CN102169219B - Radial adjustment device for optical system - Google Patents

Abstract

A radial adjustment device for an optical system. The optical system includes a base and a movable part. The radial adjustment device is arranged between the base and the movable part to make the movable part move relative to the base in the radial direction. The radial adjustment device includes: a radial drive mechanism, which includes a bow-shaped spring body and a drive motor that drives the bow-shaped spring body. When the push rod of the drive motor advances, the middle part of the bow-shaped spring body is deformed by the thrust force to push the movable part. Radial movement; a ball plunger arranged radially of the movable part, which includes an elastic body to provide a preload between the movable part and the base, so that the ball plunger cooperates with the bow spring body to form a balance , the balance achieves radial movement and is capable of recovery. The radial adjustment device of the present invention includes a bow spring body and a ball plunger, and the bow spring body and the ball plunger cooperate to form a balance. Therefore, radial movement and return can be performed by utilizing the elasticity of the bow-shaped spring body and the ball plunger, and the structure is simple.

Description

Radial adjustment device for optical system

technical field

The invention relates to photolithography equipment, in particular to a movable lens adjusting device in the photolithography equipment.

Background technique

In optical instruments and optical equipment, especially projection objectives in advanced lithography equipment, smaller and smaller wave aberrations and distortions are required. Due to the installation accuracy error of the lens and the thermal effect caused by the ambient temperature on the lens, the imaging quality of the lens on the object will be deteriorated. In addition, in the projection objective lens, it is also necessary to compensate for changes in wave aberration and distortion caused by various environments and other factors in real time. In order to solve this kind of problems, one or several adjustable lenses are generally used to compensate installation errors and thermal effect errors.

There are many ways to realize the adjustable lens in the exposure equipment. The adjustment structure generally adopts linear guide rail or reed as the guiding mechanism; uses worm gear and worm, ball screw, cam, etc. as the lifting mechanism.

No. 6400516 U.S. Patent No. 6400516 named "Dynamic Optical Mirror Group" mentions a lens adjustment mechanism, in which a plurality of support pads are distributed on the outer circle of the lens, and a plurality of support pads are correspondingly distributed on the inner circle of the lens holder. A clamping bracket, the clamping bracket can support or limit the movement of the lens in a direction parallel to the optical axis of the assembly or along a tangential direction of the supporting pad.

US Patent No. 6574053 entitled "Dynamic Alignment Structure for Placing Axially Aligned Components in a Cylindrical Body" presents a dynamic alignment structure for assembling a plurality of axially aligned mirror mounts into a lens barrel , the alignment structure includes an annular gasket with three bosses on each of its two sides. The ring spacer can be rotated axially along the lens barrel to position the support boss to control the axial alignment of the lens mount. The dynamic alignment structure includes a mirror base, and several flexible elements are evenly distributed on its outer circle, which can be used for radial adjustment of the mirror base and can facilitate the assembly of the lens barrel.

A common feature of these patents is that they can drive the lens to adjust in the direction of the optical axis and in the radial direction, but the structure is relatively complicated, the adjustment accuracy is not high, and the most important thing is that they are not driven by a motor. For the high-precision lithography objective lens, for the movable adjustment of some lenses, some need to be adjusted in the assembly stage, and some need to be adjusted in real time in actual work to perform thermal compensation.

Contents of the invention

In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to provide a radial motor with high precision, compact structure, low cost, stable operation, accurate positioning, good repeatability, and real-time adjustment by motor. Adjustment device.

