JPH08130613A - Scanner - Google Patents

Abstract

PURPOSE: To compensate a phase fluctuation in an output signal of an A/D converter due to mismatching of the number of revolutions between 1st and 2nd disks. CONSTITUTION: A motor 10 drives a common center shaft 4 to drive 1st and 2nd disks 2, 8 simultaneously. A motor 26 and a screw 28 are used to drive a slide support 12 linearly in the radial direction of the 1st and 2nd disks. An image detection means 18 provided to the 1st support 14 reads optically the original of the image and converts the image into an electric signal. A marker detection means 36 arranged on an outer circumferential part of the 1st disk reads optically a marker 34 and converts it into an electric signal. A pattern detection means 24 provided to a 2nd support section 16 reads a prescribed pattern on a spiral track optically and converts it into a read electric signal. A phase comparator means compares the phase of an output signal of the marker detection means 36 with that of a pattern detection means 24, and a phase control means controls the phase of a clock signal of an A/D converter of the phase of an output signal of the A/D converter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanner device, and more particularly to a scanner device suitable for accurately and inexpensively reading high definition image information from an image original.

[0002]

2. Description of the Related Art A typical configuration of a conventional scanner device is called a flat bed type (flat plate type), in which an image original is placed on a flat original table and light is scanned from the back side or front side of the original, Charge-coupled device (C
The image information is read by receiving with a photodetector such as a CD). In this method, the pixel density of the CCD is limited, and the scanning drive accuracy of the light source and the photodetector is also limited, so that it is difficult to increase the reading resolution.

As a conventional example of a high-definition scanner device,
A device called a drum type (cylindrical type) is also known. This is a photodetector that attaches a film-shaped image document on the surface of a cylindrical transparent rotating structure, arranges a light source on the rotation axis of the cylindrical rotating structure, and slides in parallel with the rotation axis in correspondence with this light source. Set up a vessel. By moving the light source and the photodetector along the rotation axis while rotating the cylindrical rotary member, the image information of the film-shaped original is scanned and read with high accuracy. In the case of this device, the image reading accuracy mainly depends on the accuracy of the position control of the light source and the photodetector. This position control mechanism supports a slender rotatable screw in parallel with the rotation axis of the cylindrical rotary structure, and by rotating this screw with a motor, the holder of the photodetector engaged with the screw is cylindrical. Move it parallel to the axis of rotation of the rotating structure. In order to realize high-definition scanning, the holder of the photodetector must move in proportion to the rotation angle of the motor, but there is a limit to the mechanical finishing accuracy of the long and thin screws, and it is about several tens of microns. The error was unavoidable. Further, in order to form a highly accurate screw, there is a problem that a sophisticated mechanical processing technique is required and the device is relatively large, resulting in a high manufacturing cost.

The applicant of the present application has proposed, in Japanese Patent Application No. 6-73899, an inexpensive scanner device which can solve the above problems and can accurately read a high-definition image. 5 and 6 are simplified perspective and side views of the scanner disclosed in this patent application. Incidentally, in FIG. 6, a part of the disc is omitted. The first disk 2 is made of, for example, glass or another transparent material, and is supported by a rotatable common central shaft 4. Four image originals 6 such as slide photographs are attached to the upper surface of the first disc 2 by an appropriate means (gluing or the like). A second disk 8 having spiral tracks engraved on its upper surface is likewise supported on a common central axis 4. This spiral track is a copy of a master disk track formed by laser cutting in a well-known mass-production process, and is equivalent to that formed on the surface of a well-known compact disc, laser disc, or the like. It is a thing. The track of the second disk 8 is for accurately scanning the image original set on the first disk 2, as described later.

