JPS6337882B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inspection head used in a pattern area measuring device for panels such as offset printing plates, and more particularly to the structure of a mask that covers an illumination light source of an irradiation optical system of an inspection head.

A pattern area measuring device that measures the pattern area ratio of panels such as offset printing plates adsorbs the panel to be measured (including metal plates, flexible resin sheets, etc.) onto a table formed on the front of the main housing. The image area on the fixed panel surface is measured by moving and scanning the inspection head over the panel surface.

The inspection head has an irradiation optical system that illuminates the panel surface with irradiation light, and an optical detection device that receives reflected light from the illuminated panel surface.This optical detection device detects the reflected light from the panel surface. The intensity of the light is detected optically.

Therefore, in order to improve the detection accuracy when optically detecting the picture area ratio of the panel, it is necessary to
It is necessary to reliably irradiate (expose) the detection area on the panel surface with the illumination light from the illumination optical system so that only the reflected light from the detection area is received by the optical detection device.

In consideration of the above-mentioned points, this invention reliably illuminates the detection area on the panel surface with illumination light from the illumination optical system, and guides the reflected light from this detection area to the optical detection device, thereby improving detection accuracy. An object of the present invention is to provide an inspection head for a panel pattern area measuring device, etc., which can reliably measure the pattern area of a panel.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall perspective view showing a panel picture area measuring device using an inspection head 10 according to the invention, and reference numeral 11 indicates a main body housing of the picture area measuring device. A negative pressure source (not shown) such as a blower is housed within the main body housing 11, and a table 12 is integrally molded on the front surface thereof. The front of the table 12 is the punching plate 1
Panel 14 covered by 3 and offset printing plate etc.
A mounting surface is formed on which the material is placed. This mounting surface is inclined upward so as to gradually approach the back side of the main body housing 11, and due to this inclination, the panel 14 is placed on the punching plate 13 of the table 12.
is placed easily and smoothly. table 12
The panel 14 placed above is positioned and held by a lower positioning bar 15 and either left or right positioning pins 16.

On the other hand, a pair of guide rods 17 and 18 are provided horizontally at the upper and lower front surfaces of the main body housing 11, and the horizontal movement of the inspection head 10 is guided by the guide rods 17 and 18. The inspection head 10 is mounted so as to straddle the table 12 and is reciprocated on the table 12. The pattern area ratio of the panel surface on the table 12 is measured by this movement and scanning of the inspection head 10.

The inspection head 10 has a box-like casing 20, inside which a second
As shown in principle in the figure, an illumination optical system 21 and an optical detection device 22 are provided. Illumination optical system 21
Two fluorescent lamps 2 are installed in parallel as a linear illumination light source.
It has 3.23. As shown in FIG. 3, the fluorescent lamps 23, 23 are held near their ends by fixed holders 24, and are fixed to both bottoms of the casing 20.

The optical detection device 22 is installed above the intermediate portion between the two fluorescent lamps 23, 23, as shown in FIG. 4, and is fixed to the bottom wall of the casing 20 by a mounting fixture 25 having an L-shaped cross section. , are housed in a box-like shape of the casing 20. The optical detection device 22 includes a large number of light shielding boxes 26 arranged in a row,
A light sensor 27 such as a photodiode as a light receiver is attached to the top of this light shielding box 26.
and has. The lower part of the light-shielding box 26 is open, and a slit 28 is provided at the lower end opening. However, the fluorescent lamps 23 are installed on both sides of the opening at the lower end of the light shielding box 26.

The fluorescent lamps 23, 23 constituting the illumination optical system 21 are covered from both sides with a mask 30. mask 3
0,30 are attached to the lower part of the casing 20,
It has an arcuate or elliptical curved section 31 that covers the fluorescent lamps 23, 23 from the outside, and a straight section 32 that extends obliquely from the outer lower end of the curved section 31 toward the panel 14 or table 12 surface. The fluorescent lamp 23 is disposed at the center or focal point of the curved portion 31 and opens toward the panel 14 side. Further, the curved portion 31 is formed as a reflective surface 31A that reflects the irradiated light from the fluorescent lamp 23. Further, the linear portions 32 of both masks 30 are coated with black and are formed as non-reflective surfaces 32A that absorb the irradiated light from the fluorescent lamps 32.
This prevents adverse effects caused by reflection from the non-reflective surface 32A. The area of the non-reflective surface 32A may be within a range that can prevent the fluorescent light from directly entering the light shielding box 26 of the optical detection device 22 from the slit 28.

Further, both the linear parts 32, 32 of the mask 30 are inclined in a direction that gradually approaches the panel surface side, and terminate near the panel 14 surface, forming an elongated rectangular window part 35.
is formed. This window portion 35 extends parallel to the longitudinal direction of the fluorescent lamp 23, and the irradiation light from the fluorescent lamp 23 passes through the window portion 35 and exposes the detection area A on the panel surface to a slit.

That is, a rectangular window 35 is formed in the mask 30 at a position close to the panel surface, thereby irradiating only the detection area A on the panel surface for slit exposure. On the other hand, as shown in FIG. 5, by providing the mask 30 with an inclined straight part 32, the detection area A
The reflected light of the panel 14 from other sources is cut off, and the reflected light can be prevented from entering the optical detection device 22. If there is no straight portion 32, the fluorescent lamp 23 irradiates a point P on the panel surface as shown by a dashed line, and the detection area A is affected by the reflected light reflected at this point P. In that case, P
The point is the panel surface of an offset printing plate, etc., and the amount of reflected light varies depending on the presence or absence of a pattern, so the influence of the amount of reflected light from point P changes the illuminance of detection area A.
This may cause measurement errors. Furthermore, by making the inner surface of the straight portion 32 a non-reflective surface (anti-reflection surface) 32A, there is no reflected light as shown by the broken line on the non-reflective surface 32A, so that changes in reflection at the straight portion 32 are caused by changes in the reflection on the panel 14. The illuminance of the detection area A is not affected. Therefore, the detection area A of the panel 14 always has a constant illuminance.

