Holding device and holding method for holding optical element for inspection

Abstract

To provide a holding device and a holding method for holding an optical element for testing.SOLUTION: A holding device (100) for holding an optical element (OE) for testing comprises a hollow base body (110), a stationary ring (120), and a movable ring (130). The stationary ring (120) is arranged on or fastened to the base body (110), and has, at one axial end, a contact face (122) for bearing against the optical element (OE). The movable ring (130) is supported axially displaceably on the base body (110) relative to the stationary ring (120) and the base body (110), and has, at one axial end, a contact face (132) for bearing against the optical element (OE). The stationary ring (120) and the movable ring (130) are arranged coaxially with respect to one another, where a gap (140) is arranged at least between the stationary ring (120) and the movable ring (130) and allows generation of a vacuum for holding the optical element (OE).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The invention is based on an apparatus or a method according to the preambles of the independent claims. [Background technology]

[0002] Measurement of the optical element or test piece under test using conventional vacuum holding devices can be performed on only one side or through a glass window. Alternatively, the test piece can be mechanically gripped at its periphery in a conventional manner.

[0003] Patent document 1 describes a windowless device for holding a lens using a vacuum during a bonding process, where the lens holding device comprises an outer region and an inner region, which are flexibly and firmly connected to each other via bearings. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2014-000621A Summary of the Invention [Means for solving the problem]

[0005] Against this background, the approach presented herein provides, according to the main claims, an improved holding device for holding an optical element for inspection and an improved method for holding an optical element for inspection. The measures recited in the dependent claims allow advantageous developments and improvements to the devices recited in the independent claims.

[0006] The above approach makes it possible in particular to hold the optical element under test securely during the test, i.e. during the measurement and alignment process, for example, to avoid the test being influenced by the holding device, and in particular to provide a universally applicable holding device that can hold optical elements of various geometric shapes.

[0007] A holding device for holding an optical element for inspection, the holding device comprising: a hollow base; a fixed ring arranged or fixed to the base and having a contact surface at one axial end for abutting against the optical element; and a movable ring supported on the base so as to be axially displaceable relative to the fixed ring and the base, the movable ring having a contact surface at one axial end for abutting against the optical element, the fixed ring and the movable ring being arranged coaxially with each other, and a gap capable of generating a vacuum for holding the optical element being arranged at least between the fixed ring and the movable ring.

[0008] The optical element may be, for example, a lens. The base may be attachable or attached to the actuator. The fixing ring and the base may be made as separate parts or as an integral part. If the fixing ring is disposed on the base, the fixing ring and the base may be made as one part or as an integral part. Furthermore, the base may have a rotationally symmetric or rotationally asymmetric geometric shape depending on the type of optical element to be held. If the optical element to be held is spherical or aspherical, a cylindrical base may be used. The fixing ring may be hollow cylindrical. The movable ring may be hollow cylindrical. In this case, the ring may also be referred to as a ring part, ring element, or ring unit.

[0009] According to one embodiment, the mobile ring can be arranged radially inside or outside the fixed ring, in this way protection of the mobile ring and its receiving structure can be ensured.

[0010] Furthermore, a through-opening can be formed in the movable or fixed ring, passing axially through the entire movable ring. The through-opening can also be referred to as an aperture. This allows for the omission of a window, thereby preventing the holding device from affecting the inspection or measurement. Otherwise, measurements through a glass window can be erroneous, since the glass window can have a variable effect on the measurement result that is not easily quantifiable.

[0011] In particular, the contact surface of the ring can be formed as a cutting edge. Additionally or alternatively, the contact surface can be formed so as to abut against the optical element along a concentric circle. In order to hold rotationally asymmetric test pieces as well, other concentric geometric shapes, such as, for example, a cylinder, are also conceivable in this case. To this end, a holding device can be provided in the form of a vacuum double ring cutting edge, which can reliably fix the optical element (also referred to as test piece) during the measurement and alignment process. Furthermore, the vacuum double ring cutting edge can be universally adapted to the geometries of several test pieces in one assembly process.

