JP7209329B2 - inspection equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection apparatus that irradiates an object to be inspected with electromagnetic waves such as X-rays and inspects foreign matter in a non-destructive manner.

In general, in each process from product manufacturing to packaging and shipping, foreign matter, etc., inside the product and packaging is inspected using an inspection method suitable for the product to be inspected and the type (material, size, etc.) of foreign matter that may be mixed. are inspected for contamination.

Among them, in the non-destructive inspection, for example, an object to be inspected is irradiated with electromagnetic waves such as X-rays, and the transmitted electromagnetic waves are detected. At this time, the degree of transmission of the electromagnetic wave varies depending on the presence or absence of foreign matter in the inspection object, the material of the foreign matter, and the like. Therefore, by generating a two-dimensional image in which the intensity distribution of the detected electromagnetic waves is represented by shading, etc., it is possible to inspect the internal conditions of the object to be inspected, which cannot be known from the external appearance.

Specifically, for example, an electromagnetic wave transmitted through an inspection object conveyed in a predetermined direction by a conveying means is detected by an array of detection elements arranged substantially perpendicular to the conveyance direction of the inspection object. A two-dimensional image of the object to be inspected is generated by outputting detection data for each cycle according to the conveying speed and sequentially arranging linear electromagnetic wave transmission images generated based on the detection data (Patent document 1).

In each period, the plurality of detection elements forming the detection element array detect electromagnetic waves at the same time. Data detected by each detecting element that simultaneously detects electromagnetic waves in the current period is stored in a temporary storage area and then sequentially read out by the reading means. In parallel with this reading process, electromagnetic waves in the next period are detected.

JP 2015-64336 A

When it is desired to increase the transport speed of the object to be inspected, in terms of electromagnetic wave detection, shortening the cycle in which the detection element array outputs detection data may cause problems such as darkening of the image due to the shortening of the exposure time. I can deal with it for the time being.

However, there is a limit to speeding up the detection data reading process due to the mechanism of the reading means, which limits the transport speed. That is, the larger the number of detection elements forming the detection element array, the more time it takes to read out, so the upper limit of the conveying speed is lowered. In addition, in a line sensor (one row of detection elements), reading must be performed within a very limited time for the inspection object to pass through that row, so there is very little room for increasing the conveying speed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inspection apparatus capable of increasing the upper limit of the conveying speed of an object to be inspected in non-destructive inspection using electromagnetic waves, compared to conventional inspection apparatuses.

The inspection apparatus of the present invention includes electromagnetic wave irradiation means for irradiating an object to be inspected with electromagnetic waves, transport means for transporting the object to be inspected in a predetermined transport direction, and a plurality of are arranged in two or more rows in a predetermined conveying direction, and each detecting element emits an electromagnetic wave transmitted through an object to be inspected, which is conveyed by one row of the detecting element rows for a time t. detection means for simultaneously performing detection in a longer detection cycle and outputting detection data; and inspection means for inspecting the inspection object based on the detection data read by the reading means.

By configuring the inspection apparatus in this way and providing a plurality of readout means so as not to exceed the readout capability of the readout means, a longer readout time is ensured than in the case of a single row of detection elements, thereby increasing the upper limit of the transport speed. be able to.

The detection period may be, for example, the number of detection element arrays×time t.

Detection of electromagnetic waves by each detection element may be performed during a partial period of the detection cycle.

In the two or more reading means, the total number obtained by multiplying the number of detection elements per one detection element row by the number of detection element rows along which the object to be inspected advances in the detection period is obtained by one reading means in the detection period. The number may be divided by the maximum number of detection elements from which detection data can be read. As a result, the number of reading means can be set without waste.

Sequential reading of each detection data simultaneously detected and output by each detection element may be performed, for example, after the detection data is stored in temporary storage means provided for each detection element.

1 is a functional block diagram of an inspection device 100 of the present invention; FIG. FIG. 13 is a diagram (1/3) for explaining how the detection means 130 detects an electromagnetic wave transmitted through an inspection object W and periodically outputs detection data; FIG. 11 is a diagram (2/3) for explaining how the detection means 130 detects an electromagnetic wave transmitted through an inspection object W and periodically outputs detection data; FIG. 3 is a diagram (3/3) for explaining how the detecting means 130 detects an electromagnetic wave transmitted through an inspection object W and periodically outputs detection data; 3 is a diagram showing a configuration example from a detection means 130 to a reading means 140; FIG.

