Method and apparatus for slicing a multi-layer glass element

Abstract

The application provides a method for manufacturing a light guide optical element (1) blank from a composite glass stack (3) comprising a plurality of glass sheets (5) bonded together and a light reflecting layer (7) disposed therebetween, the method comprising cutting a slice (9) from the composite glass stack (3) along a parallel cutting plane (11). Aligning the composite glass stack (3) with the cutting plane (11) comprises: - adjusting the tilt angle of a plane (16) with the cutting plane (11) with a collimator (22); and - adjusting the position of the stack (3) in the direction of the tilt preferably perpendicular to the cutting plane (11). The composite glass stack (3) is fixed on a holder (23) in the direction of its alignment and cut into a blank forming a light guide optical element (1).

Description

[0001] This invention is a divisional application of Chinese Patent Application No. 202411029769.6, entitled "Method and apparatus for slicing multilayer glass elements", filed on July 30, 2024. Technical Field

[0002] This invention generally relates to the technical field of manufacturing glass-based optical elements. In particular, this invention relates to the precision cutting of glass slices to obtain optical elements. Background Technology

[0003] In some applications, complex optical components are required. These complex optical components may comprise a large number of stacked glass layers with intermediate functional optical layers, such as light-reflecting and / or polarizing layers. These components can be used as waveguide elements, for example, in near-eye displays. For such applications, the structuring of the optical elements is used to extend a small image to a large field of view. The optical elements can then be worn as a transparent screen or spectacle lens, displaying images from a small side-mounted screen, which are superimposed on an image of the environment seen through the lens. To properly guide and superimpose the projected and superimposed image onto the image of the environment seen by the wearer of such a near-eye display, each layer of the stacked layers should be positioned and oriented with high precision relative to its surface or interface. A method for manufacturing such optical elements (also known as light-guide optics) is described in WO 2021 / 240515 A1. Generally, this method is based on stacking and bonding multiple coated transparent plates together to form an optical block, and then slicing the optical block at predetermined intervals to form multiple light-guide optics. However, since precise orientation of each layer within the stack is required, the separation of the optical guide element from the optical block is particularly important, as the orientation and position relative to the separation plane of the optical block define the orientation of each layer within the separation element. Therefore, the object of this invention is to improve the accuracy of separating slices from a multilayer block. The subject matter of the independent claims addresses this objective. Beneficial improvements of the invention are defined in the dependent claims. Summary of the Invention

[0004] Therefore, this article provides a method and apparatus for manufacturing a light guide optical element blank from a composite glass stack, wherein the composite glass stack comprises a plurality of glass plates bonded together, and a light-reflecting layer disposed between the glass plates. The method includes cutting slices from the composite glass stack along a parallel cutting plane. The method further includes aligning the composite glass stack with the cutting plane such that the light-reflecting layer has a defined orientation relative to the side surface of the slice after cutting. Advantageously, the alignment is performed before cutting. The composite glass stack has a plane having a defined orientation relative to the light-reflecting layer within the composite glass stack, such that the light-reflecting layer within the slice is correctly oriented when the cutting plane extends along the plane parallel to the composite glass stack. The alignment of the composite glass stack with the cutting plane includes: - Adjust the tilt angle of the plane of the composite glass stack relative to the cutting plane using an autocollimator; and - The position of the composite glass stack is adjusted at an angle, preferably perpendicular to the cutting plane.

[0005] The composite glass stack is held and fixed in a holder along its alignment direction and cut into slices. These slices form blanks for the light-guiding optical element. Depending on the structure of the blanks, these blanks can be directly processed into light-guiding optical elements or incorporated into other slices. In the latter case, the blanks are intermediate products for the production of light-guiding optical elements. For example, the slices can be used to produce another composite glass stack. This glass stack can then be sliced ​​again using the methods described herein to produce blanks for the production of light-guiding optical elements.

[0006] Preferably, the slices are cut from the composite glass stack using a wire saw with one or more cutting wires and a large number of parallel sections. In this case, the longitudinal direction of the cutting wires and the forward direction of the composite glass stack relative to the movement of the cutting wires cross the cutting plane.

[0007] The light-reflecting layer described herein can be, in particular, a semi-reflective layer, which reflects a certain proportion of incident light according to the parameters of the light (e.g., tilt angle, polarization, or wavelength). Attached Figure Description

[0008] The present invention will now be described in more detail with reference to the accompanying drawings.

[0009] Figure 1 A perspective view of the composite glass stack is shown.

[0010] Figure 2 A front view of the composite glass stack is shown.

[0011] Figure 3 It shows from Figure 2 The slice shown is a cut of the composite glass stack.

[0012] Figure 4 An apparatus for slicing composite glass stacks is shown, the apparatus having means for aligning the composite glass stacks with the cutting plane.

[0013] Figure 5 The diagram shows various misalignments of the light-reflecting layer compared to a correctly aligned light-reflecting layer.

[0014] Figure 6 Two autocollimator sketches are shown before and after the composite glass stack is aligned.

[0015] Figure 7 A schematic sketch of a camera used to adjust the lateral position of a composite glass stack is shown.

[0016] Figure 8 The composite glass stack used for testing is shown.

[0017] Figure 9 An apparatus for offline measurement of tilt angle is shown.

[0018] Figure 10 The steps for coarse adjustment of the tilt angle are shown.

