RU2656872C1 - Microfocus device of x-ray control - Google Patents

Abstract

FIELD: defectoscopy.

SUBSTANCE: invention relates to non-destructive testing and analysis facilities for a wide range of products, such as printed circuit boards, assemblies, electronic components, microassemblies and modules, etc. Device includes a structure mounted and secured within a framework consisting of rigidly connected guides, and comprises a support frame under which an X-ray tube is fixed and centrosymmetrically relative to said frame, and a detection unit optically coupled to said tube. Between these tubes and the block, a coordinate table with a pallet placed on it is placed on the support frame for the placement of the monitoring object and designed to move along the coordinate axes X, Y, and Z. Axis of the working X-ray beam of the tube is normal to the plane of the support frame. Detection unit is located above the support frame and is placed on an arcuate beam with the possibility of moving along it to the desired angle of the solution of the working beam of the X-ray radiation of the tube. Arc-shaped beam is connected to the upper frame guide by means of a fastening means fixedly mounted opposite the X-ray tube and ensuring rotation of the beam about the axis of the working X-ray beam. Beam has a working and non-working area, where the working section is designed to move the detection unit.

EFFECT: technical result consists in expanding the arsenal of technical means of microfocus X-ray devices with high operational reliability, as well as reducing the weight and dimensions of the device without deteriorating its technical characteristics.

7 cl, 4 dwg

Description

The technical solution relates to tools for the analysis of materials using x-ray radiation and is intended for x-ray monitoring of objects in real time, requiring high spatial resolution. The solution can be used to obtain sets of projection data of the object under study, for example, for non-destructive testing and analysis of a wide range of products, such as printed circuit boards, components, electronic components, microassemblies and modules, etc.

Traditionally, the microfocus x-ray control device is constructed according to the scheme of the microfocus x-ray source - the object of study - the X-ray receiver and contains optically coupled x-ray tube and a high-resolution flat-panel detector as the main components. Such a device can be placed in an X-ray protective housing, which allows it to be installed directly in production rooms without additional safety requirements. When conducting research, the object of analysis is placed on a coordinate table located on the path of the x-ray beam from the x-ray source to the detector. In addition to these components, the structure of the device includes, as a rule, a movement system with various manipulators, providing interconnected movement of the components of the device relative to each other. This system provides, for example, moving the table in the horizontal plane X Y, tilting the detector and moving it along the guides to ensure the maximum possible angular and circular view, as well as moving the table along the vertical Z axis.

The prior art device for analyzing an object using x-ray radiation (US patent No. 6687328, publ. 03.02.2004). An X-ray tube, a detector, a translational system (positioning) of the tube and detector in the X and Z directions are placed in the X-ray protective case of the device, the table is a platform with a pallet on which the object of study (sample) is located. In the plane of the platform with the pallet, the external and internal frames are fixed with corresponding drives to enable comprehensive analysis of the sample placed on the pallet. Frames with a fixed table - platform work on the principle of a gimbal. The translational movement system is attached to the inside of the housing and consists of several guides. An X-ray tube is attached to one of these guides located above the object table, and a detector is attached to the other, located under the object table. Both the tube and the detector are arranged to move along the respective guides. Image acquisition is performed by exposure to x-ray radiation on the studied region of the sample in its several spatial positions. At the same time, the tube and detector can only move translationally, and the platform with the sample placed on it, thanks to the hinged mounting in the frames, can rotate in at least one plane, or simultaneously in several planes (maximum - in three).

There is also a device for x-ray control of electronic circuit elements, (https://www.ees.it/wp-content/uploads/2012/01/Nikon_X-RAY-XTV1601.pdf), which performs detailed viewing and analysis of the internal structure of the sample. The device includes a microfocus x-ray tube and a plane-panel detector optically coupled to the tube. The sample is placed on a pallet mounted on a movable horizontal platform located between the tube and the detector. Moreover, in contrast to the analogue described above, the x-ray tube is installed under the table, and the detector is located above the table and is attached to the horizontal guide of the double support U-shaped beam along which it can move. The device, in contrast to the previous analogue, has more degrees of freedom and to obtain an image of the studied region of the sample, five options for moving the components included in it are implemented: the beam with the detector is made with the possibility of smooth deviation in both directions from the coordinate axis Z by an angle of ± 70 °; the platform with the pallet is made with the possibility of reciprocating movement along the coordinate axis Y, and the pallet with the possibility of rotation around the vertical axis Z in the plane of the platform. The technical solution excludes the movement of the platform with the pallet along the X coordinate axis; instead, the device implements the possibility of synchronous movement of the detector and the X-ray tube along its guides along this axis. It is known that in order to obtain a given x-ray magnification of an object, it is necessary to provide the corresponding segments between the anode of the tube and the sample and the sample and the x-ray detector. This feature, in comparison with the above-described analogue, is realized in this device due to the presence of vertical movement of the platform with the pallet, which partially minimized the horizontal dimensions of the device. However, in this design, as in the previous technical solution, the x-ray tube is movable, and its weight is 30 kg and can reach up to 50 kg, which, subject to the requirements for accuracy in positioning the tube, imposes strict requirements on the execution of the mechanical components of the device, their connections with each other and a clear implementation of fairly complex algorithms for synchronizing their work.