[0012] The holding device may have a biasing device for biasing the movable ring away from the base, which may in particular comprise elastic or pneumatic means, so that the movable ring can be reliably abutted against the optical element independently of the orientation of the holding device relative to the Earth's gravitational field.

[0013] According to one embodiment, the base may have guide portions formed to guide the movement of the movable ring relative to the base and the fixed ring, In this way, the movable ring can be guided accurately and reliably to adapt to the geometry of the optical element.

[0014] In this case, a fitting, in particular a loose fitting, between the guide part of the base body and the guided part of the movable ring can be configured as a sliding guide.

[0015] Additionally or alternatively, the holding device can comprise guide means provided on the base body, which are configured to guide the movement of the movable ring relative to the base body and the fixed ring. In this case, in particular, the guide means can comprise a membrane guide. In this way too, precise movement guidance can be achieved while simultaneously providing a seal for applying a vacuum.

[0016] Furthermore, the base body can have at least one stop portion configured to limit the movement of the movable ring relative to the base body and the fixed ring. In particular, the movable ring can be held securely on the base body in this way without falling off. Furthermore, the stroke of movement can be precisely defined.

[0017] The movable ring can also be provided with shoulders that limit its movement relative to the base and the fixed ring. This method also allows for a precise definition of the stroke of movement. Furthermore, a reliable hold of the movable ring relative to the base can be achieved.

[0018] According to one embodiment, the movable ring can be formed in one piece. Such an embodiment offers the advantage that the number of individual parts of the holding device can be reduced. In particular, the movable ring can be made particularly robust in this way.

[0019] Alternatively, the movable ring can be made of multiple parts. In this case, the contact surface can be arranged on a first part of the movable ring. The guided part, which is guided through the base body, can be arranged on a second part of the movable ring. In this case, the first and second parts of the movable ring can be connected to each other. The first and second parts can be frictionally connected to each other, or additionally or alternatively, can be positively connected to each other. The first and second parts can be directly connected to each other or can be connected via at least one intermediate part.

[0020] A method for holding an optical element for inspection includes positioning the holding device so that the contact surface abuts the optical element, and creating a vacuum in the gap to hold the optical element.

[0021] The positioning and generating steps can advantageously be performed automatically. An inspection can then be performed on the optical element. In the positioning step, the holding device can be moved, or the optical element can be moved, or both can be moved.

[0022] According to one embodiment, in the positioning step, the contact surface of the movable ring can be biased to abut against the optical element by means of a biasing device, in which case the abutment of the movable ring against the optical element can be reliably achieved regardless of the spatial orientation of the holding device.

[0023] Examples of the approach presented herein are illustrated in the drawings and explained in more detail in the following description. [Brief explanation of the drawings]

[0024] [Figure 1] 1 is a schematic cross-sectional view of one embodiment of a holding device for holding an optical element for inspection. [Figure 2] 1 is a schematic cross-sectional view of an embodiment of a holding device with a biasing device for holding an optical element for inspection. [Figure 3] 1 is a flow chart of one embodiment of a method for holding an optical element for inspection. DETAILED DESCRIPTION OF THE INVENTION

[0025] In the following description of preferred embodiments of the invention, the same or similar reference numerals are used for elements that are shown in different figures and have similar effect, and repeated descriptions of these elements are omitted.

[0026] 1 shows a schematic cross-sectional view of one embodiment of a holding device 100 for holding an optical element OE for inspection. The holding device 100 is configured to hold an optical element OE, e.g. a lens, at least during inspection of the optical element OE or during a measurement and alignment process, also referred to as a test piece.

[0027] The holding device 100 includes a base 110, a fixed ring 120, and a movable ring .

[0028] The base body 110 is hollow and preferably formed in a hollow cylindrical shape. The fixing ring 120 is disposed on or fixed to the base body 110. The fixing ring 120 has a contact surface or first contact surface 122 at one axial end for abutting against the optical element OE. The movable ring 130 is attached to the base body 110 so as to be axially displaceable relative to the fixing ring 120 and the base body 110. The movable ring 130 has a contact surface or second contact surface 132 at one axial end for abutting against the optical element OE. The fixing ring 120 and the movable ring 130 are disposed coaxially with each other. Furthermore, at least a gap 140 is disposed between the fixing ring 120 and the movable ring 130. A vacuum can be generated in the gap 140 to hold the optical element OE. The fixing ring 120 and the movable ring 130 are radially spaced apart from each other by the gap 140.

