EL6 and waveguide 7
The coupling plate has a waveguide plate 7 as shown in FIG.
The side is processed to have a sawtooth-shaped cross section, and EL
The luminous flux having emitted 6 easily couples into the waveguide plate 7 and has a function of directing the light beam direction toward the exit surface on the film side.

A part of the light beam coupled in the large area is transmitted through the waveguide plate 7, but the other components propagate while being totally reflected in the waveguide plate 7, It reaches the end (lower part of FIG. 1). The end of the waveguide plate 7 has a width corresponding to the thickness of the waveguide plate 7 and becomes a linear light source having a length equal to one side of the waveguide plate 7 as shown in the figure. That is, although the light amount is low, a light beam emitted in a wide area is gathered by the waveguide plate 7 and emitted from one end face of the waveguide plate 7 as an elongated linear light source by the light source 4.

As shown in the figure, the end face of the waveguide plate 7 is arranged near the surface of the reading film 1, and the light beam extracted linearly illuminates the film surface linearly. The area on the film which is illuminated in a linear manner is line C by the imaging lens 3.
An image is formed on the CD 2 and extracted as a one-dimensional image signal. Then, the film 1 is sequentially moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main scanning direction), and
The information of the entire screen of the two-dimensional transparent original film is captured.
The emission of EL6 is prescribed to be white, and color reading is possible using a three-line CCD2. The movement of the light source 4, the imaging lens, and the CCD with respect to the transmission type film 1 is as follows.
It is sufficient to correspond to each other, and the latter may be moved. Also,
EL6 is a self-luminous type light source. An EL luminous body such as a phosphor is sandwiched between transparent electrodes (not shown), and an electric field is applied between the transparent electrodes to excite the EL luminous body. This is effective for the present embodiment.

[Second Embodiment] FIG. 2 is a conceptual diagram of a film scanner according to a second embodiment of the present invention. In an image reading apparatus that reads an image of a transparent document such as a film scanner, the illumination light source is located at a position facing the imaging optical system with the transparent document interposed therebetween, so that the illumination light source does not locally interfere. Therefore, the light source can be brought as close as possible to the read area on the document depending on the device.

In the present embodiment, the linear light source 4 is obtained by joining the EL 6 which is a surface light source and the waveguide plate 7, and is provided on the surface of the waveguide plate 7 made of a transparent material. The light-emitting surface of EL6 is closely attached. The surface of the coupling between the EL 6 and the waveguide plate 7 is processed to have a sawtooth-shaped cross section as shown in the figure, and the light flux exiting the EL 6 is coupled to the inside of the waveguide plate 7. It plays the role of making it easier. A high-reflectance coating 8 (for example, a metal reflective film such as aluminum) is applied on a plane of the waveguide plate 7 opposite to the EL 6 by painting or vapor deposition, and is coupled over the wide area. Of the luminous flux, the component refracted in the form of a sawtooth wave and incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate 7 and reaches the end of the waveguide plate 7. To reach.

A part of the light beam which is going to penetrate through the waveguide plate 7 is reflected on that surface and returned to the EL6 surface, but is diffused again on the EL6 surface to be reflected in the waveguide of the waveguide plate 7. Returned to. Of those light beam components, the light beam incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate and reaches the end of the waveguide plate.

The end of the waveguide plate 7 has a width corresponding to the thickness of the waveguide plate, and becomes a linear light source 4 having a length equal to one side of the waveguide plate 7 as shown in the figure. That is, a light beam that emits light in a wide area, although the light amount is low, is collected by the waveguide plate 7 and emitted as a linear light source 4 from one end face of the waveguide plate 7.

As shown in the figure, the end face of the waveguide plate 7 is arranged near the surface of the reading film 1, and the light beam extracted linearly illuminates the surface of the film 1 linearly. The linearly illuminated area on the film 1 is imaged on the line CCD 2 by the imaging lens 3 as shown in FIG. 1, and is taken out as a one-dimensional image signal. Then, the film 1 is moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main scanning direction).
To sequentially capture the information of the entire two-dimensional screen. E
The light emission of L6 is prescribed to be white, and color reading is possible using an RGB three-line CCD.

