Fine Movement Stage

Abstract

To provide a fine movement stage capable of increasing the allowable deviation angle in the Z-axis direction. [Solution] A fine motion stage 10 mainly comprises a base 20, and a vertical drive mechanism 50 that is provided between the base and a motion table 30 and can move the motion table vertically toward or away from the base. The vertical drive mechanism comprises three first linear motors 51 for applying a vertical driving force, and three first encoders 52 that are provided between the base and the motion table adjacent to the first linear motors, each of which includes a detection unit 521 and a length measurement unit 522 used to detect the displacement state of the corresponding position of the motion table after being driven by each first linear motor, and defines the linear measurement direction from the detection unit to the length measurement unit as the measurement axis. At least one of the imaginary lines extending in the axial direction of the measurement axis does not pass through the geometric center of the motion table.

Description

[Technical field]

[0001] The present invention relates to precision machining technology, and more particularly to a fine movement stage. [Background technology]

[0002] The high-resolution dynamic positioning mechanism for sample measurement and processing disclosed in US Patent No. 5,999,633 is capable of reducing the overall volume of a conventional Z-axis Tip-Tilt (ZTT) device without interfering with the dynamic performance of the XY stage or related elements, thereby improving upon deficiencies present in the prior art.

[0003] In Patent Document 1, the movement range in the Z-axis direction is controlled by a sheet-like ZTT-θ positioning device, but the factors that affect the tip and tilt in the Z-axis direction are not only limited by the ZTT-θ positioning device, but also by the range that the encoder that provides feedback on the movement position can normally detect. As shown in FIG. 1, the encoders (A, B, C) in Patent Document 1 have detection directions (Sa, Sb, Sc) perpendicular to the tangent of a circle (D) centered on the Z-axis (E) to provide real-time position information. However, when tipping or tilting in the Z-axis direction, a corresponding deviation occurs between the detection end of each encoder and the linear scale, making the detection of the position encoder inaccurate or losing the detection function. As a result, the allowable deviation angle (tip and tilt rotational ranges, also called angle tolerance) on the Z-axis of the technology disclosed in Patent Document 1 is only ±0.05, which is still insufficient. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. WO2005010940A2 Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, a primary object of the present invention is to provide a fine movement stage that can increase the allowable deflection angle in the Z-axis direction. [Means for solving the problem]

[0006] Therefore, in order to achieve the above-mentioned object, the fine movement stage provided by the present invention technically mainly comprises a base and a vertical drive mechanism arranged between the base and a motion table, which can move the motion table vertically toward or away from the base.

[0007] The vertical drive mechanism is arranged distributed between the base and the motion table around the geometric center of the motion table, and comprises three first linear motors for providing the vertical driving force, and three first encoders arranged adjacent to each of the first linear motors and used for detecting displacement of different positions of the motion table after it is driven by the first linear motor, each of which includes a detection unit and a length measuring unit parallel to the detection unit, and which define a linear measurement direction perpendicular to each of the detection units and each of the length measuring units as a measurement axis.

[0008] A technical feature of the present invention is that imaginary lines formed by extending linearly along the axial directions of the multiple measurement axes to the geometric center of the motion table are perpendicular or parallel to each other, and at least one of the imaginary lines does not pass through the geometric center of the motion table.

[0009] Another technical feature of the present invention is that it further includes at least one gravity compensation part, which has a tension spring that is stretched between the base and the motion table, and the horizontal plane on which the connection part between the tension spring and the base is located is higher than the horizontal plane on which the connection part between the tension spring and the motion table is located. [Brief description of the drawings]

[0010] [Figure 1]FIG. 1 is a schematic diagram showing an arrangement of an encoder according to the prior art; [Diagram 2] FIG. 2 is an exploded view of a preferred embodiment of the present invention; [Diagram 3] FIG. 2 is a three-dimensional assembly view of a preferred embodiment of the present invention; [Figure 4] FIG. 2 is a top view of a preferred embodiment of the present invention omitting the motion table; [Diagram 5] FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. [Figure 6] FIG. 2 is a plan view of a guide part according to a preferred embodiment of the present invention; [Figure 7] 1 is a perspective view of a lifting mechanism according to a preferred embodiment of the present invention; [Figure 8] FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. [Figure 9A] FIG. 2 is a schematic diagram showing an encoder arrangement according to a preferred embodiment of the present invention; [Figure 9B] 2 is an example of an encoder arrangement according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First, the description of the direction of the present embodiment is based on the drawings and does not limit the scope of the utility model registration of the present invention. For example, when referring to the direction of gravity, the components shown in the drawings of the present invention are arranged horizontally as a reference, and when the reference changes, the reference also changes accordingly, for example, the reference changes from the direction of gravity to the horizontal line.