[0019] Figure 11 The coarse adjustment of the azimuth tilt angle is shown.

[0020] Figure 12 The alignment device is shown. Detailed Implementation

[0021] Figure 1 and Figure 2 A perspective view of the composite glass laminate and a front view of one side of the composite glass laminate are shown. According to one embodiment, such as... Figure 1 As shown in the perspective view, the composite glass stack 3 includes a large number of light-reflecting layers 7 facing parallel to the side surface 17 of the composite glass stack 3. Generally, not limited to the illustrated embodiment, the light-reflecting layers 7 are spaced apart from each other at a certain interval along their normal direction or in a direction perpendicular to their surface. Figure 2 As shown, the composite glass stack 3 comprises a large number of glass plates 5 bonded together by bonding layers 6. These bonding layers 6 can be optical adhesive layers or adhesive layers. Generally, the thickness of the bonding layer 6 is preferably in the range of 0.5 μm to 6 μm, more preferably in the range of 0.75 μm to 5 μm, even more preferably in the range of 1 μm to 4 μm, and particularly in the range of 1 μm to 3 μm.

[0022] Light-reflecting layers 7 are disposed between glass plates 5. Preferably, these light-reflecting layers 7 are produced by depositing a layer material on one of the surfaces of the glass plates 5. Figure 2 The intended cutting plane 11 is also shown with dashed lines. Preferably, the distance between the cutting planes 11 is selected to match the distance between the light-reflecting layers 7, such that in the slices produced by cutting along the cutting planes 11, the light-reflecting layers 7 are arranged such that their distances from the sides of the slice are equal. In a preferred embodiment, the composite glass stack 3 is cut such that the light-reflecting layers 7 in the slices are centrally located between the sides of the slices. Thus, without being limited to the specific embodiment shown, the composite glass stack 3 includes a large number of light-reflecting layers 7 oriented parallel to the sides 17 of the composite glass stack 3, wherein the step of adjusting the position of the composite glass stack 3 in a direction perpendicular to the cutting plane 11 includes adjusting the position of the composite glass stack 3 such that the light-reflecting layers 7 are centrally located within the slice 9 in a direction perpendicular to the sides of the slice. For example, an optical element having a centrally located reflective layer serving as a hybrid layer is known from US2022 / 0091413 A1.

[0023] In the illustrated example, the glass plates 5 have the same thickness. However, in a preferred embodiment, the thickness of the outer glass plates 50 forming the side surfaces 17 of the composite glass stack 3 may differ from the thickness of the glass plates 5 sandwiched between these outer glass plates 50. More preferably, the thickness of the outer glass plates 50 forming the side surfaces 17 is greater than the thickness of the inner glass plates 5 sandwiched between the outer glass plates 5, 50. In one example, the thickness of the outer glass plates 50 is 5 mm, and the thickness of the inner glass plates 5 is 1.55 mm. Generally, without being limited to specific examples, the thickness of the inner glass plates 5 can be in the range of 1 mm to 3 mm. Furthermore, without being limited to specific examples, the composite glass stack 3 may have at least 10, preferably 10 to 60, more preferably 20 to 50 inner glass plates 5 sandwiched between the outer glass plates 50. Therefore, according to the improvement of the method, at least 9, preferably 9 to 59, more preferably 19 to 49 slices can be cut from the composite glass stack 3 to form blanks for optical guide elements.

[0024] In one example, glass panel 5 is made of N-BK7 glass. The dimensions of the composite glass laminate are 70×70×70mm. 3 The dimensional tolerance is + / - 0.3 mm. The side surface 17 formed by the outer glass plate 50 can be a D151 ground surface or a finer surface; in particular, these sides can be polished. The top and bottom sides can have a slightly lower surface quality, for example, they can be ground surfaces. The edges can be chamfered to a maximum of 0.5 mm.

[0025] Figure 3It shows from such Figure 1 , Figure 2 The cut slice 9 is shown as a composite glass stack cut from a cutting plane 11. Slice 9 has sides 13 and 15 formed by cutting the composite glass stack 3 along the cutting plane 11. As described above, preferably, the light-reflecting layer 7 is centrally disposed between the sides 13 and 15.

[0026] According to one embodiment, slice 9 can form light-guiding optical element 1, for example, after slicing slice 9 along a predefined contour and / or after finishing the sides 13, 15. Therefore, according to one embodiment, a method for producing light-guiding optical element 1 is provided, comprising: generating slice 9 from composite glass stack 3 using the methods described herein, polishing the sides 13, 15 of slice 9, and slicing slice 9 along a predefined contour to obtain light-guiding optical element 1. In another embodiment, slice 9 is an intermediate product of light-guiding optical element 1, wherein slice 9 is again stacked with other slices of generally different structures to form another composite glass stack, which can then be sliced ​​again using the methods disclosed herein.

[0027] In contrast, in the preferred embodiment, the position of the composite glass stack 3 relative to the cutting plane 11 is adjusted such that the positional deviation of the light-reflecting layer 7 relative to a reference position within the slice 9 cut from the composite glass stack 3 is less than 0.2 mm, preferably less than 0.1 mm. As described above, preferably, the reference position is the center position of the slice 9 between its sides 13 and 15. Therefore, if the light-reflecting layer 7 is located at the center of the slice, the distance difference between the light-reflecting layer 7 and the sides 13 and 15 of the slice after slicing and polishing is less than 0.2 mm, or even less than 0.18 mm.

