JPS61139703A - Apparatus for detecting pinhole - Google Patents

Abstract

PURPOSE:To conserve labor while eliminating a detection mistake, by calculating positional information by detecting a pinhole on the basis of the image signal from the detection part arranged on the arm mechanism which is set on a stand for illuminating an objective film from below and can move to directions X, Y on the stand. CONSTITUTION:The entire surface of a negative film 1 is scanned by a line sensor camera 9 cooperated with the movement of a large arm 6 and a small arm 7 and the light from a light source 3 is received through the negative film 1 while the quantities of transmitted lights in a blackened part and a transparent part are detected and binarized to be stored in three-line buffer memory 32. If image information is 1, a picture element is a transparent part and, because there is possibility for a pinhole, the address of the picture element is stored and peripheral eight picture elements are called out. If all of picture elements are 0, the objective picture element is discriminated as a pinhole. When the value of a counter exceeds N as the result of the successive counting of the transparent parts of peripheral picture elements, the objective picture element is discriminated as a character or line other than a pinhole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a pinhole detection device that automatically detects pinholes that occur in blackened portions of lithographic films used in photolithography, particularly negative films.

[Prior art and its problems]

In the photoengraving process, a squirrel-shaped negative-positive film is generally used for single-mount exposure work and film reversal work. In this process, pinholes that occur in the blackened areas of the negative film can cause problems in the next process, so pinholes are detected visually and each point is removed using an opaque pen or brush. It is necessary to apply it manually.

Even with A-3 size negative film, there will be hundreds of pinholes, so be sure to remove them (
Currently, only six people have to do the work of discovering and painting, which results in a lot of loss in the photoengraving process (automation is desired).

In addition, the causes of pinholes are dust and minute dirt adhering to the film, and variations in the development state of the film have a large negative side, so it is realistically difficult to prevent pinholes from occurring at all. It is.

As a result, the work of discovering pinholes and painting them over has been considered inefficient and one-man-intensive work that cannot be omitted in the photolithography process.

[Purpose of the invention]

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a pinhole detection device that automatically detects pinholes on a film.

[Summary of the invention]

In order to automatically detect pinholes that occur on a film, the present invention sets the target film on a mount that illuminates from below, and places the film on an arm mechanism that can move on the mount in the X and Y directions. A detection unit is installed, and based on the image signal from the detection unit, it is determined whether or not a pinhole exists on the film. If a pinhole exists, the position information of the pinhole on the film is obtained. It is a device.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an external view showing the basic configuration of one embodiment of the pinhole detection device of the present invention.

The operator selects the negative film 1 to be used for pinhole detection.
1+ is set on the translucent stand (2) at the top of the main body (4). At this time, in order to maintain a constant setting position of the negative film, a mark such as a register mark or a hit mark may be placed on the mount (2), or a pin system may be used for positioning. A light source (3) is provided below this pedestal (2), and the light diffused by the semi-transparent pedestal illuminates the negative film il+ from below. Here, the light source (3) is preferably a direct current lighting fluorescent lamp or the like in consideration of changes in light amount and surface unevenness.

In addition, the surface unevenness will be reduced by the diffusion effect of the pedestal.

The large arm (6) located above the pedestal (2) is connected to the pedestal (2).
2) rail +t21 (
12+, and is configured to be movable in the direction of arrow Y.

A small arm (7) is attached to the large arm (6) so as to be movable in its longitudinal direction (X direction).
7) is equipped with a line sensor camera (9) as an optical sensor facing the pedestal (2), and a large arm (6).
and the line sensor camera (9) by moving the small arm (7).
), it is possible to scan the entire surface of the negative film fi+. For the movement of the large arm (6) and small arm (7), 1.For example, the torque generated by the drive unit 18X81' consisting of a combination of a DC servo motor and an encoder is applied to a ball shaft, rack/binion, or tensioner. This is done by transmitting information using a combination of wires and pulleys.

In addition, the line sensor camera (9) uses negative film fi.
It receives the light from the light source (3) via + and converts it into an electrical signal according to the amount of light received, and it is used as a negative film (1).
The entire surface of the negative film (1) is scanned to detect the amount of transmitted light in the blackened part and the transparent part and binarized to obtain image information of the negative film (1).

Also, as mentioned above, as an optical sensor.

A line sensor such as COD1MO8 is suitable.