<First Embodiment>
FIG. 1 shows a functional block diagram of the inspection apparatus 100. As shown in FIG. The inspection apparatus 100 includes electromagnetic wave irradiation means 110 , transport means 120 , detection means 130 , reading means 140 and inspection means 150 .

The electromagnetic wave irradiating means 110 irradiates the inspection object W conveyed by the conveying means 120 with electromagnetic waves such as X-rays, ultraviolet rays, visible rays, and infrared rays.

The conveying means 120 conveys the inspection object W placed on the conveying surface forming the XY plane in the three-dimensional orthogonal coordinate system in the Y-axis direction at a predetermined speed. It is desirable that the conveying means 120 have high electromagnetic wave permeability so that the electromagnetic waves transmitted through the inspection object W reach the detection means 130 with as little attenuation as possible.

The detecting means 130 is configured by arranging two or more rows of detecting elements in the Y-axis direction, each of which is composed of a plurality of detecting elements arranged substantially in the X-axis direction. Each detecting element of all the detecting element arrays simultaneously detects the electromagnetic waves transmitted through the inspection object W conveyed by one of the detecting element arrays at a time t at an arbitrary detection cycle longer than the time t, and detects the detection data. to output

With reference to FIGS. 2 to 4, detection means 130, which is composed of eight detection element rows arranged substantially in the X-axis direction and arranged in four rows in the Y-axis direction, detects one of the detection element rows. A description will be given of how the electromagnetic wave transmitted through the inspection object W conveyed in the Y-axis direction for a row at time t is detected and the detected data is periodically output. Note that the number of detection element arrays and the number of detection elements constituting the detection element arrays are arbitrary, and even if the numbers are different, the same effect can be obtained by setting the output period according to the numbers. can.

FIGS. 2 to 4 illustrate the case where the inspection object W has a width corresponding to eight detection element rows. Hereinafter, the four detection element arrays are referred to as the first detection element array, the second detection element array, . The eight areas are called a first area, a second area, . . . from the top in the transport direction.

Assuming that the time immediately before the inspection object W approaches the first row of detection elements is 0, the first region is on the first row of detection elements (4th and 5th detection elements) at time t. , and at time 2t, the first region is on the second detector element row (the 4th and 5th detector elements), and the second region is on the first detector element row (the 4th and 5th detector elements). detection element). After the time 3t, each area of the inspection object W sequentially passes over each row of the detection element arrays, and all areas pass over all the detection element arrays at the time 12t.

The electromagnetic wave transmitted through the inspection object W is simultaneously detected by 32 detection elements in four detection element arrays, and detection data corresponding to each detection element is output at a cycle of 4t. 4t corresponds to the time required for each region of the inspection object W to pass through the four detection element arrays. In this way, by setting the time required for the inspection object W to move in the width of the detection means 130 in the conveying direction to be a predetermined cycle for outputting the detection data, for example, linear detection based on the detection data obtained in each cycle can be performed. A two-dimensional image of the inspection object W can be obtained by simply arranging the images of .

In each detection period, the period (exposure period) during which each detection element detects electromagnetic waves may be set arbitrarily. That is, detection may be performed over the entire period of the detection cycle, or may be performed only during a part of the period.

In the examples of FIGS. 2 to 4, each detection element detects electromagnetic waves from time 0 to time t in each period, and stops detection from time t to time 4t. While detection is stopped, the charge generated during detection is held, and detection data based on the held charge is output at time 4t. Specifically, in the first cycle, detection data corresponding to electromagnetic waves detected by each detecting element between time 0 and time t is output at time 4t. At this time, detection data of the electromagnetic wave transmitted through the first region of the inspection object W is obtained as detection data detected by the fourth and fifth detection elements of the first row of detection elements. In the second cycle, detection data corresponding to electromagnetic waves detected by each detection element between time 4t and time 5t are output at time 8t. At this time, the detection data of the electromagnetic wave transmitted through each of the second to fifth regions of the inspection object W is detected by the 4th and 5th detection element rows of the 4th to 1st rows. It is obtained as detection data detected by the element. In the third cycle, detection data corresponding to electromagnetic waves detected by each detection element between time 8t and time 9t are output at time 12t. At this time, the detection data of the electromagnetic wave transmitted through each of the sixth to eighth regions of the inspection object W is detected by the fourth and fifth detection element rows of the fourth to second rows. It is obtained as detection data detected by the element.

