JPH08336065A - Original illuminator and image input device - Google Patents

Abstract

PURPOSE: To prevent imprinting of a light emission means and to provide appropriate illumination light corresponding to the size of an original to be read by moving the light emission means to a prescribed position corresponding to the image angle and focus position of an image forming means. CONSTITUTION: An Xe tube 2 is attached to the tip of a rack gear 9 in the direction of irradiating an original surface. By the instruction of a CPU 4, a drive circuit 8 drives a motor 11 to which a gear 10 is attached and moves the rack gear 9 and the Xe tube 2. The position of the Xe tube 2 is set beforehand so as to make an optical path length difference shortest within a range without imprinting corresponding to the image angle and focus position of a projecting lens 6. The CPU 4 obtains the moving amount of the rack gear 9 based on the rotation amount of the motor 11 and output from an origin detection means and recognizes the position of the Xe tube 2. When it is judged that the Xe tube 2 is moved to the set position, the drive of the motor 11 is stopped. In this case, the rack gear 9 is in a circular-arcuate shape whose center is the center 3a of the original 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a document illuminating device capable of irradiating a document with an appropriate incident angle to prevent reflection of a light emitting means, and an image input device equipped with the document illuminating device.

[0002]

2. Description of the Related Art For example, in an image input apparatus, a document placed on a document table is irradiated with light from a light source, which is a light emitting means, and the image of the document is photoelectrically converted by a reflected light from the document through a projection lens. When reading with a CCD as a means, the light source is positioned and fixed according to the angle of view and the focus position of the projection lens so that the image reflected by the document of the light source is not reflected within the angle of view of the CCD.

[0003]

When the illumination light source is fixed, the illumination light source is fixed at a position where the image is not reflected even when the angle of view of the lens is maximized. When the angle of view of the lens is set narrow, the range where the illumination light source is not reflected becomes large. However, since the illumination light source is fixed assuming that the angle of view of the lens is the largest, the illumination position cannot be changed according to the angle of view of the lens. Therefore, there is a problem in that it is not always possible to perform shooting and reading at an appropriate illumination position.

The present invention has been made in view of the above circumstances, and an original illuminating device capable of illuminating an original from an appropriate position while preventing the illumination light source as a light emitting means from being reflected in an image. An object of the present invention is to provide an image input device provided with the document illumination device.

[0005]

In order to achieve the above object, the present invention according to claim 1 provides a light emitting means (for example, the Xe tube 2 in FIG. 1) for illuminating a document (for example, the original 3 in FIG. 1).
And an image forming unit (for example, the projection lens 6 in FIG. 1) that forms an image of the illumination light from the document at a predetermined position, in a position where the light emitting unit does not appear in the image forming unit. A moving means (for example, the rack gear 9 in FIG. 1) for moving the light emitting means is provided.

According to a seventh aspect of the present invention, light emitting means (for example, Xe in FIG. 1) for illuminating a document (for example, the original 3 in FIG. 1) is used.
Tube 2), photoelectric conversion means for entering illumination light from the original document and converting it into an electric signal (for example, CCD 1 in FIG. 1), and imaging for forming illumination light from the original document on the photoelectric conversion means An image input device including means (for example, the projection lens 6 in FIG. 1) is provided with the document illumination device according to any one of claims 1 to 6.

[0007]

In the original illuminating device according to the first aspect of the invention, the light emitting means is moved to a predetermined position in accordance with the angle of view and the focal position of the image forming means. Appropriate illumination light can be obtained according to the size.

In the image input device according to the eighth aspect of the present invention, since the reflection of the light emitting means is prevented and the original illuminating device capable of obtaining the appropriate irradiation light according to the size of the original to be read is provided. Since the light emitting means does not appear in the photoelectric conversion means, the image of the original can be accurately input.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a document illuminating device of the present invention and an image input device equipped with the document illuminating device will be described below with reference to the drawings.

FIG. 1 shows the configuration of the first embodiment of the present invention. In FIG. 1, a CCD 1 is a surface sensor, and a document illumination light source is a Xe tube 2. The light emitted from the Xe tube 2 strikes the original 3 placed on the original table 12 and is reflected. Manuscript 3
The reflected light from the light enters the CCD 1 by the function of the projection lens 6, and the original 3 can be read. The focus unit 5 and the zoom unit 7 are connected to the CPU 4. The zoom unit 7 adjusts the angle of view of the projection lens 6 according to a command from the CPU 4. Further, the focus unit 5 focuses the projection lens 6 according to a command from the CPU 4 so that the reflected light from the original 3 is imaged on the CCD 1. Even when the zoom lens is used, the focal position moves slightly with a change in the angle of view. For this reason,
It is desirable to perform focusing after adjusting the angle of view. When the focusing and the angle-of-view adjustment are completed, the two units 5 and 7 send end signals to the CPU 4, respectively.