The closest technical solution chosen by the applicant as a prototype is the solution according to US patent No. 9442080 (publ. 09/13/2016), which describes a device for obtaining a three-dimensional model of the region of interest of the object of study. The device includes a support frame with a coordinate table located on it. A double-supporting arcuate beam with a guide profile corresponding to the shape of the arc is attached to the frame by means of bearings; counterweights are installed at the ends of the beam. In addition, the device contains a microfocus x-ray source fixedly mounted under the support frame, and the center of the arcuate beam and the detection unit (detector) are located opposite the source location. The detector is fixed in the guide profile of the beam and is configured to move along the profile. The active region of the detector faces the object of analysis, placed on a pallet mounted on the coordinate table, and is optically coupled to an x-ray source. There is a control system for the movement of components of the device, implemented in the form of reciprocating drives, each of which respectively controls the movement of the coordinate table with the pallet in the X direction, in the Y direction and in the Z direction. In addition, there are drives designed to move the detector along the profile the guide of the arcuate beam to which it is attached, and the drive that controls the movement (tilt) of the beam itself. To ensure the inspection of the object and the formation of projections of the image, the device allows you to analyze the object placed on the pallet of the coordinate table, with a given angle of the working beam of the x-ray radiation of the tube. This angle is 140 ° because the detector is shifted along the arc axis relative to the axis of the working beam by an angle of ± 70 ° and the arc itself is also tilted by an angle of ± 70 °. Thus, the detector describes the hemisphere around the object of study.

A common disadvantage of the known devices is the large overall dimensions, in particular horizontal dimensions: when moving an object in the control zone, the device dimensions in X Y coordinates must be determined based on at least double the maximum dimensions of the object under study. (In addition, when rotating the coordinate table (a NIKON METROLOGY NV device), the dimension increases at least two times in the root, which is determined by the radius of the circle into which the overall table is inscribed.) In addition, in the device presented on the NIKON METROLOGY NV website , and in the device according to patent document US No. 9442080, when the beam is tilted with the detection unit placed on it on both sides of the Z axis due to friction, additional vibrations occur in the places where the beam is attached to the support frame, which ultimately leads to distortion of information and ultatov analysis.

A technical problem that can be solved by using the invention is the expansion of the arsenal of microfocus x-ray control devices, an alternative to the prototype device and having lower mass and size indicators with the same coordinate table size for placing the object under study and having high operational reliability. The technical result is to reduce the dimensions without compromising the technical and user characteristics of the x-ray control device.

The specified technical result is achieved in a microfocus x-ray control device, which includes a structure containing a support frame, under which the x-ray tube is fixedly and centrosymmetrically relative to the specified frame. The axis of the working beam of the x-ray radiation of the tube is directed normal to the plane of the support frame. In addition, the device comprises a detecting unit optically coupled to the tube, the detecting unit being located above the support frame and placed on an arcuate beam with the possibility of moving along it to the desired angle of the working beam of the x-ray radiation of the tube. Between the indicated tube and the detecting unit, a coordinate table is mounted on the supporting frame with a pallet located on it for placing an object and made with the possibility of moving along the coordinate axes X, Y and Z. This design is installed and fixed inside the frame, consisting of rigidly connected guides, while an arcuate beam is connected to the upper guide of the frame by means of a fastener fixedly mounted opposite the x-ray tube. The fastening means is configured to rotate the beam around the axis of the working x-ray beam, and the beam itself has working and non-working sections, where the working section is designed to move the detection unit and its length is proportional to the maximum value of the aforementioned angle of the solution, and this angle is limited by the axis of the working x-ray beam radiation and the optical axis of the detection unit.

