A device for automatically correcting the level of a platform

Abstract

The present invention discloses a device for automatically correcting the level of a platform, which includes a fixed seat, a movable platform, a concentric bearing, and a plurality of eccentric pressing mechanisms; the movable platform is disposed above the fixed seat with adjustable level, and a plurality of tension springs are connected between the bottom of the movable platform and the fixed seat; the concentric bearing is rotatably disposed on the fixed seat and abuts against the bottom of one corner of the movable platform; the plurality of eccentric pressing mechanisms are all disposed on the fixed seat and are located beside the lower sides of the remaining corners of the movable platform, and each eccentric pressing mechanism includes a rotating shaft, a servo motor, and an eccentric bearing. By measuring and calculating the height differences of the four corners of the movable platform, the program converts and drives the corresponding servo motors to control the rotation of the eccentric bearings, so as to complete the height adjustment to achieve the level within the standard. After the automation of the level correction, it can greatly liberate human resources, save labor costs, reduce maintenance time, and also avoid various risks caused by human operation errors.

Description

Technical Field

[0001] The present invention relates to the technology of automated equipment, and in particular to a device for automatically correcting the level of a platform. Background Art

[0002] In the semiconductor packaging industry, automated equipment is increasingly applied to the production process. The higher the degree of automation of the equipment, the more manpower costs, time costs, and maintenance costs can be saved. At the same time, it can also minimize various problems caused by human operation errors.

[0003] Currently, various equipment in the semiconductor packaging industry more or less involves the problem of the level of the platform. The quality of the platform level is related to the quality, yield, equipment stability, and operation rate of the product. And the technology for correcting the level of the platform is also widely used in semiconductor packaging equipment. Taking the Flip Chip process in the camera industry as an example, if the platform level is not adjusted well, it will cause the substrate to be horizontally inclined. During the chip welding process, partial virtual welding of the pins will occur, resulting in electrical defects. And the tilt of the photosensitive chip package will also cause the imaging quality to deteriorate, affecting the product yield. The current platform level correction technologies all rely on manual adjustment of the platform height to achieve level correction. The only difference is the different mechanical structures for realizing height adjustment. Manual correction has high requirements for the professionalism and proficiency of the operator, and it takes repeated attempts many times to achieve the ideal effect. The time spent during the correction process is too long, affecting the operation rate of the equipment. Summary of the Invention

[0004] In view of this, in view of the deficiencies of the existing technology, the main purpose of the present invention is to provide a device for automatically correcting the level of a platform, which can effectively solve the problems of long time and low efficiency in the existing manual correction of the platform level.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A device for automatically correcting the level of a platform includes a fixed seat, a movable platform, a concentric bearing, and a plurality of eccentric pressing mechanisms; the movable platform is disposed above the fixed seat with adjustable level, and a plurality of tension springs are connected between the bottom of the movable platform and the fixed seat; the concentric bearing is rotatably disposed on the fixed seat and abuts against the bottom of one corner of the movable platform; the plurality of eccentric pressing mechanisms are all disposed on the fixed seat and beside the lower sides of the remaining corners of the movable platform. Each eccentric pressing mechanism includes a rotating shaft, a servo motor, and an eccentric bearing. The rotating shaft is rotatably installed on the fixed seat, the servo motor is fixed on the fixed seat and drives the rotating shaft to rotate back and forth, the eccentric bearing is fixed on the rotating shaft and is driven to rotate by the rotating shaft, and the eccentric bearing abuts against the bottom of the corresponding corner of the movable platform.

[0007] Preferably, there are four tension springs, which are distributed at the bottoms of the four corners of the movable platform.

[0008] Preferably, positioning holes are formed in the fixed seat, a positioning pin is fixed to the bottom surface of the movable platform, and the positioning pin is inserted into the positioning hole.

[0009] Preferably, there are four positioning pins evenly arranged along the periphery of the movable platform. Correspondingly, there are also four positioning holes. Each positioning pin is respectively inserted into the corresponding positioning hole.