After the operations of focusing and adjusting the angle of view are completed, Xe
Position the tube 2. The position of the Xe tube 2 is within a range where there is no reflection in the image. As shown in FIGS. 2 and 3,
The reflection range changes depending on the angle of view and the focus position of the projection lens 6. As shown in FIG. 2, when the angle of view of the projection lens 6 is widened or the focal position is farther away, the reflection range A shown by the diagonal line becomes wider. On the contrary, as shown in FIG. 3, when the angle of view of the projection lens 6 is narrowed or the focus position is close, the reflection range B shown by diagonal lines is narrowed. Therefore, FIG. 2 and FIG.
As shown in, the X-axis corresponds to the angle of view and focus position of the projection lens 6.
The position of the e-tube 2 is set in advance so that the difference in optical path length is the shortest within a range without reflection (the optical path length difference is the optical path length between the nearest side of the document and the light source, and the farthest side). The difference in the optical path length with the light source).

The Xe tube 2 is attached to the tip of the rack gear 9 in the direction in which the surface of the original is irradiated. The drive circuit 8 is instructed by the CPU 4 to drive the motor 11 with the gear 10
Is driven to move the rack gear 9 and the Xe tube 2. As described above, the position of the Xe tube 2 is determined based on the angle of view and the focus position of the projection lens 6. CPU4 is the motor 1
Based on the rotation amount of 1 and the output from the origin detection means (not shown), the movement amount of the rack gear 9 is obtained and the position of the Xe tube 2 is grasped. When it is determined that the Xe tube 2 has moved to the set position, the driving of the motor 11 is stopped.

The rack gear 9 has an arc shape centered on the center 3a of the original 3. By making the shape of an arc, even if the Xe tube 2 is moved, the center 3a (FIG. 1) of the original 3 and the Xe tube 2
The optical path length of the tube 2 does not change significantly. Also, the rack gear 9
The Xe tube 2 attached to the front end of the drawing moves along an arcuate locus and always faces the document surface.

Since the illumination position changes due to the movement of the Xe tube 2, the optimum amount of emitted light also changes. When reading, Xe
The amount of light emitted from the Xe tube 2 is changed depending on the position of the tube 2. The amount of emitted light can be set by preparing a table corresponding to the angle of view and the focus position in advance and using it. Also,
In addition to changing the amount of emitted light, changing the gain value of CCD 1,
By changing the shading correction data, it is possible to deal with the change in the reflected light amount accompanying the change in the illumination position. These values are also set corresponding to the position of the Xe tube 2. The change of each value is performed by the instruction of the CPU 4.

Further, after the illumination position is changed and before the reading operation is started, the Xe tube 2 is made to emit light once to read the reflected light into the CCD 1, and the light emission amount of the Xe tube 2, C, is read based on this data.
You may set the gain value of CD1, and shading correction data. By adopting this method, it is possible to cope with a change in reflectance due to a difference in paper quality of the document, and it is possible to illuminate the document with a more appropriate light amount.

Focusing of the projection lens 6, angle of view adjustment and X
After the alignment of the e-tube 2 is completed, the Xe tube 2 emits light with a predetermined light amount, the CCD 1 captures an image, and C
Transfer to PU4.

Further, since the position of the Xe tube 2 is preset depending on the angle of view and the focus position of the projection lens 6, the position of the Xe tube 2 can be determined even if the operations of adjusting the angle of view and focusing are not finished. it can. Therefore, the Xe tube 2 may be positioned at the same time when the projection lens 6 is focused and the angle of view is adjusted.

Since it is impossible to set the incident angle of the illumination light to 90 degrees, when there is only one illumination light source, there is a difference in the amount of illumination light between a portion far from the illumination light source of the original 3 and a portion near the same. As a result, uneven illumination may occur in the captured image, with bright and dark portions. 4 and 5
As in the second embodiment shown in, two Xe tubes 2 are provided,
Illuminating the original 3 from two directions can reduce uneven illumination. By combining the gears 13, 14, the pulley 15, the belt 16 and the like, it becomes possible to move the two illumination light sources with only one motor 11. However, FIG.
Also, the gear 14, the pulley 15, the belt 16 and the like in FIG.
The original 3 should be attached at a position where the irradiation light is not blocked.