[Third Embodiment] FIG. 3 shows a film scanner according to a third embodiment of the present invention.

In an image reading apparatus such as a film scanner for reading an image on a transparent original, the illumination light source is located at a position facing the image forming optical system with the transparent original being interposed therebetween, so that it does not interfere in place. Therefore, the light source can be brought as close as possible to the read area on the document depending on the device. An image can be clearly read even at a low light amount by bringing the light source close to the light source.

In this embodiment, the linear light source 4 is formed by joining an EL6, which is a surface light source, to the waveguide plate 7, and faces the EL6 of the waveguide plate 7 made of a transparent material. The light-emitting surface of EL6 is adhered to the surface to be formed. The surface of the coupling between the EL 6 and the waveguide plate 7 is processed to have a sawtooth waveform cross section as shown in the figure, so that the light flux exiting the EL 6 is easily coupled into the waveguide plate 7. Plays a role.

On the surface of the waveguide plate 7 opposite to the EL6 side, a high-reflectance coating 8 (for example, a metal reflection film of aluminum or the like) is formed, and coupling is performed over the wide area. The component of the light beam that enters at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate 7 and reaches the end of the waveguide plate. Except for one side of the film 1 on which the light beam is extracted and the saw-tooth wave portion facing the EL 6, the other end of the waveguide plate 7 is also provided with a high-reflectance coating 8 (for example, a metal such as aluminum). A light beam that has propagated through the waveguide and has reached the other end of the side other than the light beam extraction port is reflected there, and reaches the light beam extraction end inside the waveguide plate 7 again. Propagate until you do.

The luminous flux component of the luminous flux that is going to penetrate through the waveguide plate 7 is reflected on that surface and returned to the EL surface, but is diffused again on the EL surface and returned into the waveguide. Of those light beam components, the light beam incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate and reaches the end of the waveguide plate.

The end of the waveguide plate 7 has a width corresponding to the thickness of the waveguide plate, and becomes a linear light source 4 having a length equal to one side of the waveguide plate 7 as shown in the figure. That is, although the light amount is low, a light beam emitted in a linear wide area is gathered by the waveguide plate 7 and emitted from one end face of the waveguide plate 7 as the linear light source 4.

As shown in FIG. 3, the end face of the waveguide plate 7 is arranged near the surface of the reading film 1, and the light beam extracted linearly illuminates the surface of the film 1 linearly. The linearly illuminated area on the film 1 is formed on the line CCD 2 by the imaging lens 3 as shown in FIG. 1, and is taken out as a one-dimensional image signal. Then, the film is sequentially moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main-scanning direction) to take in information of the entire two-dimensional screen. EL6
The light emission is white, and color reading is possible using a three-line CCD.

[Fourth Embodiment] FIG. 4 is a schematic view of a film scanner according to a fourth embodiment of the present invention. In an image reading apparatus that reads an image of a transparent document such as a film scanner, the illumination light source is located at a position facing the imaging optical system with the transparent document interposed therebetween, so that the illumination light source does not locally interfere. Therefore, the light amount can be used more effectively when the light source is closer to the read area on the document.

In this embodiment, the linear light source 4 is formed by joining an EL6, which is a surface light source, to the waveguide plate 7 and faces the EL6 of the waveguide plate 7 made of a transparent material. The light-emitting surfaces of the EL6 are brought into close contact with both surfaces. The surface of the coupling between the EL 6 and the waveguide plate 7 is processed to have a sawtooth-shaped cross section as shown in the figure, so that the light flux exiting the EL 6 can be easily coupled into the waveguide plate 7. Plays. As shown in the lower part of FIG. 4, of the light fluxes coupled from the EL 6 over a large area, the components incident at an angle close to parallel to the waveguide surface propagate while totally reflecting inside the waveguide plate 7. Then, it reaches the end of the waveguide plate 7.

A part of the light beam that has penetrated the waveguide plate 7 is reflected by the above-mentioned diffusion surface on the diffusion reflection surface and returned into the waveguide. Of those light beam components, the light beam incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate 7 and reaches the end of the waveguide plate 7.

