JPH0196685A - Hologram inspecting device - Google Patents

Abstract

PURPOSE:To inspect a hologram quantitatively and automatically by deciding whether or not a hologram is normal according to the intensity of light of a hologram playback image. CONSTITUTION:An original film 5 in process of manufacture is irradiate with light from a light source required for hologram image reproduction and light from the hologram image which is obtained as a result is detected to decide the level of the detection output. Namely, when the hologram on the surface of the original film 5 maintains specific quality, a hologram image having specific brightness is reproduced by the irradiation with the light from the light source 11. For the purpose, the level of light of the hologram image which is reproduced is detected to grasp the quantity of the hologram, which is thus formed. Consequently, whether or not the specific quality is maintained is monitored quantitatively in real time.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an inspection device for a hologram recording body, and in particular,
The present invention relates to a hologram inspection device suitable for automatically determining the quality of holograms during the manufacturing process of hologram recording bodies.

[Conventional technology]

In recent years, equipment has been developed that continuously manufactures holograms using a special embossing process on plastic films, making it possible to mass-produce holograms.

By the way, this device is called a rainbow hologram manufacturing device, and uses an embossing mold heated to a predetermined temperature to create fine embossing on the resin layer provided on the surface of the original film. The holograms are formed by moving the holograms one after another to different locations, but this requires preheating the mold before starting production.

However, in this rainbow hologram manufacturing equipment, the above-mentioned residual heat cannot be used solely as a warming-up for the equipment, and for this purpose, it is necessary to actually perform embossing on the original film. do.

FIG. 6 shows an example of such a rainbow hologram manufacturing apparatus.

In this figure, 1 is the supply section, 2 is the embossing section, and 3
4 is the drying section, 4 is the winding section, 5 is the original film, and 2A
2B is a plate cylinder, and 2B is an impression cylinder.

The raw film 5 is a thin polyethylene film coated with ultraviolet or electron beam curable resin on one side, and is prepared as a roll in the supply section 1, and is wound up on the winding section 4. As a result, embossing is performed continuously through the embossing section 2 and the drying section 3, and a large number of holograms are sequentially formed in the longitudinal direction of the film to be obtained in the winding section 4. become.

The plate cylinder 2A of the embossing section 2 is equipped with a mold having fine irregularities for forming a hologram, and is rotated by sandwiching the original film 5 together with an impression cylinder 2B having a heating means such as an electric heater. , this raw film 5
The resin layer on the surface is embossed to form a rainbow hologram one after another.

The drying section 3 includes an ultraviolet ray or electron beam irradiation means therein, and has the function of irradiating the resin layer of the raw film 5 with ultraviolet rays or electron beams and curing the resin layer so that the embossing on the surface remains as it is. do.

Therefore, in this device, the plate cylinder 2A having the mold is heated to a predetermined temperature by heat conduction from the impression cylinder 2B. 1 to the winding section 4, that is,
Warming-up cannot be performed unless the equipment is operated under the same conditions as when manufacturing holograms.

On the other hand, until the warming-up is completed in this way, the temperature of the plate cylinder 2A does not reach the predetermined value.
In the meantime, a complete hologram is not formed on the original film 5 being wound up on the winding section 4. That is, at first, no hologram was formed at all, but as the temperature of the plate [42A] rose due to heat conduction from the impression cylinder 2B, a hologram was gradually formed, albeit incompletely. Eventually, a complete hologram can be seen.

Therefore, in such an apparatus, when the apparatus starts operating for hologram production, the first part of the original film 5 wound up on the winding unit 4 is discarded as a defective product, and a complete hologram is produced. Once we were able to obtain this, full-scale production operations began again. Note that the time required for preheating at this time was rarely several tens of minutes.Also, even after operation begins, the hologram quality changes depending on conditions such as the condition of the original film and the pressure and heating temperature. Due to this, operators were constantly monitoring the situation.

[Problem that the invention seeks to solve]

In the above conventional technology, no particular consideration is given to monitoring the hologram formation state during the hologram manufacturing process, and the operator monitors the state of the raw film flowing through the manufacturing process and takes necessary measures. It's just a matter of being able to do it.

Therefore, in the conventional technology, proper monitoring by the operator is required at all times, and a decline in chain production is unavoidable.
It is difficult to keep the consumption of raw film, which is used only for warming up, to the minimum ratio, and furthermore, the quality of holograms changes due to changes in manufacturing conditions after hologram production begins. It was also difficult to respond appropriately to this problem, resulting in lower quality and yield, and even higher costs.