[0029] In particular, the base 110 serves as a mounting for the fixed or stationary ring 120, or in other words as a support for the fixed ring 120, and as a guide for the movable ring 130. Furthermore, the holding device 100 can be attached at the base 110, for example, to an inspection device, or in particular to an actuator of the inspection device.

[0030] The movement of the axially displaceable mobile ring 130 takes place along an axis A. According to the embodiment shown here, at least the base body 110, the fixed ring 120 and the mobile ring 130 are oriented in the direction of the axis A and in particular are rotationally symmetrical with respect to the axis A. The axis A represents, for example, an axis of symmetry and / or a main axis of the holding device 100.

[0031] According to the embodiment shown, the movable ring 130 is arranged radially inside the fixed ring 120. Furthermore, a through opening 134 is formed in the movable ring 130 axially throughout the entire movable ring 130 or along the axis A. The through opening 134 can also be referred to as an aperture. This aperture extends along the axis A through the entire retention device 100. According to another embodiment, the fixed ring 120 can be arranged radially inside the movable ring 130. Furthermore, the through opening 134 can be formed in the fixed ring 120 axially or along the axis A through the entire retention device 100.

[0032] Furthermore, according to the illustrated embodiment, the contact surfaces 122 and 132 of the rings 120 and 130 are configured as cutting edges. The holding device 100 can therefore also be referred to as a vacuum double-ring cutting edge. In particular, the contact surfaces 122 and 132 are thus configured to abut against the optical element OE along concentric circles. In the case of rotationally asymmetric test pieces, such as cylindrical lenses, the rings 120 / 130 can have a correspondingly rotationally asymmetric concentric geometric shape.

[0033] According to the embodiment shown, the base body 110 also has a guide surface or guide portion 112. The guide portion 112 is configured to guide the movement of the movable ring 130 relative to the base body 110 and the fixed ring 120. In this case, a fitting portion 150, in particular a loose fitting portion, is provided as a sliding guide between the guide portion 112 of the base body 110 and the guided portion 136 of the movable ring 130.

[0034] According to another embodiment, the base 110 may additionally or alternatively comprise guide means configured to guide the movement of the mobile ring 130 relative to the base 110 and the fixed ring 120. Such guide means may in particular comprise a membrane guide or the like.

[0035] According to one embodiment, the base 110 has at least one stop portion 114. The stop portion 114 is configured to limit movement of the movable ring 130 relative to the base 110 and the fixed ring 120. In other words, the stop portion 114 is configured to limit axial movement of the movable ring 130 in at least one direction along the axis A.

[0036] Additionally or alternatively, according to one embodiment, a shoulder 138 is formed on the movable ring 130. The shoulder 138 is shaped or formed to limit movement of the movable ring 130 relative to the base 110 and the fixed ring 120. In other words, the shoulder 138 is formed to axially limit movement of the movable ring 130 in at least one direction along the axis A.

[0037] In particular, according to one embodiment, the stop portion 114 and the shoulder portion 138 can cooperate to limit movement of the movable ring 130 relative to the base 110 and the fixed ring 120 .

[0038] According to one embodiment, the movable ring 130 is formed integrally or in one piece. Alternatively, the movable ring 130 is made of several parts, in particular a first part 160 and a second part 170. In this case, the contact surface 132 is arranged on the first part 160 of the movable ring 130, and the guided part 136, which is guided through the base body 110, is arranged on the second part 170 of the movable ring. The first part 160 and the second part 170 of the movable ring 130 are connected to each other.

[0039] 2 is a schematic cross-sectional view of an example of a holding device 100 with a biasing device for holding an optical element to be inspected. The holding device 100 is identical to the holding device of FIG. 1 except that the holding device 100 also includes a biasing device 280.