The spiral track of the second disk 8 has extremely high precision, and a digital signal having a predetermined pattern is engraved on the convex portion between adjacent tracks. Distance between adjacent tracks of this spiral track (track pitch)
Is, for example, about 1.6 μm (microns). A spindle motor 10, which is a rotation driving means, is coupled to the lower end of the common central shaft 4, and the first and second disks 2 and 8 are coaxially rotated together with the common central shaft 4 by the rotational driving force of this motor. A U-shaped slide support structure 12 is provided so as to be slidable in the radial direction of the first and second disks 2 and 8 (the slide support mechanism is not shown). The slide support structure 12 has two arm-shaped support portions 14 and 16. A photodetection unit (image detection means) OD18 that optically reads the image original 6 and converts it into an electric signal is provided below the support unit 14. Further, an optical pickup (pattern detecting means) OP for tracing a spiral track on the surface of the second disk 8 for optically reading a specific pattern and converting it into an electric signal is provided below the supporting portion 16. .

Further, a light source L is provided on the second supporting portion 16.
Provide S20. The output light from the light source 20 passes through the first disk 2 and the image original 6 and supplies the electric signal of the image detected by the photodetector 18 to the control circuit 22. Although FIG. 5 and FIG. 6 show a method of detecting transmitted light, depending on the type of image original, the light source 20 and the light detection unit 1 may be used.
8 and 8 may be arranged on the same side, and the reflected light of the light from the light source may be detected. In that case, it is not necessary to form the first disk 2 with a transparent material.

The optical pickup 24 provided under the second support 16 irradiates a laser beam on a spiral track on the surface of the second disk 8 and detects the reflected light to trace accurately. Therefore, a predetermined pattern signal is supplied to the control circuit 22. The control circuit 22 includes a spindle motor 26 for rotating the disks 2 and 8.
And a slide motor 26 for linearly driving the slide support structure 12 parallel to the disk. The rotary shaft of the slide motor 26 is coupled to one end of a slide mechanism screw 28, and the other end of the slide mechanism screw 28 is screw-engaged with the slide support structure 12. Therefore, the position of the slide support structure 12 can be moved along the radial direction of the disks 2 and 8 according to the rotation of the slide motor 26. The slide motor 26 and the slide mechanism screw 28 serve as a linear drive means.

The control circuit 22 includes a microprocessor, a ROM in which a program is stored, and an RA as a storage means.
M, a driver circuit for controlling the motor, and the like. The spiral track carved on the surface of the second disk 8 contains a predetermined pattern (for example, bit clock information) which is rotation control information corresponding to a predetermined frequency. Therefore, the control circuit 22 receives the output signal of the predetermined pattern from the optical pickup 24, but the motor 1 is controlled so that the frequency (or cycle) of the pattern becomes a desired value.
By controlling 0 and 26, the photodetection section 18 can be controlled so as to accurately scan each of the image originals 6. The tracks for scan control are provided on the second disk 8 because the first disk 2 is transparent.

In this way, the control circuit 22 servo-controls the slide motor 26 to trace the exact spiral track on the second disk 8, thus mechanically controlling the slide control mechanism including the slide mechanism screw 28. The accuracy is
It doesn't have to be that high. Therefore, the manufacturing cost can be significantly reduced.

[0010]

The scanner device shown in FIGS. 5 and 6 is premised on that the disks 2 and 8 perform the same rotation in perfect alignment. However, if the image original 2 has a certain size, the radii of the first and second disks must be increased accordingly. On the other hand, in order to remove the image original 2, the first disk 2 can be removed from the common central shaft 4. Therefore, depending on how the first disc 2 is attached, the first disc 2 may be slightly eccentric with respect to the common central axis 4. Further, since the disc is thin, when the disc becomes large, the outer side may bend due to rotation. In such a case, the premise that the disks 2 and 8 rotate completely in the same rotation is broken, and even this scanner device cannot perform accurate scanning.

Therefore, an object of the present invention is to provide a scanner device which is inexpensive and can perform more accurate scanning.