In the known analog devices, an attempt was made to minimize the overall dimensions of the device while maintaining the size of the pallet by making the beam to move the detector in the form of a two-support U-shaped beam or in the form of a two-support arched beam, as described respectively on the NIKON METROLOGY NV website and in the patent US document No. 9442080. However, the author and applicant have established that the presence of such structural elements is the reason for the significant dimensions of the device. The implementation of the beam as proposed by the author and the applicant will reduce the overall dimensions of the device, significantly increase its reliability by reducing the number of mechanical joints that are provided for in analog devices. The beam in the claimed solution does not rotate, but rotates around the sample using only one node connecting the beam to the frame guide, while the detector, as in analog devices, describes a hemisphere around the object of study, i.e. allows you to perform the same functionality, but with smaller dimensions. An advantage of the claimed technical solution is also the use of a hard drive assembly for attaching the beam. In contrast to the long belt drives traditionally used in such devices, the proposed design is less susceptible to vibrations and, accordingly, provides greater accuracy in the positioning of the arc and, therefore, the detection unit over the entire hemisphere described.

It is advisable that the maximum value of the angle of the solution, limited by the axis of the working beam of x-ray radiation and the optical axis of the detection unit, is not more than 80 °.

It is advisable that the means for connecting the specified beam with the guide frame was made in the form of a rotation bearing.

It is also advisable that

- an adjustment counterweight was placed on the inoperative section of the arcuate beam, which ensures uniform distribution of the load on the rotation bearing when the beam is rotated

- and the counterweight was hollow to accommodate equipment for controlling the movement of the detector.

In a particular embodiment, the device is further provided with vibration damping means to reduce the effect of external vibrations on the device. In this case, the damping means is made, for example, in the form of air springs uniformly installed around the perimeter of the lower guides of the frame, and the number and operating parameters of air springs can vary depending on the required characteristics of the device. The use of damping means is an important factor for such devices, since vibration has a negative effect on maintaining the stability of the parameters of the components of the device, which ultimately affects the quality of the analysis.

The claimed technical result is ensured by the totality of essential features in the framework of the implementation of the appointment, while all component devices characterized by essential features are in constructive unity and functionally interconnected. All components of the device are combined into a single structure, placed and rigidly fixed in the frame, and in the manufacture of the device are interconnected by assembly operations.

To describe the design of the device and its functioning, the following terms are used in the document that are used in this technical field and are given in GOST 20337-74 and GOST 22091.3-84:

the angle of the working beam of the x-ray radiation of the tube - the angle of the working beam, measured in a given plane passing through the axis of the working beam of x-ray radiation of the tube,

the axis of the working beam of the x-ray radiation of the tube is a conditional straight line coinciding with the axis of the cone, limiting the working beam of x-ray radiation of the tube.

In FIG. 1-4 are structural elements of a microfocus device for x-ray inspection, while schematically shown in FIG. 1 is a general view where the coordinate table with the pallet located on it is in the initial position in the plane of the support frame, FIG. 2 is a general view of the device, where the coordinate table with the pallet located on it are in one of the operating positions, FIG. 3 - placement of the device in an X-ray protective housing, FIG. 4 is a schematic illustration of components of a microfocus x-ray control device; positions marked:

1 - microfocus device x-ray control,

2 - frame, consisting of rigidly connected rails,

3 - supporting frame,

4 - microfocus x-ray tube,

5 - detection unit (detector),

6 - arcuate beam with a working (6A) and non-working (6b) sections,

7 - coordinate table,

8 - pallet,

9 - counterweight,

10 - rotation bearing

11 - axis of the working beam of x-ray radiation of the tube 4,

12 - the optical axis of the detection unit 5,

13 - air springs,

14 - object of control (sample),

15 - x-ray protective housing.

Microfocus device x-ray control 1 contains a frame 2 made of rigidly connected guides. A frame is installed inside the frame, which includes a support frame 3 placed on its guides, under which a microfocus x-ray tube 4 of an open type with a shot anode and a focal spot size of not more than 2 μm is fixed and centrosymmetric with respect to the frame. For microfocus tubes of this type, the angle of the working beam of x-ray radiation (in Fig. 4 is the angle of the anode target α), as a rule, is 160 °. The axis 11 of the working beam of x-ray radiation of the tube 4 is directed normal to the plane of the support frame 3. The design also includes a detector 5, optically coupled to the tube 4. The detector 5 is located above the support frame 3 and placed on an arcuate beam 6 with the possibility of movement along it. In this case, the beam 6 is mounted on the upper guide of the frame 2 using the rotation bearing 10, and the bearing 10 should be centered relative to the focus of the x-ray tube 4 (and the plane of the bearing, tube and coordinate table should be parallel). The beam 6 has a working 6a and a non-working 6b sections, where the working section 6a is designed to move the detector 5. The length of the section 6a, along which the detector 5 can move when analyzing the object, is limited by the axis 11 of the working x-ray beam and the optical axis 12 of the detector 5, t .e. proportional to the maximum value of the angle of the solution (in Fig. 4 - the angle ω). Unlike the prototype, where the beam with the detector is tilted, the inventive device rotates around the axis 11, which at an angle ω equal to 45 ° or more provides a larger volume and a larger reconstruction area than in the prototype.

