Focusing device

Abstract

A focusing device comprises a first prism and a second prism which are oppositely arranged, the first prism is installed on an installation seat through a fixing mechanism, the installation seat comprises a bearing seat and a T-shaped groove, the bearing seat comprises a protruding part for supporting the first prism, the protruding part is provided with an installation hole, and the T-shaped groove is provided with a T-shaped groove. The first prism comprises a wedge-shaped main body and lug parts located on the two sides of the wedge-shaped main body, the first prism is arranged in the T-shaped groove, the lug parts are attached to the protruding part through the fixing mechanism, the fixing mechanism comprises a first magnetic part and a second magnetic part, the first magnetic part is installed in the containing opening of the lug part, and the second magnetic part is installed in the containing opening of the lug part. The second magnetic piece is arranged in the mounting hole of the protruding part and is fixed through mutual attraction force with the first magnetic piece; and the second prism is arranged on the fixed seat. The influence of irregular expansion caused by glue solidification is avoided, and the installation precision is high.

Description

Technical Field

[0001] The invention relates to a focusing device, in particular to a focusing device applied to the field of laser direct writing. Background Art

[0002] The existing laser direct writing imaging exposure system, especially for high-precision lithography lenses, has a small focal depth, and the flatness of the substrate cannot meet the conditions of high-precision lithography, and the focal plane needs to be calibrated by focusing the lens.

[0003] The existing lens focusing method is to set a focusing device under the lens, use two upper and lower wedge prisms to form a parallel plate, and change the total thickness (Z direction) of the upper and lower wedge prisms corresponding to the same plane position by moving one of the wedge prisms to the left and right relative to the other wedge prism, or change the total thickness (Z direction) of the upper and lower wedge prisms corresponding to the same plane position by moving both wedge prisms to the left and right. The wedge prism in the focusing device is fixed by bonding. As the glue solidifies, irregular expansion will occur between the wedge prism and the bonded second moving part, and the original installation accuracy will be lost. In addition, the wedge prism and the second moving part are directly fixed by screws, which affects the surface shape of the wedge prism and cannot adjust the final accuracy. If the wedge prism is connected to the pressure plate by screws to press the prism, although the accuracy can be guaranteed at the beginning of installation, the pressure plate and the prism joint surface are prone to loosening during the high-speed movement of the focusing device, and the installation accuracy cannot be guaranteed for a long time. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a focusing device with high installation accuracy.

[0005] In order to solve the above problems, the present invention provides a focusing device, which includes a first prism and a second prism arranged opposite to each other, characterized in that: the first prism is installed on a mounting seat through a fixing mechanism, the mounting seat includes a bearing seat and a T-slot, the bearing seat includes a protruding portion supporting the first prism, the protruding portion is provided with a mounting hole, the first prism includes a wedge-shaped body and ears located on both sides of the wedge-shaped body, the first prism is placed in the T-slot, the ears are attached to the protruding portion through the fixing mechanism, the fixing mechanism includes a first magnetic member and a second magnetic member, the first magnetic member is installed in the receiving opening of the ear, the second magnetic member is placed in the mounting hole of the protruding portion, and is fixed by mutual attraction with the first magnetic member; the second prism is installed on the fixing seat.

[0006] Optionally, there is a gap between the first magnetic member and the second magnetic member.

[0007] Optionally, the spacing distance between the first magnetic member and the second magnetic member is set according to the magnetic moments of the first magnetic member and the second magnetic member, the mass of the first prism, the maximum acceleration of the first prism movement, and the allowable stress of the first prism.

[0008] Optionally, the spacing distance between the first magnetic member and the second magnetic member ranges from 0.36 mm to 0.52 mm.

[0009] Optionally, a size of the first magnetic member is not greater than a size of the accommodating opening, and a plane of the cap portion of the first magnetic member close to the protruding portion does not exceed a plane of the first prism close to the protruding portion.

[0010] Optionally, the first magnetic member is bonded to the receiving opening.

[0011] Optionally, the fixing seat includes a mounting groove and a mounting piece, the mounting piece is a hollow frame, the second prism is mounted on the mounting piece, and an adjustment mechanism is provided between the mounting piece and the mounting groove.