To achieve the above object, the present invention provides a radial adjustment device for an optical system. The optical system includes a base and a movable part. The radial adjustment device is arranged between the base and the movable part to make the movable part move relative to the base in the radial direction. The radial adjustment device includes: a radial drive mechanism, including a bow-shaped spring body and a drive motor for driving the bow-shaped spring body, wherein one end of the bow-shaped spring body is fixed on the base, and the other end is connected to the movable moving parts, and the middle position of the arched part of the bow spring body is in direct contact with the push rod of the drive motor; and wherein when the push rod of the drive motor advances, the middle part of the bow spring body is pushed When deformation occurs, the end connected to the movable part protrudes forward to form a radial tension, thereby pushing the movable part to move radially; the ball arranged along the radial direction of the movable part A head plunger, one end of which is fixed on the circumferential surface of the base, and the other end is in contact with the movable part, wherein the ball plunger includes an elastic body to provide contact between the movable part and the base Pre-tightening force, so that the ball plunger cooperates with the bow-shaped spring body to form a balance, and the balance achieves the radial movement and can be restored.

Preferably, one end of the arcuate spring body is fixed to the base by a pin, and the other end is in direct contact with the movable part.

Preferably, the axial-radial conversion ratio of the arcuate spring body is set to 5:1.

Preferably, the ball plunger is a set screw with a built-in compression spring.

Preferably, the pre-tightening force depends on the compression distance and stiffness of the spring.

Preferably, the movable part is a circular lens, and the radial adjustment device includes two radial drive mechanisms distributed at intervals of 120 degrees and a ball plunger.

Preferably, the movable component is a circular lens, and the radial adjustment device includes two radial drive mechanisms and two ball plungers distributed at intervals of 90 degrees.

Preferably, the adjustment device further includes an axial drive mechanism for axially moving the movable lens, and the axial drive mechanism includes three axial ball studs arranged along the axial direction of the movable part plug, and is driven by the drive motor.

Preferably, one end of the axial ball plunger is arranged on the lower end surface of the movable part, and the other end is in contact with the base.

The radial adjustment device of the present invention includes a bow spring body and a ball plunger, and the bow spring body and the ball plunger cooperate to form a balance. Therefore, radial movement and recovery can be performed by utilizing the elasticity of the bow-shaped spring body and the ball plunger, and the structure is simple.

Description of drawings

Figure 1 is a perspective view of a radial adjustment device;

Fig. 2 is a sectional view of the radial adjustment device;

Fig. 3 is the schematic diagram of bow spring body;

Figure 4 shows an example of a radial adjustment device;

Fig. 5 shows another example of a radial adjustment device.

Detailed ways

Referring to the accompanying drawings of embodiments of the invention, the invention will be described in more detail below. However, this invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

The structure of the radial adjustment device according to the present invention will now be described with reference to FIGS. 1 to 3 .

The radial adjustment device of the present invention is used in an optical system. For the purpose of illustration, the optical system of the present invention includes a main lens barrel 1 and a circular movable lens group 2 . The main lens barrel 1 is the basis for installation of the radial adjustment device of the present invention, and provides a horizontal installation reference for the movable mirror group 2 and the fixed mirror groups 3 and 4 . The movable mirror group 2 includes a movable mirror 21 and a movable mirror base 23 . The movable mirror 21 is fixed on the movable mirror base 23 by optical glue. The main barrel 1 is an example of a base. The movable mirror group 2 is an example of a movable member.

As those skilled in the art should understand, the optical system may also have other components, for example, it may also include a fixed mirror group 3 and a fixed mirror group 4 . The lenses 31 and 41 of the fixed lens groups 3 and 4 are respectively fixed on the lens barrels 33 and 43 of the fixed lens groups by optical glue. The fixed mirror group lens barrels 33 and 34 are installed on the main lens barrel 1 by fixing screws, and the fixed mirror group lenses 31 and 41 are on the same optical axis as the main lens barrel 1 . The fixed mirror groups 3 and 4 are an example of fixed parts.

Thus, the radial adjustment device of the present invention is intended to allow coaxial radial adjustment of said movable part with respect to said base (and fixed part, if present).

It should be understood that the optical system may also have other structures.

