JP2002328322A - Optical scanner and method for dividing scan lane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply and precisely divide a scanning range in optical scanning. SOLUTION: A lane division standard film 40 is arranged at a scanning position of a laser beam 12. A lane division mark 41 of this lane division standard film 40 is read. A position specifying signal is outputted to an LMC address counter 27 based on this read signal. At the LMC address counter 27, a clock from a pulse generation circuit 26 is counted by a start pulse from a standard position detecting device 19. The calculated value is stored in a memory 28 as an address data of the lane division signal based on the position specifying signal input from a comparator 23. A lane break signal (LMC) is generated at an LMC generating device 29 based on the address data stored in this memory 28. A variety of patterns of lane division is simply and can be precisely performed, since the lane is divided by each lane division mark 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning lane dividing method and an optical scanning device for freely dividing a scanning area when scanning a light beam by a rotary polygon mirror.

[0002]

2. Description of the Related Art In order to inspect a running web for surface defects, a method of scanning a light beam in the width direction of the web and inspecting the presence or absence of a surface defect based on reflected light or transmitted light is known. Have been. In such a case, a rotating polygon mirror is used for scanning the light beam, but it is necessary to specify a defect detection position in the width direction of the web. That is, it is necessary to spatially divide the web into several lanes in the width direction of the web and to know which lane the defect detected during one scanning is to belong to .

In order to spatially divide a scanning lane,
Conventionally, an electric reference pulse at a constant interval is generated, the frequency is divided in synchronization with the timing of the start of scanning, and the divided clock is used to perform lane division at equal time intervals. That is, the variation of the light output from the web surface during each one scanning period is divided for each of the frequency-divided clocks, so that the light output corresponds to the lane position in the width direction of the web.

Further, a beam splitter such as a half mirror is provided between the rotary polygon mirror and the web to split a light beam to be scanned, and one of the beams is irradiated on the web as main scanning light, and the other is used as reference light. There is also a configuration in which light is made incident on a plurality of photodetectors arranged in the scanning direction, and lanes are divided into one scanning region using output signals from the photodetectors.

However, when light beam scanning is performed by a rotary polygon mirror, the scanning speed of the light beam in the width direction of the web is not constant. Accordingly, in order to perform lane division at equal intervals, for example, Japanese Utility Model Application Laid-Open No. 58-120913 and "Design of Laser Scanning Lens"("Optics",
Vol. 10, No. 5, October 1981, p. 348), the scanning speed of the light beam must be made uniform in the width direction of the web by using an fθ lens as shown in
The structure and adjustment are complicated, and the cost is high. In addition, since the lane division is performed on the basis of the frequency-divided clocks at equal time intervals, only lane division at equal intervals can be realized.

On the other hand, in a system in which a divided signal of a scanning lane is obtained by the reference light, photodetectors are required for the number of divided lanes, and the power of the main scanning light is consumed by the use of the beam splitter. The power of the laser must be increased in advance, resulting in a complicated mechanism and disadvantageous cost.

For this reason, the applicant of the present invention has proposed a method of dividing a scanning lane into arbitrary lanes at equal intervals as well as at equal intervals while utilizing a scanning optical system using a rotating polygon mirror (Japanese Patent Application Laid-Open No. HEI 9-163556). 62-294216).

[0008]

However, the above-described lane dividing method involves many trial-and-error factors, and requires a number of operations of writing and checking data in the storage means. In addition, when there are many lane division patterns or when high accuracy is required, the number of steps is enormous, and efficient lane division is difficult.

The present invention has been made to solve the above problems, and
It is an object of the present invention to provide a lane division method and an optical scanning device that can perform high-precision lane division efficiently by one operation.