[0028] The centered position of the light-reflecting layer 7 within the slice is only one of several parameters for correct orientation. Particularly important is the tilt angle of the light-reflecting layer 7 relative to a reference plane. This reference plane can, in particular, be one side 13 or 15 of the slice 9. According to a preferred embodiment, the orientation of the composite glass stack 3 relative to the cutting plane 11 is adjusted by means of an autocollimator, such that the tilt angle of the light-reflecting layer 7 of the slice 9 cut from the composite glass stack 3 is less than 15 arcseconds or less than 0.004166 degrees.

[0029] The following will provide a detailed explanation of adjustment and slicing. Figure 4 A schematic diagram of a cutting device 2 for cutting slices from a composite glass stack 3 is shown. The cutting device 2 includes a wire saw 21 having one or more cutting wires 18 and a large number of parallel segments 180. For example, a single cutting wire 18 can be guided in a zigzag manner around spaced bearings. Thus, adjacent parallel segments 180 of the cutting wire 18 advance in opposite directions, such as... Figure 4 As shown by the two arrows in the image.

[0030] The composite glass stack 3 is held by the retainer 23 and cut by moving the composite glass stack 3 relative to the cutting wire 18.

[0031] The composite glass stack 3 is aligned using an alignment device 10. In this example embodiment, the alignment device 10 includes three stacked worktables 32, 33, and 34, preferably miniature worktables, wherein two worktables 32 and 33 adjust their tilt angles α and β in a non-parallel plane (particularly in a vertical plane). Figure 4 As can be seen, the tilt angle β is the azimuth angle of rotation about the axis along the cutting direction. Another worktable 34 is provided for linear displacement along a direction tilted relative to the cutting plane 11, preferably linear displacement perpendicular to the cutting plane 11. One of the parallel segments 180, the cutting plane 11, is indicated by a dashed line. Therefore, generally, without being limited to the specific example shown, the alignment device 10 includes stacked worktables 32, 33, and 34, wherein... - The worktable 32 is configured to adjust or manipulate the azimuth angle of the composite glass stack about the axis along the cutting direction. - The worktable 33 is configured to adjust or manipulate the angle of rotation of the composite glass stack 3 about an axis inclined (preferably vertical) relative to the cutting plane 11, and - The worktable 34 is configured to adjust or manipulate the position of the composite glass stack 3 along a direction inclined (preferably vertical) relative to the cutting plane (11).

[0032] Therefore, the method for manufacturing a blank according to this embodiment includes fixing the composite glass stack 3 onto a retainer 23 that is movable via stacked worktables 32, 33, and 34; - Use one of the worktables 32 to adjust or manipulate the azimuth angle of the composite glass stack 3 about the axis along the cutting direction; - Use one of the worktables 33 to adjust or manipulate the angle of rotation of the composite glass stack 3 about an axis inclined (preferably perpendicular) to the cutting plane 11; and - Use one of the worktables 34 to adjust or manipulate the position of the composite glass stack 3 in a direction inclined (preferably perpendicular) to the cutting plane 11.

[0033] Unlike the described embodiment, the worktable can be configured for combined adjustment of two parameters, such as adjusting two tilt angles α and β. In this case, only two worktables are required.

[0034] Preferably, the composite glass stack 3 is cut into slices of blanks forming optical guide elements by moving a holder 23 with the fixed composite glass stack 3 relative to one or more cutting lines 18 using a large worktable or a propulsion device 35. Preferably, cutting is performed by moving the holder 23 with the fixed composite glass stack 3 downward.

[0035] In the preferred embodiment, also as Figure 4 As shown in the example, the composite glass stack 3 is bonded to a sacrificial substrate or plate 27 fixed to a holder. Therefore, the cutting process involves completely cutting through the composite glass stack 3 and further partially cutting into the sacrificial plate 27. After cutting, the bond between the sacrificial plate 27 and the composite glass stack 3 is released or released, allowing the slice 9 to separate from the sacrificial plate 27. Preferably, for this purpose, the composite glass stack is bonded to the sacrificial plate 27 using a releasable cement, particularly a UV releasable cement or a thermally releasable cement.

[0036] In one Figure 4 In the example implementation, the autocollimator 22 is fixedly arranged with the cutting device 2, particularly the wire saw 21. This allows the tilt angles of the composite glass stack 3 to be aligned linearly within the cutting device.

[0037] Furthermore, generally, adjusting the position of the composite glass stack 3 so that the light-reflecting layer 7 is centered within the slice 9 along a direction perpendicular to the sides 13, 15 preferably includes monitoring the position of at least one light-reflecting layer 7 via a camera 24. In one embodiment, as also Figure 4 As shown in the example, camera 24 is also fixedly arranged with cutting device 2, particularly wire saw 21, so that the position of the composite glass stack 3 can be adjusted in-line (particularly using worktable 34). In an exemplary embodiment, camera 24 is positioned along the forward direction of composite glass stack 3. However, camera 24 can also be positioned for observation along the longitudinal direction of parallel segments 180 of one or more cutting lines 18. It has been demonstrated that image control by camera 24 is highly precise in adjusting the position of composite glass stack 3 in a direction inclined, preferably perpendicular, to cutting plane 11, such that after slicing and polishing, the absolute value of the distance difference between light-reflecting layer 7 and the sides 13, 15 of slice 9 is less than 0.18 mm. This feature can also be achieved through other embodiments disclosed herein. Preferably, as also Figure 4 As shown in the example, camera 24 is configured to image at least one light-emitting layer 7 along its edge. This enables precise positioning of the composite glass stack 3.