The radial adjustment device includes a radial drive mechanism 8 . The radial driving mechanism 8 includes a bow-shaped spring body and a drive motor 6 for driving the spring body. As shown in FIG. 3 , the arcuate spring body comprises a pin 7 . Referring to FIGS. 2 and 3 , one end of the bow-shaped spring body is fixed on the main lens barrel 1 by a pin 7 , and the other end is in direct contact with the outer circle of the mirror holder 23 . The middle position of the arched portion of the arched spring body is in direct contact with the push rod of the drive motor 6 . When the push rod of the motor advances, the middle part of the bow-shaped spring body is deformed by the thrust, and protrudes forward at the end close to the mirror holder 23, and forms a radial tension, thereby pushing the mirror holder 23 to radially translate.

The radial adjustment device also includes a ball plunger 5 . The ball plunger 5 is a set screw with a built-in compression spring. The ball plunger 5 is arranged between the movable mirror group 2 and the main lens barrel 1 along the radial direction of the movable mirror group 2 . Specifically, one end of the ball plunger 5 is fixed in a radial screw hole on the peripheral surface of the main lens barrel 1 , and the other end is in contact with the movable lens group 2 . A certain pretightening force is guaranteed when the ball plunger 5 is installed, and the magnitude of the pretightening force depends on the compression distance of the inner spring of the ball plunger 5 and the stiffness K of the inner spring. Thus, the ball plunger arranged radially of the movable part, wherein the ball plunger includes an elastic body to provide a pre-tightening force between the movable part and the base, so that the The ball plunger cooperates with the bow spring body to form a balance, and the balance achieves the radial movement and can be restored.

In addition, there are 3 screw holes equiangularly distributed on the lower end surface of the lens holder 23 for placing three ball plungers 5 axially, and the other end of the ball plunger 5 is in contact with the end surface of the main lens barrel. The pretightening force and extension length of the three ball plungers 5 can be adjusted, so as to adjust the air gap and inclination of the movable mirror group 2 relative to the mirror group 3 . Sufficient pretightening force in the ball plunger 5 can support the movable mirror group 2 and ensure that the optical axis of the movable mirror group 2 does not tilt when the movable mirror group 2 moves radially.

As shown in FIG. 2 , the radial drive mechanism 8 is driven by the drive motor 6 . The driving motor 6 is fixed on the outside of the main lens barrel 1 along with the driving mechanism 8 through the motor fixing plate.

The structure of the radial adjustment device according to the invention has the following advantages.

(1) The radial adjustment device of the present invention includes a bow spring body and a ball plunger, and the bow spring body and the ball plunger cooperate to form a balance. Therefore, radial movement and recovery can be performed by utilizing the elasticity of the bow-shaped spring body and the ball plunger, and the structure is simple.

(2) The radial adjustment device of the present invention is driven by a motor, and has high precision.

A first example of the radial adjustment device of the present invention will now be described with reference to FIG. 4 .

As shown in FIG. 4 , the movable mirror group 2 moves radially under the action of the driving motor 6 . Two radial driving mechanisms 8 are installed in the main lens barrel 1 to form a 120-degree distribution. At a position of 120 degrees to the two driving mechanisms, a ball plunger 5 is placed in the main lens barrel 1, which provides resilience . The ball plunger 5 maintains a certain pretightening force during installation, so that two bow-shaped spring bodies and a ball plunger form a force balance in the horizontal plane. When the motor 6 drives a bow-shaped spring body to expand and contract, this balance mechanism can make the mirror base 23 move radially and return. The movement precision of the movable mirror group 2 depends on the precision of the motor and the precision of the radial driving mechanism 8, and the radial driving mechanism 8 can set a certain axial-radial conversion ratio. For example, if the axial-radial conversion ratio of the bow-shaped spring body is set to 5:1 in this device, every time the motor moves 5 mm in the axial direction, the movable lens will be pushed to move 1 mm in the horizontal direction. The device can provide a higher displacement precision of the movable mirror group 2, which can reach about 0.5um, and the stroke can reach ±0.5mm.