[0010]

According to a first aspect of the present invention, there is provided an optical scanning apparatus for irradiating an object to be scanned with a light beam by a rotating polygon mirror rotating at a constant speed. A lane division reference sheet in which a plurality of lane division marks are arranged in the scanning direction is arranged at the irradiation position of the light beam, and each lane division mark of the lane division reference sheet is scanned with a light beam, and the transmitted light or the reflected light Is received by a photoelectric element, a signal corresponding to the lane division mark is obtained based on the received light signal, the position information of the signal is stored, and a lane division signal is generated based on the stored position information. Preferably, a plurality of lane division signals are obtained by using a plurality of the lane division patterns, these are stored, and the plurality of lane division signals are selected and used.

According to the third aspect of the present invention, there is provided an optical scanning means for irradiating an object to be scanned with a light beam by a rotating polygonal mirror rotating at a constant speed for scanning, a pulse generating means for generating a reference clock pulse, Counting means for counting the clock pulse; storage means for storing lane division position information specified based on the count value of the counting means for dividing the scanning region of the light beam; Scanning start signal generating means for detecting that a scanning position has been reached and outputting a scanning start signal, and starting counting by the counting means based on the scanning start signal, by this count value and the lane division position information, Lane division signal generating means for obtaining a lane division signal for dividing a scanning region of a light beam, and a light beam transmitted through a scanning object irradiated with the light beam or A light receiving sensor for generating a photoelectric signal by receiving Shako, first for processing photoelectric signals, each lane the divided lane division signal from the light receiving sensor
Signal processing means, and a lane division reference sheet in which a plurality of lane division marks are arranged in the scanning direction at the irradiation position of the light beam, signal processing of a photoelectric signal from the light receiving sensor, and A lane positioning signal corresponding to the division mark is generated, a count value of the counter means is read based on the lane positioning signal, and the lane division position information is obtained based on the count value and the lane positioning signal. Second signal processing means for writing to the storage means. A selection means for selecting the first signal processing means and the second signal processing means is provided, the second signal processing means is selected, and lane division position information is written in the storage means. It is preferable that a signal processing unit is selected to perform signal processing based on the lane division position information stored in the storage unit.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 schematically showing a web inspection apparatus according to the present invention, a web 10 is fed in the direction of arrow X by a conveying roller or the like. In synchronism with this feeding, the laser beam 12 is moved in the width direction of the web 10 by the scanner 11.
Are scanned from left to right in the figure. The scanner 11 includes a laser oscillator 13, a rotary polygon mirror 14, a motor 15, and the like. Laser beam 1 from laser oscillator 13
2 is irradiated toward the rotating polygon mirror 14. The rotating polygon mirror 14 is rotated clockwise in FIG. The drive of the motor 15 is controlled by a controller 17 via a driver 16. Thereby, the laser beam 12 draws a trajectory 18 on the web 10.

The web 1 within the irradiation range of the laser beam 12
A reference position detector 19 is arranged near zero. The reference position detector 19 detects that the laser beam 12
Before starting scanning along the line, the laser beam 12 is detected and a start pulse (scanning start signal) is output. This start pulse is input to the controller 17.

A horizontally long photodetector 20 is provided so as to face the locus 18. The photodetector 20 outputs an electric signal corresponding to the intensity of the laser beam 12 transmitted through the web 10, and the electric signal is input to the controller 17. In the controller 17, an A / D converter 21, a sampling hold filter circuit 22, a comparator 23, a selector 24, an AND circuit 25, a pulse generation circuit 26, an LMC address counter 27, an LMC
An address data memory 28, an LMC generator 29 and the like are provided.

The photoelectric signal from the photodetector 20 is taken into an A / D converter 21, sampled and held by a sampling and holding circuit 22, and filtered to remove a noise signal. The comparator 23 binarizes the signal according to the threshold value. The signal below the threshold value is used as a defect signal or a positioning signal for generating a lane break signal (LMC) described later.
The threshold value is determined by the controller 17 according to the type of defect to be detected and the type of lane division reference film described later.
Is set by

The selector 24 is switched to a defect inspection mode or a lane division setting mode by mode selection. When the defect inspection mode is selected, it is connected to the A side, whereby the defect signal is supplied to the AND circuit 25.
Sent to The AND circuit 25 sends the AND between the LMC from the LMC generator 29 and the defect signal to the defect specifying unit 35 as a defect signal for each lane.