[0010] Preferably, a rubber sleeve is fixed to the periphery of the positioning hole, and the rubber sleeve is sleeved on the outer side surface of the positioning pin.

[0011] Preferably, there are three eccentric pressing mechanisms, which are distributed at three edges of the fixed seat and press against three corners of the movable platform.

[0012] Preferably, the rotating shaft has a threaded section, a movable seat is screwed to the threaded section, the movable seat is driven by the threaded section to move back and forth along the axial direction of the rotating shaft. There are three trigger pieces on the movable seat, and positive limit sensors, origin sensors and negative limit sensors are arranged on the fixed seat in sequence along the axial direction of the rotating shaft. The three trigger pieces move close to or away from the corresponding sensors respectively.

[0013] Preferably, the threaded section is located between the eccentric bearing and the servo motor.

[0014] Preferably, a slide rail is arranged on the fixed seat, and the movable seat is slidably mounted on the slide rail and moves back and forth along the slide rail.

[0015] Preferably, an installation groove is arranged on the fixed seat, and the positive limit sensor, the origin sensor and the negative limit sensor are all arranged in the installation groove with adjustable positions.

[0016] Compared with the prior art, the present invention has obvious advantages and beneficial effects. Specifically, it can be seen from the above technical solutions that:

[0017] By measuring and calculating the height differences of the four corners of the movable platform, the program converts and drives the corresponding servo motor to control the rotation of the eccentric bearing to complete the height adjustment to achieve the levelness within the standard. After the levelness correction is automated, it can greatly liberate manpower, save labor costs, reduce maintenance time, and also avoid various risks caused by human operation errors.

[0018] To more clearly illustrate the structural features and functions of the present invention, the present invention will be described in detail below in conjunction with the drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1It is a three-dimensional assembly schematic diagram of a preferred embodiment of the present invention;

[0020] Figure 2 It is an exploded view of a preferred embodiment of the present invention;

[0021] Figure 3 It is an enlarged schematic diagram of the eccentric pressing mechanism in a preferred embodiment of the present invention;

[0022] Figure 4 It is an enlarged schematic diagram of the eccentric pressing mechanism from another angle in a preferred embodiment of the present invention;

[0023] Figure 5 It is a schematic diagram of the rotation principle of the eccentric bearing in a preferred embodiment of the present invention.

[0024] Explanation of the attached drawing reference numerals:

[0025] 10. Fixed seat 11. Positioning hole

[0026] 12. Rubber sleeve 13. Slide rail

[0027] 14. Installation groove 20. Movable platform

[0028] 21. Positioning pin 30. Concentric bearing

[0029] [[ID=�4]]40. Eccentric pressing mechanism 41. Rotating shaft

[0030] 411. Threaded section 42. Servo motor

[0031] 43. Eccentric bearing 44. Movable seat

[0032] 441. Trigger piece 50. Tensile spring

[0033] 61. Positive limit sensor 62. Origin sensor

[0034] 63. Negative limit sensor Detailed implementation manners

[0035] Please refer to Figures 1 to 5 As shown, it shows the specific structure of a preferred embodiment of the present invention, including a fixed seat 10, a movable platform 20, a concentric bearing 30, and a plurality of eccentric pressing mechanisms 40.

[0036] The fixed seat 10 is of a square plate structure. The movable platform 20 is disposed above the fixed seat 10 with adjustable level. A plurality of tension springs 50 are connected between the bottom of the movable platform 20 and the fixed seat 10; in this embodiment, there are four tension springs 50, which are distributed at the bottoms of the four corners of the movable platform 20 to maintain the stability of the force on the movable platform 20; moreover, a positioning hole 11 is formed on the fixed seat 10, a positioning pin 21 is fixed on the bottom surface of the movable platform 20, and the positioning pin 21 is inserted into the positioning hole 11. Also, there are four positioning pins 21 evenly arranged along the periphery of the movable platform 20, and correspondingly there are also four positioning holes 11, and each positioning pin 21 is respectively inserted into the corresponding positioning hole 11 to fix the position of the movable platform 20. A linear bearing (not shown in the figure) is provided inside the positioning hole 11 to make the positioning pin 21 move up and down without friction; in addition, a rubber sleeve 12 is fixed on the periphery of the positioning hole 11, and the rubber sleeve 12 is sleeved on the outer side surface of the positioning pin 21 to allow a certain margin of inclination of the positioning pin 21 of the movable platform 20 during horizontal calibration.