The end of the waveguide plate 7 has a width corresponding to the thickness of the waveguide plate, and becomes a linear light source 4 having a length equal to one side of the waveguide plate 7 as shown in the figure. That is, a light beam, which has a low light amount but emits light over a wide area due to the EL 6, is collected by the waveguide plate 7 and emitted from one end face of the waveguide plate 7 as the linear light source 4.

As shown in FIGS. 4 and 1, the end face of the waveguide plate 7 is arranged near the surface of the reading film 1, and the light beam extracted linearly illuminates the surface of the film 1 linearly. The linearly illuminated area on the film 1 is imaged on the line CCD 2 by the imaging lens 3 and is taken out as a one-dimensional image signal. Then, the film 1 is sequentially moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main-scanning direction) to take in information of the entire two-dimensional screen. EL
The light emission of No. 6 is prescribed to be white, and color reading is possible using a three-line CCD.

[Fifth Embodiment] FIG. 5 is a conceptual view of a part of a film scanner according to a fifth embodiment of the present invention. In an image reading apparatus that reads an image of a transparent original such as a film scanner, the illumination light source is located at a position facing the image forming optical system with the transparent original being interposed therebetween and does not locally interfere therewith. Therefore, the illumination light source can be disposed close to the read area on the document, and the light amount can be used effectively.

In this embodiment, the linear light source 4 is obtained by bonding the EL 6 which is a surface light source and the waveguide plate 7, and both surfaces of the waveguide plate 7 made of a transparent material are used. The light emitting surface of the EL is brought into close contact. The surface of the coupling between the EL 6 and the waveguide plate 7 is processed to have a sawtooth-shaped cross section as shown in the figure, so that the light flux exiting the EL 6 can be easily coupled into the waveguide plate 7. Plays a role. EL6
From the light flux coupled in the wide area, the component incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate 7, Reach the end.

Except for the end of one side from which the light beam is taken out, the end of the waveguide plate 7 is also provided with a coating 8 having a high reflectivity (for example, a metal reflective film such as an aluminum AL coat). The light beam that has propagated through the waveguide and arrives at the end of the side other than the light beam extraction port is reflected there, and propagates through the waveguide plate 7 again until it reaches the light beam extraction end.

A part of the light beam that has penetrated the waveguide plate 7 is reflected by the above-mentioned diffusion surface on the opposite side to the diffuse reflection surface, and is returned into the waveguide. Of those light beam components, the light beam incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate 7 and reaches the end of the waveguide plate 7 on the film side. .

The end of the waveguide plate 7 has a width corresponding to the thickness of the waveguide plate, and becomes a linear light source 4 having a length equal to one side of the waveguide plate as shown in the figure. That is, a light beam that emits light in a wide area, although the light amount is low, is collected by the waveguide plate 7 and emitted as a linear light source 4 from one end face of the waveguide plate 7.

As shown in FIGS. 5 and 1, the end face of the waveguide plate 7 is arranged near the surface of the reading film, and the light beam extracted linearly illuminates the surface of the film 1 linearly. The linearly illuminated area on the film 1 is imaged on the line CCD 2 by the imaging lens 3 and is extracted as a one-dimensional image signal. Then, the film 1 is sequentially moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main scanning direction), and the information of the entire two-dimensional screen of the transmitted light of the film 1 is captured. The light emission of EL6 is prescribed to be white, and color reading is possible using a three-line CCD.

[Sixth Embodiment] FIG. 6 is a schematic view of a linear light source of a part of a film scanner according to a sixth embodiment of the present invention. In an image reading apparatus that reads an image of a transparent original such as a film scanner, the illumination light source is located at a position facing the image forming optical system with the transparent original being interposed therebetween, so that it does not interfere with the location. Therefore, the light source can be arranged very close to the read area on the document.

In this embodiment, the linear light source 4 is formed by joining the EL 6 which is a surface light source and the waveguide plate 7, and the linear light source 4 is provided on the surface of the waveguide plate 7 made of a transparent material. The light-emitting surface of EL6 is closely attached. The surface of the coupling between the EL 6 and the waveguide plate 7 is processed to have a sawtooth wave cross section, and has a function of facilitating the coupling of the light flux exiting the EL 6 into the waveguide plate 7.