The defect specifying section 35 specifies a defect position in synchronization with the feeding of the web 10. The defect position is specified based on the lane number and the length information of the web in the feeding direction. Further, the defect specifying unit 35 specifies the defect position,
If necessary, the continuity of the defect signal is determined, and based on this continuity, it is also determined whether or not the defect is a wide area defect. The defect position data and defect type data specified in this way are stored in the memory 35a and sent to the defect image processing device 36 online or offline.

The defect image processing device 36 performs data processing based on defect position data and type data. The defect data after this processing is referred to, for example, when processing the film,
It is used so that various defects are not included in the final product. Further, it is used as a cause of a defect or as feedback information of a manufacturing line.

In the lane division setting mode, lane division is set. First, as shown in FIG. 2, the lane division reference film 40 is arranged at the laser beam irradiation position, and the lane division mark 41 is detected in the same manner as the defect detection, and the lane division mark 41 is detected based on the start pulse. Then, the lane division position is specified.
Although the lane division reference film 40 is attached to the web 10 using the adhesive tape 42, the reference film 40 may be installed at the laser beam irradiation position by other various methods.

FIG. 3 shows an example of a lane division pattern.
In the present embodiment, the inspection section ES in the width direction of the web 10 is divided into ten lanes Ln1 to Ln10 by the lane division virtual line LD. In order to obtain such a lane division pattern, as shown in FIG. 2, a lane division reference film 40 having the same division pattern is used.

On the lane division reference film 40, a lane division pattern 43 in which eleven lane division marks 41 are arranged in the scanning direction is recorded. Each lane division mark 41 is composed of a parallel line. As shown in FIG. 3, the inspection section ES is divided into ten lanes Ln1 to Ln10 by the eleven lane division marks 41.
Note that a plurality of types of lane division reference films 40 are prepared corresponding to the inspection target. For example, a lane division reference film 4 in a device for inspecting a density defect or the like.
In the case of 0, the lane division pattern 43 is constituted by the mark 41 having the density detected in the same manner as the density defect. In the case of a lane division mark in an apparatus for inspecting a surface flaw or the like, a lane division pattern is formed using a groove or the like detected in the same manner as a flaw defect.

The lane division pattern 43 of the lane division reference film 40 is scanned by the laser beam 12, the transmitted light is detected by the photodetector 20, and the detection signal is converted to A / A.
The noise is removed and digitized by passing through a D converter 21 and a sampling hold filter circuit 22, and this signal is compared with a threshold value by a comparator 23,
A positioning signal is output when the signal is equal to or smaller than the threshold value. This positioning signal is sent to the LMC through the selector 24.
The address is input to the address counter 27.

The LMC address counter 27 has a start pulse and a pulse generation circuit 2 in addition to the positioning signal.
6 is input. The LMC address counter 27 counts the clock from the pulse generator 26 at the rise of the start pulse, and outputs the count value at the rise of the positioning signal from the comparator 23. This count value is sent to the LMC address data memory 28.

FIG. 4 is a timing chart of the signal processing. 1 correspond to the signals in the respective parts of FIG. 1, は denotes an output from the photodetector 20, は denotes an output from the sampling and holding filter circuit 22, は denotes an output from the comparator 23, and は denotes an LMC. The output from the address counter 27 is shown.

In the LMC address data memory 28, L
The count values of the MC address counter 27 are associated with the lane numbers thereof, and the clock count values “A” to “J” of each LMC are stored. Thus, the lanes Ln1 to Ln10 are specified based on the lane division reference film 40.

In the defect inspection mode, the controller 17
Specifies the lane break position based on each data from the LMC address data memory 28. For this reason, LMC
The address counter 27 starts counting the clock in response to the rising signal of the start pulse, and the LMC generator 29 compares the count value with the position data in the LMC address data memory 28. When they match, it is determined that the position is a lane break position, and an LMC is issued.