[0040] The biasing device 280 is configured to bias the movable ring 130 in a direction away from the base 110. In this regard, the biasing device 280 includes, for example, elastic means, such as a spring or air pressure means, for moving the movable ring 130 in a direction away from the base 110 and / or in a direction towards the optical element OE.

[0041] The biasing device 280 is shown here, merely by way of example, positioned between the end of the movable ring 130 facing away from the optical element OE, e.g., the same end of the second part 170, and the end of the base 110 facing away from the optical element OE.

[0042] 3 shows a flowchart of one embodiment of a method 300 for holding an optical element for inspection. The holding method 300 includes a positioning step 302 and a generating step 304. In the positioning step 302, a holding device from one of the figures above, or a similar holding device, is placed with its contact surface against the optical element. Then, in the generating step 304, a vacuum is generated within the gap of the holding device to hold the optical element.

[0043] According to one embodiment, the contact surface of the movable ring is biased into abutment against the optical element by a biasing device in the positioning step 302. Such a biasing device is shown, for example, in FIG.

[0044] With reference to the above figures, the following will summarize and briefly paraphrase the embodiments and their advantages.

[0045] According to the embodiment, it is possible, in particular, to measure and hold the test piece or optical element OE simultaneously and from the same direction, without the holding or holding device 100 influencing the measurement. The holding device 100 is thereby produced test piece-independently and is therefore universally usable. The holding device 100 can be attached or is attached to an actuator that moves the optical element OE (also referred to as test piece).

[0046] According to the embodiment, when inspecting the optical element OE, it is possible to avoid the need to perform measurements through a glass window. Such measurements are often subject to errors, since glass windows are subject to influences that are not easily quantifiable and which vary. This can be prevented, in particular, by the through-opening 134. Since it is often not possible to grip the optical element OE at its periphery when there is no clearance between the test piece or the optical element OE and the holding device, according to the embodiment, an advantageous alternative holding can be made possible. In contrast to holding at the periphery, holding by the holding device 100 is also universal, since the holding device 100 can be adapted to any or almost any test piece geometry.

[0047] The holding device 100, specially manufactured as a vacuum double ring cutting edge (VDR), provides secure holding of the test piece or optical element OE during the measurement and alignment process or during inspection. The vacuum double ring cutting edge or holding device 100 does not directly affect the measurement results. Furthermore, the universal vacuum double ring cutting edge or holding device 100 is particularly adapted to the geometry of multiple test pieces in one assembly process.

[0048] According to an embodiment, the holding device 100 can establish a firm frictional coupling between the test piece or optical element and a peripheral device, which can be an actuator. The windowless, free aperture or through-opening 134 can avoid any influence on the measurement. This allows for use in any device where interference from a window would have a significant effect. The universal application of the holding device 100 saves time and money, thereby providing added value.

[0049] According to an embodiment, one of the two rings 120 and 130, i.e., the movable ring 130, is mounted so that it can be displaced perpendicular to the holding direction. The fixed or stationary ring 120 defines a position, while the movable ring 130 fits the test piece or optical element OE and establishes a vacuum. The contact between the movable ring 130 and the test piece or optical element OE can be established by gravity or by biasing using a biasing device 280, and is therefore usable in any orientation. In this case, an aperture or through-opening 134 in the inner ring, i.e., the movable ring 130, allows interference-free measurements. A vacuum is created in the gap 140 between the two rings 120 and 130. On the one hand, the movable ring 130 can be easily moved to fit the contours of the optical element OE, and on the other hand, the vacuum can be established by narrow guides and the concentricity of the rings 120 and 130.

[0050] The movement of the movable ring 130 can also be achieved by using a membrane guide instead of the mating portion 150 as a sliding guide. The bias can be generated by gravity or other force storage means such as a spring or compressed air as the biasing device 280. The movable ring 130 can be made in one piece or in multiple pieces. [Explanation of symbols]

[0051] 100 Holding device 110 Base 112 Guide part 114 Stopper part 120 fixing ring 122 Contact surface 130 Movable Ring 132 Contact surface 134 Through opening 136 Guided part 138 Shoulder 140 Gap 150 Fitting part 160 First Part 170 Second Part 280 Actuating device 300 ways 302 Placement Step 304 Generation Step OE Optical Elements