The surface of the waveguide plate 7 opposite to the EL 6 is coated with a high-reflectance coating (for example, a metal reflection film of aluminum or the like) so that the light flux coupled over the wide area can be used. The component incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate 7, and reaches the end of the waveguide plate 7 on the film side.

Except for the end of one side from which the light beam is extracted, the end of the waveguide plate 7 opposite to the film side is also coated with a high-reflectance coating (for example, a metal reflection film such as aluminum). The light that propagates through the waveguide and reaches the end of the side that is not the light output port is AL
The light is reflected by the coating and propagates again through the waveguide plate 7 until it reaches the end on the film side for extracting the light flux.

Further, the end portion of the waveguide plate 7 from which the light beam is taken out is provided with a predetermined shape so that the reflected light beam having a convex shape is converged at the center portion, and the light beam to be taken out is formed by the linear light source 4. The uniform distribution is maintained in the main scanning direction, which is the line direction of.

A part of the light beam which is going to penetrate through the waveguide plate 7 is reflected on that surface and returned to the EL surface, but is diffused again on the EL surface and returned into the waveguide. Of those light beam components, the light beam incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate 7 and reaches the end of the waveguide plate 7.

The end of the waveguide plate 7 on the film side is the waveguide plate 7
And a linear light source 4 having a length equal to one side of the waveguide plate as shown in the figure. That is, a light beam which emits light in a wide area, although the light amount is low, is collected by the waveguide plate, and emitted from one end face of the waveguide plate 7 as the linear light source 4.

As shown in FIGS. 6 and 1, the end face of the waveguide plate 7 is arranged near the surface of the reading film 1, and the linearly extracted light flux illuminates the surface of the film 1 linearly. The linearly illuminated area on the film 1 is imaged on the line CCD 2 by the imaging lens 3 and the transmitted light is
It is extracted as a two-dimensional image signal. Then, the film 1 is sequentially moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main scanning direction), and information of the entire screen in the two-dimensional area is captured. The emission of EL6 is prescribed to be white, and color reading is possible using a 3-line CCD.

[Seventh Embodiment] FIG. 7 is a schematic view of a part of a linear light source of a film scanner according to a seventh embodiment of the present invention. In an image reading apparatus that reads an image of a transparent original such as a film scanner, the illumination light source is located at a position facing the image forming optical system with the transparent original being interposed therebetween, so that it does not interfere with the location. Therefore, the light source can be arranged close to the read area on the document.

In this embodiment, the linear light source 4 is obtained by bonding the EL 6 which is a surface light source and the waveguide plate 7, and both surfaces of the waveguide plate 7 made of a transparent material are used. EL6
The light-emitting surfaces are closely attached. The surface of the coupling between the EL 6 and the waveguide plate 7 is processed to have a sawtooth wave cross section, and has a function of facilitating the coupling of the light flux exiting the EL 6 into the waveguide plate 7. Of the light fluxes coupled over the wide area from EL 6, the components incident at an angle close to parallel to the waveguide surface propagate while totally reflecting inside waveguide plate 7, and the film side of waveguide plate 7 To the end of the.

Except for one end on the film side from which a light beam is extracted, the other end of the waveguide plate 7 is also provided with a coating 8 having a high reflectivity (for example, a metal reflective film such as aluminum). The light beam that has propagated through the waveguide and has reached the end of the side other than the light beam extraction port is reflected there, and propagates through the waveguide plate 7 until it reaches the light beam extraction end.

Further, a predetermined shape is formed on an end portion of the waveguide plate 7 on the side opposite to the film side end for extracting the light beam so that the extracted light beam maintains a uniform distribution in the main scanning direction. I do.

A part of the light beam that has penetrated the waveguide plate 7 is reflected by the diffusion surface at the above-mentioned diffusion surface, and is returned into the waveguide. Of those light beam components, the light beam incident at an angle close to parallel to the waveguide surface is the waveguide plate 7.
The light propagates while being totally reflected inside, and reaches the end of the waveguide plate 7 on the film side.

