A rotation adjustment device for interferometer measurement of spherical lens surface error

Abstract

The utility model discloses a kind of rotary adjusting devices for interferometer measurement spherical surface lens surface shape error, be arranged in the measuring area of interferometer, including cylindrical jig, T jig, cylindrical jig upper end is along central axis direction, be equipped with the first groove and the second groove of cross, T jig upper end places lens to be measured, T jig lower part is adjustably fixed in the second groove by screw rod, so that T jig is suspended in the first groove, and T jig can rotate around screw rod central axis under the driving of screw rod. The device can be used with existing interferometer, by adjusting the angle and position of lens, effectively expand the measurement range of interferometer, realize the edge interference measurement of spherical surface lens surface shape, solve the problem that lens edge cannot be effectively measured due to the limitation of interference measurement range, and it is suitable for the measurement of spherical surface lens of multiple sizes and curvatures.

Description

Technical Field

[0001] This utility model relates to optical lens testing technology, and in particular to a rotation adjustment device for measuring the surface shape error of a spherical lens using an interferometer. Background Technology

[0002] In the cold processing of optical lenses, the surface accuracy of spherical lenses is typically measured using an interferometer to comprehensively inspect their curvature. Specifically, the surface accuracy is determined by the interference pattern formed on the interferometer screen. However, this method has limitations. For example, if the interferometer lens specifications do not match the lens size, the lens's measurement range is limited, often failing to cover the entire curvature, resulting in a measurement blind spot at the lens edges. In such cases, the surface accuracy at the lens edges can only be estimated, leading to a significant error in determining the overall surface accuracy. Utility Model Content

[0003] Purpose of the utility model: The purpose of this utility model is to provide a rotation adjustment device for measuring the surface shape error of a spherical lens using an interferometer. It is used in conjunction with an existing interferometer to achieve interferometric measurement of the surface shape edge of a spherical lens.

[0004] Technical Solution: To achieve the above objectives, the present invention provides a rotary adjustment device for measuring the surface shape error of a spherical lens using an interferometer. The device is set within the measurement area of ​​the interferometer and includes a cylindrical fixture and a T-shaped fixture. The upper end of the cylindrical fixture has a first groove and a second groove that intersect in a cross shape along the central axis. The upper end of the T-shaped fixture holds the lens to be measured, and the lower part is adjustablely fixed in the second groove by a screw, so that the T-shaped fixture is suspended in the first groove and rotates around the central axis of the screw under the drive of the screw.

[0005] Preferably, it also includes a base for fixing the cylindrical fixture to the interferometer measurement area.

[0006] Preferably, both the first groove and the second groove penetrate the wall of the cylindrical fixture in the radial direction.

[0007] Preferably, the depth difference between the first groove and the second groove is greater than the distance from the central axis of the screw to the bottom of the cylindrical fixture.

[0008] Preferably, the lower part of the T-shaped fixture is a hollow structure, and a third groove is provided along the central axis. The third groove penetrates the wall of the T-shaped fixture in the radial direction, and the middle section of the screw is symmetrically fixed in the third groove.

[0009] Preferably, a first axial scale is provided on one side of the third groove.

[0010] Preferably, a second axial scale is provided on one side of the second groove, and an angle scale line is provided on the side end face of the screw.

[0011] Beneficial effects: This utility model has the following advantages: 1. This device can be used in conjunction with existing interferometers. By adjusting the angle and position of the lens, the measurement range of the interferometer can be effectively expanded, realizing the interference measurement of the surface edge of the spherical lens, and solving the problem that the lens edge cannot be effectively measured due to the limitation of the interference measurement range; 2. It has a simple structure, is easy to operate, and has low cost. It is also suitable for measuring spherical lenses of various sizes and curvatures, and has good versatility and adaptability. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this device. Detailed Implementation

[0013] The technical solution of this utility model will be described in detail below with reference to the embodiments and accompanying drawings.

[0014] like Figure 1 As shown, the rotation adjustment device of this utility model is suitable for use on a vertical measurement interferometer, and includes: a base 1, a cylindrical fixture 2, a screw 3, an outer nut 4, an inner nut 5, and a T-shaped fixture 6. Figure 1 It also includes the lens to be measured 7, the interferometer lens 8, and the interferometer screen 9.

[0015] The base 1 is used to fix the cylindrical fixture 2 within the measurement area of ​​the interferometer. The base 1 can be the base of the interferometer body, or it can serve as a connector between the cylindrical fixture 2 and the existing base of the interferometer, providing support and fixation. The center of the base 1 has a groove for tight fitting with the lower end of the cylindrical fixture 2.

[0016] The upper center of the cylindrical fixture 2 has two sets of grooves along the central axis, namely the first groove and the second groove. The first groove is deeper and wider than the second groove. Both grooves penetrate the cylindrical fixture 2 in the transverse (radial) direction, forming a cross-shaped structure. As shown in the figure, the first groove divides the upper half of the cylindrical fixture 2 into two independent structures, and the second groove further divides these two structures into two parts.