[0037] The concentric bearing 30 is rotatably disposed on the fixed seat 10 and abuts against the bottom of one corner of the movable platform 20. The concentric bearing 30 is a concentric shaft, that is, a fixed shaft, and its height does not change with the rotation of the bearing.

[0038] The plurality of eccentric pressing mechanisms 40 are all disposed on the fixed seat 10 and are located beside the lower sides of the remaining corners of the movable platform 20. Each eccentric pressing mechanism 40 includes a rotating shaft 41, a servo motor 42 and an eccentric bearing 43. The rotating shaft 41 is rotatably installed on the fixed seat 10. The servo motor 42 is fixed on the fixed seat 10 and drives the rotating shaft 41 to rotate back and forth. The eccentric bearing 43 is fixed on the rotating shaft 42 and is driven to rotate by the rotating shaft 41, and the eccentric bearing 43 abuts against the bottom of the corresponding corner of the movable platform 20. The eccentric bearing 43 is an eccentric shaft, that is, a variable shaft, and its height can change with the rotation with the eccentric circle as the rotation axis. The height change of the eccentric bearing 43 is the position change of the center of the bearing, and its change range is related to the distance between its two centers. Assuming the distance between the two centers of the eccentric bearing 43 is d, the sum of the adjustable minimum to maximum height of the eccentric bearing 43 is 2d. When the two centers are on the zero-degree horizontal line, the height of the eccentric bearing 43 is the same as the height of the concentric bearing. When the two centers are on the 90-degree vertical line, the eccentric bearing 43 can be in the lowest or highest position.

[0039] In this embodiment, there are three eccentric pressing mechanisms 40, which are distributed on three edges of the fixed seat 10 and press against three corners of the movable platform 20.

[0040] Further, the rotating shaft 41 has a threaded section 411, on which a movable seat 44 is screwed. The movable seat 44 is driven by the threaded section 411 to move back and forth along the axial direction of the rotating shaft 41. The movable seat 44 has three trigger pieces 441, and on the fixed seat 10, a positive limit sensor 61, a home sensor 62 and a negative limit sensor 63 are arranged in sequence along the axial direction of the rotating shaft 41. The three trigger pieces 441 move to approach or move away from the corresponding sensors respectively. The positive limit sensor 61 is used for limiting when the servo motor 42 rotates forward to the highest position of the eccentric bearing 43; when the two centers of the eccentric bearing 43 are at the zero-degree horizontal line, the height of the eccentric bearing 43 is the same as that of the concentric bearing 30. The purpose of the home sensor 62 is to make the four bearings at the same horizontal height when the servo motor 42 performs a home reset; the negative limit sensor 63 is used for limiting when the servo motor 42 rotates reversely to the lowest position of the eccentric bearing 43. In this embodiment, the threaded section 411 is located between the eccentric bearing 43 and the servo motor 42. On the fixed seat 10, a slide rail 13 is provided, and the movable seat 44 is slidably mounted on the slide rail 13 and moves back and forth along the slide rail 13; further, on the fixed seat 10, a mounting groove 14 is provided, and the positive limit sensor 61, the home sensor 62 and the negative limit sensor 63 are all arranged in the mounting groove 14 with adjustable positions.

[0041] The working principle of this embodiment is described in detail as follows:

[0042] During use, a fixture for fixing a substrate (product) can be installed on the movable platform 20 of this device. Due to the self-weight of the fixture or the different installation methods of the operator, the movable platform 20 may be tilted. At this time, it is necessary to correct the levelness of the movable platform 20.