The end of the waveguide plate 7 has a width corresponding to the thickness of the waveguide plate 7 and becomes a linear light source having a length equal to one side of the waveguide plate as shown in the figure. That is, a light beam which emits light in a wide area, although the light amount is low, is gathered by the waveguide plate and emitted from one end face of the waveguide plate 7 as a linear light source.

As shown in FIGS. 7 and 1, the end face of the waveguide plate 7 is arranged near the surface of the reading film 1, and the light beam extracted linearly illuminates the surface of the film 1 linearly. The linearly illuminated area on the film 1 is imaged on the line CCD 2 by the imaging lens 3 and is extracted as a one-dimensional image signal. Then, the film is sequentially moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main-scanning direction) to take in information of the entire two-dimensional screen. EL
The light emission of No. 6 is prescribed to be white including RGB light, and color reading is possible using an RGB three-line CCD.

[Eighth Embodiment] FIG. 8 is a schematic diagram showing a linear light source of a part of a film scanner according to an eighth embodiment of the present invention. In an image reading apparatus that reads an image of a transparent original such as a film scanner, the illumination light source is located at a position facing the image forming optical system with the transparent original being interposed therebetween, so that it does not interfere with the location. Therefore, the light source can be arranged close to the read area on the document.

In this embodiment, the linear light source 4 is obtained by joining the EL 6 which is a surface light source and the waveguide plate 7, and is provided on the surface of the waveguide plate 7 made of a transparent material. The light-emitting surface of EL6 is closely attached. The surface of the coupling between the EL 6 and the waveguide plate 7 is processed to have a sawtooth wave cross section, and has a function of facilitating the coupling of the light flux exiting the EL 6 into the waveguide plate 7. E in the waveguide plate 7
On the surface opposite to L6, a coating (not shown) having a high reflectance (for example, a metal reflection film such as aluminum) is provided.
The component of the light beam coupled in the wide area that enters at an angle close to parallel to the waveguide surface is a component of the waveguide plate 7.
The light propagates while being totally reflected inside, and reaches the end of the waveguide plate 7 on the film side. Except for the end of one side from which the light beam is taken out, the end of the waveguide plate 7 is also coated with a high-reflectance coating (for example, a metal reflective film such as aluminum).
The light beam that has propagated through the waveguide and has reached the end of the side other than the light beam extraction port is reflected there, and propagates again in the waveguide until it reaches the light beam extraction end.

A part of the light beam emitted from the EL 6 which is going to penetrate through the waveguide plate 7 is reflected on that surface and returned to the EL surface, but is diffused again on the EL surface to enter the waveguide. Will be returned. Of those light beam components, the light beam incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate and reaches the end of the waveguide plate.

In the present embodiment, the surface where the EL 6 and the waveguide plate 7 are coupled has a predetermined shape that is convex from the film side, so that the light beam extracted from the end surface can be seen from the main scanning direction in the linear direction. The emitted light quantity is kept uniform.

The end on the film side of the waveguide plate 7 is
And a linear light source having a length equal to one side of the waveguide plate as shown in the figure. That is, a light beam that emits light over a wide area, although the light amount is low, is collected by the waveguide plate 7 and emitted from one end face of the waveguide plate 7 as a linear light source.

As shown in FIGS. 8 and 1, the end face of the waveguide plate is arranged near the surface of the reading film 1 and the light beam extracted linearly illuminates the surface of the film 1 linearly. The area on the film 1 illuminated linearly is the imaging lens 3
The image is formed on the line CCD 2 and is extracted as a one-dimensional image signal. Then, the film is sequentially moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main scanning direction), and information of the entire two-dimensional screen is captured. Also, E
The light emission of L is prescribed to be white, and color reading is possible using a 3-line CCD.

[Ninth Embodiment] FIG. 9 is a schematic view of a linear light source of a film scanner according to a ninth embodiment of the present invention. In an image reading apparatus that reads an image of a transparent original such as a film scanner, the illumination light source is located at a position facing the image forming optical system with the transparent original being interposed therebetween, so that it does not interfere with the location. Therefore, the illumination light source can be arranged close to the read area on the document.