[0012] Optionally, the adjustment mechanism comprises flexible adjustment members that are arranged opposite to each other, the flexible adjustment members are located on two opposite sides of the mounting member, and two flexible adjustment members are arranged at intervals on the same side of the mounting member.

[0013] Optionally, the flexible adjusting member includes a flexible spring and an adjusting top screw, two ends of the flexible spring are respectively fixed to the mounting member and the mounting groove, and the adjusting top screw abuts against the flexible spring.

[0014] Optionally, the flexible spring sheet rigidly supports the mounting member and the mounting groove, and flexibly adjusts the mounting member.

[0015] Optionally, the external dimensions of the flexible portion of the flexible spring are analyzed by slice element method to determine whether the vertical stiffness of the flexible spring meets the requirements.

[0016] Optionally, the vertical stiffness is the moment M of the microelement of the flexible spring around the Rx direction. t Deformation angle a with respect to the flexible spring Rx direction t The ratio of the vertical stiffness of the flexible reed is obtained based on the following formula:

[0017]

[0018] Among them, a t is the deformation angle of the flexible reed in the Rx direction, Mt is the moment of force on the microelement in the Rx direction, E is the elastic modulus of the material; C is the height of the microelement, t is the minimum thickness of the flexible reed, R is the cutting radius of the flexible reed, θ 1 The arc center angle at the microelement slice, θ2 It is the central angle of the end point of the arc of the flexible part of the flexible spring. It is used to determine whether the vertical stiffness design of the flexible part meets the requirements.

[0019] Optionally, the length L of the flexible part of the flexible spring is determined according to the cross-sectional area of ​​the flexible spring at the lowest vertical stiffness, and the calculation method is L=AE / K2, wherein A=t×b is the cross-sectional area of ​​the flexible part, E is the product of the material density and the corresponding empirical coefficient, which is a constant determined according to the material; K2 is the required horizontal stiffness requirement; horizontal stiffness Among them, M 2 is the overall mass of the mounting base 200 of the first moving part and the first prism, a is the maximum acceleration of the first moving part, and S is the variable gap of the prism.

[0020] Compared with the prior art, the technical solution of the present invention adopts magnetic attraction to fix, so that the ear of the first prism is attached to the protrusion of the supporting seat through magnetic adsorption. The installation accuracy of the first prism can be guaranteed by ensuring the processing accuracy of the ear of the first prism and the protrusion of the supporting seat. It is not affected by the installation accuracy of the first magnetic part and the second magnetic part, and the installation accuracy is more controllable. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is an overall schematic diagram of the focusing device.

[0022] Figure 2 This is a schematic diagram of the interior of the focusing device.

[0023] Figure 3 It is a schematic diagram of the movement device of the focusing device.

[0024] Figure 4 It is a disassembled schematic diagram of the moving device of the focusing device.

[0025] Figure 5 is a schematic diagram of a first prism and a first magnetic member.

[0026] Figure 6 is a schematic diagram of the first moving part.

[0027] Figure 7 yes Figure 3 Schematic diagram of the AA section.

[0028] Figure 8 It is a three-dimensional schematic diagram of the second moving part.

[0029] Fig. 9 It is a three-dimensional schematic diagram of the back side of the second moving part.

[0030] Fig.10 is a schematic diagram of a flexible reed.

[0031] Fig.11 It is a schematic diagram of a microelement.

[0032] Fig.12 is a side view of the flexible reed. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described below by means of specific embodiments shown in the accompanying drawings.

[0034] like Figure 1-Figure 12 As shown, the focusing device includes a shell 1 and a moving device 2, wherein the moving device 2 is installed in the shell 1, and the shell 1 is provided with a light hole 10 corresponding to the lens. A flexible limiting mechanism 11 is provided inside the shell 1 corresponding to the moving device 2 to avoid a hard collision between the moving device 2 and the shell 1 during movement.

[0035] The moving device 2 includes a first moving member 20 and a second moving member 21. The second moving member 21 and the first moving member 20 are connected via a guide rail 22. Preferably, the guide rail 22 is a cross roller guide rail.

