Method and control unit for producing an optical element

Abstract

The invention relates to a method (300) for producing an optical element (120), the method (300) including a step of detecting (310) an optical parameter of the optical element (100) and a step of forming (320) a mark (120) on the optical element (100) using the optical parameter.

Description

[0001] Method and control unit for producing an optical element

[0002] The approach presented here relates to a method and a control unit for producing an optical element according to the main claims.

[0003] In order to avoid the formation of ghost images or similar aberrations in an optical system, high-precision adjustment is necessary when assembling such an optical system. Such high-precision adjustment is always problematic when, during the manufacture of optical components which are not invariant with regard to their azimuthal alignment, an adjustment rotation process is used which creates rotationally symmetrical surfaces. This means, for example, that when manufacturing a mount for such an optical element or component, the latter is designed to be symmetrical with regard to rotation around the optical axis. Components manufactured in this way therefore have one degree of freedom of rotation around the optical axis. As soon as the optical component is no longer rotationally symmetrical in its shape or optical effect, precise alignment orAdjustment of the optical component with respect to a defined azimuth angle is required, which, however, makes assembly more difficult, more complex or even just delays it.

[0004] Against this background, the present invention has the object of creating a possibility for improving the production of an optical element so that subsequent assembly of an optical system with this optical element can be simplified and accelerated.

[0005] The approach presented here provides a method for producing an optical element, the method comprising the following steps:

[0006] Detecting an optical parameter of the optical element; and

[0007] Forming a mark on the optical element using the optical parameter.

[0008] In this context, an optical parameter can be understood as a value and a property of the optical element that represents or causes a characteristic shaping or deflection of light by this optical element. For example, such an optical parameter can be understood as a polarization direction of the optical element. Detecting can be understood as measuring the optical parameter or a corresponding formation or imprinting of the optical parameter into the optical element. A marking can be understood as a mechanical mark on or at the optical element, which is, for example, visible and / or tactile.

[0009] The approach presented here is based on the realization that the formation of the marking on the optical element can provide an indication of the optical parameter of the optical element without this optical parameter having to be laboriously measured or recorded again. This advantageously makes it possible for the optical element to be adjusted very quickly and easily using the marking when assembling an optical system using this optical element. For example, if the optical element is picked up by a robot arm, aligned using the marking, and then assembled with other components to form an optical system. In this way, complex optical measurement and alignment of the optical element can be avoided, which is cost-effective and results in a shorter production time during the manufacture of this optical system.

[0010] An embodiment of the approach presented here is advantageous in which a polarization direction of the optical element is detected as an optical parameter in the step of detecting. Such an embodiment offers the advantage that, in particular, an alignment of the optical element with respect to a desired polarization direction is an essential aspect for an optical function of the optical element, so that the possibility of using the marking on the optical element now enables a significant improvement or simplification of the use of such an optical element without there being a risk of a significant deterioration in the optical function. In general, all optical components that have rotation-invariant parameters that influence the optical function of the optical element can be adjusted using the approach proposed here.In addition to polarization, this can be the case with the position of the cylinder axis of cylindrical lenses.

[0011] Another favorable embodiment of the approach proposed here is one in which the optical element has a light-shaping element and a holding element carrying the light-shaping element, wherein the marking is formed on or in the holding element in the forming step. A light-shaping element can be understood, for example, as a lens, a polarization filter, or a prism that is capable of changing a property of a light beam and / or a direction of the light beam. Of course, a combination of two or more such elements is also conceivable. A holding element can be understood, for example, as a mount that, for example, consists of a different material than the material of the light-shaping element or has such a material.Such an embodiment offers the advantage that the holding element can be provided with the marking without the need to machine the light-shaping element. This can simplify the manufacture of the optical element.

[0012] An embodiment of the approach proposed here is also conceivable in which a non-rotationally symmetrical marking is formed on the optical element during the forming step. Such an embodiment offers the advantage of being able to very easily and unambiguously determine and use the position and / or orientation of the optical element with respect to the optical parameter using such a marking. Thus, precise alignment of the optical element can be simplified using such a marking, especially when used in optical system manufacturing systems.

