JPH08211511A - Original image pickup device for copying machine or the like - Google Patents

Abstract

PURPOSE: To surely prevent the imprinting of light emitted from a light source and to uniformly illuminate an object surface. CONSTITUTION: Cases 21 are symmetrically arranged in the vicinity of both sides of a transparent glass plate 3, fluorescent lamps 6a and 6b are separately stored and arranged in the cases 21. And the opening part of the case 21 is covered with a cylindrical lens 23 so as to constitute an illuminator 20. An original 5 is irradiated with the light from the illuminator 20, and the video is photographed by a television camera 7. The imprinting of the light emitted from the fluorescent lamps 6a and 6b to the camera is reduced by adjusting the inclined angle α of a reflection mirror 4 and the inclined angle β of the camera 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manuscript image pickup device such as a copying machine for covering a manuscript placed on a transparent glass plate with a lid and irradiating light through the transparent glass plate to pick up the manuscript.

[0002]

2. Description of the Related Art Generally, in a copying machine, a plain paper OHP (overhead projector) or the like, an original is placed on a transparent glass plate with the surface of the original facing down, and light is emitted from below the transparent glass plate. It is configured to irradiate and image using a camera or the like. Figure 3 shows such plain paper OHP
FIG. 1 is a schematic configuration diagram showing a conventional example of FIG. 1, 1 is an apparatus housing, and 2 is a document imaging apparatus arranged in the apparatus housing 1. The original image pickup device 2 has a horizontal transparent glass plate 3 provided on the upper surface of the device casing 1 and a predetermined angle θ (θ) with respect to the transparent glass plate 3.
= 45 °) and a pair of left and right light sources (fluorescent lamps) for irradiating the reflection mirror 4 arranged in the apparatus housing 1 with inclination and the original 5 placed on the transparent glass plate 3 through the transparent glass plate 3. 6
a and 6b, and a TV camera 7 for picking up an image of the document 5 and the like. The distance between the camera 7 and the original 5 is preferably as short as possible, but considering the use of a zoom lens, it is necessary to be 300 mm or more for design reasons. Further, the illuminance becomes more uniform when the light sources 6a and 6b are also arranged closer to the center of the original 5 to the extent that they do not fall within the view reflection angle of the camera 7. Note that the uniform illuminance means that the illuminance ratio (the ratio of the illuminance to the brightest place in the darkest place) is 50% or more. It is necessary to secure this shooting condition in order to obtain a more beautiful image. is there. 13 is the original 5
It is a lid that covers.

In such a structure, at the time of image pickup, the original 5 is placed on the transparent glass plate 3 with its surface to be picked up facing down, and the lid 13 covers the upper surface of the original 5. And 2
The two light sources 6a and 6b are turned on to illuminate the original surface of the original under the original 5 to be imaged through the transparent glass plate 3. At this time, most of the irradiation light strikes the document surface of the document 5 and is reflected. Then, this reflected light is guided to the camera 7 by the reflection mirror 4. In this case, the light reflectance of characters and the like on the original 5 is lower than the reflectance of the original 5 itself (10 to 30%).
Therefore, characters and the like on the document surface are imaged by the camera 7 due to the difference in reflectance. The reflection mirror 4 is usually inclined 45 ° with respect to the transparent glass plate 3, in other words, with respect to the horizontal plane, and the camera 7 is installed horizontally.

[0004]

However, in the above-mentioned conventional plain paper OHP, since the fluorescent lamps 6a and 6b, which are the light sources, are located inside the camera visual field reflection angle, these fluorescent lamps 6a and 6b are located. Part of the light A1 and B1 radiated upward from is reflected by the document 5 and is further reflected by the reflection mirror 4 and reflected on the camera 7, and the light source light is recognized as an image. There was a problem. In order to prevent such a reflection on the camera 7, the lights A1 and B1 from the respective fluorescent lamps 6a and 6b are fluorescent to the outside thereof in consideration of the amount of the camera viewing angle reflected on the transparent glass plate 3. The lights 6a and 6b may be moved. However, in that case, the amount of light in the central portion of the document is reduced due to the light attenuation, and the uniformity of illumination is lost. Further, a part of the light from the fluorescent lamp 6b, that is, the light emitted obliquely downward from the fluorescent lamp 6b, hits the reflecting mirror 4 and is reflected upward, is transmitted through the transparent glass plate 3 and is reflected downward by the original 5 and is reflected again by the reflecting mirror 4. As for the reflected light B2 which is reflected on the camera 7 and enters the camera 7, a shutter 12 is provided in front of the fluorescent lamp 6b to block the reflected light B2. In this case, the reflected light B2 itself irradiates the document 5 and is necessary for photographing. As with the case described above, there is a problem that the uniformity of illumination is lost.