An object of the present invention is to establish a method that can quantitatively determine the state of a hologram, and thereby to provide a hologram inspection device that enables real-time monitoring of holograms in a hologram production line. .

[Means for solving problems]

The above purpose is to irradiate the original film in the manufacturing process with the light source light necessary for reproducing the hologram image, detect the light from the hologram image that will be obtained by this, and judge the level of this detection output. This is achieved in this way.

[Effect]

If a hologram is formed on the surface of the original film while maintaining a predetermined quality, a hologram image with a predetermined brightness should be reproduced by irradiating the hologram with the light source.

Therefore, if we detect the level of light from the hologram image that will be reproduced at this time, it will indicate the quality of the hologram, and it will be possible to determine whether the hologram has been formed and whether it maintains the specified quality. This monitoring can be done quantitatively in real time.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A hologram inspection apparatus according to the present invention will be explained in detail below using illustrated embodiments.

FIG. 2 shows an embodiment of the present invention, in which 7 is a detection head, 8 is a rotary encoder, 9 is a hologram inspection device main body, 1
0 is a reflecting plate, and the rest is the same as the conventional example shown in FIG.

The detection head 7 is provided at a predetermined position between the drying section 3 and the winding section 4 so as to face the reflecting plate 10 with the original film 5 in between, and is arranged as shown in FIG. It is composed of a light source device 11, a main light detector 12, and an auxiliary light detector 13. First, the light source device 11 consists of a light source such as a halogen bulb and a suitable reflecting mirror combined with the light source. A light source is provided in a predetermined range a through which the center line La in the width direction of the surface of the raw film 5 on which the hologram is to be formed passes, from a direction inclined at 45 degrees to the direction of movement of the raw film 5. It functions to irradiate light and give a predetermined illuminance to this predetermined range a, and therefore, the irradiation optical axis is lla.

Next, the main photodetector 12 is formed from a photodiode serving as a photosensor, a hood, a suitable condensing optical system, etc., and passes through the center of a range a set on the center line La of the original film 5. Along the perpendicular line, it serves to receive the reflected light appearing by the hologram reconstructed image from the range a and detect it as an electric signal, and therefore, its detection light receiving axis is 12a. Note that the detection field of view at this time is approximately 10 mm in diameter on range a.
It is designed to become a crane.

Also, like the main photodetector 12, the auxiliary photodetector 13 is made of a photodiode and a condensing optical system such as a hood. range a across the direction and perpendicular to the center line La
It is included in a plane defined as a plane B perpendicular to a transverse line Lb passing through the center of , it functions to detect only the light scattered on the surface of the original film 5, not the light reflected by the hologram reproduced image.

Note that the plane A is defined as a plane perpendicular to the center line La, and therefore the optical axis 11a of the light source 11 is also aligned with the main photodetector 12.
The optical axis 12a of the light source 11 is also included in this plane A, and the path 11b of specularly reflected light from the light source 11 in the range a is also included in this plane A.

The rotary encoder 8 is attached to the rotating shaft of the plate cylinder 20, and thereby functions to detect the rotation of the plate cylinder 8 and, in turn, the movement of the original film 5.

As shown in FIG. 3, the inspection device main body 9 includes a microcomputer consisting of a CPU 17, a data memory 18, a program memory 19, a CPU bus 20, etc. 21 is an input switch, 22 is a rotary Encoder interface, 23 is A/D (
24 is a variable gain amplifier, 25 is an S/H (sample and hold circuit), 26 is a buffer amplifier, and 27 is a display device.

Next, the operation of this embodiment will be explained.

For hologram production, when this system starts operating and the original film 5 is fed out from the supply section 1 and sent to the winding section 4 via the embossing section 2 and the drying section 3, the original film is A pulse signal e is generated from the rotary encoder 8 in accordance with the movement of the film 5, and is input to the detection circuit 9.

The signal e from the rotary encoder 8 is processed by the interface 22, which supplies the signal i to the CPU 17. As a result, the CPU 17 calculates the position of the pattern in the flow of the original film 5 by interrupt processing. Then, the detection signal S from the main photodetector 12 is stored in the corresponding address on the data memory 18. For this reason, the phase relationship between the address of the data memory 18, the signal e1 from the rotary encoder 8, and the pattern on the original film 5 is aligned by initial setting, and therefore the detection signal S
and the coordinates in the flow direction of the original film 5 correspond to one to one.