The period during which electromagnetic waves are detected is not limited to the examples in FIGS. 2 to 4. For example, it may be a different period t such as time 3t to time 4t in each cycle, or a period longer than t such as time t to time 3t. I don't mind.

Each detection element constituting the detection means 130 may be of any type as long as it detects the irradiated electromagnetic wave and generates an output corresponding to the detected intensity. Taking the case where the electromagnetic waves irradiated to the inspection object W are X-rays as an example, the X-rays are first converted into visible light by a scintillator, and then received by a photodiode to generate an output by an indirect conversion type detection element. Alternatively, a direct conversion type detection element using a semiconductor such as CdTe that converts X-rays directly into an electric signal to generate an output can be applied.

When the detection data is simply output as a voltage intensity, for example, a photodiode is adopted as each detection element. If the detection period is, for example, 4t, while the electromagnetic wave is detected in the detection period (for example, from time 0 At time t), the charge generated by the photoelectric effect is accumulated in the charge amplifier, the accumulated charge amount is converted into a voltage value, and output as detection data at time 4t.

Further, when the detection data is output as photon count data for each energy band, for example, if a CdTe element is adopted as each detection element, if the detection period is, for example, 4t, while the electromagnetic wave is detected in the detection period For each of a plurality of photons incident on the detection element (for example, from time 0 to time t), the amount of charge generated by the photoelectric effect is converted into an energy value and counted as the number of photons in the corresponding energy band. The number of photons for each energy band thus obtained is output as detection data at time 4t.

The detection data for each detection element output from the detection means 130 may be stored, for example, in the temporary storage means 160, which is an arbitrary storage means. By storing the detection data in the temporary storage unit 160 in this way, the detection processing of the next period in the detection unit 130 can be quickly started in parallel with the reading processing by the reading unit 140 .

The two or more reading means 140 share and read the detection data of all the detection elements constituting the detection means 130 for each detection cycle. The number of reading means 140 is arbitrary. If the number of reading means 140 divided by the maximum number of detection elements from which detection data can be read is provided, the number of reading means can be set without waste.

In the example shown in FIGS. 2 to 4, the inspection object W advances through four detection element arrays during a period of 4t, and each detection element array consists of eight detection elements. There are 32 detection elements from which detection data are read.

At this time, if the maximum number of detection elements that can read detection data during 4t is 31 or less, one readout means 140 cannot read all the detection data. Therefore, two reading means 140 are provided when the number of detection data that can be read by the reading means 140 during 4t is 16 or more and 31 or less, and when it is 11 or more and 15 or less, reading For example, three reading means 140 may be provided, and the number of reading means to be provided should be increased as the reading ability of the reading means is low.

FIG. 5 is a diagram showing a configuration example from the detecting means 130 to the reading means 140 when the maximum number of detection elements from which detection data can be read by the reading means 140 during 4t is 16 or more and 31 or less. be.

The detection means 130 includes four detection element arrays S1 to S4, each of which includes eight detection elements E1 to E8. Each detection element is individually connected to the reading means 140 via the wiring L interspersed with the temporary storage means 160 .

Two readout means 140 are provided. One readout means 140a is connected to a total of 16 detection elements of the detection element arrays S1 and S2, and the other readout means 140b is connected to a total of 16 detection element arrays S3 and S4. Sixteen sensing elements are connected.

Specific processing in the configuration example of FIG. 5 will be described. First, as shown in FIG. 2, the detecting means 130 detects electromagnetic waves from time 0 to t, and the detected data is output at time 4t and stored in the temporary storage means 160 . Subsequently, as shown in FIG. 3, among the detection data of the first period stored in the temporary storage means 160, the detection data from the detection element arrays S1 and S2 are read by the reading means 140a, and the detection element arrays S3 and S4 are read out. are read out by 140b, both between times 4t and 8t. Further, while the readout process is being performed by the readout means 140, the detection means 130 detects the electromagnetic wave in the second cycle between time 4t and time 5t, and the detected data is output at time 8t and temporarily stored. stored in means 160; Subsequently, as shown in FIG. 4, among the detection data of the second cycle stored in the temporary storage means 160, the detection data from the detection element arrays S1 and S2 are read by the reading means 140a, and the detection element arrays S3 and The sensed data from S4 are read out by 140b, both between times 8t and 12t. Further, while the readout process is being performed by the readout means 140, the detection means 130 detects the electromagnetic wave in the third period between time 8t and time 9t, and the detected data is output at time 12t and temporarily stored. stored in means 160; Then, among the detection data of the third period stored in the temporary storage means 160, the detection data from the detection element arrays S1 and S2 are read by the reading means 140a, and the detection data from the detection element arrays S3 and S4 are read by 140b. are both read out between times 12t and 16t.