[0038] To adjust the tilt angle or tilt angles α and β separately, the autocollimator 22 can monitor the tilt angle of one of the inner surfaces of the composite glass stack 3, such as the tilt angle of one of the light-emitting layers 7 in the light-emitting layers 7. In this case, the autocollimator is advantageously configured to monitor the tilt angle of the light-emitting layer 7 closest to the autocollimator 22. In another embodiment, it also... Figure 4 In the example implementation, the plane 16 of the composite glass stack 3 having a defined orientation relative to the light-reflecting layer 7 is the side surface 17 of the composite glass stack 3. For this embodiment, it is advantageous to adjust the orientation of the side surface of the composite glass stack 3 if the side surface 17, monitored at least by the autocollimator 22, has a polished surface quality. For example, the side surface 17 can be a polished surface.

[0039] Figure 5 The images show various misalignments in slice 9 caused by improper alignment of the composite glass stack 3 before slicing, resulting from the light-reflecting layer 7. In case (a), the tilt angle α is greater than 15 arcseconds. In case (b), the tilt angle β exceeds 10 arcseconds. Case (c) shows a misalignment where the distance difference z1-z2 between layer 7 and sides 13, 15 exceeds 0.18 mm. Of course, a defective slice 9 may have more than one such misalignment. Case (d) shows proper alignment where all the constraints shown in partial images (a) to (c) are met. Furthermore, after polishing slice 9, for example, for a slice with a thickness of 1.2 mm, the thickness tolerance of slice 9 can be limited to a maximum of 0.05 mm.

[0040] Figure 6 Two images (a) and (b) of the display screen of the autocollimator 22 are shown. Image (a) shows the display screen of the autocollimator 22 before the composite glass stack 3 is aligned. The tilt angles α1 and β1 are shown as mutually perpendicular straight lines, and are off-center from the display screen due to misalignment. As shown, the center can be marked with a crosshair. The autocollimator is also aligned with the cutting plane 11, so adjusting the tilt angle of the plane 16 of the composite glass stack 3 relative to the cutting plane 11 by using the autocollimator 22 includes adjusting the orientation of the composite glass stack 3 so that the straight lines representing the tilt angles α and β are centered or intersect at the center of the display screen, thus also matching the crosshair. Figure 6 Image (b) illustrates this state.

[0041] Figure 7 Further shown Figure 4The camera 24 shown displays an image for adjusting the lateral position of the composite glass stack. The camera 24 images the light-reflecting layer 7 along the edge and through one or more parallel segments 180 arranged along the cutting lines. To adjust the position of the composite glass 3 in a direction inclined (preferably perpendicular) to the cutting plane 11 (as in the embodiment discussed here, this position is where the light-reflecting layer 7 is located at the center of the slice 9), the position of the composite glass stack 3 is adjusted so that the light-reflecting layer 7 is centered between the faces 180 in the image. In the example shown, the position of the composite glass stack 3 needs to be adjusted so that the light-reflecting layer 7 is slightly moved to the right in the image shown.

[0042] To ensure a suitable orientation of the composite glass stack 3 relative to the cutting plane 11, the orientation of the autocollimator 22 relative to the holder 23 is advantageously aligned and / or corrected according to a preferred refinement scheme. According to this refinement, adjusting the orientation of the autocollimator 22 relative to the cutting plane 11 involves: adjusting the tilt angle of the plane 16 of the test composite glass stack 30 relative to the cutting plane 11 using the autocollimator 22; cutting the composite glass stack 30 into slices 9; placing one of the sides 13, 15 of one of the slices (preferably the outermost slice 9, particularly the slice 9 including the side of the composite glass stack 30 facing the autocollimator) onto the reference surface 25; measuring the tilt angle of the plane 16, preferably measuring the tilt angle of the sides 15, 13 opposite to the sides 13, 15 placed on the reference surface 25; and correcting the orientation of the autocollimator 22 relative to the cutting plane 11. Similarly, the position and orientation of the camera 24 can be corrected.

[0043] For initial conditioning purposes, it is not necessary to use a fully equipped composite glass stack 3 with a large number of light-reflecting layers 7. Instead, a composite glass stack for simulation or testing can be used. Figure 8 An example of this test composite glass stack 30 is shown. For adjusting the settings of the autocollimator 22 and / or camera 24, a single panel with the light-reflecting layer 7 is sufficient. Figure 8 In one example, the test composite glass stack 30 includes three simulated glass plates 37 and a hybrid glass plate 36 sandwiched between two of the stacked simulated glass plates 37. For alignment purposes, the hybrid glass plate 36 may have a light-reflecting layer (not shown). In one example, the thickness of the simulated glass plate 37 (i.e., the distance between sides 13, 15) is approximately 20 mm, and the thickness of the hybrid glass plate is approximately 6 mm.