Therefore, the present invention has been made in view of the above conventional problems, and an object thereof is to construct an illuminating device with a fluorescent lamp and a cylindrical lens, and to reflect the transparent glass. An object of the present invention is to provide an original image pickup device such as a copying machine in which the light source light is reliably prevented from being projected and the object surface can be uniformly illuminated by changing the installation angles of the mirror and the camera.

[0006]

In order to achieve the above-mentioned object, the present invention provides an illuminating device arranged on both lower sides of a transparent glass plate on which an original is placed, and irradiates the original with the illuminating device. In a document image pickup device such as a copying machine provided with a reflection mirror for reflecting the reflected light and a camera for picking up the reflected light, the transparent glass plate is provided so that the illuminating device is located outside the camera viewing angle. A pair of cases respectively disposed on both sides of each of the cases, a fluorescent lamp housed in each of the cases, and a cylindrical member that covers the opening of each case and collects the light from the fluorescent lamp to guide it to the document. It is characterized by being configured with a lens.
Further, the present invention is characterized in that the reflection mirror is inclined at an angle of 30 ° to 40 ° with respect to the surface of the transparent glass plate. Further, the present invention is characterized in that the camera is inclined at an angle of 30 ° to 10 ° with respect to the surface of the transparent glass plate. Furthermore, the present invention arranges the fluorescent lamp and the cylindrical lens in parallel with their longitudinal directions aligned with each other, and offsets the fluorescent lamp from the optical axis center of the cylindrical lens, and the optical axis of the cylindrical lens is It is characterized in that it is inclined so as to intersect with the surface of the transparent glass plate.

[0007]

In the present invention, the cylindrical lens makes it possible to dispose the illuminating device outside the reflection angle of the visual field of the camera, and there is little projection on the camera. Further, the cylindrical lens collects the light from the fluorescent lamp and guides it to the document surface, and illuminates a portion far from the fluorescent lamp brightly. When the fluorescent lamp is arranged on the center line of the optical axis of the cylindrical lens, the light around the center of the optical axis becomes a pseudo-parallel light beam and becomes larger than the peripheral light amount. Therefore, if the fluorescent lamp is offset from the optical axis center of the cylindrical lens, the amount of light around the center of the optical axis decreases and the amount of light in the peripheral portion increases.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 1 is a schematic configuration diagram showing an embodiment in which the present invention is applied to plain paper OHP. The plain paper OHP optically captures characters and the like written on a document 5 made of plain paper by the document imaging device 2, visualizes them using a liquid crystal panel, and projects them on a screen (not shown) in an enlarged manner. This type of device is described in detail in, for example, Japanese Patent Application No. 5-198849, so that the detailed description thereof will be omitted here. Further, the same components as those described in the section of the prior art in the figure are denoted by the same reference numerals, and detailed description thereof will be omitted.

Referring to FIG. 1, according to the present invention, an illuminating device 20 for illuminating a document 5 through a transparent glass plate 3 is provided.
A pair of left and right cases 21 arranged close to each other on both lower sides of the
And fluorescent lamps 6a and 6b provided in each case 21,
It is configured by a cylindrical lens 23 provided in the case 21 so as to cover the front opening of each case 21, and the reflection mirror 4 and the camera 7 do not enter the camera 7 as light reflected by the illumination device 20. Angle α to the horizontal,
Each is set with β.