[0017] The T-shaped fixture 6 is suspended within the groove of the cylindrical fixture 2 by a screw 3, and the screw 3 acts as a pivot point, enabling the T-shaped fixture 6 to swing within the groove. The upper platform of the T-shaped fixture 6 is used to place the lens 7 to be measured. To facilitate the placement of the lens 7, a groove of a certain depth matching the depth of the lens 7 is provided on the platform (the depth of the groove is less than the edge thickness of the lens 7). The lower half of the T-shaped fixture 6 is a hollow structure, and this area has a third groove that passes through the central axis and extends laterally.

[0018] The screw 3 is symmetrically fixed in the third groove using the inner nut 5, and the central axis of the screw 3 intersects perpendicularly with the central axis of the fixture 6. The screw 3 can move within the third groove. To determine the vertical distance between the screw 3 and the bottom of the upper groove of the T-shaped fixture 6, a first axial scale is provided near the third groove. The value of the starting point of the first axial scale is the vertical distance between that point and the bottom of the upper groove of the T-shaped fixture 6. At the same time, a reference line is provided on the screw 3, which is aligned with the first axial scale, to read the displacement of the screw 3 in the vertical direction, thereby determining its vertical distance from the bottom of the upper groove of the T-shaped fixture 6.

[0019] The screw section of the screw 3, located outside the inner nut 5, is symmetrically installed in the second groove of the cylindrical fixture 2, and can move up and down and rotate along the groove for position adjustment. After the screw 3 is adjusted to the appropriate position, it is fixed in the second groove by the outer nut 4, which is located outside the cylindrical fixture 2 to limit the movement of the screw 3 and ensure the stability of the screw 3's position after adjustment.

[0020] To determine the position of the screw 3 on the cylindrical fixture 2, a second axial scale is provided on the outer side of the cylindrical fixture 2, near the second groove. Simultaneously, rotation angle scale lines are evenly distributed around the center point of the screw on the side end face of the screw 3. The transverse scale lines on the second axial scale can serve as reference lines for the rotation scale lines (the scale lines at the corresponding positions are selected based on the specific position of the screw 3), thereby obtaining the rotation angle of the screw 3 driving the T-shaped fixture 6.

[0021] The depth difference between the first groove and the second groove is greater than the distance from the central axis of the screw 3 to the bottom of the cylindrical fixture 2, and the cylindrical fixture does not touch the bottom of the first groove during rotation.

[0022] The initial state of the device placed in the interferometer measurement area is that the T-shaped fixture 6 and the cylindrical fixture 2 are coaxial, the lens to be measured 7 is located in the groove at the upper end of the T-shaped fixture 6, and the vertical distance from the center of curvature of the upper surface of the lens to be measured 7 to the central axis of the screw 3 (obtained by the first axial scale) is the same as the curvature of the upper surface of the lens to be measured 7.

[0023] Adjust the positions of the interferometer lens 8 and the base 1 in a coordinated manner until clear interference fringes appear on the interferometer screen 9. Based on the size of the lens 7 under test, the diameter of the area of ​​the lens 7 that the interferometer lens 8 can currently measure, and the distance between the lens 8 and the lens 7 under test, calculate the angle at which the interferometer lens 8 should be deflected to measure the outermost edge of the lens 7 under test.

[0024] Rotate screw 3 according to the deflection angle, thereby rotating T-shaped fixture 6 into the measurable area of ​​interferometer lens 8. Fine-tune interferometer lens 8 and base 1 until clear interference fringes appear on interferometer screen 9. At this time, the lens under test 7 can be rotated on T-shaped fixture 6 to achieve edge interference measurement of lens under test 7.

Claims

1. A rotation adjustment device for measuring the surface shape error of a spherical lens using an interferometer, disposed within the measurement area of ​​the interferometer, characterized in that, It includes a cylindrical fixture (2) and a T-shaped fixture (6). The upper end of the cylindrical fixture (2) is provided with a first groove and a second groove that intersect in a cross shape along the central axis. The upper end of the T-shaped fixture (6) is used to place the lens (7) to be measured, and the lower part is adjustablely fixed in the second groove by a screw (3), so that the T-shaped fixture (6) is suspended in the first groove and rotates around the central axis of the screw (3) under the drive of the screw (3).

2. The rotary adjustment device according to claim 1, characterized in that, It also includes a base (1) for fixing a cylindrical fixture (2) to the measurement area of ​​the interferometer.

3. The rotary adjustment device according to claim 1, characterized in that, The first and second grooves both penetrate the wall of the cylindrical fixture (2) in the radial direction.

4. The rotary adjustment device according to claim 1, characterized in that, The depth difference between the first groove and the second groove is greater than the distance from the central axis of the screw (3) to the bottom of the cylindrical fixture (2).

5. The rotary adjustment device according to claim 1, characterized in that, The lower part of the T-shaped fixture (6) is hollow and has a third groove along the central axis. The third groove penetrates the wall of the T-shaped fixture (6) in the radial direction, and the middle section of the screw (3) is symmetrically fixed in the third groove.

6. The rotary adjustment device according to claim 5, characterized in that, A first axial scale is provided on one side of the third groove.

7. The rotary adjustment device according to claim 1, characterized in that, A second axial scale is provided on one side of the second groove, and an angle scale line is provided on the side end face of the screw (3).

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