In this embodiment, the linear light source 4 is formed by bonding an EL 6 which is a surface light source and a waveguide plate 7. Both surfaces of the waveguide plate 7 made of a transparent material are shown. And EL
6, 9 light-emitting surfaces are adhered.

The surface of the coupling between the EL 6 and the waveguide plate 7 is processed to have a sawtooth wave cross section.
The light flux exiting from 6 is easily coupled into the waveguide plate. Of the light fluxes coupled in the wide area from EL6, the component incident at an angle close to parallel to the waveguide surface propagates while being totally reflected in the waveguide plate and reaches the end of the waveguide plate. I do.

Except for the end of one side from which the light beam is taken out, the other end of the waveguide plate is also coated with a coating having a high reflectivity (for example, a metal reflection film such as aluminum). The luminous flux that has propagated and reaches the end of the side other than the luminous flux exit port is reflected there, and propagates again in the waveguide until it reaches the luminous flux exit end.

Further, a predetermined shape is formed on the surface where the ELs 6, 9 and the waveguide plate 7 are coupled so that the light flux extracted from the end face maintains a uniform distribution in the main scanning direction.

A part of the light beam that has penetrated the waveguide plate 7 is diffusely reflected by the diffusion surface, which is the light emitting surface of the opposing EL 6, 9, and is returned into the waveguide. Of these light beam components, the light beam incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate, and reaches the end of the waveguide plate.

The end of the waveguide has a width corresponding to the thickness of the waveguide, and becomes a linear light source having a length equal to one side of the waveguide as shown in the figure. That is, a light beam that emits light over a large area, although the light amount is low, is collected by the waveguide plate and emitted from one end face of the waveguide plate as a linear light source.

As shown in FIG. 9 and FIG. 1, the end face of the waveguide plate is arranged near the surface of the reading film 1, and the light beam extracted linearly illuminates the surface of the film 1 linearly. The linearly illuminated area on the film 1 is imaged on the line CCD 2 by the imaging lens 3 and is extracted as a one-dimensional image signal. Then, the film is sequentially moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main scanning direction), and information of the entire two-dimensional screen is captured. The EL emission is prescribed to be white, and color reading is possible using a three-line CCD.

[Tenth Embodiment] FIG. 10 is a schematic diagram showing a linear light source of a part of a film scanner according to a tenth embodiment of the present invention. In an image reading apparatus that reads an image of a transparent original such as a film scanner, the illumination light source is located at a position facing the image forming optical system with the transparent original being interposed therebetween, so that it does not interfere with the location. Therefore, the illumination light source can be arranged close to the read area on the document.

In the present embodiment, the linear light source 4 is formed by joining the EL6, which is a surface light source, to the waveguide plate 7, and is applied to both surfaces of the waveguide plate made of a transparent material. The light-emitting surface of EL6 is closely attached. One EL is adhered to one side, and two ELs are adhered to opposing surfaces. Each of the ELs is configured to emit light of each color of R, G, and B, and EL light emitters of each color are formed between the transparent electrodes, respectively, and an electric field is applied for each color to emit EL light. Further, the arrangement of RGB is not limited to the arrangement shown in FIG. 10, but is arranged in consideration of the photoelectric conversion sensitivity of the CCD of the line sensor of each color through the film surface.

The surface of the coupling between the EL 6 and the waveguide plate 7 is processed to have a sawtooth-shaped cross section, so that the light flux exiting the EL 6 is easily coupled into the waveguide plate 7. I have. Of the light fluxes coupled in the wide area from EL6, the component incident at an angle close to parallel to the waveguide surface propagates while being totally reflected in the waveguide plate and reaches the end of the waveguide plate. I do.

A part of the light beam that has penetrated through the waveguide plate is reflected by the above-mentioned diffusion surface at the diffusion reflection surface, and is returned into the waveguide. Of those light beam components, the light beam incident at an angle close to parallel to the waveguide surface propagates while totally reflecting inside the waveguide plate and reaches the end of the waveguide plate.