Incidentally, reference numeral 37 denotes light shielding plates attached to both sides of the panel at a position passing through the calibration mark 38.

Furthermore, the upper limit of the non-reflective surface of the mask 30 is
For example, it may be point L in the figure. When a line connecting the center of the window 35 and the center O of the fluorescent lamp 23 forms an angle α from the panel surface, this point B is perpendicular to the line of this angle α, and a straight line passing through the center O is the mask 30. This is the point where it intersects with

Next, the operation of the inspection head 10 will be described.

Irradiation light from both fluorescent lamps 23, 23 of the illumination optical system 21 is irradiated onto the detection area A of the panel 14 through the rectangular window 35 of the mask 30, and that area is subjected to slit exposure. At that time, the panel 14 is
It is attracted to the top and fixed in place. Due to the slit exposure, the reflected light from the detection area A of the panel 14 passes through the slit 28 and is detected by the optical detection device 22.
The light enters each light shielding box 26 and is received by a light sensor 27 such as a photodiode as a light receiver installed at the top of each of them, and the pattern area of the panel is measured for each light shielding box 26 based on the strength of the reflected light. be done. Thus, the photo sensor 27 of each light-shielding box measures the pattern area, thereby measuring the pattern area ratio of the panel detection area A subjected to slit exposure.

Once the picture area ratio of a particular panel detection area A has been measured, the inspection head 10 is moved to measure the picture area ratio of the next panel detection area. Actually, since the area ratio of the picture (pattern) in the panel detection area A is instantaneously measured by the optical detection device 22, the detection head 10 is continuously moved and scanned.

Therefore, due to the moving scanning of the inspection head 10,
On the panel 14, the area ratio of the pattern is measured for each detection area.

Note that the straight section of the mask does not necessarily have to be a straight straight line; it is sufficient if the cross section approximates a straight line, and it may be curved as long as it is smooth.

Furthermore, the inner surface of each light-shielding box of the optical detection device may be coated with black to provide a non-reflective surface to prevent reflection.

As described above, in the detection head for a panel pattern area measuring device, etc. according to the present invention, a mask is provided so as to cover the illumination light source of the illumination optical system, and the mask extends toward the panel surface and is close to the panel. Since the window portion is formed to perform slit exposure at the position, the irradiation light can be reliably irradiated onto the detection area of the panel through the window portion, and slit exposure can be performed. Then, the reflected light from the slit-exposed detection area enters the optical detection device, and the reflected light from areas other than the panel detection area is blocked by a mask, improving the detection accuracy of the panel detection area and making the panel detection area more efficient. can be measured optically and precisely.

In addition, in a mask that has a curved part that covers the linear illumination light source and a straight part that extends from this curved part to the panel surface side, if the straight part is used as a non-reflective surface for absorbing the irradiated light, the non-reflective surface No reflected light is guided directly to the optical detection device. Therefore, disturbances such as reflected light from the straight portion are not guided to the optical detection device, and the detection accuracy of the panel detection area can be further improved.

[Brief explanation of the drawing]

FIG. 1 is an overall perspective view showing a panel pattern area measuring device using an inspection head according to the present invention, and FIG.
The figure is a principle diagram of an inspection head for a panel picture area measuring device, etc. according to the present invention, FIG. 3 is a partial view of the lower half of the inspection head, and FIG. 4 is a cross section taken along the - line in FIG. 3. 5 is a sectional view similar to FIG. 4 showing the principle of reflection of irradiated light from the illumination optical system of the inspection head. 10... Inspection head, 11... Main body housing, 12... Table, 14... Panel, 20...
... Casing, 21 ... Illumination optical system, 22 ... Optical detection device, 23 ... Fluorescent lamp, 26 ... Light shielding box, 27 ... Light sensor, 28 ... Slit,
30...Mask, 31...Curved part, 31A...Reflective surface, 32...Straight line part, 32A...Non-reflective surface, 3
5... Window section, A... Panel detection area.

Claims (1)

[Claims] 1 A panel having an irradiation optical system that irradiates a panel such as an offset printing plate placed on a table with irradiation light, and an optical detection device housed in a casing to detect reflected light from the irradiated panel. In the inspection head for a picture area measuring device, etc., the irradiation optical system has a plurality of linear illumination light sources arranged in parallel at the bottom of the casing, while the optical detection device has a plurality of linear illumination light sources arranged in parallel at the bottom of the casing, while the optical detection device has a plurality of linear illumination light sources arranged in parallel at the bottom of the casing. A mask is housed in a casing and is provided to cover each of the linear illumination light sources from the outside, and each mask has an arc-shaped or It has an elliptical curved section and a straight section that extends obliquely from one end of the curved section toward the panel surface and terminates at a position close to the panel surface, and exposes the panel surface detection area to slit exposure between adjacent straight sections. A panel in which a rectangular window portion is formed as shown in FIG. Inspection head for picture area measuring devices, etc.