[0012] 2 to 5, the fine movement stage 10 provided in the preferred embodiment of the present invention mainly includes a base 20, a motion table 30, a rotary drive mechanism 40, a vertical drive mechanism 50, a guide unit 60, a lifting mechanism 70, and a gravity compensation unit 80.

[0013] The base 20 is provided with a flat seat 21 that can be appropriately attached to an external XY motion stage, thereby enabling the fine movement stage 10 to be driven by the XY motion stage to move in two dimensions on a horizontal plane, and three arc-shaped wall portions 22 are respectively provided on the upper seat surface of the seat 21 so that their concave arc surfaces face each other, thereby defining a cylindrical storage space 23 between each of the arc-shaped wall portions 22.

[0014] The motion table 30 comprises a flat table body 31 located above the seat body 21, and a through hole 32 through which the lifting mechanism is inserted passes through the table body 31 and corresponds coaxially to the storage space 23.

[0015] In this embodiment, the rotary drive mechanism 40 is a rotary motor, which is not shown in detail in the drawings because it is within the scope of known technology. Technically, the rotary drive mechanism 40 is accommodated in the accommodation space 23 and includes an annular stator 41, a hollow cylindrical movable element 42, and a through hole 43 penetrating the cylindrical closed end of the movable element 42. The annular stator 41 is located in the accommodation space 23 and is connected and fixed to the table body 31 at its top end, and the hollow movable element 42 is located coaxially within the stator 41 and has its top end located in the through hole 32, so that a force required for angular displacement is applied to the movable element 42 via the rotary drive mechanism 40, with the vertical direction (Z-axis) being the same as the direction of gravity as the axis of rotation.

[0016] The vertical drive mechanism 50 is interposed between the seat body 21 and the table body 31, is outside the range of the accommodation space 23, and includes three first linear motors 51 and three first encoders 52. In this embodiment, the plurality of first linear motors 51 are exemplified by voice coil motors, but the specific technical content of the voice coil motor is a known technology and is not disclosed in detail in the drawings. Each of the first linear motors 51 is bridged between the base 20 and the motion table 30 at its stator end and mover end, and is used to provide the motion table 30 with a force required for linear displacement in the Z-axis direction, and by varying the motion strokes of the plurality of first linear motors 51, the motion table 30 is tilted in the Z-axis direction to achieve a change in the angular position with respect to the horizontal plane. In this embodiment, the first encoders 52 are conventional optical linear scales, each of which includes a detection unit 521 made of an optical sensor head and a length measuring unit 522 made of a linear scale. The first encoders 52 are adjacent to the first linear motors 51, each of which has its detection unit 521 fixed to the base body 21 and its length measuring unit 522 fixed to the table body 31.

[0017] Referring to FIG. 6, the guide portion 60 includes an integrally molded substantially circular elastic spring 61 and a plurality of fixed blocks 62. The elastic spring includes three first arc-shaped portions 611, three second arc-shaped portions 612, three pairs of elastic portions 613, and three reinforcing arc-shaped portions 614. The first arc-shaped portions 611 are fixed to the top ends of the arc-shaped walls 22 so as to face each other with their concave arc surfaces, and the second arc-shaped portions 612 are fixed to the bottom plate surface of the table body 31 so as to face each other with their concave arc surfaces. The elastic portion 613 pairs are located at both ends of the arc-shaped portions 612, respectively, and are connected to the adjacent first arc-shaped portions 611, thereby forming a Z Each of the reinforcing arc-shaped portions 614 provides a tolerance for displacement of the second arc-shaped portions 612 relative to these first arc-shaped portions on the axis, and is located radially outside the second arc-shaped portions 612 so as to be parallel to the second arc-shaped portions 612, and each of the reinforcing arc-shaped portions 614 bridges between the pairs of elastic portions 613, and each of the pairs of elastic portions 613 includes a first segment 6131 and a second segment 6132 extending radially and spaced apart from each other, and a connecting segment 6133 bridging the extended ends of the first segment 6121 and the second segment 6132.