The end of the waveguide plate on the film side has a width corresponding to the thickness of the waveguide plate, and becomes a linear light source having a length equal to one side of the waveguide plate as shown in the figure. That is, a light beam that emits light over a large area, although the light amount is low, is collected by the waveguide plate and emitted from one end face of the waveguide plate as a linear light source.

As shown in FIG. 10 and FIG. 1, the end face of the waveguide plate is arranged near the surface of the reading film 1, and the light beam extracted linearly illuminates the surface of the film 1 linearly. The linearly illuminated area on the film 1 is imaged on the line CCD 2 by the imaging lens 3 and is extracted as a one-dimensional image signal. Then, the film 1 is moved in a direction (sub-scanning direction) perpendicular to the linear illuminated area (main scanning direction).
To capture the information of the entire two-dimensional screen.
The EL6 can emit light of three colors independently, and a color image of a transparent original can be read by using a one-line CCD by switching light sources.

In the above-described embodiment, the coupling between the waveguide plate 7 and the EL has been described, but the present invention is not limited to these embodiments. For example, the shape of the waveguide plate 7 may be a linear light source. The width of the other end face may be made narrower by increasing the width of the emission end face, or may be made a triangular shape by making the width of the other end face substantially zero. Also, while the description has been given of the case where the light quantity at the emission end face of the waveguide plate is made uniform, it is possible to emit light with the light quantity of the EL itself being inclined in the vertical direction of the emission end face in FIG. In addition, the shape of the coupling lens shown in FIG. 1 may be a cylindrical lens of a Kamaboko type corresponding to a linear light source.

[0080]

By adopting the structure of the light source according to the present invention, the EL, which is a low-cost and stable surface light source with a small amount of light.
As a light source, it is possible to obtain a linear light source having a sufficient luminance by the light condensing effect of the waveguide plate.

The light emission distribution of the linear light source can be controlled by the shape of the end face of the waveguide plate and the light emitting surface of the EL. A white light source is obtained by EL prescribed for white light emission, and three-line color C
Image reading by CD is possible. In addition, EL of different colors can be used in combination, and a color image can be read by a one-line CCD by switching light sources.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a film scanner according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a film scanner according to a second embodiment of the present invention.

FIG. 3 is a schematic view of a film scanner according to a third embodiment of the present invention.

FIG. 4 is a schematic view of a film scanner according to a fourth embodiment of the present invention.

FIG. 5 is a schematic view of a film scanner according to a fifth embodiment of the present invention.

FIG. 6 is a schematic view of a film scanner according to a sixth embodiment of the present invention.

FIG. 7 is a schematic view of a film scanner according to a seventh embodiment of the present invention.

FIG. 8 is a schematic view of a film scanner according to an eighth embodiment of the present invention.

FIG. 9 is a schematic view of a film scanner according to a ninth embodiment of the present invention.

FIG. 10 is a schematic view of a film scanner according to a tenth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film 2 CCD 3 Lens 4 Waveguide plate 6 EL 7 Waveguide plate

Claims (12)

