METHOD FOR RECOGNIZING MISALIGNMENTS AND/OR CONTAMINATIONS OF OPTICAL SYSTEMS IN SMART GLASSES, AND OPTICAL SYSTEM

Abstract

A method for recognizing misalignments and/or contaminations of optical systems in smart glasses, including at least one laser projector, which is provided for the purpose of outputting at least one light signal forming at least partially an image display of the smart glasses. It is provided that in at least one monitoring step, an at least partial back-reflection of the light signal generated by components of the optical system is detected and examined for deviations from a reference state.

Claims

1. A method for recognizing misalignments and/or contaminations of optical systems in smart glasses, the smart glasses including at least one laser projector which is configured to output at least one light signal forming at least partially an image display of the smart glasses, the method comprising: detecting, in at least one monitoring step, an at least partial back-reflection of the light signal generated by components of the optical system; and examining the back-reflection for deviations from a reference state.

2. The method as recited in claim 1, further comprising: ascertaining misalignments of the optical system by monitoring an increase and/or a change in at least one characteristic signal portion of the back-reflection of the light signal.

3. The method as recited in claim 2, wherein different characteristic signal portions are back-reflected by different misaligned components of the optical system.

4. The method as recited in claim 2, wherein the characteristic signal portions of the back-reflection light signal is characteristic in each case for one particular surface material/surface structure provided specifically for recognition of the misalignments.

5. The method as recited in claim 4, wherein the surface material/surface structure provided specifically for the recognition is/are situated exclusively in one or in multiple border areas of one or of multiple of the components of the optical system.

6. The method as recited in claim 4, wherein the surface material/surface structure is formed by a retroreflector by a retro-reflecting coating, which is optimized for a selected detection wavelength range and/or which includes unambiguous characteristic return-beam properties.

7. The method as recited in claim 1, further comprising: ascertaining misalignments of the optical system by a monitoring of a change in a self-mixing interferometry signal of the laser projector.

8. The method as recited in claim 1, further comprising: ascertaining contaminations by monitoring a change in speckle properties in the back-reflection of the light signal.

9. An optical system in smart glasses, comprising: at least one laser projector configured to output at least one light signal forming at least partially an image display of the smart glasses; at least one detector configured to detect a back-reflection of the light signal; an evaluation unit configured to evaluate back-reflected light signals received by the detector; and at least one component situated in a path of the light signal; wherein the evaluation unit is configured to recognize a misalignment and/or a contamination of the optical system based on an at least partial back-reflection of the light signal generated by one of the at least one of the components.

10. The optical system as recited in claim 9, wherein the component is a MEMS mirror of the laser projector, as a part of an eyeglass lens of the smart glasses, a diffractive optical element being integrated into the eyeglass lens or an optical lens.

11. The optical system as recited in claim 9, wherein the component is coated, in one or in multiple border areas with a surface material and/or surface pattern generating a characteristic reflection or a characteristic diffraction.

12. The optical system as recited in claim 9, wherein the component includes a retroreflector configured to generate a characteristic reflection with a retro-reflecting coating.

13. The optical system as recited in claim 12, further comprising: a further component provided with a further retroreflector, the further retroreflector including a retro-reflecting coating configured to generate a characteristic reflection or a characteristic diffraction, the characteristic reflection generated by the further component differing significantly from the characteristic reflection generated by the component.

14. The optical system as recited in claim 9, wherein the laser projector and the detector are combined in a VCESL including an integrated photodiode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further advantages result from the description of the figures. An exemplary embodiment of the present invention is represented in the figures. The figures and the description contain numerous features in combination. Those skilled in the art will also advantageously consider the features individually and combine them to form meaningful further combinations, in view of the disclosure herein.

[0022] FIG. 1 schematically shows a representation of smart glasses including an optical system, according to an example embodiment of the present invention.

[0023] FIG. 2 schematically shows a representation of the optical system including multiple components, according to an example embodiment of the present invention.

[0024] FIG. 3A schematically shows a representation of a component of the optical system designed as a diffractive optical element, according to an example embodiment of the present invention.

[0025] FIG. 3B schematically shows a representation of a component of the optical system designed as a vertical MEMS mirror, according to an example embodiment of the present invention.

[0026] FIG. 3C schematically shows a representation of a component of the optical system designed as a horizontal MEMS mirror, according to an example embodiment of the present invention.