[0044] Figure 9A device for determining the adjustment of the autocollimator 22 is shown. After the composite glass stack 3, or preferably the test composite glass stack 30, is cut into slices 9, one of the slices 9 is placed on a reference surface 25, such as a support 26. The support 26 may be, for example, a granite slab. The tilt angles α1 and β1 of the side 13 opposite to the side 15 located on the reference surface 25 are then measured. For this purpose, an outermost cut slice 9 is used, such that the side 17 of the composite glass stack 3 forms the side 13 of the slice 9. This is advantageous because the side may already have a polished surface quality, while the other side may have a higher roughness due to the cutting process. Thus, the side 13 forms a plane 16, and the tilt of the plane 16 relative to the cut plane 11 is measured. Alternatively, an inner slice 9 can be used, and the tilt angle in this case can be determined based on the tilt angle of the light-reflecting layer 7 within the slice. Preferably, the tilt angle is determined again using the autocollimator 22. The autocollimator 22 can be removed from the cutting device 2 and installed on Figure 9 On the device, or alternatively, another autocollimator can be used. In any case, the orientation of the autocollimator relative to the reference surface 25 is calibrated such that the measured tilt angles α1, β1 can be used to correct the adjustment of the autocollimator 22 of the alignment device 10. Therefore, the correction of the position and orientation of the autocollimator is determined in offline measurements. Typically, the outer slice 9 used for tilt angle measurement is different from the inner slice 9. After processing the conventional composite glass stack 3, usually only the inner slice has the same characteristics as... Figure 3 As shown in the diagram, the outer slice 9 cannot be used as a blank for the optical guide element 1. For example, from... Figure 2 As can be seen, this is obvious because the outer slice does not contain the light-reflecting layer 7.

[0045] Generally, during the routine operation of the cutting device 2, the tilt angle can be controlled at least once between processing two composite glass stacks 3, i.e., between the cutting steps of the two stacks. Specifically, after cutting the composite glass stack 3, as described above, the orientation tilt of the slice 9 can be determined offline by placing the slice 9 on the reference surface 25. Advantageously, the tilt angles of a large number of slices 9 can be measured, and an average tilt angle can be determined based on these tilt angles to improve accuracy. Figure 9As shown, in the case of misalignment, unlike the outer slice 9, the inner slice 9 generally has parallel sides 13, 15. Therefore, in this case, the tilt of the inner surface, particularly the tilt of the light-reflecting layer 7, is used for measurement. Therefore, in an improved embodiment, the method includes: cutting a first composite glass stack 3 to form slice 9, and subsequently cutting a second composite glass stack 3, wherein one side of the numerous slices 9 cut from the first composite glass stack is placed on a reference surface 25, and the tilt angle of the inner surface of the slice 9 (particularly the light-reflecting layer 7) relative to the reference surface 25 is measured, and an average tilt angle is determined, and wherein the orientation of the autocollimator 22 is corrected based on the average tilt angle, and the second composite glass stack 3 is cut using its tilt angle relative to the cutting plane 11, which is adjusted using the autocollimator 22 and along the direction from which it is corrected. In addition to orientation, these steps can also be performed specifically using a test composite glass stack 30.

[0046] Of course, such as Figure 9 As shown, this embodiment can also be combined with measuring the tilt angle of the outer slice (especially measuring the tilt angle of one of the sides 13 and 15). Therefore, the preferred process flow is as follows.

[0047] 1. Roughly set β using a dial gauge or Precitec sensor (measured on polished glass). 2. Use at least one camera 24 to roughly set α (align the plane 180 so that it is parallel to the top surface of the composite glass stack 3). 3. Align Autocollimator 22: Copy the vertical and horizontal lines on the autocollimator. 4. Slice the composite glass laminate 30 used for testing. 5. For reference Figure 9 The tilt angles α1 and β1 of the first or outer slice 9 of the composite glass stack 30 used for offline measurement and testing are described. 6. Install the composite glass laminate 3 onto the retainer 23, and adjust the tilt angles α and β on the worktables 32 and 33. 7. For reference Figure 9 The orientation of the autocollimator is corrected using tilt angles α1 and β1 determined through offline measurements. 8. Use worktables 32 and 33 to fine-tune the tilt angles α and β. 9. Use workbench 34 to fine-tune z. 10. Slice the composite glass laminate 3. 11. Measure α and β of all slices offline and determine the average values ​​of the tilt angles ͞α and ͞β. 12. Install the next composite glass stack 3, and adjust α and β on worktables 32 and 33. 13. Utilize Figure 9 The device corrects the direction of the autocollimator by using the average tilt angles α and β determined through offline measurements. 14. Fine-tune the tilt angles α and β on worktables 32 and 33. 15. Fine-tune z on workbench 34, and 16. Slice the composite glass stack 3.