[0036] The first moving member 20 includes a mounting seat 200, a first prism 201, a motion driving mechanism 202 and a fixing mechanism, wherein the motion driving mechanism is connected to the mounting seat 200, and drives the mounting seat 200 to drive the first prism 201 to move relative to the second moving member 21. The mounting seat 200 includes a bearing seat 2000 and a T-slot, wherein the bearing seat 2000 includes a protrusion 2001 corresponding to the T-slot, and the protrusion 2001 is provided with a mounting hole 2002. The first prism 201 includes a wedge-shaped body 2010 and ears 2011 located at both ends of the wedge-shaped body 2010. The ears 2011 are provided with a receiving opening 2012 on one side facing the protrusion 2001. The fixing mechanism includes two mutually adsorbed first magnetic members 2030 and second magnetic members 2040. The first magnetic member 2030 includes a cap 2031 and an extension 2032 connected to the cap. The cap 2031 of the first magnetic member is installed in the receiving opening 2012 and connected to the first prism 201. The extension 2032 of the first magnetic member 2030 extends into the mounting hole 2002. The size of the first magnetic member is not larger than the size of the receiving opening. The plane of the cap of the first magnetic member close to the protrusion 2001 does not exceed the plane of the first prism close to the protrusion 2001. The first magnetic member can be connected to the first prism by an adhesive. The second magnetic member 2040 has the same structure as the first magnetic member 2030. The second magnetic member 2040 is fixed to the other side of the mounting hole by the mutual attraction with the first magnetic member 2030. The extension of the second magnetic member 2040 extends into the mounting hole 2002, and the cap of the second magnetic member 2040 abuts against the protrusion 2001. Preferably, there is a gap between the first magnetic member 2030 and the second magnetic member 2040. The size of the gap is obtained according to the mass of the first prism 201, the maximum acceleration borne by the mounting seat 200 during the movement, the allowable stress of the material of the first prism 201, the area of ​​action of the mutual attraction between the first magnetic member 2030 and the second magnetic member 2040, and the magnetic moment of the first magnetic member 2030 and the second magnetic member 2040, so as to ensure that the first prism 201 does not move during the movement, and does not damage the first prism 201 whose material is fragile.

[0037] like Figure 1-Figure 10 As shown, the force F exerted on the first prism 201 during the acceleration motion 移 , the positive pressures (mutual attraction) of the first magnetic member 2030 and the second magnetic member 2040 on the first prism are F1, F2, F3 and F4 respectively. In order to prevent the first magnetic member 2030 and the second magnetic member 2040 from shifting, the sum of the positive pressures (F1+F2+F3+F4) of the first magnetic member 2030 and the second magnetic member 2040 on the first prism 201 is not less than the maximum force F1 applied to the first prism 201 during the accelerated motion.移 , the maximum force F exerted on the first prism 201 during the acceleration motion 移 The mass M passing through the first prism 201 1 The maximum force F exerted on the first prism 201 during the accelerated motion is obtained by multiplying the maximum acceleration a exerted on the first prism 201 during the accelerated motion. 移 The minimum value of the mutual attraction between the pair of first magnetic members 2030 and the second magnetic members 2040 can be obtained.

[0038] Since the material of the first prism 201 is usually relatively fragile, the mutual attraction between the first magnetic member 2030 and the second magnetic member 2040 is not necessarily greater, and in order to avoid damaging the first prism 201, according to the allowable stress σ of the first prism 201 s Determine the maximum value of the mutual attraction between the first magnetic component 2030 and the second magnetic component 2040 (obtained by querying the national standard table based on the material).

[0039] First, the stress σ generated by the total mutual attraction force (F1+F2+F3+F4) on the first prism 201 is obtained: 1-4 , stress σ 1-4 It is obtained by the ratio of the total mutual attraction force on the first prism 201 to the action area A of the total mutual attraction force on the first prism 201. In order to avoid damaging the first prism 201, the stress σ 1-4 The allowable stress σ of the first prism must not be greater than s , based on which the maximum value of the mutual attraction force between a pair of first magnetic members 2030 and the second magnetic members 2040 can be obtained.