Next, the operation of this embodiment will be described with reference to the flowchart of FIG. First, the lane division setting mode is selected. By this selection, the selector 24 is switched to the B side. Next, as shown in FIG. 2, the lane division reference film 40 is arranged at the inspection position of the web 10. This arrangement is performed by attaching a lane division reference film 40 to the web 10 with an adhesive tape 42 or the like.

Next, as shown in FIG.
The laser beam 12 is applied to the lane division reference film 40 by driving the motor 3 and the motor 15, and the transmitted light of the laser beam 12 is read by the photodetector 20. The controller 17 calculates the average value PMTave (= (PMTmax + PMTmin) / based on the maximum value PMTmax and the minimum value PMTmin from the photodetector 20.
2) is calculated, and this is set as a threshold. And A / D
The output signal from the converter 21, the sampling and holding and filter circuit 22 is compared with the threshold value. I do.

A start pulse and a clock are input to the LMC address counter 27 in addition to the positioning signal, and the position of each lane division mark is specified by the count number of the clock based on the start pulse based on the positioning signal. You. The specified position data is LM
The data is written to the C address data memory 28. As described above, for the necessary lane division pattern, the position of each lane division mark 41 is specified as in the case of defect detection using the reference film 40 on which the lane division pattern 43 is recorded.

When the defect inspection mode is selected, the selector 24 is switched to the A side by this selection. Next, the laser oscillator 13 and the motor 15 are driven to irradiate the web 10 with the laser beam 12, and the transmitted light of the laser beam 12 is detected by the photodetector 2.
Read by 0. Then, the output signals from the A / D converter 21 and the sampling hold filter circuit 22 are compared with the threshold value, and when the output signal is equal to or less than the threshold value, it is determined that the signal is defective. At this time, the clock is counted by the counter 27 based on the start pulse, and the LMC
The count value is compared with the data in the LMC address data memory 28 by the generator 29. Then, when the data matches, the LMC is output. With the output of the LMC, a defect position is specified for each lane in the web width direction.

The LMC thus obtained is used, for example, as shown in FIG. FIG. 6 is an example of the evaluation waveform 50 obtained corresponding to the magnitude of the electric signal from the photodetector 20. This evaluation waveform 50 is obtained by
The range of the number of scans, that is, the transmitted light amount when the web 1 is scanned over the entire width is shown. By displaying the lane number together with the evaluation waveform 50, it is possible to clearly identify in which lane within the width of the web 10 the defective portion 50a found in the evaluation waveform 50 is located. Further, the defect position is specified in the web feed direction based on the scan position data (the feed amount of the web 10). For example, in the case of FIG. 6, it is specified that a density defect exists in the seventh lane based on a change in the amount of transmitted light in the n-th scan.

In the above embodiment, the inspection section E of the web 10
Although a method for obtaining a lane division signal that divides S into ten has been described, the number of lane divisions, the width of each lane, and the like may be appropriately changed. In this case, a lane division reference film on which a pattern to be a desired lane division is recorded is prepared, and the lane division reference film is arranged at the irradiation position of the laser beam, and each lane division mark is detected in the same manner as a defect. This lane division mark position is specified in the same manner as in the embodiment. By specifying each lane position in advance by using such different lane division patterns, storing them in a memory, and selecting a lane division pattern as necessary, a defect can be detected by various lane division patterns. .

In the above embodiment, the present invention is applied to an inspection apparatus that detects a defect based on transmitted light of a web. However, the present invention is not limited to this, and the present invention is applied to an apparatus that inspects a defect based on reflected light of a web. You may. Further, as long as the device performs optical scanning, the present invention is not limited to the defect inspection device, and may be implemented in another device. For example, the lane dividing method of the present invention may be implemented in an image reading device that reads an image by optical scanning.