[0048] refer to Figure 10 The text describes a rough setup of the first composite glass stack 3 to be sliced ​​(i.e., according to step 1 of the above process flow), which can in particular be a test composite glass stack 30. Figure 10 The image only schematically shows a retainer 23, which holds a sacrificial plate 27 to which the composite glass stack 3 is attached. Coarse adjustment or pre-adjustment of the tilt angle about a rotation axis inclined with respect to the direction of movement of the composite glass stack 3 during cutting is performed by measuring the positions of points on the surface of the composite glass stack 3 along the path of movement of the composite glass stack 3 during the cutting operation, and adjusting the orientation of the composite glass stack 3 based on the measurement results, specifically adjusting the orientation such that the positions have equal values ​​in a direction perpendicular to the surface. This trajectory direction is parallel to the cutting plane 11. Figure 10 Image (a) shows the composite glass stack 3 in the first position. Figure 10 Image (b) shows the composite glass stack 3 in a second position, which is offset from the first position along the path or in the direction of movement. The arrows in image (a) indicate the direction of movement. The position in the illustrated embodiment is measured using a measuring instrument 40. If the tilt angle is zero, the position values ​​of the measuring instrument are equal relative to the two positions. Preferably, the measurement is performed on the side 17 extending parallel to the cutting plane 11. Another position or distance-sensitive sensor, such as an optical sensor or a capacitive sensor, can be used instead of the measuring instrument or as a supplement to the measuring instrument.

[0049] Figure 11 Another pre-adjustment step corresponding to step 2 of the above process flow is shown. This pre-adjustment can adjust the azimuth tilt angle, the axis of rotation of which is along the cutting movement direction. For example, in... Figure 11As can be seen, for at least two points longitudinally spaced along line 18 on surface 17, at least one camera 24 measures the distance from surface 17 to the cutting line 18 or its segment 180. Advantageously, points close to the edge of surface 17 are selected to minimize measurement error. The orientation of the composite glass stack 3 is then adjusted so that distances a and b are equal, or more generally, their difference is minimized. In this example, two cameras 24 are used. Alternatively, the composite glass stack 3 can be moved along a direction parallel to the cutting line 18 and the distances recorded sequentially. Alternatively, a single camera with a sufficiently large field of view can be used so that the spaced-out points are within the field of view. Figure 11 It is obvious that distance is measured only in one direction perpendicular to the surface.

[0050] exist Figure 4 In the exemplary embodiments shown, alignment devices including worktables 32, 33, and 34, autocollimator 22, and camera 24 are disposed in the cutting device 2, or are respectively formed as part of the cutting device 2. According to another embodiment, the alignment of the composite glass stack 3 is performed outside the cutting device 2. This helps to avoid the components of the alignment device being affected by dust generated by the cutting device. The example described below is based on an embodiment in which, when the holder 23 is inserted and fixed in the cutting device 2, the holder 23 has a defined orientation relative to the cutting plane 11, and in which, when the holder 23 is disengaged from the cutting device 2 and fixed to the alignment device 10, the composite glass stack 3 is aligned with the holder 23, as monitored by the autocollimator 22, and fixed to the holder 23 along the alignment orientation, and in which the holder 23 with the composite glass stack 3 attached is inserted and fastened to the cutting device 2, thereby giving the composite glass stack 3 a defined orientation relative to the cutting plane due to its defined orientation relative to the holder 23. Then, the cutting operation can begin, and slices 9 can be cut with high precision. Figure 12 An alignment device 10 suitable for this embodiment is shown. For example, the alignment device 10 may include a substrate on which tools for alignment are mounted. These tools include a base 47 for adjusting the position and orientation of the composite glass stack 3 and the autocollimator 22. Preferably, a camera 24 is also mounted on the alignment device 10 to monitor the lateral position of the composite glass stack 3 relative to the cutting plane 11. Figure 4 As shown in the embodiment, the side surface 17 of the composite glass stack 3 can be used as a plane 16, which has a defined orientation relative to the cutting plane 11 of the cutting device 2.

[0051] A retainer 23 for the composite glass stack 3 is mounted on a fixture 42. If the position and orientation of the autocollimator 22 and camera 24 are properly calibrated, the autocollimator 22 and camera 24 have a defined alignment relationship with the retainer 23. Therefore, regarding the cutting operation, the retainer 23 will be fixed within the cutting device 2, also with a defined alignment relationship relative to the cutting plane 11. To fix the composite glass stack 3 in an aligned position and orientation on the retainer 23, the composite glass stack 3 can be moved and / or rotated using a base 47, while the autocollimator 22 and camera 24 monitor the tilt angle and lateral position of the composite glass stack 3. In the illustrated embodiment, similar to... Figure 4 In this embodiment, worktables 32, 33, and 34 are used to move base 47. However, alternatively or additionally, other adjustment tools may be used. For example, a manual universal joint, preferably a micrometer, may be used to operate the base.

[0052] Once alignment is achieved, the composite glass stack 3 is secured to the retainer 23. To secure the composite glass stack 3 to the retainer 23, an adhesive 44 is preferably used. For example, the alignment process can be performed during the curing of the adhesive 44, while the adhesive 44 is still flexible.

[0053] As in Figure 4 In the preferred embodiment, the composite glass stack 3 is not directly fixed to the retainer 23, but is fixed to the sacrificial plate 27, which is then fixed to the retainer 23.

[0054] In particular, according to Figure 12 The embodiments rely on the calibration of the alignment device 10. Therefore, refer to Figures 9 to 11 The described embodiments include using, for example Figure 9 The calibration of one of the outer slices shown, the determination of the average tilt angle of a large number of cut slices 9, and the appropriate correction of the autocollimator's orientation can also be used according to... Figure 12 Examples with offline alignment. However, it is possible to omit, for example, Figure 9 The attached device shown is for offline measurement of tilt angles. Alternatively, a device such as... Figure 12 The alignment device 10 shown is used for calibration.