This is because the pinhole on the negative film (1) that is the object of detection is extremely small, with a diameter of 30 μm to several 100 μm. This is because it is superior to known detection means.

For example, if you try to process the entire surface of A4 size negative film with pixels of 50 μmφ, the total number of pixels handled will be 69.
3 million pieces. Here, the line sensor is 1.024
bit, IMH2 drive, gap between lines (continuous scanning) 1 m5ec, large arm return time 3 seconds, input is possible in about 2 minutes 40 seconds.

However, with an area sensor of 480 x 380 pixels, the feeding interval of the large arm is 1 second, the return time is 3 seconds, and the feeding time for one screen is 1/30.
In terms of seconds, this is a little over 6 minutes, which is inferior to the line sensor.

In addition, (5) is the operation panel, and the line sensor camera (9
) on the mount in the X and Y coordinate system, numerical keys to enter the size of the negative film, and instruction buttons to start and stop the pinhole detection operation. There is.

FIG. 2 shows a block diagram of a processing circuit that detects pinholes based on image information input from the line sensor camera (9). The image information input by the line sensor camera (9) is converted into digital data by the A/D converter 01), and then transferred to the 5 line buffer memory C.
3]). The line sensor camera (9) is controlled by a camera control circuit (g), and the camera control circuit C351 is operated by a signal from the CPU133. In addition, the 5-line buffer memory C3υ is the CPU
(It is controlled by the memory control (to) which operates based on the signal from 33.

The CPU (G) sequentially imports image information from the ROM (according to the pinhole identification program stored in the 361, 6-line password memory!j C3]), determines whether or not there is a pinhole, and identifies the pinhole. If a pinhole is found, the position information of the pinhole is determined, and this is stored in a pinhole address memory (37) such as a RAM, and after the scanning is completed, it can be displayed by the operator on a CRT display or the like as an output means (41). or record it on a storage medium such as a floppy disk for later automatic smearing processing.

Also, CPtJ (33 is the movement of the line sensor camera (9)).

It is also in charge of control such as stopping, and gives drive and stop signals to the servo motors of the large arm drive section (8) and small arm drive section (8)' through the xy position control circuit (to), and Large arm drive section (8), small arm drive section (8Y
From there, pulse signals from the encoders corresponding to the amount of rotation are returned to the XY position control circuit (to), and by counting these pulse signals, the position (movement amount) of the line sensor camera (9) can be determined. can.

In detecting pinholes in the negative film fll, as described above, the negative film fi+ is fixed at a predetermined position on the mount (2) using a positioning means such as a pin system. After that, input the size of the negative film + 11 from the operation panel (51) and press the detection start button. Upon receiving this signal, the large arm (6) above the mount (2) is sent to the CPU Q3 in the Y direction. A drive command is given to the drive unit (8) to move to the front end of the negative film and stop at the front end of the negative film. The small arm (7) on the large arm (6) similarly moves in the X direction, and the drive unit (8Y is controlled by the XY position control circuit As a result, the line sensor camera (9
) is set at the right corner (or left corner) of the front end of the negative film (1).

Next, while the large arm (6) moves little by little in the Y direction, the line sensor camera (9) on the small arm (7) captures image information divided into fine pixels. When the large arm (6) reaches the trailing edge of the negative film,
The small arm (
7) in the X direction by a predetermined amount, the large arm (6) moves again in the Y direction, and by repeating this operation, the entire surface of the negative film +L+ can be scanned.

Image information for each pixel that is sequentially input from the line sensor camera (9) is processed according to the pinhole discrimination program shown in the flowchart of FIG.

Image information (step 31) sequentially input pixel by pixel from the line sensor camera is sent to the A/D converter c31.
) is converted into digital data and stored in the buffer memory G.
2 is stored. Here, the A/D conversion by the A/D converter c31) is a one of "0" and "1" with a threshold level set to an appropriate intermediate value between the white level and the black level.
It is assumed to be a bit signal. As a result.

Image information is expressed as 0 for darkened areas and 1 for transparent areas of the negative film.

Next, image information for each pixel is sequentially read out from the buffer memory 03 (step S3), and it is determined whether the content is 0 or 1 (step 34).

Here, if one image information is 0, the pixel on the film corresponding to the image information captured by the detection section is a blackened area, and therefore no processing is required.

However, if 1 image information is 1, the corresponding pixel on the film is a transparent part, and there is a possibility of a pinhole, so remember the address of the corresponding pixel (think of it as the X and Y coordinates with respect to the origin). (Step 5).