[0027] FIG. 4 schematically shows a flowchart of a method for recognizing misalignments and/or contaminations of the optical systems in smart glasses, according to an example embodiment of the present invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0028] FIG. 1 schematically shows a representation of smart glasses 12. Smart glasses 12 include a virtual retinal display. Smart glasses 12 include an eyeglass frame 34. Smart glasses 12 include eyeglass lenses 32. Eyeglass frame 34 includes a hinge 68. A frame temple 70 of smart glasses 12 is bendable relative to eyeglass lenses 32 with the aid of hinge 68. Smart glasses 12 include an optical system 10.

[0029] FIG. 2 schematically shows at least one part of optical system 10. Optical system 10 is formed in part by an eyeglass lens 32. Eyeglass lens 32 includes a component 20 of optical system 10. Optical system 10 includes a laser projector 14. Laser projector 14 is designed as a scanned laser projector 14. Laser projector 14 is provided for the purpose of outputting a light signal 16. Light signal 16 generates an image display of smart glasses 12. Light signal 16 may be provided for ascertaining a pupil position, a pupil movement, a pupil shape and/or a pupil size. Laser projector 14 is integrated at least partially into eyeglass frame 34. Laser projector 14 is provided for the purpose of outputting light signal 16 in the form of a scanned laser beam. The scanned laser beam is provided for the purpose of outputting the image display directly onto a retina of an eye 38 of a user. The scanned laser beam output by laser projector 14 includes visible light. The laser beam output by laser projector 14 includes infrared light.

[0030] Optical system 10 includes a detector 28. Detector 28 is provided for detecting a back-reflection of light signal 16. Detector 28 in this case may be designed to be sensitive to visible light and/or sensitive to invisible light (for example, infrared light). Detector 28 is situated “on axis” with the laser beam emitted by laser projector 14. Detector 28 is integrated into laser projector 14. Laser projector 14 and detector 28 are combined in a VCESL (vertical-cavity surface-emitting laser) including an integrated photodiode (ViP).

[0031] Optical system 10 includes components 20, 26, 44, which are situated in a beam path of the laser beam emitted by laser projector 14. Components 20, 26, 44 are situated in a path of light signal 16. One component 20 of optical system 10 is designed as a diffractive optical element (DOE, 36). DOE 36 is designed preferably as a holographic optical element (HOE). DOE 36 is integrated into one of eyeglass lenses 32 of smart glasses 12. DOE 36 is provided for the purpose of deflecting the scanned laser beam in the direction of an eye 38 of a user. DOE 36 is provided for the purpose of at least partially focusing the scanned laser beam into eye 38 of the user. A further component 26, 44 of optical system 10 is designed, for example, as a MEMS mirror 40, 42 of laser projector 14. Optical system 10 may also include multiple additional further components. Further component 26, 44 could, for example, also be designed as an optical element of optical system 10 having a further optical function, such as a lens or as a non-optical element of optical system 10, such as a mounting for optical elements or an aperture. Optical system 10 includes an evaluation unit 30. Evaluation unit 30 is provided for evaluating the measured signals (back-reflection signals) received by detector 28.

[0032] FIGS. 3a through 3c show by way of example three components 20, 26, 44 of optical system 10. FIG. 3a shows a DOE 36. DOE 36 of FIG. 3a is designed as an HOE. FIG. 3b shows a MEMS mirror 40. MEMS mirror 40 of FIG. 3b is designed as a quasi-static vertical mirror of laser projector 14. FIG. 3c shows a further MEMS mirror 42. Further MEMS mirror 42 of FIG. 3c is designed as an oscillating horizontal mirror of laser projector 14. Components 20, 26, 44 of optical system 10 are provided in each case in border areas 22, 24, 46, 48 with a specific surface material and/or with a specific surface pattern. The specific surface material and/or surface pattern generate(s) a characteristic reflection or a characteristic diffraction. The specific surface material and/or surface pattern is/are formed as/by a coating. The specific surface material and/or surface pattern act(s) retro-reflectively. The specific surface material and/or surface pattern is/are formed by a retroreflector. The specific surface material and/or surface pattern is/are formed by a retro-reflecting coating. The characteristic reflections/diffractions generated by respective different components 20, 26, 44 differ significantly from one another. The reflections/diffractions generated by respective different border areas 22, 24, 46, 48 differ significantly from one another. Upper horizontal border area 22 of DOE 36 shown in FIG. 3a exhibits by way of example a first characteristic reflection. Lower horizontal border area 24 of DOE 36 shown in FIG. 3a exhibits by way of example a second characteristic reflection. Left vertical 46 of border area 24 of DOE 36 shown in FIG. 3a exhibits by way of example a third characteristic reflection. Right vertical 48 border area 24 of DOE 36 shown in FIG. 3a exhibits by way of example a fourth characteristic reflection. Border areas 22, 24, 46, 48 are situated around component 20. Border areas 22, 24, 46, 48 in the exemplary embodiment of FIG. 3a do not overlap component 20. In the exemplary embodiments of FIGS. 3b and 3c, border areas 22, 24, 46, 48, however, overlap respective components 26, 44. All of these characteristic reflections of border areas 22, 24, 46, 48 in this example are different and are able to be identified by detector 28 and/or by evaluation unit 30. As a result of the difference in the characteristic reflections, it is possible to ascertain a source of a back-reflection signal detected by detector 28.