[Claims] 1. An image reading apparatus comprising a light source for illuminating a part of a transmission type document surface, comprising: a surface-emitting light source; and a light guide for guiding a light beam emitted from the light source. Emit from the end face of the light body, resulting in approximately 1
An image reading device, which illuminates the transparent document surface in a two-dimensional manner. 2. An image reading apparatus comprising: a light source for illuminating a part of a transmissive document surface; and a photoelectric conversion element for receiving light transmitted from the light source, wherein the light source emits surface light and the light source emits light. A light guide for guiding the light flux, the light guide having a high reflection coating on a surface facing the light source for surface light emission, and radiating from an end face of the light guide, and as a result, the light guide becomes substantially one-dimensional. An image reading device, which illuminates the surface of a document. 3. An image reading apparatus comprising: a light source for illuminating a part of a transmission type document surface; and a photoelectric conversion element for receiving a transmitted light from the light source, wherein the light source emits surface light and the light source emits light. A light guide that guides the light flux, the light guide having a high reflection coating on all the end faces other than the face facing the surface light source and the end face from which the light flux is taken out, and from the end face of the light guide. An image reading apparatus which emits light and illuminates the surface of a document in a substantially one-dimensional manner as a result. 4. An image reading apparatus comprising: a light source for illuminating a part on a transmission type document surface; and a photoelectric conversion element for receiving transmitted light from the light source. A light guide that is disposed between the surface light sources and guides light emitted from the two surface light sources from both sides, and radiates the light from the end face of the light guide toward the transmissive original. An image reading apparatus for illuminating a document surface in a two-dimensional manner. 5. An image reading apparatus comprising: a light source for illuminating a part of a transmission-type document surface; and a photoelectric conversion element for receiving transmitted light from the light source, wherein the light source emits two surfaces and the light source. A light guide that guides the light flux emitted from both sides from both sides, and the light guide has a high reflection coating on all end faces other than the face on which the light flux is taken out and the end face on the transmission type original side, An image reading device, wherein light is emitted from an end surface of the light source on the side of the transmission type document, and as a result, the surface of the document is illuminated substantially one-dimensionally. 6. An image reading apparatus comprising: a light source for illuminating a part of a transmission type document surface; and a photoelectric conversion element for receiving a transmitted light from the light source, wherein the light source emits a surface light; A light guide for guiding the light beam; and a high-reflection coat provided on the surface of the light guide facing the surface light source. The light guide emits light from an end surface of the transmission-type original surface side of the light guide and emits the light. A predetermined shape is applied to the opposite end faces of the end faces, and as a result, the emitted light flux has a uniform distribution in the linear direction of the emitting end faces, and illuminates the document surface in a substantially one-dimensional shape. Image reading device. 7. An image reading apparatus comprising: a light source for illuminating a part of a transmission type document surface; and a photoelectric conversion element for receiving transmitted light from the light source, comprising: two surface-emitting light sources; A light guide that guides a light beam emitted from the surface emitting light source from both sides, radiates from the end surface of the light guide, gives a predetermined shape to an end surface opposite to the radiating end surface, and emits a light beam as a result. Has a uniform distribution, and illuminates the document surface in a substantially one-dimensional shape. 8. An image reading apparatus comprising: a light source for illuminating a part on a transmission type document surface; and a photoelectric conversion element for receiving transmitted light from the light source, wherein: a surface-emitting light source for surface-emitting light; A light guide for guiding a light beam emitted from the light emitting light source; and a high-reflection coating on a surface of the light guide facing the surface light source. The light guide emits light from an end face of the light guide, and a predetermined light is emitted to the surface light source. An image reading device having a uniform distribution of light beams emitted as a result, and illuminating the document surface in a substantially one-dimensional shape. 9. A light source device for illuminating a part of a document surface, comprising: a linear light source that guides light emitted from two surface light sources from both sides of the light guide. A light source that emits light from an end face of the light source and forms the two surface-emitting light sources into a predetermined shape, so that the emitted light flux has a uniform distribution and illuminates the surface of the document substantially one-dimensionally. apparatus. 10. A light source device for illuminating a part of a document surface, comprising: a linear light source for guiding light beams emitted from three surface light sources from both sides of a light guide; One surface emitting light source is arranged on one side and two surface emitting light sources on the other side, and the three types of surface emitting light sources have different colors, respectively, and the three types of surface emitting light sources can be turned on independently of each other. A light source device, wherein a light beam radiated from an end surface and radiated as a result illuminates the surface of a document substantially one-dimensionally. 11. A light source device for illuminating a part of a document surface, comprising a linear light source for guiding a light beam emitted from a surface emitting light source by a light guide, and radiating the light from an end face of the light guide. , Resulting in approximately 1
A light source device for illuminating the surface of the transparent document in a two-dimensional manner. 12. A light source device for illuminating a part on a document surface, comprising a linear light source for guiding a light beam emitted from a surface-emitting light source by a light guide, wherein the light guide is configured to emit the surface light. A light source device having a high-reflection coating on a surface facing a light source, radiating light from an end surface of the light guide, and thereby illuminating the document surface in a substantially one-dimensional shape.