[0013] According to another embodiment of the approach proposed here, a shape change, in particular a notch and / or the introduction of a flat spot, can be formed in an edge region of the optical element during the step of forming the marking. Such an embodiment is technically very simple to implement, and such a marking is very easy to identify yet precise to use.

[0014] Specifically, in one embodiment, the shape change can be achieved in the forming step by milling and / or punching the optical element or a part of the optical element. Such an embodiment offers the advantage that the optical element is usually already processed by such a processing step, so that only minimal additional effort is required to additionally apply or incorporate the marking into or onto the optical element. According to a favorable embodiment of the approach presented here, in the forming step, a holding unit with a marking applied to the holding unit can be coupled around a lens element and / or a prism depending on the optical parameter in order to form the marking on the optical element.Such an embodiment offers the advantage that, for example, the marking is already arranged on the holding unit, and the holding unit only needs to be attached to the lens element and / or prism in an appropriately aligned manner depending on the (detected) optical parameter. This advantageously eliminates the need for specific material processing or prevention to form the marking. This, for example, can reduce the time required to manufacture such an optical element.

[0015] The approach presented here is particularly advantageous when the optical element is composed of a combination of a transparent element, e.g., a lens, and a polarization-influencing element, e.g., a polarizing film. Applying a marking to the holding element of such an optical element results in a defined, azimuthal alignment of the polarization axis of the polarization-influencing element with respect to the optical axis when the optical element is inserted into an optical system.

[0016] In this case, a separate measurement of the optical parameter, here the azimuthal position of the polarization axis, can be omitted in the subsequent adjustment process, since this optical parameter is then already known.

[0017] This method can be implemented, for example, in software or hardware, or in a hybrid form of software and hardware, for example, in a control unit. The control unit can also be integrated into a suitable processing machine, which is controlled, for example, by CNC. The processing machine can also be designed as a calibration lathe and perform the method presented here in combination with a calibration turning process.

[0018] The approach presented here further creates a control unit that is designed to carry out, control, or implement the steps of a variant of a method presented here in corresponding devices. This embodiment of the invention in the form of a control unit also allows the problem underlying the invention to be solved quickly and efficiently. For this purpose, the control unit can have at least one computing unit for processing signals or data, at least one memory unit for storing signals or data, at least one interface to a sensor or an actuator for reading in sensor signals from the sensor or for outputting data or control signals to the actuator, and / or at least one communication interface for reading in or outputting data embedded in a communication protocol.The computing unit can be, for example, a signal processor, a microcontroller, or the like, and the storage unit can be a flash memory or a magnetic storage unit. The communication interface can be configured to read in or output data wirelessly and / or via a wired connection. A communication interface capable of reading in or outputting wired data can read this data electrically or optically from a corresponding data transmission line or output it to a corresponding data transmission line, for example.

[0019] In this case, a control unit can be understood as an electrical device that processes sensor signals and outputs control and / or data signals depending on them. The control unit can have an interface that can be implemented in hardware and / or software. In a hardware implementation, the interfaces can, for example, be part of a so-called system ASIC, which contains various functions of the control unit. However, it is also possible for the interfaces to be separate integrated circuits or to consist at least partially of discrete components. In a software implementation, the interfaces can be software modules that are present, for example, on a microcontroller alongside other software modules.

[0020] Also advantageous is a computer program product or computer program with program code that can be stored on a machine-readable carrier or storage medium such as a semiconductor memory, a hard disk memory or an optical memory and is used to carry out, implement and / or control the steps of the method according to one of the embodiments described above, in particular when the program product or program is executed on a computer, a control unit or a device.

[0021] Embodiments of the approach presented here are illustrated in the drawings and explained in more detail in the following description. Figure 1 shows a schematic representation of an embodiment of an optical element;

[0022] Fig. 2 is a schematic cross-sectional view of an embodiment of an optical system;

[0023] Fig. 3 is a flowchart of a method according to an embodiment; and

[0024] Fig. 4 is a block diagram of a control unit according to an embodiment.