[0043] Before calibration, it is necessary to reset the origin positions of the servo motors 42 of the three eccentric pressing mechanisms 40 so that the concentric bearing 30 and the three eccentric bearings 43 are at the same horizontal height. The height data of the four corners of the movable platform 20 (i.e., the positions corresponding to the four bearings) are collected. The data collection method can be different according to the requirements of different devices. It can be installing an infrared ranging sensor above the movable platform 20 or using the servo motor to measure the height. Taking the flip chip process of the mobile phone camera as an example, this device measures the height of each point of the movable platform 20 with the servo motor of the bondhead, and no specific requirements are made here. Among the bearings corresponding to the four corners of the movable platform 20, the concentric bearing 30 is a fixed shaft and cannot be adjusted, and the three eccentric bearings 43 are adjustable bearings. Let the height data of the four corners collected be a, b, c, and d. a corresponds to the concentric bearing 20, and b, c, and d correspond to the three eccentric bearings 43 respectively. Calculate the difference between the height corresponding to each of the three eccentric bearings 43 and the height corresponding to the concentric bearing 30, which is the corresponding height of the eccentric bearing that needs to be adjusted. The difference between b and a is the height that the first eccentric bearing needs to be adjusted. The difference between c and a is the height that the second eccentric bearing needs to be adjusted. The difference between d and a is the height that the third eccentric bearing needs to be adjusted. Assuming b > a, it means that the height of the second eccentric bearing is lower than that of the concentric bearing 30, and the height of the second eccentric bearing needs to be increased. Therefore, when the two values are subtracted and the result is positive, it means that the corresponding servo motor 42 rotates forward, and the eccentric bearing 43 needs to be raised; when the two values are subtracted and the result is negative, it means that the servo motor 42 rotates in reverse, and the eccentric bearing 43 needs to be lowered. After the horizontal adjustment of the movable platform 20 is completed, the height of the four corners of the movable platform 20 will be measured again. If the height difference is less than the set standard range, it means that the leveling of the movable platform 20 is completed. Taking the flip chip process of the mobile phone camera as an example, the error of the leveling of the movable platform 20 needs to be less than 20 μm to meet the process requirements, that is, when the measured height difference of the movable platform 20 is less than 20 μm, it means that the calibration is completed.

[0044] The height difference that the eccentric bearing 43 needs to be adjusted needs to be converted into the number of pulses output by the servo motor 42. The servo motor 42 rotates a fixed angle with one pulse signal. The accuracy of the servo motor 42 depends on the number of lines of the encoder. Let the number of lines of the encoder be n. Then the number of pulses required for the servo motor 42 to make one full rotation (360°) is 2 to the power of n, that is, 2^n. Then the number of pulses required for the servo motor 42 to rotate 1° is 2^n / 360. Let the number of pulses required for the servo motor 42 to rotate an angle of α be m, then it can be obtained that:

[0045] (1) m = α * 2^n / 360;

[0046] Let the distance between the two centers of the eccentric bearing 43 be d. Then the maximum range of the height change of the eccentric bearing 43 is the diameter 2d of the circle with d as the radius. The relationship between the height change h and the rotation angle α of the servo motor 42 is:

[0047] (2)h=sin∠α*d;

[0048] Using inverse trigonometric functions we can get:

[0049] (3)∠α=arcsin(h / d);

[0050] From the above three equations, it can be concluded that the relationship between the number of pulses m required for the rotation angle of the servo motor 42 and the change in height h is:

[0051] (4)m=arcsin(h / d)*2^n / 360;

[0052] (5)h=sin∠(360m / 2^n)*d;

[0053] Therefore, the relationship between the height change of the movable platform 20 during horizontal adjustment and the servo motor 42 can be directly defined in the program.

[0054] The design focus of the present invention is: by measuring and calculating the height difference of the four corners of the movable platform, the program converts and drives the corresponding servo motor to control the rotation of the eccentric bearing to complete the height adjustment to achieve the horizontality within the standard. After the horizontality correction is automated, it can greatly liberate manpower, save labor costs, reduce maintenance time, and avoid various risks caused by human operational errors.