A counterweight 9 can be placed on the non-working section 6b of the beam 6. The counterweight can be hollow to accommodate an electric drive (not shown) that controls the movement of the detector 5 along the working section 6a of the beam. Between the tube 4 and the detector 5, a coordinate table 7 is mounted on the support frame 3 with a pallet 8 located on it to accommodate a sample (not shown). Table 7 by means of drives (not shown in Fig.) Can move along the coordinate axes X, Y and Z. The device provides for the presence of air springs 13 evenly installed around the perimeter of the lower guides of the frame, while the number and operating parameters of the air springs can vary depending from the required characteristics of the device. The device can be installed in the x-ray protective housing 15 (Fig. 3).

The connection of blocks and nodes in the manufacture is carried out by appropriate assembly operations with the formation of a single device.

The functioning of the device is based on the registration of x-ray radiation of the tube 4, which scans the test object, and the radiation intensity is detected by the detector 5. The detector rotates around the object by 360 ° with a deviation of the optical axis 12 from the axis 11 of the x-ray beam of the tube 4 by the angle ω (angle of inclination detector) from 0 to 70 ° (for a tube variant with a working angle of the working beam of x-ray radiation of 160 degrees). The speed of rotation, the speed of movement of the detector is determined by the operator, the size of the test object and the type of study. The coordinate table 7 with the test sample on the pallet 8 can move along the plane of the support frame 3 along the coordinate axes X and Y, as well as along the radiation axis 11 (coordinate axis Z), which allows the selection and change in the process of controlling the spatial resolution and size of the investigated area object.

Thus, a device was created that extends the arsenal of X-ray control devices, which has high operational reliability and, other things being equal, surpasses the presented analogues in the aggregate of such characteristics as overall dimensions, vibration resistance, and mobility.

Claims (9)

1. Microfocus x-ray control device, characterized in that it includes a structure comprising a support frame, under which an x-ray tube is fixedly and centrosymmetrically relative to the frame, the axis of the x-ray beam of which is directed normal to the plane of the support frame, a detection unit optically coupled to the specified tube, while the detection unit is located above the support frame and placed on an arcuate beam with the ability to move along it to the desired angle p X-ray tube alignment working radiation beam between said tube and the detecting unit is mounted on the support frame coordinate table with the pallet disposed thereon to accommodate the control object and adapted to be moved along coordinate axes X, Y and Z, characterized in that the specified design is installed and fixed inside the frame, consisting of rigidly connected guides, while the arcuate beam is connected to the upper guide of the frame using fastening means, fixedly mounted opposite the x-ray tube and providing rotation of the beam around the axis of the working beam of x-ray radiation, and the beam has a working and non-working sections where the working section is designed to move the detection unit, its length is proportional to the maximum value of the mentioned angle solution, and the angle of the solution is limited by the axis of the working beam of the x-ray radiation of the tube and the optical axis of the detection unit. 2. The device according to p. 1, characterized in that the maximum value of the angle of the solution, limited by the axis of the working beam of x-ray radiation and the optical axis of the detection unit, is not more than 80 °. 3. The device according to claim 1, characterized in that the means for connecting said beam to the frame guide is made in the form of a rotation bearing. 4. The device according to claim 1, characterized in that an adjustment counterweight is placed on the non-working section of the arcuate beam, which ensures uniform distribution of the load on the rotation bearing when the beam is rotated. 5. The device according to p. 4, characterized in that the counterweight is hollow to accommodate equipment for controlling the movement of the detector. 6. The device according to p. 1, characterized in that it is additionally equipped with a means of damping vibrations. 7. The device according to p. 6, characterized in that the vibration damping means is made, for example, in the form of air springs uniformly installed around the perimeter of the lower frame guides, while the number and operating parameters of air springs can vary depending on the required characteristics of the device.

Images