[0040] By obtaining the maximum and minimum values ​​of the mutual attraction between the first magnetic member 2030 and the second magnetic member 2040, according to the relationship between the mutual attraction between the magnets and the distance F d =K×(m 1 ×m 2 ) / d 2 (where F d is the attraction between magnets; K is the magnet constant; m 1 Magnetic moment of the first magnetic member 2030; m 2 d is the magnetic moment of the second magnetic member 2040; d is the distance between the first magnetic member 2030 and the second magnetic member 2040), an appropriate range of the distance between the first magnetic member 2030 and the second magnetic member 2040 can be obtained. The distance between the first magnetic member 2030 and the second magnetic member 2040 is selected within the appropriate range of the distance between the first magnetic member 2030 and the second magnetic member 2040.

[0041] For the focusing device, the distance d between the first magnetic member 2030 and the second magnetic member 2040 is preferably set between 0.36 mm and 0.52 mm, which is suitable for the material of the conventional first prism 201 and the movement speed of the first moving member 20, while avoiding the first moving member 20 from being too large. The magnetic member can be made of neodymium iron boron magnet, aluminum nickel cobalt magnet, ferrite magnet, etc.

[0042] By means of magnetic attraction of the first magnetic member 2030 and the second magnetic member 2040, the ear 2011 of the first prism 201 is attached to the protrusion 2001 of the bearing seat 200, and the position of the first prism 201 is fixed, which is not affected by the installation accuracy of the first magnetic member 2030 and the second magnetic member 2040, and the installation accuracy is more controllable. At the same time, the spacing distance between the first magnetic member 2030 and the second magnetic member 2040 is convenient for controlling the mutual attraction between the first magnetic member 2030 and the second magnetic member 2040, which ensures that the first prism 201 does not move during the movement, and does not damage the first prism 201 of fragile material.

[0043] The second moving part 21 includes a fixed seat 210, a second prism 211 and an adjusting mechanism 212. The fixed seat 210 is installed on the housing 1. The second prism 211 and the adjusting mechanism 212 are installed on the fixed seat 210. The fixed seat 210 includes a mounting groove 2100 and a mounting member 2101. The mounting member 2101 is a hollow frame. The second prism 211 is installed on the mounting member 2101. The adjustment mechanism 212 includes relatively arranged flexible adjustment members, the flexible adjustment members are located at opposite sides of the mounting member 2101, two flexible adjustment members are spaced apart on the same side of the mounting member 2101, the flexible adjustment members include a flexible spring 2120 and an adjustment top screw 2121, the two ends of the flexible spring 2120 are respectively fixed to the mounting member 2101 and the mounting groove 2100, the adjustment top screw 2121 is installed on the support member 2102, fixed by the support member 2102, the top of the adjustment top screw 2121 abuts against the flexible spring 2120, and the support member 2102 is fixed to the mounting groove 2100 by a locking member (not shown) and a locking hole 2103. Preferably, the adjustment top screw 2121 abuts against the middle position of the flexible spring 2120, so as to facilitate the adjustment of the position of the second prism 211. By adjusting the adjusting screw 2121 to act on the flexible spring 2120 , the flexible spring 2120 is deformed by force, driving the mounting member 2101 to shift, thereby changing the relative position of the second prism 211 and the first prism 201 .

[0044] The flexible spring 2120 includes a flexible portion 2122 and fastening portions 2123 located at both ends of the flexible portion 2122. The fastening portion 2123 includes a fixed end portion 2124 connected to the flexible portion 2122 and a reinforcing portion 2125 located at both sides of the fixed end portion and protruding inward. The flexible spring 2120 is respectively connected to the mounting member 2101 and the mounting groove 2100 through the reinforcing portion 2125. The flexible portion 2122 is recessed from the fixed end portions 2124 at both sides to the middle. The thickness of the flexible portion 2122 is the largest at both ends and the smallest at the middle.

[0045] The flexible spring 2120 needs to ensure the rigidity of connecting the mounting member 2101 and the mounting groove 2100, so that the position of the second prism 211 will not be moved during the movement of the first moving member 20; at the same time, it has the flexibility to be deformed, which is convenient for adjusting the position of the second prism 211. In order to achieve the above effect, it is necessary to determine whether the vertical rigidity of the flexible spring 2120 meets the requirements. If it does not meet the requirements, adjust the specification parameters of the flexible spring to meet the requirements. If it meets the requirements, the horizontal rigidity of the flexible spring is obtained according to the gap change amount that the second prism 211 needs to meet the prism, and the length of the flexible spring is obtained according to the horizontal rigidity of the flexible spring. If the end width of the flexible part is a, the thickness is b, and the minimum thickness in the middle is t, the middle depression of the flexible part is an arc, and the cutting radius is R.