FIG. 5 illustrates a configuration in which the reading means 140a and the reading means 140b share the same number of pieces of detection data. I do not care. Also, three or more reading means 140 may be provided to share the load. Also, it is arbitrary to let each reading means 140 share which detecting element.

Since t is the time required for the inspection object W to travel the width of one row of detection elements, the absolute value of the required time changes according to the transport speed of the inspection object W. FIG. That is, t is a short required time when the conveying speed is fast, and a long required time when the conveying speed is slow.

Therefore, for example, even if the reading means 140 can read 16 pieces of detection data during 4t at a certain transport speed, the absolute value of the time indicated by 4t is halved when the transport speed is doubled. , the number of detection data that can be read is also halved to eight.

However, by providing an appropriate number of reading means in consideration of such circumstances, all detection data to be read can be read even if the transport speed is increased.

The inspection means 150 inspects the object W to be inspected based on the detection data corresponding to the respective detection elements read by the reading means 140 in each cycle as described above. The inspection to be performed includes a foreign matter inspection, an inspection object passage inspection, a visual inspection, and the like. For example, in the case of foreign matter inspection, detection data is used to automatically determine the presence or absence of foreign matter in the inspection object. In the case of visual inspection, a two-dimensional image is generated based on the detection data and displayed on display means 151 such as various displays so that the inspection object can be visually inspected.

As described above, according to the inspection apparatus 100 of the present invention in which two or more detector element arrays are provided and a plurality of readout means are provided so as not to exceed the readout capability of the readout means, the readout time is can be ensured, and the upper limit of the conveying speed can be increased.

In addition, the present invention is not limited to the above embodiments. Each embodiment is an example, and the present invention can be any one that has substantially the same configuration as the technical idea described in the claims of the present invention and produces similar effects. included in the technical scope of That is, modifications can be made as appropriate within the scope of the technical ideas expressed in the present invention, and forms with such modifications and improvements are also included in the technical scope of the present invention.

DESCRIPTION OF SYMBOLS 100... Inspection apparatus 110... Electromagnetic wave irradiation means 120... Conveying means 130... Detection means 140, 140a, 140b... Reading means 150... Inspection means 151... Display means 160... Temporary storage means E1, E2, E3, E4, E5, E6, E7, E8... Detection element L... Wiring S1, S2, S3, S4... Detection element array t... Time (time)
W ... inspection object

Claims (4)

an electromagnetic wave irradiating means for irradiating an object to be inspected with X-rays;
a conveying means for conveying the inspection object in a predetermined conveying direction;
Detecting element arrays composed of a plurality of detecting elements arranged in a direction substantially orthogonal to the predetermined conveying direction are arranged in four lines in the predetermined conveying direction, and one line of the detecting element arrays is conveyed in time t. detection means for simultaneously detecting the X-rays transmitted through the inspection object by the respective detection elements at a detection cycle longer than time t and outputting detection data;
2 reading means for sharing and reading the detection data of all the detection elements output from the detection means for each detection cycle;
inspection means for inspecting the object to be inspected based on the detection data read by the second reading means;
with
The detection data of the detection elements included in the two rows of detection elements on the upstream side in the predetermined transport direction are read by one of the reading means, and the detection data on the two rows on the downstream side in the predetermined transport direction are read. The detection data of the detection elements included in the element array are read by the other reading means.
inspection equipment. 2. The inspection apparatus according to claim 1, wherein the detection cycle is the number of rows of the detection element rows×time t. 3. The inspection apparatus according to claim 1, wherein the detection of the X-rays by the detection element is performed during a partial period of the detection cycle. Temporary storage means for storing detection data output from the detection element is provided for each detection element,
4. The inspection apparatus according to claim 1 , wherein said reading means reads the detection data from said temporary storage means.

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