[0012]

The scanner device of the present invention is an improvement of the device shown in FIGS. 5 and 6.
The first disk 2 is attached to a rotatable common central shaft 4, has a marker 2 on the outer peripheral portion, and an image original 6 is placed on the first disk 2. The second disk 8 is attached to the common central shaft 4 and has a track of a predetermined pattern spirally formed on one surface. The rotation driving means 10 rotates the common central shaft 4 to rotate the first and second disks simultaneously. The slide support structure 12 which is linearly movable in the radial direction of the first and second disks includes a first support portion 14 and a second support portion 16. The first support portion is arranged near the main surface of the first disc, and the second support portion is arranged near one main surface of the second disc. The linear drive means 26, 28 are
The slide support structure 12 is linearly driven in the radial direction of the first and second disks. The image detecting means 18 is provided on the first supporting portion 14, optically reads the image original on the main surface of the first disk, and converts it into an electric signal. The marker detecting means 36 is fixedly arranged in the vicinity of the outer peripheral portion of the first disk, optically reads the marker of the first disk, and converts it into an electric signal. The pattern detection means 24 includes the second support portion 1.
6, a predetermined pattern of the spiral track is optically read and converted into an electric signal. Phase comparison means 50
Compares the phases of the output signals of the marker detecting means 36 and the pattern detecting means 24, and the analog / digital converter 56 converts the output signal of the image detecting means 18 into a digital signal. The phase control means 54 controls the phase of the clock signal of the analog-digital converter or the phase of the output signal of this analog-digital converter according to the comparison result of the phase comparison means. Therefore, it is possible to compensate the phase fluctuation of the output signal of the analog-digital converter due to the discrepancy in rotation of the first and second disks.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIGS. Since the present invention is similar to the scanner device of the present applicant described with reference to FIGS. 5 and 6, the same portions are denoted by the same reference numerals, the description thereof will be omitted, and only different portions will be described.

FIG. 1 is a perspective view of a preferred embodiment of the scanner device of the present invention, and FIG. 2 is a side view thereof. In addition,
In FIG. 2, the left side of the disc is omitted. First
A circular predetermined marker 34 is provided on the outer periphery of the disk 2. The marker 34 is, for example, a band-shaped marker in which white and black areas are alternately arranged. An opening 30 is provided in the first support portion 14 of the slide support structure 12, and a support rod 32 is inserted into the opening 30. At the tip of the support rod 32, a photodetector unit 36 that optically reads the band-shaped marker 34 and converts it into an electric signal is provided. The light detection unit 36 and the marker 34 may be the same as the rotary encoder technology. The light detection unit 36 is fixed to the scanner device main body (not shown) so that it is always above the band-shaped marker 34. Since the support rod 32 passes through the elongated opening 14 of the first support portion 14, the slide support structure 12
Note that it is always fixed in place, regardless of the slide in.

The control circuit 23 receives the output signal of the photo-detecting section 36, and has the same function as the control circuit 22 of FIG. 6 and also another function for the present invention. FIG. 3 is a block diagram of a part of the control circuit 23 according to the first embodiment. As described above, the output signal of the optical pickup 24 is used for controlling the spindle motor 10 and the slide motor 26, and is also supplied to the phase comparator 50. The output signal of the second photodetecting section 36 indicating the rotation state of the outer peripheral portion of the first disk 2 is also supplied to the phase comparator 50. The output signal of the optical pickup 24 is a high frequency pulse, while the output signal of the photodetector section 36 is a low frequency pulse. Phase comparator 50
Compares the phases of the high-frequency pulse and the low-frequency pulse to determine whether the rotation of the first disk 2 and the rotation of the second disk 8 have a constant relationship.

Analog-to-digital (A / D) converter 56
Is a signal from the first photo-detecting section 18, which is an image detecting means, at the time of rising (or falling) of the clock signal supplied from the sampling clock generator 52 via the variable delay circuit (phase control means) 54. The image signal is converted into a digital signal. This digital signal is supplied to a utilization device such as a computer as an output signal of the scanner device. The delay time of the variable delay circuit 54 is controlled by the output signal of the phase comparator 50.