[0055] This disclosure also relates to an apparatus for performing the method described herein. Therefore, the apparatus includes a cutting device 2 and an alignment device 10. The alignment device 10 may be as follows: Figure 4 Part of the cutting device 2 in the embodiment, or it may be a reference Figure 12 The individual device described.

[0056] Therefore, without being limited to the specific examples described herein, the apparatus is used to manufacture a blank of a light-guiding optical element 1 from a composite glass stack 3, the composite glass stack 3 comprising a plurality of glass plates 5 bonded together, and a light-reflecting layer 7 disposed between the glass plates 5, wherein the apparatus includes a cutting device 2 and an alignment device 10, the cutting device 2 for cutting slices 9 from the composite glass stack 3 along a parallel cutting plane 11, and the alignment device 10 for aligning the composite glass stack 3 with the cutting plane 11 such that, after cutting, the light-reflecting layer 7 has a defined orientation relative to the sides 13, 15 of the slice 9, wherein the composite glass stack 3 has a plane 16 having a defined orientation relative to the light-reflecting layer 7 within the composite glass stack 3, such that, when the cutting plane 11 extends parallel to the plane 16 of the composite glass stack 3, the light-reflecting layer 7 within the slice 9 has the correct orientation, wherein the apparatus includes a holder 23 for holding the composite glass stack 3 at its aligned orientation, and wherein the alignment device 10 includes: - Autocollimator 22, used to monitor the adjustment of the tilt angle of the plane 16 of the composite glass stack 3 relative to the cutting plane 11, and - A device for adjusting the position of the composite glass stack 3 in a direction inclined to (preferably perpendicular to) the cutting plane 11.

[0057] It will be apparent to those skilled in the art that the various embodiments described herein can be combined within the scope of the claims and are not limited to the specific examples shown in the accompanying drawings. For example, regarding Figure 12 The aforementioned offline adjustment can also be combined with Figure 4 The additional online adjustments shown are combined. Furthermore, the alignment of layer 7 extending parallel to the sides 13, 15 of slice 9 has been shown. However, this method can also be applied to the obliquely extended light-reflecting layer 7, which has a defined angle relative to the sides 13, 15.

[0058] List of reference numerals

Claims

1. A method for manufacturing a blank for an optical guide element (1) from a composite glass laminate (3), wherein, The composite glass stack (3) comprises a plurality of glass plates (5) joined together, wherein a light-reflecting layer (7) is disposed between the glass plates (5), wherein the method comprises cutting slices (9) from the composite glass stack (3) along a parallel cutting plane (11), wherein the method further comprises aligning the composite glass stack (3) with the cutting plane (11) such that the light-reflecting layer (7) has a defined orientation relative to the sides (13, 15) of the slice (9) after cutting; wherein the composite glass stack (3) has a plane (16) having a defined orientation relative to the light-reflecting layer (7) within the composite glass stack (3), such that when the cutting plane (11) is parallel to the plane (16) of the composite glass stack (3), the light-reflecting layer (7) within the slice (9) has a correct orientation, wherein the alignment of the composite glass stack (3) with the cutting plane (11) comprises: - Adjust the tilt angle of the plane (16) of the composite glass stack (3) relative to the cutting plane (11) using an autocollimator (22); and - Adjust the position of the composite glass stack (3) along a direction inclined relative to the cutting plane (11), preferably vertical; The composite glass stack (3) is fixedly held on a retainer (23) along its alignment orientation and cut into slices (9), which form blanks for the light guide optical element (1), and the alignment of the composite glass stack (3) is performed outside the cutting device (2).

2. The method according to claim 1, wherein, The composite glass stack (3) includes a large number of light-reflecting layers (7) oriented parallel to the side surface (17) of the composite glass stack (3), and wherein the step of adjusting the position of the composite glass stack (3) in a direction perpendicular to the cutting plane (11) includes adjusting the position of the composite glass stack (3) such that the light-reflecting layers (7) are centered in the slice (9) in a direction perpendicular to the side surface (13, 15).

3. The method according to any one of the preceding claims, wherein, The plane (16) of the composite glass stack (3) having a defined orientation relative to the light reflective layer (7) is the side surface (17) of the composite glass stack (3).

4. The method according to any one of the preceding claims, wherein, The slice (9) is cut from the composite glass stack (3) using a wire saw (21), the wire saw (21) having a large number of parallel segments (180) of one or more cutting wires (18).

5. The method according to any one of the preceding claims, wherein, The step of adjusting the position of the composite glass stack (3) so that the light-reflecting layer (7) is centered in the slice (9) in a direction perpendicular to the sides (13, 15) includes monitoring the position of at least one light-reflecting layer (7) by a camera (24).

6. The method according to any one of the preceding claims, wherein, The autocollimator (22) is configured to be fixed in relation to the cutting device (2), particularly the wire saw (21).

7. The method according to any one of the preceding claims, wherein, The method involves adjusting the orientation of the autocollimator (22) relative to the cutting plane (11); the method includes cutting a first composite glass stack (3) to form a slice (9), and then cutting a second composite glass stack (3), wherein the numerous slices (9) cut from the first composite glass stack and one of their sides (13, 15) are placed on a reference surface (25), and the tilt angle of the inner surface of the slice (9), in particular the light-reflecting layer (7), relative to the reference surface (25) is measured, and an average tilt angle is determined, and wherein the orientation of the autocollimator (22) is corrected according to the average tilt angle, and the second composite glass stack (3) is cut with the tilt angle of the second composite glass stack (3) relative to the cutting plane (11) adjusted in the case where it is in the corrected orientation of the autocollimator (22).