In the actual movement process, it is necessary to give the movable mirror group 2 an accurate X-direction movement amount and Y-direction movement amount. As shown in FIG. 4 , given that the direction where the ball plunger 5 is located is the +Y direction, the two radial driving mechanisms 8 respectively form an angle of 60 degrees with the Y axis. When the two driving mechanisms extend or contract at the same time, and the moving amounts are equal, the movable mirror group 2 will translate in the Y direction. When one of the two driving mechanisms stretches out and the other shrinks, and the moving amount is equal, the movable mirror group 2 will translate in the X direction. In other cases, the movement of the movable mirror base will have components in both X and Y directions.

Therefore, the optical element radial adjustment device in this embodiment is for adjusting the central position of the optical axis of the movable mirror group 2 relative to the system optical axis and the spatial position of the movable mirror group 2 relative to the fixed mirror group 3 .

The first example has the following advantages.

(3) Through the radial adjustment device including two bow-shaped spring bodies and a ball plunger, the movement in the X direction, the Y direction or the XY direction can be carried out, and the precision and flexibility are high.

A second example of the radial adjustment device of the present invention will now be described with reference to FIG. 5 .

The structure of this example is similar to that of the first example, and the same radial drive mechanism 8 is still used, the difference lies in the distribution of the drive mechanism 8 and the ball plunger 5 on the lens barrel 1 . Its distribution is shown in Figure 5. Two radial driving mechanisms 8 are installed in the main lens barrel 1 and distributed at 90 degrees, respectively along the +X and -Y directions; at positions 90 degrees from the two driving mechanisms, along the -X and +Y directions, in Two ball plungers 5 are placed in the main lens barrel 1, which provide resilience.

The ball plunger 5 maintains a certain preload during installation, so that the two bow-shaped spring bodies and the two ball plungers form a force balance in the horizontal plane. When the motor 6 drives a bow-shaped spring body to expand and contract, this balance mechanism can make the mirror base 10 move radially and return.

This embodiment can provide the same displacement accuracy and stroke of the movable mirror group 2 as the first embodiment.

The first example has the following advantages.

(4) The advantage of the arrangement of the driving mechanism and the ball plunger in this embodiment is that the driving directions of the two driving mechanisms are along the X axis and the Y axis respectively, and are orthogonal to each other. Therefore, the movable mirror group 2 does not interfere with each other when translating in the X direction and in the Y direction. When the driving mechanism in the X direction extends or contracts, the movable mirror group 2 only translates in the X direction; similarly, when the driving mechanism in the Y direction extends or contracts, the movable mirror group 2 only translates in the Y direction. When the two drive mechanisms work simultaneously, the movable mirror group 2 will simultaneously translate in both X and Y directions.

In another embodiment, the radial adjustment device in the above two embodiments may further include an axial drive mechanism 9 . As shown in FIG. 2 , both the radial driving mechanism 8 and the axial driving mechanism 9 are driven by a driving motor 6 . The driving motor 6 is fixed on the outside of the main barrel 1 along with the driving mechanisms 8 and 9 through the motor fixing plate. Three axial drive mechanisms 9 are uniformly fixed on the main lens barrel 1 along the optical axis direction by screws. The drive mechanism 9 used in the present invention is a common axial drive mechanism, which will not be described in detail here. Its stroke is ±0.5mm, and the adjustment accuracy is 0.5um.

The drive mechanism 9 means comprises at least three axial ball plungers 5'. The structure of the axial ball plunger 5' is identical to that of the ball plunger 5, and is also a set screw with a built-in compression spring. The difference is that the axial ball plunger 5' is arranged between the movable mirror group 2 and the main lens barrel 1 along the axial direction of the movable mirror group 2. Specifically, the axial ball plunger 5' is placed in the threaded hole on the lower end surface of the movable mirror base 23, so that one end is connected with the movable mirror base 23. The lower ball at the other end of the axial ball plunger 5' is in contact with the main lens barrel 1. When the axial ball plunger 5' is installed, a certain pretightening force is guaranteed, and the pretightening force depends on the compression distance of the inner spring of the axial ball plunger 5' and the stiffness K of the inner spring.