The detection signal S is sent to the CPU 17 via the following path. That is, the signal S entering the main body is first input to the S/H 25 via the buffer amplifier 26, and
Here, it is sampled and held in accordance with the timing of the pulse signal e from the rotary encoder 8. The optimal range of the held signal is selected by the variable gain amplifier 24, digitized by the A/D 23, and then sent to the CP
The CPU 17 reads it from the U bus 20.

Incidentally, the brightness of an image created by a hologram (picture) varies greatly depending on its content, and even good products have a wide range.

For this reason, if the gain at the time of reading is fixed, in the case of a dark hologram, even though it is a good product with sufficient brightness for practical use, the resolution of the A/D conversion will be exceeded and detection will not be possible.

Therefore, in the above embodiment, the S/H 24 by the CPU 17
The detection signal from the sensor is read by performing A/D conversion twice. That is, first, the gain of the variable gain amplifier 24 is maximized, the first A/D conversion and data acquisition in the CPU are performed, and the optimum range is determined by this, and then the gain range of the variable gain amplifier 24 is set to a predetermined value. value and read the signal input value again.

At this time, the gain setting of the variable gain amplifier 24 is set in steps of 2fi times for each range, and the data taken in by the CPU 17 is normalized by simply level-shifting it in accordance with the gain when reading the A/D conversion data. be able to do so.

This problem can also be solved by making the input amplifier a logarithmic compression type or by increasing the resolution performance of the A/D converter, but in this example, due to the simplicity of adjustment, etc. , which uses the variable gain amplifier method described above.

The input signals thus standardized and stored in the data memory 18 are averaged and used to determine whether they are good or bad with respect to a reference value. The average value at this time is calculated from all data for the circumference of the plate cylinder, but in this embodiment, in order to display in real time, each time new data is input, old data is subtracted and the average value is calculated. This is the so-called moving average method.

Now, the pass/fail judgment is performed as follows.

First, a reference value necessary for determination is input in advance from the input switch 21, and is read by the CPU 17.

Therefore, the CPU 17 uses the pulse signal e from the rotary encoder 8 to calculate the average value of the normalized detection signal and the preset value each time the plate cylinder 2A makes one revolution and reaches a predetermined angular position. When the level is compared with a certain reference value, and the average value is 1 and the reference value is Ll, L, ≧L, -ε ε: Depending on whether the deviation set value is satisfied, the current winding section 4 The quality of the pattern on the original film 5 that is being wound is judged,
l, , < l, , -8, and if it is defective, a warning will be output with a buzzer, etc., although it is not shown in Fig. 3. Further, the calculated average value and the like are displayed on the display device 27.

Therefore, the operator does not need to constantly monitor the hologram on the film during operation (he can easily know the occurrence of a defect using a buzzer, etc.). You can know the condition of the pattern.

By the way, the light incident on the main photodetector 12 is not only due to the hologram image reproduced from the pattern formed on the surface of the original film 5 (but also due to the incident light simply scattered on the surface of the original film 5). Light is also included, and the level of the incident light due to this scattered light changes depending on the surface condition of the original film 5, regardless of the quality of the pattern formed thereon.

On the other hand, the hologram film to be manufactured in this manner may have a normal printed pattern, such as a silk-screened pattern, independent of the hologram pattern on the hologram forming surface, and in such cases, The intensity of scattered light on the surface of the hologram is greatly influenced by the printed pattern, and there is a risk of errors occurring in the quality determination based on the brightness of the hologram image.

Therefore, in this embodiment, although not shown in FIG. 3, the signal from the auxiliary light detector 13 is also taken into the CPU 17, and the signal output from this detector 13 is greater than a certain value. The output of the main photodetector 12 at this time was not used for calculating the average value, and only the light from the hologram reconstructed image was mainly used for calculating the average value.

Figure 5 shows the relationship between the signals from each detector and the pattern.
The signal processing method in this embodiment will now be explained.