Claims

1. A holding device (100) for holding an optical element (OE) for inspection, the holding device (100) comprising: a hollow substrate (110) that can be attached to or is attached to an actuator that moves the optical element (OE); a fixing ring (120) disposed on or fixed to the base (110) and having a contact surface (122) at one axial end thereof for contacting the optical element (OE); a movable ring (130) supported on the base (110) so as to be displaceable in the axial direction relative to the fixed ring (120) and the base (110) so as to fit the contour of the optical element (OE), the movable ring (130) having a contact surface (132) at one axial end for abutting against the optical element (OE); The fixed ring (120) and the movable ring (130) are arranged coaxially with each other, a gap (140) capable of generating a vacuum for holding the optical element (OE) is disposed at least between the fixed ring (120) and the movable ring (130); A holding device (100) in which the contact surfaces (122, 132) of both rings (120, 130) are formed as cutting edges, the gap (140) is formed between the cutting edges of both rings (120, 130), and the holding device can establish a firm frictional force connection between the optical element (OE) and the actuator.

2. The retention device (100) of claim 1, wherein the movable ring (130) is disposed radially inward of the fixed ring (120).

3. The retention device (100) of claim 1, wherein the movable ring (130) is disposed radially outward of the fixed ring (120).

4. The holding device (100) according to any one of claims 1 to 3, wherein the base body (110) has a rotationally symmetric or rotationally asymmetric geometric shape.

5. A retaining device (100) according to any one of claims 1 to 3, wherein a through opening (134) is formed in the movable or fixed ring (120, 130) axially penetrating the entire movable or fixed ring (120, 130).

6. The holding device (100) according to any one of claims 1 to 3, wherein the contact surfaces (122, 132) are formed to abut against the optical element (OE) along a concentric, rotationally symmetric or rotationally asymmetric geometric shape.

7. The holding device (100) according to any one of claims 1 to 3, further comprising a biasing device (280) for biasing the movable ring (130) in a direction away from the base body (110), in particular the biasing device (280) having elastic means or compressed air means.

8. The holding device (100) according to any one of claims 1 to 3, wherein the base (110) has a guide portion (112) formed to guide movement of the movable ring (130) relative to the base (110) and the fixed ring (120).

9. 9. The holding device (100) according to claim 8, wherein a fitting portion (150), in particular a play fitting portion, is configured as a sliding guide between the guide portion (112) of the base body (110) and the guided portion (136) of the movable ring (130).

10. A holding device (100) according to any one of claims 1 to 3, comprising guide means provided on the base body (110), which guide means are configured to guide the movement of the movable ring (130) relative to the base body (110) and the fixed ring (120), in particular the guide means comprising a membrane guide.

11. The retaining device (100) according to any one of claims 1 to 3, wherein the base (110) has at least one stop portion (114), which is formed to limit movement of the movable ring (130) relative to the base (110) and the fixed ring (120).

12. The retaining device (100) of any one of claims 1 to 3, wherein the movable ring (130) is formed with a shoulder (138), the shoulder (138) being configured to limit movement of the movable ring (130) relative to the base body (110) and the fixed ring (120).

13. The retaining device (100) according to any one of claims 1 to 3, wherein the movable ring (130) is integrally formed.

14. The movable ring (130) is made of multiple parts, The contact surface (132) is disposed on a first part (160) of the movable ring (130); A guided portion (136) that is guided through the base body (110) is disposed on the second part (170) of the movable ring (130), The retaining device (100) according to any one of claims 1 to 3, wherein the first part (160) and the second part (170) of the mobile ring (130) are connected to each other.

15. 1. A method (300) for holding an optical element (OE) for inspection, the method (300) comprising: - a step (302) of placing a holding device (100) according to any one of claims 1 to 3 in contact with an optical element (OE) with the contact surfaces (122, 132); and creating (304) a vacuum in the gap (140) to hold the optical element (OE).

16. 16. The method (300) of claim 15, wherein in the placing step (302), the contact surface (132) of the movable ring (130) is biased into abutment against the optical element (OE) using a biasing device (280).

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