8. The method according to any one of the preceding claims, the method comprising cutting a first composite glass stack (3) to form slices (9), subsequently cutting a second composite glass stack (3), wherein a plurality of slices (9) cut from the first composite glass stack (3) are placed on a reference surface (25), and the tilt angle of the plane (16) of the slices (9) relative to the reference surface (25) is measured, and an average tilt angle is determined, wherein, The orientation of the autocollimator (22) is corrected according to the average tilt angle, and the second composite glass stack (3) is cut when the tilt angle of the second cut composite glass stack (3) relative to the cutting plane 11 has been adjusted using the autocollimator located in its corrected orientation.

9. The method according to any one of the preceding claims, wherein, The composite glass stack (3) is coupled to a sacrificial plate (27) fixedly held on the retainer, and wherein the cutting includes completely cutting through the composite glass stack (3) and further partially cutting into the sacrificial plate (27), wherein after the cutting, the coupling between the sacrificial plate (27) and the composite glass stack (3) is released, so that the slice (9) is separated from the sacrificial plate (27).

10. The method according to any one of the preceding claims, wherein, The method includes at least one of the following steps: - Adjust the position of the composite glass stack (3) relative to the cutting plane (11) so that the position of the light reflective layer (7) relative to the reference position, preferably the center position, within the slice (9) cut from the composite glass stack (3) is less than 0.2 mm, preferably less than 0.1 mm; - Adjust the orientation of the composite glass stack (3) relative to the cutting plane (11) so that the tilt angle of the light-reflecting layer (7) of the slice (9) cut from the composite glass stack (3) is less than 15 arcseconds; - Pre-adjusting the tilt angle about the rotation axis tilted with respect to the direction of movement of the cutting composite glass stack 3, which includes: measuring the position of a point on the surface of the composite glass stack (3) along the path of movement of the composite glass stack (3) during the cutting operation, and adjusting the orientation of the composite glass stack (3), in particular the direction of adjustment, based on the measurement results, such that these positions have equal values ​​in the direction perpendicular to the surface; as well as - Pre-adjustment, wherein at least one camera (24) is used to measure the distance between the face (17) of the composite glass stack (3) and the cutting wire (18), wherein at least two points on the face (17) are spaced apart longitudinally along the cutting wire (18), and then the orientation of the composite glass stack (3) is adjusted such that the distance between the points and the cutting line (18) is equal.

11. The method according to any one of the preceding claims, comprising: - The composite glass stack (3) is fixed on a retainer (23) that is movable by stacked worktables (32, 33, 34); - Using one of the worktables (33), adjust the azimuth angle of the composite glass stack (3) about the axis along the cutting direction; and Use one of the worktables (34) to adjust or manipulate the position of the composite glass stack (3) in a direction inclined to the cutting plane (11).

12. The method according to any one of the preceding claims, wherein, When the retainer (23) is inserted into and secured in the cutting device (2), the retainer (23) has a defined orientation relative to the cutting plane (11), and wherein, when the retainer (23) is disengaged from the cutting device (2) and secured to the alignment device (10), the composite glass stack (3) is aligned with the retainer (23); as monitored by the autocollimator (22), the composite glass stack (3) is aligned with the retainer (23) and secured to the retainer (23) along the alignment orientation, and wherein, the retainer (23) to which the composite glass stack (3) is attached is inserted into and secured to the cutting device (2) such that the composite glass stack (3) has a defined orientation relative to the cutting plane due to its defined orientation relative to the retainer (23).

13. A method for manufacturing a light-guiding optical element (1), comprising: Slices (9) are generated from the composite glass stack (3) using the method according to any one of the preceding claims; The sides (13, 15) of the slice (9) are polished; and the slice (9) is cut along a predefined contour line to obtain the light guide optical element (1).

14. An apparatus for manufacturing a blank for an optical guide element (1) from a composite glass laminate (3), wherein, The composite glass stack (3) comprises a plurality of glass plates (5) joined together and a light-reflecting layer (7) disposed between the glass plates (5); the apparatus comprises a cutting device (2) and a separate alignment device (10), the cutting device (2) for cutting slices (9) from the composite glass stack (3) along a parallel cutting plane (11), the alignment device (11) for aligning the composite glass stack (3) with the cutting plane (11) such that the light-reflecting layer (7) has a defined orientation relative to the sides (13, 15) of the slice (9) after cutting, wherein the composite glass stack (3) has a plane (16) with a defined orientation relative to the light-reflecting layer (7) within the composite glass stack (3), such that when the cutting plane (11) is parallel to the plane (16) of the composite glass stack (3), the light-reflecting layer (7) within the slice (9) has a correct orientation, wherein the apparatus comprises a holder (23) for holding the composite glass stack (3) in its aligned orientation, and wherein the alignment device comprises: - Autocollimator (22), used to monitor the adjustment of the tilt angle of the plane (16) of the composite glass stack (3) relative to the cutting plane (11), and - A device for adjusting the position of the composite glass stack (3) in a direction inclined relative to the cutting plane (11), preferably vertical.

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