As the original film 5 moves, the signal waveform from the detector 12 that detects the light from the hologram image becomes a waveform 44 in FIG. 5(a). As described above, the signal at this time shows a change including not only the light from the hologram reconstructed image but also the scattered light from the front surface printing part. On the other hand, the signal from the auxiliary light detector 13, which is installed to detect only the scattered light from the surface printing section, has a waveform as shown at 45 in the same figure, depending on the brightness of the pattern printed by silk printing or the like. becomes.

That is, as shown in FIG. 5(d), the original film 5
In the part 47 where the surface is printed, the output is larger than in other parts, so as shown in FIG.
When the output 45 of the main photodetector 12 exceeds this level 48, the influence of the silk-printed portion can be reduced by processing such that the output of the main photodetector 12 is not used. In this embodiment, when the output of the auxiliary photodetector 13 exceeds the slice level, the current moving average value is stored in the data memory 1 as new data.
8, so that the signal processing described above can be equivalently obtained. Therefore, the waveform at this time is the fifth waveform.
As shown at 49 in Figure (C), the calculation of the moving average can be simplified.

Next, since the calculated average value is a value proportional to the average value of the brightness of the hologram, we will describe the method used to display the hologram quality and determine whether it is a good product or a defective product.

FIG. 4 is an external view of the display panel and operation panel in this embodiment.

The average value calculated from the output of the main photodetector 12 sampled and captured by the pulse signal e of the rotary encoder 8 is immediately displayed on the wasegment LED display section 29 and the bar L.
It is displayed on the ED display section 30.

The display values range from 0.0 to 9.9, and are converted and displayed so that the maximum expected brightness of the hologram is 9.9.

By the way, as is clear from FIG. 4, in this embodiment, two types of operation modes are provided in order to match with the hologram manufacturing work. That is, the fourth
In the figure, panels 31 and 32 are operation input and display units in each mode.

One of the operating modes is a start-up mode, which the panel 31 corresponds to.

Select this start-up mode using the mode selection button 33,
At the start of hologram production, if the hologram reaches the brightness set by the brightness target setting unit 34, the arrival display 35 lights up and the operator is notified by a buzzer or the like.

゛By the way, how bright a hologram can be reproduced in the end, and where to consider a good product at this time, can be determined by the operator based on past brightness data of each item or the pattern of the plate. Therefore, the operator can easily set the target, and the inspection device determines whether the target has been reached after setting the target.As a result, according to this embodiment, the hologram manufacturing machine The operator's monitoring work at start-up is performed on behalf of the operator, and it is possible to know with certainty that the point at which non-defective products can be manufactured has been reached.

The operation of this start-up mode will be explained in more detail.

Decimal 2 set by the operator using the switch in the setting section 34
The numerical value of the digit is an expression corresponding to the brightness display 29. This numerical value is converted into the same expression format as the average value data within the CPUIT, and compared with the moving average value described above.

Here, if the moving average value reaches or exceeds the target set value, the arrival display section 35 is lit and a buzzer sounds to notify the operator.

The other operating mode is a brightness reduction detection mode using the panel 32. In other words, this brightness detection mode is
This function is selected by the mode selection button 36 to notify that a hologram that has already reached the non-defective brightness has fallen below the non-defective limit.

Now, when the operator actually visually inspects the hologram and determines that it is a good product, he presses the standard value memorization button 37, and the currently displayed moving average value is stored in the CPUI 7 as the standard value L3. .

Further, when the user selects the percentage below the reference value to be considered as non-defective by using the tolerance buttons 39 to 43, the CPU calculates the corresponding tolerance value ε from the reference value. Note that holograms are usually bright (not too bright, so in this embodiment, only the lower limit value is determined).

Thereafter, each time a new average value is calculated by taking in the signal from the main photodetector 12, it is compared with the reference value L3, and when this value is less than the allowable value ε, the indicator 38 indicates that a defect has occurred. A warning is given by a buzzer or the like.

Therefore, according to this embodiment, since determination is made every time a signal is received from the main photodetector 12, alarm processing can be achieved in real time with less response delay.

Returning to FIG. 2, in this embodiment, the detection head 7 is installed so that it can be manually moved horizontally in the width direction of the original film 5, so that its position can be changed according to the condition of the pattern. It's Nishide.

Further, the detection head 7 is rotatable by 90 degrees, and the direction of the head can be determined according to the optical directionality of the image. This is because, as one of the image re-main conditions of the hologram, the direction of the light source must be aligned with the vertical direction of the pattern, and there are two types of vertical direction: parallel to the flow of the original fabric and horizontal. , in order to be able to deal with both of these. Of course, if the direction of the light source light, which is a condition for reproducing the hologram image, is at another angle, it is sufficient to rotate it accordingly.