[0025] In the following description of advantageous embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, whereby a repeated description of these elements is omitted.

[0026] Figure 1 shows a schematic representation of an embodiment of an optical element 100, which was manufactured or processed, for example, using the method presented here. The optical element 100 comprises a light-shaping element 105, which is configured, for example, as a lens, to which a polarizing film 110 has been adhesively bonded. This polarizing film 110 has been applied to the light-shaping element 105 in such a way that a desired polarization direction is formed by this polarizing film 110. In Figure 1, this polarization direction is indicated by corresponding hatching 115 of the polarizing film 110.The polarization direction can be understood, quite generally, as an optical parameter of the optical element 100, which is particularly relevant for the subsequent installation of this optical element 100 in an optical system, since otherwise such an optical system would no longer have the desired optical function or effect.

[0027] In order to facilitate the installation of such an optical element into the optical system without the need for a measurement of this optical parameter each time an optical element 100 is installed in the optical system, a marking 120 is applied and / or introduced onto the optical element 100, here in particular in the edge region 125 of the optical element 100, as shown in Figure 1. This marking 120 can, for example, consist of a mechanically and / or optically detectable notch or flat spot that has a predetermined relationship to the optical parameter. The marking 120 should be applied in such a way that a clear conclusion about the optical parameter can be drawn from the marking 120, so that incorrect installation of the optical element 100 during the assembly of an optical system can be ruled out as far as possible.

[0028] It is also conceivable that the edge region 125 is formed by a separate holding unit 130 (which can also be synonymously referred to as a holding element), which, for example, consists of or is manufactured from a material (e.g., plastic or metal) that differs from a material (e.g., glass or transparent plastic) of the light-shaping element 105. This can, for example, simplify or accelerate the application or insertion of the marking 120 in this edge region 120, for example because machining this holding element or the holding unit 130 is easier than machining the light-shaping element 105.

[0029] The marking can be applied or inserted in combination with an adjustment turning process. In this case, the holding element 130 of the optical element 100 is machined such that a rotationally invariant parameter, e.g., the optical axis of the optical element 100, is sufficiently aligned with respect to a reference axis. Subsequently or in parallel, the marking 120 is applied or inserted onto the edge region 125 such that a non-rotationally invariant parameter, here the position of the polarization axis of the polarizing film 110, undergoes a defined azimuthal alignment. During the subsequent insertion of the optical element 100 into an optical system 200, the marking 120 ensures that the azimuthal alignment of the polarizing film is maintained and does not have to be metrologically verified in a separate adjustment step.In other words, the engraved or applied marking 120 enables a simple, passive adjustment of the optical element 100. The engraved or applied marking 120 can be easily performed using an alignment lathe or machining machine, since this machine has the necessary measuring or manufacturing technology.

[0030] Fig. 2 shows a schematic cross-sectional view of an embodiment of an optical system 200 in which an optical element 100 according to an embodiment shown in Figure 1 is installed. For example, the optical system can be an imaging system for VR glasses, in particular a pancake lens, whose function requires a clearly defined rotation of the polarization of the light rays incident into the imaging system. If the optical element 100 is not installed precisely enough in the optical system 200, the optical function or effect of the optical system 200 can be partially severely impaired due to inaccurate adjustment with respect to a rotation angle 210.In order to avoid the need for a complex step of measuring or recording this optical parameter during assembly of the optical element 100 into the optical system 200, the marking 120 of the optical element 100 can now be used, since this optical marking has a predefined relationship with the optical parameter previously recorded during the manufacture or processing of the optical element 100. Thus, only an alignment of the optical element 100 or the marking 120 of the optical element 100 needs to be performed, which can, however, be easily implemented optically or mechanically by a corresponding automated manufacturing machine for the production of the optical system 200.

[0031] In summary, the problems described above can be improved by measuring the polarization direction during the alignment turning process of an optical element, such as a (mounted) pancake lens, and then generating a reference geometry, such as a marking, on the mount, for example, using an alignment turning machine. In this way, the optical element 100, such as the pancake lens used here, and the polarization film can be passively adjusted at the same time, thus enabling adjustment-free assembly.