The case 21 is formed in a slender shape in the front-back direction of the apparatus housing 1, and a black paint is applied to the entire inner surface to form a dark box. This is a fluorescent lamp 6a, 6b
This is to prevent the light emitted from the device from hitting the inner surface and being reflected. Each case 21 is symmetrical to the outside,
In other words, the cylindrical lens 23 is directed at the transparent glass plate 3 so that the angle δ with respect to the surface of the transparent glass plate 3.
Only tilted and fixed. The inclination angle δ is 4
It is about 2 °. The fluorescent lamps 6a and 6b have an axis line in the case 2
1 is accommodated in the case 21 such that the axis line is parallel to the surface of the transparent glass plate 3 so as to coincide with the longitudinal direction of 1, and outside the positions of the conventional fluorescent lamps 6a and 6b shown in FIG. That is, it is positioned outside the camera viewing angle. The left and right fluorescent lamps 6a and 6b are parallel to each other and housed in the upper inside of each case 21 to be offset from the optical axis center 24 of the cylindrical lens 23 by a distance D. The reason why the fluorescent lamps 6a and 6b are offset by D from the optical axis center 24 of the cylindrical lens 23 is to obtain uniform illumination. That is,
If the fluorescent lamps 6a and 6b are arranged on the optical axis center line 24 of the cylindrical lens 23, the amount of light around the optical axis center is larger than the amount of light in the peripheral portion and uneven illumination occurs. Therefore, if the fluorescent lamps 6a and 6b are offset from the optical axis center 24 of the cylindrical lens 23 by a distance D above the optical axis center, the amount of light around the optical axis center 24 decreases and the amount of light in the peripheral portion decreases. This is because the overall brightness can be averaged due to the increase. The offset value D is about 15 mm. The cylindrical lens 23 is formed of synthetic resin or glass into a rod-shaped body having a D-shaped cross section. The focal length of the cylindrical lens 23 is 26 m.
m, the distance between the cylindrical lens 23 and the fluorescent lamp 21 is about 5 mm.

The inclination angles α and β of the reflection mirror 4 and the camera 7 with respect to the transparent glass 3 are 35 in this embodiment, respectively.
And 20 °. The camera 7 is arranged above the conventional installation position shown in FIG. 3 because of the inclination angle α of the reflection mirror 4 and the inclination angle β of the camera itself. Other configurations are the same as those of the conventional device shown in FIG.

In the plain paper OHP having such a structure, the left and right fluorescent lamps 6a, 6 are used for photographing the original 5.
When b is turned on and the light is condensed by the cylindrical lens 23 and guided to the original document 5, the entire surface of the original document 5 can be illuminated with substantially uniform brightness, and uniform illumination with an illuminance ratio of 50% or more is possible. To do. Then, in this state, the image of the document 5 is taken by the camera 7.

FIG. 2 is a diagram for explaining the difference between the present invention and the conventional device. As is clear from this figure, in the case of the conventional device in which the reflection mirror 4 is inclined at 45 ° with respect to the horizontal plane, the light C1 emitted from the fluorescent lamp 6b hits the reflection surface of the subject surface after being reflected on the subject surface. It is incident on 7. On the other hand, in the present invention, the light C1 does not enter the camera 7, and another light C2 having a different emission angle illuminates the object surface, and then strikes the reflection mirror 4 and is reflected to enter the camera 7. The irradiation area H1 of the object surface by the light C2 is narrower than the irradiation area H by the light C1. For this reason, the range in which light does not reach the subject surface due to the shutter 12 is narrower for the light C2. In other words, since the shutter 12 cuts unnecessary light C1 that is not the light that illuminates the subject surface, the amount of light that is captured by the camera 7 is equal to the difference between the irradiation regions H and H1 (H-H1). Can be reduced,
Ensure the uniformity of the subject surface.

The irradiation ranges H and H1 from the light source 6b become narrower as the inclination angle α of the reflecting mirror 4 becomes smaller. Also, the narrower the irradiation range, the larger the inclination angle β of the camera 7 with respect to the horizontal plane. The tilt angle α of the reflecting mirror 4 is optimally in the range of 30 ° to 40 °. If the angle is 30 ° or less, the installation position of the camera 7 becomes high, and it becomes difficult to secure the installation space for the illumination device 20, which is not preferable. If the angle is 40 ° or less, imprinting on the camera increases, and there is little difference from the conventional device, which is not preferable. The inclination angle β of the camera 7 is 30 ° as described above.
It is determined by -40 ° and is in the range of 30 ° -10 °.

Further, in FIG. 1, among the lights emitted from the fluorescent lamps 6a and 6b, A1 'and B1' which are directly reflected by the transparent glass plate 3 are arranged with the illuminating device 20 outside the camera viewing angle. Therefore, the light A1 and B shown in FIG.
It is reflected outside the effective reflection area W of the reflection mirror 4 rather than 1. Therefore, the lights A1 ′ and B1 ′ are also not captured by the camera 7.