[0046] The vertical stiffness of the flexible spring 2120 can be at the lowest stiffness (thickness t position) arc center angle θ 1 The slice differential method is used to analyze the Fig.11 As shown, the height of the microelement is:

[0047] C=t+2R-2Rcosθ 1 The width of the microelement is:

[0048] du=d(Rsinθ 1 )=Rcosθ 1 dθ 1

[0049] From the micro-element point of view, the vertical force Ft can be converted into Mt around the X direction. Under the action of the micro-element moment Mt, the deformation angle da along the X direction is t It can be expressed as:

[0050]

[0051] Where E is the elastic modulus of the material; I t is the moment of inertia of the microelement interface along the X direction,

[0052] The infinitesimal deformation angle da will be obtained t Amplification by the integral theorem:

[0053]

[0054] The deformation of the entire flexible spring is obtained. The vertical stiffness K1 of the flexible spring is the moment M of the microelement of the flexible spring around the Rx direction. t Deformation angle a with respect to the flexible spring Rx direction t According to the required adjustment range of the second prism, it is determined whether the vertical stiffness K1 design of the flexible member meets the requirements.

[0055] After the vertical stiffness of the flexible spring sheet meets the requirement, the length L between the ends of the fastening portion in the flexible spring sheet is calculated so that the flexible spring sheet meets the horizontal stiffness requirement.

[0056] like Fig.12 As shown, the horizontal stiffness K2 is related to the overall mass M of the mounting base 200 of the first moving member and the first prism. 2 , the maximum acceleration a of the first moving part and the variable gap S of the prism. The variable gap S of the prism is the allowable error range of the gap between the first prism and the second prism set according to the optical requirements. The maximum and minimum values ​​of the error range are the maximum and minimum values ​​of the gap between the first prism and the second prism within the allowable error range. The specific calculation formula is:

[0057]

[0058] According to the relationship between the length and stiffness of the flexible part:

[0059] L=AE / K2 (2)

[0060] In the formula: A=t×b is the cross-sectional area of ​​the flexible part, E is the product of the material density and the corresponding empirical coefficient, which is a constant determined according to the material; L is the length of the flexible part.

[0061] The maximum acceleration a of the first moving part is determined according to the basic surface shape of the workpiece to be processed for which the focal plane adjustment is required. The range of the length L of the flexible part is determined according to the range of the variable gap amount of the prism. That is, the maximum value of the length L of the flexible part is obtained according to the maximum value of the variable gap amount of the prism, and the minimum value of the length L of the flexible part is obtained according to the minimum value of the variable gap amount of the prism.

[0062] The flexible spring 2120 is fixed to the mounting member 2101 by a fixing nut, and the mounting member 2101 has a notch for accommodating the fixing nut, so that the second prism 211 fits more closely to the mounting member 2101 and is fixed more firmly. Then, the second prism 211 and the mounting member 2101 are fixed by glue, and after the glue is completely cured, the position of the second prism 211 is adjusted.

[0063] When adjusting the relative position of the second prism 211 and the first prism 201, the position of the second prism 211 is adjusted by four flexible adjustment members located at both ends of the second prism 211, and the adjustment screws of different flexible adjustment members are adjusted to enable the second prism to achieve six degrees of freedom adjustment in the X direction, Y direction, Z direction and rotation in all directions.

[0064] The position of the second prism 211 is adjusted by the top screw 2121 acting on the flexible spring 2120 , and the adjustment accuracy is higher through the deformation adjustment of the flexible spring 2120 .

[0065] The first moving part of the focusing device is fixed by magnetic attraction, and the ear of the first prism is attached to the protrusion of the support seat by magnetic attraction. The installation accuracy of the first prism can be guaranteed by ensuring the processing accuracy of the ear of the first prism and the protrusion of the support seat, which is not affected by the installation accuracy of the first magnetic part and the second magnetic part, and the installation accuracy is more controllable. At the same time, after the glue is cured, the relative position of the second prism and the first prism is adjusted by the adjustment mechanism, so that the gap between the second prism and the first prism has higher installation accuracy, is not affected by the irregular expansion of the glue curing, and is easy to adjust.