[0055] The technical principles of the present invention have been described above with reference to specific embodiments. These descriptions are intended solely to illustrate the principles of the present invention and are not to be construed in any way as limiting the scope of protection of the present invention. Based on the explanations herein, those skilled in the art will readily conceive of other specific embodiments of the present invention without inventive effort, and such embodiments will fall within the scope of protection of the present invention.

Claims

1. A device for automatically correcting the levelness of a platform, characterized by: The invention comprises a fixed seat, a movable platform, a concentric bearing and a plurality of eccentric pressing mechanisms; the movable platform is arranged above the fixed seat with adjustable horizontality, and a plurality of tension springs are connected between the bottom of the movable platform and the fixed seat; the concentric bearing is rotatably arranged on the fixed seat and abuts the bottom of one corner of the movable platform; the plurality of eccentric pressing mechanisms are all arranged on the fixed seat and are located below and to the sides of the remaining corners of the movable platform, each eccentric pressing mechanism comprises a rotating shaft, a servo motor and an eccentric bearing, the rotating shaft is rotatably mounted on the fixed seat, the servo motor is fixed on the fixed seat and drives the rotating shaft to rotate back and forth, the eccentric bearing is fixed on the rotating shaft and is driven to rotate by the rotating shaft, and the eccentric bearing abuts the bottom of the corresponding corner of the movable platform; the height of the eccentric bearing can change with the rotation with the eccentric circle as the rotating axis; An infrared ranging sensor is installed on the movable platform to measure the height of the corner of the movable platform, and the height of the eccentric bearing is adjusted accordingly according to the difference in height between the corner of the movable platform corresponding to the eccentric bearing and the corner of the movable platform corresponding to the concentric bearing.

2. The device for automatically correcting the levelness of a platform according to claim 1, wherein: There are four tension springs distributed at the bottoms of the four corners of the movable platform.

3. The device for automatically correcting the levelness of a platform according to claim 1, wherein: A positioning hole is provided on the fixing seat, and a positioning pin is fixed on the bottom surface of the movable platform, and the positioning pin is inserted into the positioning hole.

4. The device for automatically correcting the levelness of a platform according to claim 3, wherein: There are four positioning pins evenly arranged along the periphery of the movable platform, and there are also four corresponding positioning holes. Each positioning pin is inserted into the corresponding positioning hole.

5. The device for automatically correcting the levelness of a platform according to claim 3, wherein: A rubber sleeve is fixed to the periphery of the positioning hole, and the rubber sleeve is sleeved on the outer surface of the positioning pin.

6. The device for automatically correcting the levelness of a platform according to claim 1, wherein: There are three eccentric pressing mechanisms, which are distributed on the three edges of the fixed seat and press the three corners of the movable platform.

7. The device for automatically correcting the levelness of a platform according to claim 1, wherein: The rotating shaft has a threaded section, and a movable seat is threadedly connected to the threaded section. The movable seat is driven by the threaded section to move back and forth along the axial direction of the rotating shaft. The movable seat has three trigger pieces, and the fixed seat is provided with a positive limit sensor, an origin sensor and a negative limit sensor arranged in sequence along the axial direction of the rotating shaft. The three trigger pieces move closer to or away from the corresponding sensors respectively.

8. The device for automatically correcting the levelness of a platform according to claim 7, wherein: The threaded section is located between the eccentric bearing and the servo motor.

9. The device for automatically correcting the levelness of a platform according to claim 7, wherein: The fixed seat is provided with a slide rail, and the movable seat is slidably mounted on the slide rail and moves back and forth along the slide rail.

10. The device for automatically correcting the levelness of a platform according to claim 7, wherein: The fixing seat is provided with a mounting groove, and the positive limit sensor, the origin sensor and the negative limit sensor can be arranged in the mounting groove in an adjustable manner.

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