Next, the operation of FIG. 3 will be described. When the relative rotation speed of the first disk 2 with respect to the second disk 8 is increased due to the eccentricity or the deflection of the first disk 2, the phase comparator 50 shortens the delay time of the variable delay circuit 54. Therefore, the interval between conversion points (sampling points) of the A / D converter 56 is temporarily shortened, which is equivalent to conversion of a video signal into a digital signal at equal intervals. Similarly, when the relative rotation speed of the first disk 2 with respect to the second disk 8 becomes slow, the phase comparator 50 causes the variable delay circuit 54 to move.
Increase the delay time of. Therefore, the conversion interval of the A / D converter 56 is temporarily lengthened, and in this case also, it is equivalent to converting the video signal into a digital signal at equal intervals.
Note that the relationship between the phase difference detected by the phase comparator 50 and the delay time of the variable delay circuit 54 is such that the A / D
The sampling intervals of the digital signals from the converter 56 are equal.

FIG. 4 is a block diagram of another embodiment of a part of the control circuit 23. This block diagram is similar to FIG. 3 except that the position of the delay circuit 54 is on the output side of the A / D converter 56. Also in this case, the operation is similar to that in FIG. However, the number of channels of the delay circuit 54 is 1 in the case of FIG. 3, but it is A / D converter 56 in the case of FIG.
Is the number of output bits.

Although the above has described only the preferred embodiments of the present invention, various modifications can be made without departing from the gist of the present invention. For example, the marker newly provided on the first disc may be a marker having irregularities instead of the white and black band-shaped markers.

[0020]

As described above, according to the present invention, it is possible to easily compensate for the phase fluctuation of the output signal of the A / D converter due to the non-coincidence of the rotation of the first and second disks. It is possible to provide a scanner device capable of performing the above.

[Brief description of drawings]

FIG. 1 is a perspective view of a preferred embodiment of a scanner device of the present invention.

FIG. 2 is a side view of a preferred embodiment of the scanner device of the present invention.

FIG. 3 is a block diagram of a first embodiment of a part of a control circuit used in the scanner device of the present invention.

FIG. 4 is a block diagram of a second embodiment of a part of a control circuit used in the scanner device of the present invention.

FIG. 5 is a perspective view of a scanner device according to the present invention.

FIG. 6 is a side view of a scanner device according to the present invention.

[Explanation of symbols]

 2 1st disk 8 2nd disk 10 Rotational drive means 12 Slide support mechanism 14 1st support part 16 2nd support part 18 Image detection means 24 Pattern detection means 26, 28 Linear drive means 36 Marker detection means 50 Phase comparison means 54 Phase Control means 56 A / D converter

Claims (1)

[Claims] 1. A first disk, which is mounted on a rotatable common central axis, has a marker on its outer periphery, and on which an image original is arranged, and a track having a predetermined pattern, which is mounted on the common central axis, is one of A second disk spirally formed on the surface, a rotation driving means for rotating the common central axis, a first support portion near the main surface of the first disk, and the one main surface of the second disk And a slide support structure which has a second support portion in the vicinity of and is linearly movable in the radial direction of the first and second discs, and the slide support structure is linearly driven in the radial direction of the first and second discs. Linear drive means, image detecting means provided on the first support portion for optically reading the image original on the main surface of the first disk and converting it into an electric signal, and in the vicinity of the outer peripheral portion of the first disk. Fixed to Marker means for optically reading the marker of the first disk and converting it into an electric signal, and a predetermined pattern of the spiral track provided on the second support portion. Pattern detecting means for converting into electric signals, phase comparing means for comparing the phases of the output signals of the marker detecting means and the pattern detecting means, and analog / digital conversion for converting the output signals of the image detecting means into digital signals And the analog / digital converter according to the comparison result of the phase comparator.
Phase control means for controlling the phase of the clock signal of the digital converter or the phase of the output signal of the analog-digital converter, the output of the analog-digital converter due to the discrepancy in rotation of the first and second disks A scanner device characterized by compensating for phase fluctuations of a signal.