In this way, the radial adjustment device of this embodiment includes at least four ball plungers. Three of them are placed in the screw holes below the movable mirror base 23 and are evenly distributed in the axial direction to support the movable mirror group 2 . The pretightening force and extension length of the three ball plungers can be adjusted, so as to adjust the air gap between the movable mirror group 2 and the mirror group 3 .

Thus, the axial ball plunger 5' arranged in the axial direction of the movable part comprises an elastomer to provide a preload between the movable part and the base, so that a sufficient preload can Support the movable mirror group 2, and ensure that the optical axis of the movable mirror group lens 2 does not tilt when the movable mirror group 2 moves up and down.

In addition, the movable mirror group 2 can move in the horizontal direction under the action of the radial drive mechanism, and can also move up and down along the optical axis direction under the action of the axial drive mechanism.

The description and application of the invention herein is illustrative and is not intended to limit the scope of the invention to the above-described embodiments. Variations and changes to the embodiments disclosed herein are possible, and substitutions and equivalents for various components of the embodiments are known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be realized in other forms, structures, arrangements, proportions, and with other elements, materials and components without departing from the spirit or essential characteristics of the present invention. Other modifications and changes may be made to the embodiments disclosed herein without departing from the scope and spirit of the invention.

Claims (9)

1. radiai adjustment device that is used for optical system; Said optical system comprises base portion and movable member; Said radiai adjustment device is provided with between said base portion and the said movable member so that said movable member radially moves with respect to said base portion; It is characterized in that said radiai adjustment device comprises:

Radial drive mechanism; Comprise bow spring body and the drive motor that drives said bow spring body; One end of wherein said bow spring body is through being fixed on the said base portion; The other end contacts with said movable member, and the bow of said bow spring body go out the part the centre position directly contact with the push rod of said drive motor; And wherein when the push rod of said drive motor advances; The middle part of said bow spring body receives thrust and deforms; Its end that is connected with said movable member stretches out forward to form a tension force radially, moves radially thereby promote said movable member;

The bulb plunger that radially is provided with along said movable member; The one of which end is fixed on the periphery on the said base portion; The other end contacts with said movable member; Wherein said bulb plunger comprises elastic body so that the pretightning force between said movable member and the said base portion to be provided, thereby said bulb plunger cooperates with said bow spring body and forms balance, and said balance is reached and saidly moved radially and can reply.

2. radiai adjustment device as claimed in claim 1 is characterized in that, an end of said bow spring body is fixed on the said base portion through pin, and the other end directly contacts with said movable member.

3. radiai adjustment device as claimed in claim 1 is characterized in that, axially-radially conversion of said bow spring body is than being made as 5: 1.

4. radiai adjustment device as claimed in claim 1 is characterized in that, said bulb plunger is the holding screw of built-in compression spring.

5. radiai adjustment device as claimed in claim 4 is characterized in that, said pretightning force depends on the distance and the rigidity of said built-in compression spring compression.

6. like each described radiai adjustment device of aforementioned claim, it is characterized in that said movable member is a circular eyeglass, and said radiai adjustment device comprises two radial drive mechanism and a bulb plunger of 120 degree distributions at interval.

7. like each described radiai adjustment device among the aforementioned claim 1-5, it is characterized in that said movable member is a circular eyeglass, and said radiai adjustment device comprises two radial drive mechanism and two bulb plungers of 90 degree distributions at interval.

8. radiai adjustment device as claimed in claim 1; It is characterized in that; Also comprise the axial bulb plunger that makes the axially movable axial actuating mechanism of said movable member, said axial actuating mechanism comprise the axial setting of three said movable members in edge, and receive the driving of said drive motor.

9. radiai adjustment device as claimed in claim 8 is characterized in that an end of said axial bulb plunger is located at the lower surface of said movable member, and the other end contacts with said base portion.

Images