[0034]

According to the present invention, a lane division reference sheet formed by arranging a plurality of lane division marks in the scanning direction is arranged at the irradiation position of the light beam, and each lane division mark of the lane division reference sheet is assigned to the light beam. Scanning, receiving the transmitted light or reflected light by the photoelectric element, obtaining a signal corresponding to the lane division mark based on the received light signal, storing the position information of this signal, and based on the stored position information. Since the lane division signal is generated, it is not necessary to determine the lane division position by trial and error, and the lane can be divided easily and accurately. Also,
By obtaining a plurality of lane division signals using a plurality of the lane division patterns, storing them, and selecting and using the plurality of lane division signals, the lane division pattern can be easily changed. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic configuration of a web inspection device embodying the present invention.

FIG. 2 is a front view showing a state where a lane division reference film is arranged at a laser beam irradiation position.

FIG. 3 is a front view showing an example of lane division.

FIG. 4 is a timing chart showing an example of a signal waveform in each section of FIG.

FIG. 5 is a flowchart illustrating lane division processing.

FIG. 6 is an explanatory diagram showing an example of an evaluation waveform for specifying a defect by a lane number.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 web 11 scanner 12 laser beam 13 laser oscillator 14 rotating polygon mirror 17 controller 20 photodetector 40 lane division reference film 41 lane division mark 43 lane division pattern LD lane division virtual line

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2F065 AA49 BB13 BB15 BB22 CC02 DD19 FF23 FF44 GG04 HH04 HH15 JJ01 LL15 LL62 MM03 MM16 QQ23 QQ51 UU06 UU07 2G051 AA41 AB02 BA10 BC06 CA01 CB01 EA02 BA03 CA82 CA97 DA31

Claims (4)

[Claims] 1. An optical scanning apparatus for irradiating a scanning object by irradiating a scanning object with a light beam by a rotating polygon mirror rotating at a constant speed, comprising: a lane division reference sheet in which a plurality of lane division marks are arranged in a scanning direction; The lane division mark on the lane division reference sheet is scanned with a light beam, and the transmitted light or the reflected light is received by a photoelectric element, and a signal corresponding to the lane division mark is received based on the received light signal. And storing the position information of the signal, and generating a lane division signal based on the stored position information. 2. A lane division signal having a plurality of different patterns is obtained by using a lane division reference sheet in which the position of the lane division mark is changed, these are stored, and the lane division signals of these different patterns are selected. 2. The method for dividing a scanning lane according to claim 1, wherein the scanning lane is divided. 3. An optical scanning means for irradiating an object to be scanned with a light beam by a rotating polygonal mirror rotating at a constant speed for scanning, a pulse generating means for generating a reference clock pulse, and counting this clock pulse. Counting means; storage means for storing lane division position information specified based on the count value of the counting means for dividing the scanning region of the light beam; and that the light beam has reached a reference scanning position. Scanning start signal generating means for detecting a scanning start signal, and starting counting by the counting means based on the scanning start signal, and by using the counted value and the lane division position information, scans a light beam scanning area. A lane division signal generating means for obtaining a lane division signal for division, and receiving and transmitting light or reflected light of the object to be scanned irradiated with the light beam; A light receiving sensor for generating a signal; first signal processing means for processing a photoelectric signal from the light receiving sensor for each lane divided by the lane division signal; In a state where the lane division reference sheet in which the marks are arranged in the scanning direction is arranged, the photoelectric signal from the light receiving sensor is signal-processed,
A lane positioning signal corresponding to the lane division mark is generated, a count value of the counter means is read based on the lane positioning signal, and the lane division position information is obtained based on the count value and the lane positioning signal. And a second signal processing means for writing the data into the storage means. 4. A selecting means for selecting the first signal processing means and the second signal processing means, selecting the second signal processing means and writing lane division position information in the storage means, 4. The optical scanning device according to claim 3, wherein the first signal processing unit is selected and the signal processing is performed based on the lane division position information stored in the storage unit.