[0018] The plurality of fixed blocks 62 are respectively in close contact with one side of the plurality of first arc-shaped portions 611 and the plurality of second arc-shaped portions 612, the plurality of first arc-shaped portions 611 are interposed between the corresponding fixed blocks 62 and the ends of the corresponding arc-shaped wall portions 22, the plurality of second arc-shaped portions 612 are interposed between the corresponding fixed blocks 62 and the table body 31, and some of the fixed blocks 62, the plurality of first arc-shaped portions 611 and the plurality of arc-shaped wall portions 22 are fastened by a connecting and fastening means (not shown) such as screw fastening, and some of the fixed blocks 62, the plurality of second arc-shaped portions 612 and the table body 31 are fastened to provide a guide for displacement on the Z axis for the motion table 30.

[0019] 7 and 8, the lifting mechanism 70 is attached to the inner space of the movable element 42 of the rotation drive mechanism, and includes a lower part 71, an upper part 72, three columnar lifting parts 73, a pair of second linear motors 74, a second encoder 75, and a pair of elastic guide members 76. The upper part 72 and the lower part 71 are both sheet-shaped and arranged parallel to each other in the movable element 42, and the plurality of lifting parts 73 are fixed to the upper part 72 at one end and extend coaxially while passing through the plurality of through holes 43 at the other end. In this embodiment, the plurality of second linear motors 74 are specifically exemplified as conventional voice coil motors bridging between the upper part 72 and the lower part 71, and are used to drive the upper part 72 to linearly displace the inner space of the movable element 42, thereby protruding or retracting each of the lifting parts 73 from the corresponding through holes 43. The second encoder 75 is also exemplified as a conventional optical linear scale, and an optical sensor and a linear scale are fixed on the lower portion 71 and the upper portion 72 and are used to detect the displacement position of the upper portion 72. The multiple guide members 76 are bridged between the upper portion 72 and the lower portion 71 and provide an elastic guiding action in the Z-axis direction for the movement of the upper portion 72.

[0020] The gravity compensation unit 80 is used to provide resistance against gravity to the motion table 30 and the rotary drive mechanism 40 and the lift mechanism 70 connected to the motion table, thereby reducing the load of the vertical drive mechanism 50. Specifically, the gravity compensation mechanism 80 includes three tension springs 81 that bridge between the base 20 and the motion table 30. The base 20 further includes three first vertical posts 24 that extend upward from the seat body 21 by an appropriate distance along the Z axis, and the motion table 30 further includes three second vertical posts 33 that extend downward from the table body 31 by an appropriate distance along the Z axis so as to be adjacent to each of the first vertical posts 24, and both ends of the tension springs 81 bridge between the extension ends of the adjacent first vertical posts 24 and the extension ends of the second vertical posts 33, thereby providing the above-mentioned effect of resistance against gravity. Furthermore, in another embodiment, the plurality of first vertical posts 24 are made slidable on the base body 21, i.e., the plurality of first vertical posts 24 can be slidably mounted on the base body 21, so that by changing the position of the plurality of first vertical posts 24, the distance between adjacent second vertical posts 33 can be adjusted, and the resistance ability against gravity that can be achieved by changing the tension of the plurality of tension springs 81 can be adjusted.

[0021] In consideration of the above, to further describe the technical features of the present invention, continue to refer to FIG. 9A. In this embodiment, first, a linear measurement direction from the detection unit 521 to the length measurement unit 522 of the plurality of first encoders 52 is defined as a measurement axis S. The plurality of measurement axes S extend linearly from their own axes to the geometric center E' of the motion table 30 to form imaginary straight lines S' which are perpendicular or parallel to each other, and at least one of the imaginary straight lines S' does not pass through the geometric center of the motion table 30. In this embodiment, the allowable Z-axis tip and tilt rotational ranges of the plurality of first encoders 52 can reach ±0.065 degrees, which increases the angle tolerance by 30% compared to the prior art, and the effect is undoubtedly significant.