[0033] Evaluation unit 30 is provided for the purpose of recognizing a misalignment of optical system 10 based on the at least partial back-reflections of light signal 16 generated by respective components 20, 26, 44. Evaluation unit 30 is provided for the purpose of recognizing a setting of hinge 68 of smart glasses 12 based on the at least partial back-reflections of light signal 16 generated by respective components 20, 26, 44. Evaluation unit 30 is provided for the purpose of recognizing a contamination of optical system 10 based on the at least partial back-reflections of light signal 16 generated by respective components 20, 26, 44. Evaluation unit 30 is provided for the purpose of recognizing a damage to optical system 10 such as, for example, a breakage of one of components 20, 26, 44 of optical system 10 based on the at least partial back-reflections of light signal 16 generated by respective components 20, 26, 44.

[0034] FIG. 4 schematically shows a flowchart of a method for recognizing misalignments and/or contaminations of optical systems 10 in smart glasses 12. In at least one method step 50, light signal 16 is generated and emitted by laser projector 14. In at least one further method step 52, light signal 16 passes optical system 10. When passing optical system 10 (misaligned or aligned), a portion of light signal 16 is back-reflected by components 20, 26, 44 of optical system 10. If a contamination of optical system 10 is now present, the contamination produces a deviation of the back-reflected signal compared to an uncontaminated reference state. If a misalignment of optical system 10 is now present, emitted light signal 16 strikes border areas 22, 24, 46, 48 of components 20, 26, 44 of optical system 10, from where it is back-reflected to detector 28. In the process, different characteristic signal portions are back-reflected by different border areas 22, 24, 46, 48 of misaligned components 20, 26, 44 of optical system 10. In this case, the characteristic signal portions of the back-reflection light signal are characteristic in each case for one particular surface material provided specifically for this recognition. In this case, the surface materials and/or surface patterns may be optimized specifically for particular selected detection wavelength ranges and/or include unambiguous characteristic return-beam properties. To increase the signal, the respective surface materials emitting the characteristic signal portions are formed by a retroreflector, such as a retro-reflecting coating. To simplify the signal evaluation and/or the distinguishability of different back-reflected signals, the surface materials emitting the characteristic signal portions are designed in such a way that they generate (in each case, different) speckle patterns in the reflection of collimated laser light.

[0035] In at least one monitoring step 18, the back-reflection of light signal 16 generated by components 20, 26, 44 of optical system 10 is detected and examined for deviations using the respective reference state of optical system 10 (border area reflections) and/or the respective optical components 20, 26, 44 (SMI method). In monitoring step 18, the back-reflection is detected by detector 28 as a measured signal. In monitoring step 18, the detected measured signal is evaluated and/or analyzed by evaluation unit 30. In at least one sub-step 54 of monitoring step 18, misalignments of optical system 10 are ascertained by a monitoring of an increase and/or a change in at least one signal portion of a back-reflection of light signal 16 characteristic for border areas 22, 24, 46, 48. In at least one further sub-step 60 of monitoring step 18, damages to optical system 10, such as breakages of optical components 20, 26, 44 of optical system 10, are ascertained by a monitoring of an increase and/or a change in at least one characteristic signal portion of a back-reflection of light signal 16 characteristic for border areas 22, 24, 46, 48. In at least one further sub-step 56 of monitoring step 18, misalignments of optical system 10 are ascertained by a monitoring of a change of a self-mixing interferometry signal (SMI signal) of laser projector 14. In at least one further sub-step 62 of monitoring step 18, damages to optical system 10, such as breakages of optical components 20, 26, 44 of optical system 10, are ascertained by a monitoring of a change in the SMI signal of laser projector 14. In at least one further sub-step 58 of monitoring step 18, contaminations of optical system 10 are ascertained by a monitoring of a change in the speckle properties in the back-reflection of light signal 16. In at least one further sub-step 64 of monitoring step 18, contaminations of optical system 10 are ascertained by a monitoring of a change in the SMI signal of laser projector 14. In at least one further method step 66, the result of monitoring step 18 is output to the user.