[0032] In detail, the problems mentioned above can be solved by, for example, creating a further reference surface as a marking 120, for example on the mount as a holding unit 130, during the turning process, with the aid of which the mounted optics or the optical element 100 can now additionally be passively adjusted in angle about an optical axis and thus mounted without the need for an additional, active measuring step.

[0033] As a concrete application, the approach presented here could be used, for example, in a method for manufacturing a pancake lens as an optical element 100, which can be machined on an alignment lathe or milling machine in such a way that the orientation of the polarization filter is incorporated into the reference surface or aligned with respect to the reference surface as a marking, so that no further measurement of the polarization direction as an optical parameter is necessary during subsequent assembly. The approach presented here can be applied wherever optical components are to be installed precisely, i.e., advantageously passively adjusted, but at the same time should be installed in a defined angular position in an overall system.In these cases, the geometry of the mount including the marking can be designed (for example in a D-shape) so that an angular alignment is achieved by passive adjustment, such passive adjustment being made possible by aligning the optical element 100 using the marking 120 and without a concrete detection of the optical parameter itself.

[0034] In the optical element 100 shown here, the mounted lens can also be understood as a light-shaping element 110, which has a polarizing film 115. During the adjustment turning process, the mount is machined as a holding unit 130. With respect to the angular position of the polarizing film 115, a non-rotationally symmetrical reference surface is applied as a marking 120 to the mount or holding unit 130 (for example, in the form of a flattened area or a D-shape). Using this additional surface as a marking, the degree of freedom of rotation can be effectively restricted, and the optical element 100 can be mounted exclusively at the correct angle, which can be detected by evaluating the position of the marking 120.

[0035] Figure 3 shows a flow diagram of an embodiment of a method 300 for producing an optical element 100, wherein the method 300 comprises a step 310 of detecting an optical parameter of the optical element 100 and a step 320 of forming a marking 120 on the optical element 100 using the optical parameter.

[0036] Figure 4 shows a flowchart of an embodiment of a control unit 400 for producing an optical element 100, wherein the control unit 400 has a unit 410 for detecting an optical parameter of the optical element 100 and a unit 420 for forming a marking 120 on the optical element 100 using the optical parameter. The control unit 400 is a component of a processing machine (not shown here), in particular an alignment lathe.

Claims

Claims 1 . A method (300) for producing an optical element (120), the method (300) comprising the following steps: Detecting (310) an optical parameter of the optical element (100); and - forming (320) a marking (120) on the optical element (100) using the optical parameter.

2. Method (300) according to claim 1, wherein in the step (310) of detecting as an optical parameter a polarization direction of the optical element (100) is detected.

3. Method (300) according to claim 1, wherein in the step (310) of detecting as an optical parameter the orientation of a cylinder axis or surface of the optical element (100) is detected.

4. Method (300) according to one of the preceding claims, wherein the optical element (300) comprises a light-shaping element (105, 110) and a holding element (130) carrying the light-shaping element (105, 110), wherein in the forming step (320) the marking (120) is formed on or in the holding element (130).

5. The method (300) according to any one of the preceding claims, wherein in the forming step (320) a non-rotationally symmetric marking (120) is formed on the optical element (100).

6. Method (300) according to one of the preceding claims, wherein in the forming step (320) a change in shape, in particular a notch and / or an introduction of a flat spot, is formed in an edge region of the optical element as a marking (120).

7. Method (300) according to claim 5, wherein in the step (320) of forming the shape change is effected by milling and / or punching the optical element (100) or a part (105, 130) of the optical element (100).

8. The method (300) according to any one of the preceding claims, wherein the steps of detecting (310) and forming (320) are performed in combination with an alignment rotation process of the optical element (100).

9. Control unit (400) configured to execute and / or control the steps (310, 320) of the method (300) according to one of the preceding claims in corresponding units (410, 420).

10. Computer program which is configured to execute and / or control the steps (310, 320) of the method (300) according to one of the preceding claims on a control unit (400).

11. A machine-readable storage medium on which the computer program according to claim 10 is stored.

Images