[0022] In another embodiment, when the measurement direction of the measurement axis S is incorporated into the analysis, the condition for making different virtual straight lines S' perpendicular or parallel in the above description can be further exemplified as shown in Fig. 9B. When a straight line passing through the geometric center of the motion table 30 and parallel or perpendicular to any of the multiple virtual straight lines S' is defined as the x-axis, the included angles between the multiple measurement axes S and the x-axis can be independently 0 degrees θ1, 90 degrees θ2, 180 degrees θ3, or 270 degrees θ4, and any or all of the above angles can be arbitrarily selected and combined, and the effect is the same as that of this embodiment. [Explanation of symbols]

[0023] 10 Micromotion Stage 20 Base 21 Seat 22 Circular wall 23 Containment Space 24 First Vertical Post 30 Exercise Table 31 Table body 32 Through hole 33 Second Vertical Post 40 Rotational drive mechanism 41 Stator 42 Mover 43 Through hole 50 Vertical drive mechanism 51 First linear motor 52 1st Encoder 521 Detection unit 522 Length measuring section 60 Guide part 61 Elastic Spring 611 First arc-shaped part 612 Second arc-shaped part 613 Elastic Part 6131 1st Segment 6132 Second Segment 6133 Combined Segments 614 Reinforced arc-shaped section 62 Fixed Block 70 Lifting Mechanism 71 Lower 72 Top 73 Lifting section 74 Second Linear Motor 75 Second Encoder 76 Guide member 80 Gravity compensation section 81 Tension Spring A, B, C, Encoder E, center E' center D.Circular S, measurement axis S' Virtual line Sa, Sb, Sc detection direction θ1, θ2, θ3, θ4 included angle

Claims

1. Exercise table and With the base, a motion table provided between the base and the motion table, the motion table being capable of moving in a vertical direction toward or away from the base; three first linear motors disposed in a distributed manner between the base and the motion table around a geometric center of the motion table for applying a driving force in the vertical direction; three first encoders provided adjacent to each of the first linear motors, each of which is used to detect a displacement of a different position of the motion table after being driven by the first linear motor, each of which includes a detection portion and a length measuring portion parallel to the detection portion, and each of which defines a measurement direction perpendicular to each of the detection portions and each of the length measuring portions as a measurement axis; a vertical drive mechanism including: A fine movement stage comprising: Imaginary straight lines extending linearly to the geometric center of the motion table along the axial directions of the plurality of measurement axes are perpendicular or parallel to each other, and at least one of the imaginary straight lines does not pass through the geometric center of the motion table. Micromotion stage.

2. The fine movement stage of claim 1 , wherein each of the first linear motors is a voice coil motor.

3. 3. The fine movement stage according to claim 2, wherein a straight line that passes through a geometric center of the motion table and is parallel or perpendicular to any one of the plurality of virtual straight lines is defined as an x-axis, and the angles between the plurality of measurement axes and the x-axis are each independently 0 degrees, 90 degrees, 180 degrees, or 270 degrees.

4. The fine movement stage according to claim 1 , wherein each of the plurality of first encoders is an optical linear scale.

5. 5. The fine movement stage according to claim 1, further comprising at least one gravity compensation unit that includes a tension spring that is stretched between the base and the motion table and that causes a horizontal plane on which a connection portion between the tension spring and the base is located to be higher than a horizontal plane on which a connection portion between the tension spring and the motion table is located.

6. the base includes a seat and at least one first vertical post extending upward from the seat in a direction of gravity; The motion table includes a table body and at least one second vertical post extending downward from the table body in a direction of gravity and adjacent to the first vertical post; 6. The fine movement stage according to claim 5, wherein both ends of the tension spring are bridged between the extended ends of the first vertical post and the extended ends of the second vertical post.

7. The fine motion stage of claim 6 , wherein the first vertical post is positioned so that it can slide on the base.

8. The present invention further includes a guide portion including an elastic spring and disposed between the base and the motion table, the elastic spring being three first arcuate portions each fixed to the base; three second arc-shaped portions fixed to the motion table, the second arc-shaped portions intersecting with the first arc-shaped portions with the geometric center of the motion table as a center of curvature; three pairs of elastic portions each located at both ends of the second arc-shaped portions and connected to the adjacent first arc-shaped portions to provide a tolerance for displacement of the second arc-shaped portions relative to the first arc-shaped portions in the vertical direction; The fine movement stage according to any one of claims 1 to 4, comprising:

9. The fine movement stage according to claim 8 , wherein the elastic spring further comprises three reinforcing arc-shaped portions having a sheet-like shape, the reinforcing arc-shaped portions bridging between the pairs of elastic portions.

10. 5. The fine movement stage according to claim 1, further comprising a lifting mechanism provided on the base, the lifting mechanism comprising a lifting portion for lifting an object on the motion table and moving it away from the motion table or returning the object to the motion table.

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