Further, in FIG. 2, a reflecting plate 10 is provided behind the original film 5, but this is to prevent disturbance and improve detection efficiency.

Note that if an operator or the like does not enter the back surface of the detection head 7 on the original side, the reflector may not be provided and the back surface may be left without a background.

Further, in place of the reflective plate, a uniformly colored plate such as a black plate or a white plate may be provided.

Furthermore, in the above embodiment, as explained in FIG. 1, the incident optical axis of the main photodetector 12 is held perpendicular to the surface of the original film 5, but the angle at this time is not necessarily exact. Instead, it may be installed at an angle from the vertical direction within a range where light from the hologram reconstructed image can be detected.

Similarly, it goes without saying that the optical axis of the auxiliary photodetector 13 is not limited to 60 degrees.

Furthermore, it is also possible to inspect the entire surface by arranging the detection heads in the width direction.

By the way, in the above embodiment, the present invention is incorporated into a hologram manufacturing apparatus using the original film 5, and quality determination is performed online and in real time, but the present invention is not limited to this, and can be implemented. For example, it may be carried out off-line, or instead of a system in which a plurality of holograms are formed one after another on an original film, one
It may be applied to the case where one or several holograms are created in the form of sheets.

〔Effect of the invention〕

According to the present invention, since the quality of the hologram is determined based on the intensity of the light generated by the hologram reconstructed image, the hologram can be inspected quantitatively and automatically, and a reliable quality determination can always be obtained. , it is possible to sufficiently improve the quality and the yield of the raw film, and it can greatly contribute to cost reduction.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing an embodiment of a detection head in a hologram inspection apparatus according to the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a block diagram showing an embodiment of a detection circuit. Figure, Figure 4 →-←. 1-...--supply section, 2---embossing section, 2
A・---- plate cylinder, 2B-・---- single impression cylinder, 3・-・
・-Drying section, 4-- Winding section, 5-- Original film, 7-- Detection head, 8-- Rotary encoder, 9-- Detection circuit, 10 ---Reflector, 11---1--Light source device, 12-----
...Main photodetector, 13-...Auxiliary photodetector. tsl cause 11: Yumyo device 2nd cause 4/dispatched observation p 3rd cause IU Figure 4

Claims (9)

[Claims] (1) In a hologram inspection device that sequentially and automatically inspects multiple holograms, a light source means for irradiating the hologram recording medium to be inspected with the light necessary for hologram reproduction, and a light source from the light source means are provided. What is claimed is: 1. A hologram inspection device comprising: a light detection means for detecting light from a hologram reconstructed image appearing as a result of irradiation of the hologram; (2) In claim 1, the irradiation optical path from the light source means and the incident optical path by the light detection means are:
A hologram inspection apparatus characterized in that both of the hologram inspection apparatuses are configured to include a path of light source light necessary for hologram reproduction and to be included in a plane perpendicular to the hologram recording surface of the hologram recording body. (3) The hologram inspection apparatus according to claim 1, wherein the level of the detection output is provided as an average value of light from a predetermined range of the hologram reconstructed image. (4) The hologram inspection apparatus according to claim 3, wherein the average value of the light is given by expanding the light detection area of the light detection means. (5) Claim 3 is characterized in that the average value of the light is provided by capturing temporally continuous signals as the hologram recording body moves. Hologram inspection equipment. (6) In claim 1, a reflectance measuring means for measuring the light reflectance on the hologram recording surface of the hologram recording body is provided, and the correction process for the above judgment is performed based on the measurement result of the reflectance measuring means. A hologram inspection device characterized in that it is configured to perform hologram inspection. (7) In claim 6, the reflectance measuring means does not detect a hologram reproduced image on the hologram recording surface by the irradiation light from the light source means, but is a light detection means that detects scattered light. A hologram inspection device comprising: (8) Claim 1 is characterized in that the level of the detection output for the above-mentioned quality determination is configured to be set based on the detection result from a hologram recording body that has been previously determined to be good. A hologram inspection device. (9) In claim 1, the quality determination includes a predetermined tolerance range for the level of the detection output for the quality determination, and the tolerance range is configured to be arbitrarily set. A hologram inspection device characterized by: