This application claims priority from International Application No. PCT/US2011/024849 filed on Feb. 15, 2011, the contents of which are incorporated herein by reference.
The present invention generally relates to the art of motion control, and, more particularly to apparatus for moving an object in a plane. In particular embodiments, the present invention relates to apparatus for moving an object in a plane in a continuous spiral pattern, and in another embodiment, in concentric circles. In a specific, though non-limiting application, the present invention relates to apparatus for moving an object in a plane relative to an imaging device.
Apparatus currently exist for moving an object in a defined plane. These apparatus utilize manual or motorized systems to move the object in one defined direction within the plane, for example, the x direction, and use a second manual or motorized system to move the object in a direction within the plane that is perpendicular to the first, for example, in the y direction. The use of the exemplary “x direction” and “y direction” terms, of course describes movement in an XY plane. It should be appreciated that such terms can be used to define any plane, inasmuch as a plane is a two-dimensional surface, with one dimension being denoted as “x” and the other being denoted as “y”. Such terms are employed in the present disclosure.
The aforementioned apparatus is referred to as an “XY translation stage,” and many configurations are known to those familiar in the art. Typical suppliers include Franklin Mechanical and Control Inc. (Gilroy, Calif., USA) and Physik Instrumente L.P. (Auburn, Mass., USA, also known by PI L.P.). From a review of the translation stages provided by these entities as well as those specifically in U.S. Pat. No. 5,142,791 (Hitachi, Ltd., Tokyo, Japan), U.S. Pat. No. 5,408,750 (Mitutoyo Corporation, Tokyo, Japan), and U.S. Pat. No. 6,809,306 (Olympus Optical Co. Ltd., Tokyo, Japan), it can be seen that the means for managing the movement and tolerances of the movement are varied. It can also be seen that the movement may be manual, or motorized, including but not limited to servo, stepper and piezoelectric motor movement.
An example of the prior art is provided in
In
In
In the current art as shown in
As known, such translation stages are often employed for scanning an object. As used herein, “scanning” is to be understood broadly to refer to defining or analyzing a desired surface area of an object, whether by probe, stylus or electromagnetic beam (e.g., visible light, electron beam, laser, etc). For example, these translation stages are often employed in scanning probe microscopy, scanning beam microscopy, and optical inspection devices and the like. With the aforementioned XY translation stages, in order to scan an entire defined XY plane, the direction of travel must be stopped and reversed when the platform has reach the limit of travel defined by the length of the lead screw. Hence, movement is stopped and direction changed many times during a scan. With the components given in this example, movement would have to be stopped and direction changed approximately 180,000 times to scan a 100×100 mm plane, and the starting, stopping, speed and direction of translational movement must be controlled either by manual operator intervention or by a method of computer motor control of two primary drive mechanisms, one for the X stage and one for the Y stage.
Though the art is populated with various translation stages, there exists room for improvement thereon by providing apparatus for more easily automated translational movement. The present invention is designed to reduce both the motion management and XY translation stage complexity.
In one embodiment, this invention provides an XY translation stage comprising a primary drive mechanism and a stage drive assembly. The primary drive mechanism rotates the stage drive assembly about an axis of rotation. The XY translation stage also includes an object stage that orbits freely in a defined plane without rotation of the object stage out of that defined plane. A stage pin associates the stage drive assembly with the object stage such that rotational movement of the stage drive assembly yields orbital movement of the object stage within the defined plane. The positioning of the stage pin relative to the axis of rotation is adjustable such that the diameter of the orbital movement of the object stage is adjustable.
In another embodiment, this invention provides an XY translation stage comprising a primary drive mechanism and a stage drive assembly. The primary drive mechanism rotates the stage drive assembly about an axis of rotation. The translation stage further includes an object stage and means for retaining the object stage in a defined plane without rotation of the object stage out of the plane. A stage pin associates the stage drive assembly with the object stage, and means are provided for adjusting the position of the stage pin relative to the axis of rotation of the stage drive assembly such that rotational movement of the stage drive assembly yields orbital movement of the object stage within the defined plane.
In particular embodiments in accordance with either of the XY translation stages summarized above, the translation stage further includes a lead screw associated with the stage drive assembly to rotate therewith, the stage pin being threaded onto the lead screw such that rotation of the lead screw causes the stage pin to move along the length of the lead screw to occupy different positions relative to the axis of rotation of the stage drive assembly. In further adaptations of these embodiments, the translation stage further includes a lead screw bevel gear associated with the lead screw and a drive bevel gear that mates with the lead screw bevel gear, the interaction of the lead screw bevel gear and the drive bevel gear serving to rotate the lead screw and thereby cause the stage pin to move along the length of the lead screw. In specific embodiments, the drive bevel gear is stationary and includes a discrete set of bevel gear cogs, the lead screw bevel gear interacting with the drive bevel gear, through the discrete set of bevel gear cogs, once during a single rotation of the stage drive assembly and the stage pin moves a discrete distance due to that interaction. In other specific embodiments, the drive bevel gear provides a complete ring of bevel gear cogs such that the lead screw bevel gear interacts with the drive bevel gear, through the bevel gear cogs, at all times during rotation of the stage drive assembly and the stage pin moves continuously along the length of the lead screw due to that interaction.
For a complete understand of the objects, techniques and structure of the invention, reference should be made to the following detailed description and accompanying drawing wherein:
A first embodiment of an XY translation stage in accordance with this invention is shown in
As seen in
The stage drive assembly 38 consists of a lead screw 42 and a lead screw ball nut 44 which is threaded to move along the length of the lead screw 42 as the lead screw 42 is rotated, the lead screw ball nut 44 moving in one direction along the lead screw 42 when the lead screw 42 is rotated in one direction (e.g. clockwise) and moving in the opposite direction when the lead screw 42 is rotated in an opposite direction (e.g. counterclockwise). The opposed ends of the lead screw 42 are attached to the stage drive assembly 38 by bearings and bearing housings generally shown in
The stage pin 46 is associates the stage drive assembly 38 with the object stage 22 such that rotational movement of the stage drive assembly 38 yields orbital movement of the object stage, with the positioning of the stage pin relative to the axis of rotation of the stage drive assembly defining the diameter of the orbital movement.
A second embodiment of an XY translation stage is show in
The translation stage 120 provides components that cause a continuous movement of the stage pin 146 during rotation of the stage drive assembly 138 by the primary drive mechanism 136. The lead screw 142 is mounted to the stage drive assembly 138 at bearings and bearing housings 143, much like the embodiment of translation stage 20, but one end of the lead screw extends through the bearing mounting to present a bevel gear 150. A mating bevel gear 152 is mounted to a stationary surface, as shown at legs 154. As the stage drive assembly 138 is rotated by the primary drive mechanism 136, the bevel gear 150 is rotated against the stationary mating bevel gear 152, with the result that the lead screw 142 is rotated and the ball nut 144 is moved along the lead screw 142 in proportion to the relative gearing ratio between the bevel gear 150 and the mating bevel gear 152. This in turn results in movement of the object stage 122, and as the stage drive assembly 138 continues to be rotated, a spiral movement pattern is produced.
A third embodiment of an XY translation stage is show in
The translation stage 220 provides components that cause a discrete movement of the stage pin 246 during rotation of the stage drive assembly 238 by the primary drive mechanism 236. The lead screw 242 is mounted to the stage drive assembly 238 at bearings and bearing housings 243, much like the embodiment of translation stage 20, but one end of the lead screw extends through the bearing mounting to present a bevel gear 260. A mating bevel gear 262 is mounted to a stationary surface, as shown at legs 254; however, as compared to the bevel gear 152 of the second embodiment, which produces a spiral movement, this bevel gear 262 is modified such that only a limited number of gear cogs are present. These gear cogs are designated by the numerals 263, 264 and 265. It will be appreciated that, as the stage drive assembly 238 is rotated by the primary drive mechanism 236, the bevel gear 260 will be rotated by the stationary mating bevel gear 262 only when the bevel gear 260 engages and passes over the gear cogs 263, 264 and 265, with the result that the lead screw 242 is only rotated a discrete distance and the ball nut 244 is similarly moved only a discrete distance along the lead screw 242. This in turn results in a discrete movement of the object stage 222, and, with the structure shown for mating bevel gear 262, having only one discrete positioning of gear cogs, as the stage drive assembly 138 continues to be rotated, a movement pattern is produced that causes the object stage to move through discrete concentric circles.
The discrete movement of the ball nut 244 and hence the object stage 222 will depend upon the placement and number of the gear cogs on the mating beveled gear 262. For example, rotation of the bevel gear 260 over a single cog provided in the mating bevel gear 262 would result in a well-defined discrete movement. Continuing this example, if bevel gear 260 has 36 cogs, movement of the bevel gear 260 over a single cog on mating bevel gear 262 would rotate the bevel gear 260 and its attached lead screw 242 1/36 of a turn (10 degrees of rotation). If the mating bevel gear 262 has multiple cogs, as shown at 263, 264 and 265 the resulting rotation of the lead screw would be 3 times 1/36 of a turn or 30 degrees. The lead screw 242 is rotated in proportion to the number of teeth on bevel gear 260 and the number of teeth on mating bevel gear 262 and the object stage 22 is moved respectively though the movement of the ball nut 244, coupling 248 and stage pin 246. Each rotation of the stage drive assembly 238 will move the object stage 222 one step so that a circular pattern is made on each rotation. Each successive rotation will move the platform to successively greater diameters up to the limit permitted by the end of the lead screw 242.
In light of the foregoing, it should thus be evident that the process of the present invention, providing a single primary drive mechanism, continuously scanning XY translation state, substantially improves the art. While, in accordance with the patent statutes, only the preferred embodiments of the present invention have been described in detail hereinabove, the present invention is not to be limited thereto or thereby. Rather the scope of the invention shall include all modifications and variations that fall within the scope of the attached claims.
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/US2011/024849 | 2/15/2011 | WO | 00 | 10/16/2013 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2012/112138 | 8/23/2012 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
3404459 | Redman | Oct 1968 | A |
3638508 | Ikeda | Feb 1972 | A |
3801090 | Gillen | Apr 1974 | A |
5142791 | Kobayashi et al. | Sep 1992 | A |
5279178 | Yanagisawa | Jan 1994 | A |
5408750 | Teng et al. | Apr 1995 | A |
5419410 | Yanagisawa | May 1995 | A |
5481936 | Yanagisawa | Jan 1996 | A |
5499552 | Yanagisawa | Mar 1996 | A |
5595464 | Daniels, Jr. | Jan 1997 | A |
6313945 | Takeuchi | Nov 2001 | B1 |
6327979 | Ochi | Dec 2001 | B1 |
6809306 | Ando et al. | Oct 2004 | B2 |
8087320 | Hsieh | Jan 2012 | B2 |
20090067976 | Xu | Mar 2009 | A1 |
20110070812 | Hsieh | Mar 2011 | A1 |
20110259139 | Wang | Oct 2011 | A1 |
Number | Date | Country |
---|---|---|
28400190 | Nov 1990 | JP |
5196295 | Feb 1995 | JP |
03039808 | May 2003 | WO |
Number | Date | Country | |
---|---|---|---|
20140027967 A1 | Jan 2014 | US |