There is also a method of irradiating from two directions without using a belt or the like, as in the third embodiment shown in FIGS. 6 and 7. In this case, the two rack gears 9 are attached so that the gear 10 is vertically sandwiched. In order to make the incident angles of the two Xe tubes 2 on the original 3 equal, the motor position is displaced in the horizontal direction from the center of the original. However, the motor 11 is attached to a position where the irradiation light on the original 3 is not blocked. Although the gear 10 and the rack gear 9 are located within the range of reflection in the image, the reflection can be prevented by processing the gear 10 and the rack gear 9 into black with low reflectance.

In the first to third embodiments, the case where the rack gear 9 has a circular arc has been described. However, as in the fourth and fifth embodiments shown in FIGS. 8 and 9, the rack gear 9 is used. May be linear. In the fourth embodiment shown in FIG. 8, a linear rack gear 9 is obliquely attached to the original surface so that the Xe tube 2 faces the original 3. The rack gear 9 is linearly moved by the motor 11. The position of the Xe tube 2 in this case is set in advance by the angle of view and the focus position of the projection lens 6 as in the case of the first to third embodiments described above, and the motor 11
To move to the set position.

In the fifth embodiment shown in FIG. 9, a linear rack gear 9 is arranged so as to move parallel to the document surface. In this case, the tip of the rack gear 9 is bent so that the Xe tube 2 faces the original 3 and the Xe tube is bent at the bent portion.
Install tube 2.

Also in the fourth and fifth embodiments, X
It goes without saying that the e-tube 2 is arranged outside the reflection range. In the first to fifth embodiments, the case where the Xe tube 2 is used as the light source has been described.
The light source is not limited to the e-tube 2 and may be another light source.

[0023]

As described above, according to the document illuminating device and the image input device of the present invention, the moving amount of the moving means for moving the light emitting means is controlled based on the angle of view and the focus position of the image forming means. Since this is done, it is possible to prevent the reflection of the light emitting means in the image and provide effective illumination.

[Brief description of drawings]

FIG. 1 is a first of a document illumination device and an image input device of the present invention.
2 is an explanatory front view showing the configuration of the embodiment of FIG.

FIG. 2 is an explanatory diagram showing the position of the Xe tube when the projection lens of FIG. 1 has a wide angle of view or a far focus.

FIG. 3 is an explanatory diagram showing the position of the Xe tube when the projection lens of FIG. 1 has a narrow field angle or near focus.

FIG. 4 is an explanatory front view showing the configuration of the second embodiment of the present invention.

FIG. 5 is a plan view of FIG.

FIG. 6 is an explanatory front view showing the configuration of the third embodiment of the present invention.

FIG. 7 is a plan view of FIG. 6;

FIG. 8 is an explanatory front view showing the configuration of the fourth embodiment of the present invention.

FIG. 9 is an explanatory front view showing the configuration of the fifth embodiment of the present invention.

[Explanation of symbols]

 1 CCD (photoelectric conversion means) 2 Xe tube (light emitting means) 3 document 4 CPU (control means) 6 projection lens (imaging means) 9 rack gear (moving means)

Claims (7)

[Claims] 1. A document illuminating device comprising a light emitting means for illuminating a document and an image forming means for forming an image of illumination light from the document at a predetermined position, wherein the light emitting means is not reflected in the image forming means. An original illuminating device, characterized in that a moving means for moving the light emitting means is provided at a position. 2. The document illumination device according to claim 1, wherein the moving unit rotates the light emitting unit in an arc shape around a center of a document table on which the document is placed. 3. The document illuminating apparatus according to claim 1, wherein the moving unit moves the light emitting unit linearly in a parallel or oblique direction with respect to a document table on which the document is placed. 4. The document illumination device according to claim 1, wherein a plurality of the light emitting means and the moving means are arranged on the outer periphery of the document. 5. The document illumination device according to claim 1, further comprising control means for positioning and controlling the light emitting means at a predetermined position by the moving means. 6. The document illumination according to claim 5, wherein the control unit controls the position of the moving unit based on at least one of an angle of view and a focus position of the image forming unit. apparatus. 7. A light emitting means for illuminating a document, a photoelectric conversion means for entering illumination light from the document and converting it into an electric signal, and an image for forming the illumination light from the document on the photoelectric conversion means. An image input device comprising an image means, comprising the document illumination device according to any one of claims 1 to 6.