Claims

1. A focusing device, comprising a first prism and a second prism arranged opposite to each other, characterized in that: The first prism is mounted on the mounting seat through a fixing mechanism, and the mounting seat includes a bearing seat and a T-slot, the bearing seat includes a protruding portion supporting the first prism, and the protruding portion is provided with a mounting hole, the first prism includes a wedge-shaped body and ears located on both sides of the wedge-shaped body, the first prism is placed in the T-slot, and the ears are attached to the protruding portion through the fixing mechanism, the fixing mechanism includes a first magnetic component and a second magnetic component, the first magnetic component is installed in the receiving opening of the ear, and the second magnetic component is placed in the mounting hole of the protruding portion and is fixed by mutual attraction with the first magnetic component; the second prism is mounted on the fixing seat.

2. The focusing device according to claim 1, characterized in that: There is a gap between the first magnetic member and the second magnetic member.

3. The focusing device according to claim 1, characterized in that: The spacing distance between the first magnetic member and the second magnetic member is set according to the magnetic moments of the first magnetic member and the second magnetic member, the mass of the first prism, the maximum acceleration of the first prism movement, and the allowable stress of the first prism.

4. The focusing device according to claim 2, characterized in that: The spacing distance between the first magnetic component and the second magnetic component ranges from 0.36 mm to 0.52 mm.

5. The focusing device according to claim 1, characterized in that: The size of the first magnetic member is not greater than the size of the accommodating opening, and the plane of the cap portion of the first magnetic member close to the protruding portion does not exceed the plane of the first prism close to the protruding portion.

6. The focusing device according to claim 1, characterized in that: The first magnetic member is bonded to the receiving opening.

7. The focusing device according to claim 1, characterized in that: The fixing seat comprises a mounting groove and a mounting member, the mounting member is a hollow frame, the second prism is mounted on the mounting member, and an adjustment mechanism is arranged between the mounting member and the mounting groove.

8. The focusing device according to claim 7, characterized in that: The adjustment mechanism comprises flexible adjustment members arranged opposite to each other, the flexible adjustment members are located on two opposite sides of the mounting member, and two flexible adjustment members are arranged at intervals on the same side of the mounting member.

9. The focusing device according to claim 8, characterized in that: The flexible adjusting member comprises a flexible spring and an adjusting top screw. Two ends of the flexible spring are respectively fixed to the mounting member and the mounting groove, and the adjusting top screw abuts against the flexible spring.

10. The focusing device according to claim 9, characterized in that: The flexible spring sheet rigidly supports the mounting member and the mounting groove and flexibly adjusts the mounting member.

11. The focusing device according to claim 8, characterized in that: The external dimensions of the flexible portion of the flexible spring are analyzed by slice microelement method to determine whether the vertical stiffness of the flexible spring meets the requirements.

12. The focusing device according to claim 11, characterized in that: The vertical stiffness is the moment M of the microelement of the flexible spring around the Rx direction. t Deformation angle a with the flexible spring Rx direction t The ratio of the vertical stiffness of the flexible reed is obtained based on the following formula: Among them, a t is the deformation angle of the flexible spring in the Rx direction, Mt is the moment about the microelement in the Rx direction, E is the elastic modulus of the material; C is the height of the microelement, t is the minimum thickness of the flexible spring, R is the cutting radius of the flexible spring, θ1 is the center angle of the arc at the microelement slice, and θ2 is the center angle of the end point of the arc of the flexible part of the flexible spring; judge whether the vertical stiffness design of the flexible part meets the requirements.

13. The focusing device according to claim 12, characterized in that: The length L of the flexible part of the flexible spring is determined according to the cross-sectional area at the lowest vertical stiffness of the flexible spring, and the calculation method is L=AE / K2, Among them, A = t × b is the cross-sectional area of ​​the flexible part, E is the product of the material density and the corresponding empirical coefficient, which is a constant determined according to the material; K2 is the required horizontal stiffness requirement; Horizontal stiffness Wherein, M2 is the overall mass of the mounting base 200 of the first moving part and the first prism, a is the maximum acceleration of the first moving part, and S is the variable gap amount of the prism.

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