Here, just because a pixel is transparent, it does not necessarily mean that it is a pinhole; it may be a single character or a line. Therefore, eight pixels around the address (corresponding to P1 to P8 with respect to PO as shown in FIG. 3) are sequentially called out (step 6).

Depending on whether the called surrounding pixels are 0 or 1 (step 7), if all the surrounding pixels are 0, the target pixel is considered to be an isolated transparent part and the size is 60 μ information φ
Since the transparent small dot in the image cannot be anything other than a pinhole, it is determined to be a pinhole (step 8).

As a result, since a pinhole exists at the address stored in step 5, the address is stored in the pinhole address memory c37) (step 9).

Subsequently, the process returns to step 3 and the pixels are determined one after another.

Further, in step 7, if there is a pixel that is 1 among the two peripheral pixels, the counter is incremented by 1 and the peripheral pixels are checked one after another in step 11).

(Step 12), and if the counter value is smaller than the predetermined value N in a state where there is no transparent part in one peripheral pixel (Step 15).

These pixels are determined to be pinholes (step 14
). As a result, the processing from step 8 onwards was performed and pinholes were generated. Store the address in the pinhole address memory (3η).

Furthermore, as a result of counting the transparent parts of surrounding pixels one after another, if the value of the counter exceeds N, the target pixel is determined to be other than a pinhole such as a character or line (step 15).
.

That is, counting the number of pixels in which the transparent parts are connected one after another and exceeding a certain number at once means that the transparent parts have a size that is connected to a certain number or more.

This means that the target pixel can be considered to be part of a character, line, etc.

As a result, it is sufficient to return to step 3 and inspect the pixels one by one.

The above is an example of 1 discrimination method, but this method is not the only discrimination method (other methods 1, for example, can be done in advance).

There is also a method of specifying one character part manually and then painting out all the transparent parts outside the specified area.

Other methods are also possible. However, if the pinhole can be clearly distinguished from other transparent parts, there is no problem.

The discrimination method may also be realized by a - code configuration.

It may also be done by a program as in this embodiment.

The pinhole on the negative film +11 detected in this way is 1. For example, based on the address information, the pinhole is displayed together with the image on a CRT display, 1 and the operator is informed of the location of the pinhole, thereby reducing the burden of opaque work. Also, like the present invention, it has a small arm and a large arm that move in the X and Y directions,
Input the required pinhole position information into the coating device that has an Op-2 pen attached to an appropriate position on the small arm, place and fix the negative film at a predetermined position on the mount, and press the input position. The large arm and small arm may be moved based on the information, and pinholes may be automatically painted over with an opaque pen. In the latter case, the pinhole position information may be input directly to the smearing device, or may be recorded on a recording medium such as a floppy disk and input via this recording medium.

〔Effect of the invention〕

As described above, according to the pinhole detection device of the present invention, it is possible to automatically detect pinholes that appear in the blackened part of the squirrel-shaped film used in the photolithography process without manual intervention, thereby saving labor. This has the great advantage of not only being highly effective, but also eliminating the possibility of detection errors because it does not depend on the judgment of a single person.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an external view showing the basic configuration of the pinhole detection device of the present invention, and FIG. 2 is a block diagram of the processing circuit of the present invention. , FIG. 3 is a flowchart of the pinhole discrimination method of the pinhole detection device of the present invention, and FIG. 4 is a model diagram showing the pixel level relationship in the pinhole discrimination method of the pinhole layer detection device of the present invention. be. il+...Negative film (3)...Light source (6)...Large arm (7)...Small arm (8)...Large arm drive section (8)'...Small arm drive object

Claims (1)

[Scope of Claims] 1) A device for detecting pinholes generated in a squirrel-shaped film used in photolithography, which includes a pedestal for fixing the target film, and a pedestal provided below the pedestal, in which the film is passed through the pedestal. an arm mechanism movable in two orthogonal directions on the pedestal; a drive means for moving the arm mechanism; It is characterized by comprising an optical sensor that receives light through a film, a determining means that determines whether or not it is a pinhole based on image information from the optical sensor, and a position calculating means that calculates position information of the determined pinhole. Pinhole detection device. 2) The pinhole detection device according to claim 1, wherein the optical sensor is a line sensor. 3) The pinhole detection device according to claim 1, wherein the determining means performs the determination based on the size of the white spot.