Further, in the conventional apparatus shown in FIG. 3 which does not use a cylindrical lens, since the fluorescent lamps 6a and 6b are arranged inside the viewing angle of the camera, there is a problem that the uniformity is remarkably impaired as described above. . However, in the present invention, since the lights from the fluorescent lamps 6a and 6b are condensed by using the cylindrical lens 23, even if the fluorescent lamps 6a and 6b are arranged outside the camera viewing angle, the cylindrical lens can be used. It is possible to illuminate far away brightly as in the case of not using the camera and arranging within the camera viewing angle, and to obtain uniform illumination with an illuminance ratio of 50% or more. The inclination angle δ of the optical axis center 24 of the cylindrical lens 23 is preferably in the range of 40 ° to 55 °.

According to the plain-paper OHP original image pickup device having such a structure, the light emitted from the fluorescent lamps 6a and 6b is not reflected on the camera 7, and the original 5 can be uniformly illuminated. .

Although the above embodiment has been described with respect to the case of being applied to an original image pickup apparatus for plain paper OHP, the present invention is not limited to this and can be directly applied to a copying machine. .

[0019]

As described above, the original image pickup device such as a copying machine according to the present invention is provided with an illumination device provided on both lower sides of a transparent glass plate on which an original document is placed, and an illumination device for illuminating. In a document imaging device such as a copying machine provided with a reflection mirror that reflects light reflected by the document and a camera that captures the reflected light, the illumination device is positioned so as to be located outside a camera viewing angle. A pair of cases respectively arranged on both sides of the transparent glass plate, fluorescent lamps housed in the cases, and the originals by covering the openings of the respective cases and condensing light from the fluorescent lamps. Since it is composed of a cylindrical lens that guides the image to the document, it is possible to illuminate the original evenly, as compared with a conventional device that does not use the cylindrical lens, since the image is less reflected on the camera. As a result, the illuminance ratio can be set to 50% or more, and a more beautiful image can be captured. Further, in the present invention, since the fluorescent lamp is arranged offset from the center of the optical axis of the cylindrical lens, the amount of light around the center of the optical axis decreases, the amount of light in the peripheral portion increases, and the overall brightness is averaged. Can be transformed. As a result, uniform illumination is possible.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment in which the present invention is applied to plain paper OHP.

FIG. 2 is a diagram for explaining a difference between the present invention and a conventional device.

FIG. 3 is a schematic configuration diagram of a conventional plain paper OHP document imaging apparatus.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Device housing, 2 ... Original image pickup device, 3 ... Transparent glass plate,
4 ... Reflective mirror, 5 ... Original, 6a, 6b ... Fluorescent lamp, 7 ...
Camera, 20 ... Illumination device, 21 ... Case, 23 ... Cylindrical lens, 24 ... Optical axis center.

Claims (4)

[Claims] 1. An illuminating device arranged on both lower sides of a transparent glass plate on which an original is placed, a reflecting mirror for reflecting light emitted from the illuminating device and reflected by hitting the original, and an image of the reflected light. In a document imaging device such as a copying machine equipped with a camera, a pair of cases in which the illuminating device is disposed on both sides of the transparent glass plate so as to be located outside a camera viewing angle, and these cases. An original document for a copying machine or the like, which is configured by a fluorescent lamp housed inside each of them and a cylindrical lens that covers the opening of each case and collects the light from the fluorescent lamp and guides the light to the original document. Imaging device. 2. An original image pickup device such as a copying machine according to claim 1, wherein the reflection mirror is 30 ° to 40 ° with respect to the surface of the transparent glass plate.
An original image pickup device such as a copying machine characterized by being inclined at an angle of. 3. An original image pickup device such as a copying machine according to claim 2, wherein the camera is 30 ° to the surface of the transparent glass plate.
An original imaging device such as a copying machine, which is tilted at an angle of 10 °. 4. An original image pickup device such as a copying machine according to claim 1, wherein the fluorescent lamp and the cylindrical lens are arranged in parallel with their longitudinal directions aligned with each other, and the fluorescent lamp is located from the optical axis center of the cylindrical lens. An original image pickup device such as a copying machine, wherein the cylindrical lens is offset and the optical axis of the cylindrical lens is inclined so